Multi-pixel display devices

Abstract

A multi-pixel display device comprises: an integrated circuit (1); a plurality of light-emitting semiconductor chips (11) arranged on the integrated circuit (1); a display area (37) having a plurality of pixels (40), wherein each of the light-emitting semiconductor chips (11) is assigned to one of the pixels (40); and a light-guiding element (35) arranged between the plurality of light-emitting semiconductor chips (11) and the display area (37) and adapted to guide light from each of the plurality of light-emitting semiconductor chips (11) to the pixel (40) to which it is assigned.

Description

[0001] The invention relates to a multi-pixel display device.

[0002] μLED displays include a large number of light-emitting semiconductor chips for display pixels. Small LEDs are called "micro-LEDs" or "μLEDs". They can be controlled with the aid of pulse width modulation (abbreviated to "PWM"). Of course, the thin-film transistors ("TFTs" in English) used for this purpose can only switch frequencies of up to 1 MHz.

[0003] Therefore, many applications require the use of integrated circuits (abbreviated as "IC"), which are also called "integrated circuits", as drivers instead of the TFTs mentioned above. In order to reduce the cost of the IC, multiple pixels are operated by one IC. Of course, this approach brings the following disadvantages: multiple controlled μLEDs must be mounted on a relatively large carrier surface around the driver IC, which results in higher (cost) costs. In order to contact the IC, many connections and many narrow electrical printed conductors must be provided for the μLED. Document US 9,318,475 discloses such a device, in which many μLEDs with driver ICs are mounted on a circuit board and are conductively connected to the driver IC. One IC can operate 12 pixels with 36 sub-pixels (i.e. μLEDs) and has 64 connection contacts.

[0004] The object is to provide an improved device with a plurality of pixels.

[0005] The object is achieved by a multi-pixel display device having an integrated circuit and a plurality of light-emitting semiconductor chips arranged on the integrated circuit. A display area comprises a plurality of pixels, wherein each light-emitting semiconductor chip is assigned to one of the pixels. A light-guiding element is arranged between the plurality of light-emitting semiconductor chips and the display area and is suitable for guiding the light of each light-emitting semiconductor chip from the plurality of light-emitting semiconductor chips to the pixel assigned thereto.

[0006] An integrated circuit or IC is a semiconductor chip on which a light-emitting semiconductor chip, for example, an LED or μLED, is mounted and is electrically conductively connected to the integrated circuit, so that the integrated circuit has a carrier function in addition to its driver function for the light-emitting semiconductor chip. The light-emitting semiconductor chip can have a housing or be unpackaged for the purpose of a smaller structural size. The light-emitting semiconductor chip is a light source for a pixel in a display area. The light-emitting semiconductor chip for at least two pixels is arranged on the IC. The light is guided from the light-emitting semiconductor chip to the position of the pixel by means of a light-guiding element. In the display area, the pixel extends in the area in which it extends beyond the area in which the light-emitting semiconductor chip is arranged. The display area with the pixel is usually larger than the base surface of the IC with the light-emitting semiconductor chip arranged thereon. In other words, the core idea includes: instead of placing a light-emitting semiconductor chip, for example, a μLED, in each pixel, a light-emitting semiconductor chip for multiple pixels is placed on the driver IC. The IC is a multi-pixel driver IC with a light-emitting semiconductor chip, whose light is optically distributed for the pixel. The light of the light-emitting semiconductor chip can also be guided into the pixel by a light-guiding element, which is referred to as an optical device. The light-guiding element realizes the distribution of light into the pixel. ICs are advantageously as small as possible in order to save costs. However, sufficient space must be provided for the light emitting semiconductor chip.

[0007] The display can be composed of a plurality of multi-pixel display devices each having an IC. A plurality of multi-pixel display devices for a display device can be integrated into one display device. Alternatively, the display device can be composed of a plurality of multi-pixel display device modules each having an IC. In the above-mentioned multi-pixel display device, a relatively small number of pixels (e.g., less than 100) are combined for one driver IC and a large number of such driver ICs are arranged in the display. Compared with the case where a tightly packed μLED array including all pixels of the display is imaged onto a screen by means of an optical device, the distance between the light source and the surface of the display area (similar to the screen on which the image is displayed) is significantly smaller. For this purpose, a large distance between the light source and the display screen will be required. For example, μLEDs for up to 100 pixels are arranged on the IC. In a high-definition display, then, there will be at least 20,000 such ICs in the corresponding multi-pixel display device.

[0008] The multi-pixel display device has a significant reduction in the expenditure on electrical wiring, thereby reducing the requirements and costs of the substrate on which the IC is mounted. A small number of electrical IC contacts is required, which is associated with simple mounting.

[0009] Compared to conventional solutions in which one IC is provided for each light-emitting semiconductor chip, fewer ICs are required and the light-emitting semiconductor chips are not mounted on a substrate. Rather, they can be pre-mounted on the IC in a compact and therefore cost-effective manner and tested.

[0010] By arranging the light directing element below the display area, the risk of ESD damage and mechanical damage to the IC and light emitting semiconductor chips is lower because it is away from the user.

[0011] In one embodiment of a multi-pixel display device, more than one light-emitting semiconductor chip is assigned to a pixel. This can be a group of red, blue and green light-emitting semiconductor chips. The light-guiding element achieves good light mixing in its light-guiding area. Even at a short viewing distance, the red, green and blue sub-pixels cannot be visible individually.

[0012] In one embodiment, the pixel towards which the emitted light is directed is arranged laterally offset on a light emitting semiconductor chip or multiple light emitting semiconductor chips assigned thereto. Since the base area of ​​the display area is larger than the base area of ​​the IC, the pixels are usually arranged opposite to the base area of ​​the IC having the light emitting semiconductor chip.

[0013] In one embodiment, a light guiding element having an upper side and a lower side has a plurality of light guiding structures, each of which has an incoupling region at the lower side and has one of the pixels above the outcoupling region at the upper side. Light propagates along the light guiding structures in the light guiding element from the light emitting semiconductor chip to the pixel. One or more light emitting semiconductor chips assigned to the pixel are arranged adjacent to the incoupling region of the light guiding structure comprising the pixel. A reflector can be arranged on the side of one or more light emitting semiconductor chips in order to guide the laterally emitted light onto the incoupling region.

[0014] The light guiding element, also referred to as an optical device, can be a structured light guide stack in which structured layers of different materials form a light guiding structure by means of a light guiding core material in a cladding material with a preset light path. In other words, a plurality of layers with light guiding areas are provided in the light guiding element. By stacking layers with different light guiding areas, a three-dimensional light path through the layer stack is preset.

[0015] Alternatively, the light guiding element comprises a free beam optical device, wherein the light is guided on the path from the light emitting semiconductor chip to the pixel by optical components integrated in the light guiding element. Such a free beam optical device can have lenses and other optical components. In a free beam optical device, the light guiding structure is a path of the light through the optical device that is predetermined by the optical components. The coupling-in region and the coupling-out region can comprise openings and / or optical elements, for example lenses or collimators.

[0016] In one embodiment, the light guiding element has at least one collimator. The collimator is used to generate light with a focused, in particular approximately parallel, beam path and to enable the focused light to be emitted.

[0017] In one embodiment, the light guiding element has at least one reflector, for example a mirror, for deflecting the light.The optical device can be a free-beam optical device with a planar or curved reflector.

[0018] In one embodiment, the light guiding element has at least one buncher for bunching the light. Such a buncher can include a lens.

[0019] In one embodiment, the light guiding element has at least one optical waveguide. This cable-like optical waveguide or glass fiber allows light to be transmitted along the cable. The cable can be encapsulated with a filling material for protection and mechanical stability. The optical device can be a fiber bundle with or without a fiber coupler coupled into the optical device.

[0020] In one embodiment of the multi-pixel display device, the light-emitting semiconductor chips are arranged on the integrated circuit along one or more circles or along a straight line or in an array. The semiconductor chips can be arranged on the integrated circuit at the edge, centered or distributed on the base surface. For example, one or more rows can be arranged at the edge.

[0021] In one embodiment, the display area has a dark layer, preferably a black layer, in whose recesses or on whose recesses the pixels are arranged. This achieves a better contrast. Compared to pixels with a relatively large black area, a multi-pixel display device can have relatively small light points. Alternatively, the light point can fill the entire pixel because the light is projected onto a spaced-apart screen that serves as a scattering layer. The advantage here is that no screen door effect (English "Screen Door Effect") is produced. In this embodiment, but in an alternative embodiment, the display area has a scattering layer.

[0022] The multi-pixel display device can also include a substrate on which an integrated circuit is arranged and which is electrically conductively connected to contact areas on the substrate. The contact areas are electrically conductively connected to contacts of the IC in order to power and control it. Due to the mounting of the light-emitting semiconductor chip on the IC and the electrical contacts connected thereto, the IC advantageously has external contacts which are only used for current supply and / or voltage supply, data and clock / synchronization. No LED connection is required. The IC can be electrically contacted by wire contacts, planar connections (so-called "Planar Interconnects") or flip-chip mounting and can be electrically connected to the contact areas.

[0023] The multi-pixel display device is explained in more detail below with reference to exemplary embodiments and the associated figures.

[0024] Figure 1 Illustration of the basic idea of ​​a multi-pixel display device.

[0025] Figure 2 and Figure 3 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side and top view.

[0026] Figure 4 and Figure 5 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side cross-sectional and top view.

[0027] Figure 6 and Figure 7 A schematic diagram showing one embodiment of a multi-pixel display device in side and top view.

[0028] Figure 8 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in top view.

[0029] Fig. 9 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side cross-section.

[0030] Fig.10 and Fig.11 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side and top view.

[0031] Fig.12 and Fig.13 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side cross-sectional and top view.

[0032] Fig.14 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side cross-sectional view.

[0033] Fig.15 A schematic diagram of one embodiment of a multi-pixel display device is shown in side cross-sectional view.

[0034] Figures 16 to 20 Embodiments are shown for arranging a light-emitting semiconductor chip on an integrated circuit.

[0035] Fig.21 A schematic diagram of one embodiment of a multi-pixel display device is shown in side cross-sectional view.

[0036] Fig. 22 A schematic diagram of one embodiment of a multi-pixel display device is shown in side cross-sectional view.

[0037] Fig.23 One embodiment of a coupling region is shown in a side cross-sectional view.

[0038] Figure 1 The basic idea of ​​a multi-pixel display device is illustrated in terms of the light paths from two integrated circuits 1 (ICs for short) to the pixels. The IC 1 is a semiconductor chip with electronic circuits applied on a small plate of semiconductor material.

[0039] As the light emitting semiconductor chip 11 ( Figure 1 In an embodiment (not shown in FIG. 1 ), a plurality of μLEDs are arranged on each IC 1, and as indicated by arrows 3, the light of, for example, red, blue and green, of the light-emitting semiconductor chip is guided to pixels 40 adjacent to the IC 1. The pixels 40 are arranged on the opposite side of the base surface of the IC 1. The pixels 40 can have, for example, an area of ​​1×1 mm or 0.1×0.1 mm. The IC 1 can have, for example, a base surface of 0.15×0.3 mm or 0.1×0.1 mm.

[0040] In the following, embodiments of a multi-pixel display device are described, inter alia, based on an intermediate product during manufacture in order to clarify the individual components and their functions.

[0041] Figure 2 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side view. Figure 3 A schematic diagram showing the same intermediate product in top view.

[0042] The multi-pixel display device (and the intermediate product shown) comprises an integrated circuit 1, which is configured as a semiconductor chip; and a substrate 5, which comprises, for example, a printed circuit board (PCB), on the upper side of which a conductive structure 7 is arranged. The conductive structure comprises a further contact area 8 below, which is conductively connected to the IC 1 in order to supply it with power and control it. In addition, additional conductive structures 7 can be provided below the IC 1.

[0043] In this embodiment, six contact areas 8 for accompanying voltages or signals are provided: a first power supply potential VDD1 and a second power supply potential VDD2, a reference potential GND, a serial data input terminal SDI and an output terminal SDO, and a clock signal CLK for synchronizing the data or image refresh rate. For example, a first power supply voltage of 4V can be applied to the LED, which is connected between the first power supply potential VDD1 and the reference potential GND, and a second power supply voltage of 1.8V can be applied to the IC 1, which is connected between the second power supply potential VDD2 and the reference potential.

[0044] IC 1 is mounted on a substrate 5, such as a printed circuit board (PCB). The length of IC 1 can be 300 μm, its width is 150 μm and its height is 100 μm. On the upper side of IC 1 there are: contacts 9, via which the IC is powered and controlled; and a plurality of light-emitting semiconductor chips 11, such as μLEDs. The light-emitting semiconductor chips 11 are arranged in groups of three along two rows at the two long sides of IC 1. In this embodiment, a plurality of groups 13 are provided, each group consisting of three light-emitting semiconductor chips 11 of red, green and blue. One pixel is assigned to each group 13 (in Figure 2 and 3 ) and are suitable for generating their light.

[0045] The light-emitting semiconductor chip 11 is mounted on the IC 1 and electrically connected thereto, so that the IC acts as a driver to operate the light-emitting semiconductor chip 11. In other words: the IC 1 serves not only as a driver IC but also as a carrier for the light-emitting semiconductor chip 11.

[0046] The contacts 9 of the IC 1 are connected to the contact areas VDD1, VDD2, GND, SDI, SDO, CLK on the substrate 5 via the wire contacts 14. The wire contacts 14 enable simple contacting. However, they have a space requirement that exceeds the height of the IC, and there is a risk of blocking the light-emitting semiconductor chips 11 if the wire contacts 14 pass over these light-emitting semiconductor chips. The latter is avoided in the embodiment by arranging the light-emitting semiconductor chips 11 at the long sides of the IC 1 and arranging the contacts 9 in the middle of the IC 1, wherein the wire contacts 14 extend over the wide sides of the IC 1.

[0047] Figure 4 Based on the previous Figure 2 and Figure 3 The intermediate product shown in is a schematic diagram of an embodiment of an intermediate product of a multi-pixel display device in a side sectional view in the region of the light-emitting semiconductor chip 11 . Figure 5 Schematic diagram showing the intermediate product in top view.

[0048] In the intermediate product shown, a lateral coating 17 is arranged on the IC 1, for example as an epoxy potting compound. This optional potting compound 17 achieves planarization. A structured layer is arranged on this potting compound 17. This can be a photostructured polymer layer 19 composed of or with EpoClad, for example. Alternatively, a polymer can also form the lateral coating of the IC 1. Of course, it has proven difficult to apply a photostructured material in sufficient thickness.

[0049] In the polymer layer 19, openings 21 are provided in the region of the group 13 of light-emitting semiconductor chips 11. The polymer material serves as a cladding material 27 for a light-conducting region 31 having a lower refractive index, which is located within the polymer layer 19 composed of a further material, the so-called core material 29. The openings 21 are coupling-in regions for the subsequent light-conducting region 31. The light emitted by the light-emitting semiconductor chip 11 propagates in the light-conducting region 31.

[0050] Figure 6 The side view shows the Figure 4 and Figure 5 A schematic diagram of an embodiment of an intermediate product multi-pixel display device is shown in FIG. Figure 7 A schematic diagram showing a multi-pixel display device in top view.

[0051] The multi-pixel display device has a light guiding element 35 which is formed on the IC 1 by means of structured polymer layers 19, 23, 25. In this exemplary embodiment, in addition to the already described Figure 4 In addition to the lower polymer layer 19 shown in the figure, an intermediate structured polymer layer 23 consisting of a cladding material 27 and a core material 29 and an upper structured polymer layer 25 are provided. In the intermediate layer 23, a light-emitting region 31 extending laterally (i.e. perpendicular to the IC height) is formed by the core material 29, which extends from the light-emitting semiconductor chip 11 to the pixel 40 and in which light is directed away from the light-emitting semiconductor chip 11 and the IC 1. In layer-by-layer production, a structured cladding material layer 27 and a core material 29 with a higher refractive index, for example made of EpoClad, are applied and light-structured. An opening 33 is provided in the upper structured polymer layer 25, which serves as a coupling-out region and by means of which light is guided to a display region 37 having pixels 40. The upper cladding material layer covers the planar waveguide formed by the core material 29 and allows light to leak upwards through the opening 33 at the location of the pixel 40.

[0052] For clarity, in Figure 6 Only two light guide regions 31 are shown in FIG. The other light guide regions are indicated by dotted lines.

[0053] On the upper side of the multi-pixel display device is a display area 37 with pixels 40, which can also be referred to as a display area. In order to achieve a good contrast, the upper side of the display area 37 is blackened, for example by a light-structured black polymer (e.g. Daxin BLRO301), which is applied as a black layer 39 with recesses 38 for the pixels 40. Alternatively, the light can also irradiate onto a diffuser, which is covered by a λ / 4 plate (also black on the outside) with a polarizer (not shown).

[0054] Figure 8 A schematic diagram of an embodiment of an intermediate product of a multi-pixel display device is shown in a top view. To avoid repetition, only the following are described. Figure 3 The difference in intermediate products is shown.

[0055] Wire contacts 14 lead from contacts 9 on IC 1 via the long sides of IC 1 and between groups 13 of light-emitting semiconductor chips 11 to contact areas 8 on substrate 5. IC 1 is arranged on substrate 5 between contact areas 8 so that its long sides are adjacent to the contact areas of the substrate. Contacts 9 on IC 1 are arranged in two rows on the longitudinal sides between light-emitting semiconductor chips 11.

[0056] and Figure 3 In contrast to the embodiment in , whose wire routing is advantageous for the optical properties, it is disadvantageous electrically due to the risk of short circuits, and Figure 8 The wire routing shown in is an electrically more advantageous, but optically slightly less advantageous variant.

[0057] In this exemplary embodiment, more than six contacts 9 are provided on the IC 1 , for example for further voltage potentials or reference potentials or further clock signals (for example for an image refresh rate), and an equal number of contact areas 8 are provided on the substrate 5 .

[0058] Fig. 9 A schematic diagram of an embodiment of an intermediate product of a multi-pixel display device is shown in a side cross-sectional view. To avoid repetition, only the following are described. Figure 2 The difference in intermediate products is shown.

[0059] In this embodiment, a planar connection 41 is provided instead of a wire contact 14. The planar connection extends between the contact and the contact area via an insulating layer 43 on the IC 1 and the potting compound 17 surrounding it to prevent short circuits. Such a planar connection is also referred to as a "planar interconnection". In this case, no optical attenuation is caused by the contact.

[0060] The embodiments described so far can also be used for curved or flexible displays.

[0061] Fig.10 A schematic diagram showing one embodiment of an intermediate product of a multi-pixel display device in side view. Fig.11 Schematic diagram showing the intermediate product in top view.

[0062] The multi-pixel display device comprises an integrated circuit 1 and a substrate 5 , on the upper side of which electrically conductive structures 7 are arranged, which also form contact regions 8 for supplying power and controlling the integrated circuit 1 .

[0063] IC 1 is mounted on contact surface 8 by means of flip chip mounting. In this embodiment, IC 1 has a square base area, which has a side length of 200 μm, for example. Its contacts 9 are arranged at the bottom side and are connected to contact areas 8 on substrate 5 by means of solder balls 45. Between substrate 5 and the bottom side, there is an underfill 47, also called "underfill" in English terms, which encapsulates solder balls 45 and can extend to the side edges of IC 1.

[0064] A plurality of light-emitting semiconductor chips, for example μLEDs, are mounted on the upper side of the IC 1 in the form of groups 13 each having a red, green and blue μLED. Each group 13 is assigned to a pixel ( Fig.10 and 11 The group 13 is arranged at the edge of the IC 1 in order to be able to guide the light to the pixels in a simple manner.

[0065] Flip-chip mounting increases the space available for optical components on the upper side of IC 1. However, this mounting is technically more difficult to implement since electrical contacts must be produced in the substrate of IC 1.

[0066] Fig.12 Based on the previous Fig.10 and Fig.11 The multiple pixels of the intermediate product shown in FIG. 1 are schematic diagrams showing one embodiment of an intermediate product of a display device in a side cross-sectional view. Fig.13 Schematic diagram showing the intermediate product in top view.

[0067] The optical collimation plate 49 is arranged above the IC 1 with the light-emitting semiconductor chips 11, so that the collimator 51 is arranged above each group 13 of the light-emitting semiconductor chips 11. The collimator 51 focuses the light and generates an approximately parallel beam path, so that the light emitted by the light-emitting semiconductor chip 11 will be emitted perpendicular to the upper side of the IC 1. In other words: the light from the μLED is collimated by means of the optical collimation plate 49. For this purpose, an injection molded part can be used as a refractive optical device for the optical collimation plate 49. Alternatively, a micro-optical method such as a microlens can be used, which is produced on glass by lithography of paint and remelting, or hot micro-embossing or nano-printing lithography.

[0068] Fig.14 Based on the previous Fig.12 and 13 The intermediate product shown in FIG. 1 is a schematic diagram showing an embodiment of an intermediate product of a multi-pixel display device in a side cross-sectional view.

[0069] An optical deflection plate 53 is arranged above the optical collimation plate 49, by means of which the light beam is deflected from the light-emitting semiconductor chip 11 on the IC 1 to the pixel 40. The optical deflection plate 53 can be manufactured, for example, by a LIGA process (photolithography, electroplating, molding). However, it can also be manufactured by grayscale lithography with paint. 3D printing is also possible.

[0070] The optical deflection plate 53 has a first reflector 55, which deflects the light emitted by the collimator 51 laterally away from the light-emitting semiconductor chip 11 and the IC 1, and deflects it again perpendicularly to the pixels 40 of the display area via a second reflector 57. The reflectors 55, 57 can be formed in a mirror-like manner. Ni with an Ag coating, glass with a metal coating (preferably Al or Ag) or polymers (thermoplastics, thermosetting plastics) can be considered as materials.

[0071] Fig.15 A side sectional view showing the Fig.14 A schematic diagram of an embodiment of an intermediate product multi-pixel display device is shown.

[0072] An optional optical focusing plate 59 is arranged above the optical deflection plate 53, by means of which the light for the pixel 40 is focused. In this embodiment, the light guiding element 35 with the optical collimation plate 49, the deflection plate 53 and the focusing plate 59 is a free beam optical device. The display area 37 arranged thereon has a black layer 39 with openings 38 for the pixels 40. A scattering layer 61 is arranged thereon.

[0073] The optical focusing plate 59 has a collimator 51 and / or a lens, by means of which a large amount of light is directed through the small opening 38 of the black layer 39 for the pixel 40. The collimated light will be directed in a focused manner through the aperture 38 in the black layer 39. Alternatively, the light can also enter a scattering lens and a λ / 4 plate with a polarizer (not shown). In the above embodiment, in the case of a pixel pitch of 1 mm, the distance from the light source to the screen on which the pixel 40 is located is significantly greater than 1 mm.

[0074] Figures 16 to 20 Various embodiments of an arrangement of a group 13 of semiconductor chips 11 emitting red, green and blue light on an IC 1 are shown in a top view.

[0075] Fig.16 A circular arrangement of groups 13 of light-emitting semiconductor chips 11 is shown in order to select the area of ​​the collimator lens to be as large as possible and to have sufficient space for deflection mirrors and free beam paths or, alternatively, for light deflection to pixels 40 .

[0076] Fig.17The arrangement of groups 13 of light-emitting semiconductor chips 11 along two concentric circles is shown, likewise in order to select the surface of the collimator lens to be as large as possible and to have sufficient space for deflection mirrors and free beam paths or, alternatively, for light deflection to pixels 40 .

[0077] Fig.18 The arrangement of the light-emitting semiconductor chips in the corners of a square base area of ​​the IC 1 is shown. This likewise has the advantages described above.

[0078] Fig.19 An array-shaped arrangement of groups 13 of light-emitting semiconductor chips 11 that beneficially distributes light to pixels 40 is shown in rows and columns.

[0079] Fig. 20 An arrangement along two rows is shown with the same advantages.

[0080] Fig.21 A schematic diagram of one embodiment of a multi-pixel display device is shown in side cross-sectional view.

[0081] The multi-pixel display device comprises an IC 1 mounted on a substrate 5 using flip-chip technology, such as has been combined with Figures 10 to 15 In the embodiment described above, a light-emitting semiconductor chip 11 is provided on the upper side of the IC. Fig.15 The embodiments in are different, so the description will focus on this aspect.

[0082] The light guiding element 35 on the IC 1 is likewise a free-beam optical device. The light guiding element is an optical reflector body 63, also referred to as an optical circuit board, and has a curved reflector 65, which is designed as a curved deflection mirror, with the aid of which the light emitted by the light-emitting semiconductor chip 11 is guided to the pixel 40. In addition to the deflection effect, the curved reflector 65 also has a lens function, so that fewer components are required. However, the production of such a curved reflector 65 is accompanied by increased costs. On the light guiding element 35 is a black layer 39 with an aperture 38 and an optional scattering layer 61, which increases the radiation angle of the pixel 40 and reduces glare due to its roughness. This is also called an anti-glare effect.

[0083] In this embodiment, the lenses are replaced by curved deflection mirrors. They fulfill the same function as the lenses. As a result, there are fewer components in the system. However, the mirrors are more expensive to manufacture.

[0084] Fig. 22 A schematic diagram of one embodiment of a multi-pixel display device is shown in side cross-sectional view.

[0085] The multi-pixel display device comprises an IC 1 mounted on a substrate 5 using flip-chip technology, such as having been combined with Figures 10 to 15The IC has a light-emitting semiconductor chip 11 on its top side. The multi-pixel display device is similar to the light-guiding element 35. Fig.15 The embodiments in are different, so the description will focus on this aspect.

[0086] The light guiding element 35 is positioned on the IC 1 by means of a fixing element 79, for example an adhesive. The light guiding element comprises a plurality of cable-shaped optical waveguides 71, also referred to as glass fibers, which extend from the underside of the light guiding element 35 to its upper side and are surrounded by a filling material 72, which serves as mechanical protection and for fixing the optical waveguides 71. At the upper and lower sides are plates with recesses 74, 76 as mounting aids 73, 75, in which the ends of the optical waveguides are positioned. The recesses 74, 76 are arranged above the group 13 of light-emitting semiconductor chips 11 and at the location of the pixels 40. The light of the light-emitting semiconductor chips 11 is coupled directly into the glass fibers 71. This can be done with or without optical means, as shown here. The glass fibers 71 are bent and thus guide the light to the corresponding pixels 40. There, the light is again focused on the holes 38 in the black layer 39 or on a scattering screen (not shown).

[0087] For producing the light guiding element 35, micromechanically produced plate-shaped mounting aids 73, 75 can be used, into which the glass fiber 71 can be accommodated in a passively calibrated manner. The intermediate space between the mounting aids 73, 75 can be filled with a rigid or flexible material 72. The mounting aids 73, 75 can still be present or absent in the finished product.

[0088] To mount the entire screen, it is contemplated to first mount the IC 1 on the substrate 5 and then mount the optical distributor device, or vice versa to first mount the IC on the optical distributor device and then mount it on the substrate 5. In the above embodiment, with a pixel pitch of 1 mm, the distance from the light source to the screen on which the pixel 40 is located is less than 2 mm.

[0089] Fig.23 An exemplary embodiment of a coupling-in region having a group 13 of light-emitting semiconductor chips 11 and an end region of a glass fiber 71 is shown.

[0090] The embodiment of the semiconductor chip 11 can be designed in the shape of a volume emitter so that its light is not only emitted upward, but also laterally. In order to couple in this light component, reflectors 81 are provided laterally of the light-emitting semiconductor chip 11, which guide the light to the end region of the glass fiber 71.

[0091] Particularly in the case of small μLEDs having an edge length of 10 μm or less and also emitting strongly to the side, it is expedient to provide a reflector on IC 1 for group 13 which is assigned to a pixel.

[0092] exist Fig. 22 and 23 The embodiments described in can also be used for curved or flexible displays.

[0093] The features of the exemplary embodiments can be combined with one another. The invention is not limited to the description based on the exemplary embodiments. Rather, the invention includes any new feature and any combination of features, which in particular includes any combination of features in the claims, even if the feature or the combination itself is not explicitly described in the claims or in the exemplary embodiments.

[0094] This application claims the priority of German patent application 102018129209.0, the disclosure content of which is incorporated herein by reference.

[0095] Description of Reference Numerals

[0096] 1 Integrated Circuit, IC

[0097] 3 Arrows

[0098] 5 Substrate

[0099] 7 Conductive structure

[0100] 8 Contact area

[0101] 9 Contacts

[0102] 11. Light-emitting semiconductor chip

[0103] 13. Assembly of light-emitting semiconductor chips

[0104] 14-wire contact

[0105] 17 Potting parts

[0106] 19th floor

[0107] 21 Opening

[0108] 23rd floor

[0109] 25th floor

[0110] 27 Coating material

[0111] 29 core material

[0112] 31 Light guide area

[0113] 33 Opening

[0114] 35 Light guiding element

[0115] 37 Display Area

[0116] 38 recess

[0117] 39 Black Layer

[0118] 40 pixels

[0119] 41 Plane connection

[0120] 43 Insulation layer

[0121] 45 Solder Balls

[0122] 47 Bottom filler

[0123] 49 Collimation Plate

[0124] 51 Collimator

[0125] 53 Deflector

[0126] 55 Reflector

[0127] 57 Reflector

[0128] 59 Focus Plate

[0129] 61 Scattering layer

[0130] 63 reflector body

[0131] 65 Curved Reflector

[0132] 71 Optical waveguide

[0133] 72 Filling material

[0134] 73 Mounting aids

[0135] 74 Opening

[0136] 75 Mounting aids

[0137] 76 Opening

[0138] 79 Fixing element

[0139] 81 Reflector

Claims

1. A multi-pixel display device having - an integrated circuit (1), - a plurality of light emitting semiconductor chips (11) arranged on the integrated circuit (1), - a display area (37) having a plurality of pixels (40), wherein Each of the light-emitting semiconductor chips (11) is assigned to one of the pixels (40), and more than one light-emitting semiconductor chip (11) is assigned to one pixel (40), - a light guiding element (35) arranged between the plurality of light-emitting semiconductor chips (11) and the display area (37) and suitable for guiding light from each of the plurality of light-emitting semiconductor chips (11) to the pixel (40) to which it is assigned, wherein the pixel (40) towards which the emitted light is guided is arranged laterally offset above the plurality of light-emitting semiconductor chips (11) assigned thereto, and wherein the light guiding element (35) having an upper side and a lower side has a plurality of light-guiding structures, the light-guiding structures respectively having a coupling-in region at the lower side and a coupling-out region at the upper side to the pixel (40), and wherein the plurality of light-emitting semiconductor chips (11) assigned to the pixel (40) are arranged overlapping with the coupling-in region of the light-guiding structure, and wherein the light-guiding structure includes a coupling-out region to the pixel (40).

2. The multi-pixel display device according to claim 1, wherein: A reflector (81) is arranged laterally of a light-emitting semiconductor chip (11) or a plurality of light-emitting semiconductor chips (11) in order to guide laterally emitted light onto the coupling-in region.

3. The multi-pixel display device according to claim 1 or 2, wherein: The light guiding element (35) has a plurality of structured layers (19, 23, 25) with light guiding regions (31).

4. The multi-pixel display device according to claim 1 or 2, wherein: The light guiding element (35) has at least one collimator (51) or at least one lens.

5. The multi-pixel display device according to claim 1 or 2, wherein: The light guiding element (35) has at least one reflector (55, 57, 65) for deflecting light.

6. The multi-pixel display device according to claim 1 or 2, wherein: The light guiding element (35) has at least one buncher for bunching the light.

7. The multi-pixel display device according to claim 1 or 2, wherein: The light guiding element (35) has at least one optical waveguide (71).

8. The multi-pixel display device according to claim 1 or 2, wherein: The light emitting semiconductor chips (11) or a group (13) of light emitting semiconductor chips (11) are arranged on the integrated circuit (1) along one or more circles or along a straight line or in an array.

9. The multi-pixel display device according to claim 1 or 2, wherein: The display area (37) has a dark layer (39) with recesses (38).

10. The multi-pixel display device according to claim 1 or 2, wherein: The display area (37) has a scattering layer (61).

11. The multi-pixel display device according to claim 1 or 2, further comprising a substrate (5), the integrated circuit (1) being arranged on the substrate and being electrically conductively connected to contact areas (8) on the substrate (5).

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