Device and method for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method

Abstract

The present invention discloses a device and method for realizing simultaneous equal optical path confocal detection of both sides of a crystal grain by using a polarization image splitting method. The device comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, a right-angle image rotation prism, 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. The device and method of the present invention have the following advantages: although the double images of adjacent sides of the semiconductor crystal grain are spatially separated on the polarization image splitting prism assembly, the polarization imaging of both sides of the semiconductor crystal grain satisfies complete equal optical path, i.e., △=0, or quasi-equal optical path △≈0.

Description

Technical field:

[0001] The invention belongs to the field of optical detection and machine vision, and in particular relates to a device and a method for realizing simultaneous equal-optical-path confocal detection of both sides of a grain by using a polarization image splitting method. Background technology:

[0002] The main optical technical problem that needs to be solved by the device and method for simultaneous defect detection on opposite or adjacent surfaces of semiconductor grains is equal optical path confocal imaging of the double-sided detection light path.

[0003] Patent applications (application numbers 2019113692573, 2020101330447, not published, e.g. Figure 1 , 2 The invention solves the problem of simultaneous equal-path confocal imaging and equal-illuminance illumination detection of opposite surfaces of semiconductor grains.

[0004] Figure 3 The optical detection device and method proposed in application No. 202010171706X (unpublished) solve the problem of quasi-equal-path confocal imaging detection of adjacent surfaces of semiconductor grains.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 increase the cost of the telecentric imaging lens accordingly. Therefore, it becomes necessary to find a new way to perform confocal imaging detection of adjacent surfaces of grains with completely equal-path.

[0005] Figure 4 In order to effectively utilize the energy of the illumination light source and improve the illumination efficiency, a polarization beam splitter is used to obtain two illumination light beams with mutually perpendicular polarization directions, which respectively illuminate the adjacent two sides of the semiconductor grain to be tested. However, this method requires the use of a polarization camera, which has a high manufacturing cost. Summary of the invention:

[0006] In response to the above-mentioned problems existing in adjacent surface detection, the present invention application proposes a device and method for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting. The device does not need to use an expensive polarization camera. The cost of an ordinary CMOS or CCD camera is currently about 10% of that of a polarization camera. Even if the cost of the polarization image splitting prism assembly is increased, the cost of the detection system can be effectively reduced.

[0007] The present invention uses a polarization image splitting method to realize a device for simultaneous equal optical path confocal detection of both sides of a crystal grain, and is characterized in that: it comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a top right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the top right-angle image rotation prism are respectively located on the front side of the semiconductor crystal grain and directly above the top surface; the polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; The second right-angle surface of the side right-angle image-turning prism is opposite to the side surface of the semiconductor crystal grain, the inclined surface of the side right-angle image-turning prism is inclined to the optical axis of the telecentric imaging lens, and 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 polarization cube beam splitter; the polarization image splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens side, a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the polarization cube beam splitter, the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera by equal optical path confocal polarization through the right-angle image-turning prism, the polarization cube beam splitter and the polarization image splitting prism assembly, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera.

[0008] The present invention uses a polarization image splitting method to realize a device for simultaneous equal optical path confocal detection of both sides of a crystal grain, which is characterized by comprising: a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a top right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the top right-angle image rotation prism are respectively located on the front side of the semiconductor crystal grain and directly above the top surface; the polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter are located on the optical axis of the telecentric imaging lens; at the same time, a first right-angle surface of the side right-angle image rotation prism is aligned and glued to a first surface of the polarization cube beam splitter; and a second right-angle surface of the side right-angle image rotation prism is aligned and glued to a first surface of the polarization cube beam splitter. The right-angle surface is opposite to the side surface of the semiconductor crystal grain, the inclined surface of the side right-angle image-turning prism is inclined to the optical axis of the telecentric imaging lens, and the two right-angle surfaces of the sky-plane right-angle image-turning prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the polarization cube beam splitter; the polarization image-splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens side, and coaxial external illumination light sources are respectively provided between the side right-angle image-turning prism and the side surface of the semiconductor crystal grain, and between the sky-plane right-angle image-turning prism and the sky surface of the semiconductor crystal grain, and the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera through the right-angle image-turning prism, the polarization cube beam splitter, and the polarization image-splitting prism assembly with equal optical path and confocal polarization, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera.

[0009] Furthermore, the polarization imaging illumination light path: the illumination light source is divided into two beams of linear polarized light with mutually perpendicular polarization directions when passing through the polarization cube beam splitter, namely the p-component and the s-component; one beam of p-component polarized light passes through the top right-angle image-turning prism to illuminate the top surface of the semiconductor crystal grain to be measured; and the other beam of s-component polarized light passes through the side right-angle image-turning prism to illuminate the side surface of the semiconductor crystal grain to be measured, and the two beams of linear polarized light with mutually perpendicular vibration directions respectively illuminate the two adjacent surfaces of the semiconductor crystal grain.

[0010] Furthermore, two beams of linearly polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to generate diffuse reflected light; the s-component of the imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly, and the double-sided image output from the polarization image-splitting prism assembly obtains independent images of both sides on an ordinary CMOS or CCD camera.

[0011] Furthermore, the working distance WD of the above-mentioned celestial imaging light path is d / 2, where d is the length of the right-angle side of the prism; the polarization cube beam splitter is glued to the side right-angle image rotation prism and their centers coincide, and the working distance WD of the side imaging light path is D / 2+d / 2, where D is the width of the transparent glass stage; the coaxial external illumination light source is monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

[0012] Furthermore, the size of the above-mentioned right-angle image-transmitting prism on the top surface is 15*15*15mm, the size of the right-angle image-transmitting prism on the side surface is 15*15*15mm, the size of the polarization cube beam splitter is 15*15*15mm, the size of the Wollaston polarizing prism is 10mm long, 10mm wide, and 11mm high, and the size of the roof prism is 10mm long, 10mm wide, and 3.17mm high.

[0013] Furthermore, the images formed by the polarized light output from the polarization splitting prism assembly to the adjacent surfaces of the semiconductor crystal grains are separated in space; using a common CMOS or CCD camera, equal-path confocal imaging detection in which the polarization of the top and side light paths of the semiconductor crystal grains can be separated respectively is obtained; or using a common CMOS or CCD camera, complete equal-path confocal polarization imaging detection in which the polarization directions of the top and side imaging light paths can be separated at 0 degrees and 90 degrees is obtained respectively.

[0014] Furthermore, the above assumption is that the size of the Wollaston polarizing prism made of calcite is L 1 ×W 1 ×H 1 =10×10×11, the prism vertex angle is θ=45°, and the refractive indices of o-light and e-light are n o =1.658 and n e =1.486; the size of the roof prism made of K9 material is L 2 ×W 2 ×H 2 =10×10×3.17, the angles between the left and right ridges and the horizontal direction are ε 1 and ε 2 , the refractive index is n k9 =1.5163; the air gap height between the Wollaston polarizing prism and the roof prism is H 3 The refractive index of air is n air =1.0; Assume that the side imaging beam (p-component) is incident vertically on the first prism of the Wollaston polarizing prism as e-light, is converted into o-light at the second prism of the Wollaston polarizing prism, is shifted to the left and is finally imaged on the left side of the camera; the sky imaging beam (s-component) is incident vertically on the first prism of the Wollaston polarizing prism as o-light, is converted into e-light at the second prism of the Wollaston polarizing prism, is shifted to the right and is finally imaged on the right side of the camera;

[0015] Assume that the refraction angle of the side light path from the first prism of the Wollaston polarizing prism to the second prism is α 1 The refraction angle from the Wollaston polarizing prism to the air gap is β 1 , the refraction angle of the incident light from the air gap to the roof prism is γ 1 Then we have:

[0016]

[0017]

[0018]

[0019]

[0020] For the skylight path, assume that the refraction angle from the first prism of the Wollaston polarizing prism to the second prism is α 2 The refraction angle from the Wollaston polarizing prism to the air gap is β 2 , the refraction angle of the roof prism incident from the air gap is γ 2 Then we have:

[0021]

[0022]

[0023]

[0024]

[0025] Assume that the optical paths of the side light path through the Wollaston polarizing prism, the air gap, the roof prism, and the vertical emission to the same horizontal height as the vertex of the roof prism are L 11 , L 12 , L 13 and L 14 The resulting offsets are δ 11 , δ 12 and δ 13 ; The total optical path is L 1 , the total offset is δ 1 , then:

[0026] δ 1 =δ 11 +δ 12 +δ 13

[0027] L 1 =L 11 +L 12 +L 13 +L 14

[0028]

[0029] δ 12 =H 3 *tan(β 1 )

[0030] Depend on Can be obtained:

[0031]

[0032]

[0033]

[0034] L 14 =δ 1 *tan(ε 1 )*n air

[0035] For the skylight path, assume that the optical path through the Wollaston polarizing prism, the air gap, the roof-shaped glass wedge, and the vertical emission to the same horizontal height as the vertex of the roof-shaped prism are L 21 , L 22 , L 23 and L 24 The resulting offsets are δ 21 , δ 22 and δ 23 ; The total optical path is L 2 , the total offset is δ 2 , then:

[0036] δ 2 =δ 21 +δ 22 +δ 23

[0037] L 2 =L 21 +L 22 +L 23 +L 24

[0038]

[0039] δ 22 =H 3 *tan(β 2 )

[0040] Depend on Can be obtained:

[0041]

[0042]

[0043]

[0044]

[0045] L 24 =δ 2 *tan(ε 2 )*n air .

[0046] Furthermore, when the Wollaston polarizing prism and the roof-shaped glass wedge are glued together, H 3 =0.00mm, we can get: δ 1 =0.86mm, L 1 =22.03mm,δ 2 =1.02mm, L 2 =22.00mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =1.88mm;

[0047] When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =0.50mm, we can get:δ 1 =0.94mm, L 1 =22.52mm,δ 2 =1.11mm, L 2 =22.49mm; At this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =2.05mm;

[0048] When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =1.50mm, we can get:δ 1 =1.10mm, L 1 =23.51mm,δ 2 =1.29mm, L 2 =23.48mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2=2.39mm.

[0049] The present invention uses polarization image splitting method to realize simultaneous equal optical path confocal detection method of double sides of crystal grains, which is characterized in that: the detection device comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a top right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the top right-angle image rotation prism are respectively located on the front side of the semiconductor crystal grain and directly above the top surface; the polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; the second right-angle surface of the side right-angle image rotation prism is opposite to the side surface of the semiconductor crystal grain; The inclined surface of the side right-angle image-turning prism is arranged obliquely with respect to the optical axis of the telecentric imaging lens, and the two right-angle surfaces of the sky-plane right-angle image-turning prism are respectively opposite to the sky-plane of the semiconductor crystal grain and the second surface of the polarization cube beam splitter; the polarization image-splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens; a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the polarization cube beam splitter, or a coaxial external illumination light source is arranged between the side right-angle image-turning prism and the side surface of the semiconductor crystal grain, and between the sky-plane right-angle image-turning prism and the sky-plane of the semiconductor crystal grain, respectively; the sky-plane and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera through the right-angle image-turning prism, the polarization cube beam splitter, and the polarization image-splitting prism assembly with equal optical path and confocal polarization, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera;

[0050] Polarization imaging illumination light path: When the illumination light source passes through the polarization cube beam splitter, it is divided into two beams of linear polarized light with mutually perpendicular polarization directions, namely the p-component and the s-component; one beam of p-component polarized light passes through the top right-angle image-turning prism to illuminate the top surface of the semiconductor crystal grain to be measured; and the other beam of s-component polarized light passes through the side right-angle image-turning prism to illuminate the side surface of the semiconductor crystal grain to be measured. The two beams of linear polarized light with mutually perpendicular vibration directions illuminate the two adjacent surfaces of the semiconductor crystal grain respectively;

[0051] Polarization imaging optical path:

[0052] Two beams of linear polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to produce diffuse reflected light; the s-component of the imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly. The double-sided image output from the polarization image-splitting prism assembly obtains independent images of both sides on an ordinary CMOS or CCD camera.

[0053] This patent application is based on the method of polarized light separation imaging (abbreviated as "polarization separation"), combined with a "polarization separation prism assembly" and using an ordinary CMOS or CCD camera to achieve another new method for simultaneous and completely equal-optical confocal imaging detection of adjacent surfaces of semiconductor grains. Compared with the existing technology, this new method does not need to use expensive polarization cameras, but can use ordinary CMOS or CCD cameras. The cost of ordinary CMOS or CCD cameras is currently about 10% of that of polarization cameras. Even if the cost of the polarization separation prism assembly is increased, the cost of the detection system can be effectively reduced. Description of the drawings:

[0054] Figure 1-4 It is an existing optical device for detecting adjacent surfaces of semiconductor grains;

[0055] Wherein 1 is a black and white camera, 1a is a polarization 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 or 7b is a light source, and 8 is a controller;

[0056] Figure 5 It is a schematic diagram of the structure of an embodiment of the device of the present invention;

[0057] Figure 6 It is a schematic diagram of the structure of another embodiment of the device of the present invention;

[0058] Figure 7 This is a schematic diagram of the construction of a polarization image splitting prism assembly;

[0059] Figure 8a , 8b 8c is a schematic diagram of an embodiment of a polarization image splitting prism assembly. Specific implementation method:

[0060] Embodiment 1: The present invention uses polarization image splitting method to realize the simultaneous equal optical path confocal detection of both sides of a crystal grain, comprising a CMOS or CCD camera 1, a telecentric imaging lens 2, a polarization image splitting prism assembly 8, a polarization cube beam splitter 3, a semiconductor crystal grain and a transparent glass stage 5 for holding the semiconductor crystal grain, which are arranged in sequence in the direction of the optical path. A side right-angle image rotation prism 6b and a top right-angle image rotation prism 6a are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter. The side right-angle image rotation prism 6b and the top right-angle image rotation prism 6a are respectively located on the front side of the semiconductor crystal grain and directly above the top surface. The polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height. The side right-angle image rotation prism 6b and the polarization cube beam splitter 3 are located on the optical axis of the telecentric imaging lens. At the same time, the first right-angle surface 601 of the side right-angle image rotation prism is aligned and glued with the first surface 301 of the polarization cube beam splitter. The second right-angled surface 602 of the angle-reversing prism is opposite to the side surface 401 of the semiconductor crystal grain, the inclined surface 603 of the side right-angle-reversing prism is inclined to the optical axis of the telecentric imaging lens, and the two right-angled surfaces of the sky right-angle-reversing prism are respectively opposite to the sky surface 402 of the semiconductor crystal grain and the second surface 303 of the polarization cube beam splitter; the polarization image splitting prism assembly 8 includes a Wollaston polarization prism 8a attached to the third surface 303 of the polarization cube beam splitter and a roof prism 8b located on the Wollaston polarization prism near the telecentric imaging lens side, and a coaxial external illumination light source 7 is arranged beside the fourth surface 304 opposite to the second surface of the polarization cube beam splitter. The sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera with equal optical path and confocal polarization through the right-angle-reversing prism, the polarization cube beam splitter, and the polarization image splitting prism assembly, and independent images of the two sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera (such as Figure 5 shown).

[0061] The difference between the second embodiment and the first embodiment is that the coaxial external illumination light source 7 is located between the side right-angle image rotation prism and the side surface of the semiconductor crystal grain, and between the top right-angle image rotation prism and the top surface of the semiconductor crystal grain (such as Figure 6 As shown), the two light sources are 7a and 7b respectively.

[0062] Furthermore, the above-mentioned polarized imaging illumination light path: the illumination light source is divided into two beams of linear polarized light with mutually perpendicular polarization directions when passing through the polarization cube beam splitter, namely the p-component and the s-component; one beam of p-component polarized light illuminates the top surface of the semiconductor crystal grain to be measured through the top right-angle image rotation prism; and the other beam of s-component polarized light illuminates the side surface of the semiconductor crystal grain to be measured through the side right-angle image rotation prism, and the two beams of linear polarized light with mutually perpendicular vibration directions respectively illuminate the two adjacent surfaces of the semiconductor crystal grain.

[0063] Furthermore, the polarization imaging optical path: two beams of linearly polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to generate diffuse reflected light; the s-component imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly, and the double-sided image output from the polarization image-splitting prism assembly obtains two-sided independent images on a common CMOS or CCD camera.

[0064] Furthermore, the working distance WD of the above-mentioned celestial imaging light path is d / 2, where d is the length of the right-angle side of the prism; the polarization cube beam splitter is glued to the side right-angle image rotation prism and their centers coincide, and the working distance WD of the side imaging light path is D / 2+d / 2, where D is the width of the transparent glass stage; the coaxial external illumination light source is monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

[0065] Furthermore, the size of the above-mentioned right-angle image-transmitting prism on the top surface is 15*15*15mm, the size of the right-angle image-transmitting prism on the side surface is 15*15*15mm, the size of the polarization cube beam splitter is 15*15*15mm, the size of the Wollaston polarizing prism is 10mm long, 10mm wide, and 11mm high, and the ridge prism is 10mm long, 10mm wide, and 3.17mm high; the working distances of the top surface and the side light paths (the distance from the right-angle surface of the prism to the center of the grain) are 7.5mm and 30mm respectively.

[0066] Furthermore, the images formed by the polarized light output from the polarization splitting prism assembly to the adjacent surfaces of the semiconductor crystal grains are separated in space; using a common CMOS or CCD camera, equal-path confocal imaging detection in which the polarization of the top and side light paths of the semiconductor crystal grains can be separated respectively is obtained; or using a common CMOS or CCD camera, complete equal-path confocal polarization imaging detection in which the polarization directions of the top and side imaging light paths can be separated at 0 degrees and 90 degrees is obtained respectively.

[0067] Furthermore, the above assumption is that the size of the Wollaston polarizing prism made of calcite is L 1 ×W 1 ×H 1 =10×10×11, the prism vertex angle is θ=45°, and the refractive indices of o-light and e-light are n respectively. o =1.658 and n e =1.486; the size of the roof prism made of K9 material is L 2 ×W 2 ×H 2 =10×10×3.17, the angles between the left and right ridges and the horizontal direction are ε 1 and ε 2 , the refractive index is n k9=1.5163; the air gap height between the Wollaston polarizing prism and the roof prism is H 3 The refractive index of air is n air =1.0; Assume that the side imaging beam (p-component) is incident vertically on the first prism of the Wollaston polarizing prism as e-light, is converted into o-light at the second prism of the Wollaston polarizing prism, is shifted to the left and is finally imaged on the left side of the camera; the sky imaging beam (s-component) is incident vertically on the first prism of the Wollaston polarizing prism as o-light, is converted into e-light at the second prism of the Wollaston polarizing prism, is shifted to the right and is finally imaged on the right side of the camera;

[0068] Assume that the refraction angle of the side light path from the first prism of the Wollaston polarizing prism to the second prism is α 1 The refraction angle from the Wollaston polarizing prism to the air gap is β 1 , the refraction angle of the incident light from the air gap to the roof prism is γ 1 Then we have:

[0069]

[0070]

[0071]

[0072]

[0073] For the skylight path, assume that the refraction angle from the first prism of the Wollaston polarizing prism to the second prism is α 2 The refraction angle from the Wollaston polarizing prism to the air gap is β 2 , the refraction angle of the roof prism incident from the air gap is γ 2 Then we have:

[0074]

[0075]

[0076]

[0077]

[0078] Assume that the optical paths of the side light path through the Wollaston polarizing prism, the air gap, the roof prism, and the vertical emission to the same horizontal height as the vertex of the roof prism are L 11 , L 12 , L 13 and L 14 The resulting offsets are δ 11 , δ 12 and δ 13; The total optical path is L 1 , the total offset is δ 1 , then:

[0079] δ 1 =δ 11 +δ 12 +δ 13

[0080] L 1 =L 11 +L 12 +L 13 +L 14

[0081]

[0082] δ 12 =H 3 *tan(β 1 )

[0083] Depend on Can be obtained:

[0084]

[0085]

[0086]

[0087] L 14 =δ 1 *tan(ε 1 )*n air

[0088] For the skylight path, assume that the optical path through the Wollaston polarizing prism, the air gap, the roof-shaped glass wedge, and the vertical emission to the same horizontal height as the vertex of the roof-shaped prism are L 21 , L 22 , L 23 and L 24 The resulting offsets are δ 21 , δ 22 and δ 23 ; The total optical path is L 2 , the total offset is δ 2 , then:

[0089] δ 2 =δ 21 +δ 22 +δ 23

[0090] L 2 =L 21 +L22 +L 23 +L 24

[0091]

[0092] δ 22 =H 3 *tan(β 2 )

[0093] Depend on Can be obtained:

[0094]

[0095]

[0096]

[0097]

[0098] L 24 =δ 2 *tan(ε 2 )*n air .

[0099] When the Wollaston polarizing prism and the roof glass wedge are glued together, H 3 =0.00mm, we can get: δ 1 =0.86mm, L 1 =22.03mm,δ 2 =1.02mm, L 2 =22.00mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =1.88mm;

[0100] When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =0.50mm, we can get:δ 1 =0.94mm, L 1 =22.52mm,δ 2 =1.11mm, L 2 =22.49mm; At this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =2.05mm;

[0101] When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =1.50mm, we can get:δ 1 =1.10mm, L 1 =23.51mm,δ 2 =1.29mm, L 2 =23.48mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =2.39mm.

[0102] The present invention adopts a "polarization splitting prism assembly" to separate the independent polarization imaging light paths of the two surfaces in space and then obtain images by the lens and the ordinary camera. It is different from the previous patent application (application number 202010250856X). The independent polarization imaging light paths of the two surfaces of application number 202010250856X are completely overlapped in space before entering the lens and the camera, and the two images are obtained by the two quadrants of a special polarization camera.

[0103] The present invention uses polarization image splitting method to realize simultaneous equal optical path confocal detection method of double sides of crystal grains, which is characterized in that: the detection device comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a top right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the top right-angle image rotation prism are respectively located on the front side of the semiconductor crystal grain and directly above the top surface; the polarization cube beam splitter and the top right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; the second right-angle surface of the side right-angle image rotation prism is opposite to the side surface of the semiconductor crystal grain; The inclined surface of the side right-angle image-turning prism is arranged obliquely with respect to the optical axis of the telecentric imaging lens, and the two right-angle surfaces of the sky-plane right-angle image-turning prism are respectively opposite to the sky-plane of the semiconductor crystal grain and the second surface of the polarization cube beam splitter; the polarization image-splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens; a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the polarization cube beam splitter, or a coaxial external illumination light source is arranged between the side right-angle image-turning prism and the side surface of the semiconductor crystal grain, and between the sky-plane right-angle image-turning prism and the sky-plane of the semiconductor crystal grain, respectively; the sky-plane and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera through the right-angle image-turning prism, the polarization cube beam splitter, and the polarization image-splitting prism assembly with equal optical path and confocal polarization, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera;

[0104] Polarization imaging illumination light path: When the illumination light source passes through the polarization cube beam splitter, it is divided into two beams of linear polarized light with mutually perpendicular polarization directions, namely the p-component and the s-component; one beam of p-component polarized light passes through the top right-angle image-turning prism to illuminate the top surface of the semiconductor crystal grain to be measured; and the other beam of s-component polarized light passes through the side right-angle image-turning prism to illuminate the side surface of the semiconductor crystal grain to be measured. The two beams of linear polarized light with mutually perpendicular vibration directions illuminate the two adjacent surfaces of the semiconductor crystal grain respectively;

[0105] Polarization imaging optical path:

[0106] Two beams of linear polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to produce diffuse reflected light; the s-component of the imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly. The double-sided image output from the polarization image-splitting prism assembly obtains independent images of both sides on an ordinary CMOS or CCD camera.

[0107] The polarization cube beam splitter of the present application is a conventional polarization optical element, which is produced by Fujian Foctek Optoelectronics Co., Ltd. and others. It is formed by coating a polarization splitting film on the inclined surface of a right-angle prism, and then gluing the inclined surfaces of another right-angle prism of the same size to each other.

[0108] Advantages of the new detection device of the present invention:

[0109] 1) Simultaneous equal-path confocal polarization imaging detection of adjacent two sides of semiconductor grains, i.e., △ = 0 (or quasi-equal-path confocal imaging detection, △ ≈ 0), without the need to use a large-field telecentric lens to compensate for the optical path difference of double-sided polarization imaging;

[0110] 2) The utilization rate of illumination light using polarized light beam splitter is as high as 100%, and the illumination efficiency of double-light path and double-polarized light is high, while the light utilization rate of ordinary beam splitter prism is 50%;

[0111] 3) The adjacent double-sided polarization imaging optical path of semiconductor grains can achieve completely equal illumination;

[0112] 4) A specially designed polarization splitting prism assembly is used to obtain two polarized imaging light beams with polarization directions perpendicular to each other. The polarization splitting prism assembly is composed of a Wollaston polarization prism, i.e., a Wollaston polarization prism (or a Rochon or Se'narmont polarization prism) and a matching roof-shaped prism. The spacing δ of the double-sided images depends on the optical design of the polarization splitting prism assembly and can be selected as δ=1.8-2.5mm.

[0113] 5) Ordinary CMOS or CCD cameras are used to separate two different polarization (0 degree and 90 degree polarization directions) imaging light paths and simultaneously collect images of adjacent double sides, with short image processing time and high speed; the cost of ordinary CMOS or CCD cameras is about 10% of that of polarization cameras; even if the cost of the polarization image splitting prism assembly is increased, the cost of the detection system can be effectively reduced.

[0114] 6) The device for simultaneously detecting polarization imaging of adjacent double sides of semiconductor grains has a simple and compact structure and is easy to assemble and debug.

[0115] 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 device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method, Features: The invention comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a sky right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located on the positive side of the semiconductor crystal grain and directly above the sky surface; the polarization cube beam splitter and the sky right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; the second right-angle surface of the side right-angle image rotation prism is aligned with the first surface of the polarization cube beam splitter; The side surfaces of the crystal grain are opposite to each other, the inclined surface of the side right-angle image-turning prism is arranged obliquely with the optical axis of the telecentric imaging lens, and the two right-angle surfaces of the sky-surface right-angle image-turning prism are respectively opposite to the sky surface of the semiconductor crystal grain and the second surface of the polarization cube beam splitter; the polarization image-splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens side, a coaxial external illumination light source is arranged beside the fourth surface opposite to the second surface of the polarization cube beam splitter, the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera by equal optical path confocal polarization through the right-angle image-turning prism, the polarization cube beam splitter and the polarization image-splitting prism assembly, and independent images of the two sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera.

2. A device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method, Features: The invention comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a sky right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located on the positive side of the semiconductor crystal grain and directly above the sky surface; the polarization cube beam splitter and the sky right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; the second right-angle surface of the side right-angle image rotation prism is opposite to the side surface of the semiconductor crystal grain; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located on the optical axis of the telecentric imaging lens; The inclined surface of the angle-turning prism is arranged to be inclined with respect to the optical axis of the telecentric imaging lens. The two right-angle surfaces of the sky-plane right-angle-turning prism are respectively opposite to the sky-plane of the semiconductor crystal grain and the second surface of the polarization cube beam splitter. The polarization image splitting prism assembly comprises a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism near the telecentric imaging lens. Coaxial external illumination light sources are respectively arranged between the side right-angle-turning prism and the side surface of the semiconductor crystal grain, and between the sky-plane right-angle-turning prism and the sky-plane of the semiconductor crystal grain. The sky-plane and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera by equal optical path confocal polarization through the right-angle-turning prism, the polarization cube beam splitter and the polarization image splitting prism assembly, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera.

3. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 1 or 2, Features: Polarization imaging illumination light path: When the illumination light source passes through the polarization cube beam splitter, it is divided into two beams of linear polarized light with mutually perpendicular polarization directions, namely the p-component and the s-component; one beam of p-component polarized light passes through the top right-angle image-turning prism to illuminate the top surface of the semiconductor crystal grain to be measured; and the other beam of s-component polarized light passes through the side right-angle image-turning prism to illuminate the side surface of the semiconductor crystal grain to be measured. The two beams of linear polarized light with mutually perpendicular vibration directions illuminate the two adjacent surfaces of the semiconductor crystal grain respectively.

4. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 3, Features: Two beams of linear polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to produce diffuse reflected light; the s-component of the imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly. The double-sided image output from the polarization image-splitting prism assembly obtains independent images of both sides on an ordinary CMOS or CCD camera.

5. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 1 or 2, Features: The working distance WD of the celestial imaging optical path is d / 2, where d is the length of the right-angle side of the prism; the polarization cube beam splitter is glued to the side right-angle image rotation prism and their centers coincide, and the working distance WD of the side imaging optical path is D / 2+d / 2, where D is the width of the transparent glass stage; the coaxial external illumination light source is monochromatic light or a quasi-monochromatic light source with a certain spectral bandwidth.

6. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 1 or 2, Features: The size of the top right-angle image-transfer prism is 15*15*15mm, the size of the side right-angle image-transfer prism is 15*15*15mm, the size of the polarization cube beam splitter is 15*15*15mm, the size of the Wollaston polarization prism is 10*10*11mm, and the size of the roof prism is 10*10*3.17mm.

7. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 1 or 2, Features: The images formed by the polarized light output from the polarization splitting prism component on the adjacent surfaces of the semiconductor crystal grains are separated in space; using a common CMOS or CCD camera, equal optical path confocal imaging detection in which the polarization of the top and side light paths of the semiconductor crystal grains can be separated respectively is obtained; or using a common CMOS or CCD camera, complete equal optical path confocal polarization imaging detection in which the polarization directions of the top and side imaging light paths can be separated at 0 degrees and 90 degrees is obtained respectively.

8. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 1 or 2, Features: Set the size of the Wollaston polarizing prism made of calcite to L 1 *W 1 *H 1 =10*10*11mm, the prism vertex angle is θ=45°, and the refractive indexes of o-light and e-light are n o =1.658 and n e =1.486; the size of the roof prism made of K9 material is L 2 *W 2 *H 2 =10*10*3.17mm, the angles between the left and right ridges and the horizontal direction are ε 1 and ε 2 , the refractive index is n k9 =1.5163; the air gap height between the Wollaston polarizing prism and the roof prism is H 3 The refractive index of air is n air =1.0; set the p-component of the side imaging beam to be incident on the first prism of the Wollaston polarizing prism as e-light vertically, and to be converted into o-light at the second prism of the Wollaston polarizing prism, and to be shifted to the left and finally imaged on the left side of the camera; set the s-component of the sky imaging beam to be incident on the first prism of the Wollaston polarizing prism as o-light vertically, and to be converted into e-light at the second prism of the Wollaston polarizing prism, and to be shifted to the right and finally imaged on the right side of the camera; Set the refraction angle of the side light path from the first prism of the Wollaston polarizing prism to the second prism to be α 1 The refraction angle from the Wollaston polarizing prism to the air gap is β 1 , the refraction angle of the incident light from the air gap to the roof prism is γ 1 Then we have: For the skylight path, the refraction angle from the first prism of the Wollaston polarizing prism to the second prism is set to α 2 The refraction angle from the Wollaston polarizing prism to the air gap is β 2 , the refraction angle of the roof prism incident from the air gap is γ 2 Then we have: The optical paths of the side light path at the Wollaston polarizing prism, the air gap, the roof prism, and the vertical emission to the same level as the top of the roof prism are L 11 , L 12 , L 13 and L 14 The resulting offsets are δ 11 , δ 12 and δ 13 ; The total optical path is L 1 , the total offset is δ 1 , then: d 1 =d 11 +d 12 +d 13 L 1 =L 11 +L 12 +L 13 +L 14 d 12 =H 3 *tan(β 1 ) Depend on Can be obtained: L 14 =d 1 *tan(e 1 )*n air For the skylight path, the optical path lengths at the Wollaston polarizing prism, the air gap, the ridge-shaped glass wedge, and the vertical emission to the same level as the top of the ridge-shaped prism are set to be L 21 , L 22 , L 23 and L 24 The resulting offsets are δ 21 , δ 22 and δ 23 ; The total optical path is L 2 , the total offset is δ 2 , then: d 2 =d 21 +d 22 +d 23 L 2 =L 21 +L 22 +L 23 +L 24 d 22 =H 3 *tan(β 2 ) Depend on Can be obtained: L 24 =d 2 *tan(e 2 )*n air 。 9. The device for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method according to claim 8, Features: When the Wollaston polarizing prism and the roof glass wedge are glued together, H 3 =0.00mm, we can get: δ 1 =0.86mm, L 1 =22.03mm,δ 2 =1.02mm, L 2 =22.00mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =1.88mm; When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =0.50mm, we can get:δ 1 =0.94mm, L 1 =22.52mm,δ 2 =1.11mm, L 2 =22.49mm; At this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =2.05mm; When the air gap H between the Wollaston polarizing prism and the roof glass wedge 3 =1.50mm, we can get:δ 1 =1.10mm, L 1 =23.51mm,δ 2 =1.29mm, L 2 =23.48mm; at this time, the optical path difference of the two adjacent imaging light paths is: Δ = L 1 -L 2 =0.03mm, double-sided imaging distance: δ=δ 1 +δ 2 =2.39mm.

10. A method for realizing simultaneous equal-optical-path confocal detection of both sides of a grain using polarization image splitting method. Features: The detection device comprises a CMOS or CCD camera, a telecentric imaging lens, a polarization image splitting prism assembly, a polarization cube beam splitter, 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 side right-angle image rotation prism and a sky right-angle image rotation prism are respectively arranged on the optical path between the semiconductor crystal grain and the polarization cube beam splitter; the side right-angle image rotation prism and the sky right-angle image rotation prism are respectively located on the positive side of the semiconductor crystal grain and directly above the sky surface; the polarization cube beam splitter and the sky right-angle image rotation prism are at the same horizontal height; the side right-angle image rotation prism and the polarization cube beam splitter 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 aligned and glued with the first surface of the polarization cube beam splitter; the second right-angle surface of the side right-angle image rotation prism is opposite to the side surface of the semiconductor crystal grain; the oblique surface of the side right-angle image rotation prism is aligned with the telecentric imaging lens; The optical axis of the head is tilted, and the two right-angled 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 polarization cube beam splitter; the polarization image-splitting prism assembly includes a Wollaston polarization prism attached to the third surface of the polarization cube beam splitter and a roof prism located on the Wollaston polarization prism close to the telecentric imaging lens side, and a coaxial external illumination light source is provided beside the fourth surface opposite to the second surface of the polarization cube beam splitter, or a coaxial external illumination light source is provided between the side right-angle image-turning prism and the side surface of the semiconductor crystal grain, and between the sky right-angle image-turning prism and the sky surface of the semiconductor crystal grain, respectively, and the sky surface and the side surface of the semiconductor crystal grain are respectively imaged on the sensor surface of the CMOS or CCD camera through the right-angle image-turning prism, the polarization cube beam splitter, and the polarization image-splitting prism assembly with equal optical path and confocal polarization, and independent images of both sides of the semiconductor crystal grain are obtained on the CMOS or CCD camera; Polarization imaging illumination light path: When the illumination light source passes through the polarization cube beam splitter, it is divided into two beams of linear polarized light with mutually perpendicular polarization directions, namely the p-component and the s-component; one beam of p-component polarized light passes through the top right-angle image-turning prism to illuminate the top surface of the semiconductor crystal grain to be measured; and the other beam of s-component polarized light passes through the side right-angle image-turning prism to illuminate the side surface of the semiconductor crystal grain to be measured. The two beams of linear polarized light with mutually perpendicular vibration directions illuminate the two adjacent surfaces of the semiconductor crystal grain respectively; Polarization imaging optical path: Two beams of linear polarized light with mutually perpendicular vibration directions illuminate two adjacent faces of the semiconductor crystal grain to produce diffuse reflected light; the s-component of the imaging light beam on the top face of the semiconductor crystal grain is reflected by the top face right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly; and the p-component imaging light beam on the side face of the semiconductor crystal grain is transmitted by the side right-angle image-turning prism and the polarization cube beam splitter into the polarization image-splitting prism assembly. The double-sided image output from the polarization image-splitting prism assembly obtains independent images of both sides on an ordinary CMOS or CCD camera.

Images