JP7260120B2 - Pupil lens measuring device and measuring method - Google Patents

Description

The present invention relates to a pupil lens measuring apparatus and method that can be used to measure the principal ray angle and image height of a pupil lens that is used for optical tests of optical devices such as image sensors.

Solid-state imaging devices such as CMOS image sensors, which are semiconductor integrated circuits, are widely used in digital still cameras, video cameras, mobile phones, and various other industrial equipment, taking advantage of their ability to convert light into electrical signals. ing. Solid-state imaging devices require optical tests and operation inspections. For example, as an inspection device for optical devices such as solid-state imaging devices, conventionally, an inspection device with a lens unit mounted on a probe card has been used ( For example, see Patent Document 1). In the conventional inspection equipment, the lens is aligned with the center of the sensor area of the image pickup device, and the probe needle of the probe card is brought into contact with the image pickup device arranged on the wafer. By irradiating an image pickup device and confirming an electric signal from the image pickup device through a probe card, it is inspected whether or not the image pickup device operates normally. In the past, it was common to test image sensors by irradiating them with a parallel beam of light. Since the angle of incidence and the angle of view of the light incident on the image pickup device are increasing along with this, pupil lenses with performance close to real lenses used in digital cameras, etc., are used in lens units, and the inspection target It is becoming important and common to perform inspection by irradiating the imaging device with light having a predetermined tilt angle through a pupil lens.

International Publication No. WO2008/059767

Various types of pupil lenses have been developed for use in the inspection of image pickup devices as described above, for example, those with lens characteristics similar to those of real lenses such as cameras, and those with various lens characteristics. A lens is designed and manufactured by a person based on a simulation of lens characteristics and the like. Since lenses manufactured in recent years are manufactured with extremely high precision due to advances in manufacturing technology, it was thought that it would be rare for the values to deviate significantly from the optical design values. The pupil lens was used to test the image sensor assuming it was performing as (or fairly close to) its optical design values, without any actual measurements being taken. However, along with the increase in density and accuracy of image sensors, and the diversification and improvement in the types of lenses, it is necessary to check whether the performance of the pupil lens used for testing the image sensors is functioning normally. However, it is becoming more and more important to more precisely confirm errors from optical design values. In particular, in the pupil lens used for testing the image sensor as described above, the relationship between the chief ray angle, which is the irradiation angle to the image sensor, and the image height, is compared with the actually measured value and the optical design value. Therefore, there is a strong demand for the development of a measuring apparatus and a measuring method for actually measuring the lens characteristics such as the principal ray angle of the pupil lens.

The present invention has been made in view of the above-described conventional problems, and one of its purposes is, for example, to easily measure the principal ray angle and image height of a pupil lens used for testing an image pickup device and the like, and to An object of the present invention is to provide a pupil lens measuring device and a measuring method capable of evaluating and confirming a lens.

In order to solve the above problems, the present invention provides a movable support portion 12 that supports a pupil lens 100 to be measured so as to be linearly movable along the direction of the optical axis 102 of the pupil lens 100; parallel light illumination means 14 for irradiating parallel light parallel to the optical axis 102 of the pupil lens 100; a pinhole portion 16 illuminated by the parallel light illumination means 14 and imaged by the pupil lens 100; A pinhole distance changing device 18 that can change the vertical distance (y1 to y4) from the optical axis 102 of 100 to the pinhole part 16, and the light that has passed through the pupil lens 100 an observation optical system 20 for confirming L, an image height measuring means 22 for measuring the image height Y of the pinhole portion 16 imaged by the pupil lens 100, and along the optical axis 102 via the movable support portion 12 linearly moving the pupil lens 100 by moving the pupil lens 100 so that the collimated light passing through the pinhole portion 16 converges on the focal point on the optical axis of the pupil lens 100, and the observation optical system 20 confirms the movement position x1 of the pupil lens; distance measuring means 24 for measuring the distance (x1-x2) between the moving position x2 of the pupil lens where the image formation of the pinhole portion 16 by the pupil lens 100 is confirmed by the observation optical system; and a pupil lens measuring device 10.

In this case, it is preferable to include a diffuser plate 56 that can be inserted into and removed from the optical path near the position of the pinhole portion 16 .

Further, the pinhole portion 16 may be set at a predetermined separation position a with respect to the pupil lens 100 and integrally attached to the movable support portion 12 .

Further, the diaphragm 62 may be integrally attached to the movable support portion 12 at a position near the focal length f of the pupil lens 100 .

Further, the pinhole distance changing device 18 includes a pinhole plate 40 provided with a plurality of pinhole portions 16 through which the parallel light from the parallel light illumination means 14 passes, and a slit 43 elongated in the direction orthogonal to the optical axis 102 . is formed and the portion other than the slit is shielded, and the combination of the slit plate 42 assembled face-to-face with the pinhole plate 40, the pinhole portion 16 of the pinhole plate 40 and the slit 43 of the slit plate 42 A selection mechanism 44 that can selectively change the distance of the pinhole portion 16 from the optical axis 102 by changing the position may be included.

Further, the pinhole portion 16 may be provided with pinholes at positions that are line-symmetrical with respect to the optical axis 102 of the pupil lens 100 .

Further, the present invention is a pupil lens measuring method for measuring the principal ray angle θ and the image height Y of the pupil lens 100. The arranged pinhole portion 16 is supported by a movable support portion 12 that is linearly movable along the optical axis direction of the pupil lens 100, and the parallel light from the parallel light illumination means 14 is allowed to pass through the pinhole portion 16. The pupil lens 100 is moved along the optical axis 102 via the movable support portion 12, and the parallel light from the pinhole portion 16 is brought to the focal point on the optical axis by the pupil lens. a step of setting the pupil lens 100 at a movement position x1 where the converged light is confirmed by the observation optical system 20; a step of moving the pupil lens 100 along the axis 102 and setting the pupil lens at a movement position x2 where the observation optical system 20 confirms the image L of the pinhole portion 16 formed by the pupil lens 100; The distance (x1-x2) from the movement position x1 of the pupil lens where the light converged to the upper focus is confirmed to the movement position x2 of the pupil lens where the image formation of the pinhole portion 16 is confirmed is measured by the distance measuring means 24. measuring the image height Y of the image formation of the pinhole portion at the moving position where the image formation of the pinhole portion is confirmed through the image height measurement means; and the image height measurement means The image height Y of the pinhole portion measured by 22 and the distance (x1 −x2), and obtaining the chief ray angle θ of the pupil lens from the value using a trigonometric function.

According to the pupil lens measuring apparatus of the present invention, a movable support section that supports a pupil lens to be measured so as to be linearly movable along the optical axis direction of the pupil lens; A parallel light illumination means for irradiating parallel light parallel to the axis, a pinhole portion illuminated by the parallel light illumination means and imaged by the pupil lens, and a distance on a vertical line from the optical axis of the pupil lens. a pinhole distance changing device capable of changing the vertical distance to the pinhole by using a pinhole, an observation optical system for confirming the light that has passed through the pupil lens, and an image of the pinhole formed by the pupil lens The pupil lens is linearly moved along the optical axis via the image height measuring means for measuring the height, and the parallel light passing through the pinhole portion converges on the focal point on the optical axis of the pupil lens. Measure the distance between the movement position of the pupil lens confirmed by the observation optical system and the movement position of the pupil lens at which the observation optical system confirms the image formation of the pinhole portion by the same pupil lens. Since the distance measuring means is provided, the image height of the image formation of the pinhole portion and the light converged on the focal point on the optical axis of the pupil lens are the same as the movement position of the pupil lens confirmed by the observation optical system. By measuring the distance between the image formation of the pinhole portion by the pupil lens and the moving position of the pupil lens confirmed by the observation optical system, the principal ray angle can be obtained and measured. As a result, by comparing the actually measured values of the principal ray angle and the image height of the pupil lens with the optical design values, it is possible to evaluate and confirm, for example, the pupil lens for testing the image sensor. .

In addition, by including a diffuser plate that can be inserted into and removed from the optical path near the position of the pinhole, the image can be clearly formed, and the position and distance where the image can be confirmed can be measured. It is possible to accurately measure the principal ray angle and the image height.

Further, the pinhole portion is set at a predetermined distance from the pupil lens and integrally attached to the movable support portion, so that the distance between the pupil lens and the pinhole portion is maintained. Even if the pupil lens is moved along the optical axis, there is little change in the light observed by the observation optical system through the pupil lens from the pinhole portion, and measurement can be performed smoothly.

In addition, the diaphragm is integrally attached to the movable support portion near the focal length of the pupil lens, so that even if the pupil lens is moved along the optical axis, There is little change in the light that passes through the pupil lens and is observed by the observation optical system, and it is possible to accurately and smoothly measure the position and distance where the image formation is confirmed.

Further, the pinhole distance changing device includes a pinhole plate provided with a plurality of pinhole portions through which parallel light from the parallel light illumination means passes, and a long slit formed in a direction perpendicular to the optical axis. By changing the combination position of the slit plate that shields the portion other than the slit and is assembled with the pinhole plate in a face-to-face manner, and the pinhole portion of the pinhole plate and the slit of the slit plate, the pinhole portion and a selection mechanism capable of selectively changing the distance from the optical axis, the pinhole distance changing device can be realized with a simple structure, and the vertical distance from the optical axis to the pinhole can be changed. Changes can be made easily, that is, the principal ray angle and image height can be measured smoothly while changing the object height, which is the object distance.

In addition, the pinhole portion has a configuration in which the pinhole is provided at a position that is symmetrical with respect to the optical axis of the pupil lens. , it is easy to confirm the moving position of the pupil lens where the focal point can be confirmed by the observation optical system and the position where the image formation can be confirmed.

Further, according to the pupil lens measuring method of the present invention, it is a pupil lens measuring method for measuring the principal ray angle and the image height of the pupil lens, and the pupil lens to be measured is separated from the optical axis of the pupil lens by a predetermined distance. A pinhole portion arranged at a position is supported by a movable support portion that is linearly movable along the optical axis direction of the pupil lens, and the parallel light from the parallel light illumination means is passed through the pinhole portion to form the pupil lens. , the pupil lens is moved along the optical axis via the movable support, and the collimated light from the pinhole is converged to the focal point on the optical axis by the pupil lens, and the observation optical system setting the pupil lens at the movement position confirmed by the step of placing a diffusion plate in the optical path, moving the pupil lens along the optical axis via the movable support, and forming a pinhole portion by the pupil lens a step of setting the pupil lens at a moving position where the image formation is confirmed by an observation optical system; and a pinhole from the moving position of the pupil lens at which light converged to the focal point on the optical axis of the pupil lens is confirmed. a step of measuring, via a distance measuring means, a distance to a moving position of the pupil lens where the image formation of the pinhole portion is confirmed; The step of measuring the image height via an image height measuring means, and confirming light at the image height of the pinhole portion measured by the image height measuring means and the focal point of the pupil lens measured by the distance measuring means. and a step of determining the principal ray angle of the pupil lens using a trigonometric function from the value of the distance from the movement position to the movement position where image formation is confirmed, and the principal ray angle of the pupil lens and the image The height can be actually measured, and the measured value can be compared with the optical design value to evaluate, confirm, etc. the pupil lens for testing the imaging device.

1 is a schematic explanatory diagram of a pupil lens measuring device according to an embodiment of the present invention; FIG. FIG. 2 is an explanatory view of a slit plate in the AA line view of the pupil lens measuring device of FIG. 1; FIG. 2 is an explanatory view of a pinhole plate in the BB line view of the pupil lens measuring device of FIG. 1; FIG. 2 is an explanatory view of a pinhole distance changing device in the CC line view of the pupil lens measuring device of FIG. 1; 2 is an explanatory diagram of an observation optical system of the pupil lens measuring apparatus of FIG. 1; FIG. 2 is an explanatory view showing a state in which parallel light that has passed through a pupil lens is condensed at a focal point on the optical axis in the pupil lens measuring device of FIG. 1; FIG. 2 is an explanatory diagram showing a state in which light passing through a pupil lens forms an image in the pupil lens measuring device of FIG. 1; FIG. FIG. 2 is a schematic explanatory diagram for obtaining a principal ray angle of a pupil lens with the pupil lens measuring apparatus of FIG. 1; It is an example of a graph showing the relationship between the image height of the pupil lens and the chief ray angle. 2 is an explanatory diagram of another embodiment of the parallel light illumination means of the pupil lens measuring device of FIG. 1; FIG. 2 is an explanatory diagram of another embodiment of the pinhole distance changing device of the pupil lens measuring device of FIG. 1; FIG. FIG. 4 is a schematic explanatory diagram of principal ray angles and image heights of a pupil lens;

An embodiment of a pupil lens measuring apparatus of the present invention will be described below with reference to the accompanying drawings. A pupil lens measuring apparatus and a measuring method according to the present invention are capable of actually measuring the principal ray angle and image height of a pupil lens used for optical testing of an imaging device (image sensor), for example. is. 1 to 12 show an embodiment of the pupil lens measuring device and measuring method of the present invention. FIG. 1 is a schematic explanatory diagram of a pupil lens measuring device 10 of this embodiment. As shown in FIG. 1, a pupil lens measuring apparatus 10 according to the present embodiment includes a movable support portion 12 that movably supports a pupil lens 100 to be measured, a parallel light illumination means 14, a pinhole portion 16, A pinhole distance changing device 18 that changes the distance from the optical axis 102 of the pupil lens 100 to the pinhole portion 16, an observation optical system 20 that observes the light that has passed through the pupil lens 100, an image height measuring means 22, and a movable and distance measuring means 24 for measuring a predetermined moving distance of the pupil lens 100 that moves via the supporting portion 12 . In this embodiment, the pupil lens 100 to be measured has, for example, a diaphragm function, and is provided so as to emit incident light toward an imaging device or the like at a predetermined angle and range. For example, as shown in FIG. 12, the pupil lens measuring device 10 of the present embodiment measures the principal ray angle θ passing through the aperture center of the pupil lens 100 and the formed image height Y, and measures the object height (pinhole In order to measure and confirm the relationship between the principal ray angle θ and the image height Y (see FIG. 9) that changes when the pinhole height y, which is the distance on the vertical line from the optical axis of the part, is changed. An example of use will be explained.

As shown in FIG. 1, the movable support section 12 is a pupil lens support means and a linear movement means for supporting the pupil lens 100 to be measured so as to be linearly movable along the optical axis 102 of the pupil lens 100 . In this embodiment, the apparatus components including the movable support section 12, the parallel light illumination means 14, the pinhole section 16, the pinhole distance changing device 18, the observation optical system 20, the image height measuring means 22, the distance measuring means 24, etc. are , is attached to a base body 26 serving as a base. As shown in FIGS. 1, 6, and 7, the movable support section 12 has, for example, a movable member 28 which is connected to a base body 26 so as to be vertically slidable. Support the lens 100 . The movable support section 12 supports the pupil lens 100 so that the optical axis 102 of the pupil lens 100 and the linear sliding movement direction of the movable member with respect to the base are parallel to each other, and the supported pupil lens 100 is moved along the optical axis 102. and can be held at the moved position. The movable support part 12 has a structure substantially similar to that of a well-known microscope stage, for example, and the movable member moves up and down by manually rotating a knob or the like. The moving mechanism of the movable support part 12 that supports the pupil lens 100 is not limited to a configuration in which the user manually moves the pupil lens 100, but may be configured to move mechanically or electrically by an actuator or the like.

The parallel light illumination means 14 is illumination means for irradiating parallel light parallel to the optical axis of the pupil lens 100 supported by the movable support portion 12 . In this embodiment, in FIG. 1, the parallel light illumination means 14 includes, for example, a light source 30 such as a halogen lamp installed in a lamp house, a light source side diaphragm 32 for limiting the amount and range of light from the light source 30, and the light source 30 and a collimator lens 34 that corrects the light passing through the light source side diaphragm 32 and irradiates it as parallel light. The collector lens 34 is set to emit light parallel to the optical axis 102 of the pupil lens 100 supported by the movable support 12 . Note that the parallel light illumination means 14 is not limited to the aspect of the present embodiment, and may be of any configuration as long as it is configured to irradiate parallel light. For example, FIG. 10 shows another form of the parallel light illumination means 14, which includes a laser light source 36 and a beam expander 38 configured by combining a plurality of lenses (concave lens 38a, convex lens 38b, etc.). The beam expander 38 expands the range of parallel light from the laser light source 36 to irradiate light parallel to the optical axis 102 of the pupil lens 100 supported by the movable support 12 . Also, the parallel light illumination means 14 may be composed of, for example, various light sources, and an arbitrary illumination optical system including a lens, a diaphragm, a half mirror, a pinhole, etc. for converting the light from the light sources into parallel light.

The pinhole portion 16 is a chart means illuminated by the parallel light illumination means 14 and imaged by the pupil lens of the object to be measured. As shown in FIG. 1, in the present embodiment, the pinhole portion 16 is, for example, a small-diameter pinhole formed in a pinhole plate 40, which will be described later, and is separated from the optical axis 102 of the pupil lens 100 by a predetermined distance. The pinhole allows the light from the parallel light illumination means 14 to pass through toward the pupil lens 100, and the portion other than the pinhole blocks the light to form a bright pinhole chart as a point light source. Form. Therefore, the point light source light having a predetermined object height from the optical axis 102 is passed toward the pupil lens 100 . The pinhole part 16 is installed, for example, in the optical path at a position between the parallel light illumination means 14 and the pupil lens 100 to be measured, and is movably supported by being set at a predetermined separation position a with respect to the pupil lens 100. It is integrally attached to the portion 12 . Therefore, the pupil lens 100 and the pinhole portion 16 can move integrally along the optical axis 102 of the pupil lens 100 via the movable support portion 12 while holding the predetermined separation position a. Further, the pinhole portion 16 is provided at a position symmetrical with respect to the optical axis 102 of the pupil lens 100 with the optical axis as the symmetrical axis. A set of pinholes is formed. The pinhole part 16 is provided so that the distance from the optical axis 102 can be changed by the pinhole distance changing device 18 . Note that the pinhole portion 16 may not be provided integrally with the movable support portion 12 . For example, the pinhole portion 16 and the pupil lens 100 may be fixedly or movably supported so that the distance between the pinhole portion 16 and the pupil lens 100 can be close or separated.

The pinhole distance changing device 18 can change the vertical distance from the optical axis of the pupil lens to the pinhole, that is, the distance (height) from the optical axis of the pinhole. It is pinhole distance changing means. In this embodiment, for example, as shown in FIGS. 2, 3, and 4, the pinhole distance changing device 18 includes a pinhole plate 40 provided with a plurality of pinhole portions 16 and a slit 43 formed therein. It has a slit plate 42 and a selection mechanism 44 capable of selectively changing the combination of the pinhole portion 16 of the pinhole plate 40 and the slit 43 of the slit plate 42 .

As shown in FIG. 3, the pinhole plate 40 is, for example, a circular plate, the plate surface of which is set perpendicular to the optical axis 102 of the pupil lens, and the center of which is set to the optical axis 102. A plurality of pinhole portions 16 are provided at different distance positions y1 to y4 from the center of the plate, that is, the optical axis . In the present embodiment, the pinhole portions 16 of the pinhole plate 40 are provided in four pairs at different distances y1 to y4, with two pinhole portions 16 having the same distance 180 degrees across the center. The pinhole portions 16 at different distances from the optical axis 102 of the pinhole plate 40 are set at positions shifted by a predetermined rotation angle in the circumferential direction and are not arranged on the same straight line passing through the center. As shown in FIG. 2, the slit plate 42 is, for example, a circular plate having approximately the same size as the pinhole plate 40. The plate surface is set perpendicular to the optical axis 102 of the pupil lens, Its center is set to the optical axis 102, and a long slit 43 is formed in the center in a direction orthogonal to the optical axis 102. As shown in FIG. The slit 43 of the slit plate 42 is, for example, an elongated hole extending in the radial direction through the center of the plate. is designed to block light. For example, the slit plate 42 is arranged in a face-to-face manner so as to substantially abut or be close to the plate surface of the pinhole plate 40 on the side of the parallel light illumination means 14 , and only the linear light that has passed through the slit 43 is pinhole-shaped. The plate 40 is illuminated. As shown in FIGS. 4(a) and 4(b), the selection mechanism 44 is centered on the pinhole plate 40 and the slit plate 42 which are arranged face-to-face with their centers aligned on the optical axis 102, for example. By rotating at least one of the pinhole plate 40 and the slit plate 42 around the rotary shaft 45, that is, around the optical axis, any one of the pinhole plates 40 can be rotated. As a result of selectively changing the position of the slit 43 of the slit plate 42 to the position of the slit 43 of the slit plate 42, the distance from the optical axis 102 of the pinhole 16 through which the parallel light from the parallel light illumination means 14 passes can be easily adjusted. can be changed to Note that the pinhole distance changing device 18 is not limited to the aspect of the present embodiment, and may have any configuration as long as it can change the distance from the optical axis 102 to the pinhole portion 16 . For example, a pinhole plate having a plurality of pinhole portions may be slid with respect to the slit plate to change the distance of the pinhole portions from the optical axis. Further, for example, as shown in FIG. 11 , the pinhole distance changing device 18 may be configured to change the distance from the optical axis 102 to the pinhole portion 16 by sliding the pinhole portion 16 . In the embodiment of FIG. 11, the pinhole distance changing device 18 slides, for example, a set of two pinhole members 48 having the pinhole portion 16 toward and away from the optical axis 102 via the slide device 46 . freely assembled. As shown in FIGS. 11A and 11B, the slide device 46 has, for example, a pinhole member 48 slidably arranged along a long hole 52 linearly provided in a base 50, and a tip end thereof. is connected to the pinhole member 48, and the two pinhole members 48 are kept at the same distance from the optical axis 102 by the link mechanism 54 in which the link rod is assembled in an X shape via a pivot shaft. It is provided so that it can be slid to change the distance from the optical axis of the pinhole portion 16 . Of course, light other than the pinhole portion is blocked. For example, in the long hole 52 portion of the base 50, along with the pinhole member 48, bellows 49a, 49b, and 49c that are light shielding and expandable are installed. Corresponding to the sliding movement of the pinhole member 48, the bellows 49a, 49b, and 49c expand and contract to always shield areas other than the pinhole portion.

In this embodiment, as shown in FIGS. 1, 6, and 7, a diffusion plate 56 that can be inserted into and removed from the optical path is arranged near the pinhole portion 16 formed by the pinhole plate 40. ing. The diffusion plate 56 is arranged, for example, substantially in contact with or close to the plate surface of the pinhole plate 40 on the pupil lens 100 side, and can diffuse the parallel light passing through the pinhole portion 16 . Since the light from the pinhole portion 16 is diffused in the state where the diffusion plate 56 is arranged, it is possible to confirm the image formation of the pinhole portion 16 by the pupil lens 100 with the observation optical system 20 .

The observation optical system 20 is observation means for confirming light that has passed through the pupil lens 100 to be measured. As shown in FIGS. 1 and 6, in the present embodiment, the observation optical system 20 is configured, for example, so that the observer directly confirms the light that has passed through the pupil lens 100 with his/her eyes E. It consists of a magnifying optical system including an objective lens 58 arranged on the side and an eyepiece lens 60 arranged on the observer's eye side. 6 and 7 schematically show the eye E of the measurer. Also, for the sake of explanation, the optical path is shown in a simplified form. The observation optical system 20 is mounted on, for example, the base body 26 , and moves relatively close to and away from the pupil lens 100 supported by the movable support section 12 by linear movement of the pupil lens 100 . 5(a) and 5(b) are explanatory views of the observing optical system 20. The pupil lens 100 linearly moves along the optical axis 102 with respect to the observing optical system 20 to approach the observing optical system 20. , or apart, the light L from the pupil lens 100 observed by the observation optical system 20, that is, the position where the pinhole image can be seen, moves, comes into focus, or goes out of focus. For the objective lens 58 and the eyepiece lens 60 of the observation optical system 20, for example, an objective lens and an eyepiece lens used in a well-known microscope can be used, and the image is magnified by a predetermined magnification. That is, as shown in FIG. 7, the light L appearing when looking through the eyepiece lens 60 observes an enlarged image L1 enlarged by the magnification of the objective lens and an enlarged image L2 enlarged by the magnification of the eyepiece lens 60. It will be done. The objective lens 58 and the eyepiece lens 60 are set such that their optical axes coincide with the optical axis of the pupil lens 100 to be measured. Also, the eyepiece 60 is composed of, for example, a micrometer eyepiece having a scale display, and constitutes image height measuring means 22, which will be described later. Note that the observation optical system 20 is not limited to the configuration described above, and may have a configuration in which predetermined lenses, sensors, etc. are combined, or any other configuration. For example, the observation optical system 20 is provided with an imaging device such as a camera having an imaging device such as a CMOS or an optical sensor at the image plane position of the light that has passed through the pupil lens 100. It is also possible to check the captured image on a monitor or the like, or to check the light while measuring the intensity of received light.

In this embodiment, as shown in FIG. 1, an aperture stop 62 is arranged near the focal length f on the image side of the pupil lens 100 to be measured. Since the focal position f of the pupil lens 100 is equal to the exit pupil of the pupil lens, it can be said that the aperture stop 62 is installed in the vicinity of the exit pupil position. The aperture stop 62 is, for example, integrally attached to the movable support portion 12 and moves along the optical axis 102 together with the pupil lens 100 while being held at a position near the focal length f of the pupil lens 100 . Since the aperture stop 62 is placed near the focal length f of the pupil lens 100, even if the distance between the pupil lens 100 and the objective lens 58 changes, the light L passing through the pupil lens 100, that is, the pinhole image The size of is hard to change and is easy to observe.

The image height measuring means 22 is means for measuring the image height Y of the pinhole portion 16 imaged by the pupil lens 100 . In the present embodiment, as shown in FIG. 5, the image height measuring means 22 uses, for example, a scale display provided on an eyepiece lens 60 (micrometer eyepiece lens) of the observation optical system 20 and a pinhole passing through the pupil lens 100. By comparing the light (image) L from the part, the image height Y can be visually measured by the measurer. Note that the image height measuring means 22 is not limited to the one described above, and may have any other configuration. For example, the image height measuring means 22 may have a translucent scale plate installed at the image plane position in the optical path. For example, when the observation optical system 20 uses an imaging device such as a camera, the image height measurement means 22 measures the image height by reading the coordinates and scale from the image displayed on the monitor, or The image height may be measured by arithmetic processing such as a computer.

When the distance measuring means 24 linearly moves the pupil lens 100 along the optical axis 102 via the movable support part 12, parallel light passing through the pinhole part 16 converges on the focal point of the pupil lens 100 on the optical axis. A movement position x1 (see FIG. 6) of the pupil lens 100 where the light L projected by the observation optical system 20 is confirmed, and an image formation of the pinhole portion 16 by the pupil lens 100 is confirmed by the observation optical system 20. It is distance measuring means for measuring the distance (x1-x2) between the movement position x2 (see FIG. 7) of the pupil lens 100 and the distance. In this embodiment, as shown in FIG. 6, the pupil lens 100 is moved, and the parallel light that has passed through the pinhole portion 16 converges on the focal point of the pupil lens 100 on the optical axis. The movement position x1 of the pupil lens 100 confirmed by 20 is called a focus confirmation movement position x1. On the other hand, as shown in FIG. 7, by moving the pupil lens 100, the movement position x2 of the pupil lens 100 at which the image formation of the pinhole portion 16 by the pupil lens 100 is confirmed by the observation optical system 20 is determined. This is referred to as an image confirmation position x2. As shown in FIG. 1, the distance measuring means 24 is, for example, a scale display provided on the base body 26, which can measure the movement position of the movable member 28 of the movable support portion 12 that supports the pupil lens 100. Including display. The distance measuring means 24 reads, for example, the scale display of the focus confirmation movement position x1 and the scale display of the imaging confirmation position x2, respectively, and the difference between them (x1-x2 (or x2-x1)). is measured by calculating Note that the distance measuring means 24 is not limited to the above configuration, and may have any configuration as long as it can measure the distance between the focus confirmation movement position x1 and the imaging confirmation position x2.

Next, the operation of the pupil lens measuring apparatus 10 according to this embodiment and the pupil lens measuring method will be described. For example, when the optical design values of the pupil lens are as shown in the graph of FIG. 9, the principal ray angle θ and the image height Y of the same pupil lens are actually measured while changing the object height. Then, it is confirmed whether or not the measured value is the same as the optical design value in FIG. The pupil lens 100 to be measured is supported by the movable support portion 12 of the pupil lens measuring device 10, and the parallel light from the parallel light illumination means 14 is passed through the pinhole portion 16 and irradiated toward the pupil lens 100. back. First, the pinhole distance changing device 18 is set so that the light passes through the pinhole portion 16 at a predetermined distance (for example, y1) from the optical axis 102 . As shown in FIG. 1, with the diffuser plate 56 removed from the optical path, the observer checks the light passing through the pupil lens 100 with the observation optical system 20 and moves the pupil lens 100 through the movable support 12. along the optical axis. As shown in FIGS. 5A and 6, the pupil lens 100 is moved, and the parallel light from the pinhole portion 16 is converged to the focal point on the optical axis by the pupil lens, and the light L is confirmed by the observation optical system 20. The position of the pupil lens is set to the focus confirmation movement position x1. At this time, the focus check movement position x1 is measured using the scale of the distance measuring means 24. FIG. Next, as shown in FIG. 7, a diffusion plate 56 is inserted into the optical path. With the diffusion plate 56 inserted, the pupil lens is moved along the optical axis via the movable support 12, and as shown in FIGS. is formed, and the position of the pupil lens is set at the image formation confirmation movement position x2 where the observation optical system 20 confirms that the image is in focus. At this time, the image height Y of the image formed on the pinhole portion (the image formed by the light passing through the pinhole portion) is measured through the scale display of the image height measuring means 20 . In the present embodiment, the observation optical system 20 is magnified and displayed by the objective lens and the eyepiece, and at the same time, the scale display of the micrometric eyepiece is used for visual measurement. The actual image formation height Y is measured by dividing the magnification of the objective lens and the magnification of the eyepiece lens by the respective magnifications from the scale display measured by looking at . Further, the image formation confirming movement position x2 is measured using the scale of the distance measuring means 24. FIG. Then, the distance (x1-x2) from the focus confirmation movement position x1 to the image formation confirmation movement position x2 is obtained from the measured pupil lens focus confirmation movement position x1 and image formation confirmation movement position x2. to measure. As shown in FIG. 8, the image height Y of the light that has passed through the pinhole portion, the distance (x1-x2) from the focus confirmation movement position x1 to the image formation confirmation movement position x2, and the aperture center of the pupil lens 100 Since the trigonometric function tan θ=Y/(x1−x2) is established between the principal ray angle θ and , the value of the trigonometric function tan θ is calculated to obtain the principal ray angle θ of the pupil lens. (step S22). Next, the distance (object height) of the pinhole portion 16 from the optical axis 102 is changed via the pinhole distance changing device 18 . The same operation as described above is repeated, and while changing the distance from the optical axis 102 of the pinhole portion, the image height Y and the chief ray angle θ are measured a predetermined number of times, and the chief ray angle of the optical design value shown in FIG. The lens characteristics of the actual pupil lens can be confirmed by comparing with the graph of the relationship with the image height.

The pupil lens measuring apparatus of the present invention described above is not limited to the configuration of the above-described embodiment only, and can be arbitrarily modified without departing from the essence of the present invention described in the claims. good too.

The pupil lens measuring apparatus and measuring method of the present invention can be used, for example, to actually measure the relationship between the chief ray angle and the image height of a pupil lens used for testing an image sensor.

10 Pupil Lens Measuring Device 12 Movable Supporting Part 14 Parallel Light Illumination Means 16 Pinhole Part 18 Pinhole Distance Changing Device 20 Observation Optical System 22 Image Height Measuring Means 24 Distance Measuring Means 40 Pinhole Plate 42 Slit Plate 44 Selection Mechanism 46 Slide Device 56 diffusion plate 100 pupil lens 102 optical axis of pupil lens θ chief ray angle

Claims (7)

a movable support that supports the pupil lens to be measured so as to be linearly movable along the optical axis direction of the pupil lens;
parallel light illumination means for illuminating parallel light parallel to the optical axis of the pupil lens supported by the movable support;
a pinhole portion illuminated by the parallel light illumination means and imaged by the pupil lens;
a pinhole distance changing device capable of changing the perpendicular distance from the optical axis of the pupil lens to the pinhole portion;
an observation optical system for confirming light that has passed through the pupil lens;
image height measuring means for measuring the image height of the pinhole portion imaged by the pupil lens;
The pupil lens is linearly moved along the optical axis via the movable support, and the parallel light passing through the pinhole portion converges on the focal point of the pupil lens on the optical axis, and the pupil is confirmed by the observation optical system. a distance measuring means for measuring a distance between a moving position of the lens and a moving position of the pupil lens at which the observation optical system confirms the image formation of the pinhole portion by the same pupil lens. A pupil lens measuring device characterized by: 2. A pupil lens measuring apparatus according to claim 1, further comprising a diffuser plate which can be inserted into and removed from the optical path near the position of the pinhole. 3. The pupil lens measuring apparatus according to claim 1, wherein the pinhole section is set at a predetermined distance from the pupil lens and integrally attached to the movable support section. 4. A pupil lens measuring apparatus according to claim 1, wherein a diaphragm is integrally assembled with the movable support portion at a position near the focal length of the pupil lens. The pinhole distance changing device includes a pinhole plate provided with a plurality of pinhole portions for passing parallel light from the parallel light illumination means,
a slit plate having a long slit formed in a direction perpendicular to the optical axis, shielding the portion other than the slit from light, and assembled face-to-face with the pinhole plate;
a selection mechanism capable of selectively changing the distance from the optical axis of the pinhole portion by changing the combination position of the pinhole portion of the pinhole plate and the slit of the slit plate. A pupil lens measuring device according to any one of claims 1 to 4. 6. The pupil lens measuring apparatus according to claim 1, wherein the pinhole portion is provided at a position symmetrical with respect to the optical axis of the pupil lens. A pupil lens measurement method for measuring the chief ray angle and image height of a pupil lens,
A pupil lens to be measured and a pinhole portion arranged at a predetermined distance from the optical axis of the pupil lens are supported by a movable support portion that is linearly movable along the optical axis direction of the pupil lens. Parallel light from the illumination means passes through the pinhole portion and is irradiated toward the pupil lens,
The pupil lens is moved along the optical axis via the movable support portion, and the parallel light from the pinhole portion is converged by the pupil lens to the focal point on the optical axis, and the light is confirmed by the observation optical system. setting a pupil lens;
A diffusing plate is placed in the optical path, the pupil lens is moved along the optical axis via the movable support, and the pupil is moved to a position where the image formation of the pinhole portion by the pupil lens is confirmed by the observation optical system. setting the lens;
The distance from the movement position of the pupil lens where the light converged on the optical axis of the pupil lens is confirmed to the movement position of the pupil lens where the image formation of the pinhole portion is confirmed is measured by the distance measuring means. a step of measuring;
measuring the image height of the image formation of the pinhole portion at the moving position where the image formation of the pinhole portion is confirmed, using an image height measuring means;
The image height of the pinhole portion measured by the image height measuring means, and the distance from the movement position where the light is confirmed to the focus of the pupil lens to the movement position where the image formation is confirmed, measured by the distance measurement means. and determining a principal ray angle of the pupil lens using a trigonometric function from the values.

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