WO2018076330A1 - Finite conjugate distance optical zoom system with adjustable object distance - Google Patents

Abstract

Disclosed is a finite conjugate distance optical zoom system with an adjustable object distance, comprising an object distance adjusting lens set (2), a variable magnification lens set (3), a compensation lens set (4) and a rear fixing lens set (5) arranged along an optical axis in sequence, wherein the object distance adjusting lens set (2) can move in the direction of the optical axis to clearly image object planes with different object distances on an image plane at fixed positions, to observe the greatly fluctuating object planes without moving the object planes or the entire zoom system.

Description

Finite-distance conjugate distance optical zoom system with adjustable object distance Technical field

The invention relates to the field of optical instruments, in particular to a finite distance conjugate optical zoom system with adjustable object distance.

Background technique

In the development of imaging optical systems, there is a need to use the optical system to search for targets, and to clearly image and identify the details of the target after it is found. In order to meet such demands, an optical system in which the focal length can be changed - a zoom optical system has been developed. Zooming refers to an optical system in which the focal length is continuously changed within a certain range while the image plane position remains unchanged. The purpose of changing the focal length is to continuously change the magnification of the system, such as the size of the scene continuously variable, so that the observer produces a feeling of near and far or far and near. According to the imaging characteristics of the optical system, the optical system with shorter focal length is characterized by large field of view and low resolution; on the contrary, the optical system with longer focal length is characterized by small field of view and high resolution. Because of this, the zoom optical system is particularly suitable for searching for targets with the characteristics of short focal length and large field of view, and then adjusting to a small focal length and small field of view to accurately identify the searched target details.

From the composition of the zoom optical system, the system is generally divided into four parts: a front fixed group, a variable power group, a compensation group, and a rear fixed group. The front fixed group is responsible for constraining the light beam in the large field of view outside, so that the rear light group has a small diameter, and the design and processing are relatively simple. The zoom group is responsible for adjusting the change in focal length to produce the desired focal length. The compensation group is responsible for compensating for the change of the image plane position introduced by the zooming change of the zooming group, and ensuring that the image plane position does not move after the compensation. The rear fixed group is mainly responsible for the correction of the residual aberration to ensure the imaging quality of the optical system during the entire zooming process. The above four optical components are the basic form of the zoom system, and the advanced zoom system is derived from the optimization of the structure.

At present, the development of the zoom optical system is relatively mature, and various commercial zoom systems have appeared on the market. Such as finite distance conjugate distance zoom system, infinity conjugate distance zoom system and so on. Among them, the former is mainly used for the zoom microscope objective system; the latter is mainly used for the zoom camera system and the telephoto system. In the zoom microscope objective system, the object and image plane are fixed, and this zoom system is suitable for most applications. However, for some special scenes, such as large fluctuations in the object surface, or a strong spatial stereoscopic effect, it is not enough for the conventional object and image surface to be fixed. Use, you need to move the object or move the entire zoom objective to achieve clear image of different objects.

In addition, in the zoom system, the moving direction of the compensation group is generally not monotonous along the optical axis direction, but is first moved in one direction, and after reaching an extreme value, then moving in the opposite direction, there is a reverse process. For example, in the process from short focus to telephoto, the compensation group first moves in the negative direction of the optical axis, and there is an extreme point in the direction in the middle. After this extreme point, the compensation group is along the optical axis. Move in the positive direction until the telephoto position is reached. Due to this non-monotonicity, the angle of the zoom becomes larger when the zoom cam curve is designed in the optical machine structure, the processing becomes difficult, and sometimes the stuck or even stuck phenomenon may occur, resulting in damage and burn of the focus motor.

Summary of the invention

In view of the above technical problems, in order to overcome the deficiencies of the above prior art, the present invention proposes a finite distance conjugate optical zoom system with adjustable object distance.

According to an aspect of the present invention, a finite-distance conjugate optical zoom system with adjustable object distance is provided, including a shifting objective lens group, a variator lens group, a compensating mirror group, and a rear fixing mirror sequentially disposed along an optical axis. The group of objects can be moved along the optical axis to clearly image the object surface of different object distances on the image surface of the fixed position.

Preferably, the variator lens group and the compensation mirror group are unidirectionally moved in the optical axis direction during the unidirectional zooming process.

Preferably, the object distance adjustable finite distance conjugate optical zoom system further comprises a shifting distance cam barrel, the side wall of which is provided with a first cam curve extending in a unidirectional spiral along the axial direction of the cam barrel; The adjusting object is disposed from the lens barrel to adjust the object distance mirror group clamp for clamping the object to the mirror group; the adjusting object is provided with a first guiding pin on the mirror group clamp, the first guiding pin Embedding into the first cam curve, the first guiding pin moves along the first cam curve by rotating the adjusting object, and the adjusting object moves the mirror to the mirror The group moves in one direction along the optical axis.

Preferably, the object distance adjustable finite distance conjugate optical zoom system further comprises a zoom compensation cam barrel, the sidewall of which is provided with a second cam curve extending axially in the axial direction along the variable compensation cam barrel and a third cam curve, wherein the variable power compensation cam barrel is provided with a variator lens holder and a compensation mirror group fixture; the variator lens holder clamps the variator lens group, and the second guide pin is disposed thereon a second guide pin embedded in the second cam curve; the compensation mirror set clamp for clamping the compensation mirror group, on which a third guide pin is disposed, and the third guide pin is embedded To the third cam curve; by rotating the variable compensation cam barrel, the second guide pin and the third guide pin move along the second cam curve and the second cam curve, respectively, The double-mirror group fixture and the compensation mirror group fixture respectively drive the variable power mirror group and the compensation mirror group to be unidirectionally linked in the direction of the optical axis in the one-way zooming process.

Preferably, the power of the object from the lens group is a positive value, which includes a positive lens power of the object of the gluing lens group and a positive power of the positive lens.

Preferably, the power of the variator lens group is a negative value, which includes a variable power single lens of negative power and a variable power glue lens group of negative power.

Preferably, the power of the compensation mirror set is a negative value, which is a compensated glue mirror set of negative power.

Preferably, the power of the rear fixed mirror group is a positive value, which includes a post-fixed first single lens of positive power, a post-fixed first glued mirror group of positive power, and a second fixed fixed optical power of negative power A lens, a post-fixed third single lens of positive power, and a post-fixed second glue lens set of positive power.

Preferably, the positive power of the dimming distance from the gluing mirror group includes a negative power of the object to be adjusted from the gluing front lens and the positive power to the gluing lens.

Preferably, the variable power gluing mirror set of negative power includes a variable power gluing front lens of negative power and a variable power gluing lens of positive power.

Preferably, the negative power compensated glued lens set comprises a negative power compensated glued front lens and a positive power compensated glued rear lens.

Preferably, the post-fixed first cemented mirror set of positive power comprises a post-fixed first pre-glue lens of positive power and a post-fixed first glued lens of negative power.

Preferably, the post-fixed second cemented mirror set of positive power is post-fixed by the negative power of the second pre-bonded front lens and the positively fixed second glued rear lens of the positive power.

Preferably, in each of the above cemented lens groups, the pre-glue lens is a glass material having a small Abbe number, and the lens after bonding is a glass material having a large Abbe number, and both Abbe number difference values are greater than 25.

Preferably, the focal length f ₂ of the object from the mirror group is 96 mm to 122 mm, the focal length f ₃ of the variable power lens group is -25 mm to -32 mm, and the focal length f ₄ of the compensation lens group is -25 mm to -42 mm, and the rear fixed mirror group The focal length f ₅ is 24 mm to 32 mm.

Preferably, the focal length f ₂ of the object from the mirror group is 106 mm, the focal length f ₃ of the variable power mirror group is -29.5 mm, the focal length f ₄ of the compensation mirror group is -32.5 mm, and the focal length f ₅ of the rear fixed mirror group is 27.9. Mm.

Preferably, the object distance ranges from 340 mm to 380 mm.

Preferably, the finite distance conjugate optical zoom system includes an image sensor disposed at the image plane position for receiving imaging.

It can be seen from the above technical solutions that the present invention has the following beneficial effects:

The use of the object-to-distance mirror group to achieve a clear observation of the fluctuation of the object surface without moving the object surface or the entire zoom system;

From the short focal length large field of view to the long focal length small field of view or the opposite zooming process, the movement of the compensation group is monotonous along the optical axis direction, and the zoom cam is easy to process;

The object is in collision with the zoom group and the zoom group;

The chromatic aberration is corrected using a cemented lens.

DRAWINGS

1 is a schematic structural view of a finite distance conjugate optical zoom system according to an embodiment of the present invention;

2 is a schematic structural view of a shifting target cam barrel corresponding to the mirror group of FIG. 1;

3 is a schematic structural view of a variable magnification compensation cam barrel corresponding to the variable power mirror group and the compensation mirror group of FIG. 1;

4 is a schematic view showing zooming of the optical zoom system of FIG. 1;

Figure 5 is a schematic view showing the change of the object distance in the short focal position of the optical zoom system of Figure 1;

Figure 6 is a schematic view showing the change of the object distance in the focal position of the optical zoom system of Figure 1;

Figure 7 is a schematic diagram showing the change of the object distance in the telephoto position of the optical zoom system of Figure 1;

Figure 8 (a) - (a) The aberration-field of view of the optical zoom system of Figure 1 at short, medium and telephoto at an object distance of 340 mm;

Figure 9 (a) - 9 (c) The aberration-field of view of the optical zoom system of Figure 1 at short, medium and telephoto at an object distance of 360 mm;

Figure 10 (a) - 10 (c) The aberration-field of view of the optical zoom system of Figure 1 at short, medium and telephoto at an object distance of 380 mm.

[main components]

1-object surface; 2-tuning distance mirror group; 3-variable mirror group; 4-compensation mirror group; 5-post fixed mirror group;

6-adjustment distance cam barrel; 61-first cam curve; 7-variable compensation cam barrel;

71 - second cam curve; 72 - third cam curve.

Detailed ways

Some embodiments of the invention will be described more fully hereinafter with reference to the appended drawings, in which some, but not all, In fact, the various embodiments of the invention can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the invention meets applicable legal requirements.

The present invention will be further described in detail below with reference to the specific embodiments of the invention.

The embodiment of the invention provides a finite-distance conjugate optical zoom system with adjustable object distance, as shown in FIG. 1 , including a mirror set 2, a zoom lens group 3, and compensation arranged in the optical axis direction. The mirror group 4 and the rear fixed mirror group 5, wherein the front fixed mirror group and the rear fixed mirror group are fixed and unadjustable compared to the finite distance conjugate optical zoom system in the prior art, and the shifting distance mirror group in the present invention 2 Relative to the position of the entire finite distance conjugate optical zoom system, when observing the object surface with large fluctuation or strong stereoscopic effect, it is not necessary to move the object surface or move the entire zoom system, only need to adjust the object mirror The position of the group 2 is adjusted to adjust the object distance, and in the observation, the rear fixed mirror group 5 and the image plane of the optical zoom system are fixed in position.

Specifically, as shown in FIG. 1 , the power of the object from the mirror group 2 is a positive value, and the incident angle of the incident beam is constrained, so that the incident angle of the beam entering the variable magnification group 3 is small, and the high order is reduced. Aberration. It consists of a positive-focusing object from the gluing mirror group 21 and a positive-focusing object from the single lens 22, wherein the object of the object from the gluing mirror group 21 is a negative-gravitation object from the gluing front lens 211 and the positive light. The focus of the focus is glued from the glued lens 212. The power of the anamorphic lens group 3 is a negative value, which is composed of a variable power single lens 31 of negative power and a variable power glue lens group 32 of negative power, wherein the variable power gluing mirror group 32 is composed of negative light The zooming front lens 321 of the power and the variable power of the positive power are bonded to the lens 322. The power of the compensation mirror group 4 is a negative value, which is a compensation optical lens group 41 of the negative power, wherein the compensation glue lens group 41 is compensated by the negative refractive power of the pre-bonded front lens 411 and the positive power. The lens 412 is glued together. The power of the rear fixed mirror group 5 is a positive value for correcting the low-order phase difference, which is fixed by the positive fixed power of the first single lens 51, the positive fixed power of the first fixed lens group 52, and the negative optical focus. a post-fixed second single lens 53, a post-fixed third single lens 54 of positive power and a post-fixed second glued lens set 55 of positive power, wherein the rear fixed first glued mirror group 52 is composed of positive power The post-fixed first glued front lens 521 and the negative-gloss post-fixed first glued rear lens 522 are glued; the rear fixed second glued mirror set 55 is negative The post-fixing second pre-molding lens 551 of the power and the post-fixing second gluing lens 552 of the positive power are glued together. The embodiment of the invention uses five sets of glued mirror sets to correct the chromatic aberration of the zoom system.

The optical zoom system of the embodiment of the present invention can realize that the object distance is continuously adjustable within a certain range. In the embodiment of the present invention, it is preferable that clear observation can be realized within a variation range of 40 mm. 2 shows a shifting distance cam barrel 6 for mounting the object from the mirror group 2, on the side wall of the shifting cam barrel 6, a cam curve 61 corresponding to the mirror group 2 is provided, the cam curve 61 is axially unidirectionally spirally extended on the side wall of the cam barrel 6 in the axial direction, and the object of the mirror group 2 is mounted in the shifting cam barrel 6 by the mirror assembly clamp, and the first guide pin on the clamp Inserted into the cam curve 61, the first guide pin on the clamp can be slid along the cam curve 61 by rotating the adjustment target from the cam barrel 6, so that the object is controlled from the mirror group 2 in the axial direction of the cam barrel 6 Move continuously. When the optical zoom system of the present invention is used for observation, the relative position between the object to the cam barrel 6 and the object to be observed remains fixed, and the position of the object to be observed can be changed by adjusting the position of the lens group 2 within the cam barrel 6. The object distance is such that the observation fluctuations are very large or the three-dimensional feeling is strong.

According to the embodiment of the present invention, the movement of the object from the mirror group 2 in the shifting target cam barrel 6 can be realized by rotating the shifting object from the cam barrel 6 by an electric motor, or by rotating the shifting target cam barrel 6 manually. achieve.

In the embodiment of the present invention, FIG. 3 shows a zoom compensation cam barrel 7 for mounting the variable power mirror group 3 and the compensation mirror group 4. The variable power mirror group 3 and the compensation mirror group 4 are collectively disposed on the zoom compensation cam barrel. In the seventh embodiment, the variator lens group 3 is used to adjust the change of the focal length of the zoom system, and the compensation mirror group 4 is used to compensate for the change of the image plane position caused by the focusing of the variator lens group 3, so as to ensure that the image plane position is always fixed. The anamorphic lens group 3 and the compensation mirror group 4 need to be linked together to achieve variable magnification focusing that maintains the position of the image plane. 3 shows a zoom compensation cam barrel 7 for mounting the anamorphic mirror group 3 and the compensation mirror group 4, on the side wall of the variable magnification compensation cam barrel 7, a cam curve 71 corresponding to the anamorphic mirror group 3 is provided, And corresponding to the cam curve 72 of the compensation mirror group 4, both cam curves are axially unidirectionally spirally extended along the variable compensation cam barrel 7.

The variable power mirror group 3 and the compensation mirror group 4 are respectively mounted in the variable magnification compensation cam barrel 7 through the variable power mirror group clamp and the compensation mirror group clamp, and the second guide pin and the compensation mirror group clamp on the variable magnification mirror assembly The third guide pins are respectively embedded in the cam curve 71 and the cam curve 72. Through the variable compensation cam barrel 7, the guide pins on the two clamps can be respectively slid along the cam curve 71 and the cam curve 72, thereby causing the variator lens group 3 and The compensation mirror group 4 is along the axis in the variable compensation cam barrel 7 Continuously move forward and backward. In this embodiment, both the cam curve 71 and the cam curve 72 are axially unidirectionally extended along the axial direction of the zoom compensation cam barrel 7, and the cam curve is simply processed, and the cam curve is used to change the zoom system from telephoto to short focus. In the process of changing from short focus to telephoto, both the anamorphic lens group 3 and the compensation mirror group 4 are unidirectionally moved in the axial direction of the cam barrel 7. The calculation formula of the rising angle of the cam curve 71 and the cam curve 72 is as shown in the formula (1).

In the formula (1), α is the rising angle, ΔZ is the axial displacement amount of the cam curve, Δθ is the circumferential rotation angle of the cam curve, and R is the cam barrel radius.

In the preferred embodiment of the present invention, the cam curve 71 has an elevation angle of 26.68°, and the cam curve 72 has an elevation angle of 2.6°, which is less than the limit value of 45°, thereby avoiding the sticking or even jamming of the lens group during the moving process. To prevent the focus motor from being damaged due to the lens being stuck.

According to the embodiment of the present invention, the interlocking movement of the anamorphic lens group 3 and the compensation mirror group 4 in the variable compensation cam barrel 7 can be realized by the electric motor rotating zoom compensation cam barrel 7, or can be rotated manually by a manual method. The compensation cam barrel 7 is realized.

In the embodiment of the present invention, in order to ensure that the light can be stably transmitted in the optical zoom system without significant inflection points without generating a large high-level aberration, the combined focal length value f _{2 of the} object to the mirror group 2 can be selected from the range of 96mm ~ 122mm, preferably 106mm; the combined focal length value f _{3 of the} variable power mirror group 3 can be selected from -25mm to -32mm, preferably -29.5mm; the combined focal length value f _{4 of the} compensating mirror set 4 is selectable -25 mm to -42 mm, preferably -32.5 mm; the combined focal length value f _{5 of the} rear fixed mirror group 5 is optionally in the range of 24 mm to 32 mm, preferably 27.9 mm. The invention can realize the variation of each mirror group in the focal length range by changing parameters such as the radius of curvature and the thickness of the single lens in the lens groups.

In the embodiment of the invention, the optical components in each mirror group adopt spherical surfaces, which reduces the cost of optical processing and detection while ensuring better imaging quality.

The values of the optical element parameters in each lens group of the preferred embodiment of the present invention are as shown in Table 1. In the table, r represents the radius of curvature, d represents the distance between lenses or the thickness of the lens, and n _d represents the refractive index of d light ( d light refers to visible light having a wavelength of 588 nm, which is commonly used as a reference light for evaluating an optical system, and v represents an Abbe number of a lens, and units of all lengths are calculated in mm.

Table 1

Surface number	Radius of curvature (r)	Distance (d)	Refractive index (n d )	Abbe number (v)
Object	∞	340
1	134.900	3.5	1.75520	27.5
2	65.610	17.57	1.48749	70.4
3	-399.903	0.6
4	68.709	9.35	1.71300	53.8
5	190.543	A
6	314.228	2	1.71300	53.8
7	22.126	12.5
8	-68.370	2.17	1.55200	63.3
9	28.050	7	1.75520	27.5
10	349.710	B
11	-26.430	2	1.69680	55.5
12	18.155	2.24	1.75520	27.5
13	103.146	C
15	-1452.910	3.03	1.51640	64.2
16	-28.444	0.6
17	69.340	5.63	1.48749	70.4
18	-18.500	1.5	1.75520	27.5
19	-63.530	4.3
20	124.965	2	1.48749	70.4
twenty one	60.260	2.46
twenty two	-591.000	3.66	1.48749	70.4
twenty three	-43.376	0.6
twenty four	82.410	2	1.75520	27.5
25	44.681	4.98	1.61309	60.5
26	-55.919	60.25
Image plane	∞	0

As shown in Table 1, the object is adjusted from the lens group to the mirror group 21, and the front lens 211 of the mirror lens group is a glass material with a small Abbe number, and the lens lens 212 is used for the rear lens 212 of the lens group. The number of glass materials, the glue of the two materials can correct the chromatic aberration. Similarly, the variable-folding gluing mirror group 32, the compensation group gluing mirror group 41, the rear fixing group first gluing mirror group 52 and the rear fixing group second gluing mirror group 55 are also selected by using a glass material having a large difference in Abbe number. In order to correct the chromatic aberration. In the five sets of glue mirrors, the Abbe number difference of each set of glue mirrors needs to be greater than 25, and is not limited to the specific values shown in Table 1.

Among them, A, B, and C are the adjustment object to the mirror group 2 and the variable power mirror group 3, the variable power mirror group 3 and compensation The distance between the mirror group 4, the compensation mirror group 4 and the fixed mirror group 5.

In the finite distance conjugate optical zoom system with adjustable object distance according to the embodiment of the present invention, the fixed mirror group 5 and the image surface are fixed during the adjustment of the object distance or the zooming. An image sensor such as a CCD or the like can be used to receive the image at the image plane.

Fig. 4 is a view showing three zoom positions of the zoom optical system of the present invention, and Table 2 shows the distance between the mirror groups at the three zoom positions of the zoom optical system of the present invention. Taking the object distance of 340mm as an example, as can be seen from FIG. 4 and Table 2, when the zoom optical system performs zooming observation on a fixed object surface 1 to obtain an enlarged or reduced image there, the position of the object to be adjusted from the mirror group 2 remains unchanged. The variator group 3 and the compensation mirror group 4 are unidirectionally moved in the optical axis direction. Taking the short focal position to the telephoto position as an example, the anamorphic mirror group 3 and the compensating mirror group 4 are unidirectionally moved from the object toward the image plane direction along the optical axis.

Table 2

spacing	Short focus position	Center focal position	Telephoto position
A (mm)	4.5	44.4	57.9
B(mm)	59.83	17.43	3
C(mm)	2	4.45	5.52

5-7 are schematic diagrams showing the adjustment of the object distance in the three zoom positions of the zoom optical system of the present invention, and Table 3 shows the zoom lens system of the present invention at three object positions at three zoom positions. 2 The distance A between the variator group 3. In any zoom position, in view of the large fluctuation of the object surface or the strong stereoscopic effect, a clear image can be obtained by moving the object to the mirror group 2, at which time the variator lens group 3 and the compensation mirror group 4 remain stationary. As shown in Table 3, taking the short focal position as an example, in view of the fluctuation of the object faces 11, 12, 13, when the object distance is changed from 340 mm to 360 mm and then to 380 mm, the variator lens group 3 and the compensation mirror group 4 Keep moving, by moving the object to the mirror group 2, change the distance between the object to the mirror group 2 and the zoom lens group 3, from 4.5mm to 4.4mm, then to 2.4mm, in the same image Get a clear image. Although Table 3 only shows the distance between the object group 2 and the variator lens group 3 when the object distance is 340 mm, 360 mm and 380 mm, those skilled in the art can understand that in the present invention, the object distance can be Continuously change between 340mm and 380mm, which is determined by the fluctuation of the object surface. When the object distance is between 340mm and 380mm, the object can be moved from the mirror group 2 to change the object distance to the mirror group 2. The distance from the anamorphic lens group 3 acquires a clear image on the same image plane. The above only uses the short focal position as an example. When the zoom optical system is in the mid-focus position or the telephoto position, the fluctuation of the object surface is large or the stereoscopic effect is strong. To get a clear image, change at this time The double lens group 3 and the compensation lens group 4 are kept stationary. At this time, the distance between the object lens group 2 and the power variator lens group 3 is as shown in Table 3, and will not be explained here.

table 3

Object distance (mm)	340	360	380
Short focus position A (mm)	4.5	4.4	2.4
Center focal position A (mm)	44.4	40.6	37.3
Telephoto position A (mm)	57.9	54.3	51.2

It can be determined from Table 3 that, in the short focal position, the stroke of the object from the mirror group 2 is 4.5-2.4=2.1 mm, and in the middle focal position, the stroke of the object to the mirror group 2 is 44.4-37.3=7.1 mm. In the telephoto position, the stroke of the object to the mirror group 2 is 57.9-51.8=6.1 mm. It can be seen that the axial movement distance of the object from the mirror group 2 is different at different focal lengths, and the axial movement distance of the object from the mirror group 2 is different. The maximum range is 7.1mm, which is feasible when designing cam curves.

The adjustment object from the mirror group 2 and the variable power mirror group 3 respectively have independent cam mechanisms, and do not interfere with each other. It can be seen from Fig. 5 that during the process of changing the object distance from 340 mm to 380 mm, the object is always monotonously moved toward the image plane, that is, when the object distance is 380 mm, the object is adjusted from the lens group 2 and zoomed. The distance of the mirror group 3 is the closest, as shown in Table 2, and in the short focal position, the distance is 2.4 mm, and the two cam mechanisms do not interfere with each other. As can be seen from Table 3, at the mid-focus and telephoto positions, the distance between the object to the mirror group 2 and the variable magnification group 3 is larger, and interference is unlikely to occur.

8(a)-8(c) respectively show aberration-field of view curves at three zoom positions when the optical zoom system of the embodiment of the present invention is at an object distance of 340 mm, Figs. 9(a)-9( c) respectively showing aberration-field of view curves at three zoom positions when the object distance is 360 mm, and FIGS. 10(a)-10(c) respectively show the present invention. The optical zoom system of the embodiment has an aberration-field of view curve at three zoom positions at an object distance of 380 mm. As can be seen from the aberration curves in the figure, the image quality of the optical system of this embodiment has been well corrected.

In the optical zoom system of the embodiment of the present invention, when observing an object surface with a large fluctuation or a strong stereoscopic effect, the object distance can be changed from 340 mm to 380 mm by moving the object to the lens group, and the entire zoom does not need to be moved. The system can obtain a clear image-fixed image, and the optical zoom system in the present invention is not limited to the specific value and range of the above object distance.

It should be noted that the shapes and dimensions of the various components in the drawings do not reflect the true size and proportion, but only The content of the embodiments of the present invention is intended.

The directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are merely referring to the directions of the drawings, and are not intended to limit the invention. protected range. The above embodiments may be used in combination with other embodiments or based on design and reliability considerations, that is, the technical features in different embodiments may be freely combined to form more embodiments.

It should be noted that the implementations that are not shown or described in the drawings or the text of the specification are all known to those of ordinary skill in the art and are not described in detail. In addition, the above definitions of the various elements and methods are not limited to the specific structures, shapes or manners mentioned in the embodiments, and those skilled in the art can simply modify or replace them.

For example, aspherical optics can be used in each mirror instead of spherical optics.

The specific embodiments of the present invention have been described in detail in the foregoing detailed description of the embodiments of the present invention. All modifications, equivalents, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims (11)

1. A finite-distance conjugate optical zoom system with adjustable object distance, characterized in that it comprises a mirror set (2), a variable power mirror group (3) and a compensating mirror group (4) arranged in sequence along the optical axis. ) and rear fixed mirror set (5);

   The object to be moved from the mirror group (2) can be moved along the optical axis direction to clearly image the object surface of different object distances on the image surface of the fixed position.
2. The finite-distance conjugate optical zoom system according to claim 1, wherein the variator lens group (3) and the compensating mirror group (4) are unidirectionally moved in the optical axis direction during the unidirectional zooming process.
3. The finite-distance conjugate optical zoom system of claim 1 further comprising:

   a shifting cam barrel (6), the side wall of which is provided with a first cam curve (61) extending axially unidirectionally from the cam barrel (6);

   The adjusting object is disposed in the cam cylinder (6) from the mirror assembly clamp for clamping the object to the mirror group (2);

   The shifting objective lens holder is provided with a first guiding pin, the first guiding pin is embedded in the first cam curve (61), and by rotating the adjusting object from the cam barrel (6), The first guiding pin moves along the first cam curve (61), and the adjusting object moves the adjusting object from the mirror group (2) to move in one direction along the optical axis direction.
4. The finite-distance conjugate optical zoom system of claim 1 further comprising:

   a zoom compensation cam barrel (7) having a second cam curve (71) and a third cam curve (72) extending axially in the axial direction along the variable compensation cam barrel (7) The variable magnification compensation cam barrel (7) is provided with a variable power mirror group fixture and a compensation mirror group fixture;

   The variator lens holder clamps the variator group (3), on which a second guide pin is disposed, and the second guide pin is embedded in the second cam curve (71);

   The compensation mirror group fixture is configured to clamp the compensation mirror group (4), and a third guide pin is disposed thereon, and the third guide pin is embedded in the third cam curve (72);

   Wherein, by rotating the variable compensation cam barrel (7), the second guide pin and the third guide pin move along the second cam curve (71) and the second cam curve (72), respectively. The variable power mirror group fixture and the compensation mirror group fixture respectively drive the variable power mirror group (3) and the compensation mirror group (4) to be unidirectionally linked along the optical axis direction in the one-way zooming process.
5. The finite distance conjugate optical zoom system according to claim 1, wherein

   The power of the object from the mirror group (2) is positive, which includes the positive power of the object from the glue lens group (21) and the positive power of the single lens (22); and/or

   The power of the variator group (3) is a negative value, which includes a variable power single lens (31) of negative power and a variable power glue lens group (32) of negative power; and/or

   The power of the compensation lens group (4) is a negative value, which is a negative refractive power compensation glue mirror group (41); and/or

   The power of the rear fixed mirror group (5) is a positive value, which includes a post-fixed first single lens (51) of positive power, a rear fixed first glue mirror group (52) of positive power, and negative power. The rear fixed second single lens (53), the positive fixed third single lens (54) of positive power, and the rear fixed second glued mirror set (55) of positive power.
6. A finite distance conjugate optical zoom system according to claim 5, wherein

   The positive power of the adjustment of the distance from the gluing mirror set (21) includes a negative power of the object of the pre-glue lens (211) and a positive power of the object of the gluing lens (212); and/or

   The negative power colloidal mirror group (32) includes a negative power pre-gluing front lens (321) and a positive power zooming lens (322); and/or

   The negative power compensation gluing mirror set (41) includes a negative refractive power compensation glued front lens (411) and a positive power compensated glued rear lens (412); and/or

   The post-fixed first cemented mirror set (52) of positive power includes a post-fixed first pre-glue lens (521) of positive power and a post-fixed first glued lens (522) of negative power; and / or

   The post-fixed second cemented mirror set (55) of the positive power is post-fixed with a second pre-bonded front lens (551) and a positively fixed second glued rear lens (552).
7. The finite-distance conjugate optical zoom system according to claim 6, wherein in each of the cemented lens groups, the pre-glue lens is a glass material having a small Abbe number, and the lens after bonding is a glass material having a large Abbe number. The difference between the two Abbe numbers is greater than 25.
8. The finite distance conjugate optical zoom system according to claim 1, wherein the focal length f ₂ of the object to the mirror group (2) is 96 mm to 122 mm, and the focal length f _{3 of the} variable power mirror group (3) The focal length f ₄ of the compensation mirror group (4) is -25 mm to -42 mm, and the focal length f ₅ of the rear fixed mirror group (5) is 24 mm to 32 mm.
9. The finite distance conjugate optical zoom system according to claim 5, characterized in that the focal length f ₂ of the object from the mirror group (2) is 106 mm, and the focal length f ₃ of the variable power mirror group (3) is - 29.5 mm, the focal length f ₄ of the compensation mirror group (4) is -32.5 mm, and the focal length f ₅ of the rear fixed mirror group (5) is 27.9 mm.
10. The finite distance conjugate optical zoom system according to claim 1, wherein said object distance ranges from 340 mm to 380 mm.
11. The finite-distance conjugate optical zoom system of claim 1 further comprising:

    An image sensor is disposed at the image plane position for receiving imaging.

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