Sighting scopes and rifle scopes

Abstract

The present invention provides an inner-focus type aiming scope and rifle scope in which the focal length of the objective lens system does not change even when the focusing lens group is moved. [Solution] An inner-focus type aiming scope 10 and rifle scope, which have an objective lens system 21 having a fixed lens group 21a fixed from the object side and a focus lens group 21b movable in the optical axis direction Od, are characterized in that the focal length of the fixed lens group 21a is set to infinity, and the incident direction of the light beam Lt incident from the fixed lens group 21a to the focus lens group 21b is parallel to the optical axis direction Od. As a result, the focal length of the objective lens system 21 can be kept constant regardless of the distance to which the focus lens group 21b is moved and focused on, and the scale size of the reticle and the amount of angle change to compensate for the effects of gravity, wind, etc. can be kept constant whether the focus is set to a long distance or a short distance.

Description

Technical Field

[0001] The present invention relates to a sight scope and a rifle scope.

Background Art

[0002] Conventionally, there have been proposed aiming telescopes and telephoto lenses that have a focus lens group movable in the optical axis direction in an objective lens system and that adjust focus, i.e., perform focusing, by moving this focus lens group. This type of aiming telescope and telephoto lens is called an inner focus type and is described, for example, in Patent Document 1 and Patent Document 2.

[0003] Patent Document 1 describes an aiming telescope in which the objective lens system has a positive first lens group and a second lens group from the object side, the second lens group consists of a convex lens group and a concave lens group, and focusing is performed by moving only one of the convex lens group and the concave lens group in the optical axis direction.

[0004] Patent Document 2 describes a telephoto lens in which the objective lens system has a positive first lens group, a negative second lens group, and a positive third lens group from the object side, and focusing is performed by moving the third lens group in the optical axis direction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the aiming telescope described in Patent Document 1, the focal length of the first lens group is not infinite when the convex lens group of the second lens group moves. When the concave lens group of the second lens group moves, the combined focal length of the first lens group and the convex lens group is not infinite. Therefore, the incident light on the convex or concave lens group is not parallel to the optical axis, so moving the convex or concave lens group changes the focal length of the objective lens system. This focal length of the objective lens system is the combined focal length of the first lens group, the convex lens group of the second lens group, and the concave lens group of the second lens group. Focal length is the distance from the center of the lens to the focal point on the optical axis.

[0007] Similarly, in the telephoto lens described in Patent Document 2, the combined focal length of the first lens group and the second lens group is not infinite. Therefore, the incident light on the third lens group is not parallel to the optical axis, and moving the third lens group changes the focal length of the objective lens system. This focal length of the objective lens system is the combined focal length of the first lens group, the second lens group, and the third lens group.

[0008] A change in the focal length of the objective lens system causes two problems. The first problem is that the scale size of the reticle differs depending on the distance to the focused target. Figure 4 is an explanatory diagram for calculating the scale size of the reticle. As shown in Figure 4, if L is the distance from the objective lens system 41 to the target point Tp, S is the amount of deviation between the target point Tp and the point of impact Pi, and α is the angle between the optical axis O of the aiming scope and the point of impact Pi, then tanα = S / L. This distance L is infinite (∞), for example, a distance of 300m or more. At this time, if h1 is the scale size of the reticle Rt on the first image plane 42, and FL is the focal length of the objective lens system 41, then tanα = h1 / FL, and the scale size of the reticle Rt is h1 = tanα × FL. In other words, the scale size h1 of the reticle Rt is determined by the focal length FL of the objective lens system 41. In other words, the scale size h1 of the reticle Rt changes when the focal length FL of the objective lens system 41 changes. This change in scale size h1 is particularly noticeable when using a single aiming scope to cover a wide range of distances from long to short. Therefore, even if you visually adjust the scale size h1 of the reticle Rt in the same way when focusing to infinity and when focusing to short distance, the result will be different.

[0009] The second problem is that the amount of angle change required to compensate for the effects of gravity, wind, etc., varies depending on the distance to the focused target. Figure 5 is an explanatory diagram for calculating the amount of angle change of the erect barrel of the aiming scope. As shown in Figure 5, the optical system 40 of the aiming scope has an objective lens system 41, a first image plane 42, a relay lens system 43, a second image plane 44, and an eyepiece lens system 45 along the optical axis O from the object side. The objective lens system 41 images the light beam Lt onto the first image plane 42, the relay lens system 43 re-images it onto the second image plane 44, and the eyepiece lens system 45 magnifies the image on the second image plane 44. Then, the light beam of the image enters the user's eye EYE. The first image plane 42, relay lens system 43, and second image plane 44 of the optical system 40 are housed in the erecting tube 46. To compensate for the effects of gravity, wind, etc., the erecting tube 46 is sometimes pressed in the direction of arrow F to tilt it, so that the image of the point of impact of target Am coincides with the center of the reticle Rt on the first image plane 42. At this time, if the amount of angular change of the first image plane 42 with respect to the optical axis O is β, the amount of movement of the first image plane 42 is h2, and the focal length of the objective lens system 41 is FL, then tanβ = h2 / FL, and the angular change amount β = arctan(h2 / FL). In other words, the angular change amount β is determined by the focal length FL of the objective lens system 41. To put it another way, when the focal length FL of the objective lens system 41 changes, the angular change amount β changes. In particular, when a single aiming scope is used to cover a range from long distance to short distance, this change in angular change amount β becomes significant. Therefore, even if the angle change β is adjusted in the same way when the focus is set to infinity and when it is set to close distance, the result will be different.

[0010] Therefore, the present invention aims to solve the above problems, and its objective is to provide an inner-focus type aiming scope and rifle scope in which the focal length of the objective lens system does not change regardless of the distance to which the focus lens group is moved to focus on the target. [Means for solving the problem]

[0011] To solve the above problems, the present invention provides an inner-focus type aiming scope comprising an objective lens system having a fixed lens group fixed from the object side and a focusing lens group movable in the optical axis direction, wherein the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis direction.

[0012] According to this invention, an inner-focus aiming scope is provided, comprising an objective lens system having a fixed lens group fixed to the object side and a focusing lens group movable in the optical axis direction, wherein the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis direction, so that the direction of incidence of the light beam incident on the focusing lens group does not change with movement of the focusing lens group and is maintained parallel to the optical axis direction, so that the focal length of the objective lens system can be kept constant even when the focusing lens group is moved. The focal length of the objective lens system is the combined focal length of the fixed lens group and the focal length of the focusing lens group.

[0013] In the present invention, the fixed lens group has a first lens group having a positive refractive power and a second lens group having a negative refractive power from the object side, and it is preferable that the combined focal length of the first lens group and the second lens group is set to infinity, and that the incident direction of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction.

[0014] According to this invention, the fixed lens group has a first lens group having a positive refractive power and a second lens group having a negative refractive power from the object side, and the focal length obtained by combining the focal length of the first lens group and the focal length of the second lens group is set to be infinite, and the incident direction of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction, so that the incident direction of the light beam incident on the focusing lens group does not change with movement of the focusing lens group and is maintained parallel to the optical axis direction, so that the focal length of the objective lens system can be kept constant even when the focusing lens group is moved. The focal length of the objective lens system is the focal length obtained by combining the focal length of the first lens group, the focal length of the second lens group and the focal length of the focusing lens group.

[0015] In the present invention, it is preferable that the device further has a first image plane, the focusing lens group has a positive refractive power, and the light beam emitted from the focusing lens group is imaged onto the first image plane. According to this invention, the device further has a first image plane, the focusing lens group has a positive refractive power, and the light beam emitted from the focusing lens group can be imaged onto the first image plane.

[0016] The present invention relates to an inner-focusing rifle scope comprising an objective lens system having a fixed lens group fixed to the object side and a focusing lens group movable in the optical axis direction, wherein the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis direction.

[0017] According to this invention, an inner-focus rifle scope is provided, comprising an objective lens system having a fixed lens group fixed to the object side and a focusing lens group movable in the optical axis direction, wherein the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis direction, so that the direction of incidence of the light beam incident on the focusing lens group does not change with movement of the focusing lens group and is maintained parallel to the optical axis direction, so that the focal length of the objective lens system can be kept constant even when the focusing lens group is moved. The focal length of the objective lens system is the combined focal length of the fixed lens group and the focal length of the focusing lens group.

[0018] In the present invention, the fixed lens group has a first lens group having a positive refractive power and a second lens group having a negative refractive power from the object side, and it is preferable that the combined focal length of the first lens group and the second lens group is set to infinity, and that the incident direction of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction.

[0019] According to this invention, the fixed lens group has a first lens group having a positive refractive power and a second lens group having a negative refractive power from the object side, and the focal length obtained by combining the focal length of the first lens group and the focal length of the second lens group is set to be infinite, and the incident direction of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction, so that the incident direction of the light beam incident on the focusing lens group does not change with movement of the focusing lens group and is maintained parallel to the optical axis direction, so that the focal length of the objective lens system can be kept constant even when the focusing lens group is moved. The focal length of the objective lens system is the focal length obtained by combining the focal length of the first lens group, the focal length of the second lens group and the focal length of the focusing lens group.

[0020] In the present invention, it further has a first image plane, the focus lens group has a positive refractive power, and it is preferable that the light beam emitted from the focus lens group forms an image on the first image plane. According to this invention, it further has a first image plane, the focus lens group has a positive refractive power, and the light beam emitted from the focus lens group can form an image on the first image plane.

Effects of the Invention

[0021] As described above, according to the present invention, the fixed lens group of the objective lens system has an infinite focal length set, and the incident direction of the light beam incident from the fixed lens group to the focus lens group is parallel to the optical axis direction. Therefore, an excellent effect can be achieved in that the focal length of the objective lens system can be kept constant even when the focus lens group is moved to focus on targets at any distance.

Brief Description of the Drawings

[0022] [Figure 1] It is a perspective view showing a telescopic sight according to an embodiment of the present invention. [Figure 2] It is a schematic diagram showing the optical system of the telescopic sight of this embodiment. [Figure 3] It is a schematic diagram showing the optical system of the telescopic sight of the comparative example. [Figure 4] It is an explanatory diagram for calculating the dimension of the scale of the reticle. [Figure 5] It is an explanatory diagram for calculating the amount of change in the angle of the erecting cylinder.

Modes for Carrying Out the Invention

[0023] The following describes in detail an aiming scope according to an embodiment of the present invention. Figure 1 is a perspective view showing an aiming scope according to an embodiment of the present invention. As shown in Figure 1, the aiming scope 10 is, for example, a rifle scope and has a scope body 11, an objective lens section 12, and an eyepiece lens section 13. The scope body 11 is cylindrical and extends in one direction. The objective lens section 12 and the eyepiece lens section 13 are cylindrical and are attached to one end and the other end of the scope body 11, respectively. The optical axis O passes sequentially through the interiors of the objective lens section 12, the scope body 11, and the eyepiece lens section 13.

[0024] The middle section of the scope body 11 is equipped with a first adjustment section 14, a second adjustment section 15, and a focus adjustment section 16. These three sections are cylindrical bodies equipped with dials, arranged at angular intervals around the optical axis O, and each protrudes outward from the scope body 11. The first adjustment section 14 is an elevation dial, used to compensate for the effect of gravity on the bullet. The second adjustment section 15 is a windage dial, used to compensate for the effect of wind on the bullet. The focus adjustment section 16 is used to adjust the focus. A zoom ring section 17 is also provided on the eyepiece lens section 13 side of the scope body 11. This zoom ring section 17 is an annular shape equipped with a dial, and is rotatably mounted on the outer circumference of the scope body 11 around the optical axis O. This zoom ring section 17 is used to enlarge or reduce the target image.

[0025] Figure 2 is a schematic diagram showing the optical system of the aiming scope of this embodiment. As shown in Figure 2, the optical system 20 of the aiming scope 10 is housed inside the aiming scope 10 and has an objective lens system 21, a first image plane 22, a relay lens system 23, a second image plane 24, and an eyepiece lens system 25 along the optical axis O from the object side. The objective lens system 21 is housed in the objective lens section 12, and the eyepiece lens system 25 is housed in the eyepiece section 13, with the first image plane 22 and the relay lens system 23 The second image plane 24 is housed inside the scope body 11.

[0026] The objective lens system 21 has a fixed lens group 21a and a focusing lens group 21b, starting from the object side. The fixed lens group 21a is fixed and configured to be immovable in the optical axis direction Od. The fixed lens group 21a is set to have an infinite focal length. Therefore, the incident direction of the light beam Lt incident from the fixed lens group 21a to the focusing lens group 21b is parallel to the optical axis direction Od. This optical axis direction Od is the direction along the optical axis O of the optical system 20, that is, the direction along the optical axis O of the aiming scope 10.

[0027] Specifically, this fixed lens group 21a has a first lens group 21aa and a second lens group 21ab, from the object side. The first lens group 21aa has a positive refractive power, and the second lens group 21ab has a negative refractive power. The first lens group 21aa and the second lens group 21ab are fixed and configured to be immovable in the optical axis direction Od. The first lens group 21aa and the second lens group 21ab are arranged at a predetermined distance apart in the optical axis direction Od. The first lens group 21aa and the second lens group 21ab are set so that the combined focal length of the first lens group 21aa and the second lens group 21ab is infinite. Therefore, the incident direction of the light beam Lt that passes through the first lens group 21aa and enters the focus lens group 21b from the second lens group 21ab is parallel to the optical axis direction Od.

[0028] The focusing lens group 21b has positive refractive power and images the light beam Lt emitted from the focusing lens group 21b onto the first image plane 22. This focusing lens group 21b is configured to be movable along the optical axis direction Od. By rotating the focus adjustment unit 16 of the aiming scope 10, the focusing lens group 21b reciprocates between the object side and the eyepiece side along the optical axis direction Od. Moving the focusing lens group 21b towards the objective side along the optical axis direction Od allows the focus to be set to a close distance, and moving the focusing lens group 21b towards the eyepiece side along the optical axis direction Od allows the focus to be set to a long distance (infinity). In Figure 2, the solid line shows the focusing lens group 21b in the position where the focus is set to infinity, and the dotted line shows the focusing lens group 21b' in the position where the focus is set to a close distance.

[0029] The first image plane 22 and the second image plane 24 each have reticles Rt and Rt', respectively. These reticles Rt and Rt' are, for example, glass-etched reticles and are equipped with markings for indexing. These markings are crosses or T-shapes with scales. An image is formed on the first image plane 22 by the objective lens system 21.

[0030] The relay lens system 23 is for re-imaging the image from the first image plane 22 onto the second image plane 24. This relay lens system 23 includes a condenser lens 23a and an erector lens group 23b. The eyepiece system 25 is for magnifying the image on the second image plane 24. The image on the second image plane 24 is magnified or reduced by the rotation of the zoom ring portion 17 of the aiming scope 10.

[0031] In the objective lens system 21, the incident direction of the light beam Lt that enters the focusing lens group 21b from the second lens group 21ab through the first lens group 21aa is parallel to the optical axis direction Od. Therefore, even if the focusing lens group 21b is moved to either the objective side or the eyepiece side along the optical axis direction Od, the incident direction and incident angle of the light beam Lt entering the focusing lens group 21b do not change and are maintained parallel to the optical axis direction Od. As a result, the focal length of the objective lens system 21 does not change and is kept constant regardless of whether the focusing lens group 21b is moved to either the objective side or the eyepiece side along the optical axis direction Od.

[0032] As described above, in the aiming scope 10, light (light beam Lt) passes sequentially through the first lens group 21aa, the second lens group 21ab, the focusing lens group 21b, the first image plane 22, the relay lens system 23, the second image plane 24, and the eyepiece lens system 25 of the objective lens system 21 before entering the user's eye.

[0033] In this embodiment, the first lens group 21aa and the second lens group 21ab of the fixed lens group 21a have a combined focal length of infinitely long, and the incident direction of the light beam Lt incident from the fixed lens group 21a, i.e., the second lens group 21ab, to the focus lens group 21b is parallel to the optical axis direction Od. Furthermore, the focus lens group 21b is configured to reciprocate between the objective side and the eyepiece side of the optical axis direction Od. Therefore, no matter whether the focus lens group 21b moves to the objective side or the eyepiece side of the optical axis direction Od, the incident direction and incident angle of the light beam Lt incident on the focus lens group 21b do not change and are maintained parallel to the optical axis direction Od. Thus, the focal length of the objective lens system can be kept constant regardless of the distance to which the focus lens group 21b is moved to focus on a target. The focal length of this objective lens system is the sum of the focal lengths of the first lens group 21aa, the second lens group 21ab, and the focusing lens group 21b. This allows the reticle scale dimensions and the amount of angular change to compensate for the effects of gravity, wind, etc., to remain constant regardless of the distance to which the focusing lens group 21b is moved and the target is focused.

[0034] It should be noted that the aiming scope 10 of this embodiment is not limited to the illustrated example described above, and various modifications can be made without departing from the spirit of the present invention. For example, in this embodiment, the aiming scope 10 is a rifle scope, but it is not limited to this, and may also be a telescope or binoculars.

[0035] Furthermore, in this embodiment, the fixed lens group 21a of the objective lens system 21 is composed of two lens groups, the first lens group 21aa and the second lens group 21ab, but it may be composed of one lens group or three or more lens groups.

[0036] In this embodiment, both the first image plane 22 and the second image plane 24 have reticles Rt and Rt', but it is also possible to have a reticle on only one of the first image plane 22 or the second image plane 24. That is, it is possible to have a reticle Rt only on the first image plane 22 and not on the second image plane 24, or conversely, to have no reticle Rt on the first image plane 22 and only on the second image plane 24 a reticle Rt'.

[0037] (Examples) The focal length of the objective lens system 21 according to this embodiment was calculated using commercially available software. The d-line (wavelength λ = 587.6 nm) was used in this calculation. Table 1 shows the overall specifications of the objective lens system 21. Table 2 shows the lens data of the objective lens system 21. Table 3 shows the variable interval data. That is, Tables 1 and 2 are the prerequisite information for the calculation, and Table 3 is the calculated result of the focal length.

[0038] [Table 1]

[0039] As shown in Figure 2 and Table 1, L1 is the distance (mm) from the surface (outer surface) of the first lens group 21aa of the objective lens system 21 to the first image plane 22. f1 is the focal length (mm) of the first lens group 21aa. f2 is the focal length (mm) of the second lens group 21ab. f3 is the focal length (mm) of the focusing lens group 21b. The combined F is the focal length of the fixed lens group 21a, which is set to infinity (∞). This fixed lens group 21a is the combined focal length of the first lens group 21aa's focal length f1 and the second lens group 21ab's focal length f2. The focal lengths of the relay lens system 23 and the eyepiece lens system 25 are omitted.

[0040] [Table 2]

[0041] In Table 2, the surface number indicates the order of the lens surfaces arranged sequentially from the object side. R indicates the radius of curvature (mm) of the lens surface corresponding to the surface number. In this radius of curvature R, a lens surface convex towards the object side is given a positive value, and a lens surface concave towards the object side is given a negative value. d indicates the lens thickness (mm) or air gap distance (mm) on the optical axis at the lens surface corresponding to the surface number. nd indicates the refractive index of the optical material corresponding to the surface number with respect to the d line (wavelength λ = 587.6 nm). vd indicates the Abbe number based on the d line of the optical material corresponding to the surface number. Outer diameter indicates the outer diameter (mm) of the lens corresponding to the surface number. Note that "0.000" for the radius of curvature R indicates a plane or aperture. The refractive index of air, nd = 1.00000, is omitted.

[0042] [Table 3]

[0043] In Table 3, the focal distance is the distance at which the image is in focus, ranging from infinity (∞) to 10m. Specifically, the focal distances are infinity (∞), 1000m, 500m, 300m, 100m, 50m, and 10m. d5 and d7 are variable distances (mm) between lens surfaces corresponding to the focal distances. Specifically, d5 is the variable distance corresponding to surface number 5 in Table 2, and in Figure 2, it is the distance between the second lens group 21ab and the focusing lens group 21b in the optical axis direction Od. d7 is the variable distance corresponding to surface number 7 in Table 2, and in Figure 2, it is the distance between the focusing lens group 21b and the first image plane 22 in the optical axis direction Od. The combined focal length is the focal length (mm) of the objective lens system 21 corresponding to the focal distance. The focal length of this objective lens system 21 is the combined focal length of the first lens group 21aa (f1), the second lens group 21ab (f2), and the focusing lens group 21b (f3). As can be seen from Table 3, the combined focal length is 188.00 mm for all focal distances from infinity (∞) to the near distance of 10 m. Therefore, in this embodiment, the combined focal length does not change with the focal distance and is maintained at 188.00 mm. In other words, in this embodiment, the focal length of the objective lens system 21 does not change and is kept constant regardless of the focal distance, from the far distance of infinity (∞) to the near distance of 10 m.

[0044] (Comparative example) Figure 3 is a schematic diagram showing the optical system of the comparative example aiming scope. As shown in Figure 3, the optical system 30 of this comparative example is a conventional inner-focus type optical system. In the optical system 20 of this embodiment shown in Figure 2, the fixed lens group 21a is composed of two lens groups, the first lens group 21aa and the second lens group 21ab, and the focal length of the fixed lens group 21a is set to infinity. In contrast, the optical system 30 of the comparative example is composed of a single lens group 31a, and the focal length of the fixed lens group 31a is not set to infinity.

[0045] This optical system 30 is housed inside the aiming scope 10, similar to the optical system 20 of this embodiment. The fixed lens group 31a of the objective lens system 31 is fixed, and the focus lens group 31b is configured to be movable in the optical axis direction Od. In Figure 3, the focus lens group 31b shown by the solid line indicates the position where the focus is set to infinity, and the focus lens group 31b' shown by the dotted line indicates the position where the focus is set to 10m. The first image plane 32, relay lens system 33, second image plane 34, and eyepiece system 35 in the optical system 30 are the same as the first image plane 22, relay lens system 23, second image plane 24, and eyepiece system 25 of the optical system 20 of this embodiment, respectively, and their description is omitted. The first image plane 32 and second image plane 34 of the optical system 30 are equipped with reticles Rt and Rt', respectively, similar to the first image plane 22 and second image plane 24 of the optical system 20. The relay lens system 33 of the optical system 30 has a condenser lens 33a and an erector lens group 33b, similar to the relay lens system 23 of the optical system 20.

[0046] The focal length of the comparative objective lens system 31 was calculated using commercially available software. The d-line (wavelength λ = 587.6 nm) was used in this calculation. Table 4 shows the overall specifications of the objective lens system 31. Table 5 shows the lens data for the objective lens system 31. Table 6 shows the variable interval data. In other words, Tables 4 and 5 are the prerequisite information for the calculation, and Table 6 shows the calculated focal length.

[0047] [Table 4]

[0048] As shown in Figure 3 and Table 4, L1' is the distance (mm) from the surface (outer surface) of the fixed lens group 31a of the objective lens system 31 to the first image plane 32. f1' is the focal length (mm) of the fixed lens group 31a. f3' is the focal length (mm) of the focusing lens group 31b. As in the above embodiment, the focal lengths of the relay lens system 33 and the eyepiece lens system 35 are omitted.

[0049] [Table 5]

[0050] In Table 5, the surface number indicates the order of the lens surfaces arranged sequentially from the object side. R indicates the radius of curvature (mm) of the lens surface corresponding to the surface number. In this radius of curvature R, a lens surface convex towards the object side is given a positive value, and a lens surface concave towards the object side is given a negative value. d indicates the lens thickness (mm) or air gap distance (mm) on the optical axis at the lens surface corresponding to the surface number. nd indicates the refractive index of the optical material corresponding to the surface number with respect to the d line (wavelength λ = 587.6 nm). vd indicates the Abbe number based on the d line of the optical material corresponding to the surface number. Outer diameter indicates the outer diameter (mm) of the lens corresponding to the surface number. Note that "0.000" for the radius of curvature R indicates a plane or aperture. The refractive index of air, nd = 1.00000, is omitted.

[0051] [Table 6]

[0052] In Table 6, the focal distance is the distance at which the image is in focus, ranging from infinity (∞) for long distances to 10m for short distances. These focal distances are infinity (∞), 1000m, 500m, 300m, 100m, 50m, and 10m, as in the above embodiment. d3′ and d5′ are variable distances (mm) between lens surfaces corresponding to the focal distance. Specifically, d3′ is the variable distance corresponding to surface number 3 in Table 5, and in Figure 3, it is the distance between the fixed lens group 31a and the focusing lens group 31b in the optical axis direction Od. d5′ is the variable distance corresponding to surface number 5 in Table 5, and in Figure 3, it is the distance between the focusing lens group 31b and the first image plane 32 in the optical axis direction Od. The combined focal length is the focal length (mm) of the objective lens system 31 corresponding to the focal distance. The focal length of this objective lens system 31 is the combined focal length of the fixed lens group 31a (f1') and the focusing lens group 31b (f3'). As can be seen from Table 6, the combined focal length changes depending on the focal distance. The difference in combined focal length is small from infinity (∞) to 100m, but the difference in combined focal length is large between the far distance (infinity (∞)) and the near distances (50m and 10m). Specifically, the difference in combined focal length between infinity (∞) and 100m is 1.00mm, the difference between infinity (∞) and 50m is 1.95mm, and the difference between infinity (∞) and 10m is 8.17mm. As a result, the difference in focal length of the objective lens system 31 is small when the focal distance is from infinity (∞) to 100m, but the difference in focal length of the objective lens system 31 is large when the focal distance is from the far distance (infinity (∞)) to the near distance of 10m). In other words, when a single aiming scope is used to cover the focal distance from far distance (infinity) to near distance, the difference in focal length of the objective lens system 31 becomes significant. [Explanation of Symbols]

[0053] 10…Aiming scope, 11…Scope body, 12…Objective lens section, 13…Eyepiece section, 14…First adjustment section, 15…Second adjustment section, 16…Focus adjustment section, 17…Zoom ring section, 20, 30, 40…Optical system, 21, 41…Objective lens system, 21a, 31a…Fixed lens group, 21aa…First lens group, 21ab…Second lens group, 21b, 21b′, 31b, 31b′…Focus lens group, 22, 32, 42…First image plane, 23, 33, 43…Relay lens system, 23a, 33a…Condenser lens, 23b, 33b…Erector lens group ,24,34,44…Second image plane, 25,35,45…Eyepiece system, 46…Erecting tube, Am…Target, d…Lens thickness or distance between air gaps, d5,d7,d3′,d5′…Variable distance, EYE…Eye, F…Arrow, FL,f1,f1′,f2,f3,f3′,Combined F…Focal length, h1…Scale dimension, h2…Amount of movement, L,L1,L1′…Distance, Lt…Light beam, nd…Refractive index, O…Optical axis, Od…Axis direction of optical axis, Pi…Point of impact, R…Radius of curvature, Rt,Rt′…Reticle, S…Amount of displacement, Tp…Target point, vd…Abbe number, α…Angle, β…Angle change, λ…Wavelength.

Claims

1. An inner-focus type aiming scope comprising an objective lens system having a fixed lens group fixed to the object side and a focus lens group movable in the optical axis direction, A aiming scope in which the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis.

2. The aforementioned fixed lens group has a first lens group having a positive refractive power from the object side and a second lens group having a negative refractive power. The aiming scope according to claim 1, wherein the combined focal length of the first lens group and the second lens group is set to be infinite, and the direction of incidence of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction.

3. The aiming scope according to claim 1 or 2, further comprising a first image plane, wherein the focusing lens group has positive refractive power, and the light beam emitted from the focusing lens group is imaged onto the first image plane.

4. An inner-focusing rifle scope comprising an objective lens system having a fixed lens group fixed to the object side and a focusing lens group movable in the optical axis direction, A rifle scope in which the fixed lens group is set to have an infinite focal length, and the direction of incidence of the light beam incident from the fixed lens group to the focusing lens group is parallel to the optical axis.

5. The aforementioned fixed lens group has a first lens group having a positive refractive power from the object side and a second lens group having a negative refractive power. The rifle scope according to claim 4, wherein the combined focal length of the first lens group and the second lens group is set to be infinite, and the incident direction of the light beam incident from the second lens group to the focusing lens group is parallel to the optical axis direction.

6. The Lylescope according to claim 4 or 5, further comprising a first image plane, wherein the focusing lens group has positive refractive power, and the light beam emitted from the focusing lens group is imaged onto the first image plane.

Images