Endoscopic imaging system and endoscope

Abstract

The application discloses an endoscope imaging system and an endoscope, and belongs to the technical field of endoscope imaging. The endoscope imaging system comprises an endoscope light inlet, a light splitter, a first sensor, a converging lens group and a second sensor. The light splitter is used for splitting a received light beam into a first light beam and a second light beam, wherein the wavelength of the first light beam is smaller than that of the second light beam, and the first light beam and the second light beam are guided to the first sensor and the converging lens group respectively. The converging lens group transmits the converged second light beam to the second sensor. In this way, the energy of the unit area of the light spot received by the light receiving surface of the second sensor can be improved, the definition of the image formed by the second sensor can be improved, and the registration accuracy of the images formed by the two image sensors can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of endoscope imaging, and in particular to an endoscope imaging system and an endoscope. BACKGROUND

[0002] An endoscope is a detection instrument including an illumination system and an imaging system, and is one of important surgical instruments in minimally invasive surgery.

[0003] An endoscope imaging system has an endoscope light inlet, a beam splitter and two image sensors. The beam splitter receives a light beam incident from the endoscope light inlet, divides the received light beam into two light beams with different wavelengths, and transmits the two light beams to the two image sensors, respectively, so as to acquire two different images through the two image sensors. Image registration of the two images can more completely acquire image information.

[0004] However, in the above imaging system, the image formed by one of the image sensors may have poor definition, which may result in low registration accuracy of the images formed by the two image sensors. SUMMARY

[0005] Embodiments of the present application provide an endoscope imaging system and an endoscope. The technical solutions are as follows:

[0006] According to an aspect of the present application, an endoscope imaging system is provided, which comprises:

[0007] an endoscope light inlet, a beam splitter, a first sensor, a converging lens group and a second sensor;

[0008] The beam splitter is located on one side of the endoscope light inlet. The beam splitter includes a lens group light inlet, a first light outlet and a second light outlet. The beam splitter is configured to receive a light beam incident from the endoscope light inlet through the lens group light inlet, divide the received light beam into a first light beam and a second light beam, and emit the first light beam out of the beam splitter through the first light outlet and emit the second light beam out of the beam splitter through the second light outlet. The wavelength of the first light beam is less than the wavelength of the second light beam.

[0009] The first sensor is located outside the first light outlet. The converging lens group and the second sensor are arranged in sequence along a direction away from the second light outlet outside the second light outlet.

[0010] Optionally, the converging lens group includes a first lens and a second lens.

[0011] The first lens is located on a side of the second lens away from the second sensor, the first lens has positive focal power, the second lens has negative focal power, and the first lens and the second lens are coaxial.

[0012] Optionally, the first lens is a double convex lens, and the second lens is a double concave lens.

[0013] The first lens and the second lens are cemented.

[0014] Optionally, the first lens has a first light entrance surface and a first light exit surface, a ratio of a curvature radius value of the first light entrance surface to a curvature radius value of the first light exit surface ranges from 0.6 to 1, and a ratio of an Abbe number to a refractive index of a material of the first lens ranges from 26 to 32.

[0015] The second lens has a second light entrance surface and a second light exit surface, a ratio of a curvature radius value of the second light entrance surface to a curvature radius value of the second light exit surface ranges from 0.45 to 1, and a ratio of an Abbe number to a refractive index of a material of the second lens ranges from 14 to 20.

[0016] Optionally, the converging lens group further comprises a third lens and a fourth lens located between the second lens and the second sensor, and the third lens and the fourth lens are sequentially arranged in a direction away from the second lens.

[0017] The third lens has positive focal power, the fourth lens has negative focal power, and the first lens, the second lens, the third lens, and the fourth lens are coaxial.

[0018] Optionally, the first lens is a double convex lens, the second lens is a meniscus lens, and a convex surface of the first lens and a concave surface of the second lens are cemented.

[0019] The third lens is a double convex lens, the fourth lens is a double concave lens, and the third lens and the fourth lens are cemented.

[0020] Optionally, the first light beam is a visible light beam, the second light beam is a near-infrared light beam, the first sensor is a visible light image sensor, and the second sensor is a near-infrared light image sensor.

[0021] Optionally, the imaging system further comprises a first filter and a second filter.

[0022] The first filter is located between the endoscope light entrance and the light splitting lens group, the first filter is used to transmit the visible light beam and the near-infrared light beam and block light beams other than the visible light beam and the near-infrared light beam.

[0023] The second filter is located between the beam splitter and the second sensor, and is configured to transmit the near-infrared light beam and block other light beams.

[0024] Optionally, the endoscope imaging system further comprises a light guide lens group located between the endoscope light inlet and the beam splitter, and configured to receive the light beam incident on the endoscope light inlet and guide the light beam to the beam splitter.

[0025] Optionally, the imaging system further comprises an adjusting assembly, wherein the light guide lens group is mounted in the adjusting assembly, and the adjusting assembly is configured to drive the light guide lens group to move between the endoscope light inlet and the beam splitter along a direction parallel to an optical axis of the light guide lens group.

[0026] According to another aspect of the present application, an endoscope is provided, which comprises the endoscope imaging system described above.

[0027] The technical scheme provided by the embodiments of the present application has at least the following beneficial effects:

[0028] The endoscope imaging system comprises an endoscope light inlet, a beam splitter, a first sensor, a converging lens group and a second sensor. The beam splitter is configured to split a light beam incident on the endoscope light inlet into a first light beam and a second light beam, and guide the first light beam and the second light beam to the first sensor and the converging lens group, respectively. The converging lens group is configured to transmit the converged second light beam to the second sensor. The wavelength of the first light beam is less than the wavelength of the second light beam. In this way, the energy per unit area of the light spot received by the light receiving surface of the second sensor can be improved, thereby improving the definition of the image formed by the second sensor, and further improving the registration accuracy of the images formed by the two image sensors. The registration accuracy of the images formed by the two image sensors in the related art is low, and the effect of improving the registration accuracy of the images formed by the two image sensors in the endoscope imaging system is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0030] Figure 1 is a structural schematic diagram of an endoscope imaging system provided by an embodiment of the present application;

[0031] Figure 2is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0032] Figure 3 is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0033] Figure 4 is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0034] Figure 5 is Figure 4 is a structural schematic diagram of a light guide mirror group in the endoscope imaging system shown in the figure;

[0035] Figure 6 is a modulation transfer function curve diagram of a visible light path provided by an embodiment of the present application;

[0036] Figure 7 is Figure 6 is a partial curve diagram in the modulation function curve diagram shown in the figure;

[0037] Figure 8 is a modulation transfer function curve diagram of a near-infrared light path provided by an embodiment of the present application;

[0038] Figure 9 is Figure 8 is a partial curve diagram in the modulation function curve diagram shown in the figure;

[0039] Figure 10 is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0040] Figure 11 is Figure 10 is a structural schematic diagram of a converging mirror group in the endoscope imaging system shown in the figure;

[0041] Figure 12 is a modulation transfer function curve diagram of another near-infrared light path provided by an embodiment of the present application;

[0042] Figure 13 is Figure 12 is a partial curve diagram in the modulation function curve diagram shown in the figure;

[0043] Figure 14 is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0044] Figure 15 is a structural schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0045] Figure 16is an explosion structure schematic diagram of a beam splitter provided by an embodiment of the present application;

[0046] Figure 17 is a structure schematic diagram of another endoscope imaging system provided by an embodiment of the present application;

[0047] Figure 18 is a structure schematic diagram of another endoscope imaging system provided by an embodiment of the present application.

[0048] The specific embodiments of the present application have been shown by the above figures, and will be described in more detail hereinafter. These figures and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present application more clear, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

[0050] An endoscope is a detection instrument including an illumination system and an imaging system, and is one of important surgical instruments in minimally invasive surgery. The endoscope includes a light source assembly, an imaging system and a display assembly, wherein the imaging system includes an image sensor. In the use process of the endoscope, a doctor inserts the endoscope into the abdominal cavity of a patient, so that the endoscope reaches a lesion position, and then uses the light source assembly to illuminate, uses the image sensor in the imaging system to acquire an image, and transmits the acquired image to the display assembly to display, so that the doctor can observe the lesion condition in real time.

[0051] When diagnosing diseases by using the endoscope, the acquired visible light image is image-registered with other waveband images (such as near-infrared light images) other than visible light, which can improve the diagnosis efficiency and accuracy. An endoscope imaging system has an endoscope light inlet, a beam splitter and two image sensors. The beam splitter receives a light beam incident from the endoscope light inlet, divides the received light beam into two light beams with different wavelengths, and then transmits the two light beams to the two image sensors respectively, so as to acquire two different images by the two image sensors. Image registration of the two images can more completely acquire image information.

[0052] Image registration refers to an image processing technology of matching and superimposing two or more images acquired by different image sensors. Registration accuracy is an important technical index of image registration, and the registration accuracy can determine the subsequent processing effect of the image. The higher the registration accuracy is, the better the image processing effect will be. If the registration accuracy of the two images is relatively low, ghosting and other problems will occur in the registration process of the two images, resulting in poor imaging effect of the finally acquired image.

[0053] The energy per unit area of the light spot received by the light receiving surface of the two image sensors in the imaging system is different, which can cause the image formed by one of the image sensors to have poor definition, and can further cause the registration accuracy of the images formed by the two image sensors to be low.

[0054] Embodiments of the present application provide an endoscope imaging system and an endoscope, which can solve the problems in the related art.

[0055] Reference is made to Figure 1 , Figure 1 is a structural schematic diagram of an endoscope imaging system 10 provided by an embodiment of the present application. The endoscope imaging system 10 can include an endoscope light inlet 11, a beam splitter group 12, a first sensor 13, a converging lens group 14, and a second sensor 15. A light beam can enter the endoscope imaging system 10 through the endoscope light inlet 11, and the light beam can include visible light and non-visible light.

[0056] The beam splitter group 12 can be located on one side of the endoscope light inlet 11, and the beam splitter group 12 includes a lens group light inlet 12a, a first light outlet 12b, and a second light outlet 12c. The beam splitter group 12 is configured to receive the light beam incident from the endoscope light inlet 11 through the lens group light inlet 12a, and divide the received light beam into a first light beam S1 and a second light beam S2. The first light beam S1 exits the beam splitter group 12 through the first light outlet 12b, and the second light beam S2 exits the beam splitter group 12 through the second light outlet 12c. The wavelength of the first light beam S1 is less than the wavelength of the second light beam S2. Because the wavelengths of the first light beam S1 and the second light beam S2 are different, the losses of the first light beam S1 and the second light beam S2 during transmission are different, resulting in different transmission efficiencies of the first light beam S1 and the second light beam S2. In the embodiment of the present application, the energy of the second light beam S2 exiting the beam splitter group 12 is less than the energy of the first light beam S1.

[0057] The first sensor 13 is located outside the first light outlet 12b, and the light receiving surface of the first sensor 13 can receive the first light beam S1 exiting the first light outlet 12b. The converging lens group 14 and the second sensor 15 are arranged in sequence along a direction away from the second light outlet 12c outside the second light outlet 12c. The converging lens group 14 can receive the second light beam S2 exiting the second light outlet 12c, and after converging the received second light beam S2, the converging lens group 14 can irradiate the second light beam S2 to the second sensor 15. The light receiving surface of the second sensor 15 can receive the converged second light beam S2. In this way, the converging lens group 14 can improve the energy per unit area of the light spot received by the light receiving surface of the second sensor 15 by converging the second light beam S2 and transmitting the converged light beam to the second sensor 15, thereby improving the definition of the image formed by the second sensor 15, and further improving the registration accuracy of the images formed by the two image sensors.

[0058] To sum up, the embodiment of the present application provides an endoscope imaging system, which comprises an endoscope light inlet, a light splitting mirror set, a first sensor, a converging mirror set and a second sensor. The light splitting mirror set is used for splitting the received light beam into a first light beam and a second light beam, wherein the wavelength of the first light beam is smaller than that of the second light beam, and guiding the first light beam and the second light beam to the first sensor and the converging mirror set respectively. The converging mirror set transmits the converged second light beam to the second sensor. In this way, the energy per unit area of the light spot received by the light receiving surface of the second sensor can be improved, the definition of the image formed by the second sensor can be improved, and the registration accuracy of the images formed by the two image sensors can be improved. The problem of low registration accuracy of the images formed by the two image sensors in the related art is solved, and the effect of improving the registration accuracy of the images formed by the two image sensors in the endoscope imaging system is achieved.

[0059] It should be noted that the endoscope light inlet 11, the mirror set light inlet 12a, the first light outlet 12b and the second light outlet 12c in the embodiment of the present application can be virtual regions in the endoscope imaging system 10. For example, the endoscope light inlet 11 can be a light inlet region through which the external light beam passes when entering the endoscope imaging system, the mirror set light inlet 12a can be a light inlet region through which the light beam passes when entering the light splitting mirror set 12, and the first light outlet 12b and the second light outlet 12c can be light outlet regions through which the first light beam S1 and the second light beam S2 respectively pass when exiting the light splitting mirror set 12.

[0060] Alternatively, the endoscope light inlet 11, the mirror set light inlet 12a, the first light outlet 12b and the second light outlet 12c can also be actual structures. For example, the endoscope imaging system 10 can further comprise a protective lens, which can be the endoscope light inlet of the endoscope imaging system. The light splitting mirror set 12 can be a light splitting prism, which can comprise a light inlet surface and two light outlet surfaces. The light inlet surface of the light splitting prism can be the mirror set light inlet 12a, and the two light outlet surfaces can be the first light outlet 12b and the second light outlet 12c respectively.

[0061] Optionally, the first light beam S1 is a visible light beam, the second light beam S2 is a near-infrared light beam, the first sensor 13 is a visible light image sensor, and the second sensor 15 is a near-infrared light image sensor. The wavelength range of the first light beam S1 can be 400 nanometers (nm) to 700 nanometers (nm), and the wavelength range of the second light beam S2 can be 810 nanometers (nm) to 890 nanometers (nm). It should be noted that in the field of surgical technology, indocyanine green near-infrared light imaging technology can be applied in clinical practice. Indocyanine green (English: indocyanine green; abbreviation: ICG) is a near-infrared light contrast agent with good biocompatibility, which can be excited by light with a wavelength of 750 nm to 800 nm and emit near-infrared light, thereby realizing tissue and organ imaging. The imaging spectrum of the endoscope imaging system 10 includes visible light and near-infrared light, that is, the endoscope imaging system 10 can acquire near-infrared light images and visible light images, which can improve the accuracy of the images acquired by the endoscope imaging system 10.

[0062] In the related art, the endoscope imaging system 10 includes an endoscope light inlet 11, a beam splitter 12, and two image sensors. The beam splitter 12 receives the light beams incident from the endoscope light inlet 11, and after dividing the received light beams into two light beams with different wavelengths, the two light beams are transmitted to the two image sensors, respectively. The paths of the light beams received by the two image sensors are the same, and the areas of the light spots received by the two image sensors are also equal. Due to the large loss of near-infrared light during transmission in the optical path, the energy of the near-infrared light is weak. When the areas of the light spots received by the two image sensors are the same, the energy per unit area of the light spot received by the light receiving surface of the infrared light image sensor is small, thereby affecting the detection sensitivity of the near-infrared light image sensor, making the display of the near-infrared light marked area in the image acquired by the near-infrared light image sensor inaccurate, and the clarity of the formed image poor, which may further result in low registration accuracy of the visible light image and the near-infrared light image formed by the two image sensors, respectively. In the embodiment of the present application, the second light beam S2 is converged by the converging lens group 14, so that the optical path elements corresponding to the first light beam S1 and the second light beam S2 have different focal lengths. The areas of the light spots received by the visible light image sensor and the near-infrared light image sensor are different, thereby the area of the light spot received by the near-infrared light image sensor can be reduced, the energy per unit area of the light spot received by the light receiving surface of the second sensor 15 can be increased, the detection sensitivity of the near-infrared light sensor can be improved, and the registration accuracy of the visible light image and the near-infrared light image can be improved.

[0063] Figure 2 is another structural schematic diagram of an endoscope imaging system 10 provided by the embodiment of the present application. Please refer to Figure 2Optionally, the converging lens set 14 can include a first lens 141 and a second lens 142. The first lens 141 is located on the side of the second lens 142 away from the second sensor 15, the first lens 141 has a positive focal power, the second lens 142 has a negative focal power, and the first lens 141 and the second lens 142 are coaxial. The first lens 141 with a positive focal power can converge the second light beam S2, the second lens 142 with a negative focal power can diverge the second light beam S2 passing through the first lens 141, and overall, the first lens 141 and the second lens 142 can converge the second light beam S2 to reduce the area of the light spot received by the near-infrared light image sensor, improve the energy per unit area of the light spot received by the light receiving surface of the second sensor 15, and such arrangement can make the converging lens set 14 have better aberration correction capability.

[0064] Figure 3 is another structural schematic diagram of an endoscope imaging system 10 provided by the embodiment of the present application, please refer to Figure 3 Optionally, the first lens 141 can be a double convex lens, the first lens 141 has a first light entrance surface and a first light exit surface, the ratio of the curvature radius (R) value of the first light entrance surface to the curvature radius (R) value of the first light exit surface ranges from 0.6 to 1, the curvature radius (R) value of the first light entrance surface and the curvature radius (R) value of the first light exit surface both range from 15 mm to 30 mm, the refractive index of the material of the first lens 141 ranges from 1.7 to 1.9, and the focal length (f) value of the first lens 141 ranges from 10 mm to 15 mm. The second lens 142 is a double concave lens, the second lens 142 has a second light entrance surface and a second light exit surface, the ratio of the curvature radius (R) value of the second light entrance surface to the curvature radius (R) value of the second light exit surface ranges from 0.45 to 1, the curvature radius (R) value of the second light entrance surface and the curvature radius (R) value of the second light exit surface both range from 15 mm to 30 mm, the refractive index of the material of the second lens 142 ranges from 1.7 to 1.9, and the focal length (f) value of the second lens 142 ranges from -13 mm to -18 mm. Such arrangement can make the first lens 141 and the second lens 142 converge the second light beam S2 while eliminating the aberration of the second light beam S2 during imaging, thereby improving the imaging quality of the second light beam S2.

[0065] It should be noted that the lenses in the converging lens group 14 can be spherical lenses or aspherical lenses. The radius of curvature of the lens surface of a spherical lens in the converging lens group 14 refers to the spherical radius of the lens surface, and the radius of curvature of an aspherical lens refers to the radius at the vertex of the lens surface. In order to more clearly indicate the bending direction of the lens surface, assuming that the direction from the image plane to the object plane is positive, the radius of curvature of the lens surface in the lens group is positive when the direction of the lens surface to the center of the lens is the same as the direction from the image plane to the object plane, and the radius of curvature of the lens surface is negative when the direction of the lens surface to the center of the lens is opposite to the direction from the image plane to the object plane. It should be noted that the side where the image sensor is located in the present application is the image plane, and the side away from the image sensor in the transmission direction of the light beam is the object plane.

[0066] The first lens 141 and the second lens 142 are cemented, and the cemented first lens 141 and the second lens 142 can be used for condensing light to reduce the area of the light spot received by the near-infrared light image sensor, thereby increasing the energy per unit area of the light spot received by the light receiving surface of the second sensor 15. The focal length f of the cemented first lens 141 and the second lens 142 is 70 mm to 90 mm, and the ratio (f / d) of the focal length f to the central thickness d of the cemented first lens 141 and the second lens 142 is 25 to 29.

[0067] The cemented first lens 141 and the second lens 142 can be used to correct chromatic aberration, so that the converging lens group 14 has the ability to correct chromatic aberration and aberration at the same time, and also makes the lens group have better resolution while the number of lenses in the lens group is relatively small, thereby reducing the volume of the endoscope imaging system 10. The Abbe number (also referred to as the dispersion coefficient) of the material of the first lens 141 in the cemented first lens 141 and the second lens 142 and the Abbe number of the material of the second lens 142 can be quite different. The ratio of the Abbe number to the refractive index of the material of the first lens 141 ranges from 26 to 32, and the ratio of the Abbe number to the refractive index of the material of the second lens 142 ranges from 14 to 20. For example, the Abbe number of the material of the first lens 141 ranges from 45 to 55, and the Abbe number of the material of the second lens 142 ranges from 20 to 30. Compared with the second lens 142, the material of the first lens 141 is a low-dispersion material, and the material of the second lens 142 is a high-dispersion material. The dispersion of the first lens 141 and the second lens 142 can be mutually compensated to make the cemented first lens 141 and the second lens 142 have better correction ability for chromatic aberration.

[0068] In the embodiment of the present application, the first lens 141 and the second lens 142 in the converging lens group 14 can both be spherical lenses. For example, as shown in FIG. 2, the first lens 141 and the second lens 142 are both spherical lenses. Figure 3As shown, the first lens 141 can have a first light entrance surface L1 and a first cemented surface, which is the first light exit surface L2 of the first lens 141. The light entrance surface L1 and the first cemented surface of the first lens 141 can both be spherical surfaces. The second lens 142 has a second cemented surface and a second light exit surface L3, and the second cemented surface is the second light entrance surface L4 of the second lens 142. The second cemented surface and the second light exit surface of the second lens 142 can both be spherical surfaces. The first cemented surface in the first lens 141 is cemented with the second cemented surface in the second lens 142.

[0069] Alternatively, the first lens 141 and the second lens 142 in the converging lens group 14 can both be aspherical lenses, which can correct aberrations (for example, field curvature, distortion, and spherical aberration) in the endoscope imaging system 10, so that the imaging quality of the endoscope imaging system 10 is better.

[0070] Figure 4 is another structural schematic diagram of an endoscope imaging system 10 provided by the application, please refer to Figure 4 Alternatively, the endoscope imaging system 10 can further include a light guide lens group 16, which is located between the endoscope light entrance 11 and the light splitting lens group 12, and is used to receive the light beam incident by the endoscope light entrance 11 and guide the light beam to the light splitting lens group 12. The light guide lens group 16 can include a plurality of lenses, which can be a first cemented lens 161, a fifth lens 162, a sixth lens 163, a seventh lens 164, and a second cemented lens 165, wherein the fifth lens 162 has a negative focal power, the sixth lens 163 has a positive focal power, and the seventh lens 164 has a positive focal power. The focal length of the light guide lens group 16 can be 20mm-30mm.

[0071] As shown in Figure 4 The endoscope light entrance 11, the light guide lens group 16, the light splitting lens group 12, and the first sensor 13 can form a visible light path structure, and the endoscope light entrance 11, the light guide lens group 16, the light splitting lens group 12, the converging lens group 14, and the second sensor 15 can form a near-infrared light path structure. The light guide lens group 16 can be a common light path lens group for visible light and near-infrared light, wherein the focal length of the visible light path structure can be 20mm-30mm, and the focal length of the near-infrared light path structure can be 15mm-20mm. The chief ray incidence angle (CRA) of the first light beam S1 incident on the first sensor 13 is less than ±2°, and the chief ray incidence angle (CRA) of the second light beam S2 incident on the second sensor 15 is less than ±0.5°, which can make the visible light path and the near-infrared light path respectively meet the requirements of different image sensors for the chief ray incidence angle.

[0072] In this embodiment, a portion of the visible light path and the near-infrared light path pass through the same light guide mirror group 16. The focal lengths of the visible light path structure and the near-infrared light path structure can be different, making the effective pixel count of the visible light image sensor 2 to 4 times that of the near-infrared light image sensor. This allows the visible light image area acquired by the visible light image sensor to be larger than the near-infrared light image area acquired by the near-infrared light image sensor. In other words, it can increase the energy per unit area of ​​the light spot received by the light-receiving surface of the infrared light image sensor, thereby enabling the infrared light image sensor to detect more details and improving the registration accuracy and detection sensitivity of the endoscopic imaging system.

[0073] Figure 5 yes Figure 4 A schematic diagram of the structure of a light guide assembly 16 in the endoscopic imaging system 10 is shown below. Please refer to... Figure 5 The first cemented lens 161 may include a first sub-lens 1611 and a second sub-lens 1612. The first sub-lens 1611 may have positive optical power, and the second sub-lens 1612 may have negative optical power. The second cemented lens 165 may include a third sub-lens 1651 and a fourth sub-lens 1652. The third sub-lens 1651 may have negative optical power, and the fourth sub-lens 1652 may have positive optical power. The ratio of focal length to center thickness (f / d) of each lens in the light guide lens assembly 16 in this embodiment is shown in Table 1 below.

[0074] Table 1

[0075] Face number f / d value First cemented lens 161 4～6 Fifth lens 162 -11～-13 Sixth lens 163 -8～-10 Seventh lens 164 3～5 Second cemented lens 165 2～4

[0076] Figure 6 This is a schematic diagram of the modulation transfer function curve of a visible light optical path provided in an embodiment of this application. Figure 7 yes Figure 6 A schematic diagram of a portion of the modulation function curves shown. Figure 8 This is a schematic diagram of the modulation transfer function curve of a near-infrared optical path provided in an embodiment of this application. Figure 9 yes Figure 8 Please refer to the partial curve diagram shown in the modulation function graph. Figure 6 , Figure 7 , Figure 8 and Figure 9 The x-axis represents spatial frequency in line pairs per millimeter, and the y-axis represents the modulation transfer function. The modulation transfer function (MTF) curve describes the relationship between modulation density and the number of line pairs per millimeter in an image, used to evaluate the ability of optical elements to reproduce details of a scene.

[0077] Figure 6 The modulation transfer function curve in the middle can correspond to Figure 4 The optical performance of the optical elements between the endoscope inlet 11 and the first sensor 13 in the endoscopic optical system shown is as follows: the optical transfer function (MTF) of the endoscopic optical system is greater than 0.5 at a spatial frequency of 100 line pairs / mm (lp / mm), and greater than 0.25 at a spatial frequency of 180 line pairs / mm. Therefore, the optical elements in the endoscopic imaging system 10 of this embodiment have good resolution and image-resolving capabilities, and the imaging quality of the visible light path structure in the endoscopic imaging system 10 can meet the imaging requirements of endoscopes in this field.

[0078] Figure 8 The modulation transfer function curve in the middle can correspond to Figure 4 The optical performance of the optical elements between the endoscope inlet 11 and the second sensor 15 in the endoscopic optical system shown is as follows: the optical transfer function (MTF) of the endoscopic optical system is greater than 0.5 at a spatial frequency of 100 line pairs / mm and greater than 0.25 at a spatial frequency of 180 line pairs / mm. Therefore, the optical elements in the endoscopic imaging system 10 have good resolution and image-resolving capabilities, and the imaging quality of the near-infrared optical path structure in the endoscopic imaging system 10 meets the imaging requirements of endoscopes in this field. The endoscopic imaging system 10 in this embodiment can achieve 4K high-resolution imaging.

[0079] When testing the endoscopic imaging system 10, MTF curves corresponding to multiple fields of view (multiple image circle sizes) can be obtained. Under each field of view, there are curves in both the meridional (T) and sagittal (S) directions. To more clearly illustrate the extension of the curves in both directions of the endoscopic imaging system in this embodiment, Figure 7 It shows Figure 6 The curves in the meridian T and sagittal S directions are measured at a radius of 3.1000 mm. Figure 9 It shows Figure 8 The curves along the meridian T and sagittal S directions, measured at a radius of 2.1000 mm in the image circle, are derived from... Figure 7 and Figure 9It can be seen that in this embodiment, the MTF value difference between the curves corresponding to the meridional (T) and sagittal (S) directions of the endoscopic imaging system 10 is small. The closer the curves are in these two directions, the closer the MTF performance of the endoscopic imaging system 10 at the same location in the meridional and sagittal directions is, meaning that the imaging quality of the endoscopic imaging system 10 in this embodiment is better. The image circle refers to the circular, bright, and clear image area presented on the focal plane after the incident light passes through the endoscopic imaging system 10; it is also called the image size. Figure 6 , Figure 7 , Figure 8 and Figure 9 The values ​​following T and S in the image circle represent the radius of the image circle. For example, 0.9300 mm represents the MTF value measured at an image circle with a radius of 0.9300 mm. The full-field distortion of the endoscopic imaging system 10 in this embodiment can be less than 1%, and the distortion of the visible light path and the near-infrared light path are equal.

[0080] Figure 10 This is a schematic diagram of another endoscopic imaging system 10 provided in an embodiment of this application. Figure 11 yes Figure 10 A schematic diagram of the converging lens assembly 14 in the endoscopic imaging system 10 shown is provided below. Figure 10 and Figure 11 Optionally, the converging lens group 14 further includes a third lens 143 and a fourth lens 144 located between the second lens 142 and the second sensor 15. The third lens 143 and the fourth lens 144 are arranged sequentially in a direction away from the second lens 142. The third lens 143 has a positive optical power, the fourth lens 144 has a negative optical power, and the first lens 141, the second lens 142, the third lens 143 and the fourth lens 144 are coaxial.

[0081] The third lens 143 can be a biconvex lens, having a third incident surface and a third exit surface. The ratio of the radius of curvature (R) of the third incident surface to the radius of curvature (R) of the third exit surface ranges from 0.8 to 1. The refractive index of the material of the first lens ranges from 1.7 to 1.9, and the focal length (f) of the third lens ranges from 4 mm to 10 mm. The fourth lens 144 can be a biconcave lens, having a fourth incident surface and a fourth exit surface. The ratio of the radius of curvature (R) of the fourth incident surface to the radius of curvature (R) of the fourth exit surface ranges from 0.7 to 1. The refractive index of the material of the fourth lens ranges from 1.7 to 1.9, and the focal length (f) of the first lens ranges from -2 mm to -6 mm. This configuration allows the third lens 143 and the fourth lens 144 to converge the second beam S2 while simultaneously eliminating aberrations that occur during imaging of the second beam S2, thereby improving the imaging quality of the second beam S2.

[0082] The ratio of Abbe number and refractive index of the material of the third lens 143 ranges from 28 to 35, and the ratio of Abbe number and refractive index of the material of the fourth lens 144 ranges from 16 to 25. Compared with the fourth lens 144, the material of the third lens 143 is a low-dispersion material, and the material of the fourth lens 144 is a high-dispersion material. The dispersions of the third lens 143 and the fourth lens 144 can compensate for each other, so that the cemented third lens 143 and the fourth lens 144 have good correction ability of chromatic aberration.

[0083] In this way, the second light beam S2 can be converged by the third lens 143 with positive focal power in the converging lens group 14, and the second light beam S2 emitted from the third lens 143 can be diverged by the fourth lens 144 with negative focal power.

[0084] As shown in Figure 10 , the endoscope entrance 11, the light guide mirror group 16, the light splitting mirror group 12 and the first sensor 13 can form a visible light path structure, the endoscope entrance 11, the light guide mirror group 16, the light splitting mirror group 12, the converging lens group 14 and the second sensor 15 can form a near-infrared light path structure, and the light guide mirror group 16 can be a common light path mirror group for visible light and near-infrared light. The focal length of the visible light path structure can be 20mm-30mm, and the focal length of the near-infrared light path structure can be 13mm-18mm.

[0085] Alternatively, as shown in Figure 11 , the first lens 141 is a double convex lens, the second lens 142 is a concave-convex lens, the convex surface of the first lens 141 and the concave surface of the second lens 142 are cemented; the third lens 143 is a double convex lens, the fourth lens 144 is a double concave lens, and the third lens 143 and the fourth lens 144 are cemented. The focal length of the cemented first lens 141 and the second lens 142 is 23mm-30mm, and the ratio of focal length to central thickness (f / d) is 6-10, respectively. The focal length of the cemented third lens 143 and the fourth lens 144 is -15mm--25mm, and the ratio of focal length to central thickness (f / d) is -4--6.5, respectively.

[0086] In the embodiment of the present application, the first light entrance surface L1 of the first lens 141 in the converging lens group 14 can be a convex surface, and the first light exit surface L2 of the first lens 141 can also be a convex surface; the second light entrance surface L4 of the second lens 142 can be a concave surface, and the second light exit surface L3 of the second lens 142 can be a convex surface. The third light entrance surface L5 of the third lens 143 can be a convex surface, and the third light exit surface L8 of the third lens 143 can also be a convex surface; the fourth light entrance surface L7 of the fourth lens 144 can be a concave surface, and the fourth light exit surface L8 of the fourth lens 144 can also be a concave surface.

[0087] In the embodiments of the present application, the first lens 141, the second lens 142, the third lens 143 and the fourth lens 144 can all be aspherical lenses. For example, as shown in FIG. 1, the first light-out surface L2 of the first lens 141 can be cemented with the second light-in surface L3 of the second lens 142, and the third light-out surface L6 of the third lens 143 can be cemented with the fourth light-in surface L7 of the fourth lens 144. By using the first lens 141, the second lens 142, the third lens 143 and the fourth lens 144 as aspherical lenses, the aberrations (for example, field curvature, distortion and spherical aberration) of the endoscope imaging system 10 can be corrected, so that the imaging quality of the endoscope imaging system 10 is better. Figure 11

[0088] It should be noted that the aspherical lens has the following characteristics: from the center of the lens to the periphery of the lens, the curvature is continuously changed, which is different from the spherical lens with constant curvature from the center of the lens to the periphery of the lens. The aspherical lens has better curvature radius characteristics, and has the advantages of improving the distortion aberration and improving the astigmatism aberration. After using the aspherical lens, the aberrations that occur during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0089] The first lens 141, the second lens 142, the third lens 143 and the fourth lens 144 can also be spherical lenses. The spherical lens has lower manufacturing difficulty, and can reduce the manufacturing difficulty of the endoscope imaging system 10.

[0090] Figure 12 is another modulation transfer function curve diagram of the near-infrared light path provided by the embodiments of the present application, Figure 13 is Figure 12 part of the modulation function curve diagram shown in FIG. 6, please refer to Figure 12 and Figure 13 . Wherein, the abscissa is used to represent the spatial frequency, the unit is line pairs per millimeter, and the ordinate is used to represent the modulation transfer function. The modulation transfer function curve (English: Modulation Transfer Function; abbreviation: MTF) refers to the relationship between the modulation degree and the line pairs per millimeter in the image, which is used to evaluate the ability of the optical element to restore the details of the scene.

[0091] Since the visible light path in the endoscope optical system shown in FIG. 4 is the same as the visible light path in the endoscope optical system shown in FIG. 1, the optical performance of the optical elements between the endoscope light-in port 11 and the first sensor 13 in the endoscope optical system shown in FIG. 4 can refer to the optical performance of the optical elements between the endoscope light-in port 11 and the first sensor 13 in the endoscope optical system shown in FIG. 1. Figure 10 Figure 4 Figure 10 Figure 6 ​​​​The schematic diagram of the modulation transfer function (MTF) curve of the visible light optical path shown indicates that the MTF value of the endoscopic optical system is greater than 0.5 at a spatial frequency of 100 line pairs / mm (lp / mm) and greater than 0.25 at a spatial frequency of 180 line pairs / mm. Therefore, it can be seen that the optical elements in the endoscopic imaging system 10 of this embodiment have good resolution and image-resolving capabilities, and the imaging quality of the visible light optical path structure in the endoscopic imaging system 10 can meet the imaging requirements of endoscopes in this field.

[0092] Figure 12 The modulation transfer function curve in the middle can correspond to Figure 10 The optical performance of the optical elements between the endoscope inlet 11 and the second sensor 15 in the endoscopic optical system shown is as follows: The optical transfer function (MTF) of the endoscopic optical system is greater than 0.5 at a spatial frequency of 100 line pairs / mm and greater than 0.25 at a spatial frequency of 180 line pairs / mm. Therefore, the optical elements in the endoscopic imaging system 10 have good resolution and image-resolving capabilities, and the imaging quality of the visible light path structure in the endoscopic imaging system 10 meets the imaging requirements of endoscopes in this field. Figure 12 It can be seen that the converging lens group, which includes four lenses, can achieve better imaging results in the near-infrared optical path compared to the converging lens group, which includes two lenses.

[0093] When testing the endoscopic imaging system 10, MTF curves corresponding to multiple fields of view (multiple image circle sizes) can be obtained. Under each field of view, there are curves in both the meridional (T) and sagittal (S) directions. To more clearly illustrate the extension of the curves in both directions of the endoscopic imaging system in this embodiment, Figure 13 It shows Figure 12 The curves along the meridian T and sagittal S directions, measured at a radius of 2.6000 mm in the image circle, are derived from... Figure 13 It can be seen that in this embodiment, the MTF value difference between the curves corresponding to the meridional (T) and sagittal (S) directions of the endoscopic imaging system 10 is small. The closer the curves are in these two directions, the closer the MTF performance of the endoscopic imaging system 10 at the same location in the meridional and sagittal directions is, meaning that the imaging quality of the endoscopic imaging system 10 in this embodiment is better. The image circle refers to the circular, bright, and clear image area presented on the focal plane after the incident light passes through the endoscopic imaging system 10; it is also called the image size. Figure 12 and Figure 13The values behind T and S are used to represent the radius of the image circle, such as 0.7200mm represents the MTF value measured at the image circle with a radius of 0.7200mm. The total field distortion of the endoscope imaging system 10 in the embodiments of the present application can be less than 1%, and the distortions of the visible light path and the near-infrared light path are equal.

[0094] Figure 14 is another structural schematic diagram of an endoscope imaging system provided by the embodiments of the present application, please refer to Figure 14 . Optionally, the imaging system further comprises a first filter 17 and a second filter 18. The first filter 17 is located between the endoscope light inlet 11 and the light splitting lens group 12, and the first filter 17 is used to transmit the visible light beam and the near-infrared light beam and block light beams other than the visible light beam and the near-infrared light beam. The light emitted by the light source assembly of the endoscope can include three parts: visible light (400nm-700nm), excitation light (770nm-790nm) and near-infrared light (810nm-890nm), and the first filter 17 can be a notch filter, which can filter out the excitation light to prevent the excitation light from interfering with imaging.

[0095] The second filter 18 is located between the light splitting lens group 12 and the second sensor 15, and the second filter 18 is used to transmit the near-infrared light beam and block light beams other than the near-infrared light beam, and can filter out residual visible light and excitation light to improve the image quality of the near-infrared light image sensor.

[0096] As shown in Figure 15 , Figure 15 is another structural schematic diagram of an endoscope imaging system provided by the embodiments of the present application. The endoscope imaging system 10 can further comprise a protective glass 201 and a housing (not shown in the figure), and the protective glass 201 can be located at the endoscope light inlet 11, and the optical elements in the endoscope system can be located in the housing, and the protective glass 201 and the housing can play a sealing protection role for the endoscope imaging system 10.

[0097] Optionally, the endoscope imaging system 10 further comprises an adjusting assembly 19, which can be connected with the housing 202, and the light guide mirror group 16 is installed in the adjusting assembly 19, and the adjusting assembly 19 is used to drive the light guide mirror group 16 to move between the endoscope light inlet 11 and the light splitting lens group 12 in a direction parallel to the optical axis C2 of the light guide mirror group 16. In this way, the position of the light guide mirror group 16 can be adjusted, that is, the light guide mirror group 16 is moved between the protective glass 201 and the light splitting lens group 12 in a direction parallel to the optical axis C2 of the light guide mirror group 16, so as to adjust the focal length of the endoscope imaging system 10, so that the endoscope imaging system 10 can clearly image objects at different object distances, and the problem that the adaptability of the endoscope imaging system 10 is low can be improved.

[0098] AsFigure 16 As shown, Figure 16 This is an exploded structural diagram of a beam splitter assembly provided in an embodiment of this application. The beam splitter assembly 12 includes a beam splitter prism, which is formed by bonding two identical right-angled triangular prisms together. Specifically, the beam splitter assembly 12 includes a first prism 121, a second prism 122, and a beam splitting film 123. The first prism 121 is surrounded by an incident surface, a first plane, and a first emitting surface. The incident surface is used to receive the light beam emitted from the light guide lens assembly 16, and the first emitting surface is used to emit the light beam to the first sensor 13. The second prism 122 is surrounded by a second plane, a third plane, and a second emitting surface. The second emitting surface is used to emit the light beam to the converging lens assembly 14. The first plane of the first prism 121 and the second plane of the second prism 122 are arranged opposite to each other. The beam splitting film 123 is located on the first plane or on the second plane. The beam splitting film 123 can be a dichroic beam splitting film 123, which can transmit visible light beams and reflect near-infrared light beams.

[0099] like Figure 17 As shown, Figure 17 This is a schematic diagram of another endoscopic imaging system 10 provided in this application embodiment. The beam-splitting film in the beam-splitting lens group 12 can transmit near-infrared light beams and reflect visible light beams. Thus, the positions of the first sensor 13 and the second sensor 15 can be flexibly adjusted according to the characteristics of the beam-splitting film in the beam-splitting lens group 12.

[0100] Figure 18 This is a schematic diagram of another endoscopic imaging system 10 provided in this application embodiment. Please refer to it. Figure 18 In an optional embodiment, the beam splitter group 12 may also be a dichroic filter 124, which can transmit visible light beams and reflect near-infrared light beams. The beam splitter group 12 includes a light inlet 12a, a first light outlet 12b, and a second light outlet 12c. The light inlet 12a and the first light outlet 12b may be located on the outer sides of two surfaces of the dichroic filter 124, respectively, and the light inlet 12a and the second light outlet 12c may be located on the outer sides of the same surface of the dichroic filter 124.

[0101] It should be noted that the light inlet 12a of the mirror assembly in this embodiment can be an actual structure, such as... Figure 1 The light-incident surface on the beam splitter shown, or the light-incident port 12a of the lens assembly, can be a virtual light-incident port, such as... Figure 18 The light inlet 12a shown indicates that the light beam is incident on the dichroic filter 124 at the location of the light inlet 12a. Similarly, the first light outlet 12b and the second light outlet 12c can be actual structures or virtual light outlets, and this application embodiment does not limit them.

[0102] In conclusion, the embodiment of the present application provides an endoscope imaging system, comprising an endoscope light inlet, a beam splitter, a first sensor, a converging lens group and a second sensor. The beam splitter is used to divide the received light beam into a first light beam and a second light beam, wherein the wavelength of the first light beam is smaller than that of the second light beam, and the first light beam and the second light beam are guided to the first sensor and the converging lens group respectively. The converging lens group transmits the converged second light beam to the second sensor. In this way, the energy per unit area of the light spot received by the light receiving surface of the second sensor can be improved, the definition of the image formed by the second sensor can be improved, and the registration accuracy of the images formed by the two image sensors can be improved. The problem of low registration accuracy of the images formed by the two image sensors in the related art is solved, and the effect of improving the registration accuracy of the images formed by the two image sensors in the endoscope imaging system is achieved.

[0103] In addition, the embodiment of the present application also provides an endoscope, which comprises the endoscope imaging system in any of the above embodiments.

[0104] In the present application, the terms "first", "second", "third" and "fourth" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. The term "a plurality of" means two or more, unless otherwise explicitly limited.

[0105] The above is only an optional embodiment of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An endoscopic imaging system, characterized by, The endoscope imaging system comprises an endoscope light inlet, a light guide lens group, a light splitting lens group, a first sensor, a converging lens group and a second sensor; The light splitting lens group is located on one side of the endoscope light inlet, and comprises a lens group light inlet, a first light outlet and a second light outlet. The light splitting lens group is configured to receive a light beam incident from the endoscope light inlet through the lens group light inlet, and split the received light beam into a first light beam and a second light beam. The first light beam is emitted from the light splitting lens group through the first light outlet, and the second light beam is emitted from the light splitting lens group through the second light outlet. The wavelength of the first light beam is smaller than that of the second light beam. The first sensor is located outside the first light outlet, and the converging lens group and the second sensor are arranged in sequence in a direction away from the second light outlet. The energy of the second light beam is smaller than that of the first light beam. The first light beam is a visible light beam, and the second light beam is a near-infrared light beam. The first sensor is a visible light image sensor, and the second sensor is a near-infrared light image sensor. The light guide lens group is located between the endoscope light inlet and the light splitting lens group, and is configured to receive a light beam incident from the endoscope light inlet and guide the light beam to the light splitting lens group. The endoscope light inlet, the light guide lens group, the light splitting lens group and the first sensor form a visible light path structure, and the endoscope light inlet, the light guide lens group, the light splitting lens group, the converging lens group and the second sensor form a near-infrared light path structure. The area of the visible light image obtained by the first sensor is larger than the area of the near-infrared light image obtained by the second sensor.

2. The endoscopic imaging system of claim 1, wherein, The converging lens group comprises a first lens and a second lens. The first lens is located on a side of the second lens away from the second sensor. The first lens has a positive focal power, and the second lens has a negative focal power. The first lens and the second lens share an optical axis.

3. The endoscopic imaging system of claim 2, wherein, The first lens is a double convex lens, and the second lens is a double concave lens. The first lens and the second lens are cemented.

4. The endoscopic imaging system of claim 3, wherein, The first lens has a first light inlet surface and a first light outlet surface. The ratio of the curvature radius value of the first light inlet surface to the curvature radius value of the first light outlet surface ranges from 0.6 to 1. The ratio of the Abbe number to the refractive index of the material of the first lens ranges from 26 to 32. The second lens has a second light inlet surface and a second light outlet surface. The ratio of the curvature radius value of the second light inlet surface to the curvature radius value of the second light outlet surface ranges from 0.45 to 1. The ratio of the Abbe number to the refractive index of the material of the second lens ranges from 14 to 20.

5. The endoscopic imaging system of claim 2, wherein, The converging lens group further comprises a third lens and a fourth lens located between the second lens and the second sensor. The third lens and the fourth lens are arranged in sequence in a direction away from the second lens. The third lens has a positive focal power, and the fourth lens has a negative focal power. The first lens, the second lens, the third lens and the fourth lens share an optical axis.

6. The endoscopic imaging system of claim 5, wherein, The first lens is a double convex lens, the second lens is a meniscus lens, the convex surface of the first lens and the concave surface of the second lens are cemented together; The third lens is a double convex lens, the fourth lens is a double concave lens, the third lens and the fourth lens are cemented together.

7. The endoscopic imaging system of claim 1, wherein, The imaging system further comprises a first filter and a second filter; The first filter is located between the endoscope entrance and the beam splitter, the first filter is used to transmit the visible light beam and the near-infrared light beam, and to block light beams other than the visible light beam and the near-infrared light beam; The second filter is located between the beam splitter and the second sensor, the second filter is used to transmit the near-infrared light beam, and to block light beams other than the near-infrared light beam.

8. The endoscopic imaging system of claim 1, wherein, The imaging system further comprises an adjusting assembly, the light guide lens group is installed in the adjusting assembly, the adjusting assembly is used to drive the light guide lens group to move between the endoscope entrance and the beam splitter along a direction parallel to the optical axis of the light guide lens group.

9. An endoscope characterized by comprising: The endoscope comprises the endoscope imaging system of any one of claims 1-8.

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