Display device and projection system

Abstract

The invention discloses a display device and a projection system, and the display device comprises a display screen which comprises a plurality of pixel islands; each pixel island comprises a plurality of pixels emitting light rays with the same color, and the colors of the light rays emitted by at least part of the pixel islands are different; the light angle adjusting piece is located on the light emitting side of the display screen, and the light angle adjusting piece is used for adjusting the emergent light of each pixel island to be emitted to a set angle; and the at least one optical waveguide is located on the light emitting side of the light angle adjusting piece, and the at least one optical waveguide is used for receiving the light emitted by the light angle adjusting piece and enabling the light to be emitted in parallel. According to the full-color display device, the light rays with different colors emitted by the pixel islands in the display screen enter the optical waveguide after the emitting angles are adjusted through the light ray angle adjusting piece, the optical waveguide enables the light rays with different colors to be emitted in the same area in parallel, and therefore the light rays with different colors can be fused together, and full-color display is achieved.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a display device and a projection system. Background Art

[0002] Micro Light Emitting Diode (Micro LED) display is a new generation of display technology with the advantages of high brightness, low energy consumption, long life, and self-luminescence. In order to achieve full-color display, a mass transfer process is usually used to produce Micro LED products, but this will result in high costs and low product yields. Another commonly used method for achieving full-color display is the optical lens method, which places red, green, and blue display screens on three surfaces of an X-prism respectively, and sets a wavelength-selective reflective film in the X-prism to achieve light combination. However, this method requires three display screens and also has the problem of high cost. Therefore, it is urgent to find a simpler and more efficient full-color display method. Summary of the invention

[0003] The present invention provides a display device and a projection system for realizing full-color display more simply and efficiently.

[0004] In one aspect, the present invention provides a display device, comprising: a display screen, the display screen comprising a plurality of pixel islands; the pixel islands comprising a plurality of pixels emitting light of the same color, at least some of the pixel islands emitting light of different colors;

[0005] A light angle adjustment member, located at the light-emitting side of the display screen, and used to adjust the emitted light of each pixel island to emit at a set angle;

[0006] At least one optical waveguide is located at the light-emitting side of the light angle adjusting member, and the at least one optical waveguide is used to receive the light emitted by the light angle adjusting member and make the light emitted in parallel.

[0007] In some embodiments of the present invention, the optical waveguide includes an incoupling region, an expansion region, a light transmission region, and an outcoupling region; the incoupling region and the expansion region are adjacently arranged in a first direction, the outcoupling region and the expansion region are arranged at a set distance in a second direction, the second direction is orthogonal to the first direction, and the light transmission region is located between the expansion region and the outcoupling region;

[0008] The outgoing light of the light angle adjusting member is incident from the coupling-in area into the interior of the optical waveguide, is expanded in the expansion area, and then is emitted from the coupling-out area after undergoing multiple total reflections in the light transmission area.

[0009] In some embodiments of the present invention, the width of the expansion region in the first direction is greater than the width of the coupling region in the first direction, and the width of the outcoupling region in the second direction is greater than the width of the coupling region in the second direction.

[0010] In some embodiments of the present invention, the number of the light waveguide is one; or the number of the light waveguide is equal to the number of color types of the light emitted by the display screen.

[0011] In some embodiments of the present invention, the display screen includes three pixel islands, and the three pixel islands emit light of three colors respectively; the display device includes three optical waveguides, and the three optical waveguides are used to receive and transmit the light of the three colors respectively; the three optical waveguides are arranged parallel to each other;

[0012] The three optical waveguides include a first optical waveguide, a second optical waveguide and a third optical waveguide, wherein an orthographic projection of an incoupling region of the first optical waveguide on the third optical waveguide, an orthographic projection of an incoupling region of the second optical waveguide on the third optical waveguide and the incoupling region of the third optical waveguide do not overlap with each other;

[0013] An orthographic projection of the outcoupling region of the first optical waveguide on the third optical waveguide, an orthographic projection of the outcoupling region of the second optical waveguide on the third optical waveguide, and the outcoupling region of the third optical waveguide overlap.

[0014] In some embodiments of the present invention, the light angle adjustment member includes a plurality of adjustment parts, and the plurality of adjustment parts are arranged in one-to-one correspondence with the plurality of pixel islands; the size of each of the adjustment parts is equal to the size of the corresponding pixel island.

[0015] In some embodiments of the present invention, the adjustment portion includes at least one collimating lens.

[0016] In some embodiments of the present invention, when the adjustment portion includes a plurality of collimating lenses, the plurality of collimating lenses are arranged in an array;

[0017] The collimating lens is arranged corresponding to the light emitting area of ​​at least one pixel in the pixel island, and is used for collimating the outgoing light of the corresponding pixel and emitting it at a set angle.

[0018] In some embodiments of the present invention, the light angle adjusting member is a collimating lens, and the outgoing light of the display screen is incident on the collimating lens.

[0019] In some embodiments of the present invention, the optical waveguide includes one or more of a geometric optical waveguide, a diffractive optical waveguide and a holographic optical waveguide.

[0020] Another aspect of an embodiment of the present invention provides a projection system, comprising a beam expander lens assembly and any one of the above display devices;

[0021] The beam expander group is located at the light output side of the at least one optical waveguide, and the parallel light emitted from the optical waveguide is expanded by the beam expander group and then output in parallel.

[0022] The beneficial effects of the present invention are as follows:

[0023] The present invention provides a display device and a projection system, wherein the display device comprises: a display screen, the display screen comprises a plurality of pixel islands; the pixel islands comprise a plurality of pixels emitting light of the same color, and the colors of the emitted light of at least some of the pixel islands are different; a light angle adjustment member located on the light-emitting side of the display screen, the light angle adjustment member is used to adjust the emitted light of each pixel island to emit at a set angle; at least one optical waveguide is located on the light-emitting side of the light angle adjustment member, and at least one optical waveguide is used to receive the light emitted by the light angle adjustment member and emit the light in parallel. The light of different colors emitted by each pixel island in the display screen is incident on the optical waveguide after the emission angle is adjusted by the light angle adjustment member, and the optical waveguide makes the light of different colors emit in parallel in the same area, so that the light of different colors can be merged together to achieve full-color display. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings introduced below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figure 1 One of the structural schematic diagrams of the display device provided by the embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the structure of a display screen provided by an embodiment of the present invention;

[0027] Figure 3 One of the structural schematic diagrams of the light angle adjustment member provided in an embodiment of the present invention;

[0028] Figure 4 A second structural schematic diagram of a light angle adjustment member provided in an embodiment of the present invention;

[0029] Figure 5 A second structural schematic diagram of a display device provided by an embodiment of the present invention;

[0030] Figure 6 A schematic diagram of the arrangement of the optical waveguide provided in an embodiment of the present invention;

[0031] Figure 7 A schematic diagram of the structure of a first optical waveguide provided in an embodiment of the present invention;

[0032] Figure 8 A schematic diagram of the structure of a second optical waveguide provided by an embodiment of the present invention;

[0033] Fig. 9 A schematic diagram of the structure of a third optical waveguide provided in an embodiment of the present invention;

[0034] Fig.10 A schematic structural diagram of a beam expander assembly provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0036] In the production process of Micro LED display, after the epitaxial growth of Micro LED chip is completed, the Micro LED chip needs to be transferred to the driving backplane. Currently, mass transfer technology is usually used to achieve this process. Each display unit of Micro LED display needs to include a group of red, green and blue pixels, so that full-color images can be displayed by controlling the on and off of each display unit. However, this pixel arrangement is difficult to transfer in mass, which will lead to low product yield and high cost.

[0037] To achieve full-color display, optical methods can also be used to synthesize light of different colors. The commonly used light combining method is the optical lens method. The optical lens method places independent red, green, and blue display screens on the three surfaces of the X-prism respectively, and sets a wavelength selective reflective film in the X-prism to make the red, green, and blue lights emit in the same direction to achieve light combining. However, this method requires three display screens and also has the problem of high cost.

[0038] In view of this, an embodiment of the present invention provides a display device, which can realize full-color display more simply and efficiently and reduce costs.

[0039] Figure 1This is one of the structural schematic diagrams of the display device provided by the embodiment of the present invention.

[0040] like Figure 1 As shown, the display device may include a display screen 10, a light angle adjustment member 20, and at least one optical waveguide 30. The display screen 10 includes a plurality of pixel islands, each of which includes a plurality of pixels emitting light of the same color, and at least some of the pixel islands have different colors of emitted light; the light angle adjustment member 20 is located on the light-emitting side of the display screen 10, and can be used to adjust the emitted light of each pixel island to emit at a set angle; at least one optical waveguide 30 is located on the light-emitting side of the light angle adjustment member 20, and can be used to receive the light emitted by the light angle adjustment member 20 and make the light emit in parallel.

[0041] The light emitted from each pixel in the display screen 10 can be adjusted to collimated light after passing through the light angle adjustment member 20, but the light emitted from each pixel island still has a certain divergence angle after passing through the light angle adjustment member 20. At this time, the light of each color cannot completely overlap, and the color area that can be observed by the human eye is small. By designing the structure of the coupling end and the coupling end of the optical waveguide 30, light of different colors can be emitted in parallel within a certain area, so that the output light of the light angle adjustment member 20 can be merged together after entering the optical waveguide 30, thereby realizing full-color display.

[0042] Figure 2 A schematic diagram of the structure of a display screen provided by an embodiment of the present invention.

[0043] like Figure 2 As shown, the display screen 10 may include three pixel islands, namely a red pixel island 11, a green pixel island 12 and a blue pixel island 13, wherein the red pixel island 11 includes a plurality of red Micro LED chips, the green pixel island 12 includes a plurality of green Micro LED chips, and the blue pixel island 13 includes a plurality of blue Micro LED chips. The Micro LED chips emitting light of the same color in the display screen 10 are arranged in a certain area. In the process of mass transfer, Micro LED chips of different colors can be transferred in batches, the transfer difficulty is relatively lower and the fault tolerance rate is higher, which is conducive to improving the production yield of display products and reducing production costs.

[0044] It is understandable that each pixel of the display screen 10 can also use a light emitting diode (Light Emitting Diode, LED), Mini LED or organic light emitting diode (Organic Light Emitting Diode, OLED) as a light emitting device, and the color of light emitted by each pixel island includes but is not limited to red, green and blue. The number of pixel islands is not limited to three. The area of ​​each pixel island and the number of pixels contained therein can be the same or different. The setting method of the pixel islands in the display screen 10 can be adjusted according to the requirements of the display product. The embodiment of the present invention is not limited here. The following is an example in which the display screen 10 includes three pixel islands of red, green and blue, and the three pixel islands of red, green and blue are equal in size.

[0045] Figure 3 One of the structural schematic diagrams of the light angle adjustment member provided in an embodiment of the present invention; Figure 4 The second structural schematic diagram of the light angle adjustment member provided in the embodiment of the present invention.

[0046] like Figure 1 , Figure 3 and Figure 4 As shown, the light angle adjustment member 20 may include a plurality of adjustment parts, and the plurality of adjustment parts are arranged in one-to-one correspondence with the plurality of pixel islands, and the size of each adjustment part is equal to the size of the corresponding pixel island. The adjustment part includes at least one collimating lens R. When the adjustment part includes a plurality of collimating lenses R, the plurality of collimating lenses R are arranged in an array, and the collimating lens R is arranged in a light emitting area corresponding to at least one pixel in the pixel island. The collimating lens R can be used to collimate the outgoing light of the corresponding pixel and emit it at a set angle.

[0047] Corresponding to Figure 2 In the display screen 10 shown, the light angle adjustment member 20 may include three adjustment parts, which are respectively referred to as the first adjustment part 21, the second adjustment part 22 and the third adjustment part 23 for the convenience of description, wherein the first adjustment part 21 is set corresponding to the red light pixel island 11, the second adjustment part 22 is set corresponding to the green light pixel island 12, and the third adjustment part 23 is set corresponding to the blue light pixel island 13.

[0048] like Figure 3 As shown, the first adjustment part 21, the second adjustment part 22 and the third adjustment part 23 can all adopt a collimating lens R, the size of the collimating lens R is equal to the size of the corresponding pixel island, the outgoing light of each pixel is collimated after passing through the corresponding collimating lens R, the outgoing light of each pixel island can form a divergent light beam after passing through the corresponding collimating lens R, and the red, green and blue light beams have a partial overlapping area, and the light beam emitted by the display screen 10 is a divergent light beam as a whole after passing through the light angle adjustment member 20.

[0049] like Figure 4 As shown, the first adjustment part 21, the second adjustment part 22 and the third adjustment part 23 can all include a plurality of collimating lenses R, and the plurality of collimating lenses R constitute a collimating lens array, and each collimating lens R is arranged corresponding to a light emitting area of ​​at least one pixel. In some embodiments, the collimating lenses R can be arranged one-to-one in correspondence with the pixels in the display screen 10, and the light emitted from the corresponding pixel can be adjusted to collimated light by adjusting the shape and curvature of each collimating lens R.

[0050] Figure 5 The second structural schematic diagram of the display device provided in the embodiment of the present invention.

[0051] like Figure 5 As shown, the light angle adjustment member 20 may also adopt a collimating lens R, the size of the collimating lens R is at least equal to the size of the display screen 10, so that the outgoing light of the display screen 10 can be incident on the collimating lens R, and the outgoing light of each pixel in the display screen 10 can be collimated after passing through the collimating lens R, and the light emitted by each pixel island can converge toward the optical axis direction of the collimating lens R.

[0052] In the embodiment of the present invention, the number, shape, curvature and other parameters of the collimating lenses R corresponding to each pixel island can be adjusted according to design requirements, so as to achieve fine control of the outgoing light of the corresponding pixel in the display screen 10, so that it is emitted in a set direction to facilitate the incident light into at least one optical waveguide 30 for light combination.

[0053] Reference Figure 1 and Figure 5 In the embodiment of the present invention, the number of the optical waveguide 30 is one, or the number of the optical waveguide 30 is equal to the number of color types of the light emitted by the display screen 10. The types of the optical waveguide 30 may include one or more of a geometric optical waveguide, a diffractive optical waveguide and a holographic optical waveguide.

[0054] When the number of optical waveguides 30 in the display device is one, a coupling-in region and a coupling-out region are set in the optical waveguide 30. By adaptively designing the structure of the coupling-in region, light rays of different colors emitted from the display screen 10 can be coupled into an optical waveguide 30, and light rays of different colors are transmitted inside the optical waveguide 30. By adaptively designing the structure of the coupling-out region, light rays of different colors can all be emitted from the coupling-out region of the optical waveguide 30, thereby completing light combination.

[0055] When the number of optical waveguides 30 in the display device is equal to the number of color types of light emitted by the display screen 10, each optical waveguide 30 can be used to receive and transmit light of one color. The coupling-in regions of each optical waveguide 30 are arranged separately and the coupling-out regions are arranged overlappingly, so that light of different colors can be coupled into the corresponding optical waveguide 30 respectively and transmitted in the corresponding optical waveguide 30, and then emitted in the same area to complete light combination. Figure 2 In the display screen 10 shown, three optical waveguides 30 may be provided in the display device, and the three optical waveguides 30 may respectively receive and transmit three colors of light emitted from the display screen 10 .

[0056] Figure 6 A schematic diagram of the arrangement of optical waveguides provided in an embodiment of the present invention.

[0057] like Figure 6 As shown, the three optical waveguides include a first optical waveguide 31, a second optical waveguide 32 and a third optical waveguide 33, which are arranged in parallel with each other, wherein the first optical waveguide 31 is used to receive and transmit green light, the second optical waveguide 32 is used to receive and transmit blue light, and the third optical waveguide 33 is used to receive red light. In specific implementation, the arrangement order of the optical waveguides can be changed, which is not limited in the embodiment of the present invention.

[0058] The light angle adjusting member 20 adjusts the light of different colors emitted from the display screen 10 to be emitted toward the coupling-in area 301 of the corresponding light waveguide, so that the light of different colors can be coupled into the corresponding light waveguide. To achieve a better coupling effect, in the embodiment of the present invention, the orthographic projection of the coupling-in area 301 of the first light waveguide 31 on the third light waveguide 33, the orthographic projection of the coupling-in area 301 of the second light waveguide 32 on the third light waveguide 33 and the coupling-in area 301 of the third light waveguide 33 do not overlap with each other, that is, the coupling-in areas 301 of the first light waveguide 31, the second light waveguide 32 and the third light waveguide 33 are arranged separately.

[0059] The orthographic projection of the outcoupling area 304 of the first optical waveguide 31 on the third optical waveguide 33 and the orthographic projection of the outcoupling area 304 of the second optical waveguide 32 on the third optical waveguide 33 overlap with the outcoupling area 304 of the third optical waveguide 33, that is, the outcoupling areas 304 of the three optical waveguides are arranged in an overlapping manner, and the red, green and blue light beams are emitted from the outcoupling areas 304 of the corresponding optical waveguides, and the emission areas of the three-color light beams are the same, so that the three-color light beams can be combined into one beam and emitted in parallel in the same direction.

[0060] Figure 7 A schematic diagram of the structure of a first optical waveguide provided in an embodiment of the present invention; Figure 8 A schematic diagram of the structure of a second optical waveguide provided by an embodiment of the present invention; Fig. 9 A schematic structural diagram of a third optical waveguide provided in an embodiment of the present invention.

[0061] Figure 7 , Figure 8 and Fig. 9 The specific structures of the first optical waveguide 31, the second optical waveguide 32 and the third optical waveguide 33 are shown. Figure 7 , Figure 8 and Fig. 9 As shown, the optical waveguide includes a coupling-in area 301, an expansion area 302, a light transmission area 303 and a coupling-out area 304, wherein the coupling-in area 301 and the expansion area 302 are adjacently arranged in a first direction X, the coupling-out area 304 and the expansion area 302 are arranged at a set distance in a second direction Y, the second direction Y is orthogonal to the first direction X, and the light transmission area 303 is located between the expansion area 302 and the coupling-out area 304. The light path transmission process in each optical waveguide is as follows: the outgoing light of the light angle adjustment member 20 is incident from the coupling-in area 301 to the inside of the corresponding optical waveguide, is expanded in the expansion area 302, and then is emitted from the coupling-out area 304 after multiple total reflections in the light transmission area 303.

[0062] The embodiment of the present invention can adjust the exit angles of light of different colors by making an adaptive design for the outcoupling region of the optical waveguide. Taking the diffraction optical waveguide as an example, the grating structure at the outcoupling end of the optical waveguide is configured to satisfy the following relationship:

[0063] d(sinθ 1 +sinθ 2 )=λ

[0064] Where d is the period of the grating, θ 1 represents the incident angle of the light, θ 2 represents the emission angle of the light, and λ represents the wavelength of the light received and transmitted by the optical waveguide.

[0065] In such Figure 6 In the optical waveguide arrangement shown, the outcoupling angle of the light emitted by the pixels at the same position of the red light pixel island and the blue light pixel island can be controlled to be consistent with the outcoupling angle of the light emitted by the pixels at the same position of the green light pixel island, so that the light emitted by the pixel island display screen provided by the embodiment of the present invention can achieve the same display effect as a conventional display screen after being combined by the light angle adjustment member and the optical waveguide.

[0066] In the optical waveguide provided by the embodiment of the present invention, the width of the expansion zone 302 in the first direction X can be greater than the width of the coupling zone 301 in the first direction X, and the width of the outcoupling zone 304 in the second direction Y can be greater than the width of the coupling zone 301 in the second direction Y. The width of the light beam coupled into the optical waveguide along the first direction X and the second direction Y are respectively equal to the width of the coupling zone 301 of the optical waveguide in the first direction X and the second direction Y. After the light beam is coupled into the optical waveguide, it is first expanded once along the first direction X in the expansion zone 302, and its width along the first direction X is expanded to be consistent with the width of the expansion zone 302 in the first direction X. The expanded light beam is transmitted to the outcoupling zone 304 in the light transmission zone 303 by total reflection, and then can be expanded again along the second direction Y in the outcoupling zone 304, and the width of the light beam along the second direction Y is expanded to be consistent with the width of the outcoupling zone 304 in the second direction Y. In the embodiment of the present invention, after the light angle adjusting member 20 is incident on the optical waveguide, the light can be expanded twice and fully emitted from the outcoupling region 304, thereby achieving a beam expansion effect and making the effective imaging range of the display device larger.

[0067] Based on the same inventive concept, an embodiment of the present invention further provides a projection system, which may include a collimator group and any one of the above-mentioned display devices, wherein the collimator group is located on the light-emitting side of at least one optical waveguide of the display device, and the parallel light emitted from the optical waveguide is still emitted in parallel after being expanded by the collimator group.

[0068] Fig.10 A schematic structural diagram of a beam expander assembly provided in an embodiment of the present invention.

[0069] In the display device provided by the embodiment of the present invention, the outcoupling end of the optical waveguide emits parallel light, and a beam expander group is arranged at the outcoupling end of the optical waveguide. The beam expander group is equivalent to imaging an infinitely far object. Fig.10 As shown, the beam expander group 40 can be composed of an objective lens group 41 and an eyepiece group 42. In this case, the beam expander group 40 is equivalent to a telescopic system, and the focal plane of the eyepiece group 42 is placed near the imaging surface of the objective lens group 41, so that the objective lens group 41 images the parallel light emitted from the light waveguide and then images it through the eyepiece group 42. The image can be magnified twice, thereby expanding the imaging range of the projection system, and the area where the human eye can observe clear images, namely the eyebox area, is increased.

[0070] In specific implementation, the eyepiece group 42 and the objective lens group 41 can each use a converging lens or a combination of multiple lenses. The specific structure of the beam expander group 40 can be adaptively designed according to the requirements of projection display, and the embodiment of the present invention is not limited here.

[0071] In the projection system provided by the embodiment of the present invention, light beams of different colors emitted by the pixel island display screen are collimated by the light angle adjustment component and combined by the optical waveguide, and then emitted in parallel to the beam expander group and then to the human eye. The light beams are amplified after passing through the optical waveguide and amplified again after passing through the beam expander group. The projection system can have a larger eyebox range while achieving full-color display. The projection system can be applied to head-up display (HUD) systems, near-eye display systems such as augmented reality (AR) and virtual reality (VR), and other products, and has broad application prospects.

[0072] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0073] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A display device, characterized in that: include: A display screen, the display screen comprising a plurality of pixel islands; The pixel island includes a plurality of pixels emitting light of the same color, and at least some of the pixel islands emit light of different colors; A light angle adjustment member, located at the light-emitting side of the display screen, and used to adjust the emitted light of each pixel island to emit at a set angle; At least one optical waveguide is located at the light-emitting side of the light angle adjusting member, and the at least one optical waveguide is used to receive the light emitted by the light angle adjusting member and make the light emitted in parallel.

2. The display device according to claim 1, wherein: The optical waveguide comprises an incoupling region, an expansion region, a light transmission region and an outcoupling region; the incoupling region and the expansion region are adjacently arranged in a first direction, the outcoupling region and the expansion region are arranged at a set distance in a second direction, the second direction is orthogonal to the first direction, and the light transmission region is located between the expansion region and the outcoupling region; The outgoing light of the light angle adjusting member is incident from the coupling-in area into the interior of the optical waveguide, is expanded in the expansion area, and then is emitted from the coupling-out area after undergoing multiple total reflections in the light transmission area.

3. The display device according to claim 2, wherein: The width of the extension region in the first direction is greater than the width of the coupling-in region in the first direction, and the width of the out-coupling region in the second direction is greater than the width of the coupling-in region in the second direction.

4. The display device according to claim 2, wherein: The number of the light waveguide is one; or the number of the light waveguide is equal to the number of color types of the light emitted by the display screen.

5. The display device according to claim 4, characterized in that The display screen includes three pixel islands, and the three pixel islands emit light of three colors respectively; the display device includes three optical waveguides, and the three optical waveguides are used to receive and transmit the light of the three colors respectively; the three optical waveguides are arranged in parallel with each other; The three optical waveguides include a first optical waveguide, a second optical waveguide and a third optical waveguide, wherein an orthographic projection of an incoupling region of the first optical waveguide on the third optical waveguide, an orthographic projection of an incoupling region of the second optical waveguide on the third optical waveguide and the incoupling region of the third optical waveguide do not overlap with each other; An orthographic projection of the outcoupling region of the first optical waveguide on the third optical waveguide, an orthographic projection of the outcoupling region of the second optical waveguide on the third optical waveguide, and the outcoupling region of the third optical waveguide overlap.

6. The display device according to any one of claims 1 to 5, characterized in that: The light angle adjustment member includes a plurality of adjustment parts, and the plurality of adjustment parts are arranged in one-to-one correspondence with the plurality of pixel islands; the size of each adjustment part is equal to the size of the corresponding pixel island.

7. The display device according to claim 6, wherein: The adjusting portion includes at least one collimating lens.

8. The display device according to claim 7, characterized in that: When the adjustment part comprises a plurality of collimating lenses, the plurality of collimating lenses are arranged in an array; The collimating lens is arranged corresponding to the light emitting area of ​​at least one pixel in the pixel island, and is used for collimating the outgoing light of the corresponding pixel and emitting it at a set angle.

9. The display device according to any one of claims 1 to 5, characterized in that: The light angle adjustment member adopts a collimating lens, and the outgoing light of the display screen is incident on the collimating lens.

10. The display device according to any one of claims 1 to 5, characterized in that: The optical waveguide includes one or more of a geometric optical waveguide, a diffractive optical waveguide and a holographic optical waveguide.

11. A projection system, characterized in that: A display device comprising a beam expander assembly and any one of claims 1 to 10; The beam expander group is located at the light output side of the at least one optical waveguide, and the parallel light emitted from the optical waveguide is expanded by the beam expander group and then output in parallel.

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