KR100702946B1 - Fiducial lens assembly for vision camera - Google Patents

Abstract

Disclosed is a special lens assembly for a vision camera that recognizes a fiducial mark, which is a reference point of a printed circuit board (PCB) in a chip mount, and checks the state of parts to set all reference points of the equipment.

The disclosed dual lens assembly for a vision camera includes a barrel; A first lens group provided on the object side in the barrel and having a positive refractive power to focus an image on a subject; A second lens group provided on the image side with respect to the first lens group in the barrel and having a positive refractive power; An aperture disposed on an optical path between the first lens group and the second lens group to adjust an amount of light; And an inner lighting means installed in the barrel and illuminating toward the object, wherein the inner lighting means is installed around a focal length of the first lens group.

Description

[Fiducial lens assembly for vision camera}

1 is a cross-sectional view schematically showing a dual lens assembly for a vision camera according to an embodiment of the present invention,

2 is a view showing the optical arrangement of the optical lens optical lens optical system according to an embodiment of the present invention,

3 is a cross-sectional view schematically showing a special lens assembly for a vision camera according to another embodiment of the present invention;

4 is a view showing an optical arrangement of the optical lens optical lens optical system according to another embodiment of the present invention.

<Description of reference numerals for main parts of the drawings>

Ⅰ ... 1st lens group Ⅱ ... 2nd lens group

1 ... Aperture 30 ... Tube

40 Internal lighting means 41 Light source

50.External lighting

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vision lens assembly for vision cameras that recognizes a fiducial mark, which is a reference point of a PCB in a chip mount, and checks the state of parts to set all reference points of equipment.

In general, a conventional lens uses a C mount lens and a CS mount lens used in a surveillance camera. Such a lens has a large distortion aberration, which is not suitable for precision measurement, and thus, the reference point of the chip mount cannot be found, and the fiducial mark is not recognized properly, resulting in a significant reduction in the mounting accuracy of the chip mount. In addition, in the lens design process, the C mount lens and the CS mount lens are based on infinity. Therefore, focusing is difficult for mounting at finite distances used in equipment such as chip mounts. Therefore, it is necessary to reinforce the mount behind the lens, in which case the performance of the lens inherently deteriorates. In addition, the conventional optical system, which is not a telecentric optical system, is recognized as an unsuitable lens for measurement because there is a change in magnification according to a change in height of an object plane.

The present invention has been made in view of the above-described points, and corrects chromatic aberration and distortion aberration, satisfies the distance between objects required by the equipment, minimizes the change in magnification according to the height change of the object and improves the resolution An object of the present invention is to provide a dual lens assembly for a vision camera.

The objective lens assembly for a vision camera of the present invention for achieving the above object, the barrel; A first lens group provided on the object side in the barrel and having a positive refractive power to focus an image on a subject; A second lens group installed in the image barrel with respect to the first lens group and having positive refractive power; An aperture disposed on an optical path between the first lens group and the second lens group to adjust an amount of light; An internal illumination means installed in the barrel and illuminating toward an object, wherein the first lens group has a positive refractive power, the first lens group being sequentially disposed from an object side. A second meniscus having a biconvex lens and a first meniscus lens having a negative refractive power, wherein the second lens group is disposed sequentially from the first lens group; And a second biconvex lens having positive refractive power.

In addition, the internal lighting means is installed around the focal length of the first lens group.

In addition, it is characterized in that it is provided on the outside of the barrel further provided with external lighting for illuminating toward the object.

Hereinafter, a dual lens assembly for a vision camera according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 and 3, a vision lens assembly for a vision camera according to an embodiment of the present invention is installed in the barrel 30, the first and second to be installed in the barrel to correct chromatic aberration and distortion aberration A physical lens optical system 100 composed of lens groups (I) and (II), and an internal lighting means 40 installed in the barrel and illuminating toward an object.

The barrel 30 includes a first barrel 31 surrounding the first lens group and a second barrel 32 surrounding the second lens group. The first barrel is fixed to the second barrel via a fixing screw 33. A first fixing member 34 for fixing the first lens group to the first barrel is coupled to the outer circumferential surface of the first lens group. In addition, a second fixing member 35 which fixes the second lens group to the second barrel is coupled to the outer circumferential surface of the second lens group.

The physical lens optical system 100 is a telecentric optical system, the first lens group I having positive refractive power to focus an image on a subject, an aperture 1 for adjusting the amount of light, and a positive refractive power. It includes a second lens group (II) having a.

The first lens group I includes a first biconvex lens 11 having positive refractive power and a first meniscus lens 12 having negative refractive power, which are sequentially disposed from an object side. It is composed.

The second lens group II includes a second meniscus lens 21 having a negative refractive power and a second biconvex lens 22 having a positive refractive power, which are sequentially arranged from the first lens group. do.

Here, the combined focal length of the first lens group I is f1, the combined focal length of the second lens group II is f2, and the distance between the object plane and the light incident surface of the first lens group on the optical axis is object distance. In the above, it is preferable that the relationship between f1, f2 and the object distance of the objective lens optical system of the present invention satisfies Equation 1 below.

0.03 ≤ (f1 / f2) / object distance ≤ 0.04

The physical lens optical system satisfying Equation 1 corrects distortion aberration, satisfies the distance between objects required by the equipment, minimizes the change of magnification according to the height change of the object, and improves the resolution.

In addition, chromatic aberration correction of the lens is performed by using a material having a different dispersion between the lens having positive refractive power and the lens having negative refractive power.

Here, the Abbe number of the first biconvex lens 11 having positive refractive power is V1, and the Abbe number of the first meniscus lens 12 having negative refractive power is V2, and the second meniscus lens having negative refractive power ( When the Abbe number of 21) is V3 and the Abbe number of the second biconvex lens 22 having positive refractive power is V4, in order to remove chromatic aberration of the lens, the objective lens optical system of V1 to V4 is as follows. It is preferable to satisfy the expressions (2) and (3).

45 〈V1 〈65

35 〈V2 〈45

45 〈V3 〈65

35 〈V4 〈45

 Table 1 shows lens data according to an embodiment of the physical lens optical system configured as described above.

Radius of curvature Thickness / spacing Lens material First lens group R1 = 0.08138 d1 = 0.015682 BAF 10_HOYA R2 = -0.04424 d2 = 0.003337 FD4_HOYA R3 = -0.20789 d3 = 0.086750 iris         ∞ d4 = 0.061602 2nd lens group R5 = 0.09499 d5 = 0.003337 FD4_HOYA R6 = 0.02552 d6 = 0.012789 BAF 10_HOYA R7 = -0.06413 d7 = -0.583072

Here, when the effective focal length EFL of the optical system 100 is f, Ri (i = 1, 2, 3, 5, 6, 7) is divided by f by the radius of curvature of the light exit surface of each lens. The value is normalized, and dj (j = 1, 2, 5, 6) is the value normalized by dividing the thickness of each lens on the optical axis by f. d3 is a value obtained by dividing the distance between the light exit surface and the aperture of the first lens group on the optical axis by f, and d4 is the distance between the aperture and the light incident surface of the second lens group on the optical axis by f It is the standardized value by sharing. d7 is a value obtained by dividing the distance between the light exit surface and the image surface of the second lens group on the optical axis by f.

Table 2 shows data of the physical lens optical system according to the embodiment of Table 1 above.

Object distance [mm] BFL / EFL F / NUMBER Magnification ANG [。] 45 -0.6 14.6 0.02 0.96

Here, the object distance is the distance between the object surface and the light incident surface of the first lens group on the optical axis, and BFL / EFL refers to a value obtained by dividing the rear focus distance BFL by the effective focus distance. F / NUMBER is a numerical value for the size of the aperture, expressed as the ratio of the effective focal length to the effective diameter. Magnification is expressed as the ratio of the size of an object to the size of an image. ANG is the angle between the chief ray and the optical axis.

The internal lighting means 40 is provided around the focal length of the first lens group I so as not to be in a position that obstructs the path of light passing through the lens group from the object side.

The internal lighting means 40 is a light source 41 for illuminating parallel to the optical axis toward the object is installed in the barrel 30, the first PCB 42 for operating the light source 41 is coupled to the light source Is installed. An insulating member 43 is interposed between the first PCB 42 and the second barrel 32 to prevent energization that may occur by connecting electric wires for power connection of the light source 41. A diffusion member 44 is installed facing the light source to diffuse light from the light source.

In addition, the exterior of the barrel 30 is preferably provided with an external illumination (50) to be inclined toward the object. In addition, a second PCB 52 coupled to the external light 50 to operate the external light and an external fixing member 53 for fixing the external light and the second PCB to the first barrel are installed.

In order to correspond to various surface structures of the object is provided with an internal illumination means 40 for illuminating parallel to the optical axis, and an external illumination 50 for illuminating obliquely with the optical axis.

3 and 4, a vision lens assembly for a vision camera according to another exemplary embodiment of the present invention includes a barrel 30 and a first and second parts installed in the barrel to correct chromatic aberration and distortion aberration. A physical lens optical system 200 composed of lens groups (I) and (II), and an internal lighting means 40 provided in the barrel and illuminating toward an object.

The barrel 30 includes a first barrel 31 surrounding the first lens group and a second barrel 32 surrounding the second lens group. Here, the same reference numerals as in the above-described drawings refer to the same member having the same function, and are substantially the same as described above, and thus detailed description thereof will be omitted.

The physical lens optical system 200 is a telecentric optical system, which is arranged sequentially from the object side and has a first refractive lens group I having positive refractive power to focus an image on a subject, and adjusts the amount of light. An aperture 1 and a second lens group II having positive refractive power are included.

 The physical lens optical system 200 according to the present exemplary embodiment includes a second meniscus lens 21 and a second biconvex lens 22 of the second lens group II through a third fixing member 36. It is separated from the physical lens optical system 100 according to an embodiment in that it is separated.

Table 3 shows lens data according to an embodiment of a physical lens optical system configured as described above.

Radius of curvature Thickness / spacing Lens material First lens group R1 = 0.04603 d1 = 0.009587 BSC7_HOYA R2 = 0.02428 d2 = 0.001989 F2_HOYA R3 = -0.06605 d3 = 0.051715 iris         ∞ d4 = 0.027287 2nd lens group R5 = 0.02250 d5 = 0.002287 FD4_HOYA R6 = 0.01378 d = 0.008376 R7 = 0.02919 d7 = 0.008155 FC5_HOYA R8 = -0.02250 d8 = -0.598600

Here, when the effective focal length EFL of the optical system 200 is f, Ri (i = 1, 2, 3, 5, 6, 7, 8) is the radius of curvature of the light exit surface of each lens as f. It is the value normalized by dividing, and dj (j = 1, 2, 5, 7) is the value normalized by dividing the thickness of each lens on the optical axis by f. d3 is a value obtained by dividing the distance between the light exit surface and the aperture of the first lens group on the optical axis by f. d4 is a value obtained by dividing the interval between the aperture on the optical axis and the light incident surface of the second lens group by f. d is a value obtained by dividing the distance between the second meniscus lens and the second biconvex lens on the optical axis by f. d8 is a value obtained by dividing the distance between the light exit surface and the image surface of the second lens group on the optical axis by f.

In the physical lens optical system 200 according to the present embodiment, the d satisfies Equation 4 below.

0.0058632 〈d 〈0.0108888

Table 4 shows data of the physical lens optical system 200 according to the present embodiment of Table 3 above.

Object distance [mm] BFL / EFL F / NUMBER Magnification ANG [。] 49.72 -0.61 15.8 0.02 0.96

Here, it can be seen that there is no change in magnification due to the change of the object distance.

Therefore, the physical lens optical system 200 that satisfies Equation 4 may further improve distortion aberration and resolution.

As described above, the objective lens assembly for a vision camera according to the present invention uses a telecentric optical system to correct chromatic aberration and distortion aberration of a lens, satisfy a distance between objects required by equipment, and change the height of an object. There is an advantage that the change in magnification can be minimized. In addition, the use of telecentric optical system has the advantage that the coaxial light can be placed inside to create an image with a constant lighting effect for various physical marks.

In addition, the dual lens assembly for a vision camera according to another embodiment of the present invention further corrects distortion and improves resolution by separating the second meniscus lens and the second biconvex lens of the second lens group. There is an advantage that it can be improved.

As described above, the objective lens assembly for a vision camera of the present invention has been described using an example of a vision lens for a vision camera as an example, but the present invention is not limited to the above-described embodiment, and various modifications are made within the scope of the claims. Yes it is possible.

Claims (9)

Neck pain; A first lens group provided on the object side in the barrel and having a positive refractive power to focus an image on a subject; A second lens group installed in the image barrel with respect to the first lens group and having positive refractive power; An aperture disposed on an optical path between the first lens group and the second lens group to adjust an amount of light; And an internal illumination means installed in the barrel to illuminate toward an object. The method of claim 1, The first lens group includes a first biconvex lens having positive refractive power and a first meniscus lens having negative refractive power, which are sequentially arranged from an object side, The second lens group includes a second meniscus lens having a negative refractive power, and a second biconvex lens having a positive refractive power, sequentially arranged from the first lens group. Dual lens assembly. The method of claim 2, When f is the effective focal length of the fiddle assembly for the vision camera and f is a value obtained by dividing the distance between the second meniscus lens and the second biconvex lens by f, d is Particular lens assembly for a vision camera, characterized in that satisfactory. Equation 0.0058632 〈d 〈0.0108888 The method according to any one of claims 1 to 3, When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, the relationship between f1, f2 and the object distance satisfies the following equation. Lens assembly. Equation 0.03 ≤ (f1 / f2) / object distance ≤ 0.04 The method according to claim 2 or 3, When the Abbe number of the first biconvex lens is V1 and the Abbe number of the first meniscus lens is V2, V1 and V2 satisfy the following equation. . Equation 45 〈V1 〈65 35 〈V2 〈45 The method according to claim 2 or 3, When the Abbe number of the second meniscus lens is V3 and the Abbe number of the second biconvex lens is V4, V3 and V4 satisfy the following equation. . Equation 45 〈V3 〈65 35 〈V4 〈45 The method of claim 1, wherein the internal lighting means, A focal lens assembly for a vision camera, characterized in that installed around the focal length of the first lens group. The method of claim 1 or 7, wherein the internal lighting means, A light source installed inside the barrel to illuminate an object; An insulating member interposed between the light source and the barrel to prevent energization that may occur when the power source is connected to the light source; And a diffusion member for diffusing light emitted from the light source. The method of claim 1, The external lens is installed on the outside of the barrel, the optical lens assembly for the vision camera, characterized in that it further comprises an illumination.

Images