JP2008158125A - Lens unit centering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost and compact lens unit centering device having high environmental resistance and high-versatility, capable of quantitatively measuring the decentering state of a lens unit and adjusting the decentering amount of the lens unit within the desired decentering amount without requiring a master lens. <P>SOLUTION: The lens unit centering device 1 for adjusting the decentering amount of the lens unit to be inspected 20 composed of a plurality of lenses including an adjusting lens 21 within the desired range by moving the adjusting lens 21 related to the lens unit to be inspected 20, includes a first collimator lens 10 for converting a light beam emitted from a point light source device 9 to a collimated luminous flux; the lens unit to be inspected 20 that receives the collimated luminous flux emitted from the first collimator lens 10 through the object side thereof and condenses the light; a second collimator lens 11 disposed so that a focus thereof may be positioned near the focus on the image side of the lens unit 20; a measuring unit 3 for detecting the light beam converted to the collimated luminous flux by the second collimator lens 11 and then, calculating the decentering amount of the lens unit to be inspected 20; and an analysis apparatus 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a centering device that adjusts an adjustment lens to the best position from the amount of transmission eccentricity of a lens unit.

  In a lens unit such as a camera lens composed of a plurality of lenses, the center of the curved surface of each lens is ideally aligned on the optical axis. The eccentricity resulting from the processing error of the lens curved surface occurs. Since the decentering in such a lens unit is a cause of a decrease in optical performance, a predetermined lens (this lens is called an “adjusting lens”) is shifted (moved in a plane perpendicular to the optical axis). Or tilting (tilting with respect to the optical axis) and adjusting so as to obtain a desired imaging state (see, for example, Patent Document 1). An apparatus (alignment apparatus) that performs such adjustment incorporates a test lens unit in an adaptive optics system called a master lens, forms a pinhole image with the master lens and the lens target lens unit, and generates a point image. From the shape, the eccentric state was visually confirmed on a monitor, and adjustment was performed by an adjustment lens in the lens unit to be tested so that the point image was the best. In such an adjustment method, the master lens has a large aberration such as spherical aberration in a single lens unit to be detected, and an optical system that cancels the same optical system as the optical unit or the aberration component of the lens unit to be detected when the decentered component cannot be detected. It was necessary to use.

JP 2000-352647 A

  However, the confirmation of the point image by visual inspection has a problem that the variation among workers is large and the quality is not stable. There is also a problem that variations due to manufacturing errors of the master lens and positioning errors between the master lens and the lens unit to be measured increase. Furthermore, recent lens units such as camera lenses are increasingly required to be smaller and have a higher magnification. To meet these requirements, a low-cost, environment-resistant, compact and highly versatile alignment device is required. It is necessary to measure the eccentric state quantitatively by using it, but there is a problem that there is no such means at present.

  The present invention has been made in view of such a problem, does not require a master lens, can quantitatively measure the eccentric state of the lens unit and can be adjusted within a desired amount of eccentricity, and at a low cost. An object of the present invention is to provide a lens unit alignment device that has high environmental resistance, is small, and satisfies high versatility.

  In order to solve the above-described problem, a lens unit alignment device according to the present invention moves an adjustment lens to a test lens unit including a plurality of lenses including an adjustment lens. A device that adjusts the amount of eccentricity within a desired range, a first collimator lens that converts a light beam emitted from a point light source (for example, the point light source device 9 in the embodiment) into a parallel light beam, and a first collimator lens A test lens unit that collects the emitted parallel light flux by entering from the object side, a second collimator lens disposed so that the focal point is located in the vicinity of the focus on the image side of the test lens unit, and the second A detection device that detects a light beam converted into a parallel light beam by a collimator lens and calculates the amount of eccentricity of the lens unit to be measured (for example, the measurement unit in the embodiment) And a from analyzer 15).

  In such a lens unit aligning device according to the present invention, the detection device includes a microlens array having a plurality of microlenses arranged two-dimensionally, and a point image formed by each of the plurality of microlenses. It is composed of an image sensor to be detected, and an analyzer that calculates the wavefront aberration of the lens unit to be detected from the position of the point image detected by the image sensor and calculates the amount of decentration from the coma component of the wavefront aberration. Is preferred.

  In addition, the lens unit alignment device according to the present invention includes an adjustment device (for example, the alignment stage 16 and alignment claw 17 in the embodiment) that moves the adjustment lens, and the analysis device calculates the calculated eccentricity. It is preferable that the eccentricity of the lens unit is adjusted by moving the adjustment lens by controlling the operation of the adjustment device according to the amount.

  When the lens unit aligning device according to the present invention is configured as described above, a master lens is not required, and there is no movable part in the measurement of the amount of eccentricity, and there is no influence of fluctuation of light rays. Therefore, the environmental resistance can be improved, and the amount of eccentricity of the lens unit to be measured can be measured with high accuracy and quantitatively. Furthermore, since the measurement is simple, the alignment work can be performed in a short time. In addition, by using the Shack-Hartmann principle, it is possible to measure with a white light source, enabling inspection using illumination light having the same wavelength as that of the lens unit used, and miniaturization possible. Thus, it is possible to provide a highly accurate and inexpensive lens unit alignment device.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The lens unit alignment apparatus according to the present invention (hereinafter referred to as “alignment apparatus”) measures the wavefront aberration of the wavefront (transmission wavefront) that has passed through the lens unit to be measured, and calculates its coma component. This is a device that adjusts the amount of eccentricity within a desired range by measuring the amount of eccentricity of the lens unit to be tested and adjusting the adjusting lens in the lens unit to be tested based on the measurement result. The alignment device 1 is configured by arranging an illumination unit 2, a lens unit 20 to be measured, and a measurement unit 3 in this order on an optical axis that extends vertically in FIG. 1. The test lens unit 20 is configured by holding a plurality of lenses including an adjustment lens 21 in a lens barrel 22.

  In the illumination unit 2, a point light source device 9 including a reflecting mirror 4, a light source 5, a diffusion plate 6, a condenser lens 7, and a chart plate 8, and a first collimator lens 10 are arranged in this order on the optical axis. Consists of. The measurement unit 3 includes a second collimator lens 11, a microlens array 12, and an image sensor 13 arranged in this order on the optical axis. The alignment device 1 is provided with a lens unit mount 14 for fixing and holding the placed lens unit 20 to be tested. The lens unit 20 is directed to the illumination unit 2 with the object side facing the illumination unit 2. Fixed to the lens unit mount 12. The measurement unit 3 is configured to be movable on the optical axis, and is adjusted so that the focal point of the second collimator lens 11 substantially coincides with the focal point of the lens unit 20 on the image side.

  A light beam emitted from the light source 5 is directly or reflected by the reflecting mirror 4 and applied to the diffusion plate 6, and passes through the diffusion plate 6 to be a light beam with uniform illuminance. Then, the light is condensed by the condenser lens 7 and applied to the chart plate 8. A pinhole is formed in the chart plate 8 so as to include the optical axis, and a light beam emitted from the pinhole is converted into a parallel light beam by the first collimator lens 10, and from the object side of the lens unit 20 to be measured. Incident. As described above, since the focal point on the image side of the test lens unit 20 is substantially coincident with the focal point of the second collimator lens 11, the light beam emitted from the image side of the test lens unit 20 is once imaged. Thereafter, the light enters the second collimator lens 11 and is converted into a parallel light beam, and this parallel light beam enters the microlens array 12. The microlens array 12 is a lens assembly in which a plurality of fine lenses (microlenses) are two-dimensionally arranged, and light beams that have passed through each microlens are image pickup devices arranged on the focal plane of each microlens. 13 is imaged as each point image. An analysis device (PC) 15 is connected to the image pickup device 13, and an image signal output from the image pickup device 13 is analyzed by the analysis device 15.

  The illumination unit 2 and the measurement unit 3 are examples of a transmission wavefront measurement optical system based on the Shack-Hartmann principle. By detecting the position of each point image formed on the image sensor 13 by the microlens array 12. The wavefront aberration can be calculated by the analysis device 15. The analysis device 15 is configured to measure the amount of decentration of the lens unit 20 to be measured by calculating a coma component from the obtained wavefront aberration. The position serving as a reference for each point image formed by the microlens array 12 is obtained by converting the parallel light beam emitted from the illumination unit 2 with the lens unit 20 and the second collimator lens 11 removed. In this state, the amount of decentration of the lens unit 20 to be measured can be accurately measured by performing this measurement in advance and storing it in the analysis device 15.

  The centering device 1 is provided with a centering stage 16 above the lens unit 20 to be tested, and a centering claw 17 protruding downward from the lower part of the centering stage 16 has a centering claw 17 to be tested. The adjustment lens 21 of the lens unit 20 is held. The alignment stage 16 is configured to be movable in a plane orthogonal to the optical axis, and the alignment lens 16 of the test lens unit 20 can be moved by moving the alignment stage 16. The operation of the alignment stage 16 is controlled by the analysis device 15. Therefore, the analyzing device 15 is configured to adjust the eccentric amount of the lens unit 20 to be measured within a desired range by moving the alignment stage 16 and moving the adjustment lens 21 based on the measured eccentric amount. Has been. The analysis device 15 may calculate the moving direction and distance of the alignment stage 16 from the measured eccentricity, and may operate the alignment stage 16 based on the calculated value, or constantly monitor the eccentricity. Then, the centering stage 16 may be moved and adjusted so that the eccentric amount is fed back to be within a desired range.

  An ultraviolet curable resin is filled between the lens barrel 22 of the lens unit 20 to be tested and the adjustment lens 21. Therefore, when the adjustment of the eccentric amount is completed by the above-described processing, the UV irradiation unit 18 is disposed between the alignment stage 16 and the illumination unit 2 to irradiate the adjustment lens 21 with ultraviolet light, and UV curable resin. Is solidified to fix the adjustment lens 21 to the lens barrel 22. In addition to fixing with an ultraviolet curable resin, the adjustment lens 22 may be fixed with a screw attached to the lens barrel 22.

  As described above, the alignment apparatus 1 according to the present embodiment uses a transmission wavefront measuring optical system based on the Shack-Hartmann principle, so that it is not necessary to use a special light source such as a laser beam. Since it can be measured by a white light source (light source 5) such as a tungsten lamp, it is possible to inspect using illumination light having the same wavelength (white light) as the use state of the lens unit 20 (for example, a camera lens). In addition, it is possible to provide a centering device 1 that can be miniaturized and that is highly accurate and inexpensive. Furthermore, by using the Shack-Hartmann principle, there is no need for a master lens, and there is no moving part in the measurement of the amount of eccentricity, and it is not affected by fluctuations in the light beam. The amount of decentering of the lens unit 20 to be measured can be measured with high accuracy and quantitatively. Furthermore, since the measurement is simple, the alignment work can be performed in a short time.

It is explanatory drawing which shows the structure of the lens unit aligning apparatus which concerns on this invention.

Explanation of symbols

1 Lens unit alignment device 3 Measurement unit (detection device)
9 Point light source device (point light source)
DESCRIPTION OF SYMBOLS 10 1st collimator lens 11 2nd collimator lens 12 Micro lens array 13 Image pick-up element 15 Analysis apparatus (detection apparatus)
16 Alignment stage (adjustment device)
17 Alignment claw (Adjustment device)
20 Lens unit 21 Adjustment lens

Claims (3)

A lens unit aligning device for adjusting a decentering amount of a lens unit within a desired range by moving the adjustment lens with respect to a test lens unit including a plurality of lenses including an adjustment lens. ,
A first collimator lens that converts a light beam emitted from a point light source into a parallel light beam;
The lens unit to be tested that collects the collimated light beam emitted from the first collimator lens by entering from the object side; and
A second collimator lens arranged so that the focal point is located near the focal point on the image side of the lens unit to be examined;
A lens unit alignment apparatus comprising: a detection device that detects a light beam converted into a parallel light beam by the second collimator lens and calculates the amount of eccentricity. The detection device is
A microlens array having a plurality of microlenses arranged two-dimensionally;
An image sensor for detecting a point image formed by each of the plurality of microlenses;
2. The analyzer according to claim 1, further comprising: an analysis device that calculates a wavefront aberration of the lens unit to be detected from a position of a point image detected by the image sensor and calculates the decentering amount from a coma component of the wavefront aberration. Lens unit alignment device. An adjustment device for moving the adjustment lens;
The analysis device is configured to adjust the eccentric amount of the lens unit by moving the adjustment lens by controlling the operation of the adjusting device according to the calculated eccentric amount. The lens unit aligning device according to 1.

Images