Display device for enhancing image resolution

Abstract

A display device (1) for a wearable device, in which the display device (1) is arranged to display an image (11) consisting of a plurality of sub-images (12), the display device (1) comprising a micro LED array (2) arranged to display the sub-images (12) sequentially in time, and a shift unit (3) arranged to shift the sub-images (12) from the micro LED array (2) to the sub-images (12). The shift unit (3) is arranged to shift the sub-images (12) relative to each other, where the sub-images (12) consist of sub-pixels (13), each sub-pixel (13) of a sub-image (12) is adjacent to a sub-pixel (13) of a different sub-image (12) in the displayed image (11), and adjacent sub-pixels (13) of the different sub-image (12) represent display pixels (14) of the displayed image (11).

Description

Technical Field

[0001] The invention relates to an optical device, in particular to an optical device for enhancing image resolution. Background Art

[0002] Visual information has been presented on screens since the advent of digital computers and televisions. Over the decades, increases in computing power have led to dramatic increases in resolution. Despite significant efforts to increase resolution to high densities, emitters in display devices still suffer from the disadvantage of not being able to emit light from edge to edge across their surfaces.

[0003] The surface of an emitter can be divided into two surface areas. One surface area emits light, while the other surface area does not emit light, it is dark. The dark surface area is, for example, the space where connectors are placed. The ratio between the surface area that emits light and the total surface area of ​​the emitter is the fill factor. Until today, the fill factor was less than 100%. This means that the emitter surface consists of areas that do not contribute to the emitted light. Light-emitting devices for displays, especially head-mounted displays, require a high fill factor to display high-quality images.

[0004] In addition to ever-increasing resolution, miniaturization is steadily advancing, placing increasingly demanding requirements on the production of each emitter.

[0005] In wearable devices, micro-LED arrays with multiple emitters are used. However, micro-LED arrays have a poor fill factor of 50%-70%, which results in large dark areas between light emitting areas. As a result, the lack of image quality is noticeable, especially when the micro-LED array is close to the viewer's eyes, such as in wearable devices. Since micro-LED arrays are promising candidates for augmented reality applications, avoiding dark areas and improving resolution are particularly important. Summary of the invention

[0006] Among other things, the device is based on the consideration that there is a need for an improved display device, in particular for producing super-resolution images which takes up only a small installation space.

[0007] The display device is arranged to display an image composed of a plurality of sub-images. The display device comprises a micro LED array and a shift unit. The micro LED array is arranged to display the sub-images sequentially in time. The shift unit is arranged to shift the sub-images relative to each other, wherein the sub-images are composed of sub-pixels. Each sub-pixel of a sub-image is adjacent to a sub-pixel of a different sub-image, and the adjacent sub-pixels of the different sub-images represent display pixels of the displayed image.

[0008] In particular, the display device includes a small installation space so as to be installed in a wearable device.

[0009] In particular, the display device comprises a micro-LED array. The micro-LED array consists of a matrix with emitters, wherein the emitters are arranged in rows and columns. Typically, the micro-LED array comprises several thousand rows and columns of emitters, wherein the emitters are arranged along a repeating rectangular pattern. Each emitter is arranged to emit visible light of a determinable color and intensity and can be individually addressed by a control unit.

[0010] In particular, the image displayed by the display device consists of a plurality of sub-images. The display device is arranged to display the image at an image repetition rate. The image repetition rate is typically 60 Hz. The micro-LED array of the display device is arranged to emit sub-images at the sub-image repetition rate. Thus, the micro-LED array displays the sub-images sequentially in time. The sub-image repetition rate is higher than the image repetition rate, typically 2x, 3x or 4x.

[0011] In particular, each emitter of the micro LED array emits light that forms a light beam. The light beam includes information of the sub-pixel. The information includes intensity and color. The shift unit has a refractive index greater than 1.0, typically a refractive index of 1.5. The light beam hits the shift unit at a first optical surface. By passing through the first optical surface, the light beam is refracted. Due to the larger refractive index of the shift unit relative to the surrounding environment, the light beam is refracted toward the surface normal of the first optical surface. The light beam passes through the shift unit through the second optical surface of the shift unit. The second optical surface refracts the light away from the surface normal of the second optical surface, thereby generating a refracted light beam. The refracted light beam is parallel to the incident light beam, which hits the first optical surface. Therefore, the light beam is laterally displaced.

[0012] Each sub-image of the common image is laterally shifted differently by a shifting unit, so that the sub-images are shifted relative to each other. Each sub-image consists of sub-pixels. In the displayed image, each sub-pixel of a sub-image is adjacent to a sub-pixel of a different sub-image, so that adjacent sub-pixels of different sub-images represent display pixels of the displayed image. In other words, the sub-images of the image are shifted relative to each other by fractions of display pixels.

[0013] In particular, each sub-image contains slightly different information from each other. However, in the low-resolution approximation, the information of the sub-images appears to be the same. Therefore, the sum of the sub-images results in a higher-resolution image.

[0014] According to an embodiment of the present invention, a micro LED array includes a plurality of RGB emitters.

[0015] In particular, each RGB emitter is arranged to represent a display pixel of an image by sequentially representing sub-pixels. The shift unit is arranged to shift the sub-pixels relative to each other so as to display the sub-pixels sequentially in time in adjacent areas.

[0016] Each RGB emitter includes at least one micro-LED. Typically, one micro-LED emits red light, green light, or blue light. Typically, one RGB emitter includes 3 micro-LEDs.

[0017] According to an embodiment of the invention, the shift unit comprises a tiltable window element. The light emitted by the micro LED array is transmitted through the tiltable window element. The shift unit is arranged to shift the sub-images relative to each other by tilting the window element to different tilt states, whereby the shift unit has one tilt state for each sub-image.

[0018] In particular, the displacement unit comprises a tiltable window element. The window element may comprise two parallel planar surfaces, wherein one of the two planar surfaces is a first optical surface of the displacement unit and the other of the two planar surfaces is a second optical surface of the displacement unit. The first optical surface and the second optical surface are always parallel to each other in each different tilt state. The first optical surface and the second optical surface are tilted in a fixed relationship to each other into different tilt states.

[0019] In particular, the RGB emitters of the micro-LED array emit a light beam which is transmitted through the tiltable window element. The light beam is laterally shifted by the shift unit. The light beam comprises information of a sub-pixel of an image. In particular, the image consists of a plurality of sub-images. The shift unit is arranged to laterally shift the sub-images. For each sub-image, the lateral shift is different, so that the sub-images are shifted relative to each other. For each lateral shift, the shift unit is in one of the different tilt states, resulting in one tilt state for each sub-image.

[0020] The shift unit is tilted to each tilt state in a time sequence. First, the shift unit is tilted to a first tilt state and a first sub-image is displayed. Then, the shift unit is tilted to a next tilt state and a next sub-image is displayed.

[0021] According to an embodiment of the present invention, the displayed image consists of at least two sub-images. The micro LED array has a fill factor of at most 50% along a first direction, and the shift unit is arranged to shift the sub-image along the first direction. The light beam emitted by the micro LED array propagates in a propagation direction, wherein the first direction is perpendicular to the propagation direction.

[0022] In particular, if the image is shifted in only a single direction, the filling factor can be defined as a length filling factor. Each RGB emitter includes a light emitting part and a non-emitting part. The length filling factor is the ratio between the sum of the lengths of the light emitting parts and the total length of the RGB emitters along this direction. More particularly, along a first direction (perpendicular to the propagation direction of the light beam), the length filling factor is at most 50%.

[0023] In particular, the micro LED array is arranged to emit a light beam, which describes at least two sub-images. The light beam is emitted into a propagation direction.

[0024] By means of the shifting unit, the sub-images of the common image are shifted laterally relative to one another.

[0025] According to an embodiment of the present invention, the displayed image comprises at least three sub-images, preferably at least four sub-images. The surface of the micro LED array has a fill factor of at most 25%, and the shift unit is arranged to shift the sub-images along a first direction and along a second direction perpendicular to the first direction and perpendicular to the propagation direction.

[0026] In particular, if the sub-images are shifted along a first and a second direction, the fill factor is defined as a surface fill factor, wherein the first and the second directions are inclined relative to each other. Each RGB emitter comprises a light emitting part and a non-emitting part. The surface fill factor is the ratio between the surface of the light emitting part and the total surface of the RGB emitter, wherein the total surface comprises the light emitting part and the non-emitting part. In particular, the surface fill factor is at most 25%.

[0027] In particular, at least three sub-images, preferably at least four sub-images are emitted by the micro LED array. The emitted sub-images are shifted by the shift unit. More specifically, when the micro LED array emits three sub-images, the sub-pixels of the images are shifted relative to each other so that the sub-pixels are arranged at the edges of an imaginary triangle. When the micro LED array emits four sub-images, the sub-pixels of the images are shifted relative to each other so that the sub-pixels are arranged at the edges of an imaginary rectangle.

[0028] In particular, four sub-images form an image displayed by the display device.A display pixel comprises four sub-pixels.

[0029] More particularly, the micro LED array may be arranged to emit more than four sub-images.Such a micro LED array is combined with a shift unit having more than four tilt states.

[0030] According to an embodiment of the present invention, each sub-pixel has a first length along the first direction and / or a second length along the second direction. The shift unit is arranged to shift the sub-image along the first direction by at least the first length, and / or

[0031] The shift unit is arranged to shift the sub-image along the second direction by at least an amount of the second length.

[0032] In particular, the shift unit shifts the sub-image transversely to the emitted light beam. The sub-image is shifted in a first direction, a second direction or in both directions (first direction and second direction) by the shift unit. The transverse shift in both directions results in a higher resolution in the first direction and a higher resolution in the second direction.

[0033] Each sub-pixel of the sub-image is arranged so that a first side of the sub-pixel is parallel to a first direction and / or a second side of the sub-pixel is parallel to a second direction. Each sub-pixel has a first length and / or a second length. The first length is along the first direction, and the second length is along the second direction.

[0034] In particular, the shifting unit shifts the light beam in a first direction, wherein the lateral offset is at least the amount of the first length. More particularly, the shifting unit shifts the light beam in a second direction, wherein the lateral offset is at least the amount of the second length. Laterally shifting the light beam with a lateral offset of at least the first length and / or at least the second length, respectively shifting the sub-images, results in a display of the image without overlapping a sub-pixel of one sub-image with a sub-pixel of another sub-image. A greater degree of shifting of the sub-images as the first length or as the second length results in dark areas between sub-pixels of different sub-images. As a result, the brightness of the final image may be reduced. A lower degree of shifting of the sub-images as the first length or as the second length results in an overlap of adjacent sub-pixels. Said overlap may reduce the quality of the final image.

[0035] According to an embodiment of the invention, the window element is arranged to be tilted about a first tilt axis perpendicular to the propagation direction of the light beam.

[0036] In particular, the micro LED array emits a light beam in a propagation direction. The propagation direction is the direction along which the light beam propagates and hits the displacement unit at the first optical surface.

[0037] In particular, the first tilt axis is arranged perpendicular to the propagation direction of the light beam. Different tilt states are achieved by tilting the window element around the first tilt axis. Thus, by tilting the window element around the first tilt axis, different sub-images are shifted to associated tilt states.

[0038] According to an embodiment of the invention, the window element is arranged to tilt about a second tilting axis which is perpendicular to the first tilting axis.

[0039] In particular, the window element is arranged to be tilted about the second tilt axis to different tilt states in order to refract the light beam for displaying different sub-images.

[0040] In particular, the window element is arranged to tilt around a first tilt axis and a second tilt axis. In particular, the second tilt axis is perpendicular to the propagation direction of the light beam. The tilting around the first tilt axis and around the second tilt axis results in a displacement of the sub-image along the first display direction and along the second display direction.

[0041] According to an embodiment of the present invention, each RGB emitter includes a red micro-LED, a green micro-LED and a blue micro-LED. At least two micro-LEDs of each RGB emitter, red, green or blue, are arranged adjacent to each other. The micro-LEDs of the RGB emitters are arranged so that a person using the display device perceives mixed light of the micro-LEDs of the common RGB emitters.

[0042] In particular, the RGB emitter comprises one micro-LED of each color of red, green and blue, so the RGB emitter comprises a red micro-LED, a green micro-LED and a blue micro-LED.At least two micro-LEDs are arranged adjacent to each other.

[0043] In particular, the four micro LEDs form a light emitting area having a square shape, and thus, the light emitting portion of the RGB emitter has a square shape as seen in a top view along the propagation direction.

[0044] According to an embodiment of the present invention, each RGB emitter includes a red micro-LED, a green micro-LED and a blue micro-LED. At least all red micro-LEDs, all green micro-LEDs or all blue micro-LEDs of the micro-LED array are arranged adjacent to each other. For example, the micro-LED array may include different substrates for micro-LEDs of different colors. Therefore, one substrate includes all red, all green or all blue micro-LEDs. The shift unit includes a tiltable window element. The light of all sub-pixels is transmitted through the tiltable window element, and the tiltable window element is continuous and rigid. Therefore, the light emitted by the micro-LEDs from different substrates is transmitted through the common window element.

[0045] In particular, each RGB emitter comprises a red micro-LED, a green micro-LED and a blue micro-LED. All micro-LEDs are arranged to form a row, wherein the micro-LEDs are arranged adjacent to each other. The light emitted by the entire RGB emitter, respectively the light emitted by the micro-LEDs, forms a light beam. By means of a shifting unit, respectively by means of a tiltable window element, the light beam is shifted relative to its propagation direction. The shifting unit shifts the light beam laterally. Thus, the light emitted by each micro-LED is shifted simultaneously by the same amount.

[0046] The light beam comprises sub-images. Each sub-image is composed of sub-pixels. Light from all sub-pixels passes through a tiltable window element.

[0047] In particular, the tiltable window element is continuous and rigid.Thus, the first optical surface and the second optical surface are formed in a one-piece, continuous manner.

[0048] In a preferred embodiment, the displacement unit of the display device comprises at least one actuator, preferably only one actuator.

[0049] As described above, the shift unit is arranged to shift the sub-images relative to each other. The shift unit may comprise a first and a second optical surface, which are movable relative to each other, in particular by tilting the first and the second optical surface relative to each other around a tilt axis, in particular a first or a second tilt axis, which extends substantially perpendicularly to the first and the second optical surface. In this case, preferably the actuator is designed to achieve a tilting movement between the first and the second optical surface. Preferably, the actuator is arranged to tilt the window element so as to achieve a lateral shift as described above, which is a function of the tilt angle of the window element.

[0050] The actuator is preferably designed as a magnetic actuator. According to the present invention, the magnetic actuator is a device that utilizes a magnetic field to generate and transmit force and / or torque in the displacement unit, and preferably includes a coil and a magnet. The coil 31 can be a winding, which is conductive for electric current. When electric current passes through the coil 31, it generates a magnetic field that applies a magnetic force. The intensity of the magnetic field and the magnetic force depends on the amount of current passing through the coil. Preferably, the displacement unit is connected to a control unit, which can be configured to set the current according to the desired tilt angle of the window element. The coil can include a core to enhance the magnetic force and / or torque that may be generated.

[0051] A magnet, preferably a permanent magnet, may be arranged in the vicinity of the coil, in particular within a significant range of the magnetic field that may be applied by the coil. Thus, the magnetic field generated by the coil interacts with the magnet, generating an attractive or repulsive force between them, depending on the polarity of the generated magnetic field and the orientation of the magnet.

[0052] The displacement unit may further comprise a bearing system, which may guide the tilting motion of the window element. This is particularly advantageous, because the relative arrangement between the coil and the magnet need not be so precisely selected, so that the relative displacement between the coil and the magnet is produced only according to the relative orientation of the magnetic field produced by the coil and the magnet. On the contrary, the bearing system may comprise a bearing, by which the tilting motion may be precisely guided, and the relative arrangement between the coil and the magnet may preferably only consider the direction and / or axis of the desired motion. Preferably, the window element may be held by at least one elastic element, such as a spring. This is advantageous, because when the window element tilts, the elastic element may apply a restoring force or torque to the window element, forcing the window element to enter the nominal position. In particular, at least one elastic element is arranged so that the window element can perform a tilting motion around a first tilting axis and / or a second tilting axis.

[0053] It is within the scope of the invention that the coil is stationary relative to the tilting movement of the window element to be produced and the magnet moves with the window element, or vice versa.

[0054] In a preferred embodiment, the shifting unit comprises a frame, by which the window element is held, wherein the frame has a substantially rectangular or square shape with four corners. In addition, the shifting unit comprises two springs, by which the frame is mounted in two corners of its corners, wherein the springs are each connected to the opposite corners of the frame.

[0055] It is within the scope of the invention that the spring is integrally connected to the frame or is designed as a separate component. In particular, the rectangular frame comprises two long sides and two short sides, wherein the spring is connected to the long sides at the respective first or last quarter of the long sides.

[0056] Preferably, the window element comprises a material with a refractive index greater than 1.6. This is particularly advantageous because the achievable lateral offset is also a function of the refractive index. This means that, in the case of a refractive index greater than 1.6, a small tilt can be set, in particular around the first and / or second tilt axis, to achieve the same lateral offset as a window element with a refractive index offset less than 1.6.

[0057] In a preferred embodiment, the micro LED array defines a central axis, the window element is arranged along the central axis, and the width of the window element is selected so that the window element covers an angular range of ±30 degrees relative to the central axis of the micro LED array.

[0058] The above design of the window element is based on the recognition that when the window element covers the above total 60 degree angle range in the untilted state, the desired lateral offset can be generated. Therefore, within the scope of the present invention, as long as the width of the window element covers the above angle range, the micro LED array and the window element can have a distance that can be adjusted as needed.

[0059] In particular, the window element comprises two faces, wherein the two faces are arranged on opposite sides of the window element and are substantially parallel to each other.Therefore, the window element can be a substantially flat optical component, which makes it easy to manufacture and cheap to purchase.

[0060] In principle, the invention is not limited to window elements of a certain thickness. However, studies have shown that it is advantageous if the faces of the window element have a distance between 3 mm and 30 mm. Within the scope of the invention, especially taking into account the tolerances of common manufacturing processes, any distance between the faces can be set to any value within the specified range. Further advantages of the display device and improvements and developments of applications emerge from the following exemplary embodiments shown in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The basic principle of the display device of the present invention is shown.

[0062] Figure 2 A first exemplary embodiment of the present display device having two tilting states of the shift unit is shown.

[0063] Figure 3 A second exemplary embodiment of the present display device is shown, which device has two tilt axes and has three tilt states of the shift unit.

[0064] Figure 4 A second exemplary embodiment of the present display device is shown, which has two tilt axes and has four tilt states of the shift unit.

[0065] Figure 5 A third exemplary embodiment of the present display device is shown having a micro-LED array with 8×8 RGB emitters displaying four sub-images.

[0066] Figure 6 Four sub-images are shown, each with four sub-pixels, which are summed over time.

[0067] Figure 7 A micro-LED array having RGB emitters including micro-LEDs is shown.

[0068] Figure 8 is a schematic diagram of an arrangement of a micro LED array and a window element, which is not tilted according to view a) and which is tilted according to view b).

[0069] Fig. 9 An exemplary design of a displacement unit is shown in a front view a) and a rear view b).

[0070] Fig.10 An exemplary design of a displacement unit is shown in cross section. DETAILED DESCRIPTION

[0071] In the drawings, identical, similar or identically functioning elements are provided with the same reference numerals. Unless the units are explicitly stated, the drawings and the proportions of the elements shown in the drawings relative to one another should not be considered to be to scale. On the contrary, individual elements may be shown with exaggerated dimensions for better illustration and / or better comprehensibility.

[0072] Figure 1The basic principle of the display device 1 of the present invention is shown. The display device 1 comprises a micro LED array 2 and a shift unit 3. The micro LED array 2 is arranged to emit a light beam 20 comprising information of an image 11. The light beam 20 is emitted into a propagation direction. The shift unit 3 is arranged to shift the light beam 20 laterally along the propagation direction. The propagation direction is the direction along which the light beam 20 propagates and hits the shift unit at the first optical surface. Figure 1 , a lateral displacement Δy of the light beam 20 is shown. The lateral displacement Δy depends on the angle θ. The angle θ is the angle of incidence of the light beam 20 hitting the first optical surface of the displacement unit 3. The angle of incidence is defined as the angle between the incident light beam 20 and the surface normal of the first optical surface. The larger the angle θ is to a certain extent, the larger the lateral displacement Δy is.

[0073] Figure 1 The shift unit 3 in the embodiment is a window element 5, which is tiltable. The window element 5 is composed of a refractive index greater than 1.0. Figure 1 In the figure, the refractive index of window element 5 is 1.5. Figure 1 The window element 5 in FIG. 5 is composed of two planar surfaces parallel to each other. A first optical surface of the two planar surfaces is hit by the light beam 20 at an angle θ. When passing through the first optical surface, the light beam 20 is refracted toward the surface normal of the first optical surface, and after passing through the second optical surface of the two planar surfaces, the light beam 20 is refracted away from the surface normal of the second optical surface. The two transitions that cause the refraction of the light beam 20 result in a lateral deviation of the light beam 20.

[0074] Figure 1 The image 11 in FIG. 1 is shown with a lateral offset Δy. For the sake of clarity, the image 11 is also shown at an angle θ=0°. The micro-LED array 2 consists of RGB emitters 4, Figure 1 In the figure, the micro LED array 2 consists of 2×2 RGB emitters 4.

[0075] Each RGB emitter 4 includes an area that emits light and an area that does not emit light. The latter area is, for example, a dark area where a connector is placed. The ratio between the light emitting surface area of ​​the RGB emitter 4 and the total surface area of ​​the RGB emitter 4 is defined as the surface filling factor. Figure 1 The surface fill factor is 25%.

[0076] Figure 2 A first embodiment of the present display device 1 is shown. The micro LED array 2 consists of 2x2 RGB emitters 4 which emit a light beam 20 comprising information of an image 11. The light beam 20 is emitted to impinge on a first optical surface of a displacement unit 3 in a propagation direction. Figure 2The displacement unit 3 in the embodiment is a window element having two parallel planar surfaces, namely a first optical surface and a second optical surface, which refracts the light beam 20 so that the light beam 20 is displaced laterally.

[0077] The displacement unit 3 is tiltable around a first tilt axis 15. The first tilt axis 15 is arranged perpendicular to the propagation direction. The displacement unit 3 is tiltable around the first tilt axis 15 into different tilt states. Figure 2 Two tilting states are shown in . In each tilting state, the light beam 20 is displaced laterally. For each tilting state of the displacement unit 3, the lateral displacement is different.

[0078] The image 11 displayed by the display device 1 is composed of a plurality of sub-images 12. Each sub-image 12 is associated with a tilt state of the shift unit 3. Figure 2 , two tilt states are shown that result in displaying two sub-images 12. The two displayed sub-images 12 resulting from the two tilt states are spaced apart by a length equal to the first side of the light emitting portion of the RGB emitter 4. The first side of the light emitting portion of the RGB emitter 4 is parallel to the direction in which the light beam 20 is laterally displaced.

[0079] The shift unit 3 is tilted to each tilt state in a time sequence. First, the shift unit 3 is tilted to the first tilt state, and the first sub-image 12 is displayed. Then, the shift unit 3 is tilted to the second tilt state, and the second sub-image 12 is displayed. Figure 2 In the embodiment, the light beam 20 carries the same information in both tilt states, resulting in two sub-images 12 with the same information corresponding to each sub-pixel 13.

[0080] Figure 3 A second embodiment of the present display device 1 is shown. Figure 3 The display device 1 in the embodiment includes a micro LED array device having 2×2 RGB emitters 4, and a shifting unit 3 for shifting a light beam 20 emitted by the micro LED array 2. Figure 2 Compared with the first embodiment, Figure 3 The display device 1 of the second embodiment of the present invention comprises a second tilt axis 16. The second tilt axis 16 is arranged perpendicular to the first tilt axis 15 and perpendicular to the propagation direction. The shift unit 3 can be tilted to different tilt states around the first tilt axis 15 and can also be tilted to different tilt states around the second tilt axis 16. The two tilt states around the first tilt axis 15 are as follows: Figure 3. In each tilt state, the light beam 20 is displaced laterally. The lateral displacement is different for each tilt state of the displacement unit 3. The third tilt state, i.e. the tilt state about the second tilt axis 16, is indicated only by an additional arrow. Each tilt state results in a different shift of the light beam 20. Whereas the tilt about the first tilt axis 15 results in a shift of the light beam 20 along a first direction, the tilt about the second tilt axis 16 results in a shift of the light beam 20 along a second direction which is perpendicular to the first direction and perpendicular to the propagation direction of the light beam 20.

[0081] Figure 3 The shift unit 3 in FIG. 1 is tilted to three different tilt states, generating three different sub-images 12. The shift unit 3 is tilted to each tilt state in a time sequence. First, the shift unit 3 is tilted to the first tilt state, and the first sub-image 12 is displayed. Second, the shift unit 3 is tilted to the second tilt state, and the second sub-image 12 is displayed. Third, the shift unit 3 is tilted to the first tilt state, and the third sub-image 12 is displayed. Figure 3 In each tilt state, the light beam 20 carries different information, resulting in different information in the three sub-images 12. Therefore, the sub-pixel 13 of one sub-image 12 carries different information from the sub-pixel 13 of another sub-image 12, such as Figure 3 Indicated by the different colors of the sub-pixels 13.

[0082] Figure 4 Shows Figure 3 A second embodiment of the present display device 1. The light beam 20 is emitted by the micro LED array 2 and is shifted by the shift unit 3 transversely to the propagation direction of the light beam 20. The display device 1 comprises a first tilt axis 15 and a second tilt axis 16, each of which is perpendicular to the propagation direction. The first tilt axis 15 and the second tilt axis 16 are perpendicular to each other.

[0083] exist Figure 4 In the embodiment, the displacement unit 3 is tilted in four different tilting states. In two of the four tilting states, the displacement unit 3 is tilted around the first tilting axis 15, and in the other two of the four tilting states, the displacement unit 3 is tilted around the second tilting axis 16. Figure 4 In FIG. 1 , only two tilt states about the first tilt axis 15 are shown, the other two tilt states being indicated by corresponding arrows of the associated refracted light beams 20 .

[0084] Each tilt state results in a different sub-image 12. The sub-image 12 is composed of sub-pixels 13. In the displayed image 11, each sub-pixel 13 of one of the four sub-images 12 is adjacent to a sub-pixel 13 of a different sub-image 12 of the four sub-images 12. The adjacent sub-pixels 13 of the different sub-images 12 represent display pixels 14 of the displayed image 11. Figure 4 In the embodiment, each sub-pixel 13 has a square shape, and the display pixel 14 is also composed of four sub-pixels 13 to form a square shape.

[0085] Each sub-image 12 carries different information about the other sub-image 12, and therefore the sub-pixels 13 also form a display pixel 14 composed of different information. However, in a low-resolution approximation, the information of the sub-pixels 13 in the display pixel 14 is the same. This slight variation of the information in the sub-pixels 13 of the display pixel 14 results in a higher resolution of the displayed image 11.

[0086] exist Figure 5 , a micro LED array 2 of a third embodiment of the present display device 1 is shown. Figure 5 The micro LED array 2 in FIG. 1 is composed of 8×8 RGB emitters 4. The RGB emitters 4 are arranged to display an image 11 having a size of 8×8 display pixels 14. The image 11 is composed of a plurality of sub-images 12. Figure 5 Four such sub-images are shown in . Each sub-image 12 is composed of sub-pixels 13 . Figure 5 Each sub-image 12 in has a size of 8×8 sub-pixels 13. The temporal summation of the sub-images 12 produces the displayed image 11. Thus, one sub-pixel 13 of the first sub-image 12, together with one sub-pixel 13 of the second sub-image 12, with one sub-pixel 13 of the third sub-image 12, and with one sub-pixel 13 of the fourth sub-image 12, form a display pixel 14. Thus, respectively, every two sub-pixels 13 are arranged adjacent to each other.

[0087] exist Figure 6 , four sub-images 12 are shown to produce the displayed image 11. Each sub-image 12 has a size of 2×2 sub-pixels 13. For clarity, each sub-image 12 is shown in front of the micro LED array 2. The lateral shifts of the sub-images 12 are different from each other. The displayed image 11 consists of four display pixels 14. The four sub-images 12 are such that each of the display pixels 14 is the sum of four sub-pixels 13.

[0088] Figure 6 The sub-pixels 13 in the first row of each sub-image 12 carry the same information. The sub-pixels 13 in the second row of each sub-image 12 carry different information. Figure 6In the displayed image 11, the sub-pixels 13 of the following sub-image 12 are visualized in a darker color. The temporal sum of the image 12 is shown in the displayed image 11. While in the first row of the displayed image 11, the display pixels 14 are uniform, the display pixels 14 in the second row of the displayed image 11 have different sections, each with different information corresponding to the information of the relevant sub-image 12. For clarity, overlapping areas are shown in the display pixels 14 so as to visualize the sum of the four. In the present invention, the micro LED array 2 is arranged to display sub-images 12 with different information, resulting in a higher resolution in the displayed image 11.

[0089] exist Figure 7 The micro-LED array 2 is shown in FIG. Four of the RGB emitters 4 are highlighted. Each RGB emitter 4 has a surface fill factor of 25%, so the surface fill factor of the entire micro-LED array 2 is 25%. Figure 7 In FIG. 4 , each RGB emitter 4 comprises four micro-LEDs 6. The micro-LEDs 6 emit different light, red, green or blue. The mixture of the emitted light forms an adjustable color.

[0090] The invention is not limited to the exemplary embodiments based on this description. On the contrary, the invention comprises every novel feature and every combination of features, which in particular includes every combination of features in the claims, even if this feature or this combination itself is not explicitly stated in the claims or the exemplary embodiments.

[0091] Figure 8 In views a) and b) schematic representations of the relative arrangement between micro LED array 6 and window element are shown.

[0092] As can be seen from view a), the orientation of the micro LED array 2 defines a central axis 21, along which the window element 5 is arranged. It can also be seen from view a) that the window element 5 has a substantially planar structure, in which its opposite facing sides are spaced 5 mm apart in a plane-parallel manner. However, typically, the thickness 23 of the window element can be between 3 mm and 30 mm. In addition, the window element 5 and the micro LED array 2 are spaced apart at a distance 24. The distance 24 is selected so that the width 22 of the window element 5 relative to the central axis 21 covers an angular range between -θ and +θ. In the present case, θ is 30°, so that the width 22 of the window element 5 covers an angular range of 60°. In another embodiment, not shown here, the window element 5 may also have a smaller or larger width 22, which is naturally a function of the distance 24, and vice versa, if the window element 5 should cover an angular range of 60°.

[0093] The window element 5 is made of a material with a refractive index higher than 1.6.

[0094] When the window element 5 is tilted, the higher refractive index results in a larger lateral displacement Δy. In addition, studies have shown that the achievable lateral Δy is a function of the thickness 23 and tilt of the window element 5. This relationship is Figure 8 As becomes clear in view b) of FIG. 2 , the lateral displacement Δy is greater because the greater the inclination and the thickness 23 of the window element 5. The inclination axis may be the first inclination axis 15 or the second inclination axis 16, respectively.

[0095] Fig. 9 A displacement unit 3 is shown, which comprises a housing 25 and a frame 26 (see view b)), by which the window element 5 is held. The frame 26 has a substantially rectangular shape, which has two long sides and two short sides and four corners. In addition, the displacement unit comprises two spring elements 27, 28, by means of which the frame 26 is mounted in the displacement unit in the two corners at the last quarter of the long sides. Fig. 9 As shown in the view b), the spring elements 27, 28 are each connected in the opposite corners of the frame. In addition, the displacement unit 3 includes an actuator 29, which is used to tilt the window element 5 in the above-mentioned manner and Fig.10 is shown in detail in Fig. 9 As shown in view a) of FIG. 4 , the displacement unit 3 comprises a control unit 30 which is configured to control the actuator 29 depending on a desired tilting about the first tilting axis 15 or the second tilting axis 16, respectively.

[0096] As mentioned above, Fig.10 The displacement unit 3 is shown in a transverse cross-sectional view. Fig. 9 As already described in , an actuator 29 is provided, by means of which a frame 26 holding a window element (not shown here) can be adjusted about a tilting axis, in particular the first tilting axis 15 and / or the second tilting axis 16 .

[0097] The actuator 29 is designed as a magnetic actuator, which uses a magnetic field to generate and transmit movement within the displacement unit 3, and includes a coil 31 and a magnet 32. The coil 31 is a wound wire, which is conductive to an electric current. When an electric current passes through the coil 31, it generates a magnetic field that exerts a magnetic force (not shown). The strength of the magnetic field and the magnetic force depends on the amount of current passing through the coil 31, which is controlled by the control unit 30. The magnet 32 ​​is a permanent magnet, which is mechanically connected to the frame 26 and is arranged within a significant range of the magnetic field that can be applied by the coil 31. The magnetic field generated by the coil 31 interacts with the magnet 32, generating an attractive or repulsive force. Fig. 9 As described, the movement of the magnet 32 ​​is transmitted to the frame and guided by the spring element.

[0098] Reference numerals list

[0099] 1 Display Device

[0100] 2 Micro LED Array

[0101] 3 Shift unit

[0102] 4 RGB emitters / each RGB emitter

[0103] 5 Window components

[0104] 6. Micro LED

[0105] 11 Images

[0106] 12 sub-images / each sub-image

[0107] 13 sub-pixels / each sub-pixel

[0108] 14 display pixels

[0109] 15 First tilt axis

[0110] 16 Second tilt axis

[0111] 20 Beam

[0112] 21 Center axis

[0113] 22 Width of the widget

[0114] 23 Thickness of window element

[0115] 24 Distance between micro LED array and window element

[0116] 25 Shell

[0117] 26 Frame

[0118] 27 Spring element

[0119] 28 Spring element

[0120] 29 Actuator

[0121] 30 Control unit

[0122] 31 Coil

[0123] 32 Magnet

Claims

1. A display device (1) for a wearable device, wherein: The display device (1) is arranged to display an image (11) composed of a plurality of sub-images (12), the display device (1) comprising a micro LED array (2) and a shift unit (3), the micro LED array (2) being arranged to display the sub-images (12) sequentially in time, the shift unit (3) being arranged to shift the sub-images (12) relative to each other, wherein the sub-images (12) are composed of sub-pixels (13), each sub-pixel (13) of the sub-image (12) being adjacent to a sub-pixel (13) of a different sub-image (12) in the displayed image (11), and adjacent sub-pixels (13) of different sub-images (12) representing display pixels (14) of the displayed image (11).

2. The display device (1) according to claim 1, wherein: The micro LED array (2) comprises a plurality of RGB emitters (4).

3. The display device (1) according to claim 1 or 2, wherein: The shift unit (3) comprises a tiltable window element (5), through which light emitted by the micro LED array (2) is transmitted, and the shift unit (3) is arranged to shift the sub-images (12) relative to each other by tilting the window element (5) to different tilt states, whereby the shift unit (3) has one tilt state for each sub-image (12).

4. The display device (1) according to any one of the preceding claims, wherein: The displayed image (11) consists of at least two sub-images (12), the micro LED array (2) has a filling factor of at most 50% along a first direction, and the shift unit (3) is arranged to shift the sub-image (12) along the first direction, and the light beam (20) emitted by the micro LED array (2) propagates along a propagation direction, and the first direction is perpendicular to the propagation direction.

5. The display device (1) according to any one of the preceding claims, wherein: The displayed image (11) consists of at least three sub-images (12), preferably at least four sub-images (12), the surface of the micro LED array (2) has a filling factor of at most 25%, and the shifting unit (3) is arranged to shift the sub-images (12) along the first direction and a second direction, the second direction being perpendicular to the first direction and perpendicular to the propagation direction.

6. The display device (1) according to one of the preceding claims, wherein: Each sub-pixel (13) has a first length along the first direction and / or a second length along the second direction, wherein: The shift unit (3) is arranged to shift the sub-image (12) along the first direction by at least the first length, and / or wherein the shift unit (3) is arranged to shift the sub-image (12) along the second direction by at least the second length.

7. The display device (1) according to any one of claims 1 to 4, wherein: The window element (5) is arranged to be tilted about a first tilt axis (15) perpendicular to the propagation direction.

8. The display device (1) according to claim 7, wherein: The window element (5) is arranged to be tilted about a second tilting axis (16) which is perpendicular to the first tilting axis (15).

9. The display device (1) according to any one of the preceding claims, wherein: Each RGB emitter (4) comprises a red micro-LED (6), a green micro-LED (6) and a blue micro-LED (6), and wherein at least two of the red, green or blue micro-LEDs (6) of each RGB emitter (4) are arranged adjacent to each other.

10. The display device (1) according to any one of claims 1 to 9, wherein: Each RGB emitter (4) comprises a red micro-LED (6), a green micro-LED (6) and a blue micro-LED (6), wherein at least all the red micro-LEDs (6), all the green micro-LEDs (6) or all the blue micro-LEDs (6) of the micro-LED array (2) are arranged adjacent to each other, and the shift unit (3) comprises a tiltable window element (5), wherein light of all sub-pixels (13) is transmitted through the tiltable window element (5), and the tiltable window element (5) is continuous and rigid.

11. The display device (1) according to any one of the preceding claims, wherein: The displacement unit (3) comprises one actuator (29) or exactly one actuator (29).

12. The display device (1) according to at least claim 3, wherein: The window element (5) comprises a material having a refractive index greater than 1.

6.

13. The display device (1) according to at least claim 3, wherein: The micro LED array (2) defines a central axis (21), the window element (5) is arranged along the central axis 21), and the width of the window element (5) is selected so that the window element (5) covers an angular range of ±30 degrees relative to the central axis (21) of the micro LED array (2).

14. The display device (1) according to at least claim 3, wherein: The window element (5) comprises two faces, wherein the two faces are on opposite sides of the arranged window element (5) and are substantially parallel to each other.

15. The display device (1) according to claim 14, wherein: The two faces are spaced apart from each other by at least 3 mm and at most 30 mm.

16. The display device (1) according to at least claim 3, wherein: The displacement unit (3) comprises a frame (26) by which the window element (5) is held, wherein the frame (26) has a substantially rectangular or square shape with four corners, and wherein the displacement unit (3) comprises two springs (27, 28) by which the frame (26) is mounted in two of the corners within the displacement unit (3), wherein the springs (27, 28) are each connected to an opposite corner of the frame (26).

17. The display device (1) according to at least claim 11, wherein: The actuator (29) is designed as a magnetic actuator.

Images