CN211404059U

CN211404059U - Focusing device and optical sensor

Info

Publication number: CN211404059U
Application number: CN201922141027.3U
Authority: CN
Inventors: 弗洛里安·施奈德; 格奥尔格·舍费尔; 约纳森·普法伊尔
Original assignee: Sick AG
Current assignee: Sick AG
Priority date: 2018-12-04
Filing date: 2019-12-04
Publication date: 2020-09-01
Anticipated expiration: 2029-12-04
Also published as: DE202018106910U1

Abstract

A focusing device for an optical system having a carrier and an objective arranged at the carrier, the focusing device comprising a first guide section configured for fastening to the carrier or designed integrally with the carrier, a second guide section forming a holder for the objective, at least one spring element forming an elastic connection of the first guide section to the second guide section, and an actuator for adjusting the second guide section relative to the first guide section along and against an adjustment direction, wherein the spring element is at least regionally planar, and an optical sensor. The spring element has at least one stiffening region in which a first surface portion of the spring element is bent along a bending edge relative to a second surface portion of the spring element.

Description

Focusing device and optical sensor

Technical Field

The utility model relates to a focusing device and optical sensor for optical system.

Background

A corresponding focusing arrangement is disclosed in US 4615585.

There is an effort to provide a focusing apparatus with a long service life and a high adjustment speed. However, the corresponding mechanical resilience can usually only be achieved using a complex design and a large number of components. This results in higher manufacturing costs.

It is therefore desirable to provide a focusing apparatus having a long service life and high adjustment speed, but low manufacturing costs.

This object is met by a focusing apparatus having the features of the embodiments of the present disclosure.

SUMMERY OF THE UTILITY MODEL

The utility model relates to a focusing device for optical system, this optical system have the carrier and arrange the objective in carrier department, and wherein focusing device includes:

a first guide portion configured for fastening to a carrier or designed to be integral with the carrier;

a second guide portion forming a holder for the objective lens;

at least one spring element forming a resilient connection of the first guide portion to the second guide portion; and

an actuator for adjusting the second guide section relative to the first guide section along and against an adjustment direction, wherein the at least one spring element is formed at least in some regions in a planar (area) manner.

Such focusing devices are used in sensors, scanners and other optical systems, and in particular serve to adjust the distance of an objective lens from a light receiving surface. This type of focusing apparatus is preferably suitable for an autofocus operation. The carrier may in particular be a housing or a base frame of the optical system. The spring element may be designed as a leaf spring.

According to the invention, the at least one spring element has at least one stiffening region in which the first surface section of the spring element is bent along the bending edge relative to the second surface section of the spring element. Due to the curved surface portion, the mechanical stability of the spring element is increased in the region of the reinforcement, which leads to an increase in the service life of the focusing device. In addition, the spring rate can be adjusted by bending of the surface portion. This possibility results from the invention, namely that the spring element is produced without compromising the stability by reducing the material thickness of the spring element or using a less expensive material.

In a focusing device according to the invention, the two guide portions may form a parallel guide together with the spring element for connection. The elastic connection of the guide portion via the spring element may be a direct or indirect connection depending on the application. This means that additional coupling elements may be provided. In order to further increase the stability and/or the spring rate of the at least one spring element, in addition to the first surface portion, at least one further surface portion may be curved along a curved edge relative to the second surface portion or relative to any other surface portion of the spring element.

Preferably, the actuator is configured as an electromagnetic actuator. For example, a moving coil actuator or motor may be provided to adjust the second guide portion relative to the first guide portion.

Preferably, the spring element is made of sheet metal, preferably a single-layer sheet metal. The sheet metal part can be produced particularly inexpensively and additionally has only a low weight. The spring element can in particular be made of an etched sheet metal part.

According to an embodiment of the invention, the bent edge extends transversely to the adjustment direction in the unloaded basic position of the spring element and/or extends obliquely to the adjustment direction in the loaded deflected position of the spring element. This is advantageous because the reinforcement is adapted to the prevailing direction of the load. It is preferably provided that the curved edge has a rectilinear extent and/or forms the outer edge of the spring element.

Another embodiment of the invention provides that the spring element has perforations and/or material weakening (material weakening) at the bent edge. This facilitates a positionally accurate bending of the first surface portion and thus simplifies the manufacture of the spring element. The perforations can be produced in a relatively simple manner by etching. Furthermore, a material weakening can be produced at the bending edge by a partially etched through hole of the spring element.

The first guide portion and the second guide portion may each be designed as a single-piece element of metal or plastic. This results in a particularly simple and inexpensive design.

Preferably, the spring element has a base part which comprises the second surface part and which, in the unloaded base position of the spring element, extends in a spring plate plane which extends transversely to the adjustment direction. The spring element can be designed in particular such that it extends in the spring plate plane in the unloaded base position away from the curved first surface section and away from further curved surface sections which may be present. The spring element is slightly bent out of the plane of the spring plate when the second guide part is linearly adjusted relative to the first guide part by means of the actuator.

The spring element may be frame-shaped to provide sufficient structural space for arranging the objective lens.

Lead-through holes (leadthroughs) for the fastening means can be provided in the respective corner regions of the frame-like spring elements. The lead-through can be manufactured in a simple manner by etching. The guide portion may be provided with a threaded hole aligned with the lead-in through hole of the frame-like spring element. The spring element can then be screwed to the first and second guide portions in a simple manner.

Preferably, provision is made for the second guide section to be arranged in or to extend into a central cutout (cutout) of the frame-like spring element. This design is particularly space saving.

For example, the frame-like spring element may comprise two fastening strips and two connecting strips, wherein each fastening strip contacts the guide portion at least substantially over the entire area and/or the connecting strips extend from one guide portion to the other guide portion. The reinforcing region of the spring element is preferably formed at one of the two connecting webs. The two connecting webs particularly preferably each have at least one reinforcing region. Each of the reinforced regions has at least one curved surface portion.

Another embodiment of the invention provides that the first guide section has a central introduction through hole and the second guide section is arranged in or extends into the central introduction through hole. This design takes up only little installation space. The first guide portion is preferably frame-shaped.

According to another embodiment of the invention, the first surface portion is curved at least 70 ° and at most 100 °, in particular about 90 °, with respect to the second surface portion. A particularly pronounced reinforcing effect is thus obtained.

A particular embodiment provides that the third surface portion of the spring element is likewise bent at least 70 ° and at most 100 °, in particular about 90 °, preferably in the same direction with respect to the second surface portion. The stability of the spring element is hereby further improved. In addition, a particularly high spring rate results.

The first surface portion and the third surface portion may be provided at oppositely arranged longitudinal sides of the strip-shaped portion of the spring element forming the second surface portion, in particular such that the strip-shaped portion has a U-shaped cross-section. A significant stability improvement can be achieved in a fast and simple manner by generating corresponding contours. The first surface portion and the third surface portion are preferably provided only in a central part area of the belt-like portion. It is preferable that the end portions remain free of surface portions bent at right angles so that they can be screwed to the guide portion without problems. As mentioned above, the first surface portion and the third surface portion may particularly be provided at oppositely arranged longitudinal sides of the connecting strip.

The spring element may have a further strip-shaped portion, wherein the fourth surface portion and the fifth surface portion of the spring element are each bent at least 70 ° and at most 100 °, in particular approximately 90 °, at oppositely disposed longitudinal sides of the further strip-shaped portion relative to a base plane of the further strip-shaped portion. This design is accompanied by particularly high stability. The strip-shaped portions are preferably arranged on opposite sides of the spring element and/or extend parallel to each other. The strip-shaped portions may form a connecting strip extending from one leading portion to the other leading portion.

At least one reinforcing surface portion of the spring element may be bent 180 ° relative to the base surface portion, in particular such that a double-layer portion is formed. The spring element may thus comprise a fully folded surface portion which further improves the stability. The reinforcement surface portion may be elongated and may extend transversely to the adjustment direction. The stiffening region may furthermore be elongate and may extend transversely to the elongate stiffening surface portion.

Preferably, the spring element is fastened to the first guide portion or the second guide portion in the region of the reinforcement surface portion. Thereby opposing excessive material tension in the fastening area. In order to enable the spring element to be fastened accordingly, an insertion through-hole for a fastening device (for example a screw) can be passed through the double-layer region. The spring element preferably comprises two oppositely arranged double-layered portions to ensure an improved fastening of the spring element at the two guide portions.

In the frame-like design of the spring element, the reinforcement surface portions as described above are preferably provided on two oppositely disposed frame sides, while the reinforcement areas as described above are provided on two other oppositely disposed frame sides. In the case of a construction in which the spring element has two fastening strips and two connecting strips, corresponding surface sections can be provided in particular at the fastening strips and/or corresponding stiffening and reinforcing regions can be provided at the connecting strips.

According to a further embodiment of the invention, at least two spring elements, which are formed at least in regions in a ground-like manner, are provided for the elastic connection of the first guide section to the second guide section, and each have a reinforcement region in which the first surface section is bent along a bending edge relative to the second surface section, the spring elements extending at a parallel spacing from one another. In the present embodiment, the objective lens held at the second guide portion is guided particularly reliably. The two parallel spring elements can be designed in particular as described above. The two spring elements are preferably of identical design. If desired, more than two spring elements extending parallel at a distance from one another can also be provided for the elastic connection of the guide section.

The spring elements may be attached at opposite end faces of the first guide portion and/or the second guide portion. This results in a particularly compact construction.

The invention also relates to an optical sensor, in particular a code reader, having a light emitter for emitting a radiation beam and/or having a light receiver for receiving a reception beam, having an objective as a converging optical element for emitting a radiation beam and/or for receiving a reception beam, and having a focusing device for adjusting the objective.

According to the present invention, the focusing device of the optical sensor is configured as described above, wherein the first guide portion is fastened to or formed integrally with the carrier of the optical sensor, and the objective lens is held in the second guide portion.

Optical sensors are used in many areas of industry for monitoring, protection and information recording. Particularly in logistics and automated production, a code reader (e.g. a bar code scanner or a camera system) serves to read the information contained in the code. For this purpose, the code reader can be mounted in a stationary manner at a conveyor belt, on which the objects carrying the code are conveyed past the code reader. Such systems typically must be able to reliably read codes over a relatively large depth of field. For this purpose, the focusing device sets the focal plane of the laser beam or of the objective lens of the barcode scanner to a corresponding distance value. It is difficult to design the focusing device to have a long service life, to be able to achieve high adjustment speeds and at the same time to be inexpensively produced.

The above-mentioned requirements can be met at the same time by parallel guidance of planar spring elements which are reinforced regionally by local bending of the surface section.

The design of the focusing device according to the present invention is to a large extent suitable for optical code readers, but is generally also suitable for other optical systems, such as digital cameras.

Further developments of the invention can also be seen from the dependent claims, the description and the drawings.

Drawings

Fig. 1 is a perspective view of a focusing device according to the invention for a code reader according to the invention;

FIG. 2 is an exploded view of the focusing apparatus shown in FIG. 1; and

FIG. 3 shows the spring element of the focusing apparatus shown in FIG. 1 in an unprocessed initial state.

Detailed Description

The invention will now be described, by way of example, with reference to the accompanying drawings.

The focusing device 11 shown in fig. 1 and 2 and designed according to an embodiment of the invention comprises a first guide portion 13 and a second guide portion 15, the first guide portion 13 and the second guide portion 15 preferably being designed as a single-piece element of metal or plastic, for example as an injection-molded part. The first guide part 13 is configured as a carrier for fastening to an optical system, such as a code reader (not shown), and is provided with fastening lugs 17 for this purpose. The first guide portion 13 can also be designed generally integrally with this carrier. A holder 19 for an objective lens (not shown) is formed at the second guide portion 15. As shown, the first guide portion 13 is frame-shaped and has a central lead-through hole 21, in which central lead-through hole 21 the second guide portion 15 is arranged.

The guide part 13 and the guide part 15 are connected elastically to one another via an arrangement of two planar spring elements 22 and 23 (fig. 2). The two

planar spring elements

22 and 23 are each screwed by means of screws 45 to the first guide section 13 in the region of the first end 31 and to the second guide section 15 in the region of the opposite second end 32. Which extend parallel at a distance from each other and together with the

guide portions

13 and 15 form parallel guides for the objective lens accommodated in the holder 19.

An actuator 35, which is only schematically illustrated, here in the form of a moving coil actuator of known design, serves for the adjustment of the second guide section 15 relative to the first guide section 13 in and against the adjustment direction V in dependence on control signals, thus adjusting the focal position of the objective lens relative to the image sensor (not illustrated).

The spring element 22 and the spring element 23 are frame-shaped and each have a central cut-out 37, which central cut-out 37 is aligned with the lead-in through hole 21 of the first guide portion 13. Specifically, the spring element 22 and the spring element 23 each have two fastening strips 39 and two connecting strips 40, wherein each fastening strip 39 contacts the guide portion 13 and the guide portion 15 over the entire area, and each connecting strip 40 extends from one guide portion 13 to the other guide portion 15. Lead-through holes 43 for screws 45 are provided in the corner regions 41 of the

spring elements

22 and 23.

As can be seen in fig. 2, the fastening strips 39 and the connecting strips 40 each form a base portion 47 of the associated spring element 22 and spring element 23, which defines a spring plate plane extending at right angles to the adjustment direction V.

Each of the

spring elements

22 and 23 has a stiffening region 50 in the respective central region of the connecting strip 40. Preferably, the reinforced area 50 extends over at least 25% and at most 80% of the longitudinal length of the connecting strip 40.

The respective first surface portion 51 in the stiffening region 50 is curved along a straight curved edge 54 relative to a second surface portion 54 belonging to the basic portion 47. Furthermore, the third surface portion 53 is curved with respect to the second surface portion 52 along a further rectilinear curved edge 54. In the embodiment shown, the first surface portion 51 and the third surface portion 53 are each bent by 90 ° with respect to the second surface portion 52 in order to create a respective U-shaped cross-section for the connecting strip 40 in the reinforcing region 50. As can be seen in fig. 2, the

spring elements

22 and 23 are fastened to the

guide portions

13 and 15 such that the

curved surface portions

51 and 53 of the

different spring elements

22 and 23 face each other.

The fastening strips 39 are double-layered in order to be able to attach the

spring elements

22 and 23 more stably to the

guide portions

13 and 15. The double-layer regions are each produced by bending the reinforcing surface portion 55 (fig. 3) by 180 ° relative to the base surface portion 57 of the base portion 47.

The manufacture of the spring element 22 and the spring element 23 will be described below with reference to fig. 3, which fig. 3 shows a single-layer sheet metal part 59 as an initial element of the spring element 22 or the spring element 23 (fig. 2). The first surface portion 51, the third surface portion 53 and the reinforcement surface portion 55 have not yet been bent with respect to the base portion 47. Corresponding perforations 61 are provided to define the curved edge 54. The perforations 61 may be created by etching.

To produce the spring element 22 or the spring element 23, the first surface portion 51 and the third surface portion 53 are bent through 90 °, while the reinforcement surface portion 55 is bent through 180 °. The first surface portion 51 and the third surface portion 53 bent through 90 ° create a reinforcement in the central area of the connecting strip 40, which improves the spring stiffness and stability. The reinforcing surface portion 55 bent through 180 ° results in an increased stability in the fastening area.

The

spring elements

22 and 23, which are reinforced and strengthened regionally but at a comparatively low manufacturing cost, provide a reliable and durable guide for the objective to be adjusted. The focusing device 11 according to the invention is suitable for any desired optical system with focus adjustment, in particular for optical code readers.

List of reference numerals

11 focusing device

13 first guide part

15 second guide part

17 fastening lug

19 holder

21 central lead-in through hole

22 spring element

23 spring element

31 first end

32 second end

35 actuator

37 center cut

39 fastening strip

40 connecting strip

41 corner region

43 lead-in through hole

45 screw

47 base part

50 reinforced area

51 first surface portion

52 second surface portion

53 third surface portion

54 curved edge

55 reinforcing the surface portion

57 base surface portion

59 sheet metal component

61 perforation

V regulates the direction.

Claims

1. Focusing device (11) for an optical system having a carrier and an objective lens arranged at the carrier, wherein the focusing device comprises:

a first guide portion (13) configured for fastening to the carrier or designed to be integral with the carrier;

a second guide portion (15) forming a holder for the objective lens;

at least one spring element (22, 23) forming an elastic connection of the first guide portion (13) to the second guide portion (15); and

an actuator (35) for adjusting the second guide section (15) relative to the first guide section (13) in and against an adjustment direction (V),

wherein the at least one spring element (22, 23) is at least partially planar,

it is characterized in that the preparation method is characterized in that,

the at least one spring element (22, 23) has at least one stiffening region (50), in which stiffening region (50) a first surface section (51) of the spring element (22, 23) is bent along a bending edge (54) relative to a second surface section (52) of the spring element (22, 23).

2. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the spring elements (22, 23) are made of sheet metal parts (59).

3. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the spring elements (22, 23) are made of a single-layer sheet metal part (59).

4. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the bent edge (54) extends transversely to the adjustment direction (V) in the unloaded base position of the spring element (22, 23).

5. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the spring element (22, 23) has perforations (61) and/or a material weakening at the bent edge (54).

6. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the first guide portion (13) and the second guide portion (15) are each designed as a single-piece element of metal or plastic.

7. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the spring element (22, 23) has a base portion (47), the base portion (47) comprising the second surface portion (52) and the base portion (47) extending in a spring leaf plane extending transversely to the adjustment direction (V) in an unloaded base position of the spring element (22, 23).

8. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the spring elements (22, 23) are frame-shaped.

9. The focusing apparatus of claim 8,

it is characterized in that the preparation method is characterized in that,

lead-through holes (43) for fastening means (45) are provided in the respective corner regions (41) of the frame-like spring elements (22, 23).

10. The focusing apparatus of claim 9,

it is characterized in that the preparation method is characterized in that,

the second guide portion (15) is arranged in or extends into a central cutout (37) of the frame-like spring element (22, 23).

11. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the first guide portion (13) has a central lead-through hole (21) and the second guide portion (15) is arranged in or extends into the central lead-through hole (21).

12. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the first surface portion (51) is curved at least 70 ° and at most 100 ° relative to the second surface portion (52).

13. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the first surface portion (51) is bent 90 ° with respect to the second surface portion (52).

14. The focusing apparatus of claim 12,

it is characterized in that the preparation method is characterized in that,

the third surface portion (53) of the spring element (22, 23) is likewise bent at least 70 ° and at most 100 ° in the same direction with respect to the second surface portion (52).

15. The focusing apparatus of claim 12,

it is characterized in that the preparation method is characterized in that,

the third surface portion (53) of the spring element (22, 23) is likewise bent by 90 ° in the same direction with respect to the second surface portion (52).

16. The focusing apparatus of claim 14,

it is characterized in that the preparation method is characterized in that,

the first surface portion (51) and the third surface portion (53) are arranged at oppositely arranged longitudinal sides of a strip-shaped portion of the spring element (22, 23) forming the second surface portion (52), such that the strip-shaped portion has a U-shaped cross-section.

17. The focusing apparatus of claim 16,

it is characterized in that the preparation method is characterized in that,

the spring element (22, 23) has a further strip-shaped portion, wherein the fourth surface portion and the fifth surface portion of the spring element (22, 23) are each bent at least 70 ° and at most 100 ° at oppositely disposed longitudinal sides of the further strip-shaped portion with respect to a base plane of the further strip-shaped portion.

18. The focusing apparatus of claim 16,

it is characterized in that the preparation method is characterized in that,

the spring element (22, 23) has a further strip-shaped portion, wherein the fourth surface portion and the fifth surface portion of the spring element (22, 23) are each bent by 90 ° at oppositely disposed longitudinal sides of the further strip-shaped portion with respect to a base plane of the further strip-shaped portion.

19. The focusing apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

at least one reinforcing surface portion (55) of the spring element is bent 180 ° relative to the base surface portion (57) such that a double-layer portion is formed.

20. The focusing apparatus of claim 19,

it is characterized in that the preparation method is characterized in that,

the spring element (22, 23) is fastened to the first guide portion (13) or the second guide portion (15) in the region of the reinforcement surface portion (55).

21. A focusing apparatus according to any of claims 1 to 20,

it is characterized in that the preparation method is characterized in that,

at least two spring elements (22, 23) which are formed at least in regions in a ground-like manner are provided for the elastic connection of the first guide part (13) to the second guide part (15), and the at least two spring elements (22, 23) each have a reinforcing region (50), in which reinforcing region (50) the first surface section (51) is bent along the bending edge (54) relative to the second surface section (52), wherein the spring elements (22, 23) extend at a parallel distance from one another.

22. The focusing apparatus of claim 21,

it is characterized in that the preparation method is characterized in that,

the spring elements (22, 23) are attached at opposite end faces of the first guide portion (13) and/or the second guide portion (15).

23. An optical sensor having a light emitter for emitting an emission light beam and/or having a light receiver for receiving a reception light beam, having an objective lens as a converging optics for the emission light beam and/or for the reception light beam, and having a focusing device (11) for adjusting the objective lens,

it is characterized in that the preparation method is characterized in that,

the focusing device is configured according to any of claims 1 to 22, wherein the first guide portion (13) is fastened to or formed integrally with a carrier of the optical sensor, and wherein the objective lens is held in the second guide portion (15).