CN114324365B - Curved surface detection device - Google Patents
Curved surface detection device Download PDFInfo
- Publication number
- CN114324365B CN114324365B CN202210022328.8A CN202210022328A CN114324365B CN 114324365 B CN114324365 B CN 114324365B CN 202210022328 A CN202210022328 A CN 202210022328A CN 114324365 B CN114324365 B CN 114324365B
- Authority
- CN
- China
- Prior art keywords
- ellipsoidal mirror
- light
- long axis
- focus
- detected
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
The embodiment of the invention discloses a curved surface detection device, which comprises a light source, an ellipsoidal mirror and an imaging system, wherein the ellipsoidal mirror is designed to be of a hollow structure, the surface of the ellipsoidal mirror comprises a slot, the light emitted from one focus is reflected by the inner surface of the ellipsoidal bowl and then converged at the other focus by utilizing the characteristic that an ellipsoidal reflecting bowl is used for reflecting the light emitted from the other focus, the light source is arranged at a first focus of a long axis of the ellipsoidal mirror, an object to be detected passes through an opening area of the slot and is arranged at a second focus of the long axis, the detection light emitted by the light source is reflected by an inner reflecting surface of the ellipsoidal mirror and then reaches a detection area of the object to be detected to be reflected to form reflected light, the reflected light is emitted by the slot, the imaging system receives the reflected light and generates an image formed on the surface of the detection area, and further surface defects are identified.
Description
Technical Field
The embodiment of the invention relates to the technical field of detection, in particular to a curved surface detection device.
Background
With the deep and popular industrial automation and intellectualization, the use of automatic optical inspection equipment (Auto Optical Inspection, AOI) to replace traditional manual visual inspection has become a trend in technology development. AOI equipment is widely used in the fields of automobiles, medicines, traffic, semiconductors and the like by virtue of the rapid and accurate defect identification positioning capability.
Currently, existing AOI equipment typically includes optical imaging systems, stages, material transport systems, and the like. Wherein the optical imaging system comprises an illumination unit, an imaging objective, a detector, etc. The illumination unit is responsible for providing the required radiant light, the objective is used for collecting the surface light signal that awaits measuring, and the detector is responsible for converting light into digital signal. The schematic structure is shown in fig. 1.
In order to adapt to different process requirements, an illumination system of the current AOI detection device is generally divided into a bright field illumination and a dark field illumination, taking bare silicon wafer detection as an example, the bright field illumination is usually coaxial illumination, if a silicon wafer has no defect, most light can return to an objective lens in an original way, be imaged on a CCD, if the silicon wafer has the defect, the incident light can be absorbed or scattered, and only a small part of light can enter the objective lens to be imaged, so that the defect seen by people is dark under the bright field illumination.
The conventional AOI inspection apparatus (as shown in fig. 1) can better acquire an image of a flat surface, so that corresponding defects can be identified through image processing, but for some uneven surfaces, particularly surfaces with larger radians, such as round arc surfaces at edges of materials such as silicon wafers and glass, because the normal line of the surface to be inspected is not always parallel to the optical axis of the objective lens, the incident light and the reflected light of the surface to be inspected are not always symmetrical about the optical axis of the objective lens, even if the surface to be inspected has no defect, the reflected light can not return to the objective lens in the original path, and as shown in fig. 2, field of view is lost or false detection can occur.
Disclosure of Invention
The embodiment of the invention provides a curved surface detection device, which utilizes the scattered illumination of an ellipsoidal reflector to fully utilize the energy of a light source and improve the detection accuracy while meeting the detection requirement of the edge of a silicon wafer.
In a first aspect, an embodiment of the present invention provides a curved surface detection apparatus, including a light source, an ellipsoidal mirror, and an imaging system;
the ellipsoidal mirror is of a hollow structure, the surface of the ellipsoidal mirror comprises a slot, and the slot comprises a first arc edge and a second arc edge; the ellipsoidal mirror further comprises a central plane where the long axis is located, and the central plane is parallel to a plane where the first arc edge is located and a plane where the second arc edge is located respectively;
the light source is positioned on the first focal point of the long shaft and is used for emitting detection light; the object to be detected passes through the opening area of the slot and is positioned on the second focus of the long shaft, and the detection area of the object to be detected is at least partially in a curved surface; the detection light reaches the detection area of the object to be detected after being reflected by the internal reflection surface of the ellipsoidal mirror, and is reflected to form reflected light which is emitted through the slot;
the imaging system is positioned on the propagation path of the reflected light and is used for collecting the reflected light and imaging the detection area of the object to be detected according to the reflected light.
Optionally, along the long axis direction of the ellipsoidal mirror, the maximum included angle between the connecting line of the second focus and any point on the first arc edge and the long axis direction and the maximum included angle between the connecting line of the second focus and any point on the second arc edge and the long axis direction are all gamma, gamma is less than or equal to 2α, and 0 ° < α is less than 90 °;
along the direction perpendicular to the plane where the first arc edge is located, the width of the slot is 2h, and the following conditions are satisfied:
wherein alpha is the minimum included angle between the tangential plane of the detection area of the object to be detected and the long axis direction, a is half of the long axis length of the ellipsoidal mirror, b is half of the short axis length of the ellipsoidal mirror, c is half of the distance between the first focus and the second focus of the ellipsoidal mirror long axis, and h is half of the width of the slot.
Optionally, the imaging system includes an objective lens, an optical axis of the objective lens is parallel to a plane where the first arc edge is located, and an included angle between the optical axis of the objective lens and the long axis direction is beta, and beta is more than or equal to 10 degrees and less than or equal to 30 degrees.
Optionally, along the long axis direction, the length of the slot is L, which satisfies:
optionally, the imaging system further comprises a tube mirror and a CCD camera.
Optionally, the light source comprises a point light source,
the internal reflection surface of the ellipsoidal mirror comprises scattering particles, and the scattering particles are used for scattering the detection light reaching the internal reflection surface of the ellipsoidal mirror to form a scattered light beam;
the scattering angle of the scattered light beam relative to the detected light is theta 1 The method comprises the following steps:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
Optionally, the scattering angle θ 1 The following is also satisfied:
optionally, the light source comprises a surface light source;
the diameter of the light source of the surface light source is D, and the following conditions are satisfied:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
Optionally, the internal reflecting surface of the ellipsoidal mirror comprises a specular mirror.
Optionally, the light source comprises a bright field light source.
The embodiment of the invention discloses a curved surface detection device, which comprises a light source, an ellipsoidal mirror and an imaging system, wherein the ellipsoidal mirror is designed to be of a hollow structure, the surface of the ellipsoidal mirror comprises a slot, the light emitted from one focus is reflected by the inner surface of the ellipsoidal bowl and then converged at the other focus by utilizing the characteristic that an ellipsoidal reflecting bowl is used for reflecting the light emitted from the inner surface of the ellipsoidal bowl, the light source is arranged at a first focus of a long axis of the ellipsoidal mirror, an object to be detected passes through an opening area of the slot and is arranged at a second focus of the long axis, the detection light emitted by the light source is reflected by an inner reflecting surface of the ellipsoidal mirror and then reaches a detection area of the object to be detected to be reflected to form reflected light which is emitted by the slot, and the imaging system 3 receives the reflected light and generates an image formed on the surface of the detection area, so that surface defects are identified.
Drawings
FIG. 1 is a schematic diagram of a prior art bright field illumination and imaging configuration of a conventional AOI detection device;
FIG. 2 is a schematic diagram of a conventional AOI device for detecting arc surface in the prior art;
fig. 3 is a schematic XY plane structure diagram of a curved surface detecting device according to an embodiment of the present invention;
fig. 4 is a schematic perspective view of an ellipsoidal mirror according to an embodiment of the present invention;
fig. 5 is a schematic view of an XZ plane structure of a curved surface detecting device according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an edge detection light of an object to be detected according to an embodiment of the present invention;
FIG. 7 is a schematic diagram illustrating the angle requirement of incident light at the edge of an object to be measured according to an embodiment of the present invention;
FIG. 8 is a schematic cross-sectional view of an ellipsoidal mirror according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of the condition to be satisfied by the slot length L of an ellipsoidal mirror according to an embodiment of the present invention;
FIG. 10 shows an internal reflection surface scattering angle θ of an ellipsoidal mirror according to an embodiment of the present invention 1 Schematic of (2);
fig. 11 is a schematic view of a surface light source according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 3 is a schematic structural diagram of a curved surface detecting device according to an embodiment of the present invention; fig. 4 is a schematic perspective view of an ellipsoidal mirror according to an embodiment of the present invention; fig. 5 is a schematic cross-sectional view of an ellipsoidal mirror according to an embodiment of the present invention. The curved surface detection device provided by the embodiment of the invention can be used for positioning arc surface images on edges of materials such as silicon chips, glass and the like, identifying edge arc surface defects and the like. Referring to fig. 3 to 5, the curved surface detection device comprises a light source 1, an ellipsoidal mirror 2 and an imaging system 3; the ellipsoidal mirror 2 is of a hollow structure and comprises a slot 20 on the surface, wherein the slot 20 comprises a first arc edge 21 and a second arc edge 22; the ellipsoidal mirror 2 further comprises a central plane where the long axis is located, and the plane where the first arc edge 21 is located and the plane where the second arc edge 22 is located are parallel to the central plane; the light source 1 is positioned on the first focal point F1 of the long axis and is used for emitting detection light; the object 4 to be measured passes through the opening area of the slot 20 and is positioned on the second focal point F2 of the long axis, and the detection area of the object 4 to be measured is at least partially in a curved surface; the detection light reaches the detection area of the object to be detected 4 after being reflected by the internal reflection surface of the ellipsoidal mirror 1, and is reflected to form reflected light which is emitted through the slot 20; the imaging system 3 is located on the propagation path of the reflected light, and is used for collecting the reflected light and imaging the detection area of the object 4 to be detected according to the reflected light.
As shown in fig. 3 to 5, the curved surface detection device light source 1, the ellipsoidal mirror 2 and the imaging system 3 according to the embodiment of the present invention are illustrated, and the ellipsoidal mirror 2 may also be referred to as an ellipsoidal reflecting bowl, and the ellipsoidal mirror 2 is of a hollow structure. The ellipsoidal mirror 2 comprises a long axis, a plane where the long axis of the ellipsoidal mirror 2 is located is arbitrarily selected, the plane is taken as a reference plane, a first arc edge 21 is formed by slotting the surface of the ellipsoidal mirror 2 in the upper area of the reference plane, a second arc edge 22 is formed by slotting the surface of the ellipsoidal mirror 2 in the lower area of the reference plane, and the plane where the first arc edge 21 and the plane where the second arc edge 22 are located are both parallel to the reference plane, so that a slot 20 is formed on the surface of the ellipsoidal mirror 2. A detection area of the object 4 to be measured is placed from the opening area of the slot 20, and the detection area includes an arc-shaped curved surface. The slot 20 is to ensure that the object to be measured (silicon wafer) can be inserted into the ellipsoidal mirror 2, and that the reflected light at the edge of the object to be measured (silicon wafer) can exit from the ellipsoidal mirror 2 into the imaging system 3,
by utilizing the characteristic that light emitted from one focus of the ellipsoidal reflector is converged at the other focus after being reflected by the inner surface of the ellipsoidal reflector, the embodiment of the invention places the light source 1 at the first focus F1 of the long axis for emitting detection light, places the edge vertex of the detection area of the object 4 to be detected at the second focus F2 of the long axis through the slot 20, for example places the edge cambered surface of the wafer at the second focus F2 of the long axis. According to the tangent normal theorem of an ellipse, light rays emitted from the F1 and reflected by the ellipsoid must pass through the F2, and as shown in FIG. 5, light emitted from the center point of the light source must pass through the edge vertex of the silicon wafer by reflection of the ellipsoidal mirror. The light beam emitted from the first focus F1 can reach the object to be detected 4 at the second focus F2 after being reflected by the inner surface of the ellipsoidal mirror 2, and the second focus F2 can obtain incident light with different angles, so as to realize bright field illumination of the surface of the detection area. The detection light is reflected by the detection area to form reflected light, and the reflected light exits through the slot 20, and the imaging system 3 receives the reflected light L3 and generates an image formed on the surface of the detection area. The detected light L3 reflected by the ellipsoidal mirror 2 has concentrated energy, the energy utilization rate of the light source is high and can reach more than 90%, the imaging system 3 can image the object to be detected conveniently, and the surface defect of the object to be detected can be observed conveniently.
In summary, the curved surface detection device provided by the embodiment of the invention comprises a light source, an ellipsoidal mirror and an imaging system, wherein the ellipsoidal mirror is designed to be of a hollow structure, the surface of the ellipsoidal mirror comprises a slot, the light emitted from one focus is reflected by the inner surface of the ellipsoidal bowl and then converged at the other focus by utilizing the characteristic that the ellipsoidal reflecting bowl is used for reflecting the light emitted from the other focus, the light source is arranged on the first focus of the long axis of the ellipsoidal mirror, the object to be detected passes through the opening area of the slot and is arranged on the second focus of the long axis, the detection light emitted by the light source is reflected by the inner reflecting surface of the ellipsoidal mirror and then reaches the detection area of the object to be detected to be reflected to form reflected light, the reflected light is emitted by the slot, and the imaging system 3 receives the reflected light and generates an image formed on the surface of the detection area, so that the surface defect is identified.
FIG. 6 is a schematic diagram of an edge detection light of an object to be detected according to an embodiment of the present invention; FIG. 7 is a schematic diagram illustrating the angle requirement of incident light at the edge of an object to be measured according to an embodiment of the present invention; fig. 8 is a schematic cross-sectional view of an ellipsoidal mirror according to an embodiment of the present invention. Referring to fig. 3-8, optionally, along the long axis direction (as shown in the X direction in the figure) of the ellipsoidal mirror 2, the maximum included angle between the connecting line of the second focus F2 and any point on the first arc edge 21 and the long axis direction and the maximum included angle between the connecting line of the second focus F2 and any point on the second arc edge 22 and the long axis direction are all γ, γ is less than or equal to 2α, and 0 ° < α < 90 °; the width of the slot 20 along the direction perpendicular to the plane of the first arc edge 21 is 2h, satisfying:
wherein alpha is the minimum included angle between the tangential plane of the detection area of the object to be detected and the long axis direction, a is half of the length of the long axis of the ellipsoidal mirror, b is half of the length of the short axis of the ellipsoidal mirror, c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror, and h is half of the width of the slot.
Specifically, as shown in connection with fig. 3-8. Because the edge of the detection area of the object 4 to be detected is at least partially in an arc surface, for example, the edge of a silicon wafer is detected, and the edge of the silicon wafer is in an arc surface with a larger radian. As shown in fig. 6, incident light at various angles is irradiated on the arc surface, specular reflection occurs, and imaging is performed after being incident on the imaging system 3 at 0 °. If the included angle α between the tangent line of the edge of the silicon wafer and the long axis direction (X direction in the figure, or horizontal line as well) is usually 0-90 °, the bright field illumination needs to provide incident angle light rays above- (180 ° -2α) to the silicon wafer, and as shown in fig. 7, the light source 1 may optionally include a bright field light source. For example, when the light source is a light emitting device with 360 degrees, the LED filament and the like emit light, under the condition that the ellipsoidal mirror 2 is complete, the incident light received at the vertex of the edge of the silicon wafer is reflected by the ellipsoidal surface of the inner surface of the whole ellipsoidal mirror 2, and the incident light is in the opposite direction of 360 degrees, and the requirements of incident angle light above- (180-2α) are met at the vertex area of the edge of the silicon wafer. Since the ellipsoidal mirror 2 has a slot, a part of the incident light received at the vertex of the edge of the silicon wafer is missing, the width 2h of the slot 20 can be controlled, so that the included angle gamma between F2 and the first arc edge 21 (shown as the point M in fig. 8) of the ellipsoidal mirror 2 and the long axis direction (shown as the direction X in the figure, or can be said as the horizontal line), and the included angle gamma between F2 and the second arc edge 22 (shown as the point N in fig. 8) of the ellipsoidal mirror 2 and the long axis direction (shown as the direction X in the figure, or can be said as the horizontal line) can be controlled, and the requirement gamma is less than or equal to 2α, as shown in fig. 8, and at this time, the incident light of- (180 ° -2α) can be received at the vertex of the edge of the silicon wafer for bright field illumination.
Further, in the XY plane of the ellipsoidal mirror, the elliptic equation satisfied in combination with the ellipsoidal mirror 2 is
a is half of the length of the major axis of the ellipsoidal mirror, b is half of the length of the minor axis of the ellipsoidal mirror, and c is half of the distance between the first focus F1 and the second focus F2 of the major axis of the ellipsoidal mirror. Wherein in the XY plane, F2 has a coordinate of (c, 0), c 2 ＝a 2 -b 2 M point coordinates are
Half h of the width of the slot 20 should satisfy the following formula:
after the major axis and the minor axis of the ellipsoidal mirror 2 and the included angle α between the object 4 to be measured and the major axis direction (X direction in the figure, or horizontal line) are determined, the width 2h of the slot 20 is set, so that the vertex of the edge of the silicon wafer (object to be measured) can receive the incident light of- (180 ° -2α), so that the object to be measured obtains the incident light of different angles, and the requirement of the bright field illumination of the edge is satisfied.
Fig. 9 is a schematic diagram of a slot length L arrangement of an ellipsoidal mirror according to an embodiment of the present invention. As shown in connection with fig. 3-9, the imaging system 3 optionally comprises an objective lens, the optical axis L of which 0 Parallel to the plane of the first arc edge, the optical axis L of the objective lens 0 The included angle between the two ends of the shaft and the long axis direction is beta, and beta is more than or equal to 10 degrees and less than or equal to 30 degrees.
Exemplary, imaging System as illustrated in connection with FIG. 93 includes an objective lens (not shown in the figure, which is built into the imaging system 3) for magnifying the image of the edge of the object to be measured and improving the imaging quality. Setting the optical axis L of the objective lens 0 Parallel to the plane of the first arc edge, namely in the XY plane parallel to the surface of the object to be measured (silicon wafer), the optical axis L of the objective lens 0 The included angle between the incident light and the reflected light on the surface of the object to be measured is beta, i.e. the incident light and the reflected light on the surface of the object to be measured form a certain included angle beta, preferably, beta is more than or equal to 10 degrees and less than or equal to 30 degrees, so that the reflected light reflected by the surface of the object to be measured 4 can be ensured to exit through the slot 20 and then along the optical axis L of the objective lens 0 The image is formed in an imaging system after the image is amplified in the objective lens. Optionally, the imaging system further comprises a tube mirror and a CCD camera, the reflected light amplified by the objective lens is parallel incident to a photosensitive plane of the CCD camera through the tube mirror, and the CCD camera images the surface of the object to be detected, which can be a color or black-and-white image, so that edge defects can be identified conveniently.
On the basis of the above embodiment, optionally, the length of the slot along the long axis direction is L, which satisfies the following:
as illustrated in fig. 3-9, further, if the reflected light beam meeting the edge of the object to be measured (silicon wafer) can exit from the ellipsoidal mirror 2 into the objective lens, the length L of the slot 20 needs to be limited. Referring to fig. 8 and 9, the reflected light beam is emitted from the T point of the opening area of the slot 20, and l1=h/tan β, H is parallel to the shorter axis of the ellipse in the ellipse equation according to the angle β between the incident light beam and the reflected light beam, and H<2b,2b are the short axis length of the ellipsoidal mirror, and if the length L of the slot 20 is greater than L1+a-c, the length of the slot 20
When the device is used, the reflected light rays at the edge of an object to be detected (silicon wafer) can be satisfied and enter the objective lens from the ellipsoidal mirror 2. In practical silicon wafer edge detection applications, an area of the silicon wafer edge is detected, not just the edge vertex, and all incident light of- (180-2 alpha) needs to be in the detected area. At the upper partOn the basis of the embodiment, by reasonably adjusting the width 2h and the length L of the slot 20, firstly, the width 2h of the slot can meet the requirement that the included angle gamma between the connecting line of each point in the detection area of the object to be detected (the detection point of the detection area of the object to be detected is arranged at the second focal point F2) and the first arc edge S1 (shown as the point M in fig. 8) of the slot 20 or the second arc edge S2 (shown as the point N in fig. 8) of the slot 20 and the long axis direction is less than or equal to 2 alpha; and secondly, each point in the detection area of the object to be detected 4 can receive the reflected light rays reflected by each point of the reflecting surface in the elliptical mirror 2, so that the incident light rays of- (180-2 alpha) in the detection area of the object to be detected 3 are satisfied, and bright field illumination of the edge of the object to be detected is formed.
FIG. 10 shows an embodiment of the present invention provides an ellipsoidal mirror with an internal reflection surface having a scattering angle θ 1 Is a schematic diagram of (a). As shown in fig. 3-10, optionally, the light source 1 includes a point light source, and the internal reflection surface of the ellipsoidal mirror 2 includes scattering particles (not shown) for scattering the detection light reaching the internal reflection surface of the ellipsoidal mirror to form a scattered light beam; the scattering angle of the scattered light beam relative to the detected light is theta 1 The method comprises the following steps:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
As an example, referring to fig. 10, the light source 1 includes a point light source, and the point light source provided in the embodiment of the present invention refers to a light source that can uniformly emit light in all directions, such as an LED lamp. The point light source is arranged at the position of the first focus F1, and scattering particles are added on the inner reflecting surface of the ellipsoidal mirror 2, so that the inner reflecting surface of the ellipsoidal mirror 2 is made into a scattering surface with a certain scattering angle, and all the detection light rays emitted from the light source and incident on the inner reflecting surface of the ellipsoidal mirror 2 can be changed into light rays with a certain divergence angle theta after being scattered 1 Is present, i.e. there is scattered light relative to detected lightThe scattering angle of the line is theta 1 The angle of scattering θ of the internal reflection surface of the ellipsoidal mirror 2 1 。
Further, according to the size of the detection area 31 of the to-be-detected 3, the scattering surface formed by the scattering particles is adjusted, and the scattering angle theta of the scattered light beam relative to the detected light is adjusted 1 Enabling scattered light to cover the detected area 31. Specifically, the size of the detection region is known as w×t, where w is the length of the detection region of the object to be detected, and t is the width of the detection region of the object to be detected. The distance between a certain point P of the internal reflection surface of the ellipsoidal mirror 2 and the second focus F2 is l 1 And l 1 The beam scattered by point P, much greater than w and t, covers exactly the detection area 31. The divergence angle of the scattered light emitted from the P point relative to the incident detection light is theta 1 The intersection with the edge of the detection region 31 is K, Q, which satisfies
Where KQ is the distance between foci K and Q, known as l 1 Smaller theta 1 The larger the KQ, the larger θ 1 The larger the +.>
In the XZ plane in FIG. 10, according to the elliptic equation +.>
If the P point coordinates are (x, z), l 1 The expression of (2) is as follows:
wherein, -a is equal to or less than x is equal to or less than a, and when x=a, l 1 At least is l 1 =a-c, then θ 1 Maximum value of (2)
Setting the scattering angle +.>
By scattering angle theta 1 By limiting, each position point of the detected area of the object to be detected 4 can receive the reflected light from each position point of the internal reflection surface of the ellipsoidal mirror 2, and the included angle between the connecting line of each position point of the detecting area 31 of the object to be detected 4 and each position of the ellipsoidal reflection surface and the long axis direction (horizontal line) is further set to be 180-2 alpha to 180-2 alpha, so that each point in the detected area 31 can receive the incident light of 180-2 alpha to 180-2 alpha, and the edge bright field illumination is realized.
Alternatively, the scattering angle θ 1 The following are also satisfied:
further, the scattering angle theta of the scattered light beam relative to the detected light is defined 1 I.e. the angle of scattering θ of the internal reflecting surface of an elliptical mirror 1 Satisfy->
Excessive scattering angle θ 1 Some scattered light will go beyond the detection area 31, causing waste of light energy by directing the scattering angle θ 1 Is limited at
In the range, each point in the detection area 31 can receive incident light of (180-2 alpha) - (180-2 alpha), the light energy utilization rate is higher, the light energy utilization rate reaches more than 90%, the full utilization of the light source energy is realized, the imaging quality can be improved, and the defects of the detection area 31 can be identified.
Fig. 11 is a schematic view of a surface light source according to an embodiment of the present invention. As shown in conjunction with fig. 11, alternatively, the light source includes a surface light source; the diameter of the light source of the surface light source is D, and the following conditions are satisfied:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
As illustrated in connection with fig. 11, the light source 1 includes a surface light source, which refers to a light source having a light emitting area with a certain length and width, such as a flat light source. A circular area light source with the diameter D of the light source is selected, and because the light emitting surface of the light source 1 has a certain size, the light emitted from the light source 1 to any point of the internal reflection surface of the ellipsoidal mirror 2 has a certain divergence angle theta 2 Optionally, the internal reflecting surface of the ellipsoidal mirror 2 comprises a specular mirror. The divergent light beams incident to the mirror surface reflector are reflected to form a beam with the same divergence angle theta 2 At the position where the diverging light beam reaches the second focus F2 of the ellipsoidal mirror 2, the magnitude of the light emitting surface of the light source 1 is controlled to make the divergence angle of the light source 1 to each point of the internal reflection surface of the ellipsoidal mirror 2 be theta 2 Satisfy inequality of
So that the reflected light reflected by the internal reflection surface can cover the detection region 31 of the object 4 to be detected. Since the diameter of the circular light emitting surface of the light source 1 is D, the inequality is satisfied: />
I.e. < ->
Thereby meeting the requirements that the included angle between the connecting line of each position point in the detection area 31 and each position on the internal reflection surface of the ellipsoidal mirror 2 and the long axis direction (horizontal line) meets the requirements of- (180-2 alpha), ensuring that each point in the detection area 31 of the object 4 to be detected can receive the incident light of- (180-2 alpha) to form bright field illumination of the detection area 31, and under the condition of adopting a surface light source, the light energy utilization rate is still higher and reaches more than 90%, and realizing the full utilization of the light source energy.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (9)
1. The curved surface detection device is characterized by comprising a light source, an ellipsoidal mirror and an imaging system;
the ellipsoidal mirror is of a hollow structure, the surface of the ellipsoidal mirror comprises a slot, and the slot comprises a first arc edge and a second arc edge; the ellipsoidal mirror further comprises a central plane where the long axis is located, and the central plane is parallel to a plane where the first arc edge is located and a plane where the second arc edge is located respectively;
the light source is positioned on the first focal point of the long shaft and is used for emitting detection light; the object to be detected passes through the opening area of the slot and is positioned on the second focus of the long shaft, and the detection area of the object to be detected is at least partially in a curved surface; the detection light reaches the detection area of the object to be detected after being reflected by the internal reflection surface of the ellipsoidal mirror, and is reflected to form reflected light which is emitted through the slot;
the imaging system is positioned on the propagation path of the reflected light and is used for collecting the reflected light and imaging the detection area of the object to be detected according to the reflected light;
wherein, along the long axis direction of the ellipsoidal mirror, the maximum included angle between the connecting line of the second focus and any point on the first arc edge and the long axis direction and the maximum included angle between the connecting line of the second focus and any point on the second arc edge and the long axis direction are both gamma,
γ≤2α，0°＜α＜90°；
along the direction perpendicular to the plane where the first arc edge is located, the width of the slot is 2h, and the following conditions are satisfied:
wherein alpha is the minimum included angle between the tangential plane of the detection area of the object to be detected and the long axis direction, a is half of the long axis length of the ellipsoidal mirror, b is half of the short axis length of the ellipsoidal mirror, c is half of the distance between the first focus and the second focus of the ellipsoidal mirror long axis, and h is half of the width of the slot.
2. The curved surface detecting device according to claim 1, wherein the imaging system includes an objective lens, an optical axis of the objective lens is parallel to a plane in which the first arc edge is located, and an angle between the optical axis of the objective lens and the long axis direction is β, and β is 10 ° or more and 30 ° or less.
3. The curved surface detecting device according to claim 2, wherein the length of the slot along the long axis direction is L, satisfying:
4. the surface inspection apparatus of claim 2 wherein the imaging system further comprises a tube mirror and a CCD camera.
5. The curved surface detection device of claim 1, wherein said light source comprises a point light source;
the internal reflection surface of the ellipsoidal mirror comprises scattering particles, and the scattering particles are used for scattering the detection light reaching the internal reflection surface of the ellipsoidal mirror to form a scattered light beam;
the scattering angle of the scattered light beam relative to the detected light is theta 1 The method comprises the following steps:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
6. The surface inspection apparatus according to claim 5, wherein the scattering angle θ 1 The following is also satisfied:
7. the curved surface detection device according to claim 1, wherein the light source comprises a surface light source;
the diameter of the light source of the surface light source is D, and the following conditions are satisfied:
wherein w is the length of the detection area of the object to be detected, t is the width of the detection area of the object to be detected, a is half of the length of the long axis of the ellipsoidal mirror, and c is half of the distance between the first focus and the second focus of the long axis of the ellipsoidal mirror.
8. The curved surface detection device of claim 7, wherein said internal reflecting surface of said ellipsoidal mirror comprises a specular mirror.
9. The surface inspection apparatus of claim 1 wherein the light source comprises a bright field light source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210022328.8A CN114324365B (en) | 2022-01-10 | 2022-01-10 | Curved surface detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210022328.8A CN114324365B (en) | 2022-01-10 | 2022-01-10 | Curved surface detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114324365A CN114324365A (en) | 2022-04-12 |
| CN114324365B true CN114324365B (en) | 2023-06-23 |
Family
ID=81027396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210022328.8A Active CN114324365B (en) | 2022-01-10 | 2022-01-10 | Curved surface detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114324365B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB571567A (en) * | 1943-10-14 | 1945-08-30 | Wray Optical Works Ltd | Improvements relating to optical condenser systems |
| JP2006090747A (en) * | 2004-09-21 | 2006-04-06 | Mitsutoyo Corp | Surface-flaw inspection device |
| CN210776054U (en) * | 2019-12-03 | 2020-06-16 | 常州迈纳光电科技有限公司 | 360-degree reflective free-form surface shaping laser module |
| CN113533353A (en) * | 2021-08-20 | 2021-10-22 | 合肥御微半导体技术有限公司 | Defect detection device and defect detection method |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2999712B2 (en) * | 1996-03-29 | 2000-01-17 | 住友金属工業株式会社 | Edge defect inspection method and apparatus |
| JP2003077319A (en) * | 2001-09-05 | 2003-03-14 | Web Tec Kk | Lighting device |
| JP3936220B2 (en) * | 2002-03-28 | 2007-06-27 | 株式会社レイテックス | Edge inspection equipment |
| WO2004070370A1 (en) * | 2003-02-07 | 2004-08-19 | Nikon Corporation | Wafer tester |
| JP4663724B2 (en) * | 2005-08-10 | 2011-04-06 | 株式会社レイテックス | Edge inspection equipment |
| KR20090068056A (en) * | 2007-12-22 | 2009-06-25 | 주식회사 동부하이텍 | Apparatus and method for detecting and removing defects on wafer |
| CN107764831B (en) * | 2016-08-23 | 2020-09-25 | 杭州海康机器人技术有限公司 | Optical flat plate detection device |
| CN215297140U (en) * | 2021-04-20 | 2021-12-24 | 苏州灵析精密仪器有限公司 | Ellipsoidal laser reflection focusing module |
-
2022
- 2022-01-10 CN CN202210022328.8A patent/CN114324365B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB571567A (en) * | 1943-10-14 | 1945-08-30 | Wray Optical Works Ltd | Improvements relating to optical condenser systems |
| JP2006090747A (en) * | 2004-09-21 | 2006-04-06 | Mitsutoyo Corp | Surface-flaw inspection device |
| CN210776054U (en) * | 2019-12-03 | 2020-06-16 | 常州迈纳光电科技有限公司 | 360-degree reflective free-form surface shaping laser module |
| CN113533353A (en) * | 2021-08-20 | 2021-10-22 | 合肥御微半导体技术有限公司 | Defect detection device and defect detection method |
Non-Patent Citations (1)
| Title |
|---|
| 大离轴量凹面取样镜的设计;李红光;张彭舜;达争尚;;光子学报(第05期);第89-92页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114324365A (en) | 2022-04-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4555635A (en) | Surface flaw inspection apparatus for a convex body | |
| US9316596B2 (en) | Apparatus and method for inspecting matter and use thereof for sorting recyclable matter | |
| US6798503B2 (en) | Edge flaw inspection device | |
| WO2012121323A1 (en) | Optical characteristic measurement device | |
| US4541715A (en) | Apparatus for detecting contaminants on the reticle of exposure system | |
| JP2010112786A (en) | Illumination apparatus and appearance inspection apparatus having the same | |
| JP2009068903A (en) | Surface inspection method and surface inspection device | |
| US8514385B2 (en) | Device and method for inspecting an object | |
| JP2008014848A (en) | Surface inspection method and surface inspecting device | |
| US9568437B2 (en) | Inspection device | |
| US7061598B1 (en) | Darkfield inspection system having photodetector array | |
| JP2002328094A (en) | Led ring lighting and image inspecting device with it | |
| JP2006138830A (en) | Surface defect inspection device | |
| CN114324365B (en) | Curved surface detection device | |
| JP2006017685A (en) | Surface defect inspection device | |
| US11249028B2 (en) | Apparatus for inspecting object surface | |
| JP2000295639A (en) | Lighting device for inspecting solid-state image pickup element and adjustment tool used for the same | |
| JPS5961704A (en) | Dimension measuring apparatus | |
| JP3102362U (en) | Mirror inspection equipment | |
| JP2022045523A (en) | Defect inspection device | |
| JP2023139653A (en) | Optical inspection apparatus, processing device, optical inspection method, and optical inspection program | |
| JPH03291552A (en) | Surface defect inspection device | |
| JPH0131958Y2 (en) | ||
| JPS59180413A (en) | Surface-defect inspecting method | |
| KR20090110232A (en) | Foreign particle inspection apparatus, exposure apparatus, and method of manufacturing device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |