DISPLAY DEVICE

Description

Technical field

[0001] Exemplary embodiments deal with display devices with haptic feedback. In particular, exemplary embodiments deal with display devices and a pixel for a display device. background

[0002] Document US 2016 / 282808 A1 concerns a method and system for a scalable multisensory user experience. A 3D screen is located behind a slotted panel with slits and ultrasonic transducers. Light from the 3D screen passes through the slits in the panel to create a 3D image. The ultrasonic transducers on the front of the panel, i.e., on the opposite side from the 3D screen, generate a directed acoustic field and / or a shaped tactile field.

[0003] Document US 2016 / 147305 A1 concerns a display device comprising a lower substrate, an upper substrate facing the lower substrate, an electro-optically active layer positioned between the lower and upper substrates, and a plurality of membranes arranged on a surface of either the lower or upper substrate. The plurality of membranes are configured to absorb light of a specific wavelength and vibrate to generate ultrasonic waves.

[0004] Document US 2015 / 169136 A1 concerns a display device comprising an array of micromechanical ultrasonic transducers positioned either below, to the side, on top of, or above the back panel of a visual display. The transducers can operate in different frequency ranges to enable gesture recognition, fingerprint sensing, or pen recognition.

[0005] Document US 2016 / 246374 A1 concerns a haptic system that provides tactile feedback above interactive surfaces. Ultrasonic transducers are used to generate an acoustic field that evokes tactile sensations in the air, enabling non-contact feedback. The frequency of the vibrations is dynamically adjusted to ensure optimal haptic perception based on the specific mechanoreceptive properties of human skin.

[0006] Document US 2012 / 082332 A1 relates to a sound-transmitting display device for outputting sound with an object-based position coordinate effect. The device comprises a plurality of pixels, a plurality of holes distributed in an OLED display panel at a specific density to allow sound from a speaker on the back of the OLED display panel to pass through, a driver circuit for controlling the OLED display panel, a protective layer attached to or located near the back of the OLED display panel and consisting of holes that align with the holes in the panel, and a plurality of matrix speakers arranged on the back of the OLED display panel.

[0007] Freely configurable graphical user interfaces for finger operation (also known as "touchscreens") are increasingly replacing conventional controls in everyday devices and instruments (e.g., mobile phones, coffee machines, or cars). These interfaces visually replicate classic sliders and rotary knobs for intuitive operation. However, such purely graphical user interfaces lack haptics and, in particular, tactile feedback. For example, when a virtual button is pressed, a virtual slider is moved to its upper limit, or a virtual rotary knob is turned half a turn, often only an acoustic signal, sometimes perceived as annoying, or a brief vibration is emitted to acknowledge the action.

[0008] To better integrate the human sense of touch into user interfaces, changing positions and shapes of graphically represented objects (e.g., buttons or sliders) should be tracked flexibly. This can be achieved, for example, through mechanical vibrations or waves on the display surface, or by emitting ultrasonic waves into the air. Amplitude fluctuations in displacement or sound pressure can be detected by the human sense of touch. For instance, a modulated resistance can be generated for a human finger, representing the position of a graphically represented (i.e., virtual) switch.

[0009] This feedback via non-optical channels can be particularly important when interaction with the graphical user interface takes place in front of the display or without contact with it. This is the case, for example, with holographic, three-dimensional displays.

[0010] Therefore, there is a need to specify a way to provide tactile feedback. Summary

[0011] This need is satisfied by a display device according to the independent claim. Further embodiments are specified in the dependent claims.

[0012] It should be noted that the claimed invention is subsequently described with reference to the invention described in Fig. 2 The illustrated embodiment of a display device is described. Accordingly, any reference in the following description to a display device according to one of the [references to be added] is to a display device according to any of the [references to be added]. Fig. 1 and Figs. 3 to 6 The illustrated embodiments of a display device are to be understood as an example that merely serves to better understand the claimed invention, without, however, being part of the claimed invention. Character description

[0013] Examples of implementation are explained in more detail below with reference to the accompanying figures. These show: Figures 1 to 3 show exemplary embodiments of a display device; Fig. 4 shows an exemplary embodiment of a pixel for a display device; Fig. 5 shows an exemplary embodiment of a display device comprising the in Fig. 4 displayed pixels; and Fig. 6 shows another embodiment of a display device. Description

[0014] Several embodiments are now described in more detail with reference to the accompanying drawings, in which some of these embodiments are illustrated. For the sake of clarity, the thickness dimensions of lines, layers, and / or regions may be exaggerated in the figures.

[0015] In the following description of the accompanying figures, which merely show some exemplary embodiments, the same reference numerals can denote identical or comparable components. Furthermore, collective reference numerals can be used for components and objects that appear multiple times in an embodiment or in a drawing, but are described jointly with respect to one or more features. Components or objects described with the same or collective reference numerals can be identical with respect to one, several, or all features, such as their dimensions, but may also differ, unless the description explicitly or implicitly indicates otherwise.

[0016] Although embodiments can be modified and altered in various ways, the embodiments shown in the figures are examples and are described in detail herein. It should be clarified, however, that the invention is limited only by the scope of protection of the appended claims, and not by the embodiments as disclosed.

[0017] Identical reference symbols denote identical or similar elements throughout the entire character description.

[0018] Note that an element described as "connected" or "coupled" to another element may be directly connected or coupled to the other element, or there may be intermediate elements.

[0019] The terminology used herein serves only to describe specific embodiments and is not intended to limit the embodiments. As used herein, the singular forms "a," "an," "a," and "the" are to include the plural forms unless the context clearly indicates otherwise. Furthermore, it should be clarified that expressions such as "includes," "containing," "has," and / or "showing," as used herein, indicate the presence of the aforementioned features, integers, steps, processes, elements, and / or components, but do not preclude the presence or addition of one or more features, integers, steps, processes, elements, components, and / or groups thereof.

[0020] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning that a person competent in the field to which the embodiments belong would ascribe to them. Furthermore, it should be clarified that expressions, e.g., those defined in commonly used dictionaries, are to be interpreted as having the meaning consistent with their meaning in the context of the relevant technology, unless expressly defined otherwise herein.

[0021] Fig. 1Figure 1 shows an unclaimed display device 100. The display device 100 comprises an optical structure 110 with a plurality of pixels 111-1, 11-2, ..., 111-n, which are configured to generate an optical image on a front face 112 of the optical structure 110. Furthermore, the display device 100 comprises a plurality of sound transducers 120-1, 120-2, ..., 120-n, which are configured, based on a plurality of control signals 131-1, 131-2, ..., 131-n, to generate a sound field 121 in a space in front of the front face 112 of the optical structure 110 for the purpose of stimulating the sense of touch of a human being. The plurality of sound transducers 120-1, 120-2, ..., 120-n are arranged on a rear face 113 of the optical structure 110. The display device 100 also includes a control circuit 130, which is configured to receive at least one of the majority of control signals 131-1, 131-2, ..., 131-n based on at least one acoustic property of the optical structure 110 to generate.

[0022] In addition to outputting an optical image via the optical structure 110, the display device 100 can also provide tactile feedback on the sound field 121 generated by the plurality of sound transducers 120-1, 120-2, ..., 120-n. By controlling one or more of the plurality of sound transducers 120-1, 120-2, ..., 120-n, taking into account the acoustic properties of the optical structure 110, acoustic distortions or modifications of the sound waves emitted by the plurality of sound transducers 120-1, 120-2, ..., 120-n can be compensated for or at least mitigated by the optical structure 110. In other words, one or more of the majority of control signals 131-1, 131-2, ..., 131-n are pre-distorted based on the acoustic property(ies) of the optical structure 110 in order to compensate for orTo mitigate the acoustic distortion caused by the optical structure 110 of the sound waves emitted by the plurality of sound transducers 120-1, 120-2, ..., 120-n. In this way, the plurality of sound transducers 120-1, 120-2, ..., 120-n can be arranged on the rear side of the optical structure 110 without the sound field 121 generated by the plurality of sound transducers 120-1, 120-2, ..., 120-n in the space in front of the front 112 of the optical structure 110 being negatively affected by the optical structure 110.

[0023] The optical structure 110 can be any type of pixelated structure capable of actively generating an optical image based on one or more control signals. For example, the optical structure could be a light-emitting diode (LED) display. Each pixel can contain one or more inorganic and / or organic LEDs. For instance, each pixel could have at least one LED to emit red, green, or blue light based on a control signal. The optical structure 110 can also include other elements, such as one or more internal control circuits for controlling the individual pixels. The pixels and the other elements of the optical structure 110 can be arranged, for example, on a substrate. The number of pixels can vary depending on the size of the optical structure 110.The resolution of the optical structure 110 varies depending on the desired resolution. For example, the optical structure 110 can provide a resolution of 1280 x 720 pixels, 1920 x 1080 pixels, 4096 x 2160 pixels, or higher.

[0024] The front 112 of the optical structure 110 is the side of the optical structure 110 facing a user of the display device 100. Correspondingly, the back 113 of the optical structure 110 is the side of the optical structure 110 opposite the front 112.

[0025] The majority of sound transducers 120-1, 120-2, ..., 120-n are devices that each convert one (electrical) control signal from the majority of control signals 131-1, 131-2, ..., 131-n into a sound wave or a mechanical wave. For example, a sound pressure level can be generated at a point in space in front of the front face 112 of the optical structure 112. For this purpose, a sound transducer can, for example, be configured to convert the control signal into a sound wave by means of an electromagnetic, an electrodynamic, an electrostatic, a piezoelectric, or a piezoresistive effect and to emit this sound wave.

[0026] The sound waves can be any sound waves that lie outside the range of human hearing. For example, at least one of the majority of sound transducers 120-1, 120-2, ..., 120-n can be configured to emit sound waves with a frequency of at least 25 kHz, 40 kHz, 60 kHz, 100 kHz or more. The ultrasound waves thus generated by the sound transducer are suitable for generating the sound field 121 for stimulating the sense of touch in a human being, since they can be finely modulated locally and lie outside the range of human hearing. As in Fig. 1 As indicated, a person can, for example, perceive tactile feedback by placing one or more fingers into the sound field 121, thereby stimulating their sense of touch. The sound field 121 is the space in front of the front surface 112, in which the sound waves from the majority of sound transducers 120-1, 120-2, ..., 120-n propagate and superimpose (constructively and destructively).

[0027] To enable the display device 100 to be used in compact devices (e.g., mobile phones, laptop computers, or tablet computers), the individual components of the display device 100 should require as little installation space as possible. Accordingly, at least one of the majority of the transducers 120-1, 120-2, ..., 120-n can be designed as a MEMS (MicroElectroMechanical System) transducer. For example, the MEMS transducer can be made of a semiconductor material (e.g., silicon).

[0028] The majority of transducers 120-1, 120-2, ..., 120-n can be distributed across the rear surface 113 of the optical device 110. For example, the majority of transducers 120-1, 120-2, ..., 120-n can be arranged in a two-dimensional configuration on the rear surface 113 of the optical device 110. In some embodiments, the majority of transducers 120-1, 120-2, ..., 120-n can be arranged, for example, in a matrix on the rear surface 113 of the optical structure 110. In other words, the majority of transducers 120-1, 120-2, ..., 120-n can be arranged in rows and columns.

[0029] The control circuit 130 can include a processor, a computer processor (CPU = Central Processing Unit), a graphics processing unit (GPU), a computer, a computer system, an application-specific integrated circuit (ASIC), an integrated circuit (IC), a system-on-a-chip (SoC), a programmable logic element, or a field-programmable gate array with a microprocessor (FPGA) on which software for controlling the plurality of transducers 120-1, 120-2, ..., 120-n runs according to the principles described herein. Furthermore, the control circuit 130 can include one or more memories in which, for example, software for controlling the plurality of transducers 120-1, 120-2, ..., 120-n or other data can be stored.As already indicated above, the control circuit can receive or generate a plurality of control signals for the plurality of transducers 120-1, 120-2, ..., 120-n and subsequently modify them to generate the plurality of drive signals 131-1, 131-2, ..., 131-n. In other words, the control circuit 130 can be configured to pre-distort a plurality of control signals for the plurality of transducers 120-1, 120-2, ..., 120-n based on at least one acoustic property of the optical structure 110 in order to generate the plurality of drive signals 131-1, 131-2, ..., 131-n. The pre-distortion can be performed digitally or analogously.

[0030] At least one acoustic property of the optical structure 110 is a property of the optical structure 110 that describes its interaction with sound waves. For example, at least one acoustic property of the optical structure 110 could be its acoustic transparency. Acoustic transparency describes the degree of permeability of the optical structure to sound waves. At a point of high acoustic transparency, a sound wave can penetrate the optical structure 110 without or without significant distortion, whereas at a point of low acoustic transparency, the optical structure 110 may distort the sound wave significantly or even be impenetrable to it.

[0031] The optical image generated on the front face 112 of the optical structure 110 can be a still image or a single image from a sequence of images (e.g. a video).

[0032] The sound field 121 can be assigned to an object in the optical image generated on the front face 112 of the optical structure 110. In principle, the object can be any object that can be represented in an optical image. For example, the object could be a switch, button, slider, or rotary control depicted in the optical image.

[0033] Accordingly, the control circuit 130 can be configured to generate the plurality of control signals 131-1, 131-2, ..., 131-n based on the state of the object in the optical image. The sound field 121 can be adapted to the state of the object in the optical image. For example, if the object in the optical image moves in a plane parallel to the front face 112 of the optical structure 110, the control circuit 130 can generate the plurality of control signals 131-1, 131-2, ..., 131-n such that the sound field 121 generated by the plurality of sound transducers 120-1, 120-2, ..., 120-n also simulates movement in a plane parallel to the front face 112 of the optical structure 110. For example, the position of a focal point 122 of the sound field 121 can be set depending on the position of the object in the optical image by corresponding control signals 131-1, 131-2, ..., 131-n of the control circuit 130.The focal point 122 is the point in the sound field 121 where at least some of the sound waves emitted by the majority of sound transducers 120-1, 120-2, ..., 120-n overlap, such that the resulting sound pressure, or a variation thereof, at this point is sufficient to selectively stimulate the sense of touch in a human being. One or more focal points can be assigned to a single object. Accordingly, multiple focal points can also be assigned to multiple objects in the optical image.

[0034] If, for example, the object is a virtual button displayed in the optical image that has been pressed by user input, this can be indicated to the user tactilely by, for example, a change in the vertical distance between the focal point 122 of the sound field 121 and the front surface 112 of the optical structure 110. Depending on the vertical distance between the focal point 122 of the sound field 121 and the front surface 112 of the optical structure 110, the user can thus determine whether the virtual button has been pressed or not.

[0035] Accordingly, in the case of a virtual rotary control displayed in the optical image, the focal point 122 of the sound field 121 can follow the rotational movement (i.e., the focal point also rotates). When the virtual rotary control reaches its end stop, this can be indicated tactilely to the user by the focal point 122 of the sound field 121 remaining at a position corresponding to the end stop of the rotary control. Additionally, a sound pressure level or a sound pressure variation can be increased upon reaching the end stop to indicate that the end stop has been reached.

[0036] The focal point 122 of the sound field 121 can be formed either close to the front face 112 of the optical structure 110 or at some distance from it. For example, the control circuit 130 can be configured to generate the majority of control signals 131-1, 131-2, ..., 131-n such that the focal point 122 of the sound field 121 has a vertical distance of less than 2 cm, 1 cm, 5 mm or less from the front face 112 of the optical structure 110. Alternatively, the control circuit 130 can be configured to generate the majority of control signals 131-1, 131-2, ..., 131-n such that the focal point 122 of the sound field 121 has a vertical distance of at least 1 cm, 2 cm, 5 cm, 10 cm or more to the front face 112 of the optical structure 110.

[0037] The control circuit 130 can generate one or more of the plurality of control signals 131-1, 131-2, ..., 131-n, also based on at least one acoustic property of a substrate (not shown) arranged on the front face 112 of the optical structure 110. In this way, the acoustic distortion of the sound waves emitted by the plurality of sound transducers 120-1, 120-2, ..., 120-n can also be compensated for by substrates located between the optical structure 110 and the user (e.g., a protective layer of glass, etc.).

[0038] Furthermore, one or more of the plurality of sound transducers 120-1, 120-2, ..., 120-n can also be used to receive acoustic information. For example, sound waves reflected by a user can be detected in order to recognize a user gesture. At least one of the plurality of sound transducers 120-1, 120-2, ..., 120-n can therefore also be configured to provide an output signal based on received sound waves. This output signal can be processed, for example, by the control circuit 130 or another processor circuit. In some embodiments, for example, switching between the generation of pressure fields and the reception of acoustic information by one or more of the plurality of sound transducers 120-1, 120-2, ..., 120-n can be achieved via appropriate control sequences.

[0039] At the in Fig. 1In the display device 100 shown, the majority of the sound transducers 120-1, 120-2, ..., 120-n are arranged on the back of the optical structure 110. Fig. 2 In contrast, a display device 200 is shown in which, according to the invention, a plurality of sound transducers are arranged on the front, i.e. the side facing a user, of an optical structure.

[0040] The display device 200 comprises an optical structure 210 with a plurality of pixels 211-1, 211-2, ..., 211-n, which are configured to generate an optical image on a front surface 212 of the optical structure 210. Furthermore, the display device comprises a plurality of sound transducers 220-1, 220-2, ..., 220-n, which are configured to generate a sound field 221 in a space in front of the front surface 212 of the optical structure for stimulating the sense of touch of a human being. The plurality of sound transducers 220-1, 220-2, ..., 220-n are arranged on the front surface 212 of the optical structure 210 and are optically transparent to light with a wavelength in the range of 380 nm to 750 nm.

[0041] Like the display device 100, the display device 200 enables not only the output of an optical image via the optical structure 210 but also the provision of tactile feedback via the sound field 221 generated by the majority of sound transducers 220-1, 220-2, ..., 220-n.

[0042] The optical transparency of the majority of sound transducers 220-1, 220-2, ..., 220-n for light with wavelengths in the visible range allows the majority of sound transducers 220-1, 220-2, ..., 220-n to be arranged on the front face 212 of the optical structure 210. Distortion of the sound waves emitted by the majority of sound transducers 220-1, 220-2, ..., 220-n by the optical structure 210 can thus be avoided. Accordingly, sound distortion caused by the optical structure 210 does not need to be taken into account when driving the majority of sound transducers 220-1, 220-2, ..., 220-n.

[0043] The optical structure 210 can be essentially identical to that associated with Fig. 1 The discussed optical structure 110 is constructed.

[0044] The majority of transducers 220-1, 220-2, ..., 220-n, like the majority of transducers 120-1, 120-2, ..., 120-n mentioned above, are designed as MEMS transducers.

[0045] Likewise, the majority of sound transducers 220-1, 220-2, ..., 220-n can be configured to emit sound waves with a frequency of at least 25 kHz, 40 kHz, 60 kHz, 100 kHz or more.

[0046] A sound transducer of the plurality of sound transducers 220-1, 220-2, ..., 220-n is optically transparent to light of a certain wavelength if this light can pass through the sound transducer essentially unimpeded. For example, a sound transducer can be considered optically transparent to light of a certain wavelength if it transmits at least 40%, 50%, 60%, or 70% of the incident light of that wavelength.

[0047] To be optically transparent to light in the range of 380 nm to 750 nm, a transducer of most 220-1, 220-2, ..., 220-n transducers, for example, can have a structured glass substrate (e.g., made of borosilicate glass) with one or more electrodes made of indium tin oxide (ITO). The transducer can also have a diaphragm made of silicon nitride (SiN) or ITO. It goes without saying, however, that the aforementioned materials are merely examples and other optically transparent materials can also be used.

[0048] As already described for the display device 100, the sound field 221 can be associated with an object in the optical image generated on the front face 212 of the optical structure 210. Accordingly, the display device 200 can have a control circuit (not shown) configured to generate a plurality of control signals based on the state of the object in the optical image. In this way, the sound field 221 can be adapted to the state of the object in the optical image.

[0049] The focal point 222 of the sound field 221 can be located either close to or at some distance from the front face 212 of the optical structure 210. For example, the control circuit of the display device 200 can be configured to generate the majority of control signals such that the focal point 222 of the sound field 221 has a vertical distance of less than 2 cm, 1 cm, 5 mm, or less from the front face 212 of the optical structure 210. Alternatively, the control circuit can be configured to generate the majority of control signals such that the focal point 222 of the sound field 221 has a vertical distance of at least 1 cm, 2 cm, 5 cm, 10 cm, or more from the front face 212 of the optical structure 210.

[0050] According to the invention, the majority of sound transducers 220-1, 220-2, ..., 220-n are covered by a substrate (not shown), i.e., the majority of sound transducers 220-1, 220-2, ..., 220-n are arranged between a substrate and the optical structure 210.

[0051] The substrate can, for example, be a protective layer. Accordingly, the control circuit is configured according to the invention to generate one or more of the plurality of control signals based on at least one acoustic property of the substrate. In this way, the acoustic distortion of the sound waves emitted by the plurality of transducers 220-1, 220-2, ..., 220-n can also be compensated for by substrates located between the plurality of transducers 220-1, 220-2, ..., 220-n and the user.

[0052] At least one of the majority of sound transducers 220-1, 220-2, ..., 220-n can, as described above in connection with the majority of sound transducers 120-1, 120-2, ..., 120-n of the display device 100, further be configured to provide an output signal based on received sound waves.

[0053] In the two display devices 100 and 200, sound transducers were externally mounted on an optical structure. In an unclaimed example, however, the optical structure itself can also serve as the source of the sound field. For this purpose, in Fig. 3 The display device 300 is shown.

[0054] The display device 300 comprises an optical structure 310 with a plurality of pixels 311-1, 311-2, ..., 311-n, which are configured to generate an optical image on a front surface 312 of the optical structure 310. The plurality of pixels 311-1, 311-2, ..., 311-n are arranged on a support substrate 314 of the optical structure 310. Furthermore, the display device 300 comprises a plurality of electromechanical transducers 320-1, 320-2, ..., 320-n, which are configured, based on a plurality of control signals 331-1, 331-2, ..., 331-n, to mechanically deform at least the carrier substrate 314 in such a way that, through the mechanical deformation of the carrier substrate 314, a sound field 321 is formed in a space in front of the front face 312 of the optical structure 310 to stimulate the sense of touch of a human person.

[0055] Like the display devices mentioned above, the display device 300 can, in addition to outputting an optical image via the optical structure 310, also provide tactile feedback via the sound field 321 generated by the mechanical deformation of the support substrate 314. No external sound transducers are required to generate the sound field, as the optical structure 310 itself serves as the sound source.

[0056] The optical structure 310 can be essentially identical in construction to the optical structures 110 and 210 described above. However, the optical structure additionally includes the support substrate 314.

[0057] The excitation of the optical structure 310 by the plurality of electromechanical transducers 320-1, 320-2, ..., 320-n is in Fig. 3 This is exemplified by the electromechanical transducer 320-n in section A, which shows an enlarged portion of the display device 300. As in Fig. 3As indicated, the majority of electromechanical transducers 320-1, 320-2, ..., 320-n can be arranged on the support substrate 314 of the optical structure 310, i.e. in a rear region of the optical structure 310.

[0058] The electromechanical transducer 320-n is designed to convert electrical energy into mechanical energy. For example, the electromechanical transducer 320-n can perform a mechanical movement or deformation depending on an applied electrical voltage or current. This conversion process can be based, for example, on the piezoelectric effect or a capacitive effect. Accordingly, in some embodiments, the electromechanical transducer 320-n can be a piezoelectric actuator or a capacitive actuator.

[0059] For example, the electromechanical converter 320-n can perform a length change depending on the control signal 331-n, as indicated by the arrow in Fig. 3 As indicated, due to its attachment to the support substrate 314, the change in length of the electromechanical transducer 320-n deforms a portion of the support substrate 314 (e.g., warped as shown in the figure). Fig. 3 (shown). In addition to the support substrate 314, other elements of the optical structure can also be deformed by the electromechanical transducer 320-n. This is shown in Fig. 3 This is indicated by the deformation of pixels 311-n-3, 311-n-2, ..., 311-n. By deformation of at least the support substrate 314 at a corresponding frequency by the electromechanical transducer 320-n, the optical structure 310 can be excited to emit sound waves.

[0060] By stimulating the optical structure 310 at several points by the plurality of electromechanical transducers 320-1, 320-2, ..., 320-n, the optical structure 310 can be stimulated to emit a plurality of sound waves, which superimpose in the space in front of the front 312 of the optical structure 310 and can thus generate a sound field 321 to stimulate the sense of touch of a human person.

[0061] To generate the plurality of control signals 331-1, 331-2, ..., 331-n, the display device 300 can further comprise a control circuit 330. For example, the control circuit 330 can be configured to generate at least one of the plurality of control signals 331-1, 331-2, ..., 331-n based on at least one mechanical property of the optical structure 310. Accordingly, the deformation of the support substrate 314 or of the optical structure 310 can be matched to the optical structure 310 so that distortion of the desired sound field by the optical structure 310 can be avoided. The at least one mechanical property is a property that characterizes the deformability of the optical structure 310.For example, it could be a torsional modulus, an elasticity model, a Poisson's ratio, a bulk modulus, a material or a strain coefficient of the optical structure 310 or a component thereof.

[0062] The majority of electromechanical transducers 320-1, 320-2, ..., 320-n can be configured, based on the majority of control signals 331-1, 331-2, ..., 331-n, to deform at least the support substrate in such a way that the optical structure emits sound waves with a frequency of at least 25 kHz, 40 kHz, 60 kHz, 100 kHz or more into the space in front of the front face 312 of the optical structure 310.

[0063] As already explained for display devices 100 and 200, the sound field 321 in display device 300 can also be assigned to an object in the optical image. Accordingly, the control circuit 330 can be configured to generate the majority of control signals 331-1, 331-2, ..., 331-n based on a state of the object in the optical image. To avoid repetition, please refer to the explanations above.

[0064] The focal point 322 of the sound field 321 can be located either close to or at some distance from the front face 312 of the optical structure 310. For example, the control circuit 330 can be configured to generate the majority of control signals 331-1, 331-2, ..., 331-n such that the focal point 322 of the sound field 321 has a vertical distance of less than 2 cm, 1 cm, 5 mm, or less from the front face 312 of the optical structure 310. Alternatively, the control circuit can be configured to generate the majority of control signals such that the focal point 322 of the sound field 321 has a vertical distance of at least 1 cm, 2 cm, 5 cm, 10 cm, or more from the front face 312 of the optical structure 310.

[0065] The control circuit 330 can also generate one or more of the plurality of control signals 331-1, 331-2, ..., 331-n based on at least one acoustic property of a substrate (not shown) arranged on the front face 312 of the optical structure 310. In this way, the acoustic distortion of the sound waves emitted by the optical structure 310 can also be compensated by substrates located between the optical structure 310 and the user (e.g., a protective layer of glass, etc.). At least one of the plurality of sound transducers 320-1, 320-2, ..., 320-n can, as described above in connection with the plurality of sound transducers 120-1, 120-2, ..., 120-n of the display device 100, also be configured to provide an output signal based on received sound waves.

[0066] In an unclaimed example, the emission of sound waves can also be integrated into the optical structure. This is shown in Fig. 4 Figure 400 is shown as a display device. The Pixel 400 comprises a first subpixel 410, which is configured to emit red light 412 based on a first control signal 411. The Pixel 400 also comprises a second subpixel 420, which is configured to emit blue light 422 based on a second control signal 421. Furthermore, the Pixel 400 comprises a third subpixel 430, which is configured to emit green light 432 based on a third control signal 431. The Pixel 400 also includes a sound transducer 440, which is configured to emit sound waves based on a fourth control signal 441.

[0067] The Pixel 400 enables the display of both optical information about the emission of red, green, and blue light 412, 422, 432 and tactile information about the emission of sound waves 442. Integrating the wave transducer 440 into the Pixel 400 simplifies the overall design of display devices with tactile feedback.

[0068] Subpixels 410, 420, and 430 can each contain a light-emitting diode (LED) emitting red, blue, and green light, respectively. Alternatively, subpixels 410, 420, and 430 can each contain an LED emitting blue light, with subpixels 410 and 430 additionally including a conversion element to convert the blue LED light into red and green light, respectively. The LEDs can be made of, for example, organic and / or inorganic semiconducting materials. By additively mixing the red, green, and blue light (412, 422, 432), pixel 400 can represent a variety of color values ​​(i.e., mixed colors).

[0069] In some embodiments, the transducer 440 can again be a MEMS transducer. The transducer 440 can be configured to emit sound waves with a frequency of at least 25 kHz, 40 kHz, 60 kHz, 100 kHz or more.

[0070] The sound transducer 440 can, as described above in connection with the majority of sound transducers 120-1, 120-2, ..., 120-n of the display device 100, further be configured to provide an output signal based on received sound waves.

[0071] An implementation of the Pixel 400 in a Display Device 500 is in Fig. 5 shown. The display device 500 comprises a majority of the elements associated with Fig. 4The described pixels 400-1, 400-2, ..., 400-n are configured to generate an optical image on a front face 512 of the display device 500. The display device 500 further comprises a control circuit 530, which is configured to generate a plurality of fourth control signals 441-1, 441-2, ..., 441-n for the plurality of pixels 400-1, 400-2, ..., 400-n, such that the sound transducers of the plurality of pixels 400-1, 400-2, ..., 400-n in a space in front of the front face 512 of the display device 500 generate a sound field 521 to stimulate the sense of touch of a human being.

[0072] The display device 500 can, in addition to outputting an optical image, also provide tactile feedback via the sound field 521 generated by the sound transducers of the majority of pixels 400-1, 400-2, ..., 400-n.

[0073] As already explained above with regard to the display devices 100, 200 and 300, the sound field 521 or a focal point 522 of the sound field 521 can be assigned to an object in the optical image. The control circuit 530 can therefore be configured to generate the majority of fourth control signals 441-1, 441-2, ..., 441-n based on a state of the object in the optical image.

[0074] In some embodiments, the majority of pixels 400-1, 400-2, ..., 400-n can be covered by a substrate (not shown). In other words, in some embodiments, the majority of pixels 400-1, 400-2, ..., 400-n can radiate sound waves through a substrate into the space in front of the display device 500. The substrate can, for example, be a protective layer. Accordingly, the control circuit 530 can also generate one or more of the majority of fourth control signals 441-1, 441-2, ..., 441-n based on at least one acoustic property of the substrate. In this way, the acoustic distortion of the sound waves emitted by the majority of pixels 400-1, 400-2, ..., 400-n can also be compensated by substrates located between the majority of pixels 400-1, 400-2, ..., 400-n and the user.

[0075] The focal point 522 of the sound field 521 can be located either close to or at some distance from the front face 512 of the display device 500. For example, the control circuit 530 can be configured to generate the majority of fourth control signals 441-1, 441-2, ..., 441-n such that the focal point 522 of the sound field 521 has a vertical distance of less than 2 cm, 1 cm, 5 mm, or less from the front face 512 of the display device 500. Alternatively, the control circuit can be configured to generate the majority of control signals such that the focal point 522 of the sound field 521 has a vertical distance of at least 1 cm, 2 cm, 5 cm, 10 cm, or more from the front face 512 of the display device 500.

[0076] In conclusion, in Fig. 6Another unclaimed display device 600 is shown. The display device comprises an optical structure 610 with a plurality of pixels 611-1, 611-2, ..., 611-n, which are configured to generate an optical image on a front face 612 of the optical structure 610. At least one of the plurality of pixels 611-1, 611-2, ..., 611-n (for example, pixel 611-n) comprises a first subpixel 640, which is configured to emit red light 642 based on a first control signal 641. The pixel further comprises a second subpixel 650, which is configured to emit blue light 652 based on a second control signal 651. Furthermore, the pixel comprises a third subpixel 660, which is configured to emit green light 662 based on a third control signal 661, and an acoustically transparent area 670. The display device 600 also comprises a plurality of sound transducers 620-1, 620-2, ..., 620-n, which are configured to generate a sound field 621 in a space in front of the front face 612 of the optical structure 610 to stimulate the sense of touch of a human person. One of the majority of sound transducers 620-1, 620-2, ..., 620-n (for example, sound transducer 620-n) is arranged on a rear face 613 of the optical structure 610 such that an area of ​​the sound transducer in which it emits sound waves at least partially covers the acoustically transparent area 670 of the pixel.

[0077] Like the display devices described above, the display device 600 can, in addition to outputting an optical image via the optical structure 610, also provide tactile feedback about the sound field 621 generated by the plurality of sound transducers 620-1, 620-2, ..., 620-n. Distortion of the sound waves emitted by the single sound transducer of the plurality of sound transducers 620-1, 620-2, ..., 620-n by the optical structure 610 can be avoided by positioning the sound transducer on the back 613 of the optical structure, in alignment with the acoustically transparent area 670 of the pixel. Accordingly, sound distortions caused by the optical structure 610 need not be taken into account, or only minimally, when controlling the sound transducer.

[0078] The other sound transducers of the plurality of sound transducers 620-1, 620-2, ..., 620-n can each be arranged on a rear surface 613 of the optical structure 610 such that a respective area of ​​the sound transducers in which they emit sound waves at least partially covers an acoustically transparent area 670 of one of the plurality of pixels 611-1, 611-2, ..., 611-n. Accordingly, distortion of the sound waves emitted by the plurality of sound transducers 620-1, 620-2, ..., 620-n by the optical structure 610 can be avoided.

[0079] The acoustically transparent area 670 of the pixel is an area of ​​the pixel that can be penetrated by a sound wave without significant distortion. For example, the acoustically transparent area 670 can be a cutout (e.g., a hole). If the optical structure 610 includes other elements such as a substrate, then areas of these elements that cover the acoustically transparent area 670 of the pixel can themselves be acoustically transparent. Otherwise, the optical structure 610 can be essentially constructed like the optical structure 110 described above.

[0080] One or more of the majority of transducers 620-1, 620-2, ..., 620-n can in turn be configured as MEMS transducers. Likewise, the majority of transducers 620-1, 620-2, ..., 620-n can be configured to emit sound waves with a frequency of at least 25 kHz, 40 kHz, 60 kHz, 100 kHz or more.

[0081] As already explained in relation to the display devices above, the sound field 621 can be associated with an object in the optical image generated on the front face 612 of the optical structure 610. Accordingly, the display device 600 can have a control circuit (not shown) configured to generate a plurality of control signals for the plurality of sound transducers 620-1, 620-2, ..., 620-n based on the state of the object in the optical image. In this way, the sound field 621 can be adapted to the state of the object in the optical image.

[0082] The focal point 622 of the sound field 621 can be located either close to or at some distance from the front face 612 of the optical structure 610. For example, the control circuit of the display device 600 can be configured to generate the majority of control signals such that the focal point 622 of the sound field 621 has a vertical distance of less than 2 cm, 1 cm, 5 mm, or less from the front face 612 of the optical structure 610. Alternatively, the control circuit can be configured to generate the majority of control signals such that the focal point 622 of the sound field 621 has a vertical distance of at least 1 cm, 2 cm, 5 cm, 10 cm, or more from the front face 612 of the optical structure 610.

[0083] The control circuit of the display device 600 can also generate one or more of the plurality of control signals based on at least one acoustic property of a substrate (not shown) arranged on the front face 612 of the optical structure 610. In this way, the acoustic distortion of the sound waves emitted by the plurality of sound transducers 620-1, 620-2, ..., 620-n can also be compensated for by substrates (e.g., a protective layer of glass, etc.) located between the optical structure 610 and the user.

[0084] At least one of the majority of sound transducers 620-1, 620-2, ..., 620-n can, as described above in connection with the majority of sound transducers 120-1, 120-2, ..., 120-n of the display device 100, further be configured to provide an output signal based on received sound waves.

[0085] Exemplary embodiments of the present disclosure thus relate, among other things, to a stacked or integrated arrangement of optical and acoustic elements. The properties of both elements can be adapted and coordinated with one another. With this arrangement, a spatially and temporally variable pressure field can be generated in front of an active optical display.

[0086] According to an unclaimed example, a two-dimensional array of ultrasonic transducers can be positioned behind an active optical display. The control of the individual ultrasonic transducers can be corrected to suppress distortion in the acoustic field caused by the acoustic properties of the optical display. Likewise, the individual ultrasonic transducers can be adapted to the acoustic properties of the optical display; in particular, the optical display can serve as an acoustic matching layer for the ultrasonic transducers located behind it. For example, the ultrasonic transducers can be configured as an array. The ultrasonic array can also be constructed using microsystems technology methods.

[0087] According to the invention, a two-dimensional arrangement of ultrasound transducers can be positioned in front of an active optical display. The ultrasound transducers are made of optically transparent material.

[0088] Similarly, in an unclaimed example, an active optical display can be used as a sound source. For example, the sound source can be structured behind the optical display using laterally acoustically isolated ultrasonic transducers.

[0089] In this way, a pressure field that varies in time and location in front of the optical display can be used for tactile feedback. Optical and acoustic systems can thus form optimally coordinated units. The flat design also ensures that the thickness of the display is only minimally increased. Furthermore, no space is required to the side of the optical display for ultrasonic transducers.

[0090] The proposed display devices can be used, for example, for mobile devices (e.g., smartphones, laptop computers or tablet computers), the output of computer graphics (e.g., for computer games), or for the control of machines and cooperative robotics.

[0091] Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device can also be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device.

[0092] The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention be limited only by the scope of protection set forth in the following claims and not by the specific details presented herein by way of description and explanation of the embodiments.

Claims

1. A display device (200) comprising: an optical structure (210) having a plurality of pixels (211-1, 211-2, ..., 211-n) configured to form an optical image on a front side (212) of the optical structure (210); a plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) configured to form a sound field (221) in a space in front of the front side (212) of the optical structure (210) for stimulating the tactile sense of a human person, wherein the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) are disposed on the front side (212) of the optical structure (210), wherein the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) are optically transparent to light having a wavelength in the range of 380 nm to 750 nm, wherein the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) are disposed between a substrate and the optical structure (210), and wherein the display device further comprises a control circuit configured to generate at least one of a plurality of drive signals for the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) based on at least one acoustic property of the substrate.

2. The display device of claim 1, wherein at least one of the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) is configured to radiate sound waves having a frequency of at least 25 kHz.

3. The display device of claim 1 or claim 2, wherein the sound field (221) is associated to an object in the optical image.

4. The display device of claim 3, wherein the control circuit is configured to generate the plurality of drive signals for the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) based on a state of the object in the optical image.

5. The display device of claim 4, wherein the control circuit is configured to generate the plurality of drive signals such that a focal point (222) of the sound field (221) has a vertical distance of at least 2 cm to the front side of the optical structure (210).

6. The display device of any of the preceding claims, wherein at least one of the plurality of MEMS sound transducers (220-1, 220-2, ..., 220-n) is further configured to provide an output signal based on received sound waves.

7. The display device of any of the preceding claims, wherein the substrate is a protective layer.