Display assembly
By using a high-refractive-index transparent substrate and side-textured OLED display components in watches, the problems of low optical efficiency of digital displays and poor readability of passive displays are solved, achieving efficient light extraction and enhanced readability of passive displays.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- THE SWATCH GRP RES & DEVELONMENT LTD
- Filing Date
- 2018-07-12
- Publication Date
- 2026-06-23
AI Technical Summary
The optical efficiency of existing digital displays is low, especially organic light-emitting diode (OLED) devices, which are limited in their light extraction efficiency. Furthermore, passive displays are difficult to read in the dark. When traditional mechanical displays are combined with digital displays, there are problems with optical efficiency and readability.
An organic light-emitting diode display device on a transparent substrate is used. The light that is reflected by total internal reflection is extracted again to illuminate the secondary object by setting diffuse light on the side of the substrate. The light extraction is optimized by combining a high refractive index substrate and side texturing. It is then combined with a passive analog display in a watch.
It improves optical efficiency, enables readability of passive displays in watches, reduces power consumption, and enhances display quality, especially the illumination effect of the date display.
Smart Images
Figure CN115793428B_ABST
Abstract
Description
[0001] This application is a divisional application of patent application number 201810764665.8, which was filed on July 12, 2018, and was entitled "Display Assembly". Technical Field
[0002] The present invention relates to a display assembly, and more specifically, to an organic light-emitting diode (OLED) display assembly intended to illuminate a passive display device, such as in a clock or watch. Background Technology
[0003] In the watch industry, an increasing number of devices are combining traditional mechanical displays using hands with digital displays for applications such as smartphones or any other object with a communication mechanism.
[0004] In such devices, when the digital display is backlit, it is only turned on when needed to reduce system power consumption. However, mechanical display devices are purely passive and therefore cannot operate without power. In the case of a phosphorescent coating, it can be read in the dark. These phosphorescent coatings have not performed well enough in some applications (such as for date discs), not only because of the small surface area coated, but also because of the excessive thickness formed.
[0005] However, in existing digital displays, light is emitted forward and cannot illuminate other objects that are on the same plane or set slightly behind the front of the display.
[0006] Furthermore, the efficiency of known light-emitting diode (LED) devices, including those with organic active layers commonly used to illuminate these displays (OLED or DELo), is severely limited by optical efficiency due to the difficulty of extracting light from a high-refractive-index medium to a low-refractive-index medium. This inefficiency is primarily attributed to total internal reflection of light emitted from the active layer. In fact, unlike lasers where coherent light is highly oriented by the resonant cavity, light in LEDs is emitted isotropically. This isotropy results in light being emitted at an angle higher than the critical angle for total internal reflection with respect to the surface normal of the extracted light, thus trapping the light within its substrate. For unoptimized substrates, this trapped light can be as high as 80% of the emitted light.
[0007] To improve the optical efficiency of digital displays, various strategies have been proposed in the prior art for texturing the surface of the extract, such as surface roughening, optimizing the regular structure of the "optical" film used for light extraction, and a semi-cylindrical "dome structure" above the active region (pixel).
[0008] However, for dates, regardless of the extraction device, a non-negligible proportion of the light emitted at the LED junction remains intercepted and lost within the light guide device formed by the substrate, and, where appropriate, lost in the different layers constituting the OLED. Summary of the Invention
[0009] The present invention relates to a display assembly including an organic light-emitting diode display device (OLED), comprising at least one OLED and a secondary object to be illuminated, the at least one OLED being formed by a light-emitting stack structure disposed on a transparent (or semi-transparent or translucent) substrate, the back side of the substrate being disposed on the main light-emitting surface of the OLED display device, the substrate including a front side and at least one side side, the side side being arranged to illuminate the secondary object.
[0010] The display assembly is particularly suitable for integration into a watch, wherein a main surface forming the watch dial displays information conveyed to the user. This main surface may include integrated or added decorations and can be manufactured using various known techniques (pad printing, screen printing, digital printing, transfer printing, etc.). Secondary objects are arranged adjacent to the side surfaces and are illuminated when light intercepted between the front surfaces of the substrate exits through the side surfaces of the substrate. Typically, this recovered light can be advantageously used to illuminate a passive analog display arranged adjacent to the side surfaces. When an OLED display device forms a watch dial, through-holes can be provided in the thickness of the dial to form openings, and advantageously, the OLED display device can be combined with a passive analog display device of the date display type, wherein a date disc moves below the opening, and wherein the information carried by the date disc, seen through the opening, can be illuminated by light extracted from the sidewalls of the opening. The display device can also illuminate secondary objects arranged adjacent to the side surfaces and substantially coplanar with the substrate.
[0011] Preferably, the side surface is frosted to produce diffused light during use.
[0012] Advantageously, the side faces form an angle between 90° and 135° with the front faces.
[0013] Advantageously, the transparent substrate has a higher refractive index than the OLED layer, thereby confining light within the substrate.
[0014] Advantageously, an opaque cover is provided on the side of the secondary object that does not illuminate it. Attached Figure Description
[0015] Figure 1 A perspective view of a watch including a display assembly according to the present invention is shown;
[0016] Figure 2It shows Figure 1 The cross-sectional view shown is of a watch including a display assembly according to the present invention; and
[0017] Figure 3 It shows Figure 2 A magnified view of area 10. Detailed Implementation
[0018] The object of the present invention is to provide a display assembly comprising an organic light-emitting diode (OLED) display device A for displaying information required by a user and a secondary object 6 to be illuminated, which enables optimal use of light emitted by one or more OLEDs of the OLED display device A, which is intercepted and recaptured between the surfaces of the substrate of the device to illuminate the secondary object 6 associated with the OLED device.
[0019] Figure 1-3 An embodiment of the invention is shown, illustrating a watch M that combines a hybrid display device including an active light-emitting screen A (backlit, LED, or OLED) and a passive display, the active light-emitting screen being decorated on its surface facing the user, and the passive display including a time dial cooperating with hands 11 and a passive display element 6 visible through an opening 7 provided in the time dial.
[0020] like Figure 3 As shown, the display assembly of the present invention utilizes light intercepted by total internal reflection in the transparent layer 2 of the active display by extracting light via a side surface 8 substantially perpendicular to the main surface or at an angle α between 90° and 135° relative to the front surface. The active display device of the present invention includes an OLED-type light-emitting layer 1 disposed on the back side of the transparent substrate 2. The OLED-type light-emitting layer may be an active-matrix OLED screen or a liquid crystal display (LCD) of the TFT type, particularly associated with a backlight device including OLEDs or LEDs. In the latter case, light is re-acquired from the side of the light guide of the backlight device. In this specification, the screen is considered the main display.
[0021] In such a device, only light emitted by the OLED at an angle less than the critical angle to the normal of the curved surface of the display glass can emerge from the front of the transparent substrate.
[0022] According to the invention, the portion of light 5 that is intercepted between the parallel planes of the transparent substrate 2 due to total internal reflection is extracted via at least one side 8 formed in the selected area. This light can then be used to illuminate other elements 6, referred to as secondary elements, such as analog time displays or display components visible through the opening 7, such as a date disc 6.
[0023] The ratio of light emitted from the front of the substrate to light emitted from its edges or sides can be altered by changing the refractive index of the substrate; the higher the refractive index of the substrate, the more light will be trapped in the transparent layer 2. In this respect, it may be advantageous to use a high refractive index substrate 2, such as sapphire with a refractive index of 1.768.
[0024] One or more additional layers 3 may be added to the surface of the transparent substrate 2. These layers may serve, for example, as scratch-resistant layers, anti-reflective layers, or decorative layers.
[0025] The side surfaces 8 of the substrate 2 preferably have a texture that reduces internal reflection to optimize light extraction. In particular, water jetting, abrasive grinding, or ultrasonic cutting techniques have a beneficial desmoothing effect in roughening the side surfaces 8 of the substrate 2, thereby improving diffusion and thus the uniformity of light extraction.
[0026] Depending on the position of the secondary object 6 to be illuminated, it may be advantageous to tilt the illumination side 8. Specifically, as... Figure 1 As shown, it is set slightly recessed relative to the main display, similar to a traditional mechanically driven date disc (see...). Figure 2 and 3 The object is preferably illuminated by the side oriented toward the secondary display, which has the additional advantage of reducing direct eye contact and thus reducing glare.
[0027] To prevent unwanted lighting, the sides not intended for illuminating secondary objects can be advantageously covered with an opaque, preferably reflective, layer 9.
[0028] like Figure 2 and 3 As shown, the organic light-emitting diode (OLED) display device of the present invention is advantageously integrated into a hybrid watch that includes a conventional time display comprising hands 11 and an opening 7, below which a date disc 6 is driven. In this configuration, the hands are illuminated from behind by the main OLED display forming the dial behind them, while the opening 7 is illuminated by the side 8 of the opening 7 disposed in the substrate 2 of the OLED display device of the present invention.
Claims
1. A display assembly including an organic light-emitting diode (OLED) display device, the display assembly comprising at least one OLED display device (1) and a secondary object to be illuminated, the at least one OLED display device comprising a light-emitting stack structure disposed on a transparent, semi-transparent, or translucent substrate (2), the back side of the substrate (2) being disposed on the light-emitting surface of the OLED display device (1), the transparent substrate comprising a front side and at least one side side (8), the at least one side side being arranged to illuminate the secondary object (6), wherein, A reflective layer (9) is provided on a side that does not provide illumination for the secondary object (6) and is different from the at least one side (8); and wherein the reflective layer (9) is formed perpendicular to the main light-emitting surface of the organic light-emitting diode display device (1) so that light emitted from the main light-emitting surface and subsequently intercepted in the substrate (2) by reflection from the substrate (2) is emitted from the at least one side (8).
2. The display assembly according to claim 1, characterized in that, The display component includes an analog time display.
3. The display assembly according to claim 2, characterized in that, The secondary object (6) includes a simulated time disk.
4. The display assembly according to any one of the preceding claims, characterized in that, The secondary object (6) is arranged in the watch opening.
5. The display assembly according to any one of the preceding claims, characterized in that, The side surface (8) is roughened to produce diffuse light during use.
6. The display assembly according to any one of the preceding claims, characterized in that, The side (8) forms an angle between 90° and 135° with the front.
7. The display assembly according to any one of the preceding claims, characterized in that, The transparent substrate (2) has a refractive index of at least 1.
5.
8. The display assembly according to claim 7, characterized in that, The transparent substrate (2) has a refractive index between 1.6 and 1.
8.
9. The display assembly according to any one of the preceding claims, characterized in that, The front of the base includes integrated or additional decorative elements.
10. The display assembly according to any one of claims 1-8, characterized in that, The substrate is mounted below the semi-transparent dial.
11. A watch comprising a display assembly according to any one of the preceding claims.