JP2005221365A - Lens performance inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens performance inspection device capable of inspecting a performance of a lens to be inspected at a target image height in a short time, without being affected by noises caused by a displacement quantity detecting marker. <P>SOLUTION: The lens performance inspection device 1 is equipped with: a light irradiation section 13 which irradiates an inspection chart 12 with light; a light blocking member 16 which is disposed between the lens to be inspected 11 and the light irradiation section 13, transmits projection light from an inspection pattern P, and blocks projection light from the displacement quantity detecting marker M; and a moving mechanism 17 which moves the light blocking member 16 from a light blocking position where the projection light from the displacement quantity detecting marker M is blocked, to its retraction position relative to the blocking position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lens performance inspection apparatus for inspecting the optical performance of a lens to be examined.

Conventionally, a pattern image provided on an inspection chart is formed on an image sensor via a test lens such as a photographic lens, and the optical performance of the test lens is inspected by the light intensity distribution of the obtained pattern image. In many cases, the pattern image does not form on the image sensor due to manufacturing variations of the test lens.
In such a case, particularly in an automatic inspection machine, a pattern image is searched by shifting the relative position of the inspection chart and the image sensor, which increases the inspection time.

  In order to solve this problem, an inspection chart of a lens performance inspection apparatus provided with a positional deviation amount detection marker has been proposed (see, for example, Patent Document 1). In the inspection chart described in Patent Document 1, as shown in FIG. 7, the graphical feature amount changes in accordance with the change in the displacement amount and the displacement direction from the inspection pattern (that is, for example, from the inspection pattern P). Label the image data of each misregistration amount detection marker M in the form of a dot (black circle) whose position changes from the center coordinate of each marker range Me as the distance from each other in the X +, X−, Y +, Y− direction increases. I do. Next, the position shift amount detection marker M labeled closest to the center of the image data is selected, and the shift amount and shift direction of the graphic feature amount with respect to the center coordinates of the marker range Me are calculated. .

Since the deviation amount of the feature amount corresponds to the displacement amount from the inspection pattern P and the displacement direction corresponds to the displacement direction from the inspection pattern P, the inspection chart, the imaging unit, By performing the relative positioning, the inspection time of the inspection pattern P can be shortened. This makes it possible to perform a test lens performance inspection at a target image height in a short time. In other words, it is possible to provide an inspection chart for a lens performance inspection apparatus that can perform a performance inspection of a test lens at a target image height in a short time without being affected by variations in the test lens.
JP 2002-39913 A

However, as shown in FIG. 7, the inspection chart of the lens performance inspection apparatus described in Patent Document 1 includes a misregistration amount detection marker. Therefore, light from the misregistration amount inspection marker is flare or the like. The problem of noise becomes.
The present invention has been made in view of the above-described circumstances, and performs performance inspection of a test lens in a short time at a target image height without being affected by noise generated by a misregistration amount detection marker. It is an object of the present invention to provide a lens performance inspection device that can be used.

In order to achieve the above object, the present invention provides the following means.
The lens performance inspection apparatus according to the present invention includes an inspection pattern for inspecting the performance of a lens to be tested, and a positional deviation amount detection in which a graphic feature amount changes in accordance with a positional deviation amount and a positional deviation direction from the inspection pattern. An inspection chart in which markers for inspection are arranged around the inspection pattern, an optical system for lens performance inspection including the lens to be inspected, and an image of the inspection pattern imaged by the lens to be inspected through the optical system In the lens performance inspection apparatus, comprising: an image pickup unit that picks up images; and an arithmetic processing unit that performs calculation processing based on a light intensity distribution signal corresponding to an image of the inspection pattern that is an output signal from the image pickup unit. A light irradiating unit for irradiating the chart with light, and disposed between the light irradiating unit and the lens to be inspected, allowing projection light from the inspection pattern to pass therethrough, and projecting from the positional deviation amount detection marker A light shielding member for shielding the light shielding member is characterized by comprising a moving mechanism for moving to a position to retract from the position location and shielding for shielding the projection light from the positional deviation amount detection mark.

  In this invention, the image of the inspection chart irradiated from the light irradiation unit is formed on the imaging means by the lens to be detected, and the position shift is detected by the position shift amount detection marker of the inspection chart. Then, based on the positional deviation amount, the imaging unit is moved so that the positional deviation between the inspection chart and the imaging unit is eliminated. Thereafter, the light shielding member is inserted into the position where the projection light from the positional deviation amount detection marker is shielded by the moving mechanism, and only the projection light from the inspection pattern is imaged on the test lens. That is, by providing the light shielding member, it is possible to remove noise such as flare due to the positional deviation amount detection marker.

  The lens performance inspection apparatus according to the present invention forms an image by the test lens via the test pattern for the performance test of the test lens, the optical system for the lens performance test including the test lens, and the optical system. Lens performance inspection comprising: an imaging unit that captures an image of the inspection pattern; and an arithmetic processing unit that performs arithmetic processing based on a light intensity distribution signal corresponding to the image of the inspection pattern that is an output signal from the imaging unit In the apparatus, a projection unit that projects a misregistration amount detection marker whose graphic feature amount changes to the periphery of the inspection pattern, and a control mechanism that controls projection of the misregistration amount inspection mark from the projection unit. It is characterized by providing.

  In the present invention, the control mechanism displays a misregistration amount detection marker from the projection unit around the inspection pattern. Then, the imaging unit is moved so that the positional deviation between the inspection chart and the imaging unit is eliminated. Thereafter, the projection from the projection unit is stopped by the control means, and the projection light from the inspection pattern is imaged on the test lens. That is, the control mechanism can control the presence or absence of projection of the positional deviation amount detection marker from the projection unit as necessary, so that the positional deviation amount detection marker is not projected when it is not necessary. Can do. Therefore, it is possible to remove noise such as flare caused by the position shift amount detection marker with a simple operation. In addition, it is possible to shorten the inspection time by projecting a positional deviation amount detection marker corresponding to the lens to be examined.

  The lens performance inspection apparatus according to the present invention forms an image by the test lens via the test pattern for the performance test of the test lens, the optical system for the lens performance test including the test lens, and the optical system. Lens performance inspection comprising: an imaging unit that captures an image of the inspection pattern; and an arithmetic processing unit that performs arithmetic processing based on a light intensity distribution signal corresponding to the image of the inspection pattern that is an output signal from the imaging unit In the apparatus, an inspection chart in which a misregistration amount detection marker whose graphic feature amount changes is applied to the periphery of the inspection pattern with a fluorescent material, illumination means for illuminating the fluorescent material, and on / off of the illumination means And a control mechanism for controlling OFF.

  In this invention, the illumination unit is illuminated by the control mechanism, and the fluorescent material applied around the inspection pattern is caused to emit light. Then, the imaging unit is moved so that the positional deviation between the inspection chart and the imaging unit is eliminated. Thereafter, the illumination from the illuminating means is stopped by the control means, and the light transmitted through the inspection pattern is imaged on the test lens. In other words, since the display of the misregistration amount detection marker can be controlled by the illumination means, it is possible to remove noise such as flare caused by the misregistration amount detection marker with a simple operation.

The present invention has the following effects.
According to the lens performance inspection apparatus of the present invention, at the time of inspection pattern search, an inspection pattern at a target image height can be found in a short time from a misregistration amount detection marker arranged around the inspection pattern. Further, at the time of lens performance inspection, it is possible to perform performance inspection of the lens to be tested without being affected by noise due to the positional deviation amount detection marker.

Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the lens performance inspection apparatus 1 according to the present embodiment includes a measurement unit 10 having an optical system for lens performance inspection, and a control processing unit that performs arithmetic processing based on an output signal of the measurement unit 10. 20.

The measuring unit 10 includes a lens 11 to be inspected, an inspection chart 12 having the pattern shown in FIG. 7, and a light source (light) that is arranged on the back surface 12 a side of the inspection chart 12 and illuminates the inspection chart 12. (Irradiation unit) 13, a two-dimensional imaging device (imaging means) 14 that images the inspection chart 12, an imaging device moving mechanism 15 that moves the two-dimensional imaging device 14, and between the light source 13 and the test lens 11. And a light shielding member 16 disposed on the surface.
In the figure, A is an optical axis, which indicates the central axis of light when light emitted from the light source 13 passes through the inspection chart 12.

  As shown in FIG. 7, the inspection chart 12 includes a positional deviation amount detection marker M in which a graphic feature amount changes with a change in the positional deviation amount and the positional deviation direction from the inspection pattern P. It is arranged around. The inspection chart 12 is disposed to face the two-dimensional image sensor 14 with the lens 11 to be examined interposed therebetween.

As shown in FIG. 2, the light shielding member 16 has an opening 16 a having the same size as the inspection pattern P, and is arranged so that the inspection pattern P is placed on the optical axis A. Thereby, the projection light from the inspection pattern P is transmitted, and the projection light from the misregistration amount detection marker M is shielded. In addition, the light shielding member 16 includes a moving mechanism 17 that moves the projection light from the misregistration amount detection marker M to a position where the projection light is shielded and a position where the projection light is retracted from the light shielding position.
The image sensor moving mechanism 15 is a mechanism for moving the two-dimensional image sensor 14 (such as movement in the X and Y directions and rotational movement shown in FIG. 1).

  As shown in FIG. 3, the control processing unit 20 includes a control unit 21 that performs overall control, an image height value to be inspected in advance, and a standard value (MTF ( (Modulation Transfer Function) value) and calculation of the position where the MTF value calculation or measurement position has a predetermined image height and the positional deviation between the inspection chart 12 and the two-dimensional image sensor 14 is eliminated. An arithmetic processing unit (arithmetic processing unit) 23 that performs various arithmetic operations, a display unit 24 that displays various data, an image processing unit 25 that performs image processing such as labeling (feature amount extraction by particle analysis), and a control unit 21 And a drive unit 26 that drives the image sensor moving mechanism 15 based on the control of the image sensor.

  Further, the moving mechanism 17 is controlled by the control processing means 20 and is movable. Further, cables L1 and L2 are connected to the two-dimensional image sensor 14 and the moving mechanism 17, and an output signal from the two-dimensional image sensor 14 is taken in and drive control of the moving mechanism 17 is performed. .

Next, the operation of the lens performance inspection apparatus of the present embodiment having the above configuration will be described below.
In order to inspect the performance of the lens 11 to be inspected using the lens performance inspection apparatus 1 according to the present embodiment, first, the control processing unit 20 operates the moving mechanism 17 to start from the position deviation amount detection marker M. The light shielding member 16 is retracted to a position where the projection light is not shielded. When the light source 13 is activated and light is incident on the inspection chart 12, an image of the inspection chart 12 is formed on the two-dimensional image sensor 14 by the lens 11 to be examined. This image is converted into an electric signal corresponding to the light intensity distribution by the two-dimensional image sensor 14, and is taken into the control processing means 20 as two-dimensional image data via the cable L1. The two-dimensional image data has a one-to-one correspondence with the pixel arrangement of the two-dimensional image sensor 14, and is data obtained by digitizing a light intensity distribution that has a larger value at a portion having a higher light intensity.

Here, when the lens 11 to be examined is manufactured almost as designed, the pattern data of the inspection pattern P is located at the approximate center of the captured image data. For this reason, the MTF value of the test lens 1 can be calculated by performing an FFT (Fast Fourier Transform) operation on the range corresponding to the inspection pattern P in the calculation unit 23.
On the other hand, when the test lens 11 has a manufacturing variation with respect to the design value, it is taken into the control processing means 20 in a state where the two-dimensional image data positional deviation amount detection marker M is included.

  When there is such a variation, the current positional relationship between the inspection chart 12 and the two-dimensional image sensor 14 is obtained from the graphical feature amount of the positional deviation amount detection marker M. Thereafter, the calculation unit 23 calculates a position where the measurement position becomes a predetermined image height and the positional deviation amount between the inspection chart 12 and the two-dimensional imaging element 14 is eliminated. The control unit 21 outputs an operation command to the image sensor moving mechanism 15 via the drive unit 26 based on the calculation result of the calculation unit 23, the measurement position becomes a predetermined image height, and the inspection charts 12 and 2 The image sensor moving mechanism 15 is driven to adjust the position of the two-dimensional image sensor 14 so that the position shift amount with respect to the two-dimensional image sensor 14 is eliminated.

  Next, after the operation of the image sensor moving mechanism 15 is completed, the control processing means 20 operates the moving mechanism 17 so that the projection light from the positional deviation amount marker M does not appear on the two-dimensional image sensor 14. Move to position. That is, only the projection light from the inspection pattern P is imaged on the two-dimensional image sensor 14 by the lens 11 to be examined. After that, the control processing means 20 takes in the image data from the two-dimensional image sensor 14 again, and the fetched image data corrects the amount of positional deviation between the inspection chart 12 and the two-dimensional image sensor 14, and further, a predetermined image. The image data is high. Therefore, the MTF value of the test lens 1 at a predetermined image height can be calculated by performing an FFT (Fast Fourier Transform) operation on the range corresponding to the inspection pattern P in the calculation unit 23. Next, the control unit 21 compares and determines the calculated MTF value and the MTF value of the standard value of the pass / fail determination stored in the storage unit 22 in advance, and displays the pass / fail result on the display unit 24 to inform the operator. Present.

  According to the lens performance inspection apparatus 1 in the present embodiment described above, when the MTF value of the lens 11 to be tested is obtained, the projection light from the misregistration detection marker M is shielded by the light shielding member 16, and therefore the inspection is performed. Only the projection light from the pattern P can be incident on the test lens 11. Therefore, the position of the two-dimensional image sensor 14 can be corrected in a short time, and the inspection can be performed by removing noise caused by the positional deviation amount detection marker M.

Next, a second embodiment according to the present invention will be described with reference to FIGS. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the lens performance inspection apparatus 30 according to the present embodiment, the difference from the first embodiment is that the projection for projecting the displacement amount detection marker M instead of the light shielding member 16 and the moving mechanism 17 as shown in FIG. The point provided with the portion 32 and the point that only the inspection pattern P is provided as the inspection chart 31 as shown in FIG.

  The projection unit 32 projects a misregistration amount detection marker M whose graphic feature value changes on the periphery of the inspection pattern P. Further, the projection unit 32 is provided in the vicinity of the two-dimensional imaging device 14, and is arranged at a position where the displacement amount detection marker M can be projected onto the surface of the inspection chart 12. The projection unit 32 is connected to a control processing unit (control mechanism) 20 via a cable L3, and the control processing unit 20 controls the driving of the projection unit 32. The control processing means 20 takes in the output signal of the two-dimensional image sensor 14 via the cables L1 and L3, and controls the driving of the projection unit 32 based on the output signal.

Next, the operation of the lens performance inspection apparatus of the present embodiment having the above configuration will be described below.
In order to inspect the performance of the lens 11 to be inspected using the lens performance inspection apparatus 30 according to the present embodiment, first, the control processing means 20 moves the positional deviation amount detection marker M from the projection unit 32 to the inspection chart 31. Project onto the surface. Here, when the test lens 11 has a manufacturing variation with respect to the design value, it is taken into the control processing means 20 in a state in which the displacement amount detection amount marker M projected from the projection unit 32 is included. .

  When there is such a variation, the position where the measurement position becomes the predetermined image height and the positional deviation amount between the inspection chart 31 and the two-dimensional imaging element 14 is eliminated by the control unit 21 as in the first embodiment. Then, the image sensor moving mechanism 15 is driven to adjust the position of the two-dimensional image sensor 14.

  Next, after the operation of the image sensor moving mechanism 15 is completed, the control processing unit 20 stops the projection of the positional deviation amount marker M from the projection unit 32. That is, since only the test pattern P is written on the test chart 31, only the projection light from the test pattern P is imaged on the two-dimensional image sensor 14 by the test lens 11. Thereafter, the control processing unit 20 takes in the image data from the two-dimensional imaging device 14 again, performs an FFT (Fast Fourier Transform) calculation in the calculation unit 23 in the same manner as in the first embodiment, and performs the MTF of the lens 11 to be examined. A value can be calculated.

  According to the lens performance inspection device 30 in the present embodiment described above, the control processing unit 20 can control the projection of the misregistration detection marker M from the projection unit 32. Therefore, when obtaining the MTF value of the lens 11 to be examined, the misregistration detection marker M can be prevented from being displayed, so that it is possible to inspect without removing noise due to the misregistration amount detection marker M. Further, it is possible to shorten the inspection time by projecting the positional deviation amount detection marker M corresponding to the lens 11 to be examined.

Next, a third embodiment according to the present invention will be described with reference to FIG.
In the lens performance inspection apparatus 40 of the present embodiment, the difference from the first embodiment is that, instead of the light shielding member 16 and the moving mechanism 17, as shown in FIG. It is a point that has.

As shown in FIG. 7, the inspection chart 41 is obtained by applying a misregistration amount detection marker M whose graphic feature amount changes around the inspection pattern P with a fluorescent material. Here, the fluorescent substance is an inorganic fluorescent material such as europium (red), terbium (green), and cerium (blue).
The illumination means 42 is provided in the vicinity of the two-dimensional imaging device 14 and illuminates the position shift amount detection marker M applied to the surface of the inspection chart 41. In addition, a control processing means (control mechanism) 20 is connected to the illumination means 42 via a cable L4, and the control processing means 20 controls on / off of the illumination means 42. The control processing means 20 takes in the output signal of the two-dimensional imaging device 14 via the cables L1 and L4 and controls the driving of the illumination means 42 based on the output signal.

Next, the operation of the lens performance inspection apparatus of the present embodiment having the above configuration will be described below.
In order to inspect the performance of the lens 11 to be inspected using the lens performance inspection apparatus 40 according to the present embodiment, first, the control unit 20 operates the illuminating unit 42 to detect a displacement amount detection marker applied with a fluorescent material. Illuminate M. Here, when the test lens 11 has a manufacturing variation with respect to the design value, it is taken into the control processing means 20 in a state in which the displacement amount detection amount marker M illuminated by the illumination means 11 is included. .

When there is such a variation, the position where the measurement position becomes a predetermined image height and the positional deviation amount between the inspection chart 41 and the two-dimensional image sensor 14 is eliminated by the control unit 21 as in the first embodiment. The image sensor moving mechanism 15 is driven so that the position of the two-dimensional image sensor 14 is adjusted.
After the operation of the image sensor moving mechanism 15 is completed, the control processing unit 20 stops the illumination on the positional deviation amount marker M from the illumination unit 42. That is, since the marker M provided on the inspection chart 41 is not displayed, only the projection light from the inspection pattern P is imaged on the two-dimensional image sensor 14 by the lens 11 to be examined. Thereafter, the control processing means 20 takes in the image data from the two-dimensional imaging device 14 again, performs an FFT (Fast Fourier Transform) calculation in the calculation unit 23 in the same manner as in the first embodiment, and performs the MTF of the lens 11 to be examined. A value can be calculated.

  According to the lens performance inspection apparatus 40 in the present embodiment described above, the control processing unit 20 can control the irradiation of the misregistration detection marker M from the illumination unit 42. Therefore, when obtaining the MTF value of the lens 11 to be examined, the misregistration detection marker M can be prevented from being displayed, so that it is possible to inspect without removing noise due to the misregistration amount detection marker M.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

It is the schematic which shows the whole lens performance inspection apparatus in 1st Embodiment of this invention. It is an enlarged view of the light-shielding member used for the lens performance inspection apparatus of FIG. It is a block diagram which shows the structure of the control processing means of the lens performance inspection apparatus in this invention. It is the schematic which shows the whole lens performance inspection apparatus in 2nd Embodiment of this invention. It is a top view which shows an example of the chart for a test | inspection used for this invention. It is the schematic which shows the whole lens performance inspection apparatus in 3rd Embodiment of this invention. It is a top view which shows the chart for a test | inspection provided with the marker for position shift amount detection.

Explanation of symbols

P Inspection pattern M Position shift amount detection marker 1, 30, 40 Lens performance inspection device 11 Test lens 12, 31, 41 Inspection chart 13 Light source (light irradiation unit)
14 Two-dimensional imaging device (imaging means)
16 light shielding member 17 moving mechanism 20 control processing means (control mechanism)
23 Calculation unit (calculation processing unit)
32 Projection part 42 Illumination means

Claims (3)

An inspection pattern for performance inspection of the lens to be tested;
An inspection chart in which a misregistration amount detection marker in which a graphic feature amount changes with a change in misregistration amount and misalignment direction from the inspection pattern, is arranged around the inspection pattern,
An optical system for inspecting lens performance including the test lens;
An image pickup means for picking up an image of the inspection pattern imaged by the test lens via the optical system;
In a lens performance inspection apparatus including an arithmetic processing unit that performs arithmetic processing based on a light intensity distribution signal corresponding to an image of the inspection pattern that is an output signal from the imaging unit,
A light irradiator for irradiating the inspection chart with light;
A light shielding member that is disposed between the light irradiation unit and the lens to be examined, transmits the projection light from the inspection pattern, and shields the projection light from the misregistration amount detection marker;
An apparatus for inspecting lens performance, comprising: a moving mechanism for moving the light shielding member to a position where the projection light from the positional deviation amount detection marker is shielded and a position where the light is retracted from the light shielding position. An inspection pattern for performance inspection of the lens to be tested;
An optical system for inspecting lens performance including the test lens;
An image pickup means for picking up an image of the inspection pattern imaged by the test lens via the optical system;
In a lens performance inspection apparatus including an arithmetic processing unit that performs arithmetic processing based on a light intensity distribution signal corresponding to an image of the inspection pattern that is an output signal from the imaging unit,
A projection unit that projects a misregistration amount detection marker whose graphic feature amount changes to the periphery of the inspection pattern;
A lens performance inspection apparatus comprising: a control mechanism that controls projection of the misregistration amount inspection mark from the projection unit. An inspection pattern for performance inspection of the lens to be tested;
An optical system for inspecting lens performance including the test lens;
An image pickup means for picking up an image of the inspection pattern imaged by the test lens via the optical system;
In a lens performance inspection apparatus including an arithmetic processing unit that performs arithmetic processing based on a light intensity distribution signal corresponding to an image of the inspection pattern that is an output signal from the imaging unit,
An inspection chart in which a marker for detecting a displacement amount in which a graphical feature amount changes is applied around the inspection pattern with a fluorescent material, and
Illumination means for illuminating the fluorescent material;
And a control mechanism for controlling on / off of the illumination means.

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