Patent Application
20230078131
This application claims priority to Chinese Patent Application No. 202111087167.2 filed Sep. 16, 2021, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure relates to the field of display technology, and in particular to a display device and a manufacturing method thereof.
Organic light emitting diodes (OLEDs) are considered to be the most promising new generation display technology because of their excellent characteristics such as self-luminescence, low energy consumption, wide viewing angle, rich color, rapid response and applicability for preparation of flexible display screen. As a new human-computer interaction mode in the field of intelligent wearing, the intelligent wearing provides exclusive, personalized services for consumers through intelligent apparatuses being worn on a human body. With the development of mobile internet technology and the maturity of core hardware technologies of wearable apparatuses, such as low-power chips and flexible circuit boards, some wearable apparatuses have gradually developed from conceptualization to commercialization.
Among those wearable apparatuses, augmented reality (AR) glasses and virtual reality (VR) glasses are relatively common intelligent wearable apparatuses currently. In the practical application of AR glasses and VR glasses, in one aspect, the device is required to be small in size, light in weight and compact in package in order to be portable. However, in another aspect, people unremittingly pursue graphic information with high brightness, high precision and rich color, three-dimensional image, and video image with a high refresh rate, all of which cause increase of power consumption per unit volume, and consequently the heat emitting issue becomes more serious. The heat generated by the system cannot be rapidly dissipated outward, and is apt to accumulate on the skin surface of the user. Since the skin surface is in direct contact with the apparatus, the user experience is adversely affected. From the user's feeling, a hot temperature felt by a hand is about 50 degrees Celsius. However, an apparatus worn on a person's face or head may cause the user to feel extremely discomfort if its temperature is near or slightly over 40 degrees Celsius. In extreme working environments, such as outdoor applications in summer, the heat emitting issue may cause rapid declination of the performance of organic light emitting film of an OLED display screen, system crash, and even burn of temperature-sensitive parts.
Currently, the issue of heat dissipation difficulty is common for intelligent wearable apparatuses, and becomes the bottleneck of product use. In addition, the heat dissipation will be getting more and more serious with the improvement of high integration and image resolution. Accordingly, a technical issue to be addressed by the person skilled in the art urgently is that the existing intelligent wearable apparatuses can not dissipate heat in time.
The present disclosure relates to a display device capable of dissipating heat rapidly. The display device includes a thermally conductive housing, an optical lens, a micro-display screen and a liquid. The optical lens, the micro-display screen and the liquid are packaged in the thermally conductive housing. The liquid is transparent and thermally conductive and mixed with a dispersant and nanoparticles, and lights emitted from the micro-display screen reach the optical lens via the thermally conductive liquid. In some examples, the thermally conductive liquid is embodied as a mixed solution of deionized water and ethylene glycol or is embodied as a silicone oil. In a particular embodiment, each of the nanoparticles is less than 100 nanometer (nm) in any dimension for further enhancing the thermally conductive property. These nanoparticles may be made of a metal such as gold, silver, or aluminum, or may be made of a metal oxide such as titanium oxide.
In some examples, the display device may include an aperture that also has the thermally conductive property, which aperture is embodied as a conic-shaped funnel structure to define a maximum divergence angle of lights and improve uniformity of the edge of the output beam. In a particular embodiment, the aperture and the thermally conductive housing may be made of a same metal material, and a black plating layer or a layer of low reflection film formed by anodizing or the like is provided on each light incident surface to reduce adverse effects of light reflection on the output image. In a particular embodiment, an inner sidewall of the aperture is a wetting surface, and the surface is provided with multiple groove structures or is roughened. In this way, not only air bubbles can be prevented from adhering, but also the contact area between the aperture and the thermally conductive liquid can be increased, thereby improving the heat exchange efficiency between the aperture and the thermally conductive liquid.
The present disclosure further provides, in a process of manufacturing the high-efficient heat-dissipating display device according to the present disclosure, a method of filling a thermally conductive liquid into a container and a packaging method, such as preforming an injection hole and an overflow hole in a container wall, and optimizing measures such as an ambient temperature under which the injecting and packaging are performed is higher than a skin temperature of a human body. These methods of filling the thermally conductive liquid and packaging are intended to ensure that leakage of the thermally conductive liquid does not occur and no bubbles and voids are generated in the container during later use, especially when the ambient temperature changes substantially.
The drawings herein is incorporated into the specification and forms part of this specification, shows an embodiment conforming to the present disclosure, and is used together with the specification to explain the principles of the present disclosure. Apparently, the drawings in the following description is only some embodiments of the present disclosure, and for those having ordinary skill in the art, other drawings can be obtained from these drawings without creative efforts.
Hereinafter exemplary embodiments are further described in detail in conjunction with the drawings. However, exemplary embodiments may be implemented in many forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments/implementations enables the present disclosure to be comprehensive and complete, and fully communicate the concept of the exemplary embodiments/implementations to those skilled in the art. The same reference numeral in the figure denotes the same or similar structure, therefore, the descriptions thereof will not be repeated.
Referring to
Specifically, the barrel-shaped container 1 is made of metal, ceramic, plastic or other thermally conductive materials, and the thermal conductivity of each of the metal, ceramic, plastic and other thermally conductive materials is required to be higher than the thermal conductivity of the liquid 2. In this way, the liquid 2 may conduct heat to the barrel-shaped container 1. In this embodiment, the barrel-shaped container 1 is a cylindrical container (i.e., a circular cylinder). Referring to
The liquid 2 is required to have a good thermally conductive performance and a high transparency to visible light. The thermal motion of the liquid molecules of the liquid 2 will be accelerated after the liquid 2 is heated, and the thermally conductive ability of the liquid 2 is far better than that of other media such as gas and plastic. Therefore, the liquid 2 is sealed in the barrel-shaped container 1, which enables the heat inside the container to be rapidly transferred to the housing of the barrel-shaped container 1, and then emitted to the ambient air to realize rapid heat dissipation.
In this embodiment, the liquid 2 further includes a mixed solution with deionized water and ethylene glycol. Specifically, the ethylene glycol has anti-freezing and anti-corrosion effects, and the volume ratio of the ethylene glycol in the mixed liquid is generally within a range from 20% to 40%. In a case where a mixed solution with deionized water and ethylene glycol is used as the liquid 2, the liquid 2 will not condense even in minus30 degrees Celsius (° C.) outdoors. In another embodiment, the main component of the liquid 2 is a silicone oil. The silicone oil has a thermal conductivity of 2 W/mK or higher, a freezing point as low as minus 50° C. , and a gasification point above 100° C. The silicone oil more suitably serves as the liquid 2 of the display device 10 than pure water having a thermal conductivity of about 0.6 W/mK.
In other embodiments, the liquid 2 may also be mixed with a proportion of dispersant and nanoparticles to further improve thermal conductivity and visible light transmittance. Specifically, each of the nanoparticles is less than 100 nanometer (nm) in any dimension. The nanoparticles include the nanorods (rod-shaped nanoparticles) that a ratio between an average diameter of the nanorods and an average length of the nanorods is less than 0.75. The nanorods are also referred to as nanowires, and have a length being less than 100 nm. The nanoparticles are made of a metal or metal oxide, the metal may be selected from gold, silver, copper or aluminum, and the metal oxide may be selected from titanium dioxide, aluminum oxide or copper oxide. The dispersant, such as citrate, will negatively charge the surface of the nanostructures in solution, thereby allowing the nanoparticles to repel each other without aggregating into larger particles and allowing visible lights having a wavelength ranging from 400 nm to 760 nm to pass through the liquid 2. The liquid 2 uniformly mixed with nanoparticles has a higher thermal conductivity (10 times or more) than the liquid 2 not mixed with nanostructures, and a visible light transmittance reaching 95% or more.
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In this embodiment, the aperture structure 5 is made of a metal material, or a non-metal material such as a resin or rubber doped with carbon powder. For example, the non-metal material may include a black conductive rubber or a black conductive resin. In one embodiment, the aperture structure 5 is made of metallic copper or metallic aluminum, so that the aperture structure 5 is ensured to have a high thermal conductivity.
In this embodiment, the fuel structure of the aperture structure 5 has a smooth inner sidewall, and the inner sidewall of the fuel structure has a wetting surface for the liquid 2. When liquid 2 is injected into the aperture structure 5, the liquid 2 is in close contact with the inner sidewall of the aperture structure 5, or in a wetting state in which the contact angle is less than 90 degrees. In a case where the inner sidewall is a wetting surface for the liquid 2, the liquid 2 fills all the gaps and fine potholes, and expels bubbles which may adhere to these places.
In order to further increase the heat exchange efficiency between the aperture structure 5 and the liquid 2, the inner sidewall of the aperture structure 5 may further be processed to increase the contact area between the aperture structure 5 and the liquid 2. Referring to
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In one embodiment, the electronic display screen 4 is a waterproof component and may be in direct contact with the liquid 2. The transparent protection layer 42 in the electronic display screen 4 may be a transparent protective film layer formed directly on the light emitting area 41, or may be a transparent cover plate disposed opposite to the light emitting area 41 and fixedly connected to the light emitting area 41.
In this embodiment, the electronic display screen 4 is embedded in an opening at the bottom of the barrel-shaped container 1, and the bottom of the electronic display screen 4 (i.e., a side facing away from the optical lens 3) is exposed outside, and signal wires and control wires of the electronic display screen 4 are directly led out from the bottom of the electronic display screen 4. In order to ensure that the transparent protection layer 42 of the electronic display screen 4 (i.e., a side facing the optical lens 3) is in sufficient contact with the liquid 2, the surface of the transparent protection layer 42 is required to be flush with or higher than an inner surface of the bottom of the barrel-shaped container 1.
In other embodiments, the electronic display screen 4 is directly fixed to the bottom of the barrel-shaped container 1, and the electronic display screen 4 is immersed in the liquid 2. For this purpose, the barrel-shaped container 1 is required be provided with a wire through hole, and the signal wires and control wires of the electronic display screen 4 are led out through the wire through hole provided in the barrel-shaped container 1.
In this embodiment, the size of the electronic display screen 4 is required to be smaller than the minimum hole diameter being the aperture structure 5 to ensure the integrity of the image display. The optical axis of the optical lens 3 perpendicularly passes through the center of the light emitting area 41 of the electronic display screen 4. In one embodiment, the centers of the electronic display screen 4, the aperture structure 5, and the optical lens 3 are each located in line with the central axis of the barrel-shaped container 1.
In this embodiment, the optical lens 3 is a convex lens, and at least one surface of the convex lens is a curved surface projecting outward (i.e., a convex surface). For example, the convex lens has two convex surfaces opposite to each other; alternatively, one surface of the convex lens is a convex surface, and the other surface may be a flat surface or a concave surface.
In this embodiment, the electronic display screen 4 is a silicon-based organic light emitting display screen, and the silicon-based organic light emitting display screen is a silicon-based micro-display screen (Si based Microdisplay) adopting an organic light emitting display technology. Among differentiators against the conventional OLED display component using amorphous silicon, microcrystalline silicon or low-temperature polysilicon thin-film transistor as a backboard, the Si based Microdisplay is an active OLED display component made by taking single crystal silicon as an active driving backboard, and has a pixel size of about 1/10 of the conventional display component, a fineness much higher than that of the conventional display component, and has many advantages such as high resolution, high integration, low power consumption, small volume, light weight. In other embodiments, the electronic display screen 4 may be another type of micro display screen, which is not limited by the present disclosure, as long as the displayed optical image can meet the requirements.
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If the temperature of the display device 10 changes drastically during use, it may cause voids to be left inside the barrel-shaped container 1, thereby causing air bubbles. The air bubbles may cause refraction and reflection of the lights emitted from the electronic display screen 4, which adversely affects the display effect. For this reason, the materials of the barrel-shaped container 1 and the aperture structure 5 should be properly selected to minimize the difference in thermal expansion coefficient between the barrel-shaped container 1 and the aperture structure 5.
In one embodiment, the barrel-shaped container 1 and the aperture structure 5 are made of the same metal material. In such way, not only the difference in the thermal expansion coefficient between the barrel-shaped container 1 and the aperture structure 5 may be reduced, and the generation of air bubbles can be avoided, but also the phenomenon of electrolysis of different metals in a liquid having a certain conductivity and the electrochemical corrosion caused thereby may be prevented.
Accordingly, manufacturing methods of a display device are further provided according to the present disclosure. Referring to
In a step 1, a barrel-shaped container 1 with an overflow hole 1a is provided, and an electronic display screen 4 is mounted at a bottom of the barrel-shaped container 1.
In a step 2, a funnel-shaped aperture structure 5 is tightly fitted into the cavity of the barrel-shaped container 1.
In a step 3, a transparent and thermally conductive liquid 2 is injected into the barrel-shaped container 1.
In a step 4, an optical lens 3 is mounted on the aperture structure 5 and an optical axis of the optical lens 3 is kept perpendicular to a light emitting area of the electronic display screen 4, and excess liquid and air is discharged through an overflow hole 1a of the barrel-shaped container 1.
In a step 5, a gap between the optical lens 3 and the barrel-shaped container 1 is sealed with a sealant 6, and the overflow hole 1a is sealed with the sealant 6.
Specifically, first, a barrel-shaped container 1 with an overflow hole is provided, and an electronic display screen 4 is mounted at the bottom of the barrel-shaped container 1.
In this embodiment, a mounting hole is provided in the bottom of the barrel-shaped container 1, and the electronic display screen 4 is mounted in the mounting hole. In order to ensure the air tightness of the barrel-shaped container 1, the gap between the barrel-shaped container 1 and the electronic display screen 4 is sealed by a sealant. The sealant after being cured may prevent liquid leakage and air entering. Therefore, the process of mounting an electronic display screen 4 at the bottom of the barrel-shaped container 1 includes: first, fitting the electronic display screen 4 into the hole in the bottom of the barrel-shaped container 1 and configuring the surface of the transparent protection layer 42 of the electronic display screen 4 to be flush with or higher than the inner surface of bottom of the barrel-shaped container 1; using a sealant to seal the gap between the electronic display screen 4 and the barrel-shaped container 1; and then, curing the sealant.
In other embodiments, the bottom of the barrel-shaped container 1 may not be provided with the mounting hole, and the electronic display screen 4 is directly mounted on the inner surface of the bottom of the barrel-shaped container 1. However, in this case, a wire through hole is required to be provided in the barrel-shaped container 1, and the signal wires and control wires of the electronic display screen 4 are led out through the wire through hole.
In this embodiment, at least one overflow hole 1a is provided at the sidewall of the barrel-shaped container 1, and the overflow hole 1a is configured to discharge air or part of the liquid that overflows during assembling of the display device 10.
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It is to be noted that all of the above manufacturing processes may be performed in an environment with air or in an enclosed space having a certain degree of vacuum. In a case where the display component is manufactured in a vacuum environment, air may be further prevented from being trapped inside the barrel-shaped container 1 and the liquid 2, and air may be prevented from precipitating from the inner wall of the container or the liquid and turning into bubbles, thus, no bubbles may be generated even when the temperature changes or the orientation of the container changes, such as in inversion or vibration.
It is to be noted that in the packaging process from the step 3 to the step 5, the barrel-shaped container 1 and the liquid 2 should be kept in a constant temperature state, and the temperature in the packaging process is required to be between 36 degrees Celsius and 60 degrees Celsius. In this way, as long as the operating temperature of the display device 10 is lower or slightly higher than this packaging temperature, generally no air bubbles will be presented in the barrel-shaped container 1.
Referring to
Specifically, this embodiment differs from the first embodiment in that the barrel-shaped container 1 is not a circular barrel-shaped container, but a rectangular barrel-shaped container. The rectangular barrel-shaped container includes a rectangular bottom plate and four rectangular side plates arranged to surround the outer periphery of the rectangular bottom plate, the four side plates are sequentially connected end to end and arranged perpendicular to the rectangular bottom plate, and the four rectangular side plates are integrally formed with the rectangular bottom plate. Compared with the circular barrel-shaped container, the rectangular barrel has a larger margin for drum deformation caused by cold shrinkage than that provided by the circular barrel when the use temperature is lower than the packaging temperature.
In one embodiment, the rectangular bottom plate has a thickness larger than the thickness of the rectangular side plates. That is, the thickness of the sidewalls of the barrel-shaped container is smaller than the thickness of the bottom housing thereof. Thus, when the temperature changes, the barrel-shaped container 1 is deformed mainly in sidewalls, and not in the bottom thereof, thereby ensuring that the electronic display screen 4 adjacent to the bottom of the container is not adversely affected accordingly.
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In this embodiment, the heat generated by the electronic display screen 4 may be rapidly conducted to the barrel-shaped container 1 and the aperture structure 5 through the liquid 2 and finally dissipated to the external environment, but also. In addition, the heat generated by the electronic display screen 4 may be dissipated through the PCB 7 and the metal connectors 8 supplementally, so that the efficiency of heat conduction is further improved.
In one embodiment, the barrel-shaped container 1, the PCB 7, and the metal connectors 8 are all connected to a constant potential, such as a ground potential, to shield ambient electromagnetic interference, thereby ensuring normal display of the electronic display screen 4.
In the display device according to the present disclosure, the optical lens 3 and the electronic display screen 4 are packaged in the barrel-shaped container 1 to form an integrated structure, and the liquid 2 is injected in the integrated structure. The liquid 2 cooperates with the barrel-shaped container 1 to rapidly discharge heat generated by the electronic display screen 4, thereby improving the service life and the use safety of the display device. The integrated structure may also be combined with other optical components to form AR glasses, VR glasses, or other intelligent wearable apparatuses. The inventors found that heat generation is most concentrated in the high-speed digital image processing chip and OLEDs having high-resolution and high-brightness in the entire system of AR glasses or VR glasses. Those components together with their surrounding components and packaging housing will all heat up rapidly after the system runs shortly. When the display device provided by the present disclosure is applied to the AR glasses or the VR glasses, the heat dissipation issues of these intelligent wearable apparatuses may be effectively addressed.
Referring to
The optical image displayed on the electronic display screen 4 generally includes lights of three basic colors: red (R), green (G), and blue (B). The lights after passing through the optical lens 3 become almost parallel lights, and those parallel lights are then reflected by the first mirror 11 into transversely propagating light beams. These transversely propagating light beams travel within the lens barrel for a certain distance and then reach the second mirror 12 and are reflected by the second mirror 12 into longitudinally propagating light beams. These longitudinally propagating light beams enter the human eye directly or are focused by the optical lens 13 and then reach the human eye 14.
In this embodiment, the optical lens 3 functions as an objective lens, and the other optical lens 13 functions as an eyepiece lens. The objective lens is a convex lens, and the eyepiece lens is a concave lens.
The above figures simply schematically show the display device according to the present disclosure. For the sake of clarity, the shapes and the numbers of the elements in the above figures are simplified, and some elements are omitted, variations may be made by a person skilled in the art according to practical requirements, and these variations are all within the protection scope of the present disclosure, and are not described herein again.
It is to be noted that the various embodiments in this specification are described in a progressive manner. Each of the embodiments is mainly focused on describing its differences from other embodiments, and references may be made among these embodiments with respect to the same or similar portions among these embodiments. The manufacturing method of the display device 20 is similar to that of the display device 10, and details are not described herein.
In summary, according to the display device and the manufacturing method thereof provided by the present disclosure, the optical lens and the electronic display screen are provided in the barrel-shaped container to form an integrated structure, and the thermally conductive liquid is injected into the integrated structure to realize rapid heat dissipation, thereby improving the service life and the use safety of the display device. The display device not only is compact in structure, but also may timely discharge heat generated by the electronic display screen, and is therefore more suitable for intelligent wearable apparatuses.
The above is a further detailed description of the present disclosure with reference to the preferred embodiment/implementation, and it is not assumed that the specific implementation of the present disclosure is limited to these descriptions. For a person of ordinary skill in the art to which the present disclosure pertains, a number of simple deductions or substitutions may be made without departing from the concept of the present disclosure, all of the deductions or substitutions should be deemed as falling within the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202111087167.2 | Sep 2021 | CN | national |
