JP2007315959A - Lens-measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens-measuring device capable of smoothly measuring lenses of different kinds. <P>SOLUTION: In this lens-measuring device for measuring the optical characteristics of a lens 1, when a tray 7 for storing the lens 1 is arranged on a lens measuring position, the kind of the lens 1 stored in the tray 7 is detected based on information attached to the tray 7, and measurement setting of a measuring part 2 is performed, corresponding to the kind of the lens 1. As a result, there is no need for the operator of a device to perform measurement setting, corresponding to the kind of the lens 1 that is to be measured, to thereby enable smooth measuring work. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens measuring device that measures optical characteristics of a lens.

2. Description of the Related Art Conventionally, as a lens measuring device that measures the optical characteristics of a lens, for example, a measuring device that measures the MTF value of a lens or the MTF-defocus characteristic is known, as described in Japanese Patent Application Laid-Open No. 2004-294076. ing. In this apparatus, light such as a halogen lamp is incident on a test lens disposed in the apparatus via a reference chart, and a light image emitted from the test lens is detected by a solid-state imaging device. It is intended to measure the MTF value and the MTF-defocus characteristic.
JP 2004-294076 A

  However, in such a lens measuring apparatus, when measuring different types of test lenses, there is a problem that the measuring operation cannot be performed smoothly. For example, if the focal length of the lens changes when measuring different types of test lenses, it is necessary to change the setting of the measurement system, such as the setting position of the reference chart. Every time the change is made, it is complicated work for the worker to change the setting of the measurement system, and the measurement work cannot be performed efficiently. In addition, if the reference chart is not set to an appropriate position by mistake in changing the setting, accurate measurement cannot be performed, and in some cases, the apparatus may be damaged.

  Therefore, the present invention has been made to solve such a technical problem, and by automatically measuring and setting according to the type of lens to be measured, it is possible to smoothly measure different types of lenses. An object of the present invention is to provide a lens measuring device.

  That is, the lens measuring device according to the present invention is a lens measuring device that measures the optical characteristics of a lens, and a holder that holds a lens to be measured, and the holder is disposed at a lens measurement position. Detection means for detecting the type of lens held by the holder based on information attached to the holder, and measurement setting means for performing measurement setting of the measurement unit according to the type of lens detected by the detection means And is configured.

  According to the present invention, the type of the lens is detected based on the information given to the holder when the holder holding the lens is arranged at the lens measurement position, and the measurement setting of the measurement unit is performed according to the lens. Is called. For this reason, it is not necessary for the operator of the lens measurement device to set measurement according to the type of lens to be measured, and the measurement operation can be performed smoothly. Further, since the type of the lens is automatically recognized by arranging the holder at the lens measurement position, it is possible to prevent the measurement from being set by mistake in the type of the lens.

  The lens measuring device according to the present invention is a device that arranges a chart at the focal position of the lens and measures the optical characteristics of the lens by back projection, wherein the measurement setting means determines the chart according to the type of the lens. It is preferable to set the position.

  According to the present invention, by measuring the optical characteristics of the lens by back projection, the chart is arranged at a position close to the lens. In this case, since the measurement setting means automatically sets the chart position according to the lens, it is possible to prevent a situation in which the operator of the apparatus makes a measurement setting accidentally and the chart is damaged due to contact with the holder or the lens. it can.

  In the lens measuring device according to the present invention, it is preferable that at least MTF is measured as an optical characteristic of the lens.

  According to the present invention, by automatically measuring and setting according to the type of lens to be measured, different types of lenses can be measured smoothly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the constituent ratios of members and portions formed in the members in the drawings do not necessarily match those described.

  FIG. 1 is a schematic configuration diagram of a lens measuring apparatus according to an embodiment of the present invention. The lens measurement device according to the present embodiment is a device that measures the optical characteristics of the lens 1 and is used, for example, for measuring MTF (Modulation Transfer Function). The lens measurement device includes a measurement unit 2, an analysis control unit 3, a monitor 4, a determination unit 5, and a power supply unit 6. The measuring unit 2 measures the optical characteristics of the lens 1. The measurement unit 2 and the power supply unit 6 constitute an apparatus main body, and each component is accommodated in, for example, separate casings 21 and 61.

  The measurement unit 2 is placed on the power supply unit 6. For example, the measurement unit 2 is placed on the power supply unit 6 via the vibration isolating rubber 62 and is provided so that vibrations generated by the operation of the power supply unit 6 are not transmitted. Thereby, the optical characteristic of the lens 1 can be measured in an environment with little vibration.

  The lens 1 which is a measurement object is held on the tray 7 and measured. The tray 7 is a holder that holds the lens 1 and has a structure that supports the lens 1 so that light can be transmitted. It is preferable to use a tray 7 that can accommodate a plurality of lenses 1 at a time. The measurement unit 2 is provided with an XY stage 22 on which the tray 7 is placed. The XY stage 22 is configured to place the tray 7 and to move the tray 7 in the left-right direction that is the X direction and the front-rear direction that is the Y direction, and the lens 1 to be measured is moved by the movement of the tray 7. . Any XY stage 22 may be used as long as it can move the tray 7 in the X and Y directions.

  The XY stage 22 is provided with a detection unit 22 a that detects the type of the lens 1 held on the tray 7. The detection unit 22 a detects the type of the lens 1 held by the tray 7 based on information from the identification unit 71 provided on the tray 7. Further, the detection unit 22 a detects the identification number of the tray 7 based on the information of the identification unit 71 provided on the tray 7. The identification number of the tray 7 is a number for individually identifying the same type of tray 7, and a different identification number is assigned to each tray 7. As the identification number of the tray 7, it is preferable to assign a continuous serial number.

  A chart 23 is arranged in the measurement unit 2. The chart 23 forms an input image input to the lens 1, and is arranged between the integrating sphere 24 and the lens 1. The measuring unit 2 measures the optical characteristics of the lens 1 by back projection. That is, the chart 23 for projecting the optical image onto the lens 1 is disposed at the focal position of the lens 1.

  The chart 23 is attached to the Z stage 25. The Z stage 25 is configured to be able to move the chart 23 in the vertical direction, which is the Z direction, and arbitrarily moves the chart 23 toward and away from the lens 1. Thereby, the position of the chart 23 relative to the lens 1 can be adjusted. Any Z stage 25 may be used as long as it can move the chart 23 in the Z direction.

  An integrating sphere 24 is installed in the measurement unit 2. The integrating sphere 24 serves as a light emission source that emits input light toward the chart 23, and is attached to a position below the chart 23, for example. The integrating sphere 24 is a sphere having an output port 24a and having a diffusion surface 24b formed on the inner surface. The light emitted from the light source unit 63 is incident on the integrating sphere 24 through the light guide 64. The light incident on the integrating sphere 24 is repeatedly reflected inside the integrating sphere 24, and is output as light with very little light amount unevenness from the output port 24a.

  A camera 26 is installed in the measurement unit 2. The camera 26 is an imaging unit that receives an output image output from the lens 1. As the camera 26, for example, a camera provided with a solid-state imaging device such as a charge coupled device (CCD) is used. The output image of the lens 1 is an image in which the input image of the chart 23 input to the lens 1 is formed on the camera 26 by the lens 1.

  As the camera 26, it is preferable to use a plurality of cameras in order to detect optical characteristics of different portions of the lens 1. For example, nine cameras 26 are installed. In this case, three are arranged in the left-right direction and the front-back direction. Thereby, the optical characteristics in nine places on the front, rear, left and right of the lens 1 can be measured. An image reception signal of the camera 26 is input to the analysis control unit 3.

  The power source unit 6 is provided with a light source unit 63. The light source unit 63 is a light source that emits light input to the integrating sphere 24. For example, a light source unit including a halogen lamp is used. The light output from the light source unit 63 is input to the integrating sphere 24 through the light guide 64. The power supply unit 6 is provided with a drive unit 64. The drive unit 64 performs drive control of the XY stage 22 and the Z stage 25. For example, when the XY stage 22 and the Z stage 25 are operated by driving a pulse motor, the drive unit 64 is configured by a pulse motor controller. The drive unit 64 outputs drive signals to the XY stage 22 and the Z stage 25 according to the control signal output from the analysis control unit 3.

  The power supply unit 6 is provided with a control unit 65. The control unit 65 mainly performs light emission control of the light source unit 63. The control unit 65 receives a detection signal from the detection unit 22 a of the XY stage 22 and outputs the detection signal to the analysis control unit 3. The power supply unit 6 is provided with a power supply 66. The power source 66 is a power supply source for the light source unit 63, the drive unit 64, and the control unit 65. In addition, a fan 67 is installed in the power supply unit 6. The fan 67 functions as a cooling unit that discharges and cools the heat in the power supply unit 6. For example, a fan provided with rotating blades is used.

  The analysis control unit 3 controls the entire apparatus, and is configured mainly by a computer including a CPU, a ROM, and a RAM, for example. As the analysis control unit 3, for example, a main body of a personal computer is used. The analysis control unit 3 recognizes the type of the lens 1 to be measured based on the information of the tray 7 attached to the measurement unit 2, and sets the measurement of the lens optical characteristic according to the type of the lens 1. Function as. For example, the measurement control data corresponding to the type of the lens 1 is registered in the analysis control unit 3. Specifically, position setting data of the chart 23 corresponding to the type of the lens 1, movement position data of the XY stage 22 corresponding to the type of the tray 7, and the like are registered. The analysis control unit 3 functions as an analysis unit that receives an image reception signal of the camera 26 and analyzes optical characteristics such as MTF of the lens 1 based on the image reception signal.

  The monitor 4 is connected to the analysis control unit 3 and functions as display means for displaying the measurement result of the optical characteristics of the lens 1 and the like. The monitor 4 also displays measurement settings when the lens 1 is measured.

  The determination unit 5 determines the measurement result of the lens 1 held on the tray 7. The determination unit 5 is configured to be able to mount the tray 7 and includes a recognition unit 51 that recognizes the mounted tray 7 and a display unit 52 that displays the lens 1 that has become the measurement result NG. The determination unit 5 is connected to the analysis control unit 3 and can acquire detection information of the tray 7 and measurement result information of the lens 1.

  When the measured tray 7 is placed on the determination unit 5, the recognition unit 51 recognizes the tray 7 based on the identification unit 71 of the tray 7. And the measurement result of each lens 1 hold | maintained at this tray 7 is acquired from the analysis control part 3, and the display part 52 displays the lens 1 of the measurement result NG with a specific color. For example, the display unit 52 is provided with a plurality of light emitters corresponding to the arrangement positions of the respective lenses 1 on the tray 7, and causes the light emitters corresponding to the NG lens 1 to emit red light. As a result, the operator of the apparatus can easily determine the lens 1 having the measurement result NG from the plurality of lenses 1 held, and can remove the NG lens 1 from the tray 7.

  FIG. 2 shows a plan view of the tray 7. 3 is a cross-sectional view of the tray 7 taken along line III-III in FIG. FIG. 4 is a side view of the tray 7 as viewed from IV-IV in FIG.

  As shown in FIGS. 2 and 3, the tray 7 has a holding portion 72 that holds the plurality of lenses 1. The holding part 72 is configured to accommodate the lens 1 by, for example, denting the upper surface of the tray 7 downward. The holding portion 72 is provided with a through hole 73 formed through the bottom portion. The through hole 73 is a hole for transmitting an input image at the time of lens measurement. The holding portions 72 are formed to be arranged vertically and horizontally, for example, 6 × 6 pieces, and 36 pieces are formed on the tray 7.

  As shown in FIG. 4, the tray 7 is provided with an identification unit 71. The identification unit 71 indicates the type and identification number of the tray 7, and for example, a combination of a plurality of concave and convex portions 71a is used. The identification unit 71 is configured by arranging N uneven portions 71a that are uneven on the lower side, and can set the unevenness of the uneven portion 71a to construct N-bit information. By setting the type of tray 7 and the identification number of tray 7 according to the N-bit information, it is possible to recognize the type of tray 7 and the identification number of tray 7 based on the N-bit information. Become. For example, seven irregularities 71a are formed in the identification unit 71 and have 7-bit information.

  As the detection unit 22a that detects the type of the tray 7 and the identification number of the tray 7 based on the identification unit 71 of the tray 7, for example, a detection unit having a switch that is turned on / off according to the unevenness of the uneven portion 71a is used. The detection unit 22a detects the uneven state of the uneven portion 71a in the identification unit 71 of the tray 7 according to the on / off state of the switch, and based on the uneven state, the type of the tray 7, that is, the lens 1 held on the tray 7 is detected. The type and the identification number of the tray 7 are detected. Further, the recognition unit 51 of the determination unit 5 may be configured using the same one as the detection unit 22a.

  The detection unit 22a and the recognition unit 51 may be other than those described above as long as the information on the tray 7 can be read. For example, a barcode is attached to the tray 7, the barcode is read, and the tray 7 is read. This information may be detected.

  FIG. 5 is a plan view of the chart 23.

  As shown in FIG. 5, the chart 23 is configured by a plate body that allows light transmission only in a portion where the slit 23 a is formed and blocks light transmission in other portions. The slit 23a is formed such that, for example, a measurement point p1 at the center position and a plurality of measurement points p2 to p9 arranged radially around the opening are formed in a cross shape. Alternatively, the measurement points p1 to p9 may be arranged in three rows and three rows. At each of the measurement points p1 to p9, it is preferable to form a cross in the slit 23a. By providing the plurality of measurement points p1 to p9 in the slit 23a as described above, the optical characteristics of each part of the lens 1 can be individually measured, and the optical characteristics of the lens 1 can be accurately measured.

  Next, the basic operation of the lens measuring apparatus according to this embodiment will be described.

  FIG. 6 is a flowchart showing the basic operation of the lens measuring apparatus according to this embodiment. The control process in FIG. 6 is mainly executed by the analysis control unit 3. As shown in S <b> 10 of FIG. 6, first, it is determined whether or not the tray 7 is mounted at the measurement position of the measurement unit 2. This determination process may be performed based on, for example, a detection signal from the detection unit 22a of the XY stage 22. When it is determined in S10 that the tray 7 is mounted at the measurement position of the measurement unit 2, a process for reading tray identification information is performed (S12).

  The tray identification information reading process is performed based on the detection signal of the detection unit 22a. That is, the type of the tray 7 and the identification number of the tray 7 are detected based on the 7-bit information included in the detection signal of the detection unit 22a, and the type of the tray 7, the type of the lens 1 held on the tray 7, and The identification number of the tray 7 is read.

  And it transfers to S14 and a measurement setting process is performed. This measurement setting process is a process for setting the measurement system when measuring the optical characteristics of the lens 1. For example, as the measurement setting, the position of the chart 23 is set corresponding to the focal length of the lens 1. A drive control signal is output from the analysis control unit 3 to the drive unit 64 in accordance with the type of the lens 1, the Z stage 25 is activated in response to the drive signal of the drive unit 64, and the position setting in the Z direction of the chart 23 is performed. . With such measurement settings, it is not necessary for the operator of the apparatus to perform measurement settings according to the type of the lens 1, and the measurement operation can be performed smoothly. Moreover, it is possible to prevent erroneous measurement settings.

  Further, as a measurement setting, the movement setting program for the XY stage 22 is read in correspondence with the lens 1 holding position of the tray 7. Further, as a measurement setting, the amount of light output from the integrating sphere 24 may be set according to the type of the lens 1.

  Then, the process proceeds to S16, and it is determined whether or not the measurement start button is turned on. When the operator of the apparatus presses a measurement start button (not shown), it is determined that the measurement start button is turned on. If it is determined that the measurement start button is turned on, a measurement process is performed (S18).

  In the measurement process, the XY stage 22 is operated so that the lens 1 to be measured is directly above the chart 23, the light is output from the integrating sphere 24, and the imaging of the camera 26 that images the optical image output from the lens 1. This is done by analyzing the optical characteristics of the lens 1 based on the image. The light emitted from the integrating sphere 24 passes through the slit 23 a of the chart 23 and enters the lens 1. The optical image of the slit 23 a output from the lens 1 is picked up by the camera 26. At that time, the cameras 26 respectively assigned to the measurement points p1 to p9 of the slit 23a take optical images at the measurement points p1 to p9.

  As an optical characteristic of the lens 1, MTF is measured. The MTF is calculated by, for example, obtaining a line image intensity distribution of the optical image image of the slit 23a and performing a Fourier transform thereof. This MTF is calculated for each of the measurement points p1 to p9. Further, the optical characteristics of the MTF with respect to the spatial frequency as shown in FIG. 7 and the optical characteristics of the MTF with respect to the defocus as shown in FIG. 8 are calculated. Further, as the optical characteristics of the lens 1, a focal length, a focal depth, an eccentric state, and the like of the lens 1 are measured. These optical characteristics are preferably measured at each of the measurement points p1 to p9, similarly to the MTF.

  And it transfers to S20 of FIG. 6 and a measurement result judgment process is performed. This measurement result determination process is a process for determining whether or not the measured optical characteristic of the lens 1 is a characteristic within a preset allowable range. For example, it is determined whether or not the MTF value of the lens 1 is within the allowable range. If the MTF value of the lens 1 is not within the allowable range, the lens 1 is processed as an NG lens.

  Then, the process proceeds to S22, and it is determined whether or not the measured optical characteristic of the lens 1 is NG. If the measured optical characteristics of the lens 1 are not within the allowable range, it is determined that the lens 1 is NG, and NG count-up processing is performed (S24). In the NG count-up process, the count value for the lens holding position (holding portion 72) on the tray 7 of the lens 1 that has become NG is incremented. This count value is set for each lens holding position for each tray 7 and indicates the number of NG times at each lens holding position.

  And it transfers to S26 and a result display process is performed. The result display process is a process for displaying on the monitor 4 that the measured lens 1 is NG. For example, as shown in FIG. 9, the NG display 41 is displayed as an image. By viewing this display, the operator can easily know that any of the lenses 1 on the tray 7 does not satisfy the optical characteristic reference value.

  At this time, it is preferable to display what kind of NG the lens 1 is in different colors for each NG content. For example, as shown in FIG. 9, a tray display 42 corresponding to the lens holding position of the tray 7 (formation position of the holding portion 72) is displayed, and the coordinates such as A1 and B2 are set as A to F and 1 to 6 in the vertical direction. The value is displayed so that the lens holding position can be specified by the value. In the tray display 42, for example, when the MTF is out of the allowable range and NG, the position of the NG lens 1 is displayed in red, when the FFL is NG, it is displayed in brown, and when the eccentricity is NG. Is displayed in an on-registry color, and is displayed in a pink color when the depth of focus is NG.

  By displaying in different colors for each NG content in this way, it is possible to easily recognize which item NG the optical characteristic of the lens 1 is. In addition, by notifying other persons of the color of NG, information on the NG content of the lens 1 can be easily transmitted. In particular, when the operator of the apparatus conveys NG contents to persons using different languages, the NG contents can be easily transmitted.

  On the other hand, if it is determined in S22 of FIG. 6 that the measured optical characteristic of the lens 1 is not NG, measurement result processing is performed (S28). This result display process is a process for displaying on the monitor 4 that the measured lens 1 is OK instead of NG. For example, as shown in FIG. 10, an OK display 43 is displayed as an image. By viewing this display, the operator can easily know that all the lenses 1 on the tray 7 satisfy the optical characteristic reference value. In addition, when the measured lens 1 is not NG and not OK and the determination is on hold, “hold” may be displayed.

  Then, the process proceeds to S30, and it is determined whether or not the measurement of all the lenses 1 on the tray 7 has been completed. For example, when the position of the tray 7 is moved by operating the XY stage 22 and the lenses 1 on the tray 7 are sequentially measured from the end, whether or not all the lenses 1 on the tray 7 have been measured. Is judged. If all the lenses 1 on the tray 7 have not been measured, the process returns to S18.

  On the other hand, if it is determined in S30 that all the lenses 1 on the tray 7 have been measured, a warning process is performed (S32). The warning process is a process for warning that there is a possibility that there is an abnormality in the lens measurement system when the NG counter value counted up in S24 exceeds a set value. For example, when NG at a specific lens holding position in the tray 7 having the same identification number is NG continuously n times, it is warned that the tray 7 is abnormal. In this case, you may warn when it is NG n times by m times measurement. The warning is performed by displaying an image on the monitor 4, outputting a sound, or emitting light from a light emitting member such as a lamp. On the other hand, if the NG counter value counted up in S24 is not greater than or equal to the set value, the warning process is not performed to warn of abnormality of the lens measurement system. When this warning process is finished, the control process is finished.

  As described above, according to the lens measurement device according to the present embodiment, the type of the lens 1 is detected based on the information given to the tray 7 when the tray 7 holding the lens 1 is disposed at the lens measurement position. Then, the measurement setup of the measurement unit 3 is performed. For this reason, it is not necessary to set the measurement according to the type of the lens 1 to be measured by the operator of the lens measuring apparatus, and the measurement operation can be performed smoothly.

  In addition, since the type of the lens 1 is automatically recognized by arranging the tray 7 at the lens measurement position, it is possible to prevent the wrong setting of the type of the lens 1 from being set.

  In particular, when the optical characteristics of the lens 1 are measured by back projection, it is possible to prevent a situation in which the chart comes into contact with the tray 7 or the lens 1 and is damaged due to an erroneous measurement setting.

  The lens measuring device according to the above-described embodiment is an example of the lens measuring device according to the present invention. The lens measuring device according to the present invention is not limited to the lens measuring device according to these embodiments, and the lens measuring device according to the embodiments is modified or changed without changing the gist described in each claim, or It may be applied to other things.

1 is a schematic configuration diagram of a lens measuring device according to an embodiment of the present invention. It is a top view of the tray used for the lens measuring apparatus in FIG. It is sectional drawing of the tray in III-III of FIG. It is a side view of the tray seen from IV-IV of FIG. It is explanatory drawing of the chart used for the lens measuring apparatus in FIG. It is a flowchart which shows the basic operation | movement of the lens measuring apparatus of FIG. It is explanatory drawing of the measurement result in the lens measuring apparatus of FIG. It is explanatory drawing of the measurement result in the lens measuring apparatus of FIG. It is explanatory drawing of the measurement result display in the lens measuring device of FIG. It is explanatory drawing of the measurement result display in the lens measuring device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens, 2 ... Measurement part, 3 ... Analysis control part, 4 ... Monitor, 5 ... Determination part, 6 ... Power supply part, 7 ... Tray, 23 ... Chart, 24 ... Integrating sphere, 26 ... Camera, 62 ... Vibration isolation Rubber.

Claims (3)

In a lens measuring device that measures the optical characteristics of a lens,
A holder for holding the lens to be measured;
Detecting means for detecting a type of a lens held by the holder based on information attached to the holder when the holder is arranged at a lens measurement position;
Measurement setting means for performing measurement setting of the measurement unit according to the type of the lens detected by the detection means;
A lens measuring device. An apparatus that arranges a chart at a focal position of the lens and measures optical characteristics of the lens by back projection,
The measurement setting means sets the position of the chart according to the type of the lens;
The lens measuring device according to claim 1. The lens measuring device according to claim 1, wherein at least MTF is measured as an optical characteristic of the lens.

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