Medium-wave infrared simulation optical system optimization method

Abstract

The invention relates to the technical field of optical detection, provides a medium-wave infrared simulation optical system optimization method, and aims to solve the problems that an existing system is poor in light path turning and stray light management and control, the illumination angle is difficult to restrain, and the whole system is too long. The system comprises a medium-wave infrared optical engine and an optical system, the optical engine is composed of a blackbody radiation source, an illumination system, a display device and a TIR prism group, and the optimization core is the TIR prism group. During optimization, an adaptive TIR prism group structure is selected firstly, it is determined that the TIR prism group structure is composed of three prisms, and a specific material is selected; three prisms are respectively designed, so that the prisms sequentially realize light beam bending and uniform distribution, light splitting modulation is carried out according to the tilt angle of the micro-mirror, the accurate direction of an on-state emergent light beam is ensured, and off-state and flat-state stray light of a display device is guided out. According to the method, the illumination angle can be stably controlled, the rear intercept of the light path is reduced, the light beam modulation precision and the system compactness are improved, and the comprehensive performance and the practical value of the medium-wave infrared simulation optical system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, and specifically to an optimization method for a mid-wave infrared analog optical system. Background Technology

[0002] In the field of mid-wave infrared analog optical systems, existing systems have significant shortcomings in optical path design and core component compatibility. Traditional solutions suffer from poor optical path deflection and stray light control, making it difficult to effectively separate stray light from different operating states of display devices and easily interfering with beam modulation accuracy.

[0003] Meanwhile, the constraints on the illumination angle are significant, making it difficult to stably match the target surface requirements of display devices. Furthermore, the unreasonable backstop design of the optical path results in an excessively long overall system length, hindering miniaturized integration. These issues collectively limit the performance improvement and application scenarios of mid-wave infrared analog optical systems, making it difficult to meet the comprehensive requirements of system compactness, stability, and imaging quality in practical applications. Summary of the Invention

[0004] The purpose of this invention is to provide an optimization method for a mid-wave infrared analog optical system.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for optimizing a mid-wave infrared analog optical system, the method comprising the following steps:

[0007] Step 1: Obtain the specific structure of the system. The mid-wave infrared simulated optical system mainly consists of a mid-wave infrared optical engine and a mid-wave infrared optical system. The mid-wave infrared optical engine consists of a blackbody radiation source, a mid-wave infrared illumination system, a mid-wave infrared display device, and a mid-wave infrared TIR prism group. In the mid-wave infrared simulated optical system, the infrared radiation emitted by the blackbody radiation source is focused and expanded by the illumination system, so that the diameter of the outgoing light spot is large enough to cover the incident surface of the TIR prism group. Then, the beam enters the TIR prism group, undergoes total internal reflection, and illuminates the target surface of the mid-wave infrared display device. The TIR prism group is optimized.

[0008] Step 2: The optimization process is as follows:

[0009] (1) Selection of TIR prism group structure: Select DLP7000 type DMD as display device, in the mid-wave infrared band, make the angle between the incident light of the illumination beam and the normal of the DMD target surface 10.5°; the optical path is the TIR prism group deflection optical path; the TIR prism group includes three prisms; when the illumination system enters the TIR prism group, the incident angle is... greater than the critical angle At that time, according to Snell's law, total internal reflection occurs at the prism surface. The reflected light is modulated by the DMD, and the angle of reflection of the reflected light... Less than the critical angle At that time, light is transmitted through the TIR prism group and enters the optical system;

[0010] (2) Determine the parameters of the three prisms in the TIR prism assembly and the materials used to prepare them;

[0011] (3) The three prisms are optimized, wherein the first prism is The second prism is The third prism is .

[0012] Specifically, the size parameters of the three prisms in the TIR prism assembly are calculated primarily based on the total internal reflection condition, as shown in the following formula: In the formula, The refractive index of air; Given the refractive index of the prism material, ZnS was chosen as the prism material. The refractive index of ZnS changes within the working wavelength range of 3μm to 5μm. =2.251±0.05.

[0013] Specifically, the design of the first prism: the first prism The illumination beam is deflected and evenly distributed onto the DMD image plane, according to the formula The incident angle of the ray incident on the upper edge of the beam incident on the hypotenuse AB is... The angle at which the lower edge of the reflected beam from the DMD is incident on the hypotenuse AB. The Angle of the hypotenuse of the prism The conditions to be met are: It can be concluded that prism hypotenuse angle Should meet In the formula, For mid-wave infrared optical systems ; This is the deflection angle of the DMD; The light cone angle of the illumination beam is given; the diagonal length of the DMD is also known. Based on geometric relationships, the first prism can be calculated. thickness for ;

[0014] Design of the second prism: The second prism The beam is split and modulated based on the tilt angle of the micromirrors under different DMD states, wherein the incident light... The first hypotenuse and hypotenuse Parallel, with a 1.5μm air gap between the prisms; according to the formula It can be concluded that The second hypotenuse angle Should meet The second prism thickness for In the formula, for The point of exit ray and the point of incident ray are at Distance between the front surfaces;

[0015] Design of the third prism: The third prism Ensure that the direction of the emitted beam from the DMD in the open state is parallel to the optical axis of the DMD and enters the optical system; its two hypotenuses are parallel to... and The hypotenuse of the third prism is perpendicular to the DMD image plane; according to geometric relationships, the third prism... thickness for In the formula, and These are the distances marked in the text.

[0016] The beneficial effects of this invention are as follows:

[0017] This method, by optimizing the TIR prism assembly, can effectively extract stray light from the off-state and flat-state of the display device, improving beam modulation accuracy. Simultaneously, it can stably control the illumination angle of the optical path, better matching the target surface requirements of the display device. It can also reduce the backstop and shorten the overall length of the optical path, contributing to system miniaturization and significantly enhancing the overall performance and practical value of the mid-wave infrared analog optical system.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is the optical path diagram of the mid-wave infrared analog optical system of the present invention;

[0020] Figure 2 This is a schematic diagram illustrating the working principle of the DMD micromirror of this invention.

[0021] Figure 3 The optical path diagram of the TIR prism assembly is shown.

[0022] Figure 4 This is a schematic diagram of beam composition using a TIR prism.

[0023] Figure 5 Design diagram for prism parameters. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] like Figures 1-5 As shown, an optimization method for a mid-wave infrared analog optical system includes the following steps:

[0026] Step 1: Obtain the specific structure of the system, such as Figure 1 The mid-wave infrared simulated optical system mainly consists of a mid-wave infrared optical engine and a mid-wave infrared optical system. The mid-wave infrared optical engine comprises a blackbody radiation source, a mid-wave infrared illumination system, a mid-wave infrared display device, and a mid-wave infrared TIR prism assembly. In the mid-wave infrared simulated optical system, the infrared radiation emitted by the blackbody radiation source is focused and expanded by the illumination system, ensuring the output beam diameter is large enough to cover the incident surface of the TIR prism assembly. The beam then undergoes total internal reflection within the TIR prism assembly and illuminates the target surface of the mid-wave infrared display device. The TIR prism assembly is designed with optimization in mind.

[0027] Step 2: The optimization process is as follows:

[0028] (1) Select a TIR prism assembly structure, such as Figure 2 A DLP7000 type DMD was selected as the display device. In the mid-infrared band, the angle between the incident light of the illumination beam and the normal of the DMD target surface was 10.5°. Figure 3 The optical path is a TIR prism group folding optical path, which easily controls the constrained illumination angle of the DMD. Through reasonable prism group design, all stray light from the DMD's off-state and flat-state can be guided out of the optical path. Furthermore, the TIR prism group can reduce the back intercept in the optical path, shortening the total length of the optical path and contributing to the overall miniaturization of the system. The working principle and design principle of the TIR prism group are as follows: Figure 4 and Figure 5 The incident angle of the light beam entering the TIR prism group from the illumination system greater than the critical angle At that time, according to Snell's law, total internal reflection occurs at the prism surface. The reflected light is modulated by the DMD, and the angle of reflection of the reflected light... Less than the critical angle At that time, light is transmitted through the TIR prism group and enters the optical system;

[0029] (2) Determine the parameters of the prism assembly and its fabrication materials: The TIR prism assembly consists of three prisms. The calculation of the size parameters of the three prisms is mainly based on the total internal reflection condition, and the formula is as follows: In the formula, The refractive index of air; Given the refractive index of the prism material, ZnS was chosen as the prism material. The refractive index of ZnS changes within the working wavelength range of 3μm to 5μm. =2.251±0.05;

[0030] (3) The three prisms are optimized, wherein the first prism is The second prism is The third prism is .

[0031] Specifically, the design of the first prism, the first prism The illumination beam is deflected and evenly distributed onto the DMD image plane, according to the formula The incident angle of the ray incident on the upper edge of the beam incident on the hypotenuse AB is... The angle at which the lower edge of the reflected beam from the DMD is incident on the hypotenuse AB. , Angle of the hypotenuse of the prism The conditions to be met are: It can be concluded that prism hypotenuse angle Should meet In the formula, For mid-wave infrared optical systems ; This is the deflection angle of the DMD; Let be the cone angle of the illumination beam. Given the diagonal length of the DMD. Based on geometric relationships, the first prism can be calculated. thickness for ;

[0032] The second prism design, the second prism The beam is split and modulated based on the tilt angle of the micromirrors under different DMD states, wherein the incident light... The first hypotenuse and hypotenuse The prisms are parallel, with a 1.5 μm air gap between them. According to the formula... It can be concluded that The second hypotenuse angle Should meet The second prism thickness for In the formula, for The point of exit ray and the point of incident ray are at Distance between the front surfaces;

[0033] The third prism design, the third prism Ensure that the direction of the emitted beam from the DMD in the open state is parallel to the optical axis of the DMD and enters the optical system. Its two hypotenuses are parallel to... and The hypotenuse of the third prism is perpendicular to the image plane of the DMD. Based on geometric relationships, the third prism... thickness for In the formula, and These are the distances marked in the text.

[0034] The design parameters for the TIR prism assembly are as follows:

[0035] Substituting the specific parameter values ​​into the solution formula for the three prisms, the main design parameters of the mid-wave infrared TIR prism group can be obtained, as shown in the table below:

[0036]

[0037] The table above shows the main design parameters of the three prisms in the mid-wave infrared (TIR) ​​prism group, the incident surface angles of the first and second prisms, and the equivalent thickness of the three prisms along the optical axis.

[0038] In summary: The optimization result is in Within the operating wavelength range of 3μm to 5μm, the refractive index of ZnS changes as follows: =2.251±0.05; hypotenuse angle β 1=19, prism equivalent thickness L 1 = 30; hypotenuse angle β 2=12, prism equivalent thickness L 2 = -4.4; prism equivalent thickness L 3 = 8.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for optimizing a mid-wave infrared analog optical system, characterized in that, The method includes the following steps: Step 1: Obtain the specific structure of the system. The mid-wave infrared simulated optical system mainly consists of a mid-wave infrared optical engine and a mid-wave infrared optical system. The mid-wave infrared optical engine consists of a blackbody radiation source, a mid-wave infrared illumination system, a mid-wave infrared display device, and a mid-wave infrared TIR prism group. In the mid-wave infrared simulated optical system, the infrared radiation emitted by the blackbody radiation source is focused and expanded by the illumination system, so that the diameter of the outgoing light spot is large enough to cover the incident surface of the TIR prism group. Then, the beam enters the TIR prism group, undergoes total internal reflection, and illuminates the target surface of the mid-wave infrared display device. The TIR prism group is optimized. Step 2: The optimization process is as follows: (1) Selection of TIR prism group structure: Select DLP7000 type DMD as display device, in the mid-wave infrared band, make the angle between the incident light of the illumination beam and the normal of the DMD target surface 10.5°; the optical path is the TIR prism group deflection optical path; the TIR prism group includes three prisms; when the illumination system enters the TIR prism group, the incident angle is... greater than the critical angle At that time, according to Snell's law, total internal reflection occurs at the prism surface. The reflected light is modulated by the DMD, and the angle of reflection of the reflected light... Less than the critical angle At that time, light rays are transmitted through the TIR prism group and enter the optical system; (2) Determine the parameters of the three prisms in the TIR prism assembly and the materials used to prepare them; (3) The three prisms are optimized, wherein the first prism is The second prism is The third prism is .

2. The method for optimizing a mid-wave infrared analog optical system as described in claim 1, characterized in that, In the TIR prism assembly, the size parameters of the three prisms are calculated primarily based on the total internal reflection condition, as shown in the following formula: In the formula, The refractive index of air; Given the refractive index of the prism material, ZnS was chosen as the prism material. The refractive index of ZnS changes within the working wavelength range of 3μm to 5μm. =2.251±0.

05.

3. The method for optimizing a mid-wave infrared analog optical system as described in claim 1, characterized in that, Design of the first prism: The first prism The illumination beam is deflected and evenly distributed onto the DMD image plane, according to the formula The incident angle of the ray incident on the upper edge of the beam incident on the hypotenuse AB is... The angle at which the lower edge of the reflected beam from the DMD is incident on the hypotenuse AB. The Angle of the hypotenuse of the prism The conditions to be met are: It can be concluded that prism hypotenuse angle Should meet In the formula, For mid-wave infrared optical systems ; This is the deflection angle of the DMD; The cone angle of the illumination beam; Given the length of the diagonal of the DMD Based on geometric relationships, the first prism can be calculated. thickness for ; Design of the second prism, the second prism The beam is split and modulated based on the tilt angle of the micromirrors under different DMD states, wherein the incident light... The first hypotenuse and hypotenuse Parallel, with a 1.5μm air gap between the prisms; according to the formula It can be concluded that The second hypotenuse angle Should meet The second prism thickness for In the formula, for The point of exit ray and the point of incident ray are at Distance between the front surfaces; The design of the third prism, the third prism Ensure that the direction of the emitted beam from the DMD in the open state is parallel to the optical axis of the DMD and enters the optical system; its two hypotenuses are parallel to... and The hypotenuse of the third prism is perpendicular to the DMD image plane; according to geometric relationships, the third prism... thickness for In the formula, and These are the distances marked in the text.

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