TW201728870A - Device for measuring characteristics of optical element - Google Patents

Abstract

To provide a device for: simultaneously radiating converging light rays that have a ring-shaped light intensity distribution and parallel light rays that are radiated near the center of a lens being tested, as viewed from the optical axis of a reflected-light sensor unit; and measuring the characteristic values of the lens being tested. Furthermore, to provide a device for measuring the degree of misalignment of the surface of a lens, the device measuring the light-condensing position of ring-shaped converging light rays that have passed through the lens being tested or of parallel light rays that are radiated near the center of the lens being tested, whereby it is possible to measure the degree of misalignment of the surface of the lens being tested without rotating the lens being tested. A device for measuring the characteristics of an optical element provided with a ring-shaped-converging-light-ray-radiating unit for irradiating an optical element being tested with converging light rays that have a ring-shaped light intensity distribution and parallel light rays, wherein the shape characteristics of the optical element being tested are measured by analyzing the intensity or the optical path of light rays that have passed through the optical element being tested or that have been reflected from the obverse surface or reverse surface of the optical element being tested, where the obverse surface is the surface of the optical element being tested that is closer to the ring-shaped-converging-light-ray-radiating unit, and the reverse surface is the surface opposite from the obverse surface.

Description

Optical element characteristic measuring device

The present invention relates to a device for determining a detected light by simultaneously irradiating a focused light whose light intensity distribution is annular from the optical axis of the reflected light sensor portion and a parallel light that is irradiated near the center of the detected lens. The characteristic value of the lens. More particularly, the present invention relates to an apparatus for measuring the thickness of a thin type of test lens having a thickness of 200 μm or less and a lens deviation amount measuring apparatus for adjusting a position of a lens to be inspected. After the lens central axis of the lens (the normal to the first surface of the lens to be inspected) and the optical axis of the reflected light sensor unit are matched, the ring-shaped focused light transmitted through the lens to be inspected is measured or irradiated near the center of the lens to be inspected. The position of the condensed point of the parallel ray is such that the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

In the prior art, as shown in Fig. 1, in order to measure the thickness of an optical element such as a lens, there is a technique in which the optical element 11 to be inspected is disposed in the displacement gauge 10a and the displacement On the straight line of the gauge 10b, the two displacement meters 10a and 10b irradiate the light beams 12a and 12b on the optical element 11 to be inspected, respectively, and measure the surface of the optical element 11 to be inspected measured by one of the displacement meters 10a. The distance a1 and the distance a2 measured by the other displacement meter 10b to the back surface of the optical element 11 to be inspected, Further, the distance a1 and the distance a2 are subtracted from the distance a0 between the displacement gauge 10a and the displacement gauge 10b, and the thickness of the optical element 11 to be inspected is measured. For example, a technique for measuring the thickness of an optical element by using two optical displacement meters is disclosed in Japanese Laid-Open Patent Publication No. Hei 1-235806 (Patent Document 1) and Japanese Patent Publication No. Hei 10-239046 (Patent Document 2).

Further, as a prior art in which the thickness of the optical element is measured using one sensor portion 12, as shown in Fig. 2(A), there is a technique for measuring the thickness of the optical element by a non-contact method, that is, In this technique, the focused light 13 is irradiated onto the optical element 15 to be inspected disposed on the holding holder 14, while moving the reference plane of the rotating platform 16 so that the optical element 15 to be inspected is along the second drawing (B). The light intensity of the image generated on the front and back surfaces of the optical element 15 to be inspected, which is imaged by the imaging optical system not shown in the figure, is measured while moving in the z-axis direction as shown. And, using the processing unit not shown in the figure, the light intensity with respect to the z-axis is sampled to obtain digitized data, and the maximum values of the two light intensities are extracted, based on the z-axis intervals (measured value d), in order to calculate The thickness of the optical element 21 to be inspected.

In addition, as a device for measuring the amount of eccentricity of a lens, Japanese Laid-Open Patent Publication No. 2007-206031 (Patent Document 3) discloses a transmissive eccentricity measuring device that uses a peripheral lens of the lens to be inspected. Rotate so that the amount of eccentricity of the lens to be inspected can be measured.

In addition, Japanese Laid-Open Patent Publication No. 2008-298739 (Patent Document 4) and JP-A-2007-327771 (Patent Document 5) each disclose an eccentricity measuring device that passes one side of the eccentricity measuring device. Make checked The surface to be inspected of the optical element (detected lens) is rotated around a predetermined rotation axis, and an image of a predetermined shape is imaged on the focal plane of the inspection surface, and the measurement is relayed via the inspection surface. The image of the index imaged on the imaging surface is the radius of a circle that moves as the circular trajectory is traced as the image of the rotated image of the surface to be examined, in order to obtain the eccentricity of the surface to be inspected.

[Previous Technical Literature] Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 1-235806

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 10-239046

Patent Document 3: Japanese Laid-Open Patent Publication No. 2007-206031

Patent Document 4: Japanese Laid-Open Patent Publication No. 2008-298739

Patent Document 5: Japanese Laid-Open Patent Publication No. 2007-327771

In the thickness measuring apparatus for an optical element disclosed in Patent Document 1 and Patent Document 2, since two optical displacement meters are required, there is a problem that the size of the apparatus is large and the cost is increased.

Further, in the thickness measuring apparatus of the optical element composed of one non-contact type sensor of the prior art, as shown in FIG. 3, when the condensing point 202 exists on the surface 203a of the optical element 203 to be inspected, Although the image 204a is generated on the surface 203a of the optical element 203 to be inspected of the focused light 201 and the image 204b is produced on the back surface 203b of the optical element to be inspected, the image 204a generated on the surface 203a and the image generated on the back surface 203b are produced. 204b are both focused optical axis 210, i.e., centered on Z and overlapped together, so it is difficult to image 204a Separate from and measure like 204b. Further, for a thin optical element (t to 200 μm), the light intensity of an image obtained by measuring while moving the rotary table in the z-axis direction is shown in Fig. 4, which shows the z-axis. The value is taken as the horizontal axis, and the measured light intensity of the digitized data is taken as the vertical axis, and is represented as a result of the graph. As shown in Fig. 4, the difference between the maximum value and the minimum value of the light intensity of the image is relatively small, and the changes in the mountains and valleys of the graph are slow. As will be described later, Fig. 4 shows that it is difficult to measure and correct and trust. The interval between the two maxima of the high sex corresponds to the z-axis (measured value d).

Next, regarding the apparatus for measuring the amount of eccentricity of the lens, the upper surface (hereinafter also referred to as "first surface") and the lower surface (hereinafter also referred to as "first surface") of the convex-shaped optical lens (hereinafter also referred to as "inspected lens") Also known as the "second side") are spherical. Then, the centers of the upper surface and the lower surface are not located on the optical axis of the design of the lens to be inspected, and surface deviation sometimes occurs during the manufacturing process. Because of such a surface deviation, eccentricity (eccentricity) occurs in the lens to be inspected. For example, a process of measuring the amount of eccentricity for each batch of optical lenses and checking the quality is beneficial. In the prior art, as described above, the measuring device based on the method for measuring the core skew amount and the surface skew angle by rotating the lens to be inspected is used for the amount of surface deviation (eccentricity) of the lens to be inspected. Determination.

In recent years, as the diameter of the lens to be inspected is further progressing, it is more difficult to rotate the lens to be inspected with high precision.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an apparatus which emits focused light having a ring-shaped light intensity distribution and is irradiated on a lens to be inspected by simultaneously irradiating an optical axis of the reflected light sensor portion. The parallel light rays near the center are used to determine the characteristic values of the lens to be inspected. The invention In particular, it is an object of the invention to provide a device for measuring the thickness of a thin test lens having a thickness of 200 μm or less and a lens deviation amount measuring device for adjusting the position of the lens to be inspected. After the lens central axis of the lens (the normal to the first surface of the lens to be inspected) and the optical axis of the reflected light sensor unit are matched, the ring-shaped focused light transmitted through the lens to be inspected is measured or irradiated near the center of the lens to be inspected. The position of the condensed point of the parallel ray is such that the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

The above object of the present invention can be achieved by an optical element characteristic measuring apparatus provided with focused light for making a light intensity distribution in a plane perpendicular to an optical axis and present on the optical axis. The parallel light beam at the center of the light intensity distribution is irradiated onto the annular focused light irradiation light portion on the optical element to be inspected, and the surface of the optical element to be inspected on the side of the light-emitting portion of the annular focused light is used as a surface. The opposite side of the surface is the back surface; and the intensity of the light reflected by the surface or the back surface of the optical element to be inspected is analyzed, the intensity of the light transmitted through the optical element to be inspected is analyzed, or the optical path of the light is analyzed. The shape characteristics of the aforementioned optical element to be inspected.

The above object of the present invention can also be achieved more effectively by the fact that the annular focused light illuminating light portion has a light source, a first optical element and a first lens, and the light source and the first optical body along the optical axis The light source, the first optical element, and the first lens are disposed in the order of the element and the first lens; a ring-shaped void perpendicular to the optical axis is formed in the first optical element; and has a ring shape The first lens having a diameter of a small diameter inside the gap is disposed in the first optical element such that the optical axis and the optical axis of the first lens are substantially coincident; or a reflected light detecting portion and a processing portion are provided. The reflected light detecting unit irradiates the annular focused light onto the optical element to be inspected, and causes a first annular image generated on a surface of the optical element to be inspected and a second annular image generated on a back surface of the optical element to be inspected. The annular image is imaged on the light receiving surface, and data for calculating the light intensity of the first annular image and the second annular image is generated; Calculating the thickness of the optical element to be inspected with respect to a change in the distance of the optical intensity of the optical element to be inspected in the optical axis direction; or the optical element to be inspected is a lens; and the processing unit detects the data based on the data The two maximum values of the change in the light intensity of the first annular image and the second annular image, and the measured value of the difference in the moving distance of the optical element to be inspected corresponding to the two maximum values is used. d. a refractive index n of a material of the optical element to be inspected, a radius of curvature r of the optical element to be inspected, a center point of the curvature radius r, and the aforementioned focused light as an angle formed by the optical axis and the focused light Calculating the thickness t of the lens of the optical element to be inspected by the condensing angle θ ₁ ; or the point C at which the annular focused light of the surface of the optical element to be inspected is refracted and the back surface of the optical element to be inspected The slope a and the intercept b of the line segment BC of the annular spot B are set to

And b = r - d , use

Calculating the distance e between the point C and the optical axis of the ring-shaped focused light. When the radius of curvature r is positive (the optical element to be inspected is a convex lens), the sign of the distance e is positive. In the case where the radius of curvature r is negative (the optical element to be inspected is a concave lens), the sign of the distance e is a negative value, and is used.

Calculating the thickness t of the lens of the optical element to be inspected; or the optical element characteristic measuring apparatus includes a reflected light sensor unit, a transmitted light sensor unit, and a data processing unit, wherein the reflected light sensor unit has a ring shape Focusing light irradiates the aforementioned annular focused light irradiation light portion on the optical element to be inspected, and generates a first fusion for calculating a reflection angle of an optical axis of the annular parallel light reflected on the surface of the optical element to be inspected Optical position data; the transmitted light sensor unit generates second condensed position data for calculating a condensed spot position of the ray of the light irradiated from the annular focused light and transmitted through the optical element to be inspected; and the data processing unit Calculating the reflection angle based on the first condensed position data, calculating the condensed spot position of the light transmitted through the optical element to be inspected based on the second condensed position data; and the data processing unit is based on the first concentrating position Data adjusts the position of the aforementioned optical element to be inspected so that the lens central axis of the aforementioned optical element to be inspected and the aforementioned ring The optical axis of the focused light-illuminating light portion becomes uniform, and based on the position of the light-converging point, the surface deviation amount Δ _{2 of the} optical element to be inspected is calculated without rotating the optical element to be inspected; or the optical element to be inspected is a lens; the processing unit uses a deviation amount Δ ₁ calculated based on the position of the condensed point of the transmitted parallel ray passing through the vicinity of the center of the optical element to be inspected, a refractive index n of a material of the optical element to be inspected, and the optical inspection target Calculating the surface deviation amount Δ ₂ by the radius of curvature r _{1 of the} surface of the element, the radius of curvature r _{2 of the} back surface of the optical element to be inspected, and the thickness t of the optical element to be inspected; or The surface deviation amount Δ ₂ is calculated as described above; or the optical element to be inspected is a lens; and the processing unit transmits the focused light based on the focus on the side of the reflected light sensor unit of the optical element to be inspected. a refraction angle θ ₁ ' of the transmitted parallel ray calculated by the condensed spot position of the transmitted light sensor portion of the transmitted parallel light ray obtained by the optical element to be inspected, a refractive index n of a material of the optical element to be inspected, and the aforementioned Calculating the aforementioned surface deviation amount Δ ₂ by using the curvature radius r ₂ of the aforementioned back surface of the optical element; or, using The above-described surface deviation amount Δ ₂ is calculated; or the focused light obtained by arranging three or more light beams at substantially equal intervals on the circumference is used instead of the annular focused light; or the three or more beams are made. More than three holes through which the light beam passes are formed in the aforementioned first optical element.

According to the optical element characteristic measuring apparatus of the present invention, the reflected light sensor is caused by simultaneously irradiating the focused light whose light intensity distribution is annular and the parallel light which is irradiated near the center of the detected lens from the optical axis of the reflected light sensor portion. The optical axis of the portion is aligned with the optical axis of the lens to be inspected, and the intensity of the light reflected by the surface of the lens to be inspected or the optical path (the position of the collected light) or the intensity or optical path of the light transmitted through the lens to be inspected is analyzed. The position of the light) so that the characteristic value of the lens to be inspected can be determined.

In particular, according to the optical element characteristic measuring apparatus of the present invention, the change in the light intensity of the ring-shaped image on the surface and the back surface of the lens to be inspected is observed by the optical element having the circular transmission hole (slit), so that the thin type can be measured. The thickness of the lens to be inspected (thickness t~200 μm or less).

Further, according to the optical element characteristic measuring apparatus of the present invention, the position of the lens to be inspected is adjusted so that the lens central axis of the lens to be inspected (the normal of the first surface of the lens to be inspected) and the optical axis of the reflected light sensor portion become identical. Thereafter, by measuring the position of the condensing point of the light transmitted through the lens to be inspected, the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

29‧‧‧Circular focused light illumination optical system

30‧‧‧Optical system

31‧‧‧Light source (eg laser diode)

32‧‧‧ collimator lens

33‧‧‧half mirror

34‧‧‧Optical components

34a‧‧‧Circular transmission hole

34b‧‧‧ small diameter lens

39‧‧‧Optical components

40‧‧‧ lens

41‧‧‧CCD camera

42‧‧‧Processing Department

43‧‧‧Rotating platform

44‧‧‧Optical components

45‧‧‧ lens

46‧‧‧CCD camera

47‧‧‧Automatic Collimator Department

48‧‧‧Reflected Light Detection Department

50a‧‧‧ focused light

50b‧‧‧ parallel light

110‧‧‧Detected lens 10

110a‧‧‧First 10a

110b‧‧‧second side 10b

111‧‧‧Inspected lens holding unit

112‧‧‧ lens holder

113‧‧‧ lens holder to maintain the platform

120‧‧‧ lens surface deviation measuring device

121‧‧‧Detected lens holder

122‧‧‧ lens holder holding mechanism platform

123‧‧‧Reflective light sensor unit

123a‧‧‧Light source

123b‧‧‧Reflective light sensor automatic collimator

124‧‧‧Transmission light sensor unit

124a‧‧‧Transmission light sensor automatic collimator

124b‧‧‧Light Sensors Division

124c‧‧‧Transmission light sensor unit retention mechanism platform

125‧‧‧Data Processing Department

126‧‧‧ monitor

130‧‧‧ lens surface deviation measuring device

130a‧‧‧The Ministry of Inspection

130b‧‧‧Reflective light sensor unit

130c‧‧‧Transmission light sensor unit

130d‧‧‧Data Processing Department

130e‧‧‧ display

131a‧‧‧Detected lens

131b‧‧‧Detected lens holder

131c‧‧‧Lens holder retention mechanism

132‧‧‧Light source department

132a‧‧‧Light source (eg laser diode)

132b‧‧‧ lens (focus distance f2)

132c‧‧·half mirror

133‧‧‧Optical components 33

134‧‧‧ lens (focus distance f4)

135‧‧‧Optical components (eg pinholes)

136‧‧‧Reflective light sensor automatic collimator

136a‧‧‧ lens (focus distance f7)

136b‧‧‧Reflective light sensor unit light receiving device

137‧‧‧Transmission optical sensor optical system

137a‧‧ lens (focus distance f11)

137b‧‧‧transmitted light sensor unit light receiving device

138‧‧‧Transmission light sensor automatic collimator

138a‧‧ lens (focus distance f10)

138b‧‧‧Transmission light sensor automatic collimator light receiving device

138c‧‧·half mirror

139‧‧‧Transmission light sensor unit holding mechanism platform

141a‧‧‧Reflective light sensor unit

141b‧‧‧Transmission light sensor unit

141c‧‧‧Data Processing Department

141d‧‧‧ monitor

142‧‧‧Adjusting lens (plano-convex lens)

143‧‧‧Inspected lens holder

144‧‧‧Transmission light sensor unit holding mechanism platform

145a‧‧‧Circular focused light

145b‧‧‧Circular reflected light

146‧‧‧Light path

Fig. 1 is a schematic block diagram showing a thickness measuring device of an optical element composed of two non-contact displacement meters as a prior art.

Fig. 2(A) is a view showing the configuration of a thickness measuring device for an optical element comprising a non-contact type displacement meter as a prior art.

Fig. 2(B) is a view showing the xyz coordinate system of the measuring device shown in Fig. 2(A).

Fig. 3 is a view showing the image generated on the surface of the optical element to be inspected and the surface of the optical element to be inspected when the focused light is present on the surface of the optical element to be inspected in the thickness measuring apparatus of the optical element of the prior art. A picture like the look.

Fig. 4 is a view showing the reflected light from the optical element to be inspected in the case where the measurement is performed using the beam of the focused light used in the prior art in the thickness measuring device of the optical element composed of a non-contact type displacement meter. A plot of the change in light intensity versus the z-axis.

In the measurement device according to the embodiment of the present invention, the annular focused light illumination optical system capable of simultaneously irradiating the focused light having a circular light intensity distribution and the parallel light irradiated near the center of the detected lens Detailed structure diagram.

Fig. 6 is a view showing the shape of the optical element 34 of the annular focused light irradiation optical system in the embodiment of the present invention.

Fig. 7 is a detailed configuration diagram showing a configuration in which an autocollimator unit is added to an annular focused light irradiation optical system in the measurement device according to the embodiment of the present invention.

Fig. 8 is a view showing the shape of an optical element of the reflected light detecting portion in the embodiment of the present invention.

Fig. 9(A) is a configuration diagram of an optical element thickness measuring apparatus in the first embodiment of the present invention.

9(B) to 9(D) are coordinate systems of the optical element thickness measuring device (integral structural view), wherein FIG. 9(B) shows the x-axis, the y-axis, and the z-axis of the reference plane. Fig. 9(C) is a view showing a swing angle θx; and Fig. 9(D) is a view showing a swing angle θy.

Fig. 10 is a view showing the shape of an optical element of the auto-collimator unit in the first embodiment of the present invention.

Fig. 11 is a view showing a state in which focused light is reflected on the surface of the optical element to be inspected in the optical element thickness measuring apparatus according to the first embodiment of the present invention.

Fig. 12 is a view showing the focus of the optical element thickness measuring apparatus according to the first embodiment of the present invention, which has an annular light intensity as viewed from the optical axis of the focused optical beam. A view of the image generated on the surface of the optical element to be inspected and the image generated on the back surface of the optical element to be inspected when light is present on the surface of the optical element to be inspected.

Fig. 13 is a view showing the optical element thickness measuring apparatus according to the first embodiment of the present invention, in which the focused light having an annular light intensity is present on the back surface of the optical element to be inspected as viewed from the optical axis of the focused optical light. A diagram of the image produced by the surface of the optical element to be inspected and the image produced on the back side of the optical element to be inspected.

In the optical element thickness measuring apparatus according to the first embodiment of the present invention, the condensed spot is present on the surface of the optical element to be inspected, and the surface image is formed on the light receiving surface of the CCD camera. A map of the surface image.

In the optical element thickness measuring apparatus according to the first embodiment of the present invention, the condensed spot is present on the back surface of the optical element to be inspected, and the back surface image is formed on the light receiving surface of the CCD camera. A picture of the back side imaged.

(A) of the optical element thickness measuring apparatus according to the first embodiment of the present invention, wherein the optical element having the annular through hole blocks the condensed spot from being present inside the optical element to be inspected. The surface image and the back image are both images of a portion of the annular surface imaged on the light receiving surface of the CCD camera.

Fig. 15(B) is a view showing the optical element thickness measuring apparatus according to the first embodiment of the present invention, in which the optical element having the annular through hole blocks the thickness of the condensed spot present in the optical element to be inspected. In the vicinity of the center of the direction, both the surface image and the back image are imaged on the annular back surface imaged on the light receiving surface of the CCD camera.

Fig. 16 is a view showing the thickness of the optical element to be inspected according to the first embodiment of the present invention, in which the surface of the optical element to be inspected is measured using focused light having an annular light intensity as viewed from the optical axis of the focused optical beam. And the light produced by the back In the case of intensity, a graph of changes in the light intensity of the reflected light from the optical element to be inspected with respect to the change in the z-axis.

Fig. 17 is a view showing the thickness of the optical element to be inspected according to the first embodiment of the present invention, in which the surface of the optical element to be inspected is convex (r > 0), and the focused light is incident on the convex shape. The optical element is a view of a state in which the surface of the optical element to be inspected is refracted and then collected on the back surface of the optical element to be inspected.

In the optical element thickness measuring apparatus according to the first embodiment of the present invention, when the surface of the optical element to be inspected is concave (r<0), the focused light is incident on the concave shape. The optical element is a view of a state in which the surface of the optical element to be inspected is refracted and then collected on the back surface of the optical element to be inspected.

Fig. 19 is a view showing a focused spot of the focused optical element thickness measuring device according to the second embodiment of the present invention, in which the focused light having the light intensity of the light beam disposed along the virtual ring is viewed from the focused optical axis. A view of the image generated on the surface of the optical element to be inspected and the image generated on the back surface of the optical element to be inspected when the surface of the optical element is inspected.

Fig. 20(A) is a view showing the outline of the optical element 61 of the optical element thickness measuring apparatus to be inspected according to the second embodiment of the present invention.

Fig. 20(B) is a view showing the outline of the optical element 62 of the optical element thickness measuring apparatus to be inspected according to the second embodiment of the present invention.

Fig. 21 is a view showing the optical element of the thickness of the optical element to be inspected according to the third embodiment of the present invention, in which the focused light is incident on the surface of the optical element to be inspected (the flat surface of the radius of curvature r = )) and the back surface is flat. On the surface 512a A diagram of the state of being condensed on the back side after refraction.

Fig. 22 is a view for explaining the definition of the amount of surface deviation of the lens to be inspected measured by the lens surface deviation amount measuring device according to the fourth embodiment of the present invention.

Fig. 23 is a block diagram showing a lens surface deviation amount measuring apparatus according to a fourth embodiment of the present invention.

Fig. 24 is a detailed configuration diagram of a lens surface deviation amount measuring apparatus according to a fourth embodiment of the present invention.

Fig. 25(A) is a view showing the outline of an optical element of a ring-shaped ray which is measured by the amount of surface deviation of the lens according to the fourth embodiment of the invention.

Fig. 25(B) is a view showing the outline of a pinhole type optical element which converts the annular ray of the lens according to the fourth embodiment of the invention.

Fig. 26 is a view showing an optical path of a ring-shaped focused light and a parallel ray passing through a vicinity of a central axis of the lens in the initial setting of the lens surface deviation amount measuring device according to the fourth embodiment of the present invention.

Fig. 27 is a view showing a state in which the optical axis of the reflected ray on the first surface of the lens to be detected becomes a parallel ray that does not coincide with the central axis of the lens and is reflected in the fourth embodiment of the present invention.

Fig. 28 is a view showing a state in which the optical axis of the reflected ray on the first surface of the lens to be detected becomes a parallel ray that coincides with the central axis of the lens and is reflected in the fourth embodiment of the present invention.

According to a fourth embodiment of the present invention, in the fourth embodiment of the present invention, the shape of the ring-shaped focused light that is irradiated from the reflected light sensor portion to the lens to be inspected and the annular focused light are converted into the first surface of the lens to be inspected. Parallel light and reflected Figure.

Fig. 30 is a view showing a state in which the parallel light ray is refracted by the surface deviation amount Δ ₂ generated on the second surface of the lens to be inspected in the fourth embodiment of the present invention.

Fig. 31 is a view showing the fourth embodiment of the present invention, in which the focused light of the optical axis coincides with the central axis of the lens of the lens to be inspected is incident on the lens to be inspected, and then the parallel rays which are inclined with respect to the central axis of the lens are inspected. A diagram of the appearance of the lens.

The measuring device of the present invention is configured to simultaneously illuminate the focused light having a circular light intensity distribution from the optical axis of the reflected light sensor portion and the parallel light that is irradiated near the center of the detected lens to cause the reflected light sensor portion to be reflected. The optical axis coincides with the optical axis of the lens to be inspected, and the intensity or optical path of the light reflected by the surface of the lens to be inspected (for example, the position of the collected light) or the intensity or optical path of the light transmitted through the lens to be inspected is analyzed (for example) , the position of the concentrated light), in order to determine the size or shape characteristics of the lens to be inspected.

Here, in the measuring apparatus according to the embodiment of the present invention, the annular focused light irradiation optical system 29 that can simultaneously irradiate the focused light having a circular light intensity distribution and the parallel light that is irradiated near the center of the detected lens can be used. The order in which the light is transmitted is described for the relationship between the respective components and the functions of the respective components. Fig. 5 is a detailed structural view of the annular focused light irradiation optical system 29.

First, a light source 31 (for example, a laser diode) is disposed at a focal length f1 of the collimator lens 32, and the light emitted from the light source 31 passes through The collimator lens 32 is converted into parallel rays. The parallel rays are converted into parallel annular rays 49a via optical elements 34 having annular transmission holes. Then, the parallel annular ray 49a is converted into the annular focused light 50a via the lens 35 disposed at the propagation destination and having the focal length f2, and is emitted. On the other hand, the parallel ray 49b near the center of the optical axis is condensed at a point N from the focal length f4 of the small-diameter lens 34b via the small-diameter lens 34b disposed at the optical element 34 and having the focal length f4. Then, the lens 35 having the focal length f2 via the focal point distance from the point N is again converted into the parallel ray 50b. As a result, the annular focused light irradiation optical system 29 can simultaneously emit the annular focused light 50a and the parallel light 50b. Also, the annular focused light 50a and the parallel ray 50b have a common optical axis.

Also, Fig. 6 shows the shape of the optical element 34. The optical element 34 has a configuration in which the annular member 34g is disposed inside the annular member 34h on the outer side, and the small-diameter lens 34b having the focal length f4 is disposed on the inner annular member 34g. Since the optical element 34 forms the circular transmission hole 34a, the optical element 34 can convert the incident light into a ring-shaped light having a diameter within a predetermined range and transmit it. Further, since the small-diameter lens 34b having the focal length f4 is disposed near the center of the optical element 34, the optical element 34 converts the parallel light into focused light. Further, the optical element 34 has an annular member 34g as a holder for supporting the small-diameter lens 34b. Further, since the transmission hole 34a is a space (space) between the annular member 34h and the holder member 34g which are present outside, the support members 34c to 34f are disposed between the outer annular member 34h and the holder member 34g.

In order to utilize the annular focused light illumination optical system 29 to determine the In order to examine the size or shape characteristics of the lens, it is necessary to analyze the reflection angle or light intensity of the light reflected by the annular focused light 50a on the surface or the back surface of the lens to be inspected. Therefore, FIG. 7 shows an example in which the reflected light detecting portion 48 is provided in the annular focused light irradiation optical system 29.

For example, in order to measure the thickness of the lens to be inspected by the annular focused light irradiation optical system 29, it is necessary to measure the light intensity of the annular image formed by the annular focused light 50a on the front surface or the back surface of the lens to be inspected. As a specific structure, the beam splitter ( ) (half mirror ( 33) is disposed between the optical element 34 and the collimator lens 32 at an angle of approximately 45 degrees to the optical axis. Further, the reflected light detecting unit 48 is disposed at the tip end of the beam splitter 33. The reflected light detecting unit 48 is configured by a plurality of constituent members arranged in order of incidence of light from the annular image, that is, the reflected light detecting portion 48 is composed of an optical element (for example, a circular through hole) 39, a lens 40, and The CCD camera 41 disposed at the focal length f3 of the lens 40 is constituted. By analyzing the intensity distribution or the condensing position of the reflected ray input to the CCD camera 41, the angle between the reflected ray and the optical axis can be measured. Further, based on the angle between the measured reflected light and the optical axis, the shape characteristic of the lens to be inspected can be calculated, and the optical axis of the lens to be inspected can be adjusted as will be described later.

Further, the optical element 39 functions to block light transmitted through the small-diameter lens 34b as described above. Further, as shown in Fig. 8, the optical element 39 is configured such that the inner circular member 39c is disposed at the center of the outer annular member 39b, so that the optical member 39 is formed into a circular transmission hole 39a, and For the incident light, the annular light having the diameter of the predetermined range is transmitted, and the light other than the annular light having the diameter of the predetermined range is blocked. use. Further, since the transmission hole 39a is a space (space), the optical element 39 has a structure in which the outer annular member 39b and the inner circular member 39c are coupled by arranging the support members 39d to 39g.

[First Embodiment]

Next, as a first embodiment of the present invention, a measuring device for measuring the thickness of a lens to be inspected by the annular focused light irradiation optical system 29 described above will be described.

Fig. 9(A) is a view showing the configuration of an optical element thickness measuring apparatus according to the first embodiment of the present invention.

The first embodiment of the present invention is for observing a spotted light by causing focused light having a light intensity which is annular from the optical axis to be incident on an optical element to be inspected, and via an optical element having a transmission hole having a ring shape. A change in the light intensity of the image of the surface of the optical element and the back surface to determine the thickness of the optical element to be inspected. As the optical element to be inspected, for example, a lens having a curvature on the surface, a transparent substrate, a flat glass plate, or the like is also included. As a first embodiment of the present invention, a measuring device for measuring the thickness of a lens to be inspected whose curvature of the surface (r>0) is convex will be described.

Before the measurement method is described, first, two types of adjustments performed in the apparatus of the first embodiment of the present invention will be described. Further, Fig. 9(B) to Fig. 9(D) show the coordinate system of the entire configuration diagram of the first embodiment. The to-be-detected optical element holding portion 36 in which the optical element to be inspected is provided is provided on a rotary table 43 having a function of adjusting the x-axis, the y-axis, the z-axis, the swing angle θx, and the swing angle θy of the reference plane 300. Further, before measuring the thickness of the optical element 37 to be inspected, it is necessary to adjust the x-axis, the y-axis, the swing angle θx, and the swing angle θy of the rotating stage 43. The first adjustment is an adjustment in which the reference plane 300 on which the optical element holding portion 36 to be inspected is disposed on the rotating stage 43 is not necessarily perpendicular to the optical axis Z of the focused light, so adjustment is made (turns into vertical adjustment ( Vertical out )) so that the reference plane 300 on which the optical element holding portion 36 to be inspected is placed becomes perpendicular to the optical axis Z of the focused light. Because of this adjustment, a mirror that is not shown in the drawing is disposed on the reference plane 300 of the rotating platform 43 ( ). Then, the swing angle θx and the swing angle θy are adjusted so that the optical axis of the reflected light of the mirror coincides with the optical axis Z of the focused light. Such an adjustment is made when the optical element thickness measuring apparatus of the present invention is initially set. Further, when the optical element 37 to be inspected is placed at the optical element holding portion 36 to be inspected, the second adjustment is performed. After the second adjustment is made, the optical axis Z of the focused light becomes coincident with the optical axis of the optical element 37 to be inspected.

As shown in Fig. 9(A), when the first adjustment is performed, the optical system 30 in the apparatus of the first embodiment of the present invention emits the focused light 50a for measurement, and also emits parallel light as a rotating platform. 50b. When the parallel light 50b is emitted from the optical system 30, the mirror disposed on the rotating stage 43 but not shown in the drawing reflects the parallel light 50b. Then, the angle of the reflected light is measured by the automatic collimator portion 47 of the optical system 30. Next, the principle of measuring the angle of the reflected light will be described. First, if the reference plane 300 on which the optical element holding portion 36 to be inspected is placed on the rotating stage 43 and the optical axis of the sensor portion (the optical axis of the parallel light 50b that is irradiated on the mirror) are perpendicular, then the incident The direction of the parallel light 50b is reflected. Then, the reflected light reaches the beam splitter (half mirror) 33 along the path opposite to the incident path. Here, a portion of the reflected light is deflected toward the beam splitter (half mirror) 38 propagation. Therefore, the reflected light is deflected by the beam splitter (half mirror) 38, and is incident on the automatic collimator portion 47 composed of the optical element 44 having the transmission hole 44a, the lens 45, and the CCD camera 46. Also, Fig. 10 shows the shape of the optical element 44 of the auto-collimator portion 47.

Then, the reflected light is condensed on the light receiving surface of the CCD camera 46 connected to the processing unit 42 via a cable. When the reflected light is collected at a predetermined position on the light receiving surface, the processing unit 42 determines that the reference plane 300 is perpendicular to the optical axis Z of the focused light. However, if the processing unit 42 determines that there is no condensed light at the predetermined position, the sway angle θx and the swing angle θy of the rotating platform 43 are changed based on the condensing position (the digitized data transmitted from the CCD camera 41). The stage 43 is rotated so that the reflected light is irradiated at a prescribed position.

The second adjustment is performed when the optical element 37 to be inspected is placed at the optical element holding portion 36 to be inspected. Fig. 11 shows a state in which the focused light is reflected on the surface of the optical element to be inspected. In Fig. 11, the radius of curvature of the optical element 302 to be inspected is r, and the angle between the optical axis Zr of the reflected light 303a and 303b and the optical axis Z of the focused light is θ ₄ . In this case, the distance h between the measurement axis (the optical axis Z ' of the optical element 302 to be inspected) and the optical axis Z of the focused light can be expressed by h=r‧sin(θ ₄ /2), wherein θ ₄ is an angle between the optical axis Zr of the reflected lights 303a and 303b and the optical axis Z of the focused light, and r is the radius of curvature of the optical element 302 to be inspected. Here, the processing portion 42 can drive the x-axis and the y-axis of the rotating stage 43 so that the optical axis Z of the focused light coincides with the optical axis Z ' of the optical element 302 to be inspected. In other words, the processing unit 42 can adjust the distance h between the measurement axis (the optical axis Z ' of the optical element 302 to be inspected) and the optical axis Z of the focused light to 0 (h=0). In Fig. 11, the surface of the convex surface is placed toward the optical element 302 to be inspected of the optical system 30 at the optical element holding portion 304 to be inspected. Next, the principle in which the processing unit 42 causes the position of the uppermost point T of the convex surface of the optical element 302 to be inspected to exist on the optical axis of the optical system 30 (that is, on the optical axis Z of the focused light) will be described. First, as shown in Fig. 11, the focused lights 301a and 301b of the optical system 30 are used in the measurement. Then, when the focused lights 301a and 301b are irradiated on the optical element 302 to be inspected, they become parallel reflected light 303a and 303b and are reflected toward the lens 35. Here, if the position of the convex portion or the concave portion of the optical element 302 to be inspected exists on the optical axis Z of the focused light (reflection angle θ ₄ =0), the optical axis of the reflected light 303a and 303b and the light of the focused light Since the axis Z is identical, the processing unit 42 determines that the spot light is irradiated on a predetermined position of the light receiving surface of the CCD camera 46. Then, in the automatic collimator portion 47, the reflected light is imaged as spot light on the light receiving surface of the CCD camera 46 disposed at the focal length f5 of the lens 45. However, when the reflection angle of the optical axes of the reflected lights 303a and 303b with respect to the optical axis Z of the focused light is θ ₄ , if the reflection angle θ _{4 is} not 0 (θ ₄ ≠ 0), then It is detected that the spot light is not irradiated to a predetermined position on the light receiving surface of the CCD camera 46. Therefore, the rotary table 43 is adjusted to move in the x-axis direction and the y-axis direction so as to be adjustable so that the spot light coincides with the predetermined position. Further, the processing unit 42 is connected to the CCD camera 46 of the optical system 30 via a cable, and the spot light that is irradiated onto the light receiving surface of the CCD camera 46 is transmitted to the processing unit 42 as digitized data. Therefore, the processing unit 42 detects the spot light position based on the digitized data that has been transmitted, and then detects the difference between the direction and the distance between the measured spot light position and the predetermined position, and then rotates based on the difference. The stage 43 instructs to move the reference plane 300 on which the optical element holding portion 36 to be inspected is disposed in the x-axis direction and the y-axis direction, so that automatic adjustment can be performed to make the spot light position coincide with the predetermined position. The reflection angle θ ₄ corresponds to the position of the spot light (concentration point) on the light receiving surface of the CCD camera 46, and the processing unit 42 can calculate the reflection angle θ ₄ based on the position. Further, at this time, the processing unit may adopt a configuration in which the processing unit 42 calculates the light intensity and the angle θ _{4 of the} incident light based on the image obtained by the CCD cameras 41 and 46, and outputs and displays it to, for example, the processing unit. 42 monitors on the PC.

Further, although it is shown that the optical element 37 to be inspected toward the optical system 30 is disposed at the optical element holding portion 36 to be inspected, the concave optical element is disposed so that the concave surface faces the optical system 30. When the optical element holding portion 36 is inspected, the position of the lowermost portion of the concave surface of the concave optical element is adjusted to be present on the optical axis of the optical system 30 (that is, on the optical axis Z of the focused light). In this case, the adjustment can be made in the same manner as described above.

Next, an effective method will be described with reference to Figs. 12 to 14. The effective method is to use an annular focused light 310 to produce an image produced on a surface of a thin optical element (for example, a lens having a thickness of 200 μm or less) and an image generated on the back surface of the thin optical element. separate. Figs. 12 and 13 show the image generated by the ring-shaped focused light 310 irradiated on the optical element 37 to be inspected provided at the optical element holding portion 36 to be inspected on the surface of the optical element 311 to be inspected. An image generated on the back surface of the optical element 311 to be inspected. Also, Fig. 14 shows an image formed on the light receiving surface of the CCD camera 41.

In the prior art, when the focused light 24 from the sensor portion 20 is irradiated onto the optical element 21 to be inspected and the thickness of the optical element is measured, since the condensed spot 202 is present on the surface 203a of the optical element 203 to be inspected The image 204a imaged on the light receiving element of the sensor unit 20, which is not shown in the drawing, is overlapped with the image 204b on the back side or the image 204b on the back surface. Therefore, it is difficult to image the image 204a and the back surface as shown in FIG. The problem of being separated like 204b.

Therefore, in the first embodiment of the present invention, as shown in Figs. 12 and 13, the above problem is solved by using a light beam (e.g., a ring shape) that covers the center of the focused light. Fig. 12 shows that the ring-shaped focused light 310 is incident on the optical element 311 to be inspected, on the interface between the surface of the optical element 311 to be inspected and the air, and the interface between the back surface of the optical element 311 and the air. The appearance of the two images produced by the reflected light. Explain these images. First, in the case where the condensed spot 312 exists on the surface 311a, the image of the surface 311a becomes a dot, and the back surface image 313 having a small ring shape is formed at the interface between the back surface and the air, and is reflected by the interface between the back surface 311b and the air. The focused light forms a large annular surface image 314 on the surface 311a that is larger than the back surface image 313. By doing so, the annular back side image 313 does not overlap with the annular surface image 314, so they can be separated. Further, as shown in Fig. 13, when the condensed spot 322 exists on the back surface 311b, the image of the back surface 311b becomes a dot and is reflected, and the small annular image 323 is formed on the surface 311a by the surface 311a. The focused light reflected at the interface with the air forms a large annular image 324 larger than the annular image 323 of the surface 311a on the back surface 311b. By doing so, the annular image 323 does not overlap with the annular image 324, so they can be separated. In this way, by moving the rotary table 43 in the z-axis direction, not only can it be efficiently performed When the light-converging point 312 is present on the surface 311a, the annular surface image 314 formed on the surface 311a and the annular back surface image 313 are separated, and the light-converging point 322 can be efficiently formed on the back surface 311b when it exists on the back surface 311b. The annular back side image 324 is separated from the ring shaped image 323. Therefore, in the graph showing the change in the light intensity with respect to the z-axis, the two maximum values (peaks) of the light intensities of the surface image 313 and the back surface image 324 can be detected with high precision. As a result, the thickness t of the optical element 37 to be inspected can be accurately calculated based on the difference in the z-axis corresponding to the two light intensities.

Here, the state of imaging detected on the light receiving surface of the CCD camera 41 will be described. Fig. 14(A) shows an annular surface image 402a in which the surface image 314 of Fig. 12 is imaged on the light receiving surface of the CCD camera 41. As described above, since the optical element 34 has the transmission hole 34a which is annular, the area in which the parallel light is transmitted through the transmission hole 34a and irradiated on the light receiving surface can be displayed as the outer side indicated by the broken line in Fig. 14. The virtual line 401a is the same as the passing area 401c sandwiched by the inner virtual line 401b indicated by a broken line in Fig. 14. By doing so, it is possible to pass the light from the surface image 314 through the annular transmission hole 34a of the optical element 34 so as to be able to be affected by the light intensity of other images and to be easily utilized by the CCD camera 41. The light intensity of the surface image 314 is detected. Similarly, Fig. 14(B) shows the annular back image 402b on which the back surface image 324 of Fig. 13 is imaged on the light receiving surface of the CCD camera 41. Similarly, it is possible to pass light passing from the back surface image 324 through the annular transmission hole 34a of the optical element 34 so as to be easily detected by the CCD camera 41 without being affected by the light intensity of other images. The light intensity of the back image 324 is shown. In this way, if the design is ring-shaped transmission The inner diameter and the outer shape of the hole 34a are such that the annular focused light 314 and the condensed spot 322 which are formed after the condensed spot 312 is reflected on the surface 311a and reflected at the interface of the back surface 311b and the air are present on the back surface 311b. When both of the annular focused lights 324 formed on the interface with the air are imaged in the range of the passing region 410c, the light intensity and the focused spot 322 when the focused spot 312 exists on the surface 311a can be effectively detected. The light intensity at the time of the back surface 311b, and the detected light intensity is a maximum value (peak value) of the light intensity change with respect to the z-axis. Conversely, in the case where the condensed spot exists outside the surface 311a and the back surface 311b, as shown in Fig. 15(A), the annular surface image 404a imaged by the light from the surface image and the image from the back side The circular back image 404b imaged by the light rays is not present in the passing region 401c, so the annular surface imaging 404a and the annular back imaging 404b do not contribute to the calculation of the light intensity, so that the processing portion 42 can be effectively reduced. Calculated light intensity. In particular, when the condensed spot exists at a position near the surface depth t/2 of the optical element 37 to be inspected (here, t is the thickness of the optical element 37 to be inspected), as shown in Fig. 15(B), If the inner diameter and outer shape of the transmission hole 34 are designed so that both the annular surface image 404c and the annular back surface image 404d are completely obscured, the maximum and minimum values of the light intensity variation with respect to the z-axis can be effectively detected. The z-axis position. In addition, since the optical element 34 blocks the images 403a and 403b of the condensed spot, the images 403a and 403b of the condensed spot do not contribute to the light intensity.

Fig. 4 and Fig. 16 are graphs showing actual measurement results of the optical element 37 to be inspected (lens having a thickness of 200 μm). As described above, Fig. 4 is a graph showing the light intensity with respect to the z-axis obtained when the measurement is performed using a light beam having a circular light beam having a circular light beam and a circular beam. On the other hand, Fig. 16 is a graph showing the light intensity with respect to the z-axis obtained when the measurement is performed using the light beam of the ring-shaped focused light according to the first embodiment of the present invention. The difference between the maximum value and the minimum value of the light intensity read from the graph of Fig. 4 is "11". On the other hand, the maximum value and the minimum value of the light intensity read from the graph of Fig. 16 are The difference between the two is "70". As a result, it is possible to effectively separate the image generated on the surface 311a of the optical element 37 to be inspected from the image generated on the back surface 311b of the optical element 37 to be inspected, and to enlarge and measure the origin from the z-axis. The light intensity of the image on the surface and back of the optical element is varied. As described above, the processing unit 42 detects the maximum value (peak value) of the two light intensities based on the measurement data, and calculates the difference between the z-axis of the two maximum values and uses it as the measured value d.

However, the measured value d calculated by the optical system 30 and the processing unit 42 cannot be directly regarded as the thickness t of the optical element 37 to be inspected. As shown in Fig. 17, the reason is because the focused lights 501a and 501b are refracted on the surface 502a of the optical element 502 to be inspected, that is, the focused lights 501a and 501b are refracted at the interface of the optical element 502 to be inspected with air. . The measurement of the position of the point A as the condensed point of the surface 502a is not affected by the refraction. However, the measurement of the position of the point B as the light collecting point of the back surface 502b is affected by the refraction of the focused light. For example, in the case where the refractive index n of the optical element 502 to be inspected is not considered, there arises a problem that it is assumed that the condensed spot of the back surface 502b exists at the point E where the focused lights 501a and 501b intersect, and the measured value is calculated. The problem with d. Therefore, in order to calculate the correct thickness t of the optical element 37 to be inspected, it is necessary to find the condensing angle θ ₁ which can be based on the above-described measured value d, the focused lights 501a and 501b, the radius of curvature r of the surface 502a of the optical element 502 to be inspected, and The calculation formula of the thickness t of the optical element to be inspected 502 is calculated from the refractive index n of the material of the optical element 502 to be inspected.

Here, a method for obtaining a calculation formula for calculating the thickness t of the optical element (the convex lens) 502 to be inspected in the first embodiment of the present invention will be described. Further, the surface of the optical element to the subject a radius of curvature r (r> 0) 502, the refractive index n and the focused light beam collection angle θ 501b and 501a ₁ are known as a premise.

First, Fig. 17 is a view showing the spot light 501a and 501b incident on the convex shape of the optical element 502 to be inspected, and the point C and the point F located in the surface 502a of the optical element 502 to be inspected are refracted, and the point in the back surface 502b. A picture of the way that B is concentrated.

Point A is the intersection of surface 502a and the optical axis of the focused light; point B is the focused spot of back surface 502b; point C and point F are the positions where focused light 501a and 501b are refracted at surface 502a; point D is the curvature of surface 502a Center; point E is the intersection of surface 502a with the optical axis of the focused light that does not account for refraction. Also, the length of the line segment AE is the measured value d; the length of the line segment AB corresponds to the thickness t of the optical element. Further, regarding the angle of the focused light, the condensing angle is set to θ _{1 based on the} optical axis Z of the focused light; the angle between the line segment BC and the optical axis Z is set to θ ₂ ; and the connection is made as the focused light 501a and 501b. The angle C of the intersection C of the surface 502a and the line CD of the point D which is the center of curvature of the surface 502a and the optical axis Z are connected as the point F of the intersection of the focused light 501a and 501b with the surface 502a and the center of curvature of the surface 502a. The angle between the line segment FD of the point D and the optical axis Z is set to θ ₃ . First, the above-described set value is used, and an equation for expressing a straight line equation (i.e., a straight line equation for representing the line segment CE) and a circle for indicating the surface 502a of the optical element 502 to be inspected is used, The x coordinate of the point C, that is, the distance e between the optical axis Z of the focused lights 501a and 501b and the point C is obtained. Next, based on the distance e which is the x coordinate of the point C, θ ₃ , f which is the y coordinate of the point C and the point F, and Δ (= rf) are obtained. Then, based on θ ₂ obtained by Snell's law (refraction law) and the x coordinate e of the point C, g which is the distance between the point C and the back surface 502b of the optical element to be inspected 502 is obtained. Using the above results, the thickness t (= g + Δ) of the optical element to be inspected 502 is calculated.

Specifically, by setting the point D which is the center of curvature of the surface of the optical element as the origin of the coordinates, the line segment CE can be expressed by Equation 1 which is a straight line equation having the slope a and the intercept b.

[Formula 1] y = ax + b

Also, the slope a and the intercept b can be expressed by Equations 2 and 3, respectively.

[Formula 3] b = r - d

Then, by setting the point D as the origin of the coordinates, the surface 502a of the optical element 502 to be inspected can be represented by Equation 4 which is an equation of a circle.

Based on Equations 1 and 4, the equation for calculating the x coordinate e of the point C can be expressed by Equation 5 (in Equation 5, x represents the x coordinate e of the point C).

The distance e between the point C and the optical axis Z of the focused lights 501a and 501b can be found based on Equation 6.

Here, the intersection of a straight line passing through the point C and the point E and a circle having the point D as a center and r as a radius will be described. As shown in Fig. 17, in the case where the surface 502a of the optical element to be inspected 502 is convex (r > 0), the point C is taken as a straight line passing through the point C and the point E, and the point D is the center of the circle and the radius is r. Round intersection, and The sign takes a positive (+) value. Further, as shown in Fig. 18, in the case where the surface 502a of the optical element to be inspected 502 is concave (r < 0), the point C ' is taken as a straight line passing through the point C and the point E and is centered on the point D. The intersection of a circle with radius r, and The sign takes a negative (-) value.

Next, as described below, the distance e between the utilization point C and the optical axis Z of the focused lights 501a and 501b, the measured value d, the refractive index n of the material of the optical element, the surface curvature radius r, and the focused light are concentrated. The principle that the angle θ ₁ can calculate the thickness t of the optical element 502 to be inspected will be described.

As shown in Fig. 17, by using the distance e and the radius of curvature r of the surface, the line segment as the point C which is the intersection of the focused lights 501a and 501b and the surface 502a and the point D which is the center of curvature of the surface 502a can be expressed by the equation 7. θ ₃ of the angle between the CD and the optical axis Z.

[Formula 7]

Further, with θ ₃ and the surface curvature radius r, f which is the y coordinate of the point C can be expressed by Equation 8. Further, the distance Δ from the y coordinate of the point C to the point A of the uppermost portion of the surface 502a of the optical element to be inspected 502 can be expressed by the equation 9.

[Equation 8] f = r cos θ ₃

[Equation 9] △ = r - f

Then, using Snell's law, the incident angle (θ _{1 -} θ ₃ ), the refraction angle (θ _{2 -} θ ₃ ) of the surface 502a of the optical element to be inspected 502, and the refraction of the optical element 502 to be inspected can be expressed by Equation 10 The relationship between the rates n. Further, by modifying the formula 10, the formula 11 can be obtained.

[Formula 10] sin( θ ₁ - θ ₃ )= n sin( θ ₂ - θ ₃ )

Further, g which is the distance from the point C to the back surface 502b of the optical element to be inspected 502 can be expressed by the formula 12.

The thickness t of the lens can be expressed by Equation 13. Further, the thickness t of the lens can also be expressed by Equation 14 using Equations 9 to 13.

[Equation 13] t = g + △

By doing as described above, in the first embodiment of the present invention, the refractive index n which can be based on the measured value d, the material of the optical element to be inspected, the surface curvature radius r, and the condensing angle θ ₁ using the focused light are found. The calculated distance e is used to calculate a formula for calculating the thickness t of the lens of the optical element to be inspected.

Here, the procedure for measuring the thickness t of the optical element 37 to be inspected in the first embodiment of the present invention will be described. First, the optical axis of the optical system 30 (i.e., the focused optical axis Z) and the reference plane 300 of the optical element holding portion 36 to be inspected are vertically adjusted. As described above, the angle between the optical axis of the optical system 30 and the reference plane 300 of the optical element holding portion is measured, and the adjustment is performed by the rotary stage 43.

Next, the position of the optical element 37 to be inspected is adjusted by adjusting the x-axis and the y-axis of the rotary stage 43 to make the optical axis of the optical system 30 and the optical axis of the optical element 37 to be inspected coincide in the xy plane. Specifically, the optical element 37 to be inspected is disposed in the optical element holding portion 36 to be inspected, and when the focused light is irradiated onto the optical element 37 to be inspected, the focused light becomes parallel rays on the surface of the optical element 37 to be inspected and is reflected. Thereafter, it passes through the optical system 30, then reaches the automatic collimator portion 47, and is imaged on the light receiving surface of the CCD camera 46. By adjusting the x-axis and y of the rotary table 43 on which the optical element holding portion 36 to be inspected is disposed The axis adjusts the reflection angle of the parallel rays reflected by the optical element 37 to be inspected so that the spot light on the light receiving surface of the CCD camera 46 that has been imaged on the autocollimator portion 47 is at a prescribed position, and the point is made The area of light becomes the smallest.

Then, by moving the rotary stage 43 in the z-axis direction to move the optical element 37 to be inspected along the z-axis direction, annular imaging on the light-receiving surface of the CCD camera 41 is detected, and then the detected annular image is imaged. The data is converted into digitized data and transmitted to the processing unit 42. The processing unit 42 stores measurement data obtained by correlating the value of the z-axis with the light intensity calculated based on the digitized data. The processing unit 42 detects the maximum value (peak value) of the two light intensities based on the measurement data, and then calculates the difference between the z-axis of the two maximum values and uses it as the measured value d. Finally, the processing unit 42 calculates the lens of the optical element to be inspected based on the measured value d, the refractive index n of the material of the optical element to be inspected, the surface curvature radius r, and the distance e calculated by the collecting angle θ ₁ of the focused light. Thickness t.

[Second embodiment]

Next, a second embodiment of the present invention will be described. In the second embodiment, in order to replace a bundle of focused light, a plurality of beams (plural beams) are arranged, for example, four beams as shown in Fig. 19 are arranged so as to pass through a virtual ring. The light is focused (i.e., such that it passes through a region sandwiched by the outer circumference 335a of the virtual annular focused light and the inner circumference 335b of the virtual annular focused light). The four beams branched from the condensing point 332 form an image composed of four back images 333a, 333b, 333c, and 333d. Then, the images composed of the four back images 333a, 333b, 333c, and 333d are respectively formed on the surface 311a, and an image composed of the four surface images 334a, 334b, 334c, and 334d is formed. Although in Fig. 19, four focused lights (four focused lights) 331a, 331b, 331c, and 331d, but in the second embodiment of the present invention, the number of light beams (the number of light beams) is not limited to four (four beams), and any number (number) of light beams may be used. Further, the respective light beams arranged in the region sandwiched by the outer circumference 335a of the virtual annular focused light and the inner circumference 335b of the virtual annular focused light are specifically arranged as shown in Fig. 19, respectively. The origin at which the x-axis and the y-axis intersect is the center of the square. Further, in Fig. 19, each of the light beams is disposed at each vertex of a square centered on the origin where the x-axis and the y-axis intersect as shown in Fig. 19, but the second embodiment of the present invention The arrangement of the respective light beams is not limited to the configuration as shown in Fig. 19, and the respective light beams may be respectively disposed to be sandwiched by the outer circumference 335a of the virtual annular focused light and the inner circumference 335b of the virtual annular focused light. Anywhere in the area. Further, in the second embodiment of the present invention, the light amount of each light beam can be distributed at an arbitrary distribution ratio, and the light intensity of each light beam can be distributed at an arbitrary ratio. Further, in the second embodiment of the present invention, the optical element 61 having four circular through holes as shown in Fig. 20(A) is used so that the four beams as shown in Fig. 19 are used. (four beams) pass. Further, in the second embodiment of the present invention, the optical element 62 having four circular through holes as shown in Fig. 20(B) is used. As shown in Fig. 20(A), the through holes 61c to 61f are arranged at respective vertices of a square centered on the optical element 61. Further, as shown in Fig. 20(B), the through holes 62b to 62e are disposed at respective vertices of a square centered on the optical element 62. Further, in the second embodiment of the present invention, the position and diameter of each of the above-described through holes may be designed to correspond to the number and arrangement of the light beams for measurement.

[Third embodiment]

Next, a third embodiment of the present invention will be described. In the third embodiment, a method for calculating the thickness t of the optical element 512 to be inspected when the optical element 512 to be inspected is a flat plate (curvature radius r = ∞) will be described. Fig. 21 is a view showing a state in which the focused light 501a and 501b are incident on the surface and the back surface of the optical element to be inspected 512, and the surface 512a is refracted, and then collected on the back surface 512b. Regarding the angle of the focused light, the condensing angle is set to θ ₁ based on the optical axis Z of the focused light, and the angle at which the focused light is refracted on the surface 522a of the flat plate is θ ₆ .

Using Snell's law, the relationship between θ ₁ and θ ₆ can be expressed by Equation 15. Further, by deforming the equation 15, it is possible to express θ ₆ by the equation 16.

The x coordinate of the intersection of the focused lights 501a and 501b with the surface 522a, that is, the distance between the optical axis Z of the focused lights 501a and 501b and the intersection is set to i, and the focused spot and surface of the focused light that will not be considered When the distance between 522a is set to d, Equation 17 can be used to represent θ ₁ .

[Equation 15] sin θ ₁ = n sin θ ₆

[Equation 17] i = d tan θ ₁

Then, using Equations 17 and 18, the thickness t of the flat plate can be expressed by Equation 19.

[Equation 18]

As described above, in the optical element thickness measuring device (optical element characteristic measuring device) of the present invention, it is possible to calculate based on the measured value d, the refractive index n of the material of the optical element, and the condensing angle θ _{1 of the} focused light. The thickness t of the plate.

Unlike the above example, here, the measured value d is determined by the optical element 522 having the refractive index n and the known thickness t and the surface and the back surface are parallel to each other in order to determine the optical element thickness measuring device of the present invention. The method of the concentration angle θ ₁ of the focused light of the inherent set value will be described. As the optical element to be inspected 522, for example, a glass plate can be used.

Equations 20 and 21 can be used to represent sin θ ₁ and sin θ _{6 , respectively} . Further, when the formulas 20 and 21 are substituted into the above formula 15, the relationship shown in the formula 22 can be obtained.

Then, by deforming the equation 22, i can be expressed by the equation 23. Further, when Equation 17 is used, θ ₁ can be expressed by Equation 24.

As described above, in the optical element thickness measuring device (optical element characteristic measuring device) of the present invention, the focused light can be calculated based on the measured value d, the refractive index n of the material of the optical element, and the known thickness t of the optical element. Convergence angle θ ₁ . Before measuring the thickness of the optical element by the optical element thickness measuring apparatus of the present invention, it is necessary to correct the optical element thickness measuring apparatus of the present invention. In order to correct the optical element thickness measuring apparatus of the present invention, it is necessary to measure the condensing angle θ ₁ of the focused light which is a set value unique to the optical element thickness measuring apparatus of the present invention. Based on the refractive index n of the material of the optical element, the known thickness t of the optical element, and the measured value d, and using Equation 24, the condensing angle θ ₁ of the focused light can be calculated.

[Fourth embodiment]

The lens surface deviation amount measuring device (optical element characteristic measuring device) of the present invention is a device that simultaneously emits focused light having a ring-shaped light intensity distribution from the optical axis of the reflected light sensor portion and is A parallel ray that is irradiated near the center of the lens to be inspected, and the position of the lens to be inspected is adjusted so that the lens central axis of the lens to be inspected (the normal of the first surface of the lens to be inspected) and the optical axis of the reflected light sensor portion become uniform , measuring the light transmitted through the lens under test The position of the condensed spot is such that the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

Fig. 22 is a view for explaining the definition of the amount of surface deviation of the lens to be inspected measured by the lens surface deviation amount measuring device according to the fourth embodiment of the present invention. Here, the definition of the amount of surface deviation of the lens to be inspected will be described with reference to Fig. 22 . As shown in Fig. 22, in the lens surface deviation amount measuring device of the present invention, the inspection lens 20 is provided at the lens holder 112 to be inspected. Then, the upper surface of the lens holding portion 111 to be inspected is referred to as a reference plane LS. Next, as shown in FIG. 22, the center of the core (the center point of the first surface) CN1 disposed on the first surface is located at the normal line LN1 of the first surface 20a of the lens to be inspected perpendicular to the reference plane LS, and The center of the two sides (the center point of the second surface) CN2 is located on the normal line LN2 of the second surface 110b of the lens to be inspected perpendicular to the reference plane LS. Also, there is a structure in which the detected lens holding portion 111 for holding the lens holder 22 is supported by the lens holder holding platform portion 113 in order to secure the reference plane LS.

In such a configuration, the distance between the normal of the first surface (surface) 110a of the examined lens perpendicular to the reference plane LS and the normal of the second surface (back surface) 110b of the detected lens perpendicular to the reference plane LS Set to the surface deviation amount Δ ₂ . In the embodiment of the present invention, the normal line LN1 of the first surface 110a of the lens to be inspected is defined as the lens central axis of the lens to be inspected. This definition is used below for explanation.

As shown in Fig. 23, the lens surface deviation amount measuring device 120 of the present invention includes a lens holder 121 to be inspected, a lens holder holding mechanism platform portion 122, a reflected light sensor portion 123, a transmitted light sensor portion 124, and a transmitted light sensor. Department holding mechanism platform unit 124c, data processing unit 125, and monitor 126, The detected lens holder 121 is used to set the detected lens 121a; the lens holder holding mechanism platform portion 122 is for holding the detected lens holder 121, and fixing the detected lens holder 121 to the X-axis, A direction in which one of the Y axis and the Z axis moves while being rotatable (tilted) along the X axis or the Y axis; the reflected light sensor portion 123 has a function for measuring that the light beam from the light source 123a is reflected by the detected lens 121a The reflected light sensor unit automatic collimator 123b that has an angle between the light and the optical axis; the transmitted light sensor unit 124 has a transmitted light sensor unit automatic collimator 124a and light for measuring the angle between the light transmitted through the detected lens 121a and the optical axis. The sensor portion 124b; the transmitted light sensor portion holding mechanism platform portion 124c is for fixing the transmitted light sensor portion 124 to be movable in one of the X-axis, the Y-axis, and the Z-axis, and may also be along the X-axis or the Y-axis. The rotating (tilted) platform; the data processing unit 125 calculates the detected lens 121a based on the outputs of the reflected light sensor portion autocollimator 123b, the transmitted light sensor portion autocollimator 124a, and the photosensor portion 124b. Surface deviation amount; the monitor 126 for displaying an amount of deviation from the plane of the arithmetic data processing unit 125.

Fig. 24 is a view showing a detailed configuration of the lens surface deviation amount measuring device 130. Next, the lens surface deviation amount measuring device 130 will be described with reference to the configuration diagram of Fig. 24.

The lens surface deviation amount measuring device 130 includes a detected portion 130a, a reflected light sensor portion 130b, a transmitted light sensor portion 130c, a transmitted light sensor portion holding mechanism platform portion 139, a data processing portion 130d, and a display 130e, wherein the detected portion 130a There is a lens holder 131b for holding the lens to be fixed 131a, and has a reference plane and can move in one of the X-axis, the Y-axis, and the Z-axis while also being along the X-axis or Y Axis rotation The lens holder holding mechanism platform portion 131c; the reflected light sensor portion 130b is for irradiating the annular focused light to the inspection lens 131a, and has a reflection light for measuring the first surface from the lens to be inspected from the lens central axis The automatic collimator function of the included angle; the transmitted light sensor unit 130c has a light for detecting the transmitted light that is transmitted through the inspection lens 131a by the parallel light that is simultaneously irradiated with the annular focused light from the reflected light sensor unit 130b. The function of the spot position and the automatic collimator function for measuring the angle between the transmitted light and the central axis of the lens; the transmitted light sensor portion holding mechanism platform portion 139 for holding the transmitted light sensor portion 130c, and may be oriented toward the X-axis, Y The movement of one of the axis and the Z axis is also possible to rotate along the X axis or the Y axis; the data processing unit 130d has a function of calculating the amount of surface deviation based on the spot position data by the measurement processing of each of the above-described automatic collimators And the function of calculating the amount of surface deviation based on the angle between the transmitted light and the central axis of the lens. Further, the lens holder holding mechanism platform portion 131c is provided with a lens holding portion (not shown) having a reference plane. As the lens holder holding mechanism platform portion 131c, a rotating platform can be used.

Further, the light source unit 132 is composed of a light source (for example, a laser diode) 132a and a lens (focus distance f2) 132b for emitting parallel rays. Then, the optical element 133 for converting the light beam irradiated from the light source unit 132 into the ring light and the light beam is disposed in the reflected light sensor unit 130b. Next, a lens (focus distance f4) 134 for converting the ring-shaped light into focused light and converting the light collected at the point C into parallel rays is disposed, and is irradiated onto the to-be-detected lens 131a. The optical element (pinhole) is placed immediately before the light reflected by the inspection lens 131a is incident on the reflected light sensor section automatic collimator 136. Also, Fig. 25 (A) and Fig. 25 (B) show the shapes of the optical elements 133 and 135, respectively. shape. As shown in Fig. 25(A), the optical element 133 has a structure in which an inner annular member 133g is disposed at the center of the outer annular member 133h so as to form a circular transmission hole 133a, and has a light for incident light. The annular light of the diameter of the specified range is transmitted. Further, the small-diameter lens 133b having the focal length f5 is disposed near the center of the optical element 133, and has a function of converting parallel rays into focused light. Further, as the holder for supporting the small-diameter lens 133b, the annular member 133g is disposed. Further, since the bracket member 133g and the bracket member 133h become the transmission holes 133a, that is, become spaces, the support members 133c to 133f are disposed. As shown in Fig. 25(B), the optical element 135 has a structure in which a transmission hole 135a for light passage is disposed in the center of the outer holder 135b.

First, in order to adjust the reference plane LS of the lens holder 131b to be perpendicular to the optical axis of the reflected light sensor portion 130b, a plane mirror (not shown) is disposed on the lens holder 131b to be inspected. The reference plane is on the LS. Next, the parallel light rays emitted from the reflected light sensor unit 130b are reflected, and the reflected light sensor portion automatic collimator including the lens (focus distance f7) 136a and the reflected light sensor portion light receiving device 136b in the reflected light sensor portion 130b is used. 136 to determine the angle of the reflected light. Then, the angle is adjusted by the lens holder holding mechanism platform portion 131c to be 0 degree with respect to the optical axis of the reflected light sensor portion 130b.

Next, the transmitted light sensor unit automatic collimator 138 and the transmitted light sensor unit optical system 137 (light collecting point position detecting light receiving element) of the transmitted light sensor unit 130c are adjusted by the optical axis of the reflected light sensor unit 130b. The adjustment of the origin is performed by the position on the XY plane of the transmitted light sensor unit 130c (original point ).

In the initial setting of the lens surface deviation amount measuring device according to the fourth embodiment of the present invention, a plano-convex lens is used as the adjustment lens 142. Fig. 26 is a view showing the optical path of the annular focused light 145a, the annular reflected light 145b, and the parallel rays passing through the vicinity of the central axis of the lens in the initial setting of the lens surface deviation amount measuring apparatus according to the fourth embodiment of the present invention. 146 look. Further, the adjustment lens 142 is placed on the subject lens holder 143 so that the convex surface of the adjustment lens 142 faces the side of the reflected light sensor portion 141a. Then, the transmitted light sensor portion automatic collimator (not shown) and the transmitted light sensor portion light receiving device in the transmitted light sensor portion 141b are observed by the data processing unit 141c while being observed on the monitor 141d (not In the image obtained by processing the transmitted image data, the transmitted light sensor portion holding mechanism platform portion 144 is adjusted along the Z-axis direction so as to minimize the area of the focused spot image. Since the adjustment lens 142 is a plano-convex lens, the condensed spot of the transmitted ray does exist on the central axis of the lens, so that the transmitted light sensor section automatic collimator (not shown) and the photosensor section can be used. The position on the light receiving element shown in the drawing is set as the origin and stored in the data processing unit 141c, and the XY position which becomes the origin of the reflected light sensor portion 141a and the transmitted light sensor portion 141b can be fixed. Through the above process, the lens central axis (of the adjustment lens 142) and the optical axis of the reflected light sensor portion 141a can be made uniform, and the optical path 146 of the parallel light ray can be irradiated near the lens center (of the adjustment lens 142).

As described above, the optical axis of the reflected light sensor portion 130b and the reference plane LS of the detected lens holding portion (not shown) for holding the detected lens holder 131b are vertically adjusted. . Also, a plane mirror is disposed at the lens holder 131b to be inspected, and the light is transmitted from the reflection The parallel rays that are illuminated by the sensor portion 130b are reflected. Then, the angle between the optical axis and the optical axis is measured by the reflected light sensor unit automatic collimator 136 of the reflected light sensor unit 130b. Based on the measured angle with the optical axis, adjustment is made so that the angle for holding the detected lens holding portion (not shown in the drawing) of the lens holder 131b to be changed becomes 0 for the optical axis of the reflected light sensor portion 130b. degree. Further, the above-described subject lens holding portion holds the subject lens holder 131b, and forms the reference plane LS in the same manner as the subject lens holding unit 111 described above.

Next, the optical axis alignment (optical axis alignment) for measuring the amount of surface deviation of the lens 31a to be inspected by the lens surface deviation amount measuring device 130 of the present invention is performed. The position adjustment of the lens holder holding portion 131b in the Z-axis direction is briefly described. The angle of the reflected light from the detected lens 131a is measured by the reflected light sensor portion automatic collimator 136 of the reflected light sensor portion 130b, and the lens holder holding mechanism platform portion 131c for holding the detected lens holding portion 131b is adjusted. The position in the XY plane is such that the measurement angle becomes 0 degrees, so that the optical axis of the reflected light sensor portion 130b (the optical axis of the annular focused light irradiated from the reflected light sensor portion 130b) and the lens central axis can be changed. Consistent.

Here, in the fourth embodiment of the present invention, the optical axis of the reflected ray of the lens to be inspected becomes a parallel ray that does not coincide with the central axis of the first surface of the lens to be inspected, and is reflected. Figure 27 shows the state that has not been adjusted. Further, Fig. 28 shows a state in which the optical axis of the reflected ray of the detected lens becomes parallel rays which are coincident with the central axis of the first surface of the lens to be inspected, and is reflected, that is, Fig. 28 shows that the optical axis has been adjusted. status.

First, the detected lens 150 is mounted on the lens holder 151 to be inspected. (Specific lens holder for the lens to be inspected), and it is placed on the reference plane LS of the detected lens holding portion (not shown).

Next, the subject lens holder 131b is adjusted in the Z-axis direction so that the condensed spot position FP1 condensed by the ring-shaped focused lights 152a and 152b irradiated from the reflected light sensor portion 130b is moved to the first lens to be inspected. The intermediate position of the surface 150a and the center of the center CN1 of the first surface 150a of the lens to be inspected. As a result, the reflected light rays 152c and 152d from the first surface 150a of the lens to be inspected become parallel rays, and are returned to the reflected light sensor portion 130b to be incident. Then, the parallel ray is reflected by 90 degrees at the half mirror 32c, and is incident on the reflected light sensor portion automatic collimator 136 of the reflected light sensor portion 130b. The reflected light sensor portion automatic collimator 136 can measure the angle θ ₀ between the parallel ray and the lens central axis (the normal to the first surface of the lens to be inspected). Then, based on the included angle θ ₀ , the in-plane XY deviation amount of the detected lens holder 131b of the focused light spot position FP1 where the focused light is concentrated and the lens central axis (the normal line of the first surface of the detected lens) LZ can be calculated. . Based on the XY deviation amount, the lens holder holding mechanism platform portion 131c is moved in the XY plane to adjust the optical axis of the lens central axis and the lens surface deviation amount measuring device (that is, the light of the annular focused light) The axis) becomes consistent. By this adjustment, the parallel rays which are simultaneously irradiated from the reflected light sensor portion 130b are irradiated in parallel to the central axis of the lens, and are also irradiated near the center of the lens 31a to be inspected.

Further, since the optical axis of the parallel ray that is simultaneously emitted from the reflected light sensor unit 130b and the annular focused light is adjusted to match the optical axis of the annular focused light, the lens of the fourth embodiment of the present invention The surface deviation amount measuring device 130 passes the parallel light that is emitted from the reflected light sensor portion 130b. The optical axis of the line is set as the reference axis, and the detected lens holder holding portion 131b and the transmission are adjusted by adjusting the respective plate mechanisms (i.e., the lens holder holding mechanism platform portion 131c and the transmitted light sensor portion holding mechanism platform portion 139). The optical axis of the photosensor portion 130c makes it possible to align the optical axis of the entire lens deviation amount measuring device.

First, the lens holder holding mechanism platform portion 131c is moved in the Z-axis direction so that the focused spot FP1 of the annular focused light (i.e., convergent light) emitted from the reflected light sensor portion 130b is positioned first in the lens to be inspected. The center of the face CN1 and the first face 150a of the lens to be inspected. In this state, the lens holder holding mechanism platform portion 131c is not adjusted in the XY plane, as shown in Fig. 27, the optical axis LF of the focused lights 152a and 152b and the central axis of the lens (the first surface of the lens to be inspected) The line LZ is offset by the distance (XY deviation amount) L ₁ , and the reflected rays 152c and 152d are inclined with respect to the central axis LZ of the lens. Here, adjustment is made by moving the lens holder holding mechanism platform portion 131c in the XY plane, so that the reflected light rays 152c and 152d from the first surface 150a of the lens to be inspected become the central axis of the lens (the first lens to be inspected) The normal of the face) LZ parallel rays. For example, when the radius of curvature of the first surface of the lens to be inspected is r ₁ , the distance (XY deviation amount) L ₁ can be expressed by Equation 25.

That is to say, the angle θ ₀ is measured by an automatic collimator that reflects the light sensor unit. Then, by adjusting the lens holder holding mechanism platform portion 131c of the lens holder 131b to change the angle θ ₀ to 0 degrees, it is possible to adjust so that the optical axis of the reflected light sensor portion 130b and the lens central axis LZ become Consistent, that is, it can be adjusted such that the distance L ₁ becomes 0 (L ₁ =0). By such adjustment, as shown in Fig. 28, the optical axes of the parallel rays 162c and 162d obtained by reflecting the focused lights 162a and 162b on the first surface 150a of the lens to be inspected can be changed from the central axis of the first face of the lens to be inspected. Consistent.

Further, Fig. 29 shows the shape of the annular focused light 180a and the annular intensity distribution 180b which are respectively irradiated to the subject lens 150 from the reflected light sensor portion 130b or 141a. As shown in Fig. 29, the surface perpendicular to the optical axis of the focused light 180a is a light having an annular intensity distribution 180b. It is shown that the parallel light ray 181a which is the ring-shaped intensity distribution 181b is reflected on the first surface 150a of the lens to be inspected.

The initial setting method of the lens surface deviation amount measuring device 130 according to the fourth embodiment of the present invention, in particular, the adjustment of the optical axis angle of the transmitted light sensor unit 130c will be described. First, the optical axis of the transmitted light sensor unit 130c is based on the optical axis of the light emitted from the reflected light sensor unit 130b. Therefore, the light from the reflected light sensor portion 130b is converted into parallel rays by the lens 138a, and the parallel rays are incident on the transmitted light sensor portion optical system 137. Then, the lens 137a in the transmitted light sensor unit optical system 137 collects light in the transmitted light sensor unit light receiving device 137b, and the angle of the parallel light is measured. Finally, the optical axis angle of the transmitted light sensor unit 130c is adjusted to 0 degree by moving the transmitted light sensor portion holding mechanism platform portion 139 of the transmitted light sensor portion 130c based on the angle of the parallel light. Further, as the transmitted light sensor portion holding mechanism platform portion 139, a rotating platform can be used.

Next, the surface deviation of the lens to be inspected is calculated based on the measured value of the refractive index θ ₁ of the transmitted light of the detected lens 150 as shown in FIG. 30 by the lens surface deviation amount measuring device 130 of the present invention. The method of the amount Δ ₂ is briefly explained. Fig. 30 shows that the parallel ray Li parallel to the central axis of the lens is incident on the lens to be inspected 150. On the second surface 150b of the lens to be inspected, the amount of surface deviation Δ ₂ generated in the lens to be inspected 150 causes the parallel light ray to be refracted. Look like that.

First, in order to measure the angle θ _{1 to} be refracted as shown in Fig. 30, the transmitted light sensor unit optical system 137 is used. The transmitted light sensor unit optical system 137 is composed of a lens (focus distance f11) 137a and a transmitted light sensor unit light receiving device 137b. Then, as shown in Fig. 24, the light transmitted through the inspection lens 150 becomes a parallel ray due to the action of the lens (focus distance f10) 138a, and passes through the half mirror 138c. Next, since the lens (focus distance f11) 137a following the lens 138a functions, the light is concentrated on the transmitted light sensor portion light receiving device 137b. Therefore, the position of the light collecting point can be detected by the light receiving means 137b. Further, in the transmitted light sensor unit optical system 137, as shown in Fig. 24, the position of the point D and the position of the light collecting point have an imaging relationship. As described above, the data processing unit can measure θ ₁ based on the XY position data of the condensed spot position.

Specifically, the distance B from the lowest point of the second surface of the lens to the condensed spot is calculated in advance using a calculation formula as described later (hereinafter also referred to as "back focus B" or simply "B"). Then, the XY position of the condensed point of the parallel ray is measured at the focus position of the lens to be inspected 150, and then the origin is set on the lens central axis LZ based on the XY position, and the deviation amount Δ _{1 is} calculated. Next, based on the deviation amount Δ ₁ and the back focal length B, the refracted angle θ ₁ based on the lens central axis LZ of the laser incident parallel ray passing through the second surface 150b of the inspection lens 150 is calculated. Finally, a line connecting the intersection of the laser incident parallel ray Li and the second surface 150b and the center of the second surface (curvature center) CN2 is L, and the Snell's law is used to calculate the lens center axis LZ. The angle θ _{2 of the} straight line L.

Specifically, the distance B from the lowest point of the second surface of the lens to the condensed spot is calculated in advance using a calculation formula as described later (hereinafter also referred to as "back focus B" or simply "B"). Then, the XY position of the condensed point of the parallel ray is measured at the focus position of the lens to be inspected 150, and then the origin is set on the lens central axis LZ based on the XY position, and the deviation amount Δ _{1 is} calculated. Next, based on the deviation amount Δ ₁ and the back focal length B, the refracted angle θ ₁ based on the lens central axis LZ of the laser incident parallel ray passing through the second surface 150b of the inspection lens 150 is calculated. Finally, a line connecting the intersection of the laser incident parallel ray Li and the second surface 150b and the center of the second surface (curvature center) CN2 is L, and the Snell's law is used to calculate the lens center axis LZ. The angle θ _{2 of the} straight line L.

Next, a specific calculation method of the surface deviation amount Δ ₂ of the inspection lens 150 will be described. In the lens surface deviation amount measuring device 130 according to the fourth embodiment of the present invention, the parameters required for calculating the surface deviation amount Δ ₂ are the following parameters.

n: refractive index of the material of the lens to be inspected

r ₁ : radius of curvature of the first surface of the lens to be inspected

r ₂ : radius of curvature of the second side of the lens to be inspected

t: thickness of the lens to be inspected

Further, for example, the above parameters are set in advance in the data processing unit 130d. Further, the lens surface deviation amount measuring device 130 of the present invention measures the surface deviation amount Δ ₂ using the transmitted light near the center of the detected lens 131a. Therefore, since the transmitted light passes through the paraxial axis of the lens to be inspected, the following calculation is performed based on the paraxial approximation.

First, based on the thickness t of the lens to be inspected 150, the refractive index n, the first surface curvature radius r ₁ and the second surface curvature radius r ₂ , and using Equation 26, the back focus B of the subject lens 150 can be calculated.

Next, the angle of the refracting with respect to the lens central axis LZ of the laser incident parallel ray passing through the second surface of the subject lens 150 is θ ₁ . Based on the geometric configuration and using the deviation amount Δ ₁ and the back focus B, the angle θ ₁ can be expressed by the equation 27.

Then, a line connecting the intersection point LN2 at which the laser light enters the parallel ray with the second surface and the center of curvature CN2 of the second surface is set to L. Next, using the Snell's law as shown in Expression 4, the angle θ ₂ of the straight line L based on the lens central axis LZ can be calculated. As a result, by deforming the equation 28, the angle θ ₂ of the straight line L based on the lens central axis LZ can be expressed by the equation 29.

[Expression 28] nθ ₂ = θ ₂ + θ ₁

Then, when θ ₁ is eliminated by the above formula 29, the equation 27 can be changed to the equation 30.

Here, based on the geometric configuration, the surface deviation amount Δ ₂ can be expressed by the equation 31.

[Expression 31] Δ ₂ = r ₂ θ ₂

Substituting the formula 30 into the formula 31, the formula 32 can be obtained.

Finally, using the parameter and the equation 26 for representing the back focal length B, the back focal length B is eliminated from the equation 32, and the equation 33 is obtained, based on the condensed point deviation amount Δ ₁ as the design parameter, and the first lens to be inspected. The surface curvature r ₁ , the curvature r _{2 of the} second surface of the lens to be inspected, the lens thickness t of the lens to be inspected, and the refractive index n of the lens to be inspected can calculate the surface deviation between the first surface and the second surface of the lens to be inspected. The amount △ ₂ .

Further, using Equation 33 to calculate the amount of deviation △ surface ₂ of the case, regardless of the subject lens is a convex lens or a concave lens, can be determined using Equation 33 come forward shift amount △ _2.

Further, in the lens deviation amount measuring device 130 of the present invention, the surface deviation amount Δ ₂ can be calculated even by the annular focused light. In this case, the condensed spot of the annular focused light is diffused from the focal point FF (hereinafter also referred to as "front focus position") located on the first surface side (reflected light sensor side) of the lens to be inspected. Then, a method of calculating the surface deviation amount Δ ₂ based on the angle θ ₁ ' of the transmitted light transmitted through the detected lens 150 based on the lens central axis LZ will be described. 31 shows that the focused light whose optical axis coincides with the lens central axis LZ of the subject lens 150 is incident on the subject lens 150, and then, as the parallel ray LB inclined with respect to the lens central axis LZ, is emitted from the subject lens 150. Look like. By substituting the above formula 28 into the equation 31, the surface deviation amount Δ ₂ can be expressed by the equation 34. Further, in Fig. 31, θ ₁ ' and θ ₂ ' are substituted for θ ₁ and θ ₂ .

With Equation 34, the amount of surface deviation Δ ₂ can be calculated based on θ ₁ ' . θ ₁ ' is an angle between the parallel ray LB emitted from the second surface 150b of the lens to be inspected and the lens central axis LZ. Therefore, θ ₁ ' can be measured by the transmitted light sensor unit 130c. In the transmitted light sensor portion automatic collimator 138, since the lens central axis LZ is 0 degrees as a reference, the transmitted light sensor portion automatic collimator 138 can obtain θ ₁ ' as a measured value. The transmitted light sensor unit automatic collimator 138 is composed of a lens (focus distance f10) 138a, a transmitted light sensor unit automatic collimator light receiving device 138b, and a half mirror 138c. According to this configuration, because of the action of the lens (focus distance f10) 138a, the parallel light LB that has passed through the lens 150 to be inspected is condensed by the half mirror 138c to the transmitted light sensor unit autocollimator light receiving device 138b. . Therefore, the position of the light collecting point can be detected by the automatic collimator light receiving device 138b of the transmitted light sensor portion. Finally, based on the XY position data of the spot position, the data processing unit can measure θ ₁ ' . Further, in the case where the surface deviation amount Δ ₂ is calculated by Equation 10, the detected lens is limited to a convex lens.

As described above, the lens surface deviation amount measuring apparatus according to the fourth embodiment of the present invention simultaneously irradiates the focused light having a ring-shaped light intensity distribution from the optical axis of the reflected light sensor portion and is irradiated. The parallel rays near the center of the lens to be inspected adjust the position of the lens to be aligned so that the lens central axis of the lens to be inspected (the normal of the first surface of the lens to be inspected) and the optical axis of the reflected light sensor portion become identical. By measuring the position of the light collecting point of the light transmitted through the lens to be inspected, the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

As described above, in the method of calculating the surface deviation amount Δ ₂ by the angle θ ₁ ' of the transmitted light transmitted through the lens to be inspected, the diffused light is irradiated from the front focus position of the detected lens, and The angle between the direction of the transmitted light transmitted through the lens to be inspected and the central axis of the lens is measured, and the amount of surface deviation of the lens to be inspected can be measured without rotating the lens to be inspected.

According to the lens deviation amount measuring device of the present invention, since the lens rotating mechanism to be inspected is not required, the lens surface deviation amount measuring device of the present invention has a simpler structure and can also be used as compared with the prior art device. Shorten the measurement time.

Further, although the embodiments of the present invention have been described, the above-described embodiments are merely described as examples, and the above embodiments do not limit the scope of the present invention. Embodiments of the present invention are not limited to the above embodiments, and Various omissions, substitutions and changes may be made without departing from the scope of the invention. The invention and the scope of the invention are intended to be included within the scope of the invention and the scope of the invention.

[The possibility of industrial use]

The present invention can be applied to measuring the characteristic value of the lens to be inspected by simultaneously irradiating the focused light whose light intensity distribution is annular from the optical axis of the reflected light sensor portion and the parallel light that is irradiated near the center of the detected lens. The present invention is particularly suitable for measuring the thickness of a thin type of test lens having a thickness of 200 μm or less. The present invention can also be applied to adjusting the position of the lens to be inspected so that the lens central axis of the lens to be inspected (the normal of the first surface of the lens to be inspected) and the optical axis of the reflected light sensor portion become identical, and the measurement is transmitted through the measurement. The ring-shaped focused light of the lens or the spot position of the parallel light rays that are irradiated near the center of the lens to be inspected can measure the amount of surface deviation of the lens to be inspected without rotating the lens to be inspected.

29‧‧‧Circular focused light illumination optical system

31‧‧‧Light source (eg laser diode)

32‧‧‧ collimator lens

34‧‧‧Optical components

34a‧‧‧Circular transmission hole

34b‧‧‧ small diameter lens

49a‧‧‧Circular light

49b‧‧‧Parallel rays

50a‧‧‧ focused light

50b‧‧‧ parallel light

Claims (12)

An optical element characteristic measuring apparatus comprising: a focused light for ringing a light intensity distribution on a plane perpendicular to an optical axis; and a parallel light having a center of a light intensity distribution on the optical axis is irradiated to the optical element to be inspected In the above-described annular focused light-illuminating portion, the surface of the optical element to be inspected on the side of the light-emitting portion of the annular focusing light is referred to as a surface, and the opposite side of the surface is referred to as a back surface; The shape of the optical element to be inspected is measured by analyzing the intensity of the light reflected by the surface of the optical element or the back surface of the optical element, analyzing the intensity of the light transmitted through the optical element to be inspected, or analyzing the optical path of the light. The optical element characteristic measuring apparatus according to claim 1, wherein the annular focused light irradiating light portion has a light source, a first optical element, and a first lens; and the light source and the first optical are along the optical axis The light source, the first optical element, and the first lens are disposed in the order of the element and the first lens; a ring-shaped void perpendicular to the optical axis is formed in the first optical element; and has a ring shape The first lens having a diameter of a small diameter inside the gap is disposed in the first optical element so that the optical axis of the optical axis and the optical axis of the first lens become substantially identical. The optical component characteristic measuring device described in claim 1 or 2 Further, the reflected light detecting unit and the processing unit are provided, and the reflected light detecting unit irradiates the annular focused light onto the optical element to be inspected to form a first annular image formed on the surface of the optical element to be inspected. And a second annular image generated on the back surface of the optical element to be inspected is imaged on the light receiving surface, and data for calculating the light intensity of the first annular image and the second annular image is generated; the foregoing processing The portion calculates the thickness of the optical element to be inspected based on a change in the light intensity with respect to a distance in which the optical element to be inspected moves in the optical axis direction. The optical element characteristic measuring apparatus according to claim 3, wherein the optical element to be inspected is a lens, and the processing unit detects light of the first annular image and the second annular image based on the data. The two maximum values of the change in the intensity, and the measured value d which is the difference in the moving distance of the optical element to be inspected corresponding to the two maximum values, the refractive index n of the material of the optical element to be inspected, and the aforementioned Calculating the lens of the optical element to be inspected by calculating a radius of curvature r of the optical element, a center point of the radius of curvature r, and a condensing angle θ _{1 of the} focused light as an angle formed by the optical axis and the focused light Thickness t. The optical element characteristic measuring apparatus according to the fourth aspect of the invention, wherein the point C on which the ring-shaped focused light of the surface of the optical element to be inspected is refracted and the back surface of the optical element to be inspected are annular The slope a and the intercept b of the line segment BC of the condensed point B are respectively set to And b = r - d , use Calculating the distance e between the point C and the optical axis of the ring-shaped focused light. When the radius of curvature r is positive (the optical element to be inspected is a convex lens), the sign of the distance e is positive. In the case where the radius of curvature r is negative (the optical element to be inspected is a concave lens), the sign of the distance e is a negative value, and is used. The thickness t of the lens of the aforementioned optical element to be inspected is calculated. The optical element characteristic measuring apparatus according to the first or second aspect of the invention, wherein the optical element characteristic measuring apparatus includes a reflected light sensor unit, a transmitted light sensor unit, and a data processing unit, wherein the reflected light sensor unit has a The annular focused light is irradiated onto the annular focused light irradiation portion on the optical element to be inspected, and a reflection angle for calculating an optical axis of the annular parallel ray reflected on the surface of the optical element to be inspected is generated. First condensed position data; the transmitted light sensor unit generates second condensed position data for calculating a condensed spot position of the ray of the light irradiated from the annular focused light and transmitted through the optical element to be inspected; The data processing unit calculates the reflection angle based on the first condensed position data, and calculates a condensed spot position of the light transmitted through the optical element to be inspected based on the second condensed position data; the data processing unit is based on the a condensing position data adjusts a position of the aforementioned optical element to be inspected so that the lens of the optical element to be inspected is The mandrel and the annular portion of the focusing optical axis of irradiation light becomes uniform, and based on the position of the focal point, without rotating the optical element to be inspected on the calculated deviation amount of the subject surface of the optical element △ _2. The optical element characteristic measuring apparatus according to claim 6, wherein the optical element to be inspected is a lens, and the processing unit uses the condensed spot position based on a transmitted parallel ray passing through a vicinity of a center of the optical element to be inspected. The calculated deviation amount Δ ₁ , the refractive index n of the material of the optical element to be inspected, the radius of curvature r _{1 of the} surface of the optical element to be inspected, the radius of curvature r _{2 of the} back surface of the optical element to be inspected, and the aforementioned The thickness deviation t of the optical element is calculated to calculate the aforementioned surface deviation amount Δ ₂ . The optical element characteristic measuring apparatus according to claim 7, wherein the use The aforementioned surface deviation amount Δ ₂ is calculated. The optical element characteristic measuring apparatus according to claim 6, wherein the optical element to be inspected is a lens, and the processing unit uses a focus concentrating based on a side of the reflected light sensor unit on the optical element to be inspected. The refraction angle θ ₁ ' of the transmitted parallel ray calculated by the position of the condensed point of the transmitted light sensor portion of the transmitted parallel light ray obtained by the focused optical light transmitted through the optical element to be inspected, and the refraction of the material of the optical element to be inspected The surface deviation amount Δ ₂ is calculated by the rate n and the radius of curvature r _{2 of the} back surface of the optical element to be inspected. The optical element characteristic measuring apparatus according to claim 9, wherein the use The aforementioned surface deviation amount Δ ₂ is calculated. The optical element characteristic measuring apparatus according to any one of claims 1 to 10, wherein the ring-shaped light obtained by arranging three or more light beams at substantially equal intervals on the circumference is used instead of the ring shape. Focused light. The optical element characteristic measuring apparatus according to claim 11, wherein three or more holes through which the three or more light beams pass are formed in the first optical element.