CN112925092B - Electronic hysteroscope imaging lens for gas and liquid uterus expansion - Google Patents

Abstract

The invention discloses an electronic hysteroscope imaging lens for gas and liquid dilatation of the uterus. Six lenses, a diaphragm is placed between the second lens and the third lens, the fourth lens and the fifth lens form a doublet, and the image plane is placed outside the sixth lens. The lens of the invention has a small aperture, can obviously relieve the pain of patients, and is suitable for the early diagnosis of uterine cancer; the structure is simple, the operation is convenient, and multi-scene application requirements can be achieved only by adjusting the interval of the lens groups; it can realize a 90° field of view without blind spots and a large depth of field , High-resolution imaging, improve the detection rate and diagnosis rate of early diseases, especially tumors, reduce unnecessary operations by doctors on internal instruments, and reduce the risk of surgery.

Description

An electronic hysteroscope imaging lens for gas and liquid dilatation of the uterus

technical field

The invention relates to the field of optical technology, in particular to an electronic hysteroscope imaging lens for gas and liquid dilatation of the uterus, which is used for uterine cavity imaging in gynecological minimally invasive surgery and hysteroscope-free anesthesia inspection.

Background technique

With the gradual improvement of living standards, people pay more and more attention to their own health. Cervical cancer is the second most common cancer among women in the world. It takes more than ten years for cervical cells to mutate into cancer cells. If the disease can be detected and treated in time at the early stage, the cure rate can reach 100%. At present, in clinical medicine, the diagnosis methods of uterine diseases mainly include ultrasound technology and medical endoscope. Traditional ultrasound technology can only observe the cross-sectional structure of the organ, which has the disadvantages of not direct image and small field of view. However, endoscopy is used in the medical field. It has a history of nearly a hundred years. Since the invention of the rigid endoscope by the Germans in 1806, it has experienced the development process of the rigid endoscope, the fiber optic endoscope and the electronic endoscope. Low, limited observation angle, low image resolution, and pain to patients during inspection, limit its application in the early diagnosis of uterine cancer; electronic endoscope is an extension of the doctor's vision, and is used in hysteroscopy The ultra-fine optical fiber brings tiny "electronic eyes" from the vagina and cervix into the uterine cavity, which can directly display the tissue morphology of the surface of internal organs and the lesions in the body through the endoscope without opening the cavity or minimally invasive, assisting doctors in uterine cavity diseases. Diagnosis and treatment can significantly reduce the suffering of patients, such as the early diagnosis of uterine cancer and the diagnosis and treatment of uterine malformations, endometrial polyps, uterine foreign bodies, abnormal uterine bleeding and other diseases, but the electronic endoscopes in the existing technology still have the following: shortcoming:

(1) The hard tube endoscope commonly used in clinical uterine cavity detection in China has blind spots, low image resolution, and pain to the patient during inspection. The glass fiber in the fiber optic endoscope is easy to break, resulting in black spots on the imaging. In addition to low image resolution, traditional B-ultrasound technology also has the problem of indirect images, which limit their widespread clinical use.

(2) Due to the high price of anesthesia-free electronic hysteroscopes, many rely on imports, which increases the medical cost and capital investment of hospitals. The outer diameter of the hard part of many domestic hysteroscopic imaging lenses exceeds the upper limit of 8mm allowed for the diagnosis of uterine cavity without anesthesia. Anesthesia is required for diagnosis, and it is only suitable for surgical conditions, not for early diagnosis of uterine cancer, which limits its application range.

(3) In order to clearly observe the structure of the uterine cavity, the uterine cavity needs to be distended during the examination. Different hysteroscopic imaging lenses should be used for different methods of uterine distention, such as gas and liquid uterine distention, which increases the hospital’s capital investment. ; Since the uterine lens is in the air when processing and assembling, it is difficult to detect the quality of the uterine mirror in real time during the production and processing stage when the state of liquid distended uterus is detected.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an anesthesia-free, large depth of field, and no blind spot electronic hysteroscope imaging lens suitable for gas or liquid uterine distention.

In order to realize the above-mentioned purpose of the invention, the present invention adopts the following technical solutions:

An electronic hysteroscope imaging lens for gas and liquid dilatation of the uterus, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object to the image. A diaphragm is placed between the second lens and the third lens, the fourth lens and the fifth lens form a doublet, and the image plane is placed outside the sixth lens.

The curvature radii of the front and rear surfaces of the first lens are all positive values, the front surface is a low-order aspheric surface, and the rear surface is a high-order aspheric surface.

The curvature radii of the front and rear surfaces of the second lens are all positive values, the front surface is a high-order aspheric surface, and the rear surface is a low-order aspheric surface.

The curvature radius of the front surface of the third lens is a positive value, the curvature radius of the rear surface is a negative value, the front surface is a high-order aspheric surface, and the rear surface is a low-order aspheric surface.

The curvature radii of the front and rear surfaces of the fourth lens are all positive values, the front surface is a low-order aspheric surface, and the rear surface is a standard spherical surface.

The curvature radius of the front surface of the fifth lens is a positive value, the curvature radius of the rear surface is a negative value, the front surface is a standard spherical surface, and the rear surface is a high-order aspherical surface.

The curvature radii of the front and rear surfaces of the sixth lens are all negative values, the front surface is a low-order aspheric surface, and the rear surface is a high-order aspheric surface. The optical power of the optical train composed of the first lens and the second lens is a negative value.

The optical power group composed of the third lens, the fourth lens, the fifth lens and the sixth lens is a positive value.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The diameter of the imaging lens of the electronic hysteroscope is limited to within 3.2mm, which meets the needs for the diagnosis of intrauterine lesions without anesthesia, can significantly reduce the pain of patients during examination, and is suitable for the early diagnosis of uterine cancer;

(2) Different application requirements can be achieved only by adjusting the interval of the lens groups, such as hysteroscopy in gas and liquid dilatation; in the production and assembly stage, the quality of the air-medium uterine mirror is detected, and it is also in the actual diagnosis and treatment stage. The quality detection of hysteroscopic imaging system provides an important basis for the detection of fluid distended uterus;

(3) It can realize high-resolution imaging with 90° field of view without blind area and large depth of field, which can not only observe the full field of view image, but also obtain the details of the lesion area, and realize the low-distortion and high-definition image enlargement of the lesion in the local area. Excellent, improve the detection rate and diagnosis rate of early-stage diseases, especially tumors, and the imaging characteristics of no blind spot allow the hysteroscope to be in a fixed position for full-field observation, reducing unnecessary operations by doctors on internal instruments and reducing surgical risks. .

Description of drawings

Figure 1 is a schematic diagram of the structure of an electronic hysteroscope imaging lens (object distance 100mm);

Figure 2 is the RayFan curve and the field curvature and distortion images of the electronic hysteroscopy imaging system in the state of liquid distended uterus (object distance 100mm), of which Figure 2(2a) is the RayFan curve, and Figure 2(2b) is the field curvature and distortion images;

Figure 3 is the RayFan curve and the field curvature and distortion images of the electronic hysteroscopy imaging system in the state of gas distended uterus (object distance 100mm), of which Figure 3(3a) is the RayFan curve, and Figure 3(3b) is the field curvature and distortion images;

Figure 4 is the relative illumination diagram of the electronic hysteroscopy imaging system (object distance 100mm), in which Figure 4 (4a) is the state of liquid distended uterus, and Figure 4 (4b) is the state of gas distended uterus;

Figures 5-7 are the transfer function curves and point diagrams of the electronic hysteroscopy imaging system of the gas distended uterus when the object distances are 80mm, 100mm and 120mm, respectively. Figures 5(5a), 6(6a) and 7(7a) ) is the transfer curve, and Figure 5(5b), Figure 6(6b), and Figure 7(7b) are point diagrams;

Figures 8-10 are the transfer function curves and point diagrams of the electronic hysteroscopy imaging system for the liquid uterine distended state when the object distances are 80mm, 100mm and 120mm, respectively. Figures 8(8a), 9(9a) and 10(10a) ) is the transfer curve, and Figure 8 (8b), Figure 9 (9b), and Figure 10 (10b) are point diagrams.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the accompanying drawings.

The electronic hysteroscope imaging lens of the present invention selects a five-piece negative focal power in the front and a "reverse telephoto" lens group with a positive focal power in the back as the initial structure, which can take into account a large field of view and a large relative aperture. Compared with the double Gaussian structure, the image surface illumination is relatively uniform.

As shown in FIG. 1, the electronic hysteroscope imaging lens of the present invention includes a first lens 1, a second lens 2, a third lens 4, a fourth lens 5, a fifth lens 6 and The sixth lens 7, the diaphragm 3 is placed between the second lens 2 and the third lens 4, the fourth lens 5 and the fifth lens 6 form a doublet lens, and the image plane 8 is placed after the sixth lens 7. The curvature radii of the front and rear surfaces of the first lens 1 are all positive values, the front surface is a low-order aspheric surface, the rear surface is a high-order aspheric surface, and the curvature radii of the front and rear surfaces of the second lens 2 are all positive values, and the front surface is a high-order aspheric surface Aspheric surface, the rear surface is a low-order aspheric surface, the curvature radius of the front surface of the third lens 4 is a positive value, and the curvature radius of the rear surface is a negative value, the front surface is a high-order aspheric surface, and the rear surface is a low-order aspheric surface. The curvature radii of the front and rear surfaces of the four lenses 5 are all positive values, the front surface is a low-order aspheric surface, the rear surface is a standard spherical surface, the curvature radius of the front surface of the fifth lens 6 is positive, the The surface is a standard spherical surface, the rear surface is a high-order aspheric surface, the curvature radii of the front and rear surfaces of the sixth lens 7 are negative values, the front surface is a low-order aspheric surface, and the rear surface is a high-order aspheric surface. The optical power of the optical group composed of the first lens 1 and the second lens 2 is negative; the optical power of the optical group composed of the third lens 4, the fourth lens 5, the fifth lens 6 and the sixth lens 7 is positive value.

In order to improve the fineness of the target observation, the endoscope is required to have a large depth of field and high resolution. If the resolution is poor, the characteristics of the tissue in the body and the details of the lesion area cannot be obtained, and the significance of clinical diagnosis will be lost; if the depth of field is too small, the clear range of imaging will be insufficient, and the blurred field of view will easily lead to misdiagnosis. The larger the resolution, the smaller the depth of field; in order to improve the system resolution, simply increasing the diameter of the entrance pupil will easily lead to image quality degradation, and the larger the diameter of the entrance pupil, the smaller the depth of field, so the diameter of the entrance pupil cannot be unlimited. Increase, preferably, the diameter of the entrance pupil of the system is increased to D=0.35mm, and the object distance needs to be set to multiple structures for optimization during design, taking into account the influence of the system working distance on the depth of field, preferably, the depth of field range is controlled at 80～ between 120mm.

In order to obtain a larger observation range under a limited aperture, preferably, the field of view angle is set to 90°. If the imaging has serious large field of view aberrations such as distortion, field curvature and astigmatism, the distortion will affect the doctor's accurate judgment of the lesion location. The field curvature or astigmatism will cause the doctor's observation field to be unclear and easily lead to misdiagnosis. The weight of the poor field of view is adjusted in time to control the field curvature and astigmatism within the allowable tolerance range; the imaging characteristics of low distortion and no blind spot allow the hysteroscope to be in a fixed position for full field of view observation, reducing the doctor's attention to the body. The unnecessary operation of the instrument can accurately determine the location of the lesion, thereby reducing the risk of surgery, which is of great significance for improving work efficiency and increasing the amount of acquired image information.

At the same time, the introduction of aspheric surface can simplify the structure, reduce light energy loss, improve image quality and image surface illumination, and also realize the miniaturization of the lens group and control the outer diameter of the lens group within 3.2mm, which is suitable for the needs of anesthesia-free uterine cavity examination. However, the use of aspheric surfaces will increase the cost of component manufacturing and testing. It is necessary to strictly control the number of aspheric surfaces of the hysteroscope. Considering the system packaging requirements when using the hysteroscope in a liquid distended state, try to avoid using high-order aspheric surfaces on the first side.

Since the hysteroscope needs to work in two working states of gas distention and liquid distention, the glass material between the object surface and the first surface of the lens needs to be set to multiple structures for optimization. This design scheme also greatly facilitates production and processing. Mirror quality detection of uterine cavity in the state of liquid distended uterus after encapsulation of stage and imaging lens.

As shown in Table 1 and Table 2, considering the system packaging requirements, the use of a high-order aspheric surface on the first surface of the lens group is avoided. Since the structural parameters of the gas dilatation lens and the liquid dilatation lens are the same, it is only necessary to adjust the interval of each lens group. It is used in two different working states of gas distention and liquid distention, which saves costs. It can detect the mirror quality of the air medium uterus in the production and assembly stage, and also provide the image quality detection of the hysteroscopic imaging system in the state of liquid distention. important basis.

Table 1 Electronic hysteroscopy imaging lens LensDataEditor

Table 2 Multiple structural data of the imaging lens of electronic hysteroscopy

The electronic hysteroscope imaging lens of the present invention has a maximum field of view angle of 90° and a working depth of field of 80-120 mm. Preferably, the diameter of the imaging lens is within 3.2 mm, and the distance from the first surface of the imaging system to the image surface is 6.5 mm. Within the scope, it can meet the needs of no anesthesia, no blind spot, and large depth of field diagnosis of the uterine cavity.

The spatial resolution and field of view of the electronic hysteroscope imaging lens of the present invention both meet the requirements of a 1/6-inch CCD. As shown in Table 1, the maximum diameter of the image formed by the electronic hysteroscope on the image plane 8 is 2.999mm. When the 1/6-inch CCD image sensor is placed on the image plane 8 of the optical system, the formed image should be externally connected to 1/6 inch CCD. As shown in Figure 5-10, in the two working states of gas distention and liquid distention, the optical modulation transfer function MTF>0.4 at the spatial resolution of the optical system of 100lp/mm, which meets the requirements of 1/6-inch CCD spatial resolution. The RMS radius and GEO radius of the full-field spot diagram in the two working states of gas distention and liquid distention are both smaller than the system diffraction Airy disk radius, which can achieve high-definition imaging.

Claims (3)

1. An electronic hysteroscope imaging lens for gas and liquid dilatation of the uterus, comprising a lens, wherein the lens comprises a first lens (1) and a second lens (2) arranged in sequence from the object to the image , the third lens (4), the fourth lens (5), the fifth lens (6) and the sixth lens (7), and the diaphragm (3) is placed between the second lens (2) and the third lens (4) , the fourth lens (5) and the fifth lens (6) form a doublet lens, and the image plane (8) is placed on the rear side of the sixth lens (7). Negative, positive, positive, negative, positive, and positive, respectively, the curvature radii of the front and rear surfaces of the first lens (1) are all positive values, the front surface is a low-order aspheric surface, and the rear surface is a high-order aspheric surface. The curvature radii of the front and rear surfaces of the second lens (2) are all positive values, the front surface is a high-order aspheric surface, and the rear surface is a low-order aspheric surface; the curvature radius of the front surface of the third lens (4) is a positive value, The curvature radius of the surface is a negative value, the front surface is a high-order aspheric surface, and the rear surface is a low-order aspheric surface; the curvature radii of the front and rear surfaces of the fourth lens (5) are positive values, and the front surface is a low-order aspheric surface, The rear surface is a standard spherical surface; the curvature radius of the front surface of the fifth lens (6) is a positive value, the curvature radius of the rear surface is a negative value, the front surface is a standard spherical surface, and the rear surface is a high-order aspheric surface; the sixth lens (6) has a high-order aspheric surface. The curvature radii of the front and rear surfaces of the lens (7) are all negative values, the front surface is a low-order aspheric surface, and the rear surface is a high-order aspheric surface. 2 . The electronic hysteroscope imaging lens according to claim 1 , wherein the optical power of the optical train group composed of the first lens ( 1 ) and the second lens ( 2 ) is a negative value. 3 . 3. The electronic hysteroscope imaging lens according to claim 1, wherein the third lens (4), the fourth lens (5), the fifth lens (6) and the sixth lens (7) are composed of The optical power of the optical group is a positive value.

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