A medical endoscope optical zoom 4K adapter

Abstract

The present invention is a 4K optical zoom adapter for medical endoscopes, which includes a plurality of lenses arranged along the optical axis between the front window protective glass and the chip. The lenses are arranged along the optical axis in the order of a first negative lens, a first positive lens, a first triplet lens, a second positive lens, and a second triplet lens from the front window protective glass to the chip. The first triplet lens is a zoom group, and the first triplet lens moves back and forth to achieve a zoom effect. The present invention provides a medical endoscope optical zoom adapter with a zoom effect of a focal length from 16mm to 32mm, an entrance pupil diameter of 4mm, a 4K resolution 1 / 2.5-inch chip, and a distortion of less than 0.3%. This adapter is an imaging objective lens with a simple structure, cost control and optimization. The present invention is based on the principle of optical imaging, and uses optical design software to repeatedly perform structural optimization design on the imaging objective lens to achieve aberration optimization.

Description

Technical Field

[0001] The invention belongs to a zoom objective optical system, and in particular relates to an adapter applied to a medical endoscope. The adapter is suitable for both a visible light source and an infrared light source. Background Art

[0002] Endoscope adapters are the connection system between endoscopes and imaging chips, and are mainly used in minimally invasive surgery in modern medicine. Ultra-high-definition endoscope adapters can present better medical images and provide higher medical diagnosis and treatment services. It is difficult to achieve an adapter with ultra-high-definition image quality and zoom at the same time.

[0003] At present, aspherical lenses are commonly used in objective optical systems with higher pixels, and the requirements of clarity and TV distortion are relatively easy to meet. The present invention uses glass aspherical lenses to design adapters, achieving the higher clarity and TV distortion requirements of aspherical surfaces. Summary of the invention

[0004] The purpose of the present invention is to use glass aspherical lenses to design optical zoom objective lenses, so as to achieve the higher definition and TV distortion requirements of aspherical lenses, and to use reasonable lens structures to achieve higher definition and zoom effects.

[0005] The structure adopted by the present invention is: a medical endoscope optical zoom 4K adapter, including a lens body, wherein the lenses are arranged along the optical axis in the order of a first negative lens, a first positive lens, a first triplet lens, a second positive lens, and a second triplet lens from the front window protective glass to the chip, wherein the first triplet lens is a zoom group.

[0006] Preferably, the lens includes an aperture surface disposed between a first triplet lens and a second positive lens.

[0007] Furthermore, the chip display surface is perpendicular to the optical axis, and the chip center is on the optical axis.

[0008] Furthermore, the focal length of the first positive lens is between 20 mm and 40 mm; the focal length of the first triplet lens is between 10 mm and 30 mm; the focal length of the second positive lens is between 30 mm and 60 mm; and the focal length of the second triplet lens is between -50 mm and -25 mm.

[0009] Furthermore, the refractive index of the first negative lens is between 1.50 and 1.70; the refractive index of the first positive lens is between 1.80 and 1.95; in the first triplet lens, the refractive index of the lens close to the first positive lens is between 1.80 and 1.95, the refractive index of the middle positive lens is between 1.45 and 1.60, and the refractive index of the negative lens close to the second positive lens is between 1.75 and 1.85; the refractive index of the second positive lens is between 1.45 and 1.60; in the second triplet lens, the refractive index of the positive lens close to the second positive lens is between 1.50 and 1.65, the refractive index of the middle lens is between 1.85 and 2.00, and the refractive index of the negative lens close to the chip is between 1.65 and 1.75.

[0010] Furthermore, the first negative lens is a lens with at least one aspherical surface.

[0011] The present invention is realized by a reverse telephoto objective lens with an aperture as the boundary, a negative lens group in front and a positive lens group in the back, wherein the front lens group includes a fixed negative focal length lens group and a variable focal length lens group. According to this structure, an optical objective lens with a similar structure is selected as the initial structure, and the chip size is changed. By changing the glass material, the focal length scaling and the optimized design of the aberration control, an endoscope adapter with excellent image quality is finally achieved.

[0012] The beneficial effects of the present invention are as follows: the present invention provides a medical endoscope optical zoom adapter with a focal length ranging from 16mm to 32mm, an entrance pupil diameter of 4mm, a 4K resolution 1 / 2.5-inch chip, and a distortion of less than 0.3%. The adapter is a simple structure, cost-controlled and optimized imaging objective. The present invention is based on the principle of optical imaging, and uses optical design software to repeatedly perform structural optimization design on the imaging objective to achieve aberration optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] Figure 2 It is the MTF curve diagram of the present invention. DETAILED DESCRIPTION

[0015] The specific implementation modes of the present invention are further described in conjunction with the accompanying drawings.

[0016] from Figure 1The structure adopted in the present invention is: a medical endoscope optical zoom 4K adapter, including a lens body, wherein the lenses are arranged along the optical axis in the order of the first negative lens 1, the first positive lens 2, the first triplet lens 3, the second positive lens 4, and the second triplet lens 5 from the front window protective glass 7 to the chip 6, wherein the first triplet lens is a zoom group. The lens also includes an aperture surface 8 placed between the first triplet lens and the second positive lens, and the lens includes an aperture surface placed between the first triplet lens and the second positive lens; the chip display surface is perpendicular to the optical axis, and the chip center is on the optical axis. The focal length of the first positive lens is between 20mm and 40mm; the focal length of the first triplet lens is between 10mm and 30mm; the focal length of the second positive lens is between 30mm and 60mm; the focal length of the second triplet lens is between -50mm and -25mm. The refractive index of the first negative lens is between 1.50 and 1.70; the refractive index of the first positive lens is between 1.80 and 1.95; in the first triplet, the refractive index of the lens close to the first positive lens is between 1.80 and 1.95, the refractive index of the middle positive lens is between 1.45 and 1.60, and the refractive index of the negative lens close to the second positive lens is between 1.75 and 1.85; the refractive index of the second positive lens is between 1.45 and 1.60; in the second triplet, the refractive index of the positive lens close to the second positive lens is between 1.50 and 1.65, the refractive index of the middle lens is between 1.85 and 2.00, and the refractive index of the negative lens close to the chip is between 1.65 and 1.75. The first negative lens is a lens with at least one aspherical surface.

[0017] The curvature radius, material, thickness of each lens and the distance between lenses are modified to optimize the aberration.

[0018] The following is an example of the coaxial placement of a 1 / 2.5-inch CMOS chip and an adapter to provide parameters of an embodiment of a medical endoscope optical zoom 4K adapter of the present invention:

[0019]

[0020]

[0021] Aspheric coefficients:

[0022] Surface Conic x4 x6 3 0 -3.51968E-05 5.88438E-08

[0023] Zoom data:

[0024] focal length 16mm 32mm Field of view 25 degrees 12.5 degrees F-number 4 8 D6 12.44 0.89 D10 0.20 11.75 D17 11.92 15.08

[0025] The final result is a medical endoscope optical zoom adapter with a focal length ranging from 16mm to 32mm, an entrance pupil diameter of 4mm, a 4K resolution 1 / 2.5-inch chip, and a distortion of less than 0.3%.

[0026] like Figure 2 This is the MTF curve of the present invention. In the figure, the MTF curves of each field of view at 309lp / mm are compactly bundled into a bundle greater than 0.11, indicating that the image of the lens is clear and uniform. The pixel of the 1 / 2.5-inch chip of 3840×2160 is 1.62 microns, and the corresponding Quinis line pair is 309lp / mm. Under this line pair, the MTF value>0.11 meets the resolution requirement of the chip.

Claims

1. A medical endoscope optical zoom 4K adapter, comprising a lens body, characterized in that: The lens body comprises, in order along the optical axis direction: a front window protection glass (7), a first negative lens (1), a first positive lens (2), a first triplet lens (3), a second positive lens (4), a second triplet lens (5), and a chip (6), wherein the first triplet lens is a zoom group, the components with optical refractive power in the lens body are only the above-mentioned nine lenses, the focal length of the first triplet lens is between 10 mm and 30 mm, the focal length of the second triplet lens is between -50 mm and -25 mm, and the first negative lens is a lens with at least one aspherical surface.

2. The medical endoscope optical zoom 4K adapter according to claim 1, characterized in that: The lens body also includes an aperture surface (8) disposed between the second positive lens (4) and the second triplet lens (5).

3. The medical endoscope optical zoom 4K adapter according to claim 1, characterized in that: The chip display surface is perpendicular to the optical axis, and the chip center is on the optical axis.

4. The medical endoscope optical zoom 4K adapter according to claim 1, characterized in that: The focal length of the first positive lens is between 20 mm and 40 mm; the focal length of the second positive lens is between 30 mm and 60 mm.

5. The medical endoscope optical zoom 4K adapter according to claim 1, characterized in that: The refractive index of the first negative lens is between 1.50 and 1.70; the refractive index of the first positive lens is between 1.80 and 1.95; in the first triplet lens, the refractive index of the lens close to the first positive lens is between 1.80 and 1.95, the refractive index of the middle positive lens is between 1.45 and 1.60, and the refractive index of the negative lens close to the second positive lens is between 1.75 and 1.85; the refractive index of the second positive lens is between 1.45 and 1.60; in the second triplet lens, the refractive index of the positive lens close to the second positive lens is between 1.50 and 1.65, the refractive index of the middle lens is between 1.85 and 2.00, and the refractive index of the negative lens close to the chip is between 1.65 and 1.75.

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