Compact Multi-Spectral Three-Viewfield Television Optical System

Abstract

The present invention discloses a compact multi-spectral three-field-of-view television optical system, which is composed of a large-field-of-view optical channel, a medium-field-of-view optical channel, and a small-field-of-view optical channel. There is a semi-transmissive and semi-reflective energy splitting cube prism between the medium-field-of-view optical channel and the large / small-field-of-view optical channels. It transmits the incident light from the medium-field-of-view optical channel to the CMOS target surface; and reflects the incident light from the large / small-field-of-view optical channels to the CMOS target surface. There is a total reflection plane mirror for insertion / extraction between the large-field-of-view optical channel and the small-field-of-view optical channels. When inserted, it is the large-field-of-view optical channel, which reflects the incident light from the large-field-of-view optical channel to the cube prism, and then reflects it to the CMOS target surface through the cube prism; when extracted, it is the small-field-of-view optical channel, and the incident light from the small-field-of-view optical channel is reflected twice by the reflection prism and the splitting cube prism to the CMOS target surface.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic systems, and relates to an optical system with a three-field-of-view optical channel, and particularly to a three-field-of-view compact optical system that takes into account the visible light and near-infrared multi-spectral ranges. This optical system can be used in optoelectronic systems such as vehicle-mounted, airborne, and shipborne television cameras. Background Art

[0002] A television camera is an important part of an optoelectronic system, which can provide images of external scenes for operators to detect, identify, and track targets during the day. Its optical system directly affects the combat effectiveness of the optoelectronic system, and it is required to have a very long operating distance and high-resolution imaging performance for different targets, and meet the requirements of high integration and small volume of the system. At present, television optical systems have been widely used in fields such as navigation, observation, and tracking. However, single-field-of-view television optical systems cannot meet the development needs of modern television optical systems due to their single function. Three-field-of-view television optical systems have three different fields of view, large, medium, and small, and are widely used in modern television optical systems. The large field of view can be used for large-range target search and identification of larger targets; the medium field of view can be used for further observation and identification of targets and tracking of medium-sized targets; the small field of view can be used for precise tracking and aiming of targets and detection of low, slow, and small targets.

[0003] The working bands of television optical systems are mainly distributed in the visible light (0.45 μm - 0.7 μm) and near-infrared (0.65 μm - 0.9 μm) bands. The imaging technologies of single-band television optical systems are very mature, but each has its own advantages and disadvantages. The near-infrared band has a high atmospheric transmittance and certain fog-penetrating ability, which is beneficial to increasing the detection distance. However, the response efficiency of imaging devices is low, and the imaging characteristics are different from those observed by the human eye, and it is only applicable to black-and-white imaging devices. The visible light band has a low atmospheric transmittance, but the response efficiency of imaging devices is high, and the imaging characteristics are similar to those of the human eye, and it is applicable to both black-and-white and color imaging devices. Therefore, by using spectra in different wavelength ranges, the detection and identification capabilities of television cameras for targets in different environments can be improved.

[0004] At present, the implementation methods of the three-field television optical system are mainly the punch-in and punch-out method, the axial movement method and the multi-field coupling method. The punch-in and punch-out method is to change the focal length of the system by cutting in or out a group of one or more optical lens groups in the optical path, thereby realizing the conversion of the three fields of view. The advantage of this method is that the optical axis parallelism and optical transmittance of the small field of view are optimal. The disadvantage is that the mechanical structure of the conversion field of view is complex and the time required is long. Because there are moving parts in the system, the optical axis stability is poor. At the same time, the space required for the lens group conversion is large. The axial movement method is to change the focal length of the system by moving one or more optical lens groups forward and backward along the optical axis, thereby realizing the conversion of the three fields of view. The advantage of this method is that the system is small in size and light in weight. The disadvantage is that there are moving parts in the system, the optical axis has a large range of jumps and the field of view conversion time is long. The multi-field coupling method is that multiple field of view optical systems use optical coupling elements to achieve the conversion of the three fields of view through motor-driven shading shields. The advantages of this method are excellent image quality of each field of view, stable performance, easy guarantee of optical axis parallelism, and short field of view conversion time.

[0005] U.S. Patent 7099077 discloses a three-field optical system, which is a catadioptric off-axis structure. All optical elements are reflectors, and the conversion of the three fields of view is achieved by driving in and out three plane reflectors. However, the catadioptric off-axis optical system has the following shortcomings: (1) The reflectors used are all high-order aspheric reflectors, which are difficult to process, have limited detection methods, and are costly; (2) The driven-in and driven-out structure results in a large product volume, and the effect of repetition error on the imaging beam of the catadioptric structure is doubled, so that the parallelism of the optical axis is difficult to ensure; (3) Under high and low temperature conditions, the deformation of the reflector is large, and there is no focusing mechanism, which leads to a significant decrease in the imaging quality of the system; (4) The optical axis of the off-axis structure is difficult to find during the installation and adjustment process, and the installation and adjustment are difficult. The consistency of the optical axes of the three fields of view is poor, and the accuracy is difficult to ensure. Summary of the invention

[0006] (I) Purpose of the invention

[0007] The purpose of the present invention is to provide a three-field compact optical system that takes into account the visible light and near-infrared spectral ranges and enables a vehicle-mounted anti-aircraft gun optoelectronic system television camera to realize observation, aiming and tracking functions during the day.

[0008] (II) Technical solution

[0009] In order to solve the above technical problems, the present invention provides a compact multi-spectral three-field television optical system, which includes three interchangeable optical channels and a filter group, the three optical channels are respectively a small field of view optical channel, a medium field of view optical channel, and a large field of view optical channel;

[0010] The small field of view optical channel includes a small field of view objective lens group, a first focusing objective lens 5, a reflecting prism 6, and a beam splitting cube prism 19 arranged in sequence along the optical path direction. After the light from the external scene enters the small field of view optical channel, it is converged by the small field of view objective lens group and the first focusing objective lens 5, and then successively undergoes two 90° deflections by the reflecting prism 6 and the beam splitting cube prism 19, and then passes through the filter group by transmission and is focused on the CMOS target surface 22;

[0011] The medium field of view optical channel includes a pair of first optical wedges 13, a medium field of view objective lens group, a second focusing objective lens group, and a beam splitting cube prism 19 arranged in sequence along the optical path direction. After the light from the external scene enters the medium field of view optical channel, it is converged by the medium field of view objective lens group and the second focusing objective lens group, and then successively passes through the beam splitting cube prism 19 and the filter group by transmission and is focused on the CMOS target surface 22;

[0012] The large field of view optical channel includes a pair of second optical wedges 7, a large field of view objective lens group, a plane mirror 12, and a beam splitting cube prism 19. After the light from the external scene enters the large field of view optical channel, it is converged by the large field of view objective lens group, and then successively undergoes two 90° deflections by the plane mirror 12 and the beam splitting cube prism 19, and then passes through the filter group by transmission and is focused on the CMOS target surface 22.

[0013] (III) Beneficial Effects

[0014] The compact multi-spectral three-field-of-view television optical system provided by the above technical solution has the beneficial effects reflected in the following aspects:

[0015] (1) The optical elements of each objective lens group are all spherical lenses, and all lens materials are selected from Chinese environmental protection glass, which is easy to process, easy to inspect, and has low cost.

[0016] (2) The small field of view optical channel, the medium field of view optical channel, and the large field of view optical channel share one imaging device through coupling optical elements; the switching between the three channels is realized by changing the positions of the plane mirror and the light shield. The structure of the present invention is relatively simple, has a small volume, and is easy to operate.

[0017] (3) Both the small field of view optical channel and the medium field of view optical channel have focusing mechanisms to compensate for the image plane displacement when the temperature changes.

[0018] (4) The small field of view optical channel, the medium field of view optical channel, and the large field of view optical channel are all axially symmetric transmissive structures, with low alignment difficulty and easy to ensure the optical axis consistency of the three fields of view. Description of the Drawings

[0019] Figure 1 is a schematic diagram of the best embodiment of the compact multi-spectral three-field-of-view television optical system of the present invention.

[0020] Figure 2It is a schematic diagram of the small field of view channel of the compact multi-spectral three-field-of-view television optical system of the present invention.

[0021] Figure 3 It is a schematic diagram of the medium field of view channel in the compact multi-spectral three-field-of-view television optical system of the present invention.

[0022] Figure 4 It is a schematic diagram of the large field of view channel of the compact multi-spectral three-field-of-view television optical system of the present invention. Detailed implementation manners

[0023] To make the objectives, contents and advantages of the present invention clearer, the following further describes in detail the specific implementation manners of the present invention with reference to the drawings and embodiments.

[0024] As Figures 1 to 4 shown, the compact multi-spectral three-field-of-view television optical system of the present invention includes three interchangeable optical channels and a filter set. The three optical channels are respectively a small field of view optical channel, a medium field of view optical channel, and a large field of view optical channel.

[0025] The small field of view optical channel includes a small field of view objective lens group, a first focusing objective lens 5, a reflecting prism 6, and a beam splitting cube prism 19 arranged in sequence along the optical path direction. After the light from the external scene enters the small field of view optical channel, it is converged by the small field of view objective lens group and the first focusing objective lens 5, and then successively undergoes two 90° deflections by the reflecting prism 6 and the beam splitting cube prism 19, and then passes through the filter set and is focused on the CMOS target surface 22.

[0026] The medium field of view optical channel includes a pair of first optical wedges 13, a medium field of view objective lens group, a second focusing objective lens group, and a beam splitting cube prism 19 arranged in sequence along the optical path direction. After the light from the external scene enters the medium field of view optical channel, it is converged by the medium field of view objective lens group and the second focusing objective lens group, and then successively passes through the beam splitting cube prism 19 and the filter set and is focused on the CMOS target surface 22.

[0027] The large field of view optical channel includes a pair of second optical wedges 7, a large field of view objective lens group, a plane mirror 12, and a beam splitting cube prism 19. After the light from the external scene enters the large field of view optical channel, it is converged by the large field of view objective lens group, and then successively undergoes two 90° deflections by the plane mirror 12 and the beam splitting cube prism 19, and then passes through the filter set and is focused on the CMOS target surface 22.

[0028] In the present invention, the optical axes of the small field-of-view optical channel, the medium field-of-view optical channel, and the large field-of-view optical channel are parallel to each other, and the switching between them is achieved by two motors respectively driving the plane mirror 12 and the light shield 23. When the plane mirror 12 is placed perpendicular to the optical axis of the large field-of-view objective lens group and the light shield 23 is located between the second focusing objective lens group and the beam splitter cube prism 19, the present invention is in the working state of the small field-of-view optical channel; when the plane mirror 12 is placed perpendicular to the optical axis of the large field-of-view objective lens group and the light shield 23 is located between the beam splitter cube prism 19 and the reflecting prism 6, the present invention is in the working state of the medium field-of-view optical channel; when the plane mirror 12 is placed at an angle of 45° with the optical axis of the large field-of-view objective lens group and the light shield 23 is located between the second focusing objective lens group and the beam splitter cube prism 19, the present invention is in the working state of the large field-of-view optical channel.

[0029] In addition, to ensure good parallelism among the small field-of-view optical channel, the medium field-of-view optical channel, and the large field-of-view optical channel, a pair of second optical wedges 7 and first optical wedges 13 are respectively arranged in the large field-of-view optical channel and the medium field-of-view optical channel in this embodiment, so as to adjust the parallelism of the three optical channels during the alignment process.

[0030] In this preferred embodiment, the small field-of-view objective lens group includes a first lens group, a third lens 2, a second lens group, and a third lens group arranged in sequence along the optical path direction, and the optical powers are positive, negative, positive, and negative in sequence; the optical power of the first focusing objective lens 5 is negative. The first lens group is composed of a first lens 1-1 and a second lens 1-2 glued together, and the optical powers are negative and positive in sequence; the second lens group is composed of a fourth lens 3-1 and a fifth lens 3-2 glued together, and the optical powers are positive and negative in sequence; the third lens group is composed of a sixth lens 4-1 and a seventh lens 4-2 glued together, and the optical powers are positive and negative in sequence.

[0031] The medium field-of-view objective lens group includes a fourth lens group, a fifth lens group, and a sixth lens group arranged in sequence along the optical path direction, and the optical powers are negative, positive, and positive in sequence; the second focusing objective lens group is composed of a seventh lens group and a seventeenth lens 18, and the optical powers are negative and positive in sequence. The fourth lens group is composed of a ninth lens 14-1 and a tenth lens 14-2 glued together, and the optical powers are positive and negative in sequence; the fifth lens group is composed of an eleventh lens 15-1 and a twelfth lens 15-2 glued together, and the optical powers are positive and negative in sequence; the sixth lens group is composed of a thirteenth lens 16-1 and a fourteenth lens 16-2 glued together, and the optical powers are negative and positive in sequence; the seventh lens group is composed of a fifteenth lens 17-1 and a sixteenth lens 17-2 glued together, and the optical powers are positive and negative in sequence.

[0032] The large field-of-view objective lens group consists of a front group and a rear group. The front group consists of the eighth lens group and the eighteenth lens 9; the rear group consists of the ninth lens group and the tenth lens group, and their optical powers are negative and positive in sequence. The eighth lens group is composed of the eighteenth lens 8-1 and the nineteenth lens 8-2 cemented together, and their optical powers are positive and negative in sequence; the ninth lens group is composed of the twenty-first lens 10-1 and the twenty-second lens 10-2 cemented together, and their optical powers are positive and negative in sequence; the tenth lens group is composed of the twenty-third lens 11-1 and the twenty-fourth lens 11-2 cemented together, and their optical powers are negative and positive in sequence.

[0033] The filter group consists of a visible light filter 20 and a near-infrared filter 21 to achieve the switching between the visible light band (0.45μm - 0.7μm) and the near-infrared band (0.75μm - 0.9μm). The visible light filter 20 is coated with a multilayer film system that transmits 0.45μm - 0.7μm and reflects 0.75μm - 1.15μm, with a reflectivity ρ > 98% and a transmittance τ > 92%; the near-infrared filter 21 is coated with a multilayer film system that transmits 0.75μm - 0.9μm and reflects 0.95μm - 1.15μm, with a reflectivity ρ > 98% and a transmittance τ > 94%.

[0034] The reflecting prism 6 is located between the first focusing objective lens 5 and the beam-splitting cube prism 19, and is used for deflecting the small field-of-view optical path and shortening the axial dimension of the optical path.

[0035] The plane mirror 12 is located between the reflecting prism 6 and the beam-splitting cube prism 19 and is placed at 45° to the optical axis, and is used for deflecting the large field-of-view optical path and shortening the axial dimension of the optical path.

[0036] The beam-splitting cube prism 19 is located in front of the filter group and is used for coupling the three field-of-view optical channels to achieve a common CMOS imaging for the three fields of view; the energy beam-splitting film layer coated on its beam-splitting surface is an anti-reflection film system that transmits 0.45μm - 0.9μm, with a reflectivity ρ > 45% and a transmittance τ > 45%, so as to achieve the balance of the light fluxes of the small, medium, and large fields of view.

[0037] The reflecting prism 6 is a 45° right-angle prism. The reflecting prism 6, the plane mirror 12, and the beam-splitting cube prism 19 are all made of H-K9L environmental protection glass. The visible light filter 20 is made of JB450 colored glass and is coated with an anti-reflection film system that transmits 0.45μm - 0.6μm. The near-infrared filter 21 is made of HB670 colored glass and is coated with a multilayer film system with high reflectivity of 0.85μm - 1.15μm (ρ > 99%) and high transmittance of 0.65μm - 0.8μm (τ > 96%). The main parameters of each field-of-view optical channel are shown in Table 1.

[0038] Table 1 Main parameters of the objective lens group of each field-of-view optical channel

[0039]

[0040]

[0041] In this embodiment, the large field-of-view optical channel adopts a retrofocus optical structure, and its back focal length (110 mm) is much larger than the focal length (60 mm) to achieve coupling with the small and medium field-of-view optical paths. The light from the external scene is diverged by the front group with negative optical power and then converged by the rear group with positive optical power, and is imaged on the target surface of the imaging device.

[0042] The combination of the plane mirror and the light shield is switched in a matching manner to achieve the conversion of the small, medium, and large fields of view. When the plane mirror is placed perpendicular to the optical axis of the large field-of-view objective lens group and the light shield is located between the second focusing objective lens group and the beam splitter cube prism, the present invention is in the working state of the small field-of-view optical channel; when the plane mirror is placed perpendicular to the optical axis of the large field-of-view objective lens group and the light shield is located between the beam splitter cube prism and the reflecting prism, the present invention is in the working state of the medium field-of-view optical channel; when the plane mirror is placed at an angle of 45° with the optical axis of the large field-of-view objective lens group and the light shield is located between the second focusing objective lens group and the beam splitter cube prism, the present invention is in the working state of the large field-of-view optical channel; the optical axes of the large field-of-view optical channel, the medium field-of-view optical channel, and the small field-of-view optical channel are parallel to each other.

[0043] A pair of optical wedges are installed at the front ends of the large field-of-view optical channel and the medium field-of-view optical channel respectively, which is convenient for the alignment and adjustment of the parallelism of the three field-of-view optical axes.

[0044] The first focusing objective lens is driven by a DC motor and moves linearly along the optical axis. When the temperature changes between high and low and the target distance changes, the temperature defocus and image plane deviation of the small field-of-view channel can be compensated by moving the first focusing objective lens forward and backward.

[0045] The second focusing objective lens group is driven by a DC motor and moves linearly along the optical axis. When the temperature changes between high and low and the target distance changes, the temperature defocus and image plane deviation of the medium field-of-view channel can be compensated by moving the second focusing objective lens group forward and backward.

[0046] The three optical channels of the present invention share a CMOS imaging device. When the large field-of-view optical channel is the main optical path, the television camera using the present invention can be used for observing, aiming, and ranging of short-range targets during the day; when the medium field-of-view optical channel is the main optical path, the television camera using the present invention can be used for observing, aiming, and ranging of medium-range targets during the day; when the small field-of-view optical channel is the main optical path, the television camera using the present invention can be used for observing, aiming, and ranging of long-range targets during the day.

[0047] It is not difficult to see that in the present invention, the right-angle reflecting prism 6 in the preferred embodiment can be replaced with a plane mirror at an angle of 45° with the optical axis; the beam-splitting cube prism 19 can be replaced with a plane beam splitter at an angle of 45° with the optical axis; the plane mirror 12 can be replaced with a right-angle reflecting prism; the visible light filter 20 can be replaced with colored glasses such as JB400, JB420, JB470, etc.; the near-infrared filter 21 can be replaced with colored glasses such as HB650, HB685, HB700, HB720, HWB760, etc., thereby forming multiple embodiments.

[0048] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A compact multi-spectral three-field-of-view television optical system, characterized in that, it includes three interchangeable optical channels and a filter set. The three optical channels are a small-field-of-view optical channel, a medium-field-of-view optical channel, and a large-field-of-view optical channel respectively; The small-field-of-view optical channel includes a small-field-of-view objective lens group, a first focusing objective lens (5), a reflecting prism (6), and a beam-splitting cube prism (19) arranged in sequence along the optical path direction. After the light from the external scene enters the small-field-of-view optical channel, it is converged by the small-field-of-view objective lens group and the first focusing objective lens (5), and then successively undergoes two 90° deflections by the reflecting prism (6) and the beam-splitting cube prism (19), and then passes through the filter set and is focused on the CMOS target surface (22); The medium-field-of-view optical channel includes a pair of first optical wedges (13), a medium-field-of-view objective lens group, a second focusing objective lens group, and a beam-splitting cube prism (19) arranged in sequence along the optical path direction. After the light from the external scene enters the medium-field-of-view optical channel, it is converged by the medium-field-of-view objective lens group and the second focusing objective lens group, and then successively passes through the beam-splitting cube prism (19) and the filter set and is focused on the CMOS target surface (22); The large-field-of-view optical channel includes a pair of second optical wedges (7), a large-field-of-view objective lens group, a plane mirror (12), and a beam-splitting cube prism (19). After the light from the external scene enters the large-field-of-view optical channel, it is converged by the large-field-of-view objective lens group, and then successively undergoes two 90° deflections by the plane mirror (12) and the beam-splitting cube prism (19), and then passes through the filter set and is focused on the CMOS target surface (22); The optical axes of the small-field-of-view optical channel, the medium-field-of-view optical channel, and the large-field-of-view optical channel are parallel to each other. The switching between the three optical channels is realized by two motors respectively driving the plane mirror (12) and the light shield (23); when the plane mirror (12) is placed perpendicular to the optical axis of the large-field-of-view objective lens group and the light shield (23) is located between the second focusing objective lens group and the beam-splitting cube prism (19), it is in the working state of the small-field-of-view optical channel; when the plane mirror (12) is placed perpendicular to the optical axis of the large-field-of-view objective lens group and the light shield (23) is located between the beam-splitting cube prism (19) and the reflecting prism (6), it is in the working state of the medium-field-of-view optical channel; when the plane mirror (12) is placed at an angle of 45° with the optical axis of the large-field-of-view objective lens group and the light shield (23) is located between the second focusing objective lens group and the beam-splitting cube prism (19), it is in the working state of the large-field-of-view optical channel.

2. The compact multi-spectral three-field-of-view television optical system according to claim 1, characterized in that, The small field-of-view objective lens group includes a first lens group, a third lens (2), a second lens group, and a third lens group arranged in sequence along the optical path direction, with the optical powers being positive, negative, positive, and negative in sequence; the first focusing objective lens (5) has a negative optical power; the first lens group is composed of a first lens (1-1) and a second lens (1-2) cemented together, with the optical powers being negative and positive in sequence; the second lens group is composed of a fourth lens (3-1) and a fifth lens (3-2) cemented together, with the optical powers being positive and negative in sequence; the third lens group is composed of a sixth lens (4-1) and a seventh lens (4-2) cemented together, with the optical powers being positive and negative in sequence.

3. The compact multi-spectral three-field-of-view television optical system according to claim 2, characterized in that, the medium field-of-view objective lens group includes a fourth lens group, a fifth lens group, and a sixth lens group arranged in sequence along the optical path direction, with the optical powers being negative, positive, and positive in sequence; the second focusing objective lens group is composed of a seventh lens group and an eighteenth lens (18), with the optical powers being negative and positive in sequence; the fourth lens group is composed of a ninth lens (14-1) and a tenth lens (14-2) cemented together, with the optical powers being positive and negative in sequence; the fifth lens group is composed of an eleventh lens (15-1) and a twelfth lens (15-2) cemented together, with the optical powers being positive and negative in sequence; the sixth lens group is composed of a thirteenth lens (16-1) and a fourteenth lens (16-2) cemented together, with the optical powers being negative and positive in sequence; the seventh lens group is composed of a fifteenth lens (17-1) and a sixteenth lens (17-2) cemented together, with the optical powers being positive and negative in sequence.

4. The compact multi-spectral three-field-of-view television optical system according to claim 3, characterized in that, the large field-of-view objective lens group is composed of a front group and a rear group. The front group is composed of an eighth lens group and an eighteenth lens (9); the rear group is composed of a ninth lens group and a tenth lens group, with the optical powers being negative and positive in sequence; the eighth lens group is composed of an eighteenth lens (8-1) and a nineteenth lens (8-2) cemented together, with the optical powers being positive and negative in sequence; the ninth lens group is composed of a twenty-first lens (10-1) and a twenty-second lens (10-2) cemented together, with the optical powers being positive and negative in sequence; the tenth lens group is composed of a twenty-third lens (11-1) and a twenty-fourth lens (11-2) cemented together, with the optical powers being negative and positive in sequence.

5. The compact multi-spectral three-field-of-view television optical system according to claim 4, characterized in that, the filter group includes a visible light filter (20) and a near-infrared filter (21). The visible light filter (20) is coated with a multi-layer film system that transmits 0.45μm - 0.7μm and reflects 0.75μm - 1.15μm, with a reflectivity ρ > 98% and a transmittance τ > 92%; the near-infrared filter (21) is coated with a multi-layer film system that transmits 0.75μm - 0.9μm and reflects 0.95μm - 1.15μm, with a reflectivity ρ > 98% and a transmittance τ > 94%.

6. The compact multi-spectral three-field-of-view television optical system according to claim 5, characterized in that, the reflecting prism (6) is located between the first focusing objective lens (5) and the beam splitting cube prism (19) and is used for deflecting the small field-of-view optical path.

7. The compact multi-spectral three-field-of-view television optical system according to claim 6, characterized in that, the plane mirror (12) is located between the reflecting prism (6) and the beam splitting cube prism (19), and is placed at 45° to the optical axis for deflecting the large field-of-view optical path.

8. The compact multi-spectral three-field-of-view television optical system according to claim 7, characterized in that, the beam splitting cube prism (19) is located before the filter group, and an energy splitting film layer is deposited on its beam splitting surface, which is an anti-reflection film system for transmitting 0.45 μm to 0.9 μm, with a reflectivity ρ > 45% and a transmittance τ > 45%.

9. The compact multi-spectral three-field-of-view television optical system according to claim 8, characterized in that, the reflecting prism (6) is a 45° right-angle prism, and the reflecting prism (6), the plane mirror (12), and the beam splitting cube prism (19) are all made of H-K9L environmental protection glass; the visible light filter (20) is made of JB450 colored glass and is deposited with an anti-reflection film system for transmitting 0.45 μm to 0.6 μm; the near-infrared filter (21) is made of HB670 colored glass and is deposited with a multi-layer film system for highly reflecting 0.85 μm to 1.15 μm and highly transmitting 0.65 μm to 0.8 μm, with a reflectivity ρ > 99% and a transmittance τ > 96%.

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