Device and method for simultaneous complete equal-path confocal imaging detection of adjacent surfaces based on parallel plate imaging

Abstract

The present invention application proposes a new method for realizing spatial separation imaging detection of adjacent two surfaces based on the basic structural principle of the adjacent surface complete equal optical path confocal imaging device, using a parallel plate in the adjacent double-surface imaging light path respectively. Like the polarization image separation method, the two-color separation imaging method or the time difference resolution imaging method, the new method can obtain simultaneous complete equal optical path confocal imaging detection of adjacent two surfaces of semiconductor grains, but without the use of polarization optical elements and polarization CMOS sensors (cameras), or color cameras and their additional image processing, which effectively improves the cost performance and detection efficiency of the detection device.

Description

Technical field:

[0002] The invention belongs to the field of optical detection and machine vision, and in particular relates to a device and method for detecting simultaneous confocal imaging of adjacent surfaces with completely equal optical path based on parallel flat plate imaging. Background technology:

[0004] In recent years, the combination of optical imaging technology and artificial intelligence has become a very active research field in the application of optical engineering technology. The intelligent manufacturing of semiconductor cooling device grains is inseparable from machine vision automatic optical detection technology. In order to improve production efficiency, the traditional machine vision optical automatic detection device based on an imaging device to detect one surface of the object to be tested can no longer meet the ever-evolving detection application needs. The research on simultaneous defect imaging detection technology on both sides of semiconductor grains has become very necessary, and the complete equal-optical confocal imaging of the double-sided imaging detection light path is one of the main core technical problems that need to be solved.

[0005] The main optical technical problems that need to be solved by the device and method for simultaneous defect detection on opposite or adjacent surfaces of semiconductor grains include equal optical path confocal imaging of the double-sided detection light path. The existing authorized patents and patent applications all use a large-field telecentric imaging lens to solve the confocal and resolution problems caused by the optical path difference between the double-sided imaging light paths. The patent application (application number 2019113692573, 2020101330447, not published) solves the detection device and method for simultaneous equal optical path confocal imaging and equal illumination illumination of the opposite surfaces of grains, such as Figure 1 , as shown in 2.

[0006] and Figure 3 The optical detection device and method proposed in application No. 202010171706X (unpublished) solve the problem of quasi-equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains. However, there is still an optical path difference △ between the adjacent double-sided imaging light paths. This small optical path difference △ can be compensated by selecting a telecentric imaging lens with a sufficiently large depth of field. When the size of the semiconductor grain to be detected increases, the optical path difference △ and the object field of view VOF=△+a also increase accordingly. A telecentric imaging lens with a large field of view and a large depth of field must be used, which will correspondingly increase the cost of the telecentric imaging lens.

[0007] Figure 4 A new method based on time-difference resolved imaging is proposed to achieve complete equal-path confocal imaging detection of adjacent surfaces of semiconductor grains using a single-group imaging system.

[0008] Figure 5The patent application uses a polarization beam splitter to obtain two illumination beams with mutually perpendicular polarization directions, respectively illuminating the adjacent two sides of the semiconductor grain to be tested, and proposes a method based on polarization light separation imaging (abbreviated as "polarization imaging"), using a polarization camera to realize a device and method for simultaneous and completely equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains.

[0009] Figure 6 The patent application proposes a new method that is still based on the principle of polarized light separation imaging (abbreviated as "polarization separation"), combined with a "polarization separation prism assembly" and uses an ordinary CMOS or CCD camera to achieve simultaneous and completely equal-optical-path confocal imaging detection of adjacent surfaces of semiconductor grains. Summary of the invention:

[0011] The present invention application proposes a new method based on a completely equal-optical-path confocal imaging device for adjacent surfaces. Like the polarization image separation method, the two-color separation imaging method or the time-difference resolution imaging method, the new method can obtain simultaneous completely equal-optical-path confocal imaging detection of two adjacent surfaces of semiconductor grains, but does not require the use of polarization optical elements and polarization CMOS sensors (cameras), or color cameras and their additional image processing, effectively improving the cost-effectiveness and detection efficiency of the detection device.

[0012] The invention discloses a confocal imaging detection device for adjacent surfaces simultaneously with completely equal optical path based on parallel flat plate image splitting, which is characterized by comprising: a CMOS or CCD camera, a telecentric imaging lens, a cubic beam splitter and image combiner, a semiconductor crystal grain and a transparent glass stage for holding the semiconductor crystal grain, which are sequentially arranged in the direction of the optical path; a sky right-angle image rotation prism, a first glass parallel flat plate, a side right-angle image rotation prism and a second glass parallel flat plate are sequentially arranged in the optical path between the semiconductor crystal grain and the cubic beam splitter and image combiner; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located at the front side of the semiconductor crystal grain and directly above the sky; the cubic beam splitter and image combiner are at the same horizontal height as the first glass parallel flat plate and the sky right-angle image rotation prism; the side right-angle image rotation prism, the second glass parallel flat plate and the cubic beam splitter and image combiner are located on the optical axis of the telecentric imaging lens; and the side right-angle image rotation prism and the second glass parallel flat plate are simultaneously arranged on the optical path between the semiconductor crystal grain and the cubic beam splitter and image combiner. The first right-angled surface of the angle-turning prism is opposite to the first surface of the cubic beam splitter and combiner, the second right-angled surface of the side right-angled image-turning prism is opposite to the side surface of the semiconductor crystal grain, and the inclined surface of the side right-angled image-turning prism is arranged obliquely to the optical axis of the telecentric imaging lens; the two right-angled surfaces of the sky right-angled image-turning prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the cubic beam splitter and combiner; the surface normal of the first glass parallel plate forms an angle with the optical axis of its optical path, and the surface normal of the second glass parallel plate forms an angle with the optical axis of its optical path; a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the cubic beam splitter and combiner, and the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the camera sensor surface with complete equal optical path confocal imaging through the right-angle-turning prism, the glass parallel plate and the cubic beam splitter and combiner, so as to obtain independent images of both sides of the semiconductor crystal grain on a CMOS or CCD camera.

[0013] Furthermore, the distance between the center of the above-mentioned cubic beam splitter and the center of the oblique surface of the side right-angle image rotation prism is D / 2+d, the cubic beam splitter and the oblique surface of the sky right-angle image rotation prism are at the same horizontal height, the distance between the two is D / 2+d, the side imaging light path working distance WD=D / 2+d / 2, the sky imaging light path working distance WD= WD=D / 2+d / 2, D is the width of the transparent glass stage, and d is the length of the right-angle side of the prism; the semiconductor grain sky imaging light path working distance WD=D / 2+d / 2=30mm, and the side imaging light path working distance WD=D / 2+d / 2=30mm.

[0014] Furthermore, the thickness of the first and second glass parallel plates is t=5.83 mm, the angle between the normal line of the glass parallel plate surface and the optical axis is α=25°, the plate glass material is K9, and the calculated interval of the double-sided image is δ=1.8 mm;

[0015] Furthermore, the size of the above-mentioned right-angle image-turning prism on the top is 15*15*15mm, the size of the right-angle image-turning prism on the side is 15*15*15mm, and the size of the cubic beam splitter and combiner is 15*15*15mm; the center of the reflecting surface of the two right-angle image-turning prisms is connected to the center of the semiconductor grain to form a square symmetrical optical path structure with a size of 37.5x 37.5mm.

[0016] Furthermore, the above-mentioned coaxial external illumination light source is monochromatic light, or a quasi-monochromatic light source or white light with a certain spectral bandwidth.

[0017] The invention discloses a method for detecting confocal imaging of adjacent surfaces simultaneously and completely equal optical path based on parallel flat plate imaging, which is characterized in that: the confocal imaging detection device for adjacent surfaces simultaneously and completely equal optical path based on parallel flat plate imaging comprises a CMOS or CCD camera, a telecentric imaging lens, a cubic beam splitter and image combiner, a semiconductor crystal grain and a transparent glass stage for holding the semiconductor crystal grain, which are sequentially arranged in the direction of the optical path; a sky right-angle image rotation prism, a first glass parallel flat plate, a side right-angle image rotation prism and a second glass parallel flat plate are sequentially arranged in the optical path between the semiconductor crystal grain and the cubic beam splitter and image combiner; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located on the front side of the semiconductor crystal grain and directly above the sky; the cubic beam splitter and image combiner are at the same horizontal height as the first glass parallel flat plate and the sky right-angle image rotation prism; the side right-angle image rotation prism, the second glass parallel flat plate and the cubic beam splitter and image combiner are located at the telecentric imaging On the optical axis of the lens, the first right-angle surface of the side right-angle image-turning prism is opposite to the first surface of the cubic beam splitter and image combiner, the second right-angle surface of the side right-angle image-turning prism is opposite to the side surface of the semiconductor crystal grain, and the inclined surface of the side right-angle image-turning prism is inclined to the optical axis of the telecentric imaging lens; the two right-angle surfaces of the sky right-angle image-turning prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the cubic beam splitter and image combiner; the normal line of the surface of the first glass parallel plate forms an angle with the optical axis of its optical path, and the normal line of the surface of the second glass parallel plate forms an angle with the optical axis of its optical path, and a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the cubic beam splitter and image combiner, and the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the camera sensor surface with complete equal optical path confocal imaging through the right-angle image-turning prism, the glass parallel plate, and the cubic beam splitter and image combiner, so as to obtain independent images of both sides of the semiconductor crystal grain on the CMOS or CCD camera; when working,

[0018] Double-sided lighting light path:

[0019] The coaxial external illumination light source is divided into two illumination light beams when passing through the cubic beam splitter and image combiner: one light beam passes through the top right-angle image rotation prism and the first glass parallel plate to illuminate the top surface of the semiconductor crystal grain to be tested on the glass object carrier turntable; and the other illumination light beam passes through the side right-angle image rotation prism and the second glass parallel plate to illuminate the side surface of the semiconductor crystal grain to be tested, and the two illumination light beams illuminate two adjacent surfaces of the semiconductor crystal grain respectively;

[0020] Imaging detection optical path:

[0021] The two adjacent surfaces of the illuminated semiconductor crystal grains produce diffuse light. The imaging light beam of the semiconductor crystal grains on the sky surface is incident on the first glass parallel plate with a thickness of t and a surface normal at an angle α to the optical axis through the sky surface right-angle image rotation prism. The imaging light beam emitted from the first glass parallel plate has a displacement δ to one side of the optical axis. 1 , and then reflected by the cubic beam splitter and combiner to reach the reference output surface; the imaging beam on the side of the semiconductor grain is incident on the second glass parallel plate with a thickness of t and a surface normal that forms an angle α with the optical axis through the side right-angle image-reversing prism. The imaging beam emitted from the second glass parallel plate also produces a displacement δ to the other side of the optical axis 2 , and then transmitted through the cubic beam splitter and combiner to reach the reference output surface; the interval between the intermediate images of adjacent surfaces output from the cubic beam splitter and combiner is δ=δ 1 +δ 2 And independent images of both sides are obtained on CMOS or CCD camera.

[0022] Advantages of the device and method of the present invention:

[0023] 1) The device can realize the confocal imaging detection of the adjacent two sides of semiconductor grains with completely equal optical path, that is, △=0, without the need to use a telecentric lens with a large field of view to compensate for the optical path difference of the adjacent two-side imaging;

[0024] 2) The use of glass parallel plates in the imaging optical path of the device can obtain the expected spatial separation δ of double-sided imaging, and the double image interval δ can be adjusted. For a given glass parallel plate thickness t and glass refractive index n, the size of the interval δ depends on the angle α formed by the surface normal of the glass parallel plate and the optical axis;

[0025] 3) The device can also use the glass parallel plate to fine-tune the angles in the meridian and sagittal planes to correct and compensate for the deviation of the relative spatial position of the double-sided imaging caused by the manufacturing error of the cubic prism or the right-angle image-transfer prism and its assembly error;

[0026] 4) This device uses an ordinary glass parallel plate and a CMOS or CCD camera, and does not require the use of polarization optical elements and polarization CMOS sensors (cameras), or color cameras and their additional image processing, which can effectively reduce the cost of the detection device and improve the cost performance and detection efficiency of the detection device.

[0027] 5) The semiconductor grain adjacent double-sided simultaneous imaging detection device has a simple and compact structure, is easy to assemble and debug, and has good reliability. Description of the drawings:

[0029] Figure 1-6It is an existing optical device for detecting adjacent surfaces of semiconductor grains;

[0030] 1 is a black and white camera, 2 is a telecentric imaging lens, 3a or 3b is an image transfer prism, 3 is an image combining optical element, 4 is a semiconductor crystal, 5 is a transparent glass stage, 6 or 6a or 6b is an image transfer prism, 7 or 7a and 7b are light sources, and 8 and 9 are filters;

[0031] Figure 7 It is a schematic diagram of the principle of the device of the present invention;

[0032] Figure 8a It is a schematic diagram of the adjustment of the glass parallel plate in the meridian plane;

[0033] Figure 8b It is a schematic diagram of the adjustment of the glass parallel plate in the sagittal plane;

[0034] Fig. 9 It is a schematic diagram of an embodiment of the device of the present invention with corresponding dimensions. Specific implementation method:

[0036] The present invention discloses a confocal imaging detection device for adjacent surfaces simultaneously with completely equal optical path based on parallel plate image splitting, comprising a CMOS or CCD camera 1, a telecentric imaging lens 2, a cubic beam splitter and image combiner 3, a semiconductor crystal grain 6 and a transparent glass stage 7 for holding the semiconductor crystal grain, which are sequentially arranged in the optical path direction; a sky right-angle image rotation prism 4a, a first glass parallel plate 5a, a side right-angle image rotation prism 4b and a second glass parallel plate 5b are sequentially arranged in the optical path between the semiconductor crystal grain 6 and the cubic beam splitter and image combiner 3; the side right-angle image rotation prism 4b and the sky right-angle image rotation prism 4a are respectively located on the front side of the semiconductor crystal grain and directly above the sky; the cubic beam splitter and image combiner 3 and the first glass parallel plate 5a and the sky right-angle image rotation prism 4a are at the same horizontal height; the side right-angle image rotation prism 4b and the second glass parallel plate 5b and the cubic beam splitter and image combiner 3 are located on the optical axis A of the telecentric imaging lens; and at the same time, the first right-angle surface 401b of the side right-angle image rotation prism and the second glass parallel plate 5b are arranged on the optical axis A of the telecentric imaging lens; and The first surface 301 of the cubic beam splitter and combiner 3 is opposite, the second right-angle surface 402b of the side right-angle image-reversing prism is opposite to the side surface of the semiconductor crystal grain, and the inclined surface 403b of the side right-angle image-reversing prism is inclined to the optical axis A of the telecentric imaging lens; the two right-angle surfaces 401a and 402a of the sky right-angle image-reversing prism are opposite to the sky surface of the semiconductor crystal grain and the second surface 302 of the cubic beam splitter and combiner respectively; the surface normal of the first glass parallel plate 5a forms an angle α with the optical axis B of its optical path, The surface normal of the second glass parallel plate 5b forms an angle α with the optical axis A of its optical path. A coaxial external illumination light source 8 is provided on the side of the fourth surface 304 opposite to the second surface 302 of the cubic beam splitter and combiner. The top surface and the side surface of the semiconductor crystal grain are respectively imaged on the camera sensor surface with complete equal optical path confocal imaging via right-angle image rotation prisms 4a, 4b, glass parallel plates 5a, 5b, and cubic beam splitter and combiner 3, so as to obtain independent images of both sides of the semiconductor crystal grain on the CMOS or CCD camera.

[0037] The first and second glass parallel plates 5a and 5b in the zenith and side imaging optical paths of the present application are used to cause the double-sided imaging beams to generate a displacement δ to both sides of the center (optical axis) of the cubic beam splitter and combiner 3. 1 and δ 2 And δ 1 With δ 2 The size of depends on the thickness t of the parallel plate, the refractive index n of the glass, and the angle α between the normal line of the parallel plate surface and the optical axis. x .

[0038] The images of adjacent surfaces of semiconductor grains output from the image combiner 3 are separated in space, and the image interval is δ=δ 1 +δ 2 .

[0039] The deviation of the relative spatial position of the double-sided imaging due to the angular error and assembly error of the cubic prism or the right-angle image-reversing prism can be corrected by fine-tuning the angle α between the normal line of the parallel plate surface and the optical axis in the meridian plane (yz plane, the z axis is along the optical axis direction). x ±ε to correct the compensation, such as Figure 8a Similarly, the angle α between the normal line of the parallel plate surface and the optical axis can be fine-tuned in the sagittal plane (xz plane). y ±ε to correct the compensation, such as Figure 8b shown.

[0040] The distance between the center of the above-mentioned cubic beam splitter and combiner 3 and the center of the inclined surface of the side right-angle image rotation prism 4b is D / 2+d, the cubic beam splitter and combiner 3 and the inclined surface of the sky right-angle image rotation prism 4a are at the same horizontal height, the distance between the two is D / 2+d, the side imaging light path working distance WD=D / 2+d / 2, the sky imaging light path working distance WD= WD=D / 2+d / 2, D is the width of the transparent glass stage, and d is the length of the right-angle side of the prism; the semiconductor grain sky imaging light path working distance WD=D / 2+d / 2=30mm, and the side imaging light path working distance WD=D / 2+d / 2=30mm.

[0041] The specific implementation is as follows Fig. 9 As shown, the thickness of the first and second glass parallel plates is t=5.83 mm, the angle between the normal line of the glass parallel plate surface and the optical axis is α=25°, the plate glass material is K9, and the calculated interval of the double-sided image is δ=1.8 mm.

[0042] The size of the top right-angle image-turning prism is 15*15*15mm, the size of the side right-angle image-turning prism is 15*15*15mm, and the size of the cubic beam splitter and combiner is 15*15*15mm; the center of the reflecting surface of the two right-angle image-turning prisms is connected to the center of the semiconductor grain to form a square symmetrical optical path structure with a size of 37.5x 37.5mm.

[0043] The above-mentioned coaxial external illumination light source is monochromatic light, or may also be a quasi-monochromatic light source or white light with a certain spectral bandwidth.

[0044] A cubic beam splitter and image combiner is a cubic beam splitter prism composed of two identical right-angle prisms. It functions as a beam splitter in the illumination light path and as an image combiner in the imaging light path. Its shape is cubic, hence the name. A beam splitter film with a transmission and reflection ratio of 50%:50% is plated on the inclined surface of a right-angle prism, and the inclined surfaces of two right-angle reflecting prisms are glued together.

[0045] The invention discloses a method for detecting confocal imaging of adjacent surfaces simultaneously and completely equal optical path based on parallel flat plate imaging. The confocal imaging detection device for adjacent surfaces simultaneously and completely equal optical path based on parallel flat plate imaging comprises a CMOS or CCD camera, a telecentric imaging lens, a cubic beam splitter and image combiner, a semiconductor crystal grain and a transparent glass stage for holding the semiconductor crystal grain, which are sequentially arranged in the direction of the optical path. A sky right-angle image rotation prism, a first glass parallel flat plate, a side right-angle image rotation prism and a second glass parallel flat plate are sequentially arranged in the optical path between the semiconductor crystal grain and the cubic beam splitter and image combiner. The side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located at the front side of the semiconductor crystal grain and directly above the sky. The cubic beam splitter and image combiner are at the same horizontal height as the first glass parallel flat plate and the sky right-angle image rotation prism. The side right-angle image rotation prism, the second glass parallel flat plate and the cubic beam splitter and image combiner are located at the same horizontal height as the first glass parallel flat plate and the sky right-angle image rotation prism. On the optical axis of the imaging lens, the first right-angle surface of the side right-angle image-turning prism is opposite to the first surface of the cubic beam splitter and combiner, the second right-angle surface of the side right-angle image-turning prism is opposite to the side surface of the semiconductor crystal grain, and the inclined surface of the side right-angle image-turning prism is inclined to the optical axis of the telecentric imaging lens; the two right-angle surfaces of the sky right-angle image-turning prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the cubic beam splitter and combiner; the normal line of the surface of the first glass parallel flat plate forms an angle with the optical axis of its optical path, and the normal line of the surface of the second glass parallel flat plate forms an angle with the optical axis of its optical path, and a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the cubic beam splitter and combiner, and the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the camera sensor surface with complete equal optical path confocal imaging through the right-angle image-turning prism and the cubic beam splitter and combiner, so as to obtain independent images of both sides of the semiconductor crystal grain on the CMOS or CCD camera; when working,

[0046] Double-sided lighting light path:

[0047] The coaxial external illumination light source is divided into two illumination light beams when passing through the cubic beam splitter and image combiner: one light beam passes through the top right-angle image rotation prism and the first glass parallel plate to illuminate the top surface of the semiconductor crystal grain to be tested on the glass object carrier turntable; and the other illumination light beam passes through the side right-angle image rotation prism and the second glass parallel plate to illuminate the side surface of the semiconductor crystal grain to be tested, and the two illumination light beams illuminate two adjacent surfaces of the semiconductor crystal grain respectively;

[0048] Imaging detection optical path:

[0049] The two adjacent surfaces of the illuminated semiconductor crystal grains produce diffuse light. The imaging light beam of the semiconductor crystal grains on the sky surface is incident on the first glass parallel plate with a thickness of t and a surface normal at an angle α to the optical axis through the sky surface right-angle image rotation prism. The imaging light beam emitted from the first glass parallel plate has a displacement δ to one side of the optical axis. 1, and then reflected by the cubic beam splitter and combiner to reach the reference output surface; the imaging beam on the side of the semiconductor grain is incident on the second glass parallel plate with a thickness of t and a surface normal that forms an angle α with the optical axis through the side right-angle image-reversing prism. The imaging beam emitted from the second glass parallel plate also produces a displacement δ to the other side of the optical axis 2 , and then transmitted through the cubic beam splitter and combiner to reach the reference output surface; the interval between the intermediate images of adjacent surfaces output from the cubic beam splitter and combiner is δ=δ 1 +δ 2 And independent images of both sides are obtained on CMOS or CCD camera.

[0050] Advantages of the device and method of the present invention:

[0051] 1) The device can realize the confocal imaging detection of the adjacent two sides of semiconductor grains with completely equal optical path, that is, △=0, without the need to use a telecentric lens with a large field of view to compensate for the optical path difference of the adjacent two-side imaging;

[0052] 2) The use of glass parallel plates in the imaging optical path of the device can obtain the expected spatial separation δ of double-sided imaging, and the double image interval δ can be adjusted. For a given glass parallel plate thickness t and glass refractive index n, the size of the interval δ depends on the angle α formed by the surface normal of the glass parallel plate and the optical axis;

[0053] 3) The device can also use the glass parallel plate to fine-tune the angles in the meridian and sagittal planes to correct and compensate for the deviation of the relative spatial position of the double-sided imaging caused by the manufacturing error of the cubic prism or the right-angle image-transfer prism and its assembly error;

[0054] 4) This device uses an ordinary glass parallel plate and a CMOS or CCD camera, and does not require the use of polarization optical elements and polarization CMOS sensors (cameras), or color cameras and their additional image processing, which can effectively reduce the cost of the detection device and improve the cost performance and detection efficiency of the detection device.

[0055] 5) The semiconductor grain adjacent double-sided simultaneous imaging detection device has a simple and compact structure, is easy to assemble and debug, and has good reliability.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A confocal imaging detection device for adjacent surfaces simultaneously with completely equal optical path lengths based on parallel plate imaging. Features: The invention comprises a CMOS or CCD camera, a telecentric imaging lens, a cubic beam splitter and image combiner, a semiconductor crystal grain and a transparent glass stage for holding the semiconductor crystal grain, which are sequentially arranged in the optical path direction; a sky right-angle image rotation prism, a first glass parallel plate, a side right-angle image rotation prism and a second glass parallel plate are sequentially arranged in the optical path between the semiconductor crystal grain and the cubic beam splitter and image combiner; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located at the positive side of the semiconductor crystal grain and directly above the sky surface; the cubic beam splitter and image combiner are at the same horizontal height as the first glass parallel plate and the sky right-angle image rotation prism; the side right-angle image rotation prism, the second glass parallel plate and the cubic beam splitter and image combiner are located on the optical axis of the telecentric imaging lens; at the same time, the first right-angle surface of the side right-angle image rotation prism is opposite to the first surface of the cubic beam splitter and image combiner, the second right-angle surface of the side right-angle image rotation prism is opposite to the side surface of the semiconductor crystal grain, and the inclined surface of the side right-angle image rotation prism is opposite to the telecentric imaging lens. The optical axis is tilted; the two right-angled surfaces of the sky right-angle image prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the cubic beam splitter and combiner; the normal line of the surface of the first glass parallel flat plate forms an angle with the optical axis of its optical path, and the normal line of the surface of the second glass parallel flat plate forms an angle with the optical axis of its optical path; a coaxial external illumination light source is arranged on the side of the fourth surface opposite to the second surface of the cubic beam splitter and combiner; the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the camera sensor surface with complete equal optical path confocal imaging through the right-angle image prism, the glass parallel flat plate, and the cubic beam splitter and combiner, so as to obtain independent images of the two sides of the semiconductor crystal grain on the CMOS or CCD camera; the distance between the center of the cubic beam splitter and combiner and the center of the inclined surface of the side right-angle image prism is D / 2+d, the cubic beam splitter and combiner and the inclined surface of the sky right-angle image prism are at the same horizontal height, the distance between the two is D / 2+d, the side imaging optical path working distance WD=D / 2+d / 2, the sky imaging optical path working distance WD= WD=D / 2+d / 2, D is the width of the transparent glass stage, d is the length of the right angle side of the prism; The working distance of the semiconductor crystal grain imaging light path on the sky is WD=D / 2+d / 2=30mm, and the working distance of the side imaging light path is WD=D / 2+d / 2=30mm; the thickness of the first and second glass parallel plates is t=5.83mm, the angle α between the surface normal of the glass parallel plate and the optical axis is 25°, the plate glass material is K9, and the calculated interval of the double-sided image is δ=1.8mm; the size of the sky right-angle image rotation prism is 15*15*15mm, the size of the side right-angle image rotation prism is 15*15*15mm, and the size of the cubic beam splitter and combiner is 15*15*15mm; the center of the reflection surface of the two right-angle image rotation prisms is connected to the center of the semiconductor crystal grain to form a square symmetrical light path structure with a size of 37.5x37.5mm; the coaxial external illumination light source is monochromatic light, or a quasi-monochromatic light source with a certain spectral bandwidth or white light; when working, Double-sided lighting light path: The coaxial external illumination light source is divided into two illumination light beams when passing through the cubic beam splitter and image combiner: one light beam passes through the top right-angle image rotation prism and the first glass parallel plate to illuminate the top surface of the semiconductor crystal grain to be tested on the glass object carrier turntable; and the other illumination light beam passes through the side right-angle image rotation prism and the second glass parallel plate to illuminate the side surface of the semiconductor crystal grain to be tested, and the two illumination light beams illuminate two adjacent surfaces of the semiconductor crystal grain respectively; Imaging detection optical path: The two adjacent faces of the illuminated semiconductor crystal grain produce diffuse light. The imaging light beam of the top face of the semiconductor crystal grain is incident on a first glass parallel plate with a thickness of t and a surface normal that forms an angle α with the optical axis through a top face right-angle image-reversing prism. The imaging light beam emitted from the first glass parallel plate produces a displacement δ1 to one side of the optical axis, and then is reflected by a cubic beam splitter and image combiner to reach a reference output face; while the imaging light beam of the side face of the semiconductor crystal grain is incident on a second glass parallel plate with a thickness of t and a surface normal that forms an angle α with the optical axis through a side right-angle image-reversing prism. The imaging light beam emitted from the second glass parallel plate also produces a displacement δ2 to the other side of the optical axis, and then is transmitted by a cubic beam splitter and image combiner to reach a reference output face; the intermediate images of adjacent faces output from the cubic beam splitter and image combiner are separated by δ=δ1+δ2, and independent images of both faces are obtained on a CMOS or CCD camera.

Images