Zoom telescope

Abstract

The zoom telescope comprises an objective lens group, a prism group and an eyepiece group which are sequentially arranged along the direction of an optical axis, and the eyepiece group comprises an eyepiece compensation group, an eyepiece zoom group and an eyepiece fixing group which are sequentially arranged; the focal lengths of all the lens groups meet the following conditional expressions:-1.4 < F31 / F32 <-0.9; f33 / F32 is more than 1.2 and less than 1.7; and the eyepiece zoom group and the eyepiece compensation group can be close to each other or far away from each other along the optical axis direction so as to realize the continuous change of the magnification between 60 and 20. According to the zoom telescope, the eyepiece zoom group and the eyepiece compensation group get close to each other or get away from each other in the optical axis direction, so that the magnification of the zoom telescope can be continuously adjusted, and the requirements of different observation objects can be met; and on the premise of realizing the function, high resolution of a view field center and a large view field is realized, clear imaging can be seen, and the system has the advantages of small product size, light weight, low price and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, in particular to a variable-magnification telescope. Background Art

[0002] A variable-power telescope is an optical instrument that can change the field of view by adjusting the magnification. When the magnification is low, the field of view is wider and the objects seen are smaller; when the magnification is increased, the field of view is smaller, but the objects seen are larger and the details are clearer. Variable-power telescopes have a wide range of applications and can be used for astronomical observation, outdoor adventures, military reconnaissance, bird watching, etc.

[0003] However, existing variable-magnification telescopes have the disadvantages of low resolution and poor user experience. Utility Model Content

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of low resolution and poor user experience of variable magnification telescopes in the prior art, thereby providing a variable magnification telescope.

[0005] In order to solve the above technical problems, the technical solution of the utility model is as follows:

[0006] A variable-magnification telescope comprises an objective lens group, a prism group and an eyepiece group which are sequentially arranged along an optical axis direction;

[0007] The objective lens group comprises a first objective lens with positive focal power, a second objective lens with negative focal power, a third objective lens with positive focal power, and a fourth objective lens with negative focal power, which are sequentially arranged from the object side to the observation side along the optical axis direction;

[0008] The eyepiece assembly comprises a first eyepiece lens with negative optical power, a second eyepiece lens with positive optical power, a third eyepiece lens with negative optical power, a fourth eyepiece lens with positive optical power, a fifth eyepiece lens with positive optical power, a sixth eyepiece lens with negative optical power, a seventh eyepiece lens with positive optical power, and an eighth eyepiece lens with negative optical power, which are sequentially arranged along the optical axis from the object side to the observation side;

[0009] The first eyepiece lens and the second eyepiece lens constitute an eyepiece compensation group; the third eyepiece lens, the fourth eyepiece lens, the fifth eyepiece lens, and the sixth eyepiece lens constitute an eyepiece variable magnification group; the seventh eyepiece lens and the eighth eyepiece lens constitute an eyepiece fixed group; the focal lengths of all lens groups satisfy the following conditional formula:

[0010] -1.4<F 31 / F 32 <-0.9;

[0011] 1.2<F 33 / F 32<1.7;

[0012] Among them, F 31 is the combined focal length of the eyepiece compensation group, F 32 is the combined focal length of the eyepiece zoom group, F 33 is the combined focal length of the fixed group of eyepieces;

[0013] The magnification of the variable-power telescope is F1 / F3, 20<F1 / F3<60; wherein F1 is the combined focal length of the objective lens group, and F3 is the combined focal length of the eyepiece group; the eyepiece variable-power group and the eyepiece compensation group can approach or move away from each other along the optical axis direction to achieve a continuous change of the magnification between 60-20.

[0014] Furthermore, the prism group includes a first right-angle prism, a second right-angle prism and a half pentaprism which are arranged in sequence from the object side to the observation side along the optical axis; the half pentaprism is used to change the direction of the optical axis.

[0015] Furthermore, at least one of the first right-angle prism and the second right-angle prism is movably arranged along the optical axis; focusing is achieved by moving the first right-angle prism and / or the second right-angle prism.

[0016] Furthermore, the side surfaces where the second lens of the objective lens and the third lens of the objective lens are glued together; the side surfaces where the first lens of the eyepiece and the second lens of the eyepiece are glued together; the side surfaces where the third lens of the eyepiece and the fourth lens of the eyepiece are glued together; the side surfaces where the fifth lens of the eyepiece and the sixth lens of the eyepiece are glued together; and the side surfaces where the seventh lens of the eyepiece and the eighth lens of the eyepiece are glued together.

[0017] Furthermore, when the eyepiece zoom group moves along the optical axis, the eyepiece compensation group moves in the opposite direction along the optical axis.

[0018] Furthermore, a protective glass (30) is provided on a side of the eyepiece assembly close to the prism assembly.

[0019] Furthermore, the aperture of the first lens of the objective lens ranges from 70 to 90 mm.

[0020] Furthermore, when the magnification of the variable-power telescope changes between 60 times and 20 times, the exit pupil diameter of the variable-power telescope changes within the range of 1.5 mm to 4 mm.

[0021] Furthermore, the pupil distance of the variable-power telescope is 16-20 mm.

[0022] Furthermore, the total weight of the variable-power telescope does not exceed 1500 g, and the total optical length does not exceed 400 mm.

[0023] The technical solution of the utility model has the following advantages: by moving the eyepiece zoom group and the eyepiece compensation group closer to or farther away from each other along the optical axis, the magnification of the zoom telescope can be continuously adjusted to meet the needs of different observation objects; and under the premise of realizing this function, high resolution of the center of the field of view and the large field of view can be achieved, and clear imaging can be seen, and the product has the advantages of small size, light weight, and low price. In addition, the zoom telescope realizes internal focusing through a right-angle prism, and can maintain stable imaging when used at different object distances. Multiple groups of cemented lenses and low-dispersion glass can greatly reduce chromatic aberration. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 1 is an optical structure diagram of the variable-magnification telescope in an embodiment of the present invention when the magnification is 60X.

[0026] Explanation of the accompanying reference numerals: 1, objective lens group; L1I, first objective lens; L12, second objective lens; L13, third objective lens; L14, fourth objective lens; 2, prism group; L2I, first right-angle prism; L22, second right-angle prism; L23, half pentaprism; 3, eyepiece group; L30, protective glass; L3I, first eyepiece lens; L32, second eyepiece lens; L33, third eyepiece lens; L34, fourth eyepiece lens; L35, fifth eyepiece lens; L36, sixth eyepiece lens; L37, seventh eyepiece lens; L38, eighth eyepiece lens. DETAILED DESCRIPTION

[0027] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] The embodiment of the present invention provides a variable magnification telescope for realizing flexible changes in different magnifications, and can see clear images under the premise of realizing this function, and has the advantages of small device size, light weight, low price, etc.

[0030] refer to Figure 1 As shown, a variable-magnification telescope comprises an objective lens group 1, a prism group 2, and an eyepiece group 3 which are sequentially arranged from the object side to the observation side along the optical axis.

[0031] The objective lens group 1 includes a first objective lens L11 with positive focal power, a second objective lens L12 with negative focal power, a third objective lens L13 with positive focal power, and a fourth objective lens L14 with negative focal power, which are arranged in sequence from the object side to the observation side along the optical axis.

[0032] The prism group includes a first right angle prism L21, a second right angle prism L22 and a half pentaprism L23 which are arranged in sequence from the object side to the observation side along the optical axis. The half pentaprism L23 can change the direction of the optical axis, which is not only convenient for observation, but also helps to shorten the total length of the finished variable magnification telescope.

[0033] The eyepiece group includes a protective glass L30, which is arranged in sequence from the object side to the observation side along the optical axis direction, a first eyepiece lens L31 with negative focal power, a second eyepiece lens L32 with positive focal power, a third eyepiece lens L33 with negative focal power, a fourth eyepiece lens L34 with positive focal power, a fifth eyepiece lens L35 with positive focal power, a sixth eyepiece lens L36 with negative focal power, a seventh eyepiece lens L37 with positive focal power, and an eighth eyepiece lens L38 with negative focal power. Among them, the first eyepiece lens L31 and the second eyepiece lens L32 constitute an eyepiece compensation group 31; the third eyepiece lens L33, the fourth eyepiece lens L34, the fifth eyepiece lens L35, and the sixth eyepiece lens L36 constitute an eyepiece zoom group 32; the seventh eyepiece lens L37 and the eighth eyepiece lens L38 constitute an eyepiece fixed group 33.

[0034] The focal lengths of all lens groups satisfy the following condition:

[0035] -1.4<F 31 / F 32<-0.9;

[0036] 1.2<F 33 / F 32 <1.7;

[0037] Among them, F 31 is the combined focal length of the eyepiece compensation group (31), F 32 is the combined focal length of the eyepiece zoom group (32), F 33 is the combined focal length of the eyepiece fixed group (33).

[0038] The magnification of the variable-power telescope is F1 / F3, 20<F1 / F3<60, where F1 is the combined focal length of the objective lens group 1, and F3 is the combined focal length of the eyepiece group 3. When the magnification of the variable-power telescope is 60, F1 / F3=60; when the magnification of the variable-power telescope is 20, F1 / F3=20.

[0039] The eyepiece zoom group 32 and the eyepiece compensation group 31 can be moved closer to or farther away from each other along the optical axis to achieve a change in the magnification of the zoom telescope, and can achieve a continuous change between 60 and 20 times of the telescope.

[0040] In this embodiment, the side surfaces of the objective lens second lens L12 and the objective lens third lens L13 are glued together; the side surfaces of the eyepiece first lens L31 and the eyepiece second lens L32 are glued together; the side surfaces of the eyepiece third lens L33 and the eyepiece fourth lens L34 are glued together; the side surfaces of the eyepiece fifth lens L35 and the eyepiece sixth lens L36 are glued together; the side surfaces of the eyepiece seventh lens L37 and the eyepiece eighth lens L38 are glued together. The gluing of positive and negative lenses can greatly improve the chromatic aberration problem of the zoom telescope. At the same time, the total length of the overall optical system is shortened after the lenses are glued.

[0041] When the eyepiece zoom group 32 moves along the optical axis, the eyepiece compensation group 31 moves in the opposite direction along the optical axis to offset the image plane movement caused by the movement of the eyepiece zoom group 32, thereby achieving a continuous change of magnification of 20-60 times. When the distance between the eyepiece zoom group 32 and the eyepiece compensation group 31 increases, the combined focal length F3 of the eyepiece group 3 gradually becomes shorter, the combined focal length F1 of the objective lens group 1 remains unchanged, the magnification of the zoom telescope increases, and the objects seen are larger; when the distance between the eyepiece zoom group 32 and the eyepiece compensation group 31 decreases, the combined focal length F3 of the eyepiece group 3 gradually becomes longer, the combined focal length F1 of the objective lens group 1 remains unchanged, the magnification of the zoom telescope decreases, the objects seen are smaller, but the field of view is wider.

[0042] At least one of the first right-angle prism L21 and the second right-angle prism L22 in the prism set 2 is movable along the optical axis; for example, the first right-angle prism L21 can move forward and backward along the optical axis, thereby changing the total optical length in the optical axis direction to achieve focusing. However, since the right-angle prism itself has the function of folding the optical path and changing the direction of the optical path, even if the prism moves forward and backward, the total length of the product will not change.

[0043] The aperture range of the first objective lens L11 of the variable-magnification telescope is 70-90 mm.

[0044] When the magnification of the variable power telescope changes between 60 times and 20 times, the exit pupil diameter of the variable power telescope changes within the range of 1.5mm-4mm, and the exit pupil distance of the variable power telescope changes within the range of 16-20mm. The longer exit pupil distance makes it easier for different groups of people to use.

[0045] The total weight of the finished variable-magnification telescope does not exceed 1500g, and the total optical length does not exceed 400mm. This lightweight and small variable-magnification telescope improves the portability of the product.

[0046] Table 1 below lists the actual parameters of each lens of this embodiment that conform to the above mathematical relationship:

[0047]

[0048]

[0049] Table 1

[0050] When the zoom telescope changes from 60X to 20X, the air space parameters change as shown in Table 2:

[0051] 60 times 20 times D(10) 2.38 14.32 D(13) 52.06 9.09 D(19) 3.00 34.03

[0052] Table 2

[0053] In Table 2, D(10) is the central air space between the eyepiece first lens L31 and the protective glass L30 in the optical axis direction; D(13) is the central air space between the eyepiece second lens L32 and the eyepiece third lens L33 in the optical axis direction; and D(19) is the central air space between the eyepiece sixth lens L36 and the eyepiece seventh lens L37 in the optical axis direction.

[0054] To sum up, this variable magnification telescope has the following advantages:

[0055] First, it achieves high resolution in the center of the field of view and in the large field of view. It also uses multiple groups of cemented lenses and low-dispersion glass to greatly reduce chromatic aberration.

[0056] Secondly, by moving the eyepiece zoom group 32 and the eyepiece compensation group 31 closer to or farther away from each other along the optical axis, the magnification of the zoom telescope can be continuously adjusted to meet the needs of different observation objects;

[0057] Third, the zoom telescope achieves internal focusing through a right-angle prism, which can maintain stable imaging at different object distances;

[0058] Fourthly, the variable-magnification telescope greatly shortens the total length of the optical system through reasonable lens arrangement, thereby reducing the weight of the finished product and bringing great convenience to the user.

[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. A variable-magnification telescope, characterized in that: It comprises an objective lens group (1), a prism group (2) and an eyepiece group (3) which are arranged in sequence along the optical axis direction; The objective lens group (1) comprises a first objective lens (L11) with positive focal power, a second objective lens (L12) with negative focal power, a third objective lens (L13) with positive focal power, and a fourth objective lens (L14) with negative focal power, which are arranged in sequence from the object side to the observation side along the optical axis. The eyepiece group (3) comprises a first eyepiece lens (L31) with negative focal power, a second eyepiece lens (L32) with positive focal power, a third eyepiece lens (L33) with negative focal power, a fourth eyepiece lens (L34) with positive focal power, a fifth eyepiece lens (L35) with positive focal power, a sixth eyepiece lens (L36) with negative focal power, a seventh eyepiece lens (L37) with positive focal power, and an eighth eyepiece lens (L38) with negative focal power, which are arranged in sequence from the object side to the observation side along the optical axis. The eyepiece first lens (L31) and the eyepiece second lens (L32) constitute an eyepiece compensation group (31); the eyepiece third lens (L33), the eyepiece fourth lens (L34), the eyepiece fifth lens (L35), and the eyepiece sixth lens (L36) constitute an eyepiece variable magnification group (32); the eyepiece seventh lens (L37) and the eyepiece eighth lens (L38) constitute an eyepiece fixed group (33); the focal lengths of all lens groups satisfy the following conditional formula: -1.4<F 31 / F 32 <-0.9; 1.2<F 33 / F 32 <1.7; Among them, F 31 is the combined focal length of the eyepiece compensation group (31), F 32 is the combined focal length of the eyepiece zoom group (32), F 33 is the combined focal length of the eyepiece fixed group (33); The magnification of the variable-power telescope is F1 / F3, 20<F1 / F3<60; wherein F1 is the combined focal length of the objective lens group (1), and F3 is the combined focal length of the eyepiece group (3); the eyepiece variable-power group (32) and the eyepiece compensation group (31) can be moved closer to or farther from each other along the optical axis to achieve a continuous change in the magnification between 60 and 20.

2. The variable power telescope according to claim 1, characterized in that: The prism group (2) comprises a first right-angle prism (L21), a second right-angle prism (L22) and a half pentaprism (L23) which are arranged in sequence from the object side to the observation side along the optical axis; the half pentaprism (L23) is used to change the direction of the optical axis.

3. The variable power telescope according to claim 2, characterized in that: At least one of the first right-angle prism (L21) and the second right-angle prism (L22) is movably arranged along the optical axis direction; focusing is achieved by moving the first right-angle prism (L21) and / or the second right-angle prism (L22).

4. The variable power telescope according to claim 1, characterized in that: The side surfaces where the second lens (L12) of the objective lens and the third lens (L13) of the objective lens are glued together; the side surfaces where the first lens (L31) of the eyepiece and the second lens (L32) of the eyepiece are glued together; the side surfaces where the third lens (L33) of the eyepiece and the fourth lens (L34) of the eyepiece are glued together; the side surfaces where the fifth lens (L35) of the eyepiece and the sixth lens (L36) of the eyepiece are glued together; and the side surfaces where the seventh lens (L37) of the eyepiece and the eighth lens (L38) of the eyepiece are glued together.

5. The variable power telescope according to claim 1, characterized in that: When the eyepiece magnification changing group (32) moves along the optical axis, the eyepiece compensation group (31) moves in the opposite direction along the optical axis.

6. The variable power telescope according to claim 1, characterized in that: A protective glass (30) is provided on a side of the eyepiece assembly (3) close to the prism assembly (2).

7. The variable power telescope according to claim 1, characterized in that: The aperture range of the first lens (L11) of the objective lens is 70-90 mm.

8. The variable power telescope according to claim 1, characterized in that: When the magnification of the variable-power telescope changes between 60 times and 20 times, the exit pupil diameter of the variable-power telescope changes within the range of 1.5 mm to 4 mm.

9. The variable power telescope according to claim 1, characterized in that: When the magnification of the variable-power telescope varies between 60 times and 20 times, the pupil distance of the variable-power telescope is 16-20 mm.

10. The variable power telescope according to claim 1, characterized in that: The total weight of the variable-power telescope does not exceed 1500g, and the total optical length does not exceed 400mm.

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