Optical device and optometry equipment comprising such an optical device

Abstract

An optical device (2) comprises a lens (52) and a control member (62), the control member being configured such that movement of the control member (62) produces a change in the optical power provided along the optical axis of the lens (52). The optical device (2) further comprises a frame (8), a motor (54) and a drive member (60). The motor (54) comprises an output shaft (58) rotatably coupled to the drive member (60). The motor (54) and the control member (62) are mounted in the frame (8) such that the drive member (60) and the control member (62) mechanically cooperate. The drive member (60) is rotatably mounted in the frame (8). The optical device (2) comprises a biasing device (83) for maintaining the drive member (60) in a predetermined axial position along the axis of the output shaft and relative to the frame (8). The optical device can be used in an optometry device.

Description

Technical Field

[0001] The present invention relates to optical devices and, in particular, to optical devices adapted to provide variable optical power for correcting refractive errors.

[0002] More precisely, the invention relates to an optical device comprising a lens and a control member configured such that movement of the control member produces a change in the optical power provided along the optical axis of the lens. The invention also relates to an optometry apparatus comprising such an optical device. Background Art

[0003] Document WO 2015 / 107303 describes the optical device just mentioned.

[0004] The optical device further comprises a frame, a motor comprising an output shaft, the drive member being fixed on the output shaft, and a control member (eg a gear) being mounted in the frame such that the drive member and the control member mechanically cooperate.

[0005] Thus, by appropriate control of the motor, the drive member may be activated and the control member may be moved (eg, rotated gears) to a position where the lens provides a particular optical power.

[0006] However, the motors used in this case (usually electric motors) are usually designed with axial play at the output shaft to ensure normal operation over a wide temperature range.

[0007] However, this axial play causes inaccuracies in the positioning of the drive member relative to the frame and thus in the control of the movement of the control member from the motor.

[0008] This is particularly problematic when no information about the actual position of the control member is available, for example when the motion control is based on an encoder which determines the angular position of the output shaft. Summary of the invention

[0009] In this case, the present invention provides an optical device, the optical device includes a lens and a control member, the control member is configured so that movement of the control member produces a change in the optical focal length provided along the optical axis of the lens, the optical device further includes a frame, a motor and a drive member, the motor includes an output shaft rotatably connected to the drive member, the motor and the control member are mounted in the frame so that the drive member and the control member mechanically cooperate, characterized in that the drive member is rotatably mounted in the frame, and the optical device includes a biasing device for maintaining the drive member in a predetermined axial position along the axis of the output shaft and relative to the frame.

[0010] The drive member is thus precisely positioned and the movement of the control member can therefore be accurately controlled, which results in precise control of the optical power provided by the optical device.

[0011] The optical device may also include one or more of the following features:

[0012] - the drive member is mounted in the frame via at least one rolling bearing;

[0013] - the biasing means are arranged to axially push the assembly of the drive member and the rolling bearing against the wall of the frame;

[0014] - the drive member is press-fitted into the inner ring of the at least one rolling bearing;

[0015] - the biasing means are arranged to axially push the outer ring of said at least one rolling bearing against said wall;

[0016] - the drive member is mounted in the frame via the at least one rolling bearing and the further rolling bearing;

[0017] - biasing means are interposed between the further rolling bearing and the frame so that said at least one rolling bearing is urged against said wall of the frame;

[0018] - the at least one rolling bearing and the further rolling bearing are respectively mounted on two axial portions of the drive member separated by a threaded axial portion of the drive member;

[0019] - the at least one rolling bearing and the further rolling bearing are mounted on the first axial portion of the drive member;

[0020] - The drive element is also mounted to the frame via another rolling bearing;

[0021] - said further rolling bearing is mounted on the second axial portion of the drive member;

[0022] - the first axial portion and the second axial portion are separated by a threaded axial portion of the drive member;

[0023] - the biasing means comprises a helical spring;

[0024] - the biasing means comprises a spring washer;

[0025] - the biasing means is adapted to apply a biasing force along the axis of the output shaft which is greater than the force applied by the drive member on the control member to drive the control member to move;

[0026] - the optical device further comprises an encoder associated with the motor for determining the angular position of the output shaft;

[0027] - the drive member is a worm;

[0028] - the control member is a gear;

[0029] - The worm meshes with the gear;

[0030] - the lens is a cylindrical lens that can rotate with the control member;

[0031] - The invention may also provide a lens adapted to provide a variable spherical power adjustable by rotation of a control member.

[0032] The present invention also provides an optometry device (eg, an optometer) comprising an optical apparatus. DETAILED DESCRIPTION

[0033] Illustrative embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which:

[0034] - Figure 1 is a functional diagram of an optical device according to a possible embodiment of the present invention;

[0035] - Figure 2 yes Figure 1 A partial view of a first transmission system of an optical device;

[0036] - Figure 3 is a side view of a first transmission system;

[0037] - Figure 4 yes Figure 1 A partial view of a second transmission system of the optical device; and

[0038] - Figure 5 is a side view of the second transmission system.

[0039] Figure 1 Elements of an optical device 2 constructed in accordance with the teachings of the present invention are shown.

[0040] This optical device 2 includes at least one lens 12; 52; 92, at least one motor 14; 54; 94 and at least one transmission system 16; 56; 96, which is configured to move at least a portion of the lens 12; 52; 92, thereby changing the optical focal length provided along the optical axis X of the lens 12; 52; 92 when the motor 14; 54; 94 is operated.

[0041] In this example, the optical device 2 comprises:

[0042] a first motor 14, a lens 12 with a variable spherical power (along the optical axis X of the lens 12), and a first transmission system 16, the first transmission system being configured to rotate the ring of the lens 12 and to change the spherical power (along the optical axis X of the lens 12) when the first motor 14 is operated;

[0043] - a second motor 54, a first cylindrical lens 52 (i.e., a lens having cylindrical power along the optical axis X of the lens 52), and a second transmission system 56, the second transmission system being configured to rotate the first cylindrical lens 52 to change the optical power (here, the cylindrical correction axis) when the second motor 54 is operated;

[0044] -A third motor 94, a second cylindrical lens 92 (i.e., a lens having cylindrical power along the optical axis X of the lens 52), and a third transmission system 96, wherein the third transmission system is configured to rotate the second cylindrical lens 92 to change the optical power (here, the cylindrical correction axis) when the second motor 54 is operated.

[0045] These elements are mounted in the frame 8 of the optical device 2 so that the lens 12 with variable spherical power, the first cylindrical lens 52 and the second cylindrical lens 92 have the same optical axis X (eg Figure 1 For further details in this regard, reference may be made to document WO 2015 / 107303.

[0046] like Figure 1 As shown, the optical device 2 also includes a control circuit 6, which is designed to control the movement of the motors (here the first motor 14, the second motor 54 and the third motor 94) so ​​that the lens or the combination of lenses 12, 52, 92 provides the sought optical focal length, as described in document WO 2015 / 107303.

[0047] The optical device 2 may thus be used to provide a predefined optical correction to an eye of a person when the eye is positioned along the optical axis X. The optical device 2 may thus be comprised in an optical apparatus, such as an optometre, for use, for example, when performing a subjective refraction test on a patient.

[0048] In this embodiment, each motor 14; 54; 94 includes an encoder, which is used to determine the angular position of the output shaft 18; 58 of the relevant motor 14; 54; 94, and to send information representing this angular position to the control circuit 6 (based on this information, the control circuit 6 can accurately control the position of the relevant output shaft 18; 58).

[0049] Now refer to Figures 2 to 5 The first transmission system 16 and the second transmission system 56 are described. The third transmission system 96 is constructed in the same manner as the second transmission system 56 and therefore will not be described further.

[0050] Each transmission system 16;56 comprises a drive member 20;60 rotatably coupled to the output shaft 18;58 of the corresponding motor 14;54 and a control member 22;62 designed to produce, when moved, a variation in the optical power provided along the optical axis X of the associated lens 12;52.

[0051] The drive member 20; 60 is mounted relative to the output shaft 18; 58 of the corresponding motor 14; 54 so as to be connected or fixed to the output shaft 18; 58 so that the drive member 20; 60 and the output shaft 18; 58 are coupled when rotating about the axis of the output shaft (i.e., when the corresponding motor 14; 54 is operating). However, the drive member 20; 60 can actually be mounted relative to the output shaft 18; 58 so as to translate relative to the output shaft 18; 58 along the axis of the output shaft 18; 58.

[0052] In the present embodiment, the drive member 20; 60 is a worm. This worm 20; 60 is here fixed to the output shaft 18; 58, the axis of the worm 20; 60 extending along the axis of the output shaft 18; 58, so that the rotation of the output shaft 18; 58 (when the motor 14; 54 is operated) causes the worm 20; 60 to rotate (about the axis of the worm 20; 60).

[0053] In the present embodiment, the control member 22; 62 is a gear. This gear 22; 62 meshes with the worm 20; 60 so that a rotation of the worm 20; 60 (about the axis of the worm 20; 60) produces a rotation of the gear 22; 62 about the axis of the gear 22; 62 (the axis of the gear 22; 62 being perpendicular to the axis of the worm 20; 60, i.e. perpendicular to the axis of the output shaft 18; 58 of the motor 14; 54, and / or being located at a distance from the axis of the worm 20; 60).

[0054] Figure 2 and Figure 3 Details of the first transmission system 16 are shown.

[0055] like Figure 2 As can be seen in the figure, in this embodiment, the framework 8 includes a frame 9 and a sleeve 24. The frame 9 is made of, for example, a plastic material, such as polyetheretherketone (PEEK). The sleeve 24 is made of, for example, a metal, such as stainless steel.

[0056] The sleeve 24 is, for example, received in a complementary recess 26 formed in the frame 9 and is retained in this complementary recess 26 thanks to a ring 28 fixed to the frame 9 by screws 30 .

[0057] The sleeve 24 defines a through hole 32 through which the output shaft 18 of the motor 14 and the drive member 20 extend. The through hole 32 comprises a first cylindrical portion 34 for partially accommodating the motor 14 and a second cylindrical portion 36 for accommodating at least rolling bearings, here two rolling bearings 38, 40.

[0058] The sleeve 24 forms an annular wall 42 at the axial end of the second cylindrical portion 36 for abutment by the bearing 38 , as further described below.

[0059] The frame 9 defines a cavity 44 communicating with the recess 26. In the present embodiment, the cavity 44 includes (along the axis of the cavity 44, sequentially from a portion located near the recess 26 to a portion away from the recess 26):

[0060] - a first cylindrical portion 45 having a first diameter;

[0061] - a second cylindrical portion 46 having a second diameter smaller than the first diameter; and, here

[0062] - a third cylindrical portion 47 having a third diameter smaller than the second diameter.

[0063] In the present example, the first cylindrical portion 45 accommodates the spring washer 43. The frame 9 has an annular wall 49 (connecting the first cylindrical portion 45 and the second cylindrical portion 46, ie formed by the diameter difference between the first cylindrical portion 45 and the second cylindrical portion 46).

[0064] The spring washer 43 is thus retained (axially) between the wall 49 and the outer ring of the rolling bearing 40 and presses the rolling bearing assembly 38 , 40 against a wall 42 formed in the frame 8 , here in the sleeve 24 .

[0065] Another rolling bearing 48 is housed in the cavity at the level of the third cylindrical portion 47. The rolling bearing 48 is able to translate axially under the force of the spring washer 43 and is tightly mounted on the drive member 20.

[0066] The drive member 20 comprises a first axial portion 23 , a second axial portion 25 , and a threaded portion 21 separating the first and second axial portions 23 , 25 (ie here extending between them along the axis of the drive member 20 ).

[0067] The diameter of the second cylindrical portion 46 (the second diameter as described above) is larger than the outer diameter of the threaded portion 21 of the drive member 20 (such that the cavity 44 accommodates the drive member 20 ).

[0068] The rolling bearings 38, 40 are mounted on the first axial portion 23 of the drive member 20. Precisely here, the first axial portion 23 of the drive member 20 is press-fitted into the respective inner rings of the rolling bearings 38, 40.

[0069] A further rolling bearing 48 is mounted on the second axial portion 25 of the drive member 20 . To be precise here, the second axial portion 25 of the drive member 20 is press-fitted into the inner ring of the further rolling bearing 48 .

[0070] The drive member 20 is thus rotatably mounted in the frame 8 (about an axis of the drive member 20 , here corresponding to the axis of the output shaft).

[0071] Due to the construction just described, when the rolling bearing assemblies 38, 40 are pushed against the wall 42 of the frame 8 due to the spring washers 43 and the drive member 20 is pressed into the inner rings of the rolling bearings 38, 40, the drive member 20 is maintained in a predetermined axial position relative to the frame 8 along the axis of the output shaft 18 (here the same as the axis of the drive member 20).

[0072] The spring washer 43 can, for example, be selected to apply a biasing force along the axis of the output shaft 18 that is greater than the force applied by the drive member 20 on the control member 22 to drive the control member 22 to move (for example, three times or greater, here four times or greater, of the force applied by the drive member 20).

[0073] The spring rate is designed / selected so that thermal expansion does not significantly affect the biasing force applied by the spring washer 43 along the axis of the output shaft 18 .

[0074] For example, the force applied by the drive member 20 to the control member 22 to drive the control member 22 to move is between 0.05N and 0.2N, here 0.1N; the biasing force applied by the spring washer 43 along the axis of the output shaft 18 is between 0.2N and 1N, here 0.4N.

[0075] The movement (here rotation) of the control member 22 can thus be precisely controlled by a corresponding movement of the drive member 20 (which is itself driven by the motor 14). The control of the optical power (here spherical power) provided by the lens 12 along the lens axis X is thus improved.

[0076] In the present case, the rotation of the control member 22 is converted into a translational movement by means of a screw device (not shown), which produces a deformation of a deformable membrane (not shown) of the lens 12 , thereby varying the spherical power of the lens 12 .

[0077] Figure 4 and Figure 5 Details of the second transmission system 56 are shown.

[0078] like Figure 4 As shown, the frame 8 here also comprises (in addition to the already mentioned frame) a bushing 64. The bushing 64 is made of metal, for example stainless steel.

[0079] The frame 9 defines a cavity 84, which includes (along the axis of the cavity 84, in order from a portion located near the motor 54 to a portion away from the motor 54):

[0080] - a first cylindrical portion 85 having a fourth diameter;

[0081] - a second cylindrical portion 86 having a fifth diameter smaller than the third diameter; and, here

[0082] - a third cylindrical portion 87 having a sixth diameter smaller than the second diameter.

[0083] The bushing 64 is received here in the cavity 84 at the level of the first cylindrical portion 85. A portion of the bushing 64 has a cylindrical shape, the diameter of which corresponds to the fourth diameter mentioned above. The bushing 64 is fixed to the frame 9, for example, by means of a clip 68 cooperating with a groove 70 formed on the bushing 64.

[0084] The bushing 64 defines a through-bore 72 through which the output shaft 58 of the motor 54 and the end of the drive member 60 extend.

[0085] The bushing 64 defines a first recess 74 that partially receives the motor 54 and a second recess 76 (located axially opposite the first recess 74 ) that accommodates the rolling bearing 78 .

[0086] The second recess 76 defines an annular wall 82 against which the rolling bearing 78 abuts, as will be explained further below.

[0087] The drive member 60 comprises a first axial portion 63 , a second axial portion 65 , and a threaded portion 61 separating the first and second axial portions 63 , 65 (ie here extending between them along the axis of the drive member 60 ).

[0088] The diameter of the second cylindrical portion 86 (the fifth diameter described above) is greater than the outer diameter of the threaded portion 61 of the drive member 60 (for the cavity 84 to accommodate the drive member 60).

[0089] The rolling bearing 78 is mounted on the first axial portion 63 of the drive member 60 . To be precise here, the end of the first axial portion 63 of the drive member 60 is press-fitted into a corresponding inner ring of the rolling bearing 78 .

[0090] A further rolling bearing 80 is mounted on the second axial portion 65 of the drive member 60 . To be precise here, the second axial portion 65 of the drive member 60 is press-fitted into the inner ring of the further rolling bearing 80 .

[0091] like Figure 4 and Figure 5 As can be seen in the figure, this rolling bearing 80 is accommodated in a cavity 84, here in a third cylindrical portion 87 of the cavity 84. The outer diameter of the rolling bearing 80 here corresponds to (is actually equal to) the diameter (sixth diameter) of the third cylindrical portion, so that the rolling bearing 80 can move in the third cylindrical portion 87 (by translating along the axis of the drive member 60, i.e., here the axis of the output shaft 58).

[0092] The drive member 60 is thus rotatably mounted in the frame 8 (about an axis of the drive member 60 , here corresponding to the axis of the output shaft).

[0093] The coil spring 83 is interposed between the end wall 81 of the cavity 84 (ie, here, the end wall of the third cylindrical portion) and the rolling bearing 80 (here, precisely, the outer ring of the rolling bearing 80).

[0094] In the present embodiment, a ring 89 is further interposed between the coil spring 83 and the rolling bearing 80. The circular edge of the ring 89 (the circular edge pointing toward the rolling bearing 80) contacts only the outer ring of the rolling bearing 80, which ensures that the force generated by the compressed coil spring 83 is applied only to the outer ring of the rolling bearing 80, and not to the inner ring of the rolling bearing 80 (which would hinder the rotation of the control member 60).

[0095] When the coil spring 83 is compressed between the end wall 81 and the rolling bearing 80 , the coil spring 83 pushes the assembly comprising the drive member 60 and the rolling bearings 78 , 80 towards the motor 54 until the rolling bearing 76 abuts against the wall 82 .

[0096] Therefore, the drive member 60 is maintained at a predetermined axial position relative to the frame 8 along the axis of the output shaft 58 (here the same as the axis of the drive member 60 ).

[0097] The coil spring 83 may, for example, be selected to apply a biasing force along the axis of the output shaft 58 that is greater than the force that the drive member 60 applies to the control member 62 to drive the control member 62 to move.

[0098] The movement of the control member 62 (here a rotation, producing the same rotation of the cylindrical lens 52) can thus be precisely controlled by a corresponding movement of the drive member 60 (which is itself driven by the motor 54). The control of the optical power (here the cylindrical correction) provided by the cylindrical lens 52 along the lens axis X is thus improved.

Claims

1. An optical device (2) comprising a lens (12; 52) and a control member (22; 62), the control member being configured such that movement of the control member (22) produces a change in the optical power provided along an optical axis (X) of the lens (12; 52), The optical device (2) further comprises a frame (8), a motor (14; 54) and a drive member (20), the motor (14; 54) comprising an output shaft (18) rotatably coupled to the drive member (20), the motor (14; 54) and the control member (22) being mounted in the frame (8) such that the drive member (20) and the control member (22) mechanically cooperate, in, The frame (8) defines a cavity (44) comprising a first cylindrical portion (45) having a first diameter and a second cylindrical portion (46) having a second diameter smaller than the first diameter, the second cylindrical portion (46) accommodating the threaded portion (21) of the drive member (20), The frame (9) comprises an annular wall (49) connecting the first cylindrical part (45) and the second cylindrical part (46). wherein the drive member (20) is rotatably mounted in the frame (8), wherein the optical device (2) comprises a biasing device (43) for maintaining the drive member (20) in a predetermined axial position along the axis of the output shaft and relative to the frame (8), wherein the drive member (20) is mounted in the frame (8) by means of at least one rolling bearing (38, 40), and wherein the biasing means (43) is in contact with the annular wall (49) to axially push the assembly of the drive member and rolling bearing against the wall (42) of the frame (8).

2. The optical device according to claim 1, wherein: The drive member (20) is press-fitted into the inner race of the at least one rolling bearing (38, 40).

3. The optical device according to claim 2, wherein: The biasing means (43) is arranged to axially push the outer ring of the at least one rolling bearing (38) against the wall (42).

4. The optical device according to claim 1, wherein: The drive member (20) is mounted in the frame (8) via the at least one rolling bearing (38) and the further rolling bearing (40), and wherein the biasing means (43) is interposed between the further rolling bearing (40) and the annular wall (49) so that the at least one rolling bearing (38) is pushed against the wall (42) of the frame (8).

5. The optical device according to claim 4, wherein: The at least one rolling bearing (38) and the further rolling bearing (40) are mounted on a first axial portion (23) of the drive member (20), wherein the drive member (20) is also mounted to the frame (8) via a further rolling bearing (48), the further rolling bearing (48) being mounted on a second axial portion (25) of the drive member (20), the first axial portion (23) and the second axial portion (25) being separated by the threaded portion (21) of the drive member (20).

6. The optical device according to claim 5, wherein: The cavity (44) comprises a third cylindrical portion (47) having a third diameter which is smaller than the second diameter, and wherein the further rolling bearing (48) is accommodated in the third cylindrical portion (47).

7. The optical device according to claim 4, wherein: The biasing means comprises a coil spring (83).

8. The optical device according to claim 4, wherein: The biasing means comprises a spring washer (43).

9. The optical device according to any one of claims 1 to 8, wherein: The biasing device (43; 83) is suitable for applying a biasing force along the axis of the output shaft that is greater than the force applied by the drive member (20; 60) to the control member (22; 62) to drive the control member (22; 62) to move.

10. An optical device according to any one of claims 1 to 8, further comprising an encoder (15; 55; 95) associated with the motor (14; 54; 94) for determining the angular position of the output shaft (18; 58).

11. The optical device according to any one of claims 1 to 8, wherein: The drive member is a worm (20; 60), wherein the control member is a gear (22; 62), and wherein the worm (20; 60) meshes with the gear (22; 62).

12. The optical device according to any one of claims 1 to 8, wherein: The lens is a cylindrical lens (52; 92) that is rotatable with the control member (62).

13. An optical device according to any one of claims 1 to 8, wherein: The lens (12) is adapted to provide a variable spherical power adjustable by rotation of the control member (22).

14. Optometry equipment comprising an optical device (2) according to any one of claims 1 to 8.

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