WO2023065827A1

WO2023065827A1 - Filter for use in fluorescence endoscope

Info

Publication number: WO2023065827A1
Application number: PCT/CN2022/115696
Authority: WO
Inventors: 王忠连; 阴晓俊; 赵帅锋; 任少鹏; 高鹏; 班超; 杨文华; 黄宏宇
Original assignee: 沈阳仪表科学研究院有限公司
Priority date: 2021-10-21
Filing date: 2022-08-30
Publication date: 2023-04-27
Also published as: CN113946007B; CN113946007A

Abstract

A filter (5) for use in a fluorescence endoscope, consisting of a K9 glass substrate and a wide-transmission-band deep-background negative filter film system. Under an incident condition, the wide-transmission-band deep-background negative filter film system has the following features: a wavelength range between a double-transmission area and a cut-off area is less than 3 nm; a range of a double-broadband transmission area reaches 350 nm or more; the basic structure of the wide-transmission-band deep-background negative filter film system is S|(αHβLγHβLαH)^ⁿ|A, wherein S represents the glass substrate; A represents air; H represents a high-refractive-index material; L represents a low-refractive-index material; the optical thickness of H and L is λ₀/4; α, β, and γ respectively represent matching coefficients of different materials; and n represents the number of cycles.

Description

Fluorescence Endoscopy Filters

technical field

The invention belongs to the field of optical films, in particular to a filter for fluorescence endoscope.

Background technique

Endoscope is a necessary equipment for minimally invasive surgery. In addition to the original functions of endoscope, fluorescence endoscope can also display fluorescently marked lesions in real time to reduce the difficulty of surgery. It is widely used in surgery (gastrointestinal, hepatobiliary, thyroid, Breast, etc.), gynecology, urology, thoracic surgery, etc. inspection, diagnosis and treatment. The fluorescent reagent used in the fluorescence endoscope is indocyanine green (ICG). The excitation spectrum of ICG is mainly in the range of 770nm-810nm, and the emission spectrum is mainly in the range of 810nm-850nm. Combining the fluorescence characteristics of ICG and visible spectrum imaging to design filters: 1. Satisfy high-definition imaging of visible light, with high transmission in the spectrum of 400nm-700nm; 2. Satisfy fluorescence imaging, high transmission in the spectrum of 825nm-850nm; 3. Avoid excitation light The interference of visible light imaging and fluorescence imaging, the spectrum is cut off at 710nm-810nm.

Conventional fluorescence filters play the role of separating excitation light and fluorescence. Among them, the higher the steepness between the excitation light and the emission light, the higher the energy utilization rate, the stronger the detected fluorescence signal, and the better the fluorescence imaging quality.

Filters are an important optical component in the optical path system of fluorescence endoscopes. The development of fluorescence endoscopes in my country only started in 2019. Due to the difficulty in designing and preparing filters for fluorescence endoscopes, it is almost impossible to produce them in China. In order to reduce the difficulty, the optical imaging system in Fig. 1 is often used. This structure reflects 50% of the spectral energy through a spectroscopic filter (spectral index: R (400nm-850nm) = 50%, T (400nm-850nm) = 50%) To the CMOS receiver with fluorescence filter (spectral index: T (825nm-850nm) ≥ 80%, OD (710nm-800nm) ≥ 2) to collect fluorescence images, and transmit 50% of the spectral energy to the filter with visible light (spectrum Index: T(400nm-700nm)≥80%, OD(710nm-800nm)≥2) CMOS receiver to collect visible light images. Disadvantages of this structure: 1. Due to the use of two CMOS receivers with optical filters, and then through the processing of composite images, the structure is complex and inconvenient to users; 2. The transmittance of the optical filters used is low and the cut-off depth is shallow. It greatly affects the imaging quality of the spectrum.

Contents of the invention

The invention aims at overcoming the disadvantages of the prior art, and provides a fluorescent endoscope optical filter which simplifies the structure of the fluorescent imaging system, has high steepness and wide transmission band characteristics when incident, and can improve the imaging quality.

In order to solve the problems of the technologies described above, the present invention is achieved in that:

A fluorescent endoscope filter, which is composed of a substrate and a wide transmission band deep background negative filter film system; the structure of the wide transmission band deep background negative filter film system is: S|(αHβLγHβLαH)^ ⁿ |A; where: S is glass substrate; A is air; H is high refractive index material; L is low refractive index material; H, L optical thickness is λ ₀ /4; Matching coefficient; n is the number of cycles.

Further, the wide transmission band deep background negative filter film of the present invention has the following characteristics under incident conditions: the wavelength range between the double transmission region and the cutoff region is less than 3nm; the range of the double broadband transmission region reaches more than 350nm.

Further, the H and L of the present invention use TiO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , HfO ₂ or SiO ₂ film materials.

The invention can simplify the structure of the fluorescent imaging system, has the characteristics of high steepness and wide transmission band, and can significantly improve the imaging quality. The novel high-steep, deep-background endoscope negative filter of the present invention can realize high-definition visible light imaging and fluorescence imaging of the endoscope at the same time with one filter, which simplifies the endoscope imaging system (see Figure 2). The cost is saved; and the imaging quality is improved due to the reduction of light splitting devices.

Compared with prior art, the present invention has following characteristics:

1. High steepness, satisfying that the wavelength range between the transmission region (T>90%) and the cutoff region (T<2%) is less than 3nm.

2. Wide transmission band, meeting the range of transmission area (T(400nm-700nm) and (821nm-900nm)>90%).

3. Deep background range (OD(720nm-800nm)>6).

4. The realization of the whole film system only needs two kinds of materials, and the process is relatively easy to realize.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the expression of the following content.

Fig. 1 is the existing fluorescence endoscope optical imaging system;

Fig. 2 is the fluorescence endoscope optical imaging system of installing this invention design filter additionally;

Fig. 3 is the schematic diagram of film layer structure of the present invention;

Fig. 4 is the transmission spectrum design curve of the present invention;

Fig. 5 is the background spectrum design curve of the present invention.

In the figure: 1, visible light filter; 2, lens group; 3, spectroscopic filter; 4, fluorescent filter; 5, fluorescent endoscope filter.

Detailed ways

As shown in the figure, the fluorescent endoscope filter is composed of a substrate and a wide transmission band deep background negative filter film system; among them, the wide transmission band deep background negative filter film system has the following characteristics under incident conditions : The wavelength range between the double transmission area and the cut-off area is less than 3nm; the range of the double broadband transmission area reaches more than 350nm (it has met the requirements for the use of endoscope filters, and the actual transmission area can be designed wider).

The basic structure of the high-steep depolarization film system of the present invention is:

S|(αHβLγHβLαH)^ ⁿ |A; where: S is glass substrate; A is air; H is high refractive index material; L is low refractive index material; H, L optical thickness is λ ₀ /4; α, β, γ, respectively represent the matching coefficient of different materials; n is the number of cycles.

The wide transmission band deep background negative filter film of the present invention has the following characteristics under incident conditions: the wavelength range between the double transmission region and the cutoff region is less than 3nm; the range of the double broadband transmission region reaches more than 350nm.

The H and L in the present invention use TiO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , HfO ₂ or SiO ₂ film materials.

The present invention proposes a five-layer cycle matching film system using high and low materials, and its structure is as follows:

S|(αHβLγHβLαH)^ ⁿ |A; where: S is an optical glass substrate (fused silica or K9); A is air; H is a material with a high refractive index; L is a material with a low refractive index; the optical thickness of H and L is λ ₀ /4; α, β, γ, respectively represent the matching coefficients of different materials, which determine the cut-off bandwidth and the width of the transmission area; n is the number of cycles.

The fluorescent endoscope filter designed by this method can realize the functions of adjustable cut-off background depth and cut-off bandwidth, and broadened transmission area. The filter can improve the imaging quality of the fluorescence endoscope, simplify the structure of the fluorescence endoscope, provide convenience for doctors during use, and provide assistance for minimally invasive precision medicine. In addition, the filter adopts H, L, and two kinds of materials to achieve physical thickness matching. The realization of the entire film system only needs two kinds of materials, which simplifies the process of process realization (generally, the design of negative filters adopts multiple gradient changes. Refractive index material design, process implementation is difficult, and cut-off depth is shallow).

Example:

According to the basic structure, the film system can be realized by selecting high and low materials according to actual needs, and an appropriate number of cycles (n). For example: H material: Nb ₂ O ₅ ; L material: SiO ₂ ; n=50.

Use computer software to optimize the set target value. In order to facilitate the process realization, the thin layer is removed to obtain the final film system. The physical thickness distribution of each layer in the design is shown in Table 1. Table 1 adopts H: Nb ₂ O ₅ , L: Nb ₂ O ₅ two kinds of materials to design and optimize the physical thickness distribution:

Table I

It can be understood that the above specific descriptions of the present invention are only used to illustrate the present invention and are not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or Equivalent replacements to achieve the same technical effect; as long as they meet the needs of use, they are all within the protection scope of the present invention.

Claims

A kind of fluorescence endoscope optical filter, it is characterized in that, is made of substrate and wide transmission band deep background negative filter film system; The structure of described wide transmission band deep background negative filter film system is: S|( αHβLγHβLαH)^ n |A; where: S is glass substrate; A is air; H is high refractive index material; L is low refractive index material; H, L optical thickness is λ 0 /4; α, β, γ, respectively Indicates the matching coefficient of different materials; n is the number of cycles.
The filter for fluorescence endoscope according to claim 1, characterized in that: the wide transmission band deep background negative filter film has the following characteristics under incident conditions: The wavelength range is less than 3nm; the double-broadband transmission range reaches above 350nm.
The fluorescent endoscope filter according to claim 2, characterized in that: said H and L are TiO 2 , Ta 2 O 5 , Nb 2 O 5 , HfO 2 or SiO 2 film materials.