Method for generating haptic feedback

Abstract

The invention relates to a method for generating haptic feedback on a display area which can be operated by finger movements, wherein the position of a finger on the display area (3) is sensed and the friction coefficient between the finger and the display area is adjusted in dependence on the position. The method according to the invention is characterized in that the resting position of two fingers is determined and the friction between each of the fingers and the display area is varied in dependence on the distance from the resting position of the fingers which simultaneously touch the surface.

Description

Technical Field

[0001] This invention relates to a method for generating haptic feedback on a display area operable by finger movements. Furthermore, this invention relates to an apparatus having display and operating surfaces for performing this method. Background Technology

[0002] Tactile feedback, particularly on touch displays, is disclosed in the prior art through vibrations in a display area operable by finger movement. For example, US 2014 / 0327839 A1 describes a corresponding contact surface equipped with an actuator for generating vibrations. The actuator is herein designed as a piezoelectric film.

[0003] US 2019 / 0345185 A1 also discloses a touch-operable display area, in which the surface is subjected to vibrations in the ultrasonic range by actuators, in this case, piezoelectric actuators, distributed around the display area. The frictional force resisting finger movement can be adjusted by changing the frequency. Therefore, the coefficient of friction between the finger and the surface can be adjusted based on the finger position sensed on the operating surface. Summary of the Invention

[0004] The objective of this invention is to utilize this adjustability of friction between the finger and the display surface to optimize tactile feedback when manipulating the displayed object.

[0005] According to the invention, this task is accomplished by a method having the following characteristics. Advantageous designs and improvements to this method arise from other alternative embodiments. Furthermore, the invention proposes a device with a display and operating surface, which is configured to perform this method and is particularly suitable for placement in a vehicle.

[0006] The method for generating tactile feedback on a display area operable by finger movement according to the present invention specifies that, similar to what has been described in the prior art, the coefficient of friction between the finger and the display area is adjusted, for example, by generating surface vibration of the display area through at least one actuator. The invention specifies that the resting positions of two fingers are determined, and the friction between each finger and the display area is changed according to the change in distance of the fingers simultaneously touching the surface from the resting positions. Here, it is specified that the gradient determining the change in friction (hereinafter referred to as the friction gradient) can be the same between one finger and the surface and between the other finger and the surface, but it can also be different. The resting position refers to a position on the display area touched by a finger before a gesture such as a zooming gesture, grasping gesture, or swiping gesture, and the finger then performs the corresponding gesture without withdrawing from the display area.

[0007] In the design of this invention, frictional changes are caused by alterations in electrostatic charge and / or surface vibrations applied to the display area by at least one actuator. In particular, the combination of the two systems advantageously allows for a wide range of frictional adjustments.

[0008] In an advantageous embodiment, friction increases at least locally as the distance of the finger from the resting position changes. This provides initial tactile feedback, as the change in friction or the actual object size can now be inferred purely by touch from the varying friction, without the need for visual feedback involving the object. The friction between the finger and the display surface is preferably at its minimum along the overall curve at the finger resting position. As the distance from the resting position changes—that is, as the distance increases or decreases relative to the resting position—friction increases in a manner corresponding to a predetermined friction gradient. Since the resting position represents, to some extent, a friction valley, it allows the user to easily locate the finger's resting position.

[0009] In an alternative implementation, friction decreases as the finger moves further from its resting position, such that the finger reaches its maximum value at the resting position along the overall curve. The resting position of the finger can thus be located tactilely, as it is the area of ​​maximum friction, i.e., the peak of friction.

[0010] In an advantageous embodiment of the method, as a finger is detected approaching the operable display area, the frictional resistance between the finger and the display area is pre-adjusted to an initial frictional value by changing the amplitude and / or frequency of surface vibrations or electrostatic charge. The display area is thus advantageously provided in advance by pre-setting parameters that determine the friction, thereby providing the desired frictional resistance directly and without delay between the finger and the display area upon finger touch.

[0011] In a preferred embodiment, as each finger reaches a predetermined distance change from its resting position, the friction gradient is adjusted to be the opposite of the gradient that was effective until the distance change was reached; that is, a gradient with an inverse slope. Accordingly, a positive friction gradient has a positive slope, and a negative friction gradient has a negative slope. As the predetermined distance change is reached, the friction gradient becomes negative if it was positive until the predetermined distance change was reached, or becomes positive if it was negative until the predetermined distance change was reached. The user receives significant feedback as they scan over the predetermined distance change point, which is felt, for example, as a phase or pause in the zooming process. Corresponding to a mechanical switch (where the force initially increases upon operation and then decreases at a pause position), the pause position is simulated using a friction ascending gradient and a friction descending gradient.

[0012] In a preferred improvement, the friction curve repeats from a second distance change that is higher than a predetermined value until the second distance change. The first distance change is preferably equal to the second distance change, thus repeating the process multiple times, resulting in the same wavy or sawtooth friction curve, which advantageously allows the user to perceive the successive stages or pauses in the scaling process.

[0013] In this method, with each repetition, the slopes of the frictional ascending gradient and / or frictional descending gradient are increased or decreased; that is, the gradients become steeper or gentler. Additionally or alternatively, the maximum value of the repeated portion of the friction curve is altered. Besides the stuttering during the repetition of the friction curve, the overall friction level is increased by increasing the frictional gradient and / or the maximum value, thereby allowing the user to perceive the actual scaling level tactilely, in addition to the stuttering. Similarly, the overall friction level can be decreased by decreasing the gradient during stuttering repetitions, i.e., smoothing it out and / or decreasing the maximum value, thereby tactilely displaying the distance to the relevant scaling area to the user, for example.

[0014] In an advantageous embodiment, the change in distance of the finger touching the surface relative to the resting position is caused by the rotation of the finger about the center of rotation on the display area. With this arrangement, tactile feedback can be generated, for example, when operating a rotation adjuster displayed on the display device or when rotating a navigation map. As the finger moves away from the resting position due to rotation about the center of rotation on the display device, frictional resistance increases, so that the zero point, represented by a friction valley or maximum friction value, can be tactilely perceived at the resting position.

[0015] In an alternative implementation, object scaling is achieved through changes in the distance between the fingers. Corresponding to the change in distance relative to the resting position, the object on the display area is enlarged or reduced. From the resting position, the friction between the finger and the display area is preferably increased, but can also be decreased depending on the application. The user feels the change in friction during the scaling process, thus receiving tactile feedback on the effectiveness of their operation without visual contact.

[0016] In an additional or alternative improvement to the method according to the invention, the change in distance between the fingers touching the surface and their resting positions is caused by radially opposite movements for grasping the object, wherein the frictional gradient between the finger placed in the display area and the finger placed closer to the object reference point, such as the center of gravity or geometric center, is adjusted to be greater than the frictional gradient between the display area and the other finger. The object displayed in the display area is grasped such that both fingers move toward the object. Once the object is in place with the two fingers, the object is considered to be grasped and can be manipulated on the display area by means of the fingers, i.e., moved, for example. If the distance between the resting position and the object reference point is of different magnitudes, the frictional gradient is adjusted such that the finger resting further away from the geometric center of the object approaches the object boundary more quickly, while the finger closer approaches more slowly, so that the object is touched by both fingers simultaneously. In the case of a frictional gradient that increases from the resting position, the frictional gradient between the display area and the finger further away from the reference point is therefore chosen to be gentler than the frictional gradient between the display area and the other finger. Ideally, this is relative to the hand pointing at the object, i.e., two fingers simultaneously touching and virtually pinching the object's boundaries. With a reduced friction gradient from the resting position, the friction gradient between the display area and the finger resting closer to the object reference point is adjusted to be smaller than the friction gradient between the display area and the other finger. In a modified solution, a wavy or sawtooth friction curve can be superimposed on the friction curve, corresponding to the aforementioned content.

[0017] In a highly advantageous design of the method according to the invention, once the object is virtually pinched by two fingers, a signal is applied to the operating surface in the form of a significant change in friction or a vibration generated by an actuator on the display area. Once the object's edges are touched by fingers on both sides, the object is virtually pinched, and this state is communicated to the user via additional tactile signals. With the aid of these tactile signals, the user receives the information that "the object located between their two fingers can be manipulated." These tactile signals are generated through significant changes in friction, such as a sudden increase in friction and / or an impulse from the actuator vibration.

[0018] The device of the present invention includes an operable display area configured to perform the aforementioned method. Attached Figure Description

[0019] Other advantageous designs for the method of the invention, and for means or devices preferably housed in a vehicle, for implementing the method, can also be found in the embodiments detailed below with reference to the figures. The described and / or illustrated features may form the subject matter of the invention individually or in any meaningful combination, perhaps independently of the claims, and in particular, may also be the subject matter of one or more separate applications. Identical, similar, and / or functionally identical components are shown herein with the same reference numerals:

[0020] Figure 1 A schematic diagram of an apparatus for performing the method is shown, having an operable display area.

[0021] Figure 2-13 An embodiment of the method of the present invention is shown. Detailed Implementation

[0022] exist Figure 1 The diagram schematically shows a device 1 with an operable display area 3. A person, not shown here, touches the display area 3 with two fingers 4a, 4b, typically the thumb and forefinger, in the rest position 7, so as to operate an object 5 by simultaneously swiping with these two fingers 4a, 4b, i.e., magnifying, for example, along the direction of arrows 9a, 9b.

[0023] Display area 3 is now equipped with a plurality of different actuators 11, several of which are arranged laterally around display area 3. Actuators 11 can be located laterally above, below, to the left, or to the right of display area 3 as shown. They can also be designed as strips and located beside or below display area 3. A matrix arrangement of actuators 11 in the region of display area 3, or an arrangement on only one or both sides, is also conceivable. Actuators 11 are adapted to generate vibrations on the surface of display area 3. It can be, for example, a piezoelectric actuator, but can also be an electrostatic and / or capacitive electrode or actuator. Regarding the basic friction acting between fingers 4a, 4b and display area 3 when the actuators 11 are unaffected, this friction can be reduced, for example, by increasing the amplitude and / or frequency of the ultrasonic vibrations generated by the piezoelectric actuator. In another embodiment, an actuator is provided for changing the electrostatic charge of the display area, thus increasing friction due to the increase in electrostatic charge.

[0024] By means of actuator 11, the display area 3 is now positioned to vibrate, for example, such that the coefficient of friction between the display area 3 and the operating fingers 4a, 4b can be changed. Therefore, the friction between the fingers and the display area 3 varies accordingly depending on the position of the fingers 4a, 4b.

[0025] Figure 2 The first variation is shown, where fingers 4a and 4b are in rest position 7 as shown. The magnitude of friction is plotted on the vertical axis 13 of the coordinate system, and the displacement of fingers 4a and 4b along the arrow directions 9a and 9b in the display area 3 is plotted on the horizontal axis 14.

[0026] The displacement-friction curve is represented by graph 15. Friction between display area 3 and fingers 4a and 4b is minimized at rest position 7. From rest position 7, friction increases with a positive gradient in the direction of movement indicated by arrows 9a and 9b. Maximum friction occurs when fingers 9a and 9b touch each other (i.e., have a small distance between them) or have the maximum possible distance between them on display area 3. The user thus receives tactile feedback regarding the scaling ratio when zooming in and out of the object. Similarly, the user can easily find rest position 7, i.e., the initial position, through the tactile feedback generated by the friction curve 15.

[0027] Figure 3 A variation is shown where, starting from position 7, friction increases to a predetermined distance change 17, then decreases; that is, the friction gradient is positive before reaching distance change 17 and then negative. These gradients are chosen such that, in the direction of movement, the positive gradient is steeper than the negative gradient. From another predetermined distance 19, the previous friction curve 15 is repeated or repeated multiple times. This achieves a sawtooth-like friction curve 15, which, for example, provides the user with haptic feedback in the form of repetitive stutters when zooming in or out of a window or when zooming in on an object such as a map. In one modified version, the positive and negative gradients can have slope values ​​of the same magnitude.

[0028] Figure 4 This shows the state of fingers 4a and 4b relative to their resting position, such as an enlarged window, compared to the previous diagram. Fingers 4a and 4b compared to... Figure 3 It moves in the opposite directions of arrows 9a and 9b. Since the gradient of increased friction is smaller than the gradient of decreased friction in this direction of motion, it is more efficient than... Figure 3 When magnified, the frictional resistance towards the resting position 7 is smaller. Different gradients facilitate finding the location of the initial point 7.

[0029] Figure 5 The image shows the state of a window, for example, reduced in size, relative to its resting position, indicated by fingers 4a and 4b. Fingers 4a and 4b, moving in the direction of arrows 9a and 9b, move away from the resting position 7. The friction curve 15 is further shaped such that, after resting, friction increases with a first gradient and then decreases with a gentler gradient compared to the first gradient. Similar to... Figure 3 The friction increases and decreases periodically, which causes a feeling of sticking at the user's fingertips.

[0030] Compared to Figure 5 As shown, fingers 4a and 4b are in Figure 6The fingers move in opposite directions 9a and 9b on display area 3, meaning the window is first zoomed out and then zoomed out again. Because the increasing friction gradient in the movement directions 9a and 9b is now gentler than the decreasing friction gradient, the fingers can easily move to rest position 7. In rest position 7, as the fingers 4a and 4b continue to move, the display area 3 switches to the display area 3. Figure 3 The friction curve 15 shows that the friction gradient is steeper than the friction gradient in the direction of motion. By changing the slope of the resting position 7, the resting position is indicated tactilely and can be easily found by the user.

[0031] Figure 7 The movement of fingers 4a and 4b on display area 3 is shown, wherein the distance between the fingers remains constant. Accompanying this movement is, for example, the displacement or flipping of an object or a portion of the screen. From rest position 7, fingers 4a and 4b move in parallel along the directions of arrows 9a and 9b. Friction curve 15 is set such that the positive and negative friction gradients are, for example, similar to... Figure 3 The alternation of the ground creates a tactile impression that is presented to the user in a series of stuttering motions.

[0032] Figure 8 This illustrates an application scenario involving rotation of a symbolic or virtual switch. The movement of fingers 4a and 4b along the arrow directions 9a and 9b occurs tangentially to the switch element 23, which rotates about the center point 25. The rotation angle is plotted on the horizontal axis 14, and the coefficient of friction is plotted on the vertical axis 13. The friction curve 15 shows that, starting from the rest position 7, as the virtual switch element 23 rotates, the friction increases, providing the user with tactile feedback corresponding to a mechanically rotated switch subjected to a spring force. Friction also increases from the rest position 7 in the rotation direction opposite to the arrow directions 9a and 9b, thus defining the zero position of the switch element 23 at the friction trough.

[0033] Figure 9 and 10 Show Figure 3 and 4 A modification of the implementation shown.

[0034] Compared to Figure 3 ,exist Figure 9 The maximum friction level between fingers 4a, 4b and display area 3 increases with each repetition. Friction curve 15 is repeated from a predetermined distance 19, wherein, simultaneously, the level of the maximum friction level increases in subsequent portions of friction curve 15. With continued repetition, the maximum friction level is continuously increased to a practically feasible maximum value.

[0035] Additionally, as a supplement, the slopes of the ascending and descending gradients can be increased with each repetition. This increases the maximum force that the user's fingers must overcome to reach the next stuttering level.

[0036] and Figure 4 Correspondingly, Figure 10 The two fingers 4a and 4b, which have left the resting position 7, move back towards the resting position 7 along the arrow directions 9a and 9b. The maximum friction value is reduced in each repetition of a portion of the friction curve 15 to facilitate finding the resting position.

[0037] Figure 11 and 12 Show Figure 5 and 6 A modification of the implementation shown.

[0038] Figure 11 The diagram illustrates the state of a window, for example, in a reduced position, relative to the resting position 7, represented by fingers 4a and 4b. Fingers 4a and 4b, moving in the direction of arrows 9a and 9b, move further away from the resting position 7. The friction curve 15 is designed such that, after resting, the friction increases with a first gradient and then decreases with a gentler gradient compared to the first gradient. Similar to... Figure 3 The friction increase and decrease are repeated periodically, with the maximum friction value increased in each repetition. As an additional supplement, the slopes of the ascending and / or descending gradients can be increased with each repetition.

[0039] Compared to Figure 11 , Figure 12 and Figure 6 Similarly, fingers 4a and 4b are shown retracting towards rest position 7. Likewise, the portion of friction curve 15 containing ascending and descending gradients is repeated, wherein the maximum friction value in this portion is continuously reduced. As a supplement, the portion of friction curve 15 containing ascending and descending gradients becomes flatter as it approaches rest position 7.

[0040] Figure 13 This illustrates another application scenario where the object 27 on the display area 3 is virtually pinched or grasped by the fingers 4a and 4b. The fingers 4a and 4b are placed in the resting position 7, and then moved towards the object 27 on the display area 3 in the directions of arrows 9a and 9b. Here, finger 4a is further away from the center of gravity 29 of the object 27 than finger 4b. From the resting position 7, friction is applied at a predetermined gradient along the directions of arrows 9a and 9b and corresponding to… Figure 1The friction gradient also increases in the opposite direction. The gradient of the friction curve 15 between fingers 4a, 4b and display area 3 is designed such that, when moving towards the center of gravity 29, finger 4b moves more slowly while finger 4a moves more quickly. Therefore, the friction gradient corresponds to the distance from the center of gravity 29; that is, the increase in friction between finger 4a and display area 3 is less than the increase in friction between finger 4b and display area 3. In other words, the distance of fingers 4a, 4b from the center of gravity 29 determines this friction gradient. This achieves automatic alignment of object 27 relative to fingers 4a, 4b, so that the fingers touch the edge of object 27 substantially simultaneously. This object contact is signaled to the user by superimposing a signal 29, which is either a significant change in friction or a vibration generated by an actuator. The superimposed signal 29 can be designed, for example, as a step 31, a pulse 33, or a damped vibration 35.

[0041] While the invention has been shown and explained in detail through preferred embodiments, it is not limited to the disclosed examples, and those skilled in the art can derive other variations without departing from the scope of protection of the invention. Therefore, it is clear that many variations are possible. It is also clear that the exemplified embodiments are merely illustrative in nature and should in no way be construed as limiting, for example, the scope of protection, the possibilities of application, or the configuration of the invention. Rather, the foregoing description and drawings enable those skilled in the art to embody the exemplary embodiments, wherein, knowing the disclosed inventive concept, they can make various changes, for example, regarding the function or arrangement of the various components mentioned in one embodiment, without departing from the scope of protection defined by the claims and their legal equivalents, such as those detailed in the description.

Claims

1. A method for generating tactile feedback on a display area (3) that can be operated by finger movement, wherein, The position of the finger on the display area (3) is sensed, and the coefficient of friction between the finger and the display area (3) is adjusted according to the position. Its characteristics are, The resting position (7) of two fingers (4a, 4b) that simultaneously touch the display area (3) is determined, and the friction between each finger (4a, 4b) and the display area (3) is changed according to the change in distance from the resting position (7). The distance change of the fingers (4a, 4b) that simultaneously touch the display area (3) relative to the resting position (7) is caused by a radially completely opposite movement for pinching the object (27), wherein, under the friction gradient rising from the resting position (7), the friction gradient between the display area (3) and the finger resting closer to the reference point (29) of the object (27) is adjusted to be greater than the friction gradient between the display area and another finger, such that the finger resting closer to the reference point approaches the object (27) more slowly than the other finger.

2. The method according to claim 1, characterized in that, The friction between the fingers (4a, 4b) and the display area (3) increases with the distance from the resting position (7).

3. The method according to claim 1 or 2, characterized in that, As the fingers (4a, 4b) are detected approaching the display area (3), the parameters for determining the friction between each finger (4a, 4b) and the display area (3) are adjusted to initial values.

4. The method according to claim 1 or 2, characterized in that, When each of the fingers (4a, 4b) reaches a predetermined distance change (17) from the resting position (7), the friction gradient is adjusted to be a slope opposite to the slope that was effective before reaching the distance change (17).

5. The method according to claim 1 or 2, characterized in that, Starting from another second distance change (19) above the predetermined value, the friction curve (15) is repeated until the second distance change (19) is reached.

6. The method according to claim 5, characterized in that, With each repetition, the slope of the increased and / or decreased friction gradient changes, and / or with each repetition, the maximum value of the repeated portion of the friction curve (15) changes.

7. The method according to claim 1 or 2, characterized in that, The change in distance of the fingers (4a, 4b) that simultaneously touch the display area (3) relative to the resting position (7) is caused by rotating about the rotation center (25).

8. The method according to claim 1 or 2, characterized in that, The change in distance of the finger (4a, 4b) that simultaneously touches the display area (3) relative to the resting position (7) is caused by a radially completely reversed motion for scaling the object.

9. The method according to claim 1 or 2, characterized in that, Once the object (27) is virtually pinched by the two fingers (4a, 4b), signals in the form of significant frictional changes and / or vibrations generated by the actuator are applied to the display area (3).

10. A vehicle device having a display and operation surface, the device being configured to perform the method according to any one of claims 1 to 9.

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