Portable display device based on medium-free holographic projection

Abstract

The embodiment of the utility model provides a portable display device based on medium-free holographic projection. The portable display device comprises a main body; the shell comprises a first shell body and a second shell body which are arranged in a double-layer mode. The first shell is a transparent piece arranged on the outer layer, and the second shell is a non-transparent piece arranged on the inner layer; the main body is arranged in a mounting cavity formed by the second shell; and the supporting piece is arranged at the bottom of the second shell, is transparent and is used for supporting the second shell. According to the invention, the color difference between the first shell and the second shell is designed; wherein the first shell is a transparent piece, the second shell is a non-transparent piece, the visual effect that the device is suspended can be effectively created through the color difference between the first shell and the second shell, unique visual experience is provided, and the immersion feeling of a user is enhanced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of holographic projection technology, and in particular to a portable display device based on medium-free holographic projection. BACKGROUND

[0002] With the development of display technology, medium-free holographic projection technology, as a new display method, has gradually attracted people's attention. The display device in the related art usually relies on a physical screen to present an image, which not only limits the design flexibility of the display device, but also is inconvenient to use in some application scenarios (such as outdoors or special environments). For example, in outdoor activities, temporary exhibitions, or special environments, the presence of a physical screen brings many inconveniences, such as large volume, heavy weight, and inconvenience to carry. In order to solve these problems, medium-free holographic projection technology emerges as the times require, which can directly form a three-dimensional image in the air without the support of a physical screen, thereby realizing more flexible and diversified display effects.

[0003] The portable display device in the related art is relatively single in appearance design, and the inner and outer layers of the shell are usually uniform or similar in color, which makes the device lack visual hierarchy and stereoscopic effect, and cannot present a similar floating effect, affecting the user's visual experience and failing to provide a unique visual experience. This makes it difficult for users to feel novelty and attractive effects during use. CONTENT OF THE UTILITY MODEL

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present disclosure is to provide a portable display device based on medium-free holographic projection to solve the problems in the related art.

[0005] The first aspect of the present disclosure provides a portable display device based on medium-free holographic projection, comprising:

[0006] a main body;

[0007] a shell comprising a first shell and a second shell arranged in double layers; the first shell is a transparent piece arranged on the outer layer, and the second shell is an opaque piece arranged on the inner layer; the main body is arranged in a mounting cavity formed by the second shell;

[0008] a support piece arranged at the bottom of the second shell and being transparent to support the second shell.

[0009] In an embodiment of the first aspect, an installation opening is arranged at the top of the shell.

[0010] The main body comprises:

[0011] a light waveguide plate arranged in the mounting cavity and corresponding to the installation opening;

[0012] A light source is arranged in the mounting cavity, and an emitting surface of the light source forms an inclined angle with a surface of the light waveguide plate facing the mounting cavity, so as to form an aerial image of a light emitting pattern on the light source above a surface of the light waveguide plate facing away from the mounting cavity.

[0013] In an embodiment of the first aspect, further comprising:

[0014] A mounting structure is arranged in the mounting cavity, and the mounting structure comprises an optical cavity, an inner wall of the optical cavity is formed with a first mounting portion for arranging the light source, a second mounting portion for arranging the light waveguide plate, and at least one reflecting portion facing the second mounting portion.

[0015] In an embodiment of the first aspect, the first mounting portion is implemented as a mounting port or a slot; and / or, the first mounting portion is implemented as a slot matched with the light waveguide plate.

[0016] In an embodiment of the first aspect, a support portion is formed between the inner wall of the mounting cavity and the mounting port, and a supported portion is formed on the support portion.

[0017] In an embodiment of the first aspect, a mounting port is arranged at the top of the shell; and the mounting port is provided with a light transmission plate.

[0018] In an embodiment of the first aspect, the light transmission plate is unidirectional light emitting from the inside to the outside of the mounting cavity.

[0019] In an embodiment of the first aspect, the mounting cavity comprises a first mounting area provided with the main body, and a second mounting area communicated with the first mounting area.

[0020] The second mounting area is provided with circuit components electrically connected with the main body.

[0021] In an embodiment of the first aspect, a wiring portion is arranged on the inner wall of the mounting cavity, and the wiring portion comprises a wiring through hole for arranging an electrical connection line between the main body and the circuit components.

[0022] In an embodiment of the first aspect, the circuit components comprise a control panel exposed at the bottom of the shell.

[0023] The beneficial effects of the present disclosure are: the color difference design between the first shell and the second shell; wherein the first shell is a transparent piece, and the second shell is an opaque piece, and the color difference between the two can effectively create a visual effect of the device floating, provide a unique visual experience, and enhance the immersion of the user. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1FIG. 5 is a schematic view of a cross section of a portable display device based on medium-free holographic projection in an embodiment of the present disclosure, along a direction a.

[0025] Figure 2 FIG. 6 is a schematic view of a structure of a mounting structure in a portable display device based on medium-free holographic projection in an embodiment of the present disclosure.

[0026] Figure 3 FIG. 7 is a schematic view of a cross section of a wiring portion of a portable display device based on medium-free holographic projection in an embodiment of the present disclosure.

[0027] Reference Signs:

[0028] Body 100; light waveguide plate 110; light source 120;

[0029] Housing 200; first housing 210; second housing 220; mounting cavity 221; first mounting area 2211; second mounting area 2212; light-transmitting plate 230;

[0030] Support 300;

[0031] Mounting structure 400; top 401; first sidewall 402; optical cavity 410; first mounting portion 420; second mounting portion 430; reflecting portion 440;

[0032] Supporting portion 510; supported portion 520; reinforcing rib 530;

[0033] Wiring through hole 600. DETAILED DESCRIPTION

[0034] The above embodiments of the present disclosure are merely used to illustrate the technical solutions of the present disclosure, and the present disclosure can be implemented with other embodiments without departing from the spirit of the present disclosure. The embodiments of the present disclosure and the features of the embodiments can be combined with each other under the condition of no conflict, and the embodiments of the present disclosure can be implemented or applied in other different embodiments.

[0035] The above embodiments of the present disclosure are merely used to illustrate the technical solutions of the present disclosure, and the present disclosure can be implemented with other embodiments without departing from the spirit of the present disclosure. The embodiments of the present disclosure and the features of the embodiments can be combined with each other under the condition of no conflict, and the embodiments of the present disclosure can be implemented or applied in other different embodiments.

[0036] In the description of the present disclosure, the expressions "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like mean that the specific feature, structure, material or characteristic accompanying the embodiments or examples is included in at least one embodiment or example of the present disclosure. Also, the specific feature, structure, material or characteristic accompanying an embodiment or example can be combined in an appropriate manner with the specific feature, structure, material or characteristic accompanying other embodiments or examples and other embodiments or examples in the present disclosure. In addition, the embodiments or examples and the features of the embodiments or examples expressed in the present disclosure can be combined and combined by those skilled in the art without contradiction.

[0037] In addition, the terms "first", "second", etc. are used only for the purpose of description and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a group" is two or more, unless specifically limited.

[0038] In order to clearly illustrate the present disclosure, devices irrelevant to the description are omitted, and the same reference numerals are given to the same or similar constituent elements throughout the description.

[0039] Throughout the description, when it is said that a device is "connected" to another device, it includes not only the case of "direct connection", but also the case of "indirect connection" in which other elements are placed therebetween. In addition, when it is said that a device "includes" a certain constituent element, unless specifically stated to the contrary, other constituent elements are not excluded, but it means that other constituent elements can also be included.

[0040] Although the terms first, second, etc. are used herein to refer to various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first interface and a second interface, etc. are indicated. Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise", "comprising", "include" and / or "including" mean the presence of stated features, steps, operations, elements, modules, items, species, and / or groups but do not preclude the presence or addition of one or more other features, steps, operations, elements, modules, items, species, and / or groups. The terms "or" and "and / or" as used herein are to be interpreted as inclusive, or meaning either or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". This exception occurs only when the combination of elements, functions, steps or operations is inherently mutually exclusive.

[0041] The professional terms used herein are only used to refer to specific embodiments and are not intended to limit the disclosure. The singular form used herein, unless the statement explicitly indicates the opposite meaning, also includes the plural form. The meaning of "include" used in the specification is to specify the specific features, regions, integers, steps, operations, elements and / or components, and does not exclude the presence or addition of other features, regions, integers, steps, operations, elements and / or components.

[0042] Although not defined differently, the technical terms and scientific terms used herein include the meanings commonly understood by those skilled in the art to which the disclosure belongs. The terms defined in the commonly used dictionary are additionally explained to have meanings consistent with the relevant technical literature and the currently prompted messages, unless defined, and should not be interpreted as ideal or very formal meanings.

[0043] The portable display device in the related art is relatively single in appearance design, and the inner and outer layers of the shell are usually uniform or similar in color, which makes the device lack visual hierarchy and stereoscopic effect, and cannot present a similar floating effect, affecting the user's visual experience and failing to provide a unique visual experience. This makes it difficult for users to feel novelty and attractive effect during use.

[0044] The present disclosure creates a color difference between the first shell and the second shell; wherein the first shell is a transparent piece, and the second shell is an opaque piece, and the color difference between the two can effectively create a visual effect of the device floating, provide a unique visual experience, and enhance the user's sense of immersion.

[0045] The medium-free aerial imaging technology uses the Pepper's Ghost and its optical principle to project a mirror image of a light source in the air (without a projection carrier medium) through special imaging glass. The technical principle is understood before the implementation of the present disclosure, but the present disclosure does not involve improvement of the imaging principle, but only application improvement of the structure.

[0046] Figure 1 FIG. 1 is a schematic view of a portable display device based on medium-free holographic projection according to an embodiment of the present disclosure.

[0047] The present disclosure can provide a portable display device based on medium-free holographic projection, wherein in Figure 1 In the example, the portable display device includes a main body 100, a shell 200, and a support 300.

[0048] The shell 200 comprises a first shell 210 and a second shell 220 arranged in double layers; the first shell 210 is a translucent or transparent member arranged in an outer layer, and the second shell 220 is an opaque member arranged in an inner layer; the main body 100 is arranged in a mounting cavity 221 formed by the second shell 220;

[0049] The support member 300 is of the same color as the first shell 210 and is arranged at the bottom of the second shell 220 to support the second shell 220.

[0050] Specifically, in Figure 1 In examples, the horizontal cross section of the shell 200 is in an elliptical shape, and in other embodiments, the shell 200 can also be implemented as a cuboid and other shapes, and the shape of the shell 200 can be adjusted according to actual use conditions. In Figure 1 In examples, in order to be aesthetically pleasing and considering the practicability of the product, the first shell 210 is arranged as a transparent or translucent member, and the second shell 220 is arranged as an opaque member, and in some embodiments, the second shell 220 can be arranged as black to form a color difference with the first shell 210. Since the first shell 210 is transparent or translucent, the second shell 220 arranged in the first shell 210 appears to have a "suspended" effect. It should be noted that the color of the second shell 220 can be arranged according to actual use conditions, and preferably, the color of the second shell 220 has a large visual contrast with the color of the first shell 210, but the material of the first shell 210 should be transparent or translucent to make the second shell 220 present the "suspended" effect as described above, so that the portable display device can present a better viewing effect.

[0051] In some embodiments, in order to present the "suspended" effect, in addition to arranging the first shell 210 as translucent, the second shell 220 also needs to be supported by a transparent support member 300, so that the second shell 220 presents the "suspended" effect as Figure 1 shown. In Figure 1In an example, a support 300 is arranged below the second housing 220 to support the second housing 220, and the support 300 is arranged in the first housing 210. Optionally, the support 300 can be the same color as the first housing 210, and the support 300 should be the same material as the first housing 210, both transparent or translucent, to ensure the "suspended" effect. In some embodiments, a support structure can also be arranged on the inner wall of the first housing 210 to form the support 300, which supports the second housing 220 in the first housing 210 like "suspended". The arrangement of the support 300 can be selected according to the actual use; wherein the support can be arranged as a support ring around the inner side wall of the first housing 210, and the support ring is glued and fixed with the inner side wall of the first housing 210 or integrally formed, wherein the fixing method of the support and the inner side wall of the first housing 210 can be adjusted according to actual needs.

[0052] Optionally, an installation opening is arranged at the top of the housing 200.

[0053] The main body 100 comprises:

[0054] The light waveguide plate 110 is arranged in the installation cavity 221 and corresponds to the installation opening.

[0055] The light source 120 is arranged in the installation cavity 221, and the light emitting surface of the light source 120 forms an inclined angle with the surface of the light waveguide plate 110 facing the installation cavity 221, so as to form an aerial imaging of the light emitting pattern on the light source 120 above the surface of the light waveguide plate 110 away from the installation cavity 221.

[0056] Specifically, in some embodiments, the light waveguide plate 110 is installed at the position of the installation opening. The specific structure of the light waveguide plate 110 has been disclosed in detail in two prior applications with application numbers CN201911021229.2 and CN201810155532.0, and thus will not be described here.

[0057] Optionally, the light source 120 can be a laser, an electronic screen or other light source 120. In some embodiments, the light source 120 can form an image by light projection, such as a clock image that can dynamically change over time, and then the projected light of the light source 120 is refracted by the light waveguide plate 110 to form a floating imaging of the clock image in the air, so that the portable display device can be used as a medium-free holographic projection clock. The content projected by the light source 120 can be set according to actual use requirements, such as projection images of other patterns such as petals. Figure 1In an example, the light source 120 is placed at an angle with the light waveguide plate 110, so that the light projected by the light emitting surface of the light source 120 can be projected onto the light waveguide plate 110, and the light rays are outputted after turning on the light waveguide plate 110, so as to form a three-dimensional image in the air through the light waveguide plate 110. Figure 1 In an example, the image is presented in the air, wherein the presented image is symmetrical with the light waveguide plate 110 as the axis and is axisymmetric with the light source 120. Due to the special optical characteristics of the light waveguide plate 110, the light rays can propagate in the air and form a stable three-dimensional image.

[0058] Optionally, the portable display device further comprises:

[0059] An installation structure 400 is arranged in the installation cavity 221, and the installation structure 400 comprises an optical cavity 410, the inner wall of the optical cavity 410 is formed with a first installation part 420 for arranging the light source 120, a second installation part 430 for arranging the light waveguide plate 110, and at least one reflecting part 440 facing the second installation part 430.

[0060] As an example, the installation structure 400 is a structure in which a plurality of walls are connected in a closed loop. The top part 401 of the installation structure 400 can form the second installation part 430 for installing the light waveguide plate 110. In some embodiments, the second installation part 430 can be a slot, a clamping structure, the shape and size of which are matched with the outer shape of the light waveguide plate 110, so as to ensure that the light waveguide plate 110 can be tightly installed therein and faces outwardly to the installation cavity 221.

[0061] The first installation part 420 is arranged on the first side wall 402 below the top part 401, and the other side walls connected between the top part 401 and the first side wall 402 are arranged with at least one reflecting part 440. In some embodiments, the reflecting part 440 can be arranged on the other side walls except the first side wall 402, so that the light rays not projected to the light waveguide plate 110 by the light source 120 can be reflected to the light waveguide plate 110 as much as possible.

[0062] Specifically, in some embodiments, the first installation part 420 can be implemented as a groove, the shape and size of which are matched with the outer shape of the light source 120, so as to ensure that the light source 120 can be firmly installed therein. Optionally, the first installation part 420 is implemented as a mouth part. The light source 120 can be fixed in the first installation part 420 by screws, buckles or other mechanical fixing methods. Optionally, the first installation part 420 can also be implemented as a hole part. In the illustrated embodiment, the first installation part 420 is implemented as a slot matched with the light waveguide plate 110, so that the light source 120 can be tightly matched with the light waveguide plate 110, and the light waveguide plate 110 can be installed on the first installation part 420 in an embedded manner.

[0063] wherein, in Figure 1 In an example, the first mounting portion 420 is located on the first sidewall 402 of the optical cavity 410 and forms a certain angle of inclination with the optical waveguide plate 110. The angle of inclination should ensure that the light rays of the light emitting surface of the light source 120 can be projected onto the optical waveguide plate 110, and the angle of inclination determines the angle of the levitation imaging opposite medium imaging plate symmetrical to the light emitting surface, so the angle of inclination should be set to an angle convenient for users to view. In some embodiments, the plurality of light rays projected by the light emitting surface are parallel to each other. Since part of the projected light rays can not be directly projected onto the optical waveguide plate 110, at least one reflecting portion 440 is further provided in the optical cavity 410. The reflecting portion 440 can be a plane mirror or a curved mirror, and the shape and position thereof should ensure that the light rays can be reflected by the reflecting portion 440 to be projected onto the optical waveguide plate 110. The reflecting portion 440 can be mounted on the inner wall of the optical cavity 410 by adhesion, screws, or integral molding with the optical cavity 410.

[0064] Optionally, in Figure 1 In an example, in order to mount the mounting structure 400 in the mounting cavity 221, a support portion 510 is formed on the inner sidewall of the mounting cavity 221 and maintains a certain distance from the mounting opening. The support portion 510 is used to support the mounting structure 400 and forms a groove portion between the inner sidewall of the mounting cavity 221 and the support portion 510, so as to ensure that the mounting structure 400 is stably mounted in the mounting cavity 221. A supported portion 520 is formed on the surface of the mounting structure 400 and is arranged on the support portion 510. The supported portion 520 is used to cooperate with the support portion 510. The supported portion 520 can be a groove or a protruding portion formed on the surface of the mounting structure 400, and the shape and size thereof are matched with the support portion 510, so as to ensure that the mounting structure 400 can be stably mounted in the mounting cavity 221. Figure 1 In an example, the support portion 510 is a protruding edge. In other examples, the support portion 510 can also be a bracket, and the shape and size thereof are matched with the mounting structure 400, so as to ensure that the mounting structure 400 can be stably mounted thereon. Figure 2 In an example, a plurality of stepped reinforcing ribs 530 are further arranged between the support portion 510 and the mounting structure 400. The reinforcing ribs 530 are used to improve the strength and stability of the support portion 510. The reinforcing ribs 530 can be uniformly distributed or locally reinforced according to the stress condition. The position of the support portion 510 should ensure that the mounting structure 400 can be stably mounted in the mounting cavity 221 and maintain a proper distance from the optical waveguide plate 110, so as to prevent affecting the imaging of the optical waveguide plate 110.

[0065] Optionally, in Figure 1In an example, the installation opening is further provided with a light-transmissive plate 230 located outside the optical waveguide plate 110. The light-transmissive plate 230 is made of transparent optical material, such as acrylic or glass, and has good light-transmissive performance, while being capable of protecting the optical waveguide plate 110 from external environment. The light-transmissive plate 230 can effectively prevent dust, water vapor or other contaminants from entering the installation cavity 221, protecting the key components such as the optical waveguide plate 110 and the light source 120 from pollution, and prolonging the service life of the device. In Figure 1 In an example, the light-transmissive plate 230 covers the optical waveguide plate 110.

[0066] Optionally, the light-transmissive plate 230 is unidirectional light-transmissive from the inside to the outside of the installation cavity 221. That is, light can only pass through the light-transmissive plate 230 from the inside of the installation cavity 221 to the outside, while external light cannot enter the installation cavity 221 through the light-transmissive plate 230. The unidirectional light-transmissive design reduces the entry of external light into the optical cavity 410, preventing external light from being reflected by the reflecting portion 440 to the optical waveguide plate 110 and mixing with internal light, which may cause image details to be blurred and reduce the clarity of imaging. In addition, the unidirectional light-transmissive design makes the structure inside the installation cavity 221 invisible from the outside, improving the overall aesthetics.

[0067] Optionally, the installation cavity 221 includes a first installation area 2211 provided with the main body 100, and a second installation area 2212 connected to the first installation area 2211. Figure 1 In an example, the installation cavity 221 includes a first installation area 2211 provided with the main body 100, and a second installation area 2212 connected to the first installation area 2211.

[0068] The second installation area 2212 is provided with circuit components electrically connected to the main body 100.

[0069] In some embodiments, the first installation area 2211 is mainly used for installing the light source 120, while the second installation area 2212 is used for installing circuit components and other electronic components. This separation design makes the functional modules not interfere with each other.

[0070] By placing the light source 120 and the circuit components in two areas respectively, the space inside the housing 200 can be better utilized, making the overall structure of the device more compact. The first installation area 2211 is close to the optical waveguide plate 110, reducing the distance of light transmission and improving the efficiency of the optical path. The second installation area 2212 is away from the optical cavity 410, avoiding the influence of heat generated by electronic components on the optical system.

[0071] Optionally, the inner wall of the installation cavity 221 is provided with a wiring portion, and the wiring portion includes a wiring through hole 600 for passing an electrical connection line between the main body 100 and the circuit components. Optionally, the wiring through hole 600 is used to safely pass the electrical wire or cable between the light source 120 and the circuit components, avoiding direct exposure of the electrical wire or causing interference.

[0072] Optionally, the circuit components include a control panel exposed at the bottom of the housing 200. Although the control panel is not shown in the example, it should be included in the protection scope of the present disclosure. In the example, the control panel is located at the center of the wiring through hole 600. The control panel can control the on-off operation of the device, and the user can start or shut down the device through a simple button or touch operation. At the same time, the wiring of the wiring part is connected to the control panel to connect external devices through the socket on the control panel. Figure 3 Figure 3 In the example, the area for installing the control panel is located at the center of the wiring through hole 600. The control panel can control the on-off operation of the device, and the user can start or shut down the device through a simple button or touch operation. At the same time, the wiring of the wiring part is connected to the control panel to connect external devices through the socket on the control panel.

[0073] The above embodiments are only illustrative of the principles and effects of the present disclosure, and are not intended to limit the present disclosure. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present disclosure should be included in the protection scope of the present disclosure.​

Claims

1. A portable display device based on medium-free holographic projection, characterized in that, The application relates to a light source device, which comprises a main body, a shell, a support and an installation structure. The shell comprises a first shell and a second shell arranged in a double-layer mode; the first shell is a transparent part arranged on an outer layer, and the second shell is an opaque part arranged on an inner layer; the main body is arranged in a mounting cavity formed by the second shell. The support is arranged at the bottom of the second shell and is transparent. An installation opening is arranged at the top of the shell.

2. The portable display device of claim 1, wherein, The main body comprises a light waveguide plate arranged in the mounting cavity and corresponding to the installation opening, and a light source arranged in the mounting cavity. The light emitting surface of the light source forms an inclined angle with the surface of the light waveguide plate facing the mounting cavity, so as to form an aerial image of the light emitting pattern on the light source on the surface of the light waveguide plate away from the mounting cavity. The installation structure arranged in the mounting cavity comprises an optical cavity, and the inner wall of the optical cavity is provided with a first mounting part for arranging the light source, a second mounting part for arranging the light waveguide plate and at least one reflection part facing the second mounting part. The first mounting part is implemented as an installation opening or a slot; and / or the first mounting part is implemented as a slot matched with the light waveguide plate.

3. The portable display device of claim 2, wherein, The inner wall of the mounting cavity and the installation opening keep a certain distance, and the surface of the installation structure is provided with a supported part supported on the support part. An installation opening is arranged at the top of the shell, and the installation opening is provided with a light transmission plate.

4. The portable display device of claim 3, wherein, The light transmission plate is unidirectional light emission from the inner side to the outer side of the mounting cavity.

5. The portable display device of claim 3, wherein, The mounting cavity comprises a first installation area provided with the main body and a second installation area communicated with the first installation area.

6. The portable display device of claim 1, wherein, The second installation area is provided with circuit components electrically connected with the main body.

7. The portable display device of claim 6, wherein, The inner wall of the mounting cavity is provided with a wiring part, and the wiring part comprises a wiring through hole for arranging the electrically connected lines between the main body and the circuit components.

8. The portable display device of claim 1, wherein, The circuit components comprise a control panel exposed at the bottom of the shell. ​ 9. The portable display device of claim 8, wherein, ​ 10. The portable display device of claim 8, wherein, ​

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