TECHNICAL DATA FIELD

This application relates generally to haptic stimulations, including haptic stimulations that are applied to users of artificial-reality devices.

BACKGROUND

Some haptic devices (sometimes called “haptic displays”) provide haptic feedback to users by applying forces (e.g., tensional and/or radial forces) to a portion of the user's body (e.g., to an anatomical cross-section of a user's wrist). The perceived haptic feedback (e.g., vibration) changes with the amount of force applied, and also according to the stiffness and mechanical impedance of the tissue site being stimulated. Conventional haptic devices, however, fail to account for variances in stiffness and mechanical impedance in body tissues (i.e., they do not account for variability between users, or even variability within a given user). Because of this, conventional haptic devices cannot optimize the forces applied to users (e.g., haptic feedback applied to a first user may feel weak while haptic feedback of the same force applied to a second user may feel intense and uncomfortable). Moreover, a direct mechanical coupling between a vibrotactile actuator and its housing can cause the entire device (e.g., a wrist-worn band) to vibrate, which may be undesirable in some circumstances. This result is known as parasitic haptic signal leakage, and such leakage can limit the ability of a haptic device to apply localized stimulations to a user's body, which reduces an overall efficiency and satisfaction of the haptic device.

SUMMARY

Accordingly, there is a need for haptic devices and systems that can impart localized, uniform haptic stimulations across users. In this way, users can expect a consistent experience with haptic devices, which will help drive adoption of these devices. The designs discussed herein use the technique of impedance shaping to isolate and/or localize vibrations, and tune vibrations for individual users of artificial-reality devices (e.g., wrist-worn haptic devices). Mechanical impedance shaping (sometimes called z-shaping) is the process of systematically tuning the mechanical impedance of various parts of the actuator-tissue system to maximize transmission of vibrations and displacement in an intended direction. To optimize the haptic throughput for efficiency and consistency systematically (as will be discussed in detail below), various design parameters of the actuator can be tuned (either in the design phase or during use), and various actuators can be used, such as resonant, non-resonant, mechanical, electric, pneumatic, hydraulic, or rheological actuators.

(A1) In accordance with some embodiments, an apparatus is provided that creates haptic stimulations. The apparatus includes a brace with a first portion and a second portion. The apparatus also includes a vibrotactile actuator coupled to the first portion of the brace. The vibrotactile actuator is configured to apply a haptic stimulation to a user. The apparatus also includes a linear actuator coupled to the second portion of the brace. The linear actuator is configured to: (i) obtain a signal generated based on information about the user's body at a target location of the user, and (ii) adjust a tension of the brace according to the signal. Note that the linear actuator and/or the vibrotactile actuator can be swapped (or otherwise modified) for other actuators or mechanisms (e.g., one or more of the structures shown inFIGS. 6A-6G), at least in some embodiments.

(A2) In some embodiments of A1, the apparatus further includes one or more sensors (e.g., sensors224,FIG. 2A) configured to generate the information about the user's body at the target location. The one or more sensors may be coupled to the linear actuator, or some other component of the apparatus, such as the brace or the vibrotactile actuator.

(A3) In some embodiments of A2, a controller is configured to: (i) generate the signal based on the information about the user's body at the target location generated by the one or more sensors, and (ii) provide the signal to the linear actuator. In some embodiments, the controller is part of the apparatus, and the controller is communicatively coupled to the linear actuator (and, potentially, the vibrotactile actuator). The controller may also be communicatively coupled to the one or more sensors.

(A4) In some embodiments of A2, the linear actuator is communicatively coupled to the one or more sensors. The one or more sensors are further configured to generate the signal based on the information about the user's body at the target location. In such embodiments, the linear actuator is configured to obtain the signal from the one or more sensors.

(A5) In some embodiments of A4, the one or more sensors are configured to generate the signal by determining stiffness or mechanical impedance of a tissue site of the user. In some embodiments, the information about the user's body at the target location includes biomechanics of a tissue (e.g., biomechanical stiffness, impedance) of the user's body at the target location.

(A6) In some embodiments of any of A2-A5, adjusting the tension of the brace tunes vibration characteristics of the apparatus by minimizing vibrations transmitted from the vibrotactile actuator to the linear actuator (and other portions of the apparatus as well). In some embodiments, the linear actuator is further configured to tune vibration characteristics of the apparatus by adjusting the tension of the brace.

(A7) In some embodiments of any of A1-A6, the linear actuator is configured to adjust the radius of the brace in order to adjust the tension of the brace.

(A8) In some embodiments of any of A1-A7, the vibrotactile actuator is configured to move in one or more first directions, the linear actuator is configured to move in one or more second directions, and the one or more first directions are different from the one or more second directions (e.g., they are perpendicular to each other).

(A9) In some embodiments of any of A1-A8, the brace is a silicone membrane. In some other embodiments, the brace is a spring.

(A10) In some embodiments of any of A1-A9, the linear actuator adjusts the tension of the brace to (i) account for variations in tissue biomechanics at the target location and (ii) provides a uniform perception of vibration to the user.

(A11) In some embodiments of any of A1-A10, the linear actuator is further configured to account for a squeeze (or a tensioning force) applied when the first user wears the haptic device.

(A12) In some embodiments of any of A1-A11, the apparatus further includes a housing that at least partially houses the vibrotactile actuator, the linear actuator, and the brace.

(A13) In some embodiments of any of A1-A12, the vibrotactile actuator is suspended by the brace.

(A14) In some embodiments of any of A1-A13, the linear actuator is communicatively coupled to a computing device, the linear actuator is configured to obtain the signal from the computing device, and the computing device is configured to: (i) generate the signal based on the information about the user's body at the target location; and (ii) provide the signal to the linear actuator.

(A15) In some embodiments of A14, the vibrotactile actuator is communicatively coupled to the computing device, and the vibrotactile actuator is further configured to: (i) receive vibration parameters from the computing device and (ii) actuate based on the vibration parameters to apply the haptic stimulation to the user. In some other embodiments, the vibrotactile linear actuator is configured to obtain a drive signal from the computing device, and the computing device is configured to: (i) generate the drive signal based on the information about the user's body at the target location and (ii) provide the signal to the vibrotactile actuator.

(A16) In some embodiments of any of A1-A15, the apparatus further includes a material interface configured to be positioned between the vibrotactile actuator and the user's body. The material interface is further configured to transmit vibrations between the vibrotactile actuator and the user's body that match a mechanical impedance of the user's body at the target location of the user. In some embodiments, the material interface is fluidically controlled. In such embodiments, a fluidic state (e.g., hardness, softness) of the material interface is set based on the information about the user's body at the target location of the user. The material interface may be fluidically controlled using pneumatic control, hydraulic control, or rheological control.

(B1) In another aspect, a wearable device is provided that includes a wearable structure to be worn on a portion of a user's body. The wearable device also includes a plurality of haptic assemblies, whereby each haptic assembly is coupled to the wearable structure. Each haptic assembly includes the structure of the apparatus of A1 (and, in some embodiments, A2-A16).

(B2) In some embodiments of B1, the wearable structure is a wrist-worn band that houses the plurality of haptic assemblies.

(B3) In some embodiments of any of B1-B2, each brace is configured to improve power efficiency of the wearable device by generating the localized vibrations.

(B4) In some embodiments of any of B1-B3, a first haptic assembly of the plurality of haptic assemblies is configured according to biomechanics of a tissue of the user at a first target location. A second haptic assembly, distinct from the first haptic assembly, of the plurality of haptic assemblies is configured according to biomechanics of a tissue of the user at a second target location, distinct from the first target location.

(B5) In some embodiments of B4, the first haptic assembly is positioned to be worn near the first target location and the second haptic assembly is positioned to be worn near the second target location.

(B6) In some embodiments of any of B1-B5, the wearable structure is configured to be worn by the user by applying a tensioning force or a squeeze about an anatomical cross-section of the user's body (e.g., a wrist).

(B7) In some embodiments of any of B1-B6, each vibrotactile actuator is communicatively coupled to a computing device. Each vibrotactile actuator is configured to vibrate at a respective frequency in response to receiving one or more signals from the computing device.

(C1) In another aspect, an artificial-reality device is provided that includes a head-mounted display that (i) presents content to a user and (ii) includes an electronic display. The artificial-reality device also includes a computing device that is (i) communicatively coupled to the head-mounted display and (ii) configured to generate and transmit one or more signals that correspond to content displayed on the electronic display. The artificial-reality device also includes a wearable device that is communicatively coupled to the computing device. The wearable device includes (i) a wearable structure to be worn on a portion of the user's and (ii) a plurality of haptic assemblies, each of which is coupled to the wearable structure. Each haptic assembly includes the structure of the apparatus of A1 (and, in some embodiments, A2-A16).

(D1) According to some embodiments, a method is provided for isolating (or localizing) vibrations applied to a user by a haptic device. The haptic device includes: (i) a brace with a first portion and a second portion, (ii) a vibrotactile actuator coupled to the first portion of the brace, and (iii) a linear actuator coupled to the second portion of the brace. The method includes obtaining, by the linear actuator, a signal generated based on information about a user's body at a target location of a user of the haptic device. The method also includes adjusting, by the linear actuator, a tension of the brace according to the signal, thereby tuning vibration characteristics of the haptic device.

(D2) In some embodiments of D1, the information includes biomechanics of a tissue (e.g., biomechanical stiffness, impedance) of the user's body at the target location.

(D3) In some embodiments of any of D1-D2, the haptic device further comprises one or more sensors (e.g., sensors224,FIG. 2A). In such embodiments, the method may further include generating the signal based on data from one or more sensors.

(D4) In some embodiments of D3, the haptic device further includes a controller, and generating the signal is performed by the controller.

(D5) In some embodiments of any of D1-D4, adjusting the tension of the brace includes adjusting a radius of the brace.

(D6) In some embodiments of any of D1-D5, the haptic device further comprises a material interface positioned between the vibrotactile actuator and the user's body. The method further includes adjusting (e.g., by the controller) a fluidic state of the material interface based on the information about the user's body at the target location of the user. In some embodiments, adjusting the fluidic state of the material interface includes signaling a source (e.g., a pneumatic source) to add or remove fluid from the material interface.

(D7) In another aspect, a haptic device (e.g., haptic device220,FIG. 2A) is provided. In some embodiments, the haptic device includes one or more processors, and memory storing one or more programs, which when executed by the one or more processors cause the haptic device to perform the method described in any one of D1-D6.

(D8) In yet another aspect, a haptic device is provided and the haptic device includes means for performing the method described in any one of D1-D6.

(D9) In still another aspect, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium stores executable instructions that, when executed by the haptic device with one or more processors/cores, cause the haptic device to perform the method described in any one of D1-D6.

(E1) According to some embodiments, an apparatus is provided that creates haptic stimulations. The apparatus includes a membrane with a first portion and a second portion and an actuator (e.g., a vibrotactile actuator) coupled to and supported by the first portion of the membrane. The actuator is configured to apply a haptic stimulation to a user of the apparatus at a target location on the user's body, whereby the target location on the user's body has a known impedance. The apparatus also includes a housing that is coupled to the second portion of the membrane and at least partially houses the membrane and the actuator. Furthermore, the membrane is selected according to the known impedance of the target location, such that one or more mechanical properties of the membrane, including an elasticity of the membrane, complement the known impedance of the target location to tune vibration characteristics of the actuator at the target location. Note that in some embodiments, the membrane is a different structure, such as a spring.

(E2) In some embodiments of E1, the apparatus also includes another actuator (e.g., linear actuator302), coupled to the second portion of the membrane, configured to: (i) obtain a signal generated based on information about the user's body at the target location, whereby the information about the user's body at the target location includes the known impedance and (ii) adjust a tension of the membrane according to the signal.

(E3) In some embodiments of E2, the apparatus also includes one or more sensors configured to generate the information about the user's body at the target location.

(E4) In some embodiments of E3, a controller is configured to: (i) generate the signal based on the information about the user's body at the target location generated by the one or more sensors, and (ii) provide the signal to the other actuator.

(E5) In some embodiments of E4, the controller is part of the apparatus, and the controller is communicatively coupled to the other actuator (and, in some embodiments, the actuator).

(E6) In some embodiments of any of E4-E5, the controller is further configured to: (i) generate a drive signal based, at least in part, on the information about the user's body at the target location, and (ii) provide the drive signal to the actuator, which causes the actuator to vibrate according to the drive signal. When the apparatus is worn by the user, the actuator vibrates and applies a first haptic stimulation to the user of the apparatus at the target location on the user's body, according to the drive signal.

(E7) In some embodiments of E6, the controller is in communication with an artificial-reality device, and the drive signal is also based on media presented by the artificial-reality device.

(E8) In some embodiments of any of E4-E7, the actuator vibrates with first parameters, including a frequency and an amplitude, in response to receiving the drive signal from the controller. Moreover, the drive signal defines the frequency and the amplitude. In other words, the drive signal is encoded by the controller to cause the actuator to vibrate in a certain way (i.e., vibrate at the frequency with the amplitude).

(E9) In some embodiments of any of E1-E8, the known impedance includes measurements of tissue biomechanics of the user's body at the target location.

(E10) In some embodiments of any of E1-E9, the apparatus further includes a material interface configured to be positioned between the actuator and the user's body. The material interface is further configured to transmit vibrations between the actuator and the user's body that match a mechanical impedance of the user's body at the target location of the user. In some embodiments, the material interface is fluidically controlled. In such embodiments, a fluidic state (e.g., hardness, softness) of the material interface is set based on the information about the user's body at the target location of the user. The material interface may be fluidically controlled using pneumatic control, hydraulic control, or rheological control.

(E11) In some embodiments, a method for fabricating the haptic device of E1-E10 is provided. The method includes determining information about the user's body at a target location. In some embodiments, the information about the user's body includes the known impedance of the user's body at the target location (e.g., biomechanical stiffness and impedance of the user's tissues). The method further includes selecting a membrane that matches/complements the information about the user's body at the target location. For example, the membrane is selected accordance to the known impedance of the user's body at the target location. The method further includes attaching an actuator to the membrane to form a haptic assembly, and attaching the haptic assembly to a housing, which may be an article worn by a user, such as a watch band.

(F1) In accordance with some embodiments, an apparatus is provided that creates haptic stimulations to a user. The apparatus includes a membrane with a first portion and a second portion. The apparatus also includes means for applying a haptic stimulation to the user. The apparatus also includes means for optimizing a behavior of the means for applying the haptic stimulation to the user. In some embodiments, the means for applying the haptic stimulation to the user includes a first actuator (e.g., actuator306), coupled to the first portion of the membrane, that is configured to vibrate or otherwise oscillate. In some embodiments, the means for optimizing the behavior of the actuator includes a second actuator (e.g., actuator302), coupled to the second portion of the membrane, that is configured to adjust a tension of the membrane according to a control signal (e.g., the structure shown inFIG. 6C). In some embodiments, the second actuator obtains the control signal, which is generated based on information about the user's body at a target location of the user. The means for optimizing the behavior of the first actuator may alternatively include springs of different stiffnesses. Alternatively, the means for optimizing the behavior of the actuator may be part of a housing of the apparatus (e.g., an actuator incorporated into the housing), as shown inFIG. 6A.

In some embodiments, the means for applying the haptic stimulation to the user includes a ferrous core magnetically coupled with a magnetic field generator (which together form a solenoid). In such embodiments, the means for optimizing the behavior of the means for applying the haptic stimulation to the user includes a field-strength adjustment mechanism that is configured to adjust an output of the magnetic field generator. An example of this structure is shown inFIG. 6B.

(F2) In some embodiments of F1, the apparatus further includes one or more sensors (e.g., sensors224,FIG. 2A) configured to generate information about the user's body at the target location. The one or more sensors may be coupled to the means for optimizing the behavior of the means for applying the haptic stimulation to the user, or some other component of the apparatus.

(F3) In some embodiments of any of F1-F2, the apparatus further includes a material interface to be positioned between the means for applying the haptic stimulation to the user and the user's body. The material interface is configured to transmit vibrations between the means for applying the haptic stimulation to the user and the user's body that match a mechanical impedance of the user's body at a target location. In some embodiments, the material interface is fluidically controlled. In such embodiments, a fluidic state (e.g., hardness, softness) of the material interface is set based on the information about the user's body at the target location of the user. The material interface may be fluidically controlled using pneumatic control, hydraulic control, or rheological control. The material interface may be a material that can hold a fluid, such as a sealed bladder or similar structure.

(G1) According to some embodiments, a method is provided for optimizing haptic throughput efficiency and consistency. The method is performed at a haptic device that includes a vibrotactile actuator. The method includes applying a haptic stimulation, using the vibrotactile actuator, to a user of the haptic device at a target location on the user's body. The method also includes concurrently measuring (i) mechanical impedance of the vibrotactile actuator, and (ii) tissue mechanical impedance of the target location. The method also includes tuning vibration output from the vibrotactile actuator based on a relationship between the mechanical impedance of the vibrotactile actuator, the tissue mechanical impedance of the target location, and a perceived vibration at the target location.

(G2) In some embodiments of G1, the haptic device further includes an interface material between the vibrotactile actuator and a tissue at the target location, and the method further includes tuning the interface material between the vibrotactile actuator and the tissue for maximum transmission of the haptic stimulation.

(G3) In some embodiments of any of G1-G2, the vibrotactile actuator is coupled to a housing, and the method further includes tuning mechanical coupling between the vibrotactile actuator and the housing to prevent parasitic leakage of vibrotactile signal in unintended directions.

(G4) In some embodiments of any of G1-G3, the haptic device further comprises one or more sensors configured to measure the tissue mechanical impedance, and the method further includes: detecting, based on data from the one or more sensors, a change in the tissue mechanical impedance, during a session of use of the haptic device; and, in response to detecting the change in the tissue mechanical impedance, adjusting the vibration output from the vibrotactile actuator based on a degree of the change.

