haptic devices

Abstract

The haptic device (1) comprises a movable surface (15), an actuator (2) for operating the movable surface (15), and an elastic abutment (7). The actuator (2) is disposed between the movable surface (15) and the elastic abutment (7), and is configured such that, when a force (F) acts on the movable surface (15), a stiffness (S) of the actuator (2) has a first value (S1) that is less than a first force value (F1) and has a greater value (S2) that is greater than the first force value (F1), and a spring constant of the abutment (7) has a value (D) that is between the first stiffness value (S1) and the second stiffness value (S2).

Description

[Technical Field]

[0001] The present invention relates to a tactile device for generating tactile signals. Such a device comprises an actuator for generating a movement of a moving element, for example configured as a touch-sensitive surface or the tip of a pen-like device. The actuator is for example a piezoelectric or electromagnetic actuator.

[0002] A haptic device may be configured to generate a haptic signal, for example, when touched. A haptic device may be configured as, for example, a touchscreen, a trackpad, a push button, or a stylus (pen-like device). In particular, a haptic device may be used in an automobile or a computer.

[0003] DE 10 2015 117 262 A1 discloses a haptic device with a piezoelectric actuator. US 8,416,066 B2 and WO 2020 / 011526 A1 both show a stylus.

[0004] In such devices, on the one hand, it is necessary to design a flexible moving surface to allow effective operation by the actuator, and on the other hand, the actuator may be damaged by excessive external forces acting on the moving surface, for example in the case of a collision or a drop.

[0005] It is known to provide mechanical stop elements to limit the movement of a haptic device to protect against excessive force, for example, US 9,379,305 B2 discloses a stop element on a housing plate, US 2012 / 0248935 A1 discloses a stop element on a base plate, and US 2021 / 0280768 A1 discloses a thrust plate with a movement limit. Summary of the Invention

[0006] The object of the present invention is to provide a haptic device with improved properties, in particular protection against overloads should be achieved while maintaining the haptic functionality.

[0007] According to a first aspect of the present disclosure, a haptic device has a movable surface and an actuator for operating the movable surface. The haptic device is configured, for example, as a touch screen or a pen-type device (stylus). The haptic device may be configured to be held by a user, for example, like a stylus. Such devices are at a particularly high risk of damage from dropping the device.

[0008] A movable surface is in particular an external surface that can be configured to output a tactile signal. The surface is, for example, the surface of a touchscreen or the outer surface of a movable element such as the tip of a stylus. The surface can also be directly the surface of an actuator. The actuator comprises, for example, a piezoelectric or electromagnetic transducer element that converts an electrical signal into a movement or deformation of a transducer element.

[0009] The actuator may alternatively or additionally be configured as a sensor configured to detect external forces exerted on the movable surface. In particular, the actuator may be configured simultaneously as an actuator and a sensor. The elements of the haptic device and the actuator may remain unchanged in their sensor function.

[0010] The actuator is arranged between the movable surface and the elastic abutment. The abutment is configured, in particular, to support the actuator and generate a reaction force when the actuator expands. By appropriately adjusting the stiffness behavior of the actuator and the spring constant of the abutment, it can be achieved that the actuator is better protected against overload. For this purpose, the actuator is configured so that its stiffness takes on different values ​​depending on the value of an external force acting on the movable surface. When the force value is below a first force value, the stiffness of the actuator has a first value. When the force value is above the force value, the stiffness of the actuator has a second value greater than the first value. The spring constant of the abutment lies between the first stiffness value and the second stiffness value.

[0011] For example, the spring constant D is at least 1.5 times greater than the first stiffness. For example, the spring constant is at least 100 N / mm greater than the first stiffness of the actuator. For example, the spring constant is at most 0.75 times greater than the second stiffness. For example, the spring constant is at least 100 N / mm less than the second stiffness of the actuator.

[0012] In this way, the actuator can be sufficiently compressible below the first force value to ensure tactile functionality. In particular, the operating range of the haptic device can be below the first force value. The elastic abutment does not impair or only slightly impairs functionality in the operating range due to its larger spring constant. Above the first force value, the abutment's function can begin to function because the spring constant is smaller than the actuator's stiffness. As a result, the abutment deforms more and the actuator's compression decreases.

[0013] For example, the second stiffness value is at least twice as large as the first stiffness value. The second stiffness value can also be at least four times as large as the first stiffness value.

[0014] The abutment is, for example, connected to an edge of the housing of the haptic device. The abutment can also be configured as an integral part of the housing. The abutment can be supported on only one side, for example connected to the housing on one side. For example, the abutment is configured in the form of a bar. The abutment can also be supported circumferentially or on two opposite sides. The abutment can also have different designs, for example a plate that is elastically mounted by spring elements.

[0015] The haptic device can have a path limitation of the movable surface in the direction of the actuator, which is determined by a mechanical stop. For example, the stop is formed by the housing or a part fixed to the housing. The path limitation, i.e., the maximum path of the surface from the rest position in the direction of the actuator, can be greater than the compression of the actuator when the stop is reached. The compression of the actuator here is the change in thickness of the actuator relative to the thickness of the actuator in the absence of the action of an external force.

[0016] For example, the compression of the actuator when reaching the stop is less than half of the path limit, e.g., the path limit is a value between 0.2 and 0.5 mm, and the compression of the actuator is less than 0.15 mm.

[0017] The change in the stiffness of the actuator can be achieved, for example, by at least one support element that is supported on the transducer element of the actuator when a first force value is reached. For example, the support element is a part of a stiffening element that stiffens the movement of the actuator. The stiffening element can be, for example, in the form of a bracket. The support element can be configured as a protrusion of the stiffening element toward the actuator. When the first force value is reached, the support element can mechanically impact the transducer. The support element can, for example, be an integral part of the stiffening element or be attached to the stiffening element. It is also possible for the support element to be formed on the transducer element.

[0018] According to a further aspect of the present disclosure, there is disclosed a method of manufacturing the above-described haptic device, wherein an actuator having two preset stiffness values ​​is provided, and a resilient abutment is selected to have a spring constant that is between the stiffness values ​​of the actuator.

[0019] Furthermore, the maximum compression of the actuator can be determined, i.e., the compression that can still be tolerated without damaging the actuator. The path limits of the moving surface can be defined by mechanical stops. In this case, the spring constant is selected so that when the path limits are reached, the compression of the actuator is less than the maximum compression of the actuator.

[0020] The present invention comprises several aspects, particularly devices and methods, and features, characteristics and embodiments described with respect to one aspect apply to other aspects as well, as appropriate.

[0021] Furthermore, the description of the subject matter specified herein is not limited to particular embodiments, but rather the features of the individual embodiments can be combined with each other where technically meaningful. [Brief explanation of the drawings]

[0022] In the following, the aspects described herein are explained in more detail using schematic examples. [Figure 1] FIG. 1 is a diagram illustrating a cross-sectional view of one embodiment of a haptic device. [Figure 2] FIG. 2 shows a displacement-force diagram of an embodiment of a haptic device. [Figure 3] FIG. 3 shows a cross-sectional view of a further embodiment of a haptic device.

[0023] Preferably, in the following figures, the same reference numerals refer to functionally or structurally corresponding parts of the various embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 shows a cross section of an embodiment of a haptic device 1. The haptic device 1 is pen-shaped and is also called a stylus. The haptic device 1 can be used as an input and / or output device, for example, in virtual reality or augmented reality applications. The haptic device 1 can generate a particular haptic impression for the user. For example, it can create the impression that the haptic device 1 is moving over a surface. It can also create a particular impression of the surface texture.

[0025] For this purpose, the haptic device 1 comprises an actuator 2 configured to generate movements, motions or movements that give a haptic impression to the user. In particular, the actuator 2 is configured to generate vibrations.

[0026] The actuator 2 is configured to generate a movement of the movable surface 15. The movable surface 15 may be the outer surface of the movable element 3. In particular, the movable surface 15 is configured to be movable relative to the housing 11 of the haptic device 1. For example, the movable element 3 includes a tip 4 of the haptic device 1. The movable element 3 may be formed of one or more parts. In some sections, the movable element 3 has the shape of a rod, in particular a shaft. The tip 4 may be an integral part of the rod-shaped region. The tip 4 can be moved over the surface, and the movement of the tip 4 can generate an impression of the surface texture for the user. It is also possible to arrange the movable surface 15 and the movable element 3 on a stylus so that the user can directly touch the movable surface 15. In this case, for example, the movable surface 15 is arranged on the side of the haptic device 1 and the actuator 2 is rotated and oriented accordingly.

[0027] The movement of the actuator 2 is transmitted to the movable element 3 via a first contact surface 5. A second contact surface 6 of the actuator 2 is in contact with a resilient abutment 7. When the actuator 2 expands, a counter force acts on the contact surfaces 5, 6. The resilient abutment 7 may be fixedly connected to the housing 11 or may be an integral part of the housing 11.

[0028] The actuator 2 comprises a transducer element 8 which, when an electrical signal is applied, performs a movement, such as a deformation, expansion or contraction. For example, the transducer element 8 is configured as a piezoelectric element. It may be a piezoceramic element. In particular, it may be a multilayer element. It is also possible to design the transducer element 8 in another way, for example as an electromagnetic actuator, such as a voice coil (moving coil actuator).

[0029] The actuator 2 also comprises a stiffening element 9 for amplifying the magnitude of the movement, in particular the vibration. The stiffening element 9 is configured, for example, as a sheet metal. The stiffening element 9 is attached to the edge of the transducer element 3. In a central region, the stiffening element 9 comprises a first contact surface 5 configured to act on the movable element 3. The central region of the stiffening element 9 is spaced apart from the transducer element 8 and can move relative to it. The movement of the transducer element 8 along the axial direction can be stiffened by the stiffening element 9. The stiffening element 9 is configured, for example, in the form of a bracket or a truncated cone.

[0030] The actuator 2 has, on the side facing the transducer element 9, a further stiffening element 10. The further stiffening element 10 comprises a contact surface 6 for the abutment 7.

[0031] The distance between the contact surfaces 5, 6 defines the thickness d of the actuator 2. The compression Δd of the actuator 2 is the change in thickness compared to the thickness when there is no external force acting on the movable element 6, i.e. when the haptic device is at rest. When the actuator 2 vibrates during actuation, the thickness is the average thickness of the actuator.

[0032] For example, excessive force F acting on the movable surface 15 when the haptic device 1 is bumped or dropped can damage the actuator 2. For example, the actuator 2 can collide with the tip 4 if the tip 4 is dropped. In particular, damage can occur if the compression Δd of the actuator 2 is too strong. For example, excessive compression Δd can damage the stiffening elements 9, 10 or cause failure of their attachment to the transducer elements 8.

[0033] In order to limit the compression, the haptic device 1 can have mechanical stops 14 for limiting the maximum path of the movable element 3 and the movable surface 15 in the direction of the actuator 2, on the one hand. However, it turns out that a path limitation that functions reliably before damaging the actuator 2, on the other hand, and at the same time does not impair the haptic function, is often technically impossible to achieve with such stops 14. For example, it may be necessary that the stops 14 must allow a path of the movable element 3 that is significantly larger than the maximum allowable compression Δdmax of the actuator 2. For example, the maximum path xmax of the movable surface 15 and the movable element 3 is 0.3 mm and the maximum allowable compression Δdmax is 0.15 mm.

[0034] In order to limit the compression of the actuator 1, the abutment 7 is configured as a spring element. For example, the abutment 7 is configured as a leaf spring. The abutment 7 has, for example, a bar shape. The abutment 7 is fixed to an edge of the housing 11. For example, the abutment 7 is fixed to only one side of the housing 11. The abutment 7 may be an integral part of the housing 11. It is also possible to fix the abutment 7 to the housing 11. For example, the abutment 7 is made of metal.

[0035] The abutment portion 7 has a spring constant D that is greater than the stiffness of the actuator 2 in the intended operating range. For example, the spring constant D is 300 N / mm.

[0036] For example, the actuator 2 has a stiffness S1 within its operating range. In particular, the stiffness of the actuator is a differential stiffness in the form of the derivative of the normal force on the contact surfaces 5, 6 as a function of the distance d between them. The stiffness can have a constant value within a certain distance range. It is also possible for the stiffness to vary continuously.

[0037] The intended operating range is defined by a first value F1 of force applied to the movable surface 15. As long as the force is less than or equal to the value F1, the haptic device is within the operating range in which a haptic signal should be output.

[0038] Since the stiffness S1 of the actuator 2 is lower than the spring constant D of the abutment 7 in the operating range, the actuator 2 is mainly compressed when a force is applied, while the abutment 7 is only slightly deformed. The fact that the spring constant D of the abutment 7 is greater than the stiffness S1 of the actuator 2 in the operating range means that the functionality of the actuator 2 is not impaired or is only slightly impaired. For example, the spring constant D is at least 100 N / mm greater than the first stiffness S1 of the actuator 2. For example, the spring constant D is at least 1.5 times greater than the first stiffness S1.

[0039] The actuator 2 is configured such that, above a first force value F1, the stiffness of the actuator 2 has a value S2 that is greater than the spring constant of the abutment 7. In this way, the compression of the actuator 2 is reduced and a greater deformation of the abutment 7 is achieved.

[0040] To adjust the stiffness in different force ranges, the actuator 1 has one or more support elements 12, 13. For example, the support elements 12, 13 are arranged closer to the transducer element 8 than the respective contact surfaces 5, 6. The support elements 12, 13 can be integrated into the reinforcement elements 9, 10. For example, the support elements 12, 13 are formed as recesses in the reinforcement elements 9, 10, reducing the distance of the reinforcement elements 9, 10 from the transducer element 8. For example, the distance is reduced in the vicinity of the contact surfaces 5, 6.

[0041] When an external force from a first value F1 acts on the movable element 3, thus putting the actuator under a certain compression, the support elements 12, 13 come into contact with the transducer element 8. This causes the stiffness of the actuator 1 to increase from a first value S1 to a second value S2, and therefore makes it more difficult to compress the actuator 1 further.

[0042] The value S2 is greater than the spring constant D. For example, S2 is at least twice as large as S1, e.g., S2 > 2 x S1. S2 may be at least four times as large as S1, e.g., S2 > 4 x S1. In this way, it can be ensured that further compression of the actuator 2 is significantly reduced when the first force value F1 is exceeded.

[0043] When the movable element 3 comes into contact with the stopper 14, a path restriction acts between the movable element 3 and the housing 11. For example, the stopper 14 acts on the movable element 3 with a second force F2=50 N. The stiffness S3 of the path restriction, which is essentially determined by the deformability of the movable element 3 and the stopper 14, is greater than S2. For example, the stiffness S3 is at least twice as large as S2.

[0044] Overall, by using the abutment 7 and adjusting the stiffness value of the actuator 3, it is possible to make the path of the movable surface 15 large enough until the path limit comes into play, so that the tactile function is not impaired and at the same time effective protection of the actuator 2 against overload is achieved.

[0045] In a particular embodiment, the haptic device 1 is configured as a stylus, as shown in particular in Figure 1. The actuator 2 is configured as a piezoelectric actuator. For example, the actuator has dimensions of 7 x 3.75 x 1.3 mm (length x width x height). The increase in stiffness of the actuator 2 is achieved, for example, with a first force F1 = 5 N.

[0046] 2 shows a displacement-force diagram of the movement or compression of the various components of the haptic device, where the path x is given in mm and the external force F acting on the movable element 6 or tip 4 is given in N.

[0047] In the actuation range, i.e., when a force F less than or equal to F is applied, the stiffness S1 of the actuator 2 is at a low value, resulting in a high compression of the actuator 2. The slope of the compression curve Δd is essentially determined by the stiffness S1.

[0048] When a force F greater than or equal to F1 is applied, the stiffness of the actuator 2 increases. This can be achieved by the support elements 12, 13 abutting against the transducer element 8. This can also be achieved by other geometric shapes of the reinforcing elements 9, 10. When a force greater than F1 is applied, the stiffness of the actuator 2 becomes greater than the spring constant of the abutment 7. The compression Δd of the actuator 2 only increases slightly in this region as the force increases. Instead, the abutment 7 becomes more deformed.

[0049] When a force value F2 is reached, the mechanical stop 14 acts on the movable element 3. The compression Δd of the actuator 2 only increases minimally when the force increases. In particular, even when very large forces are applied, the compression Δd remains below a maximum compression Δd of, for example, 0.15 mm, even if the path of the movable part 3 to the stop is significantly larger, for example, 0.3 mm or more.

[0050] The diagram also shows the course of deformation xW of the abutment 7 in the direction of force F, in particular the movement of the central region of the abutment 7 against which the second contact surface 6 abuts. Furthermore, the path xB of the movable surface 15 or of the movable element 3 in the direction of force F is shown. At forces above F2, the movable element 3 comes into contact with the stop 14, so that further displacement can only be achieved by deforming the component. For example, bending or deformation of the movable surface 15 or of the movable element 3 or of the stop 14 occurs here.

[0051] Also shown is the force FA acting on the actuator 3 and the abutment 7. Here again it can be seen that the force FA is only slightly increased from the value F2 of the external force F by the stopper.

[0052] The compressive force on the actuator can be limited by the elastic abutment 7 and the setting of the stiffness values ​​S1 and S2 of the actuator 2. For example, even if an external force of 400 N acts on the movable element 3, the compressive force on the actuator 2 remains less than 80 N.

[0053] FIG. 3 shows a further embodiment of the haptic device 1. Here too, the actuator 2 is arranged between the movable element 3 and a resilient abutment 7. The abutment 7 is held at the edge of the housing 11. For example, the abutment 7 is in the form of a bar or a disk. The actuator 2 may be configured as in the embodiment shown in FIG. 1. In particular, the actuator 2 is configured to increase its stiffness at a first force value F1. For this purpose, the actuator 2 comprises support elements 12, 13 which may be integrated into the reinforcing elements 8, 9.

[0054] In contrast to the embodiment shown in Fig. 3, the haptic device 1 is not configured in the form of a stylus but rather has a tactile touch surface, e.g. a touchscreen or a push button. In particular, the movable element 3 has a movable surface 15 designed to be touched by a user with a finger or an input device in order to input a signal or receive a response. For example, the user makes an input by pressing with a finger or receives a tactile signal, in particular a tactile response to an input.

[0055] Here too, a mechanical stop 14 is used to limit the path of the movable element 3. For example, the path limit is xB=0.3 mm. The path limit is reached, for example, with a force F2=50 N.

[0056] For example, the actuator 2 has component dimensions of 12 x 4 x 1.75 mm (length x width x height). The first stiffness S1 of the actuator is, for example, 100 N / mm. At a given external force F of a first value F1, the stiffness of the actuator increases, for example, to a value S2 = 1800 N / mm. For example, the first value F1 is 8 N. The spring constant D of the abutment 7 lies between the stiffness values ​​S1 and S2. For example, the spring constant D is 300 N / mm. [Explanation of symbols]

[0057] 1. Haptic Devices (Haptik-Vorrichtung) 2 Actuator 3. Movable Element 4. Spitze 5 First contact surface 6 Second contact surface 7 Contact part (Widerlager) 8 Transducer element (Wandler element) 9 Reinforcing elements 10 Further reinforcing elements 11 Housing (Gehaeuse) 12 Supporting elements (Stuetzelement) 13 Support element (Stuetzelement) 14 Stopper (Anschlag) 15 Movable surfaces d Thickness (Dicke) Δd Compression Δdmax Maximal Compression S Stiffness S1 First stiffness value (erster Steifigkeitswert) S2 Second stiffness value (zweiter Steifigkeitswert) D Spring constant (Federkonstante) F1 First Force Value F2 Second force value (zweiter Kraftwert) xW Contact path (Weg Widerlager) xB Moving part path (Weg bewegliches Teil) F. Force from Outside (Kraft von aussen) FA Force acting on the actuator (Kraft auf Aktuator) S3 Rigid stopper xmax Route Restriction (Wegbegrenzung)

Claims

1. 1. A haptic device, comprising: A movable surface; an actuator for operating the movable surface; an elastic contact portion; the actuator is disposed between the movable surface and the elastic abutment; a stiffness of the actuator configured to have a first stiffness value when the force is below a first force value and a second stiffness value when the force is above the first force value when the force is applied to the movable surface; a spring constant of the elastic contact portion having a value between the first stiffness value and the second stiffness value; a path restriction of the movable surface in the direction of the actuator; the path limit is defined by a mechanical stop; the compression of the actuator is less than the path limit when the stop is reached; Tactile device.

2. the second stiffness value is at least twice as large as the first stiffness value; The haptic device of claim 1 .

3. the spring constant is at least 1.5 times as great as the first stiffness value and at most 0.75 times as great as the second stiffness value; The haptic device of claim 1 .

4. the actuator comprises a transducer element and at least one support element, the support element being supported by the transducer element when the first force value is reached; The haptic device of claim 1 .

5. the actuator has at least one stiffening element that stiffens the actuator's action; The reinforcing element includes the support element. The haptic device according to claim 4 .

6. the elastic abutment is connected to or is an integral part of the housing of the haptic device; The haptic device of claim 1 .

7. The elastic abutment is configured as a bar and is supported on one side. The haptic device of claim 1 .

8. It is pen-shaped, The haptic device of claim 1 .

9. the actuator is configured to act on a movable element, the movable element being configured to be rod-shaped in at least some regions; The haptic device of claim 1 .

10. configured to be maintained by the user; The haptic device of claim 1 .

11. The actuator is also configured as a sensor. The haptic device of claim 1 .

12. the movable surface is configured to be touched by a user; The haptic device of claim 1 .

13. A haptic device, comprising: A movable surface; an actuator for operating the movable surface; an elastic contact portion; the actuator is disposed between the movable surface and the elastic abutment; a stiffness of the actuator configured to have a first stiffness value when the force is below a first force value and a second stiffness value when the force is above the first force value when the force is applied to the movable surface; a spring constant of the elastic contact portion having a value between the first stiffness value and the second stiffness value; the actuator comprises a transducer element and at least one support element, the support element being supported by the transducer element when the first force value is reached; the actuator has at least one stiffening element that stiffens the actuator's action; The reinforcing element includes the support element. Tactile device.

14. A method for manufacturing a haptic device according to any one of claims 1 to 13, comprising the steps of: providing the actuator with two preset stiffness values; the elastic abutment has a spring constant selected such that the spring constant is between the first stiffness value and the second stiffness value of the actuator; Identifying a maximum compression of the actuator; defining a path limit for the movable surface by a mechanical stop; selecting the spring constant such that upon reaching the mechanical stop, the compression of the actuator is less than the maximum compression of the actuator; method.

Images