KR20210086222A - Imaging lens apparatus and optical coherence tomography system including the imaging lens apparatus - Google Patents

Abstract

The present invention relates to an imaging lens arrangement and an optical coherence tomography system including the same, and more specifically, to an imaging lens arrangement for imaging the surface of an object, and to an optical coherence tomography system in which the imaging lens arrangement is coupled with an optical coherence tomography device for taking tomography up to a predetermined depth of an object. According to the present invention, provided is a system which provides a tomographic image and a surface image of an object by combining, into a single system, an optical coherence tomography imaging device and a surface imaging device using separate light sources in one system. In addition, in the imaging lens arrangement for transferring a surface image to an image sensor, by means of a method for arranging a number of lenses having a specific curvature and thickness at a specific position, even the light passing through an edge of the lens can be used to form a clear, distortion-free image, and the maximum incident light efficiency can be secured.

Description

Imaging lens arrangement and optical coherence tomography system having the same

The present invention relates to an imaging lens assembly and an optical coherence tomography imaging system having the same, and more particularly, to an imaging lens assembly for photographing the surface of an object, and a tomography between the imaging lens assembly and a predetermined depth of the object It relates to an optical coherence tomography imaging system combined with an optical coherence tomography device for imaging.

Conventional optical coherence tomography imaging apparatus showed a tomographic image of an object up to a certain depth. However, when it is necessary to view the surface image of the object in addition to the tomography image, the optical coherence tomography imaging device and the surface imaging device have different wavelengths of light sources, so a surface imaging device must be separately provided in addition to the optical coherence tomography imaging device. there was a problem with

In addition, in the case of a conventional objective lens used in a surface imaging device, a light-passing region for forming an effective image is limited to a partial region with respect to the central axis of the lens. That is, since light passing through a region near the edge of the lens does not form a clear image, only a partial region of the center of the lens is used, and thus, there is a problem in that incident light is relatively reduced.

US 10-2014-0097727 A

The present invention was devised to solve such a problem, and combines an optical coherence tomography imaging device and a surface imaging device using separate light sources in one system into a single system to simultaneously display a tomography image and a surface image of an object. The purpose is to provide a system that provides

In addition, in the imaging lens array that transmits the surface image to the image sensor, by arranging a plurality of lenses having a specific curvature and thickness at a specific position, even the light passing through the edge of the lens is used to produce a clear image without distortion of the image. Another object of the present invention is to provide an imaging lens arrangement that ensures maximum incident light efficiency while forming an image.

In order to achieve the above object, the lens arrangement for acquiring a surface image of an object according to the present invention includes a first lens, a second lens, a beam splitter, a third lens, a fourth lens, a fifth lens, and a second lens arranged sequentially. 6 A lens, an IR Filter, and an iris disposed between the beam splitter and a third lens, wherein the target object side of each lens is referred to as the front side and the focal plane side side is referred to as the rear side, the second lens The front and rear surfaces of the first lens, the front surface of the second lens, the front surface of the third lens, the front and rear surfaces of the fourth lens, the front surface and the rear surface of the fifth lens and the rear surface of the sixth lens have a positive radius of curvature. The rear surface of the second lens, the rear surface of the third lens, the rear surface of the fifth lens, and the front surface of the sixth lens are formed to have a negative radius of curvature, the front and rear surfaces of the beam splitter; The front and rear surfaces of the IR Filter are formed to have an infinite radius of curvature as a plane.

The first lens has a thickness on the central axis of 1.00, a radius of curvature of the front surface of 12.380, and a radius of curvature of the rear surface of 8.080, and the second lens has a thickness of 1.52 on the central axis, a radius of curvature of the front surface of 17.290, and a radius of curvature of the rear surface of the first lens. The radius of curvature is -70.580, the beam splitter has a thickness of 1.26 on the central axis, and the radius of curvature of the front and rear surfaces is infinite, and the third lens has a thickness of 1.09 on the central axis, a radius of curvature of the front of 6.860, and the rear of the beam splitter. has a radius of curvature of -16.980, the fourth lens has a thickness on the central axis of 1.00, a front radius of curvature of 15.940, and a rear radius of curvature of 5.000, and the fifth lens has a thickness of 1.50 on the central axis and a front surface has a radius of curvature of 5.000, a radius of curvature of the rear surface is -14.280, the sixth lens has a thickness on the central axis of 1.23, a radius of curvature of the front surface is -5.000, a radius of curvature of the rear surface is 7.210, and the IR Filter is the center The thickness on the axis is 1.00, the radius of curvature of the front and rear surfaces is infinite, the distance on the central axis between the rear surface of the first lens and the front surface of the second lens is 0.52, and the rear surface of the second lens and the front surface of the beam splitter The distance on the central axis between the beam splitters is 6.87, the distance on the central axis between the rear surface of the beam splitter and the stop is 6.87, the distance on the central axis between the stop and the front surface of the third lens is 0.00, and the rear surface of the third lens The distance on the central axis between the front surface of the fourth lens is 0.44, the rear surface of the fourth lens and the front surface of the fifth lens are in contact without a spaced interval, and the central axis between the rear surface of the fifth lens and the front surface of the sixth lens The distance between the images may be 0.78, the distance on the central axis between the rear surface of the sixth lens and the front surface of the IR Filter may be 3.01, and the distance on the central axis between the rear surface of the IR Filter and the focal plane may be 0.992, and the The unit of the numerical value is millimeters (mm).

The Clear Aperture of the front surface of the first lens is 8.09, the Clear Aperture of the rear surface of the first lens is 7.88, the Clear Aperture of the front surface of the second lens is 7.88, the Clear Aperture of the rear surface of the second lens is 7.36, and the beam The Clear Aperture of the front of the splitter is 4.74, the Clear Aperture of the rear of the beam splitter is 4.43, the Clear Aperture of the aperture is 1.84, the Clear Aperture of the front of the third lens is 1.87, and the Clear Aperture of the rear of the third lens is 2.01, the Clear Aperture of the front surface of the fourth lens is 2.08, the Clear Aperture of the rear surface of the fourth lens is 2.11, the Clear Aperture of the front surface of the fifth lens is 2.11, and the Clear Aperture of the rear surface of the fifth lens is 2.21, and , the Clear Aperture of the front surface of the sixth lens may be 2.22, the Clear Aperture of the rear surface of the sixth lens may be 2.46, the Clear Aperture of the front surface of the IR Filter may be 3.76, and the Clear Aperture of the rear surface of the IR Filter may be 4.05, the The unit of the numerical value is millimeters (mm).

The physical property number of glass constituting the first lens is 755275, the physical property number of glass constituting the second lens is 694533, and the physical property number of glass constituting the beam splitter is 517642, a physical property number of glass constituting the third lens is 620603, a physical property number of glass constituting the fourth lens is 755275, and a glass constituting the fifth lens A physical property number of 620603 may be 620603, a physical property number of glass constituting the sixth lens may be 517642, and a physical property number of glass constituting the IR filter may be 517642.

According to another aspect of the present invention, an optical coherence tomography imaging system includes: a light source unit including a first light source irradiating light for obtaining an optical coherence image; a coupler that divides and transmits the light irradiated from the light source unit into a reference unit and a scan unit, adds the light reflected from the reference unit and the light reflected from the object, and transmits the interference image to the optical coherence tomography image capture unit; a scanning unit that scans the light irradiated from the light source unit to the object, and sends the light reflected from the object back to the coupler; a reference unit for receiving and reflecting the light irradiated from the light source unit to form an interference image by combining the light reflected from the scan unit; an optical coherence tomography image capture unit for capturing an interference image between the light reflected from the object and the light reflected from the reference unit; a surface image capture unit configured to capture a surface image of the object and comprising the lens arrangement of claim 1; And, the tomographic line image of the object captured by the optical coherence tomography image capture unit is collected to implement a tomographic image of the object, and it is provided to the display device 1810, and the surface image capture unit of the object captured by the and a control and image acquisition unit for receiving a surface image and providing it to the display device.

The reference unit may include: a collimator for forming the incident light into parallel light; a focusing lens for focusing the parallel light to a reference mirror; and a reference mirror that reflects the light passing through the focusing lens.

The scan unit may include: a collimator for forming the incident light into parallel light; a MEMS mirror that reflects the light passing through the collimator and scans the image acquisition region of the object; a beam splitter for reflecting the light reflected from the MEMS mirror back to the focusing lens; and a focusing lens for focusing the light reflected from the beam splitter onto an object.

The optical coherence tomography imaging system may further include a MEMS mirror controller configured to drive the MEMS mirror to scan the light onto the image acquisition region of the object.

The MEMS mirror control unit may drive the MEMS mirror in two axes.

The MEMS mirror control unit may further include a function of generating a trigger signal for obtaining an image captured by the optical coherence tomography image capture unit or a trigger signal for obtaining an image captured by the surface image capturing unit.

The control and image acquisition unit may further include a function of controlling the MEMS mirror control unit to control the MEMS mirror driving process.

The beam splitter reflects light over a specific wavelength (hereinafter referred to as a 'reference wavelength') and transmits light less than the reference wavelength, the light of the first light source is light above the reference wavelength, and the surface image capture unit , a second light source for irradiating light less than the reference wavelength to the surface of the object to obtain an image of the surface of the object; and the beam splitter that transmits the light of the second light source reflected from the object to advance to the lens arrangement.

The optical coherence tomography image capture unit may include: a collimator for forming the light from the coupler into parallel light; a grating unit extending the parallel light image from the collimator to a longer length; And, it may include a lens arrangement that passes the light emitted from the grating and transmits it to the focal plane.

According to the present invention, there is an effect of providing a system for simultaneously providing a tomography image and a surface image of an object by combining an optical coherence tomography imaging apparatus and a surface imaging apparatus using separate light sources in one system into one system. .

In addition, in the imaging lens array that transmits the surface image to the image sensor, by arranging a plurality of lenses having a specific curvature and thickness at a specific position, even the light passing through the edge of the lens is used to produce a clear image without distortion of the image. There is an effect of providing an imaging lens arrangement that ensures maximum incident light efficiency while forming an image.

1 is a view showing an optical coherence tomography imaging system including an imaging lens arrangement according to the present invention.
FIG. 2 is a view showing an imaging lens arrangement for imaging a surface of an object in an optical coherence tomography imaging system according to the present invention; FIG.
Fig. 3 is a view showing numerical data constituting the imaging lens arrangement of Fig. 2;
4 is a graph showing the lens performance of the imaging lens arrangement of FIG. 2 ;
5 is a graph showing the MTF performance of the lens arrangement of FIG. 2 ;
FIG. 6 is a graph showing relative illumination of an image passing through the lens arrangement of FIG. 2;
Fig. 7 shows a spot diagram for the lens arrangement of Fig. 2;
8 is a view showing the configuration and condensing state of a lens arrangement for optical coherence tomography imaging in the optical coherence tomography imaging system according to the present invention.
Fig. 9 is a view showing numerical data constituting the lens arrangement of Fig. 8;
10 is a graph showing the lens performance of the lens arrangement of FIG. 8;
11 is a graph showing ray aberration of the lens arrangement of FIG. 8;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all of the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

1 is a diagram illustrating an optical coherence tomography imaging system 1000 including an imaging lens arrangement 200 according to the present invention.

The optical coherence tomography imaging system 1000 includes a light source unit 1100 , a coupler 1200 , a reference unit 1300 , a scan unit 1400 , and an optical coherence tomography image to obtain a tomographic image of the object 40 . It includes a capture unit 1500 and a MEMS mirror control unit 1600 .

In addition, the optical coherence tomography imaging system 1000 further includes a surface image capture unit 1700 to acquire a surface image of the object 40 .

The control and image acquisition unit 1800 implements a tomography image of the object by collecting the tomographic image of the object 40 captured by the optical coherence tomography image capture unit 1500 , and displays the implemented image on the display device 1810 . In addition, the surface image of the object 40 captured by the surface image capture unit 1700 is received and the surface image is also displayed on the display device 1810 .

Furthermore, the control and image acquisition unit 1800 controls the operation of the MEMS mirror control unit 1600 to control the entire process for acquiring an optical coherence tomography image.

Hereinafter, the operation of the optical coherence tomography imaging system 1000 will be described in more detail through the functions of each component.

In the light source unit 1100 , the first light source 1110 generates light having a wavelength of 840 nm. The isolator 1120 serves to block the reflected light from entering the first light source 1110 again after passing through the coupler 1200, thereby passing through the coupler 1200 and returning Light propagates only to the optical coherence tomography image capture unit 1500 .

The light irradiated from the first light source 1110 passes through the coupler 1200 and is divided into a reference unit 1300 and a scan unit 1400 and proceeds.

Light traveling in parallel through the collimator 1310 of the reference unit 1300 passes through the focusing lens 1320 , is reflected by the reference mirror 1330 , and enters the coupler 1200 again.

In addition, light passing through the collimator 1410 of the scan unit 1400 and traveling in parallel is reflected by the MEMS mirror 1420 . The MEMS mirror 1420 does not require two mirrors as one mirror rotates in two axes. That is, a tomography image of one surface can be acquired by scanning one x-axis line of the object 40 through rotation in one axis (x-axis), and rotation in the other one-axis (y-axis) is performed. By scanning the other x-axis lines of the object 40 through the screen, the image obtained thereby enables the acquisition of a 3D tomography image. The beam splitter 1430 reflects the light reflected from the MEMS mirror 1420 again, so that the light is incident on the object 40 through the focusing lens 1440 . If the light of the first light source 1110 is light that can be transmitted up to, for example, 5 mm, when the MEMS mirror 1420 is at a point during the x-axis scan, the light is transmitted to a depth of 5 mm of the object 40, (40) The image from the surface of the corresponding point to a depth of 5 mm is reflected and enters the coupler 1200 again.

In this way, when the light reflected from the reference unit 1300 and the light reflected from the scan unit 1400 are combined in the coupler 1200, the distance between the focusing lens 1320 and the reference mirror 1330 and the focusing lens ( When the distance between 1440 ) and the object 40 is the same, an interference fringe is generated, and the interference fringe enters the optical coherence tomography image capture unit 1500 . As such, the interference image entering the optical coherence tomography image capture unit 1500 passes through the collimator 1520 and becomes parallel, and then is extended to a longer length in the grating unit 1530 and the lens arrangement 100 Passes through, the image is formed on the focal plane (focal plane) (10). The focal plane 10 may be a kind of line scan sensor. As described above, in the image formed on the line scan sensor 10 at a time, when the MEMS mirror 1420 is at a point during the x-axis scan, light is transmitted to a specific depth of the object 40 , and the object 40 ) becomes an image of one line from the surface of the corresponding point to the corresponding depth.

This one-line image is acquired by the control and image acquisition unit 1800, and continuously, according to the x-axis scan of the MEMS mirror 1420, one-line images up to a specific depth at each point on the x-axis are continuously controlled and imaged. It is acquired by the acquisition unit 1800 .

As a result, as a result, the control and image acquisition unit 1800 acquires a tomography image of one surface up to a specific depth with respect to the x-axis line of the object by summing the images of one line up to the corresponding depth and the specific depth of the object 40 . Furthermore, when tomography images of adjacent surfaces are continuously acquired as the MEMS mirror 1420 performs a y-axis scan, a 3D tomography image up to a specific depth of the object 40 may be acquired. Such a tomographic image is displayed through the display device 1810 .

The lens arrangement 100 of the optical coherence tomography image capture unit 1500 will be described later in detail with reference to FIGS. 8 to 11 .

On the other hand, the aforementioned beam splitter 1430 has, for example, a characteristic of reflecting light having a wavelength of 800 nm or more and transmitting light having a wavelength of less than 800 nm. Accordingly, as described above, light of a wavelength of 840 nm emitted from the first light source 1110 is reflected in the direction of the object 40 .

Referring to FIG. 1 , a second light source 50 irradiating light having a wavelength of 400 to 630 nm toward the object 40 is provided on the object 40 . When this light is reflected from the surface of the object 40 and enters the beam splitter 1430, the reflected light, that is, the image of the surface of the object 40 is light with a wavelength of less than 800 nm, so that it passes through the beam splitter 1430 and goes out. After passing through the imaging lens array 200, the image is captured on the focal plane 20, and the captured object 40 surface image is also acquired from the control and image acquisition unit 1800. It is displayed through the display device 1810 .

As described above, the optical coherence tomography imaging system 1000 of the present invention simultaneously acquires a tomographic image and a surface image of the object 40 and shows it to the user, thereby enabling the analysis of the object 40 to be performed more effectively.

The MEMS mirror control unit 1600 also serves to generate a trigger signal for reading the image formed on the apparatus 10 and 20 on which the image is formed, collectively referred to as the 'focal plane (10, 20)' from above.

The lens arrangement 200 of the surface image capture unit 1700 will be described later in detail with reference to FIGS. 2 to 7 .

FIG. 2 is a diagram illustrating an imaging lens arrangement 200 for imaging the surface of an object in an optical coherence tomography imaging system according to the present invention, and FIG. 3 is a diagram showing numerical data constituting the imaging lens arrangement of FIG. 2 . It is a drawing.

In the lens arrangement 200 of FIG. 2, the focal length is 50 mm.

2 and 3, the lens assembly 200 includes a first lens (G1, 210), a second lens (G2, 220), a beam splitter (DM, 230), an aperture (STO, 240), the second 3 lenses G3 and 250 , fourth lenses G4 and 260 , fifth lenses G5 and 270 , sixth lenses G6 and 280 , and an IR Filter 290 are included. Hereinafter, all distance units are millimeters (mm), and notation is omitted.

Assuming that the target object-side surface of each lens described above is the front surface and the focal plane 20 side surface is the rear surface, the first lenses G1 and 210 have the front surfaces G11 and G12 positive. It has a radius of curvature, and the radius of curvature of the front surface G11 of the first lenses G1 and 210 is 12.380, and the radius of curvature of the rear surface G12 is 8.080. The thickness on the central axis 30 of the first lens 210 is 1.00, and the distance on the central axis 30 between the rear surface G12 of the first lens 210 and the front surface G21 of the second lens 220 is 0.52. The physical property number of the glass constituting the first lenses G1 and 210 is 755275.

The first 3 digits of the glass property number indicate the refractive index, and the first 3 digits of '755' in '755275' indicate the refractive index, and the value added with '1.' in front of it is the refractive index. That is, 1.755 is the refractive index. In addition, the last 3 digits of the glass property number are called 'Abbe number' and indicate the degree of dispersion. In '755275', the last 3 digits, '275', indicate the degree of dispersion. In this case, the degree of dispersion is It will be 27.5. The meaning of such a glass property number is equally applied to all lenses below.

'Clear Aperture (CA)' of each lens surface in FIG. 3 refers to the diameter of a region through which a light beam passes in each lens surface of the lens arrangement 200 of FIG. 2 , for example, G11, which is the front surface in FIG. 2 . The CA of the plane refers to the distance between the extreme points 41 and 42 through which the light beam passes. Referring to FIG. 3 , in the lens arrangement 200 of the present invention, the Clear Aperture of the G11 surface, which is the front surface of the first lenses G1 and 210 , is 8.09, and the Clear Aperture of the G12 surface, which is the rear surface, is 7.88.

The second lens (G2, 220) has a positive radius of curvature on the front surface (G21) and a negative radius of curvature on the rear surface (G22), the radius of curvature of the front surface (G21) is 17.290, and the radius of curvature of the rear surface (G22) is - 70.580. The thickness on the central axis 30 of the second lens 220 is 1.52, and the distance on the central axis 30 between the rear surface G22 of the second lens 220 and the front surface DM1 of the beam splitter DM, 230. is 6.87. The physical property number of the glass constituting the second lenses G2 and 220 is 694533. The clear aperture of the front G21 side is 7.88, and the clear aperture of the rear G22 side is 7.36.

The beam splitter (DM, 230) has an infinite radius of curvature as a front surface (DM1) and a rear surface (DM2) are planar. The thickness on the central axis 30 of the beam splitter DM, 230 is 1.26, and the distance on the central axis 30 between the rear surface DM2 of the beam splitter DM, 230 and the stop STO 240 is 6.87. The physical property number of the glass constituting the beam splitter DM 230 is 517642. The clear aperture of the DM1 side, which is the front side, is 4.74, and the clear aperture of the DM2 side, the back side, is 4.43.

The third lens (G3, 250) has a positive radius of curvature on the front surface (G31) and a negative radius of curvature on the rear surface (G22), the radius of curvature of the front surface (G31) is 6.860, and the radius of curvature of the rear surface (G32) is - It is 16.980. The thickness on the central axis 30 of the third lens 250 is 1.09, and the interval on the central axis 30 between the aperture STO 240 and the front surface G31 of the third lens 250 is 0.00, and is at the same position. have. The distance on the central axis 30 between the rear surface G32 of the third lens 250 and the front surfaces G41 of the fourth lenses G4 and 260 is 0.44. The physical property number of the glass constituting the third lenses G3 and 250 is 620603. The Clear Aperture of the G31 surface is 1.87, and the Clear Aperture of the G32 surface is 2.01.

The fourth lens (G4, 260) has a positive radius of curvature on the front surface (G41) and the rear surface (G42), the radius of curvature of the front surface (G41) of the fourth lens (G4, 260) is 15.940, and the fourth lens (G4) , 260) is in contact with the front surface G51 of the fifth lenses G5 and 270 without a spaced interval, and the radius of curvature of the G42 surface is 5.000, the same as the radius of curvature of the G51 surface. The thickness on the central axis 30 of the fourth lenses G2 and 260 is 1.00, and the physical property number of the glass constituting the fourth lenses G4 and 260 is 755275. The Clear Aperture of the G41 surface is 2.08, and the Clear Aperture of the G42 surface is 2.11.

The fifth lens (G5, 270) has a positive radius of curvature on the front surface (G51) and a negative radius of curvature on the rear surface (G52), the radius of curvature of the front surface (G51) is 5.000, and the radius of curvature of the rear surface (G52) is - It is 14.280. The thickness on the central axis 30 of the fifth lens 270 is 1.50, and the distance on the central axis 30 between the rear surface G52 of the fifth lens 270 and the front surface G61 of the sixth lens 280 is 0.78. The physical property number of the glass constituting the fifth lenses G5 and 270 is 620603. The Clear Aperture of the G51 side is 2.11, and the Clear Aperture of the G52 side is 2.21.

The sixth lens (G6, 280) has a negative radius of curvature on the front surface (G61) and a positive radius of curvature on the rear surface (G62), the radius of curvature of the front surface (G61) is -5.000, and the radius of curvature of the rear surface (G62) is It is 7.210. The thickness on the central axis 30 of the sixth lens 280 is 1.23, and the distance on the central axis 30 between the rear surface G62 of the sixth lens 280 and the front surface IRF1 of the IR filter 290 is 3.01. to be. The physical property number of the glass constituting the sixth lens 280 is 517642. The Clear Aperture of the G61 surface is 2.22, and the Clear Aperture of the G62 surface is 2.46.

The front surface (IRF1) and the rear surface (IRF2) of the IR Filter 290 are flat and have an infinite radius of curvature, the thickness on the central axis 30 of the IR Filter 290 is 1.00, and the rear surface of the IR Filter 290 ( The distance on the central axis 30 from the IRF2 to the focal plane 20 is 0.992. The physical property number of the glass constituting the IR Filter 290 is 517642. In the IRF1 side, the Clear Aperture is 3.76, and in the IRF2 side, the Clear Aperture is 4.05.

Hereinafter, with reference to FIGS. 4 to 7 , differences in the results shown by the configuration of the lens arrangement 200 of FIG. 2 as described above will be described.

4 is a graph illustrating lens performance of the imaging lens arrangement 200 of FIG. 2 .

FIG. 4(a) is spherical aberration of the lens arrangement 200, FIG. 4(b) is astigmatism, and FIG. 4(c) is distortion.

The spherical aberration of FIG. 4(a) refers to the vertical distance from the focal plane to the point where the actual focus is formed. In FIG. 4A , the vertical axis is the distance from the center (=0) of the focal plane in the left and right direction, and the horizontal axis is the vertical distance (aberration) from the focal plane to the actual focal point at the corresponding position. As shown in FIG. 4( a ), the spherical aberration of the lens arrangement 200 of the present invention is approximately 0.1 or less, indicating excellent performance.

The astigmatism of FIG. 4(b) refers to an aberration in which a dot-shaped object is formed to hang vertically (in a concentric circle direction) radially from an off-axis. As shown in FIG. 4(b) , the astigmatism of the lens arrangement 200 of the present invention is approximately 0.05 or less, indicating excellent performance.

The distortion aberration of FIG. 4(c) represents the degree to which the screen looks curved in %, and it can be seen that excellent performance is exhibited by showing aberration close to 0% even at the edge of the image.

5 is a graph showing the MTF performance of the lens arrangement 200 of FIG. 2 .

The horizontal axis of FIG. 5 is a defocusing position, where the zero part is the center of the image, and the position away from it in all directions, and the vertical axis is an index indicating the performance of the lens arrangement how clearly the image is focused. Referring to the drawings, it can be seen that the performance of about 73% is shown in the center of the image, and from this, the performance of the imaging lens array 200 for capturing a surface image of the present invention is very excellent.

FIG. 6 is a graph illustrating relative illumination of an image passing through the lens arrangement 200 of FIG. 2 .

Unless a very large lens is used, the relative illuminance will inevitably decrease as it moves away from the center (position 0.00). Although the lens assembly 200 of the present invention uses small lenses, the relative illuminance of the image passing through the lens assembly 200 shows about 86.3% of the relative illuminance even at the farthest 2.25 mm position, which is very excellent overall. performance can be seen.

FIG. 7 is a diagram illustrating a spot diagram of the lens arrangement 200 of FIG. 2 .

When looking at the lens through the object, it is clearly seen through the center of the lens, but the shape of the object becomes disturbed as the lens is viewed obliquely through the lens. 7 illustrates a visible shape of a point-shaped object when viewed through the lens arrangement 200 of the present invention. Referring to FIG. 7 , it can be seen that the lens has very excellent quality by showing very little distortion of the shape, that is, a uniform shape even when looking at an oblique line from left to right or up and down.

8 is a view showing the configuration and condensing state of the lens arrangement 100 for securing maximum incident light efficiency according to the present invention, and FIG. 9 is a view showing numerical data constituting the lens arrangement 100 of FIG. It is a drawing.

In the lens arrangement 100 of FIG. 8, the focal length is 60 mm.

8 and 9 , the lens assembly 100 includes first lenses G1 and 110 , second lenses G2 and 120 , third lenses G3 and 130 , and fourth lenses G4 and 140 . ) and an aperture (STO, 150). Hereinafter, all distance units are millimeters (mm), and notation is omitted.

Assuming that the target object-side surface of each lens described above is the front surface and the focal plane 10 side surface is the rear surface, the first lenses G1 and 110 have positive curvatures of the front surfaces G11 and G12. The radius of curvature of the front surface G11 of the first lenses G1 and 110 is 29.79, and the radius of curvature of the rear surface G12 is 80.49. The thickness on the central axis 30 of the first lens 110 is 5.21, and the distance on the central axis 30 between the rear surface G12 of the first lens 110 and the front surface G21 of the second lens 120 is is 0.2. The physical property number of the glass constituting the first lenses G1 and 110 is 744449.

'Clear Aperture (CA)' of each lens surface in FIG. 9 refers to the diameter of a region through which a light beam passes in each lens surface of the lens arrangement 100 of FIG. 8 , for example, G11, which is the front surface in FIG. The CA of the plane refers to the distance between the extreme points 31 and 32 through which the light beam passes. Referring to FIG. 9 , in the lens arrangement 100 of the present invention, the Clear Aperture of the G11 surface, which is the front surface of the first lenses G1 and 110 , is 31.8, and the Clear Aperture of the G12 surface, which is the rear surface, is 30.0.

The second lenses G2 and 120 have a front surface G21 and a rear surface G22 having a positive radius of curvature, and the front surface G21 has a radius of curvature of 17.08. The rear surface G22 is a portion in contact with the front surface G31 of the third lenses G3 and 130 without a spaced interval, and the radius of curvature of the surface G22 is 125.8, the same as the radius of curvature of the surface G31. The thickness on the central axis 30 of the second lenses G2 and 120 is 7.68, and the physical property number of the glass constituting the second lenses G2 and 120 is 678555. The Clear Aperture of the G21 surface is 24.6, and the Clear Aperture of the G22 surface is 19.9.

The third lens (G3, 130) has a positive radius of curvature on the front surface (G31) and the rear surface (G32), the radius of curvature of the front surface (G31) of the third lens (G3, 130) is 125.8, the curvature of the rear surface (G32) The radius is 10.37, and the radius of curvature of the G31 surface is the same as the radius of curvature of the G22 surface as described above. The thickness on the central axis 30 of the third lenses G3 and 130 is 1.55, and the distance on the central axis 30 from the rear surface G32 of the third lenses G3 and 130 to the stop 150 is 8.01. . The physical property number of the glass constituting the third lenses G3 and 130 is 755275. The Clear Aperture of the G31 side is 19.9, the same as the G22 side, and the Clear Aperture of the G32 side is 14.0.

The distance on the central axis 30 from the stop (STO, 150) to the front surface (G41) of the fourth lens (G4, 140) is 13.95, and the clear aperture of the stop (STO, 150) is 11.3.

The fourth lens (G4, 140) has a negative radius of curvature of the front surface (G41) and the rear surface (G42), the radius of curvature of the front surface (G41) of the fourth lens (G4, 140) is -52.54, the rear surface (G42) The radius of curvature is -22.3. The thickness on the central axis 30 of the fourth lenses G4 and 140 is 4.53, and the central axis 30 from the rear surface G42 of the fourth lenses G4 and 140 to the focal plane 10 . The spacing of the phases is 28.62063. The physical property number of the glass constituting the fourth lenses G4 and 10 is 744449. On the G41 side, the Clear Aperture is 22.0, and on the G42 side, the Clear Aperture is 23.8.

In a lens system, f-number is a value (=f'/D) obtained by dividing the focal length (f') by the diameter (D) through which light passes. Regardless of the type of lens, if the same value is obtained, the same amount of light enters. means When the value of f-number is large, it means that the amount of incoming light is small. Conversely, when the value is small, it means that the amount of incoming light is large.

In the lens arrangement 100 of the present invention configured exactly as described above, f-number = f'/D = 60/31.8. D is the light passage diameter of the G11 surface of the first lenses G1 and 110, which is the first lens surface through which light passes, that is, the Clear Aperture value, and f' is the focal length 60 of the lens arrangement 100.

As described above, the f-number of the lens array 100 of FIG. 8 composed of numerical data as shown in FIG. 9 of the present invention is designed to be a value of 2 or less, using a lens having the maximum diameter that can produce the desired performance. It can be seen that by absorbing light, even the light passing through the edge of the lens is used to form a clear image without distortion of the image, while ensuring maximum incident light efficiency.

10 is a graph showing the lens performance of the lens assembly 100, and FIG. 11 is a graph showing ray aberration of the lens assembly, and is a graph showing the ray aberration calculated with the object distance to infinity.

FIG. 10(a) is spherical aberration of the lens arrangement 100, FIG. 10(b) is astigmatism, and FIG. 10(c) is distortion.

The spherical aberration of FIG. 10( a ) refers to the vertical distance from the focal plane to the point where the actual focal point is formed. In FIG. 10( a ), the vertical axis is the distance from the center (=0) of the focal plane in the left and right direction, and the horizontal axis is the vertical distance (aberration) from the focal plane to the actual focal point at the corresponding position. As shown in FIG. 10( a ), the spherical aberration of the lens arrangement 100 of the present invention is approximately 0.1 or less, indicating excellent performance.

The astigmatism of FIG. 10(b) means an aberration in which a dot-shaped object is formed to hang vertically (concentrically) radially from the off-axis.

The distortion aberration of FIG. 10( c ) is the degree to which the screen looks curved as a percentage, and it can be seen that excellent performance is exhibited by showing aberration of 2.5% or less even at the edge of the image.

10, 20: focal plane
30: lens central axis
40: object
50: second light source
100: lens arrangement
110: first lens
120: second lens
130: third lens
140: fourth lens
150: aperture
200: lens arrangement
210: first lens
220: second lens
230: beam splitter (beam splitter)
240: aperture
250: third lens
260: fourth lens
270: fifth lens
280: sixth lens
290: IR Filter
1000: optical coherence tomography imaging system
1100: light source unit
1110: first light source
1120: isolator (isolator)
1200: coupler (coupler)
1300: reference (reference) unit
1310: collimator
1320: focusing lens
1330: reference mirror (mirror)
1400: scan unit
1410: collimator
1420: MEMS mirror
1430: beam splitter (beam splitter)
1440: focusing lens
1500: optical coherence tomography image capture unit
1510: third light source
1520: collimator
1530: grating part
1600: MEMS mirror control unit
1700: surface image capture unit
1800: control and image acquisition unit
1810: display device

Claims (13)

A lens arrangement for acquiring a surface image of an object, comprising:
A first lens, a second lens, a beam splitter, a third lens, a fourth lens, a fifth lens, a sixth lens, an IR filter, which are sequentially disposed, and an aperture disposed between the beam splitter and the third lens
including,
If the target object side of each lens is referred to as the front surface and the focal plane side surface is referred to as the rear surface,
The front and rear surfaces of the first lens, the front surface of the second lens, the front surface of the third lens, the front surface and the rear surface of the fourth lens, the front surface and the rear surface of the fifth lens and the rear surface of the sixth lens have a positive radius of curvature. formed to have
The rear surface of the second lens, the rear surface of the third lens, the rear surface of the fifth lens, and the front surface of the sixth lens are formed to have a negative radius of curvature,
The front and rear surfaces of the beam splitter, the front and rear surfaces of the IR Filter are formed to have an infinite radius of curvature as a plane,
A lens arrangement for acquiring a surface image of an object. The method according to claim 1,
The first lens is
The thickness on the central axis is 1.00, the radius of curvature of the front is 12.380, the radius of curvature of the rear is 8.080,
The second lens,
The thickness on the central axis is 1.52, the radius of curvature of the front is 17.290, the radius of curvature of the rear is -70.580,
The beam splitter is
The thickness on the central axis is 1.26, the radius of curvature of the front and rear surfaces is infinite,
The third lens,
The thickness on the central axis is 1.09, the radius of curvature of the front is 6.860, the radius of curvature of the rear is -16.980,
The fourth lens,
The thickness on the central axis is 1.00, the radius of curvature of the front is 15.940, the radius of curvature of the rear is 5.000,
The fifth lens,
The thickness on the central axis is 1.50, the radius of curvature of the front is 5.000, the radius of curvature of the rear is -14.280,
The sixth lens,
The thickness on the central axis is 1.23, the radius of curvature of the front is -5.000, the radius of curvature of the rear is 7.210,
The IR Filter,
The thickness on the central axis is 1.00, the radius of curvature of the front and rear surfaces is infinite,
The distance on the central axis between the rear surface of the first lens and the front surface of the second lens is 0.52,
The distance on the central axis between the rear surface of the second lens and the front surface of the beam splitter is 6.87,
the distance on the central axis between the rear face of the beam splitter and the aperture is 6.87;
The distance on the central axis between the diaphragm and the front surface of the third lens is 0.00,
The distance on the central axis between the rear surface of the third lens and the front surface of the fourth lens is 0.44,
The rear surface of the fourth lens and the front surface of the fifth lens are in contact without a separation interval,
The distance on the central axis between the rear surface of the fifth lens and the front surface of the sixth lens is 0.78,
The distance on the central axis between the rear surface of the sixth lens and the front surface of the IR filter is 3.01,
The distance on the central axis between the rear surface of the IR Filter and the focal plane is 0.992,
The unit of the numerical value is millimeters (mm)
A lens arrangement for acquiring a surface image of an object, characterized in that 3. The method according to claim 2,
The Clear Aperture of the front of the first lens is 8.09,
Clear Aperture of the rear of the first lens is 7.88,
The Clear Aperture of the front side of the second lens is 7.88,
The Clear Aperture of the rear side of the second lens is 7.36,
Clear Aperture of the front side of the beam splitter is 4.74,
Clear Aperture of the rear side of the beam splitter is 4.43,
Clear Aperture of the aperture is 1.84,
Clear Aperture of the front of the third lens is 1.87,
Clear Aperture of the rear side of the third lens is 2.01,
Clear Aperture of the front of the fourth lens is 2.08,
Clear Aperture of the rear of the fourth lens is 2.11,
Clear Aperture of the front of the fifth lens is 2.11,
Clear Aperture of the rear of the fifth lens is 2.21,
Clear Aperture of the front of the sixth lens is 2.22,
The Clear Aperture of the rear side of the sixth lens is 2.46,
The Clear Aperture of the front side of the IR Filter is 3.76,
The Clear Aperture of the rear side of the IR Filter is 4.05,
The unit of the numerical value is millimeters (mm)
A lens arrangement for acquiring a surface image of an object, characterized in that 4. The method according to claim 3,
The physical property number of the glass constituting the first lens is 755275,
The physical property number of the glass constituting the second lens is 694533,
The physical property number of the glass constituting the beam splitter is 517642,
The physical property number of the glass constituting the third lens is 620603,
The physical property number of the glass constituting the fourth lens is 755275,
The physical property number of the glass constituting the fifth lens is 620603,
The physical property number of the glass constituting the sixth lens is 517642,
The physical property number of the glass constituting the IR Filter is 517642,
A lens arrangement for acquiring a surface image of an object, characterized in that An optical coherence tomography imaging system comprising:
a light source unit having a first light source irradiating light for obtaining an optical interference image;
a coupler that divides the light irradiated from the light source unit into a reference unit and a scan unit and transmits the light reflected from the reference unit and the light reflected from the object, and transmits the interference image to the optical coherence tomography image capture unit;
a scanning unit that scans the light irradiated from the light source unit to the object, and sends the light reflected from the object back to the coupler;
a reference unit for receiving and reflecting the light irradiated from the light source unit to form an interference image by combining the light reflected from the scan unit;
an optical coherence tomography image capture unit for capturing an interference image between the light reflected from the object and the light reflected from the reference unit;
a surface image capture unit configured to capture a surface image of the object and comprising the lens arrangement of claim 1; and;
The tomographic line image of the object captured by the optical coherence tomography image capture unit is collected to realize a tomographic image of the object, and it is provided to the display device 1810, and the surface image of the object captured by the surface image capture unit Control and image acquisition unit for receiving and providing to the display device
Optical coherence tomography imaging system comprising a. 6. The method of claim 5,
The reference unit,
a collimator for forming the incident light into parallel light;
a focusing lens for focusing the parallel light to a reference mirror; and
A reference mirror that reflects light passing through the focusing lens
Optical coherence tomography imaging system comprising a. 7. The method of claim 6,
The scan unit,
a collimator for forming the incident light into parallel light;
a MEMS mirror that reflects the light passing through the collimator and scans the image acquisition region of the object;
a beam splitter for reflecting the light reflected from the MEMS mirror back to the focusing lens; and;
A focusing lens that focuses the light reflected from the beam splitter onto an object
Optical coherence tomography imaging system comprising a. 8. The method of claim 7,
A MEMS mirror controller that drives the MEMS mirror to scan the light onto the image acquisition region of the object
Optical coherence tomography imaging system, characterized in that it further comprises. 9. The method of claim 8,
The MEMS mirror control unit,
driving the MEMS mirror in two axes
Optical coherence tomography imaging system, characterized in that. 9. The method of claim 8,
The MEMS mirror control unit,
A function of generating a trigger signal for obtaining an image captured by the optical coherence tomography image capture unit or a trigger signal for obtaining an image captured by the surface image capturing unit
Optical coherence tomography imaging system, characterized in that it further comprises. 9. The method of claim 8,
The control and image acquisition unit,
A function of controlling the MEMS mirror control unit to control the MEMS mirror driving process
Optical coherence tomography imaging system, characterized in that it further comprises. 8. The method of claim 7,
The beam splitter is
It reflects light above a specific wavelength (hereinafter referred to as 'reference wavelength') and transmits light below the reference wavelength,
The light of the first light source is the light of the reference wavelength or more,
The surface image capture unit,
a second light source irradiating light less than the reference wavelength to the surface of the object to obtain an image of the surface of the object; and
The beam splitter that transmits the light of the second light source reflected from the object to advance to the lens arrangement
Optical coherence tomography imaging system, characterized in that it further comprises. 6. The method of claim 5,
The optical coherence tomography image capture unit,
a collimator for forming the light from the coupler into parallel light;
a grating unit extending the parallel light image from the collimator to a longer length; and;
A lens arrangement that passes the light emitted from the grating and transmits it to the focal plane
Optical coherence tomography imaging system comprising a.

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