A new polarization microscopy system with polarization splitting collimating prism and common detector

Abstract

A novel polarization splitting collimating prism and common detector polarization microscopy imaging system belongs to the technical field of optical systems. In order to solve the technical problems existing in the prior art, the system comprises an objective lens group, a novel polarization splitting collimating prism, a converging lens group and a detector; the objective lens group comprises a coaxially arranged imaging objective lens, an aperture stop and an infinity objective lens; the novel polarization splitting collimating prism comprises a front prism group, a middle prism group and a rear prism group; a light beam emitted from an object surface passes through the imaging objective lens in the objective lens group, converges to the aperture stop, passes through the infinity objective lens to form a parallel light beam, then passes through the front prism group of the novel polarization splitting collimating prism, undergoes a first birefringence to form two polarized light beams, passes through the middle prism group, undergoes a second birefringence to form four polarized light beams, passes through the rear prism group, and exits to form four polarized light beams with divided apertures, respectively entering the converging lens group in parallel to be converged, and finally forming an image on the detector target surface.

Description

Technical Field

[0001] The present invention specifically relates to a novel polarization beam splitting collimating prism common detector polarization microscopy imaging system, belonging to the technical field of optical systems. Background Art

[0002] Polarization imaging technology organically combines optical intensity imaging and polarization technology to simultaneously obtain the two-dimensional spatial position information of the target object and measure the target's polarization state. It can effectively detect and identify targets in complex environments that are difficult to identify by conventional means, such as man-made objects or underwater targets, especially hidden or camouflaged targets that cannot be effectively imaged by traditional cameras or video cameras. Therefore, polarization imaging technology has enormous development potential and is a hot topic for research and application development both domestically and internationally. Optical polarization microscopy can effectively utilize the interaction between polarized light and matter to obtain richer sample information. Combining polarization with microscopy can provide more characteristic information about the measured object.

[0003] Early polarization imaging systems generally only captured the linear polarization component of a target. However, with the advancement of target detection technology, incomplete polarization imaging systems are increasingly unable to meet the needs of modern target detection and identification. Existing amplitude- and aperture-based polarization imaging systems require two or more polarizing prisms, each receiving light from two or more independent detectors. Unavoidable differences between the detectors affect the quality of the resulting polarization image. The polarization detector used in focal-plane polarization imaging systems is obtained by directly coupling a polarizer array to the detector's focal plane. Micro-polarization elements are difficult to manufacture due to their small size, especially in the visible light band, and are currently not readily available in China.

[0004] In the Acta Optica Sinica, Liu Jing et al. published an article titled "Design of a Simultaneous Polarization Imaging System Using Dual Split Wollaston Prisms." This solution combines amplitude and aperture division to simultaneously acquire four polarization component images on two detectors, providing a solution for polarization imaging. However, parameter differences between the optical systems and imaging detectors of each channel in this technical solution can affect polarization measurement. Furthermore, the energy efficiency of the beam splitting prism is low, requiring further improvement. Summary of the Invention

[0005] In order to solve the technical problems in the prior art that the differences in the optical systems and imaging detector parameters of each channel affect the polarization measurement, and the use of a beam splitter prism leads to low energy utilization, the present invention proposes a new polarization splitting collimating prism common detector polarization microscopy imaging system.

[0006] The technical solution of the present invention to solve the technical problem is:

[0007] A novel polarization beam splitting collimating prism and common detector polarization microscopy imaging system comprises an objective lens group, a novel polarization beam splitting collimating prism, a converging lens group, and a detector; the objective lens group comprises a coaxially arranged imaging objective lens, an aperture stop, and an infinity objective lens; the imaging objective lens performs a primary imaging; the aperture stop eliminates stray light and limits the imaging range on a plane; the infinity objective lens provides a parallel light beam for subsequent systems;

[0008] The novel polarization beam splitting collimating prism comprises a front group prism, a middle group prism, and a rear group prism. The three groups of prisms are glued together in sequence, and the directions of the optical axes of the prisms are at a certain angle to each other. The first birefringence of the front group prism occurs at the interface between the front group prism and the middle group prism, and the direction of its optical axis is parallel to the paper surface, with a structural angle of β. The light beam is incident on the front group prism in parallel, and the incident angle is β. The second birefringence of the middle group prism occurs at the interface between the middle group prism and the rear group prism, and the direction of its optical axis is perpendicular to the angle of the optical axis of the front group prism and parallel to the paper surface. The rear group prism has an upper structural angle of θ1 and a lower structural angle of θ2, which ensure that the polarized light beam is emitted in parallel and adjust the beam splitting distance of the polarized light beam, and the direction of its optical axis is perpendicular to the paper surface.

[0009] The converging lens group includes converging lens 1, converging lens 2, converging lens 3 and converging lens 4;

[0010] The light beam emitted from the object surface passes through the imaging objective lens in the objective lens group, converges to the aperture diaphragm, and then passes through the infinity objective lens to form a parallel light beam. Then, it passes through the front group of prisms of the new polarization splitting collimating prism, where it undergoes the first birefringence to form two polarized light beams. It passes through the middle group of prisms where it undergoes the second birefringence to form four polarized light beams. It is emitted through the rear group of prisms to form four polarized light beams with divided apertures and enter the four converging lenses in the converging lens group in parallel to converge, and finally form an image on the detector target surface.

[0011] Beneficial effects of the present invention:

[0012] The present invention utilizes a combination of three components of beam splitting prisms to achieve simultaneous imaging of multiple polarization states using a common detector. The front objective lens of the microscope provides a parallel light beam for subsequent polarization channels to achieve single-channel polarization microscopic imaging, and the polarization image is received by the same detector. By selecting an optical system with consistent parameters, additional polarization measurement errors introduced by parameter differences between the optical systems of each channel and the imaging detectors, as well as energy loss caused by the beam splitting prism, can be avoided.

[0013] Polarization microscopy systems enable multi-polarization state common-detector imaging with a simple and compact structure, while simultaneously improving target recognition probability, observation efficiency, and imaging quality in low-light conditions. They play a vital role in enhancing microscopic image resolution and contrast, studying biological tissues, and quantitatively analyzing the crystal structure and orientation of samples. They are widely applicable in fields such as biology, materials science, medical imaging, and optical information science. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a novel polarization beam splitting collimating prism and common detector polarization microscopy imaging system of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to the accompanying drawings.

[0016] like Figure 1 As shown, a novel polarization splitting collimating prism and common detector polarization microscopy imaging system includes an objective lens group 1, a novel polarization splitting collimating prism 2, a converging lens group 3 and a detector 4.

[0017] The objective lens assembly 1 includes an imaging objective lens 1-1, an aperture stop 1-2, and an infinity objective lens 1-3 that are coaxially arranged in sequence.

[0018] The imaging objective lens 1-1 performs one imaging.

[0019] The aperture stop 1-2 eliminates stray light and limits the imaging range on the plane.

[0020] The infinity objective lens 1-3 provides a parallel light beam for the subsequent system.

[0021] The novel polarization beam splitting collimating prism 2 comprises three groups of beam splitting prisms whose optical axes are perpendicular to each other and glued together in sequence. The light beam undergoes two birefringences in the prisms. The refractive index of the front group prism 2-1 is n1, the refractive index of the middle group prism 2-2 is n2, and the refractive index of the rear group prism 2-3 is n3, where n1=n3.

[0022] The first birefringence of the front prism 2-1 occurs at the interface between the front prism 2-1 and the middle prism 2-2. The optical axis is parallel to the paper surface, the structural angle is β, and the light beam is incident on the front prism 2-1 in parallel with the incident angle β.

[0023] The second birefringence of the middle prism 2-2 occurs at the interface between the middle prism 2-2 and the rear prism 2-3, and its optical axis is perpendicular to the optical axis of the front prism 2-1 and parallel to the paper surface.

[0024] The rear group prism 2-3 has an upper structural angle of θ1 and a lower structural angle of θ2, which ensures that the polarized light beam is emitted in parallel and adjusts the splitting distance of the polarized light beam, and the optical axis direction is perpendicular to the paper surface.

[0025] The converging lens group 3 includes a converging lens 1 3-1, a converging lens 2 3-2, a converging lens 3-3 and a converging lens 4 3-4;

[0026] The light beam emitted from the object surface first passes through the imaging objective lens 1-1 in the objective lens group 1 and converges to the aperture diaphragm 1-2. Then it passes through the infinite objective lens 1-3 and is emitted in parallel. It reaches the front prism 2-1 of the new polarization splitting collimator prism 2 and undergoes the first birefringence to form two polarized light beams. The incident angle is β, and the light is split into o light and e light by the middle prism 2-2. The refraction angle of o light and e light is i o and i e , n 1o and n 1e are the refractive indices of light o and light e in the front prism 2-1. According to the law of refraction, we have:

[0027] n2sini o =n 1o sinβ (1)

[0028] n2sini e =n 1e sinβ (2)

[0029] According to formulas (1) and (2), the refraction angles of o-light and e-light are calculated to be i o and i e ;

[0030] Then, it passes through the middle prism 2-2 and undergoes a second double refraction to form four polarized light beams, among which the refractive indices of o light and e light in the rear prism 2-3 are n and n respectively. 3o and n 3e , o light forms two polarized light beams, oo light and oe light, the refraction angles are β and β respectively e , the e light forms two polarized light beams, ee light and eo light, and the refraction angles are β and β respectively o , according to the law of refraction:

[0031] o Light:

[0032] n2sini o =n 3o sinβ (3)

[0033] n2sini o =n 3e sinβ e (4)

[0034] E-light:

[0035] n2sini e =n 3e sinβ (5)

[0036] n2sini e =n 3o sinβ o (6)

[0037] According to formulas (3), (4), (5) and (6), the refraction angles of oo light, oe light, eo light and ee light are calculated;

[0038] The four polarized light beams oo, oe, eo and ee are emitted from the rear prism 2-3 of the polarization splitting collimating prism 2 in parallel. Since n1=n3, the oo and ee are emitted in parallel. If the eo and oe are emitted in parallel, the upper structural angle θ1 and the lower structural angle θ2 of the rear prism 2-3 are used to obtain the refraction angle of the eo light at the exit end of the rear prism 2-3 is θ1-90°, the refraction angle of the oe light is θ2-90°, and n a is the refractive index of air, according to the law of refraction:

[0039] oe light:

[0040] n 3e sin(θ2+β-90°-β e )=n a sin(θ2-90°) (7)

[0041] eo light:

[0042] n 3o sin(θ1-β-90°+β o )=n a sin(θ1-90°) (8)

[0043] The upper and lower structural angles of the rear prism group 2-3 can be calculated based on the structural angle β of the front prism group 2-1 and formulas (7) and (8). The four parallel polarized light beams are then converged by the converging lens 1 3-1, the converging lens 2 3-2, the converging lens 3 3-3 and the converging lens 4 3-4 in the converging lens group 3, and finally imaged on the detector 4.

[0044] Example:

[0045] like Figure 1 As shown, a novel polarization beam splitting collimating prism and common detector polarization microscopy imaging system includes an objective lens group 1, a novel polarization beam splitting collimating prism 2, a converging lens group 3 and a detector 4.

[0046] The objective lens assembly 1 includes an imaging objective lens 1-1, an aperture stop 1-2, and an infinity objective lens 1-3 that are coaxially arranged in sequence.

[0047] The imaging objective lens 1-1 performs one imaging.

[0048] The aperture stop 1-2 eliminates stray light and limits the imaging range on the plane.

[0049] The infinity objective lens 1-3 provides a parallel light beam for the subsequent system.

[0050] The novel polarization splitting collimating prism 2 comprises three groups of prisms with mutually perpendicular optical axes glued together in sequence. The light beam undergoes two birefringences in the prisms. The refractive index of the middle group prism 2-2 is n2=1.45. The refractive indexes of the o-light and e-light in the front group prism 2-1 and the rear group prism 2-3 are n2=1.45. 1o =n 3o =1.658,n 1e =n 3e =1.486.

[0051] The first birefringence of the front prism group 2-1 occurs at the interface between the front prism group 2-1 and the middle prism group 2-2, the optical axis direction is parallel to the paper surface, the structural angle is β = 25°, and the light beam is incident on the front prism group 2-1 in parallel, and the incident angle is β = 25°.

[0052] The second birefringence of the middle prism 2-2 occurs at the interface between the middle prism 2-2 and the rear prism 2-3, and its optical axis is perpendicular to the optical axis of the front prism 2-1 and parallel to the paper surface.

[0053] The rear group prism 2-3 has an upper structural angle of θ1 and a lower structural angle of θ2, which ensures that the polarized light beam is emitted in parallel and adjusts the splitting distance of the polarized light beam, and the optical axis direction is perpendicular to the paper surface.

[0054] The light beam emitted from the object surface first passes through the imaging objective lens 1-1 in the objective lens group 1 and converges to the aperture diaphragm 1-2. Then it is emitted in parallel through the infinite objective lens 1-3 and reaches the front prism 2-1 of the new polarization beam splitting collimator prism 2. It undergoes the first birefringence to form two polarized light beams o and e. When the incident angle β = 25°, the refraction angles of o and e are calculated according to the refraction law. o =28.9°, i e =25.7°.

[0055] Then, it passes through the middle prism 2-2 and undergoes a second double refraction to form four polarized light beams: oo light, oe light, eo light, and ee light. Among them, the o light forms two polarized light beams, and the refraction angles of the oo light and the oe light are β and β respectively. o , the e light forms two polarized light beams, ee light and eo light, and the refraction angles are β and β respectively e , calculated according to the law of refraction, β o =22.2°, β e =28.1°.

[0056] The four polarized light beams emitted from the rear prism 2-3 of the polarization splitting collimating prism 2 are emitted in parallel. Since n1=n3, the oo light and the ee light are emitted in parallel. If the oe light and the eo light are emitted in parallel, using the upper structural angle θ1 and the lower structural angle θ2 of the rear prism 2-3, it is obtained that the refraction angle of the eo light at the exit end of the rear prism 2-3 is θ1-90°, the refraction angle of the oe light is θ2-90°, and the refractive index of air is n a =1, according to the law of refraction, the upper structural angle θ1 of the rear prism 2-3 is 97.06°, and the lower structural angle θ2 is 99.48°.

[0057] The four beams of parallel polarized light are then converged by converging lens 1 3 - 1 , converging lens 2 3 - 2 , converging lens 3 3 - 3 and converging lens 4 3 - 4 in the converging lens group 3 , and are finally imaged on the detector 4 .

Claims

1. A new polarization beam splitting collimating prism common detector polarization microscopy imaging system, characterized by: It comprises an objective lens group (1), a novel polarization beam splitting collimating prism (2), a converging lens group (3) and a detector (4); The objective lens group (1) comprises an imaging objective lens (1-1), an aperture stop (1-2) and an infinity objective lens (1-3) which are coaxially arranged in sequence; The imaging objective lens (1-1) performs a single imaging operation; The aperture stop (1-2) eliminates stray light and limits the imaging range on the plane; The infinite objective lens (1-3) provides a parallel light beam for the subsequent system; The novel polarization splitting collimating prism (2) comprises a front group prism (2-1), a middle group prism (2-2) and a rear group prism (2-3), wherein three groups of splitting prisms with mutually perpendicular optical axes are glued together in sequence, and the light beam undergoes two double refractions in the prisms; The first birefringence of the front prism group (2-1) occurs at the interface between the front prism group (2-1) and the middle prism group (2-2), the optical axis of which is parallel to the paper surface, the structural angle is β, and the light beam is incident on the front prism group 2-1 in parallel, with an incident angle of β; The second birefringence of the middle prism (2-2) occurs at the interface between the middle prism (2-2) and the rear prism (2-3), and the optical axis direction is perpendicular to the optical axis of the front prism (2-1) and parallel to the paper surface; The rear prism (2-3) has an upper structural angle of θ1 and a lower structural angle of θ2, which ensures that the polarized light beam is emitted in parallel and adjusts the splitting distance of the polarized light beam, and the optical axis direction is perpendicular to the paper surface; The converging lens group (3) comprises converging lens 1 (3-1), converging lens 2 (3-2), converging lens 3 (3-3) and converging lens 4 (3-4); The light beam emitted from the object surface passes through the imaging objective lens (1-1) in the objective lens group (1), converges to the aperture stop (1-2), passes through the infinite objective lens (1-3) to form a parallel light beam, then passes through the front prism (2-1) of the novel polarization splitting collimating prism (2) to generate a first birefringence to form two polarized light beams, passes through the middle prism (2-2) to generate a second birefringence to form four polarized light beams, passes through the rear prism (2-3) to be emitted, and forms four polarized light beams with divided apertures, which enter the convergent lens group (3) in parallel and are finally imaged on the target surface of the detector (4).

2. The novel polarization splitting collimating prism common detector polarization microscopy imaging system according to claim 1, characterized in that: The refractive index of the front group prism (2-1) is n1, the refractive index of the middle group prism (2-2) is n2, and the refractive index of the rear group prism (2-3) is n3, wherein n1=n3.

3. The novel polarization splitting collimating prism common detector polarization microscopy imaging system according to claim 1, characterized in that: The specific optical path relationship is as follows: the light beam emitted from the object surface first passes through the imaging objective lens (1-1) in the objective lens group (1) and converges to the aperture diaphragm (1-2), then passes through the infinite objective lens (1-3) and is emitted in parallel, and reaches the front group prism (2-1) of the new polarization splitting collimating prism (2) to undergo the first double refraction to form two polarized light beams, wherein the incident angle is β, and is incident on the middle group prism (2-2) to split into o light and e light, and the refraction angle of o light and e light is i o and i e , n 1o and n 1e are the refractive indices of light o and light e in the front prism (2-1), and the refraction angles of light o and light e are calculated to be i according to the law of refraction. o and i e ; After passing through the middle prism (2-2), a second double refraction occurs to form four polarized light beams, among which the refractive indexes of o light and e light in the rear prism (2-3) are n and n respectively. 3o and n 3e , o light forms two polarized light beams, oo light and oe light, the refraction angles are β and β respectively e , the e light forms two polarized light beams, ee light and eo light, and the refraction angles are β and β respectively o , according to the law of refraction, the refraction angles of oo light, oe light, eo light and ee light are calculated; The four polarized light beams oo, oe, eo and ee are emitted from the rear prism (2-3) of the novel polarization splitting collimating prism (2) in parallel. Since n1=n3, the oo and ee are emitted in parallel. If the eo and oe are emitted in parallel, the upper structural angle θ1 and the lower structural angle θ2 of the rear prism (2-3) are used to obtain the refraction angle of the eo light at the exit end of the rear prism (2-3) as θ1-90° and the refraction angle of the oe light as θ2-90°. a is the refractive index of air, and the upper structural angle θ1 and the lower structural angle θ2 of the rear prism (2-3) are calculated according to the law of refraction and the structural angle β of the front prism (2-1). The four parallel polarized lights are then respectively converged by converging lens 1 (3-1), converging lens 2 (3-2), converging lens 3 (3-3) and converging lens 4 (3-4) in the converging lens group (3), and finally imaged on the detector (4).

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