CN111474694A - Large-view-field miniature endoscope - Google Patents

Abstract

The invention relates to the technical field of medical diagnosis imaging equipment, in particular to a large-view-field miniature endoscope which comprises a miniature probe, wherein the miniature probe comprises a shell, an objective lens fixed with the shell and a scanner arranged in the shell, a back focal plane calculated by the objective lens according to the wavelength of exciting light is positioned outside the objective lens body, and the scanner is positioned at the back focal plane of the objective lens. The back focal plane of this scheme objective is located outside the mirror body to set up the scanner through the back focal plane at objective, under the unchangeable prerequisite of keeping incident beam diameter, increase angle of vision reduces the volume of the miniature probe of endoscope, has solved among the prior art and has caused objective and the problem that miniature probe volume increases for realizing big visual field.

Description

A large field of view miniature endoscope

technical field

The invention relates to the technical field of medical diagnostic imaging equipment, in particular to a large field of view miniature endoscope.

Background technique

With the development of science and technology, medical endoscope has been widely used in the medical field. It is one of the important tools for humans to peep and treat the internal organs of the human body. In the course of more than 200 years of development, the structure of endoscope has undergone four major improvements, from the initial rigid endoscope, semi-curved endoscope to fiber endoscope, to today's electronic endoscope, Image quality has also undergone a sub-quality leap. Using LED lighting today, endoscopes can obtain color photos or color TV images. At the same time, the images are no longer ordinary images of tissues and organs, but microscopic images like those observed under a microscope, and tiny lesions can be clearly identified. According to the existing clinical experience, the smaller the volume of the micro-probe of the endoscope, the shorter the rigid segment, which can minimize the pain of the patient, so the endoscope has been developing towards miniaturization. Current endoscopes have large magnifications, resulting in a small field of view.

With the development of medical diagnosis in recent years, the narrow field of view of traditional endoscope cannot meet the needs of current medical diagnosis. At present, there is a design in the United Kingdom and the United States that achieves a large field of view, and both designs have been commercialized. Both designs rely on greatly increasing the diameter of the incident beam to bring about a large field of view and a large amount of light. However, these two designs Such a design will cause the objective lens of the endoscope micro-probe to be very expensive and bulky, which does not conform to the development trend of endoscopes.

SUMMARY OF THE INVENTION

The present invention aims to provide a large field of view miniature endoscope. On the premise of keeping the diameter of the incident beam unchanged, the field of view angle is increased, and the volume of the endoscope microprobe is reduced. The field of view causes the problem of increasing the volume of the objective lens and the micro-probe.

The scheme is basically as follows: a large field of view miniature endoscope, including a miniature probe, the miniature probe includes a casing, an objective lens fixed with the casing, and a scanner arranged in the casing, the back focal plane of the objective lens calculated according to the wavelength of the excitation light is located at Outside of the objective body, the scanner is located at the back focal plane of the objective.

Beneficial effects: Compared with the objective lens (scan lens), the present invention has ultra-short focal length, high numerical aperture and smaller field of view. This solution has a large field of view and an external rear focal plane, because this solution is very different from ordinary scanning lenses and ordinary microscope objective lenses, and is unique. In use, when using a single uniaxial scanner or a single biaxial scanner, the single uniaxial scanner or a single biaxial scanner is located in the back focal plane of the objective; use a set of two uniaxial scanners , the back focal plane of the objective is in the middle of a set of two uniaxial scanners. Since the back focal plane of the present invention is far away from the mirror body (usually a few millimeters away), there is enough space to install the scanner without the need for a scanning lens and a tube lens (as in conventional laser scanning endoscopes) between the scanner and the objective lens ( tube lens), the length of the scanning and imaging optical path of the microscope is greatly shortened, the present invention is used to focus the excitation beam reflected by the scanner in the sample, and collect the emitted light signal excited in the sample, which is coupled into the sample for transmission through the focusing lens Optical fibers for optical signals or photodetectors for detecting optical signals.

Further, the scanner adopts a dichroic mirror scanner, and the dichroic mirror scanner includes a driver and several dichroic mirrors, and the dichroic mirrors are used to reflect laser light and allow nonlinear optical signals to pass through; the driver For changing the angle of the dichroic mirror according to the instruction, the driver includes several mirror bodies through which the nonlinear optical signal can transmit, and the dichroic mirror is fixed on the surface of the mirror body.

Compared with traditional scanners such as MEMS in the prior art, the two-way scanner can meet the imaging quality without scanning lens and tube lens, reduce the number of lenses in the housing, reduce the volume of the micro probe, and greatly reduce the size of the micro-probe. Improved imaging speed.

Further, the dichroic mirror includes an ultra-thin sheet, and the ultra-thin sheet is coated with a dichroic film.

The dichroic mirror obtained in this way can be thinner and lighter, which is beneficial to further reduce the size and weight of the micro-probe.

Further, the objective lens comprises a lens 1, a lens 2, a lens 3, a lens 4 and a lens 5 through which the outgoing light rays pass in turn, the lens 1 is a concave-convex lens, the lens 2 is a biconvex lens, the lens 3 is a convex-concave lens, and the lens 4 is a convex-concave lens The lens, the fifth lens is a biconvex lens. In this combination, the objective lens can be such that the focal plane is located outside the mirror body.

Further, the curvature radii of the first lens relative to the image side surface S11 and the relative object side surface S12 are -5.422mm and -15.096mm respectively; the curvature radii of the second lens relative to the image side surface S21 and the relative object side surface S22 are respectively 40.057mm and -119.509mm; the curvature radii of the lens three relative to the image side surface S31 and the relative object side surface S32 are 18.574mm and 39.689mm respectively; the curvature of the lens four relative to the image side surface S41 and the opposite object side surface S42 The radii are 6.873mm and 8.074mm respectively; the radii of curvature of the four lens surfaces opposite the image side surface S51 and the opposite object side surface S52 are 103.816mm and -26.042mm respectively.

The opposite image side surface is the surface where the lens is farther from the scanning object, and the opposite object side surface is the surface where the lens is closer to the scanning object. The surface curvature of each lens is set according to the above parameters. Under the premise of ensuring a large field of view, the volume of the objective lens is relatively small.

Further, the thickness of the S11 is 14.307mm, the thickness of the S12 is 0.2mm, the thickness of the S21 is 1.5mm, the thickness of the S22 is 0.2mm, the thickness of the S31 is 1.674mm, the thickness of the S32 is 0.2mm, and the thickness of the S41 is 6.083mm, the thickness of the S42 is 0.75mm, the thickness of the S51 is 6.083mm, and the thickness of the S52 is 0.75mm.

Each lens is set with the above parameters, and under the premise of ensuring a large field of view, the axial length of the objective lens is short.

Further, the radius of S11 is 6mm, the radius of S12 is 14mm, the radius of S21 is 14mm, the radius of S22 is 14mm, the radius of S31 is 14mm, the radius of S32 is 14mm, the radius of S41 is 12mm, and the radius of S42 is 6.6mm, the S51 has a 7.2mm radius, and the S52 has a 7.2mm radius.

In this way, when the objective lens satisfies a large field of view, the cross-sectional area of the objective lens composed of the radii of the above-mentioned surfaces is small.

Further, the materials of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all optical glass or high molecular polymer or infrared imaging material. Optical glass or high molecular polymer or infrared imaging material are commonly used materials for lenses in the field.

Further, the numerical aperture of the objective lens is greater than or equal to 0.7.

Further, the field angle of the objective lens is greater than or equal to 15 degrees.

Description of drawings

FIG. 1 is a schematic structural diagram of a micro-probe of the present invention.

FIG. 2 is a schematic diagram of an optical structure of an objective lens according to an embodiment of the present invention.

FIG. 3 is a field curvature and distortion diagram of excitation light wavelengths according to an embodiment of the present invention.

FIG. 4 is a vignetting diagram of a focal plane of excitation light wavelengths according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of a scanner according to an embodiment of the present invention.

Detailed ways

The following is further described in detail by specific embodiments:

The reference signs in the drawings include: lens one 1, lens two 2, lens three 3, lens four 4, lens five 5, scanner 6, laser input fiber 90, laser output fiber 91, driver 22, dichroic Mirror 33 , micro probe 50 .

The embodiment is basically as follows:

A large field of view miniature endoscope, as shown in Figure 1, includes a miniature probe 50, the miniature probe 50 includes a casing and an objective lens, the casing is a sealing structure made of high molecular polymer material, and a scanner 6 and a plurality of scanners are arranged inside the casing. The upper end of the casing is connected with a laser input optical fiber 90 and a laser output optical fiber 91, the objective lens is fixed on the lower end of the casing, that is, the front aperture, and the scanner 6 is located above the objective lens. The scanner 6 is rotatably connected with the housing, so that the scanner 6 can change the angle to scan. The laser light emitted by the output fiber is reflected by the dichroic mirror and then emitted from the objective lens to irradiate the human tissue.

As shown in FIG. 2 , the objective lens includes lens one 1, lens two 2, lens three 3, lens four 4 and lens five 5, and the scanner 6 is located on the back focal plane calculated by the objective lens according to the wavelength of the excitation light. The lens 11 is a concave-convex lens, the lens 22 is a biconvex lens, the lens 33 is a convex-concave lens, the lens 44 is a convex-concave lens, and the lens 55 is a biconvex lens.

Lens one 1 has a surface S11 opposite to the image side and a surface S12 opposite to the object side, lens two 2 has a surface S21 opposite the image side and a surface S22 opposite the object side, and lens three 3 has a surface S31 opposite the image side and the opposite object side The lens four 4 has a surface S41 opposite the image side and a surface S42 opposite the object side, and the lens five 5 has a surface S51 opposite the image side and a surface S52 opposite the object side.

The material of lens one 1, lens two 2, lens three 3, lens four 4 and lens five 5 is optical glass or high molecular polymer or infrared imaging material.

The data of each lens surface satisfies the following table:

The excitation light wavelength is 920 nanometers, and the emission light wavelength is 520 nanometers.

The numerical aperture of the objective lens is 0.7, the working distance is 1 mm, and the diameter of the field of view is 1.65 mm.

This embodiment is used for nonlinear optical imaging, so the requirement for achromatic aberration is not high.

FIG. 2 shows the field curvature and distortion diagram of the excitation light wavelength of this embodiment. Since this embodiment is used for imaging of living biological tissue, the requirements for the distortion of the field curvature are not high.

Fig. 3 shows the vignetting diagram of the excitation light focal plane of this embodiment, and the excitation light wavelength reaches a transmission efficiency greater than 0.5 at the maximum viewing angle.

As shown in FIG. 5 , the scanner 6 adopts a dichroic mirror scanner. The dichroic mirror scanner includes a driver 22 and a plurality of dichroic mirrors 33, which are used to reflect laser light and provide nonlinear The optical signal passes through; the driver 22 is used to change the angle of the dichroic mirror 33 according to the instruction. The driver 22 includes several mirror bodies for the nonlinear optical signal to pass through. The dichroic mirror 33 is fixed on the surface of the mirror body.

The dichroic mirror 33 includes an ultra-thin sheet, and the ultra-thin sheet is coated with a dichroic film. The dichroic mirror 33 can reflect the laser light incident on the laser incident optical fiber 90, and can transmit the emitted light (such as fluorescent photons) excited by human tissue. Compared with the conventional MEMS scanner 6 in the prior art, the bidirectional scanner 6 can satisfy the imaging quality without scanning lens and tube lens, reduce the number of lenses in the housing, and reduce the volume of the micro-probe 50 , while greatly improving the imaging speed.

The above are only the embodiments of the present invention, and common knowledge such as well-known specific structures and characteristics in the solution are not described too much here. It should be pointed out that for those skilled in the art, some modifications and improvements can be made without departing from the structure of the present invention. These should also be regarded as the protection scope of the present invention, and these will not affect the implementation of the present invention. Effectiveness and utility of patents. The scope of protection claimed in this application should be based on the content of the claims, and the descriptions of the specific implementation manners in the description can be used to interpret the content of the claims.

Claims (10)

1. The utility model provides a miniature endoscope of big visual field, includes miniature probe, miniature probe include the shell, with the fixed objective of shell and locate the scanner in the shell, its characterized in that: the back focal plane calculated by the objective lens according to the wavelength of the exciting light is positioned outside the objective lens body, and the scanner is positioned at the back focal plane of the objective lens.

2. The large field of view miniature endoscope according to claim 1, characterized in that: the scanner adopts a dichroic mirror scanner, the dichroic mirror scanner comprises a driver and a plurality of dichroic mirrors, and the dichroic mirrors are used for reflecting laser and allowing nonlinear optical signals to pass through; the driver is used for changing the angle of the dichroic mirror according to the instruction, the driver comprises a plurality of mirror bodies for transmitting the nonlinear optical signals, and the dichroic mirror is fixed on the surface of the mirror bodies.

3. The large field of view miniature endoscope according to claim 2, characterized in that: the dichroic mirror comprises an ultrathin sheet, and a dichroic film is plated on the ultrathin sheet.

4. A large field of view miniature endoscope according to claim 3, characterized in that: the objective lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, wherein emergent rays sequentially pass through the first lens, the second lens, the third lens, the fourth lens and the fifth lens, the first lens is a concave-convex lens, the second lens is a double-convex lens, the third lens is a concave-convex lens, the fourth lens is a concave-convex lens, and the fifth lens is a double-convex lens.

5. The large field of view miniature endoscope according to claim 4, characterized in that: the curvature radii of an opposite image side surface S11 and an opposite object side surface S12 of the lens are-5.422 mm and-15.096 mm, respectively; the radii of curvature of the two opposite object side surfaces S21 and S22 of the lens are 40.057mm and-119.509 mm, respectively; the radii of curvature of the three opposite object side surface S31 and the opposite object side surface S32 of the lens are 18.574mm and 39.689mm, respectively; the curvature radii of the four opposite object side surfaces S41 and S42 of the lens are 6.873mm and 8.074mm respectively; the radii of curvature of the four opposite object side surfaces S51 and the opposite object side surface S52 of the lens are 103.816mm and-26.042 mm, respectively.

6. The large field of view miniature endoscope according to claim 5, characterized in that: the thickness of S11 is 14.307mm, the thickness of S12 is 0.2mm, the thickness of S21 is 1.5mm, the thickness of S22 is 0.2mm, the thickness of S31 is 1.674mm, the thickness of S32 is 0.2mm, the thickness of S41 is 6.083mm, the thickness of S42 is 0.75mm, the thickness of S51 is 6.083mm, and the thickness of S52 is 0.75 mm.

7. The large field of view miniature endoscope according to claim 6, characterized in that: the radius of S11 is 6mm, the radius of S12 is 14mm, the radius of S21 is 14mm, the radius of S22 is 14mm, the radius of S31 is 14mm, the radius of S32 is 14mm, the radius of S41 is 12mm, the radius of S42 is 6.6mm, the radius of S51 is 7.2mm, and the radius of S52 is 7.2 mm.

8. A large field of view miniature endoscope according to any of claims 2-7, characterized in that: the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all made of optical glass or high molecular polymer or infrared imaging materials.

9. The large field of view miniature endoscope according to claim 8, characterized in that: the numerical aperture of the objective lens is greater than or equal to 0.7.

10. The large field of view miniature endoscope according to claim 8, characterized in that: the field angle of the objective lens is equal to or larger than 15 degrees.

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