CN217505680U - Optical detection system and optical detection device - Google Patents
Optical detection system and optical detection device Download PDFInfo
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- CN217505680U CN217505680U CN202221055010.1U CN202221055010U CN217505680U CN 217505680 U CN217505680 U CN 217505680U CN 202221055010 U CN202221055010 U CN 202221055010U CN 217505680 U CN217505680 U CN 217505680U
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Abstract
The utility model discloses an optical detection system and optical detection device, wherein, optical detection system includes: the device comprises a bearing table, an illumination unit and a control unit, wherein the illumination unit is used for emitting incident beams to an object to be measured and comprises a light source module, a light changing module and an objective lens which are sequentially arranged along the transmission path of the incident beams; the light changing module comprises a light shading plate, and the light shading plate is used for diffracting an incident light beam entering the objective lens to form annular incident light; the imaging unit is used for acquiring an image of an object to be detected and comprises an objective lens, an optical filter, a condensing lens and an image acquisition module which are sequentially arranged along a transmission path of an emergent light beam; the filter is used for filtering out reflected light in the emergent light beam before the emergent light beam enters the image acquisition module. The utility model discloses need not to set up dark field light source in the side direction of micro-detection equipment, avoided the occupation to micro-detection device lateral space, can realize the outfit of high power light source, promote dark field imaging effect.
Description
Technical Field
The utility model relates to a micro-detection area, especially optical detection system and optical detection device.
Background
With the deepening and popularization of industrial automation and intelligence, the use of Automatic Optical Inspection (AOI) instead of the traditional manual visual Inspection has become a technological development trend. The 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 and positioning capability of the AOI equipment.
Dark field microscopy, a special microscopy technique in electron microscopy, involves passing light or electrons, excluding the object under observation, into an objective lens, so that the background of the field of view observed in the eyepiece is black, and only the edges of the object are bright. By using the method, micro-particles as small as 4-200nm can be seen, and the resolution ratio can be 50 times higher than that of the common microscopy. The dark field microscopy is used for detecting the surface of the semiconductor wafer and is an important means for detecting the surface of the wafer.
In the dark field imaging process of the optical detection system in the prior art, a light source generally enters from the oblique direction of an object to be detected, and an incident light beam is reflected by the object to be detected, then is reflected to an image acquisition module through an objective lens and forms a dark image. In the whole imaging process, the image acquisition module can only receive the diffuse reflection light beam in the reflection light beam of the object to be measured to form an image in the process of forming a dark image.
In the prior art, in order to avoid that reflected light in emergent light reflected by an object to be detected enters a dark field image acquisition module to influence dark field imaging, the dark field detection light beam does not generally pass through an objective lens on an incident path, a dark field light source is arranged on the side direction of detection equipment, the dark field light source directly irradiates the object to be detected from an oblique direction, emergent light reflected by the object to be detected comprises reflected light and diffuse reflected light, and due to oblique incidence, the reflected light is generally directly reflected to the outside of the objective lens, and only the diffuse reflected light enters the objective lens and finally forms an image through an imaging unit.
In order to reflect the reflected light to the outside of the objective lens, the dark field light source can only be arranged laterally in the prior art, and when the dark field light source is arranged laterally, more lateral space of the device is generally occupied, so that the operation and the use are inconvenient. In addition, the lateral light source is easily shielded by the objective lens in the process of irradiating the object to be measured, so that the dark field light source can irradiate the object to be measured only by inclining at a larger incident angle, and the arrangement of the dark field light source is not facilitated. In addition, the above various arrangements make it generally difficult to provide the dark field light source with high power, and the low power of the dark field light source will ultimately affect the effect of dark field imaging.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an optical detection system to solve not enough among the prior art, it can need not to set up dark field light source in the side direction of micro-detection equipment on the basis of guaranteeing dark field effective imaging, has avoided occuping to micro-detection device lateral space, has made things convenient for the operation, and the outfit of realization high power light source that can be better, and then promotes dark field imaging effect.
The utility model provides an optical detection system, include: the bearing table is used for bearing an object to be tested;
the illumination unit is used for emitting incident beams to an object to be measured and comprises a light source module, a light changing module and an objective lens which are sequentially arranged along a transmission path of the incident beams; the light changing module comprises a light shielding plate, and the light shielding plate is used for diffracting an incident light beam entering the objective lens to form annular incident light;
the imaging unit is used for receiving the emergent light beam reflected by the object to be detected and acquiring an image of the object to be detected, and comprises the objective lens, the optical filter, the condensing lens and the image acquisition module which are sequentially arranged along the transmission path of the emergent light beam; the optical filter is used for filtering reflected light in the emergent light beam before the emergent light beam enters the image acquisition module; the condenser lens is used for focusing the emergent light beam on the image acquisition module.
Further, the light filter includes the diaphragm, the diaphragm has the diaphragm body and forms the circular light trap of a plurality of not unidimensional on the diaphragm body, the diaphragm body is used for blockking the reverberation in the emergent beam, the size of circular light trap is not more than the size of shading plate, a plurality of circular light trap are followed the circumference of diaphragm body is arranged.
Further, the light changing module is also provided with a bearing disc and a circular perforation arranged on the bearing disc, the light shielding plate is positioned at the center of the circular perforation and fixed on the bearing disc, and the diameter of the light shielding plate is smaller than the size of the circular perforation so as to form an annular gap between the light shielding plate and the bearing disc.
Furthermore, the light screen is provided with a plurality of and have different sizes, bear and be provided with a plurality of not circular perforation of equidimension on the dish, each all be provided with the light screen of looks adaptation in the circular perforation.
Further, the imaging unit is provided with a relay system arranged between the optical filter and the objective lens, the relay system comprises a first convex lens and a second convex lens which are sequentially arranged on a transmission path of the emergent light beam, and a focus of the first convex lens coincides with a focus position of the second convex lens.
The utility model discloses another embodiment still discloses an optical detection device, include: the optical detection system;
when the light shielding plate is positioned on a transmission path of incident light beams, the incident light beams entering the objective lens are diffracted to form dark field detection light beams;
when the shading plate moves out of a transmission path of an incident beam, the incident beam entering the objective lens forms a bright field detection beam;
the imaging unit is further configured to receive the bright field outgoing beam reflected by the object to be measured and collect a bright field image of the object to be measured, and the light condensing module is configured to focus the bright field outgoing beam incident from the objective lens on the image collecting module when the bright field image is collected;
when a dark field image is collected, the optical filter is arranged between the condenser lens and the objective lens, and the condenser lens is used for focusing diffuse reflection light which is not filtered out by the optical filter in dark field emergent light beams on the image collection module.
Furthermore, the light changing module is also provided with a plurality of bright field light holes with different sizes, when the shading plate moves out of the transmission path of the incident light beam, the bright field light holes are positioned in the transmission path of the incident light beam, the light changing module is provided with a bearing disc, the shading plate and the bright field light holes are both arranged on the bearing disc, and the shading plate and the bright field light holes are distributed along the circumferential direction of the bearing disc.
Further, the image acquisition module comprises a bright field image collector for acquiring a bright field image and a dark field image collector for acquiring a dark field image, and the condenser lens comprises a bright field condenser lens arranged on the front side of the bright field image collector and a dark field condenser lens arranged on the front side of the dark field image collector;
when a bright field image is collected, a bright field emergent light beam emitted from the objective lens reaches a bright field image collector through a bright field condensing lens along a bright field imaging light path;
when a dark field image is collected, a dark field emergent light beam emitted from the objective lens sequentially passes through the optical filter and the dark field condenser lens along a dark field imaging light path to reach the dark field image collector.
Further, the imaging unit is also provided with an imaging light splitting module which is simultaneously positioned on a transmission path of the bright field emergent light beam and a transmission path of the dark field emergent light beam;
when a bright field image is collected, the imaging light splitting module is used for transmitting part of the bright field emergent light beam to the bright field image collector; when a dark field image is collected, the imaging light splitting module is used for reflecting part of dark field emergent light beams to the dark field image collector;
or when the bright field image is collected, the imaging light splitting module is used for reflecting part of the bright field emergent light beam to the bright field image collector; and when a dark field image is collected, the imaging light splitting module is used for transmitting part of the dark field emergent light beam to the dark field image collecting module.
Furthermore, the bright field image collector and the dark field image collector are arranged in parallel, the imaging unit is further provided with a reflector arranged on the dark field imaging light path, and a dark field emergent light beam emitted from the imaging light splitting module is incident on the reflector in a direction inclined by 45 degrees with the plane where the reflector is located.
Compared with the prior art, the embodiment of the utility model provides an in because incident beam from the light source module sends is from the incident directly over the determinand to shelter from the filtration to the reverberation on the transmission path of reverberation beam, thereby need not to set up dark field light source in the side direction of micro-detection equipment on the basis of guaranteeing dark field effective imaging, avoided taking up micro-detection device lateral space, made things convenient for the operation. Meanwhile, the dark field light source does not need to be arranged in the lateral direction, and the high-power light source is not limited too much when being configured, so that the high-power light source can be better equipped, and the dark field imaging effect is further improved.
Drawings
Fig. 1 is a schematic structural diagram of an optical inspection system disclosed in an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an optical module in the optical detection system disclosed in the embodiment of the present invention;
fig. 3 is a schematic structural diagram of an optical filter in an optical detection system according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an optical detection apparatus disclosed in an embodiment of the present invention;
description of reference numerals: 1-a bearing platform, 2-a light source module, 3-a light changing module, 31-a light shading plate, 32-a bearing plate, 33-an annular gap, 34-a bright field light hole, 4-an objective lens, 5-a light filter, 51-a diaphragm body, 52-a circular light hole, 6-a condenser lens, 61-a bright field condenser lens, 62-a dark field condenser lens, 7-an image acquisition module, 71-a bright field image acquisition device, 72-a dark field image acquisition device, 8-a relay system, 81-a first convex lens, 82-a second convex lens, 9-a light splitting module, 11-a light reflecting module, 12-an imaging light splitting module and 13-a reflector.
Detailed Description
The embodiments described below by referring to the drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.
The embodiment of the utility model discloses optical detection system, this optical detection system can be used for wafer surface defect's detection. Specifically, as shown in fig. 1 to 3, the optical detection system includes: the device comprises a bearing table 1, an illuminating unit and an imaging unit, wherein the bearing table 1 is used for bearing an object to be detected, the illuminating unit emits an incident beam to the bearing table 1, the incident beam is used as a detection beam to irradiate on the object to be detected, the incident beam is reflected by the object to be detected after being irradiated on the object to be detected to form a reflected beam, and the reflected beam finally forms a dark field image after being received by the imaging unit.
Specifically, the illumination unit comprises a light source module 2, a light changing module 3 and an objective lens 4 which are sequentially arranged along the transmission path of the incident light beam; the light source module 2 is used for emitting an incident light beam, the emitted incident light beam forms a dark field detection light beam after passing through the light changing module 3, and then reaches the object to be measured of the bearing table 1 through the objective lens 4, and it can be understood that the objective lens 4 is placed above the bearing table 1 to be used for observing the object to be measured.
The light changing module 3 is used for transforming the incident light beam into the required detection light beam, in this embodiment, because dark field imaging is required, the light changing module 3 comprises a light shielding plate 31, and the light shielding plate 31 is used for diffracting the incident light beam into annular incident light before entering the objective lens 4.
The light source module 2 emits a light source which is generally a point light source, in this embodiment, a kohler illumination light source is adopted for better achieving a dark field imaging effect, and the kohler illumination light source has high power and can better achieve the imaging effect. The light shielding plate 31 shields the center position of the point light source, so that the incident light beam emitted by the light source module 2 is diffracted to form annular incident light, and the annular incident light is used as a dark field detection light beam and irradiates an object to be measured on the bearing table 1 through the objective lens 4.
In the embodiment, the original point light source is diffracted to form the annular light source, and then the annular light source enters the objective lens 4, and the annular incident light is focused on the point to be measured after being focused by the objective lens 4. The process that the dark field detection light beam is focused by the objective lens 4 is substantially to enable the annular detection light beam to irradiate the point to be detected in an annular mode from the peripheral direction of the object to be detected, and the irradiation brightness of the point to be detected can be effectively improved.
The imaging unit is used for receiving the emergent light beam reflected by the object to be detected and acquiring a dark field image of the object to be detected, and comprises the objective lens 4, the optical filter 5, the condensing lens 6 and the image acquisition module 7 which are sequentially arranged along the transmission path of the emergent light beam; the optical filter 5 is used for filtering reflected light in the emergent light beam before the emergent light beam enters the image acquisition module 7; the condenser lens 6 is used to focus the emergent light beam on the image collection module 7.
The dark field detection light beam is reflected by an object to be detected to form an emergent light beam, the emergent light beam is reflected to the objective lens 4, the emergent light beam from the objective lens 4 is filtered by the optical filter 5 to filter the reflected light in the emergent light beam, after the filtered emergent light beam passes through the condenser lens 6, the condenser lens 6 focuses the residual diffuse reflection light after filtering the emergent light beam on the image acquisition module 7, and finally a dark field image is formed.
In the prior art, in order to avoid that reflected light in emergent light reflected by an object to be detected enters a dark field image acquisition module to influence dark field imaging, the dark field detection light beam does not generally pass through an objective lens 4 on an incident path, but a dark field light source is arranged on the side direction of detection equipment, the dark field light source directly irradiates on the object to be detected from an oblique direction and forms an emergent light beam after being reflected by the object to be detected, the formed emergent light beam comprises reflected light and diffuse reflected light, and due to oblique incidence, the reflected light is generally directly reflected outside the objective lens, and only the diffuse reflected light enters the objective lens and finally forms an image through an imaging unit.
In order to reflect the reflected light to the outside of the objective lens, the dark field light source can only be arranged in the lateral direction in the prior art, and the dark field light source generally occupies more lateral space of the device when being arranged in the lateral direction, so that the dark field light source is inconvenient to operate and use. When the microscope objective works, the distance from the bearing platform is generally close, especially the distance between the objective with high magnification and the bearing platform is about 10mm, on the basis, if a dark field light source is arranged in the lateral direction, great inconvenience is brought to the operation of the operation platform, and when the distance is close, the lateral light source is easily shielded by the objective when irradiating an object to be measured, the dark field light source can irradiate the object to be measured only by inclining to a large incident angle, and the arrangement of the dark field light source is not facilitated. In addition, the above various arrangements make it generally difficult to provide the dark field light source with high power, and the low power of the dark field light source will ultimately affect the effect of dark field imaging.
In the embodiment, the incident light beam emitted by the light source module 2 is diffracted by the light changing module 3 to form an annular dark field detection light beam, the dark field detection light beam is incident on the object to be measured on the bearing table 1 through the entrance pupil of the objective lens 4, and after being reflected by the object to be measured, the optical filter 5 is arranged on the transmission path of the reflected light beam to filter the reflected light in the reflected light beam, so that the reflected light beam finally received by the image acquisition module 7 is mainly diffuse reflected light in the reflected light beam, and the influence of the reflected light in the reflected light beam on dark field imaging is avoided.
In this embodiment, the incident light beam emitted from the light source module 2 is incident from directly above the object to be detected, and the reflected light is shielded and filtered on the transmission path of the reflected light beam, so that a dark field light source is not required to be arranged in the lateral direction of the microscopic detection device on the basis of ensuring the effective imaging of the dark field, the occupation of the lateral space of the microscopic detection device is avoided, and the operation is facilitated. Meanwhile, the dark field light source does not need to be arranged in the lateral direction, and the high-power light source is not limited too much when being configured, so that the high-power light source can be better equipped, and the dark field imaging effect is further improved.
In the present embodiment, the optical filter 5 includes a diaphragm having a diaphragm body 51 and a circular light-transmitting hole 52 formed on the diaphragm body 51, the diaphragm body 51 being configured to block reflected light in the outgoing light beam, and the circular light-transmitting hole 52 being configured to transmit diffuse reflected light in the reflected light beam.
Because the incident beam of the point light source is diffracted to form an annular dark field detection beam under the action of the light changing module 3, the annular dark field detection beam enters the objective lens 4 and then irradiates on the object to be detected, and the annular dark field detection beam can be converged and focused on the object to be detected under the action of the objective lens 4. The reflected light beam formed by the annular dark field detection light beam reflected by the object to be detected comprises annular reflected light and diffuse reflected light, the annular reflected light is emitted to the image acquisition module 7 through the objective lens 4, and the reflected light is shielded by the diaphragm body 51 in the optical filter 5 before entering the image acquisition module 7.
In order to enable the diaphragm body 51 to block the reflected light, the size of the circular light transmission hole 52 on the diaphragm body 51 is not larger than the size of the light shielding plate 31 on the light changing module 3, so that the reflected light cannot transmit through the circular light transmission hole 52, and the circular light transmission hole 52 only can transmit the diffuse reflected light in the dark field detection light beam and finally form a dark field image on the image acquisition module 7.
Further, a plurality of circular light holes 52 with different sizes are formed in the diaphragm body 51, and the circular light holes 52 are arranged along the circumferential direction of the diaphragm body 51. Since one detection device is provided with the objective lenses 4 with different magnifications, different objective lenses have entrance pupils with different sizes, the incident annular dark field detection light beams required by the entrance pupils with different sizes are also different, and the annular reflected light formed after final reflection is also different in size.
The round light holes 52 with different sizes are arranged in the embodiment, so that the objective lens 4 with different magnification factors can be better suitable, and the applicability of the equipment is improved. And a plurality of circular light holes 52 are arranged along the circumferential direction of the diaphragm body 51, so that different circular light holes 52 can be switched better.
When the light changing module 3 diffracts the incident light beam emitted from the light source module 2, the incident light beam can be shielded only by the light shielding plate 31, and the diffracted light is diffracted out from the circumferential edge of the light shielding plate 31. In this embodiment, in order to better present the dark field detection light beam, the light changing module 3 further has a carrying disc 32 and a circular through hole provided on the carrying disc 32, the light shielding plate 31 is positioned at the center of the circular through hole and fixed on the carrying disc 32, and the diameter of the light shielding plate 31 is smaller than the size of the circular through hole to form an annular gap 33 between the light shielding plate 31 and the carrying disc 32.
In this embodiment, the light shielding plate 31 may be fixedly connected to the bearing plate 32 through a plurality of lateral connecting posts, the lateral connecting posts extend along the radial direction of the light shielding plate 31, the lateral connecting posts partition the annular gap 33, in the specific embodiment, the light shielding plate 31 may be integrally formed with the bearing plate 32, the annular gap 33 is formed by a plurality of arc-shaped through holes excavated on the bearing plate 32, and the middle of the plurality of arc-shaped through holes relatively forms the light shielding plate 31.
In another embodiment, the light shielding plate 31 may be a structure separated from the carrier plate 32, and when the light shielding plate 31 moves to the position of the carrier plate 32, the center of the circular through hole on the carrier plate 32 is shielded to form a dark field detection beam, and when the light shielding plate 31 moves away from the position of the circular through hole of the carrier plate 32, the dark field detection beam is formed.
The formation of the dark-field detection beam by diffraction in the annular slit 33 enables a better enhancement of the dark-field detection beam, it being understood that the size of the annular slit 33 for enabling the dark-field detection beam to enter the objective 4 is adapted to the size of the entrance pupil of said objective 4.
Correspondingly, in order to adapt to the objective lenses 4 with different magnifications, the light shielding plates 31 are provided with a plurality of holes with different sizes, the bearing disc 32 is provided with a plurality of circular through holes with different sizes, and each circular through hole is internally provided with the light shielding plate 31 which is matched with the circular through hole.
The annular gap 33 is formed between each light shielding plate 31 and the inner wall of the corresponding circular through hole, the size of the circular through hole determines the size of the outer diameter of the annular gap 33, the size of the light shielding plate 31 is influenced by the entrance pupil of the objective lens 4, the width of the annular gap 33 is influenced, the irradiation effect of the dark field detection light beam is influenced by the width of the annular gap 33, and in principle, the narrower the annular gap 33 is, the better the dark field detection light beam is formed by diffraction.
In order to conveniently realize the switching use of different light shielding plates 31, the bearing plate 32 has a circular shape, and a plurality of light shielding plates 31 are arranged along the circumferential direction of the bearing plate 32.
The imaging unit further has a relay system 8 disposed between the optical filter 5 and the objective lens 4, the relay system 8 includes a first convex lens 81 and a second convex lens 82 sequentially disposed on a transmission path of the outgoing beam, and a focal point of the first convex lens 81 coincides with a focal point of the second convex lens 82.
The incident light and the emergent light of the relay system 8 are parallel light, so that the light of the reflected light beam can be compensated and adjusted, the reflected light beam can be better transmitted to the optical filter 5, and the imaging precision is ensured.
In this embodiment, the optical detection system further has a light splitting module 9 located on both the transmission path of the incident light beam and the transmission path of the emergent light beam, where the light splitting module 9 is configured to reflect a part of the incident light beam to the objective lens 4 and transmit a part of the emergent light beam to the image capturing module 7;
in a specific embodiment, the splitting module 9 includes a half mirror disposed on the transmission path of the outgoing beam, the half mirror is used for transmitting part of the outgoing beam, and the outgoing beam enters in a direction inclined by 45 ° with respect to the plane of the half mirror;
meanwhile, the half mirror is used for reflecting part of incident light beams, and the incident light beams are incident towards a direction which is inclined by 45 degrees with the plane where the half mirror is located.
Incident light beams from the light source module 2 form dark field detection light beams under the action of the light changing module 3, the direction of the dark field detection light beams entering the semi-transparent mirror is perpendicular to the emitting direction of the semi-transparent mirror reflected incident light beams, the objective lens 4 is right positioned in the direction of the semi-transparent mirror reflected incident light beams, therefore, reflected light beams reflected by an object to be measured are emitted from the objective lens 4 and then enter the semi-transparent mirror along the direction parallel to the semi-transparent mirror reflected incident light beams, and then enter the image acquisition module 7 after being transmitted by the semi-transparent mirror. In the above embodiment, the plane of the half mirror is substantially inclined at 45 ° to the incident direction of the incident beam, and the plane of the half mirror is also inclined at 45 ° to the incident direction of the reflected beam.
In the embodiment, since the image capturing module 7 is generally disposed on the upper side of the plummer 1, and the objective lens 4 is disposed between the image capturing module 7 and the plummer 1, the emergent beam from the objective lens 4 is emitted upward in a generally vertical direction, and the emergent beam is transmitted in a direction of the image capturing module 7 after reaching the half mirror. Accordingly, the incident light beam emitted from the light source module 2 is incident on the half mirror from the transverse direction, and is reflected by the half mirror into the entrance pupil of the objective lens 4.
It is understood that in another embodiment, the beam splitting module 9 is configured to transmit a part of the incident beam to the objective 4 and reflect a part of the emergent beam to the image capturing module 7. The difference between this embodiment and the above embodiment is only that the positions of the light source module 2 and the image capturing module 7 are exchanged, and detailed description is omitted.
In order to facilitate the arrangement of the light source module 2, the light source module 2 is generally arranged above the plummer 1, the light source module 2 emits an incident light beam downwards along the vertical direction, and in order to facilitate the incidence of the incident light beam, the optical detection system further includes a light reflecting module 11, and the light reflecting module 11 is configured to reflect the incident light beam incident from the light source module 2 from the vertical direction to the transverse direction and to emit the incident light beam onto the light splitting module 9 along the transverse direction.
The reflection module 11 may be a reflective mirror disposed on the incident light path, and the incident light beam emitted from the light source module 2 enters in a direction inclined by 45 ° with respect to the plane where the light emitting mirror is located;
the incident beam is reflected by the reflecting module 11 after passing through the reflecting module 11, the reflected incident beam is incident on the half mirror on the light splitting module 9 along the transverse direction and then reflected, and thus the incident beam which is incident along the vertical direction after two 45-degree reflections enters the entrance pupil of the objective lens 4 along the vertical direction again. It can be understood that the half mirror of the light splitting module 9 and the reflective mirror of the light reflecting module 11 are in the same horizontal direction, and the reflective surfaces of the two are opposite.
The utility model discloses another embodiment still discloses an optical detection device, as shown in FIG. 1, include: the optical detection system; the microscopic detection device can realize dark field imaging and bright field imaging of the object to be detected. In the microscopic detection device, the bright field detection light source and the dark field detection light source adopt the same light source and share one set of light path system, so that the structural design is more compact.
When the light-shielding plate 31 is positioned on the transmission path of the incident light beam, the incident light beam entering the objective lens 4 is diffracted to form a dark field detection light beam;
when the light shielding plate 31 moves out of the transmission path of the incident light beam, the incident light beam entering the objective lens 4 forms a bright field detection light beam;
the imaging unit is further configured to receive the bright field outgoing beam reflected by the object to be measured and collect a bright field image of the object to be measured, and when the bright field image is collected, the light condensing module 6 is configured to focus the bright field outgoing beam incident from the objective lens on the image collecting module 7;
when a dark field image is collected, the optical filter 5 is arranged between the condenser lens 6 and the objective lens, and the condenser lens 6 is used for focusing diffuse reflection light which is not filtered by the optical filter 5 in dark field emergent light beams on the image collection module 7.
When in bright field imaging, the light shielding plate on the light changing module 3 moves out of the transmission path of the incident beam, the point-shaped incident beam emitted from the light source module 2 directly enters the entrance pupil of the objective lens 4 and irradiates on the object to be measured on the bearing table 1 through the objective lens 4, the bright field emergent beam formed after being reflected by the object to be measured enters the image acquisition module 7 through the objective lens 4, the filter 5 is not needed to be arranged when in bright field imaging, and the bright field emergent beam focuses the light reflected by the object to be measured on the image acquisition module 7 through the condensing lens 6 for imaging.
It can be understood that, in the embodiment, the incident light path of the light source module 2 further has a plurality of light splitting modules to change the transmission of the light path, for example, in the embodiment of the present application, the incident light beam emitted from the light source module 2 is firstly reflected by the reflector on the light reflecting module 11 to the half mirror on the light splitting module 9, and then reflected by the half mirror on the light splitting module 9 to enter the entrance pupil of the objective lens 4.
Accordingly, the bright field reflected light beam also passes through the plurality of light splitting modules or the light adjusting module during the incident process on the image acquisition module 7. In a specific embodiment, the bright field reflected light beam emitted from the objective lens 4 is transmitted through the half mirror on the beam splitting module 9 and enters the relay system 8, and the bright field emitted light beam after adjustment by the relay system 8 enters the condenser lens 6.
In the dark field imaging, the light shielding plate 31 of the light changing module 3 is moved into the transmission path of the incident light beam, meanwhile, the optical filter 5 is arranged on the transmission path of the dark field reflected light beam, the point incident light beam emitted from the light source module 2 is diffracted to form an annular dark field incident light beam under the action of the light shielding plate 31 on the light changing module 3, the dark field incident light beam enters the entrance pupil of the objective lens 4, and irradiates on the object to be measured on the bearing table 1 through the objective lens 4, the emitted light beam of the dark field formed after being reflected by the object to be measured enters towards the image acquisition module 7 through the objective lens 4, before entering the image pickup module 7, the dark field outgoing light beam passes through the optical filter 5, the reflected light in the dark field outgoing light beam is blocked in the optical filter 5, only the diffuse reflected light in the dark field outgoing light beam enters the image pickup module 7, and further, the diffusely reflected light needs to be focused on the image capturing module 7 through the condenser lens 6 for imaging before entering the image capturing module 7.
It can be understood that the light path may need to be changed by a plurality of light splitting modules during the transmission of the dark field detection beam to the objective 4, which is consistent with the bright field imaging and will not be described herein. Similarly, the dark-field reflected light beam also needs to pass through the corresponding light splitting module or the light path adjusting module in the process of being transmitted to the image acquisition module 7, which is also consistent with the bright-field imaging, and is not described herein again.
In order to conveniently realize the switching of the bright field imaging and the dark field imaging, in the present embodiment, the light changing module 3 further has a bright field light transmitting hole 34, and when the light shielding plate 31 moves out of the transmission path of the incident light beam, the bright field light transmitting hole 34 is located in the transmission path of the incident light beam. For convenience of operation, the light changing module 3 has a carrying tray 32, the light shielding plate 31 and the bright field light holes 34 are both disposed on the carrying tray 32, and the light shielding plate 31 and the bright field light holes 34 are arranged along the circumferential direction of the carrying tray 32.
Through the arrangement of the structure, the free switching of the bright field light-transmitting holes 34 and the light shielding plate 31 on the transmission path of incident light beams can be realized through the rotation of the bearing disc 32. When the bright field light-transmitting hole 34 is located in the transmission path of the incident light beam, the incident light beam entering the objective lens 4 forms a bright field detection light beam; it should be noted that, when there is no light-changing module 3 in the bright-field imaging, the incident light beam emitted from the light source module 2 may be directly used as the bright-field detection light beam when there is no light-changing module 3, and here, the light-shielding plate 31 and the bright-field light-transmitting hole 34 are disposed on the light-changing module 3 only for the convenience of switching the light-shielding plate 31.
Further, a plurality of bright field light transmission holes 34 with different sizes are arranged on the bearing disc 32, and the plurality of bright field light transmission holes 34 are arranged along the circumferential direction of the bearing disc 32. The plurality of different bright field light holes 34 correspond to the objective lens 4 with different magnification factors, so that the applicability of the device is improved.
In the imaging process, bright field imaging and dark field imaging can be imaged in the same image acquisition module 7, so that the arrangement of the structure can effectively simplify equipment. In another embodiment, as shown in fig. 4, the image capturing module 7 may be provided with two image capturing devices, namely a bright field image capturing device 71 for capturing a bright field image and a dark field image capturing device 72 for capturing a dark field image, and correspondingly, the condenser lens 6 includes a bright field condenser lens 61 arranged in front of the bright field image capturing device 71 and a dark field condenser lens 62 arranged in front of the dark field image capturing device;
when a bright field image is collected, a bright field emergent light beam emitted from the objective lens 4 reaches the bright field image collector 71 through the bright field condenser lens 61 along a bright field imaging optical path;
when a dark field image is collected, a dark field emergent light beam emitted from the objective lens 4 sequentially passes through the optical filter 5 and the dark field condenser lens 62 along a dark field imaging optical path to reach the dark field image collector 72.
The imaging unit is further provided with an imaging light splitting module 12 which is positioned on a transmission path of the bright field outgoing light beam and a transmission path of the dark field outgoing light beam at the same time, and when a bright field image is collected, the imaging light splitting module 12 is used for transmitting part of the bright field outgoing light beam to the bright field image collector 71; when collecting a dark field image, the imaging beam splitting module 12 is configured to reflect a part of the dark field outgoing beam to the dark field image collector 72;
the imaging light splitting module 12 includes a half-mirror disposed on the transmission path of the bright field outgoing beam, and when collecting a bright field image, the half-mirror is used to transmit the bright field outgoing beam, and the bright field outgoing beam is incident in a direction inclined by 45 degrees with the plane of the half-mirror;
when a dark field image is collected, the half-mirror is used for reflecting a dark field emergent light beam, and the dark field emergent light beam is emergent in a direction which is inclined by 45 degrees with the plane of the half-mirror.
During bright field imaging, part of the bright field outgoing light beam emitted from the objective lens 4 is transmitted through the half mirror of the imaging beam splitting module 12, then enters the bright field condenser lens 61, is focused by the bright field condenser lens 61, and then is imaged on the bright field image collector 71.
During dark field imaging, part of dark field outgoing light beams emitted from the objective lens 4 are reflected by the half mirror of the imaging light splitting module 12 and then partially incident on the dark field image collector 72, and meanwhile, part of the dark field outgoing light beams are transmitted by the half mirror of the imaging light splitting module 12 and then imaged on the bright field image collector 72, and at the moment, a bright field image can be formed on the bright field image collector 72 again, so that the recheck of bright field imaging can be realized in the dark field imaging process, and the detection effect is better improved.
In another embodiment, when collecting the bright field image, the imaging splitting module 12 is configured to reflect a part of the bright field outgoing beam to the bright field image collector 71; and the imaging beam splitting module 12 is configured to transmit a part of the dark field outgoing beam to the dark field image collector 72 when collecting the dark field image. The detailed light path arrangement is not described herein, and the difference between the light field image collector 71 and the dark field image collector 72 is only that the positions of the light field image collector 71 and the dark field image collector 72 are exchanged, and it can be understood that some structural components adapted to the light field image collector 71 and the dark field image collector 72 in the process of exchanging them also need to be exchanged together.
In order to conveniently realize the arrangement of the image collector 7, the bright field image collector 71 and the dark field image collector 72 are arranged in parallel and are both arranged above the plummer 1, the imaging unit further comprises a reflector 13 arranged on the dark field imaging optical path, and a dark field outgoing beam emitted from the imaging light splitting module is incident on the reflector 13 in a direction inclined by 45 degrees with the plane where the reflector 13 is located.
The structure, features and effects of the present invention have been described in detail above according to the embodiment shown in the drawings, and the above description is only the preferred embodiment of the present invention, but the present invention is not limited to the implementation scope shown in the drawings, and all changes made according to the idea of the present invention or equivalent embodiments modified to the same changes should be considered within the protection scope of the present invention when not exceeding the spirit covered by the description and drawings.
Claims (10)
1. An optical inspection system, comprising:
the bearing table is used for bearing an object to be tested;
the illumination unit is used for emitting incident beams to an object to be measured and comprises a light source module, a light changing module and an objective lens which are sequentially arranged along a transmission path of the incident beams; the light changing module comprises a light shading plate, and the light shading plate is used for diffracting an incident light beam entering the objective lens to form annular incident light;
the imaging unit is used for receiving the emergent light beam reflected by the object to be detected and acquiring an image of the object to be detected, and comprises the objective lens, the optical filter, the condensing lens and the image acquisition module which are sequentially arranged along the transmission path of the emergent light beam; the optical filter is used for filtering reflected light in the emergent light beam before the emergent light beam enters the image acquisition module; the condenser lens is used for focusing the emergent light beam on the image acquisition module.
2. The optical detection system of claim 1, wherein: the light filter includes the diaphragm, the diaphragm has the diaphragm body and forms the circular light trap of a plurality of not unidimensional on the diaphragm body, the diaphragm body is used for blockking the reverberation in the emergent beam, the size of circular light trap is not more than the size of shading plate, a plurality of circular light trap are followed the circumference of diaphragm body is arranged.
3. The optical detection system of claim 1, wherein: the light changing module is also provided with a bearing disc and a circular perforation arranged on the bearing disc, the light shielding plate is positioned at the center of the circular perforation and fixed on the bearing disc, and the diameter of the light shielding plate is smaller than the size of the circular perforation so as to form an annular gap between the light shielding plate and the bearing disc.
4. The optical detection system of claim 3, wherein: the shading plate is provided with a plurality of shading plates with different sizes, a plurality of circular through holes with different sizes are arranged on the bearing plate, and the shading plates which are matched with each other are arranged in each circular through hole.
5. The optical detection system of claim 1, wherein: the imaging unit is provided with a relay system between the optical filter and the objective lens, the relay system comprises a first convex lens and a second convex lens which are sequentially arranged on a transmission path of an emergent beam, and a focus of the first convex lens coincides with a focus position of the second convex lens.
6. An optical inspection apparatus, comprising: the method comprises the following steps: an optical detection system as claimed in any one of claims 1 to 5;
when the light shielding plate is positioned on a transmission path of incident light beams, the incident light beams entering the objective lens are diffracted to form dark field detection light beams;
when the shading plate moves out of the transmission path of the incident beam, the incident beam entering the objective lens forms a bright field detection beam;
the imaging unit is further used for receiving the bright field outgoing beam reflected by the object to be detected and collecting a bright field image of the object to be detected, and the light condensation module is used for focusing the bright field outgoing beam incident from the objective lens on the image collection module when the bright field image is collected;
when a dark field image is collected, the optical filter is arranged between the condenser lens and the objective lens, and the condenser lens is used for focusing diffuse reflection light which is not filtered by the optical filter in dark field emergent light beams on the image collection module.
7. The optical inspection device of claim 6, wherein: the light changing module is provided with a bearing disc, the light shading plate and the bright field light holes are arranged on the bearing disc, and the light shading plate and the bright field light holes are distributed along the circumferential direction of the bearing disc.
8. The optical inspection device of claim 7, wherein: the image acquisition module comprises a bright field image collector for acquiring a bright field image and a dark field image collector for acquiring a dark field image, and the condenser lens comprises a bright field condenser lens arranged on the front side of the bright field image collector and a dark field condenser lens arranged on the front side of the dark field image collector;
when a bright field image is collected, a bright field emergent light beam emitted from the objective lens passes through a bright field condenser lens along a bright field imaging light path to reach a bright field image collector;
when a dark field image is collected, a dark field emergent light beam emitted from the objective lens sequentially passes through the optical filter and the dark field condenser lens along a dark field imaging light path to reach the dark field image collector.
9. The optical inspection device of claim 8, wherein: the imaging unit is also provided with an imaging light splitting module which is simultaneously positioned on a transmission path of the bright field emergent light beam and a transmission path of the dark field emergent light beam;
when a bright field image is collected, the imaging light splitting module is used for transmitting part of the bright field emergent light beam to the bright field image collector; when a dark field image is collected, the imaging light splitting module is used for reflecting part of dark field emergent light beams to the dark field image collector;
or when the bright field image is collected, the imaging light splitting module is used for reflecting part of the bright field emergent light beams to the bright field image collector; and when a dark field image is collected, the imaging light splitting module is used for transmitting part of the dark field emergent light beam to the dark field image collector.
10. The optical inspection device of claim 9, wherein: the bright field image collector and the dark field image collector are arranged in parallel, the imaging unit is also provided with a reflector arranged on the dark field imaging light path, and a dark field emergent light beam emitted from the imaging light splitting module is incident on the reflector towards a direction which is 45 degrees of an oblique angle with the plane where the reflector is located.
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| CN202221055010.1U CN217505680U (en) | 2022-05-06 | 2022-05-06 | Optical detection system and optical detection device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115656210A (en) * | 2022-12-13 | 2023-01-31 | 苏州高视半导体技术有限公司 | Optical detection system, control method thereof, electronic apparatus, and storage medium |
| CN117434737A (en) * | 2023-12-20 | 2024-01-23 | 苏州矽行半导体技术有限公司 | Lighting system and detection equipment |
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2022
- 2022-05-06 CN CN202221055010.1U patent/CN217505680U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115656210A (en) * | 2022-12-13 | 2023-01-31 | 苏州高视半导体技术有限公司 | Optical detection system, control method thereof, electronic apparatus, and storage medium |
| CN117434737A (en) * | 2023-12-20 | 2024-01-23 | 苏州矽行半导体技术有限公司 | Lighting system and detection equipment |
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