TW202526459A - Display device - Google Patents

Abstract

A display device includes a display panel and a transparent cover. The display panel includes a plurality of pixel elements arranged in an array. Each pixel element includes a micro light-emitting diode, a reflective material, a first refractive material and a second refractive material. The reflective material is provided with a groove and an upper surface of the micro light-emitting diode is exposed in the groove . The first refractive material is in the groove and covers the micro light-emitting diode. The second refractive material is in the groove and covers the first refractive material. The interface between the first refractive material and the second refractive material is a curved surface. The transparent cover covers the display substrate, and a third refractive area is formed between the transparent cover and the second refractive material. The light emission of the display device in the first direction and the second direction is asymmetrical.

Description

Display device

The present disclosure relates to the field of display, and more particularly to a display device with asymmetric light output angles.

In the display industry, light-emitting diodes (LEDs) are gradually replacing backlight modules due to their advantages, such as high brightness and compact size. However, LED lighting components also come with specific problems in certain products.

For example, currently, LEDs are point light sources that typically emit light evenly in all directions. However, when used in automotive displays, such as head-up displays, the wide-angle light emitted by them can obstruct the driver's forward vision and affect driving safety.

The present disclosure provides a display device. In some embodiments, the display device includes a display substrate and a transparent cover. The display substrate includes a plurality of pixel elements arranged in an array. Each pixel element has a first side and a second side, and the first side is longer than the second side.

Each pixel element includes a micro-LED (micro-light-emitting diode), a reflective material, a first refractive material, and a second refractive material. The reflective material is located on the display substrate and has a groove formed therein. The upper surface of the micro-LED is exposed in the groove. The first refractive material is located in the groove and covers the upper surface of the micro-LED. The second refractive material is located in the groove and covers the first refractive material. The interface between the first and second refractive materials is a curved surface. The groove has a central axis, and the depth of the groove decreases with distance from the central axis. The central axis is parallel to the first direction. A transparent cover covers the display substrate, and a third refractive region is formed between the transparent cover and the second refractive material.

The refractive index of the second refractive material is greater than that of the first refractive material, and the difference between the first refractive material and the second refractive material is 0.3 to 0.6. The light emission of the display device in a first direction and a second direction perpendicular to the first direction is asymmetric.

In some embodiments, the width of the groove decreases from the first surface of the reflective material toward the micro-luminescent diode. More specifically, in some embodiments, the groove is parabolic from the first surface of the reflective material toward the edge of the micro-luminescent diode.

In some embodiments, the boundary between the first refractive material and the second refractive material is a hyperbola, a parabola, an ellipse, or a sphere.

In some embodiments, the first refractive material has a refractive index of 1.4 to 1.7.

In some embodiments, the refractive index of the second refractive material is 1.4 to 2.0. More specifically, in some embodiments, the refractive index of the second refractive material is 1.8 to 1.95.

In some embodiments, the third refractive region is a cavity.

In some embodiments, the third refractive region is filled with a third refractive material having a refractive index lower than that of the second refractive material. More specifically, in some embodiments, the refractive index of the third refractive material is 1.2 to 1.6.

More specifically, in some embodiments, the top surface of the third refractive material is coplanar with the first surface of the reflective material.

In some embodiments, the maximum half-width angle of the light intensity distribution in the second direction is less than or equal to +/- 20 degrees.

More specifically, in some embodiments, the half-width angle of the light intensity distribution in the first direction is greater than or equal to +/- 40 degrees.

In some embodiments, each pixel element has a first side and a second side, and the length of the first side is greater than that of the second side. The first side is parallel to the first direction, and the second side is parallel to the second direction.

In some embodiments, a length of a vertical projection of the groove on the transparent cover in the first direction is greater than a length in the second direction.

As shown in the aforementioned embodiments, by utilizing anisotropic grooves and combining the first refractive material and the second refractive index, the light output of the display device in the first direction and the second direction can be asymmetric, which can be applied to electronic devices that require a narrow viewing angle in a specific direction.

It should be understood that when an element is referred to as being "disposed" on another element, it can mean that the element is directly located on the other element, or that an intervening element is present, connecting the element to the other element. Conversely, when an element is referred to as being "directly disposed on" or "directly disposed to" another element, it should be understood that this clearly defines the absence of intervening elements.

In addition, the terms "first," "second," and "third" are used only to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part, and do not necessarily indicate a sequence of precedence or sequence. Furthermore, relative terms such as "lower" and "upper" may be used herein to describe the relationship of one element to another, and it should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if a device in an accompanying figure is turned over, an element described as being on the "lower" side of other elements would be oriented on the "upper" side of the other elements. This only indicates a relative orientation relationship, not an absolute orientation relationship.

Figure 1 is a perspective view of an embodiment of a display device. As shown in Figure 1 , in some embodiments, the display device 1 includes a display substrate 10 and a transparent cover 20. The display substrate 10 includes a plurality of pixel elements 30 arranged in an array. In other words, the pixel elements 30 have a rectangular shape. The transparent cover 20 covers the display substrate 10. In some embodiments, each pixel element 30 has a first side 301 and a second side 303, with the first side 301 being longer than the second side 303.

FIG2 is a cross-sectional view of a first embodiment of a pixel element. Referring also to FIG1 , FIG2 is a cross-sectional view of FIG1 taken along a second direction D2 (here, the Y direction) and a third direction D3 (here, the Z direction). Referring also to FIG1 , as shown in FIG1 and FIG2 , each pixel element 30 includes a micro-LED 31, a reflective material 33, a first refractive material 35, and a second refractive material 37. The micro-LED 31 is disposed on the substrate 11 through the conductive material 15. The micro-LED 31, the conductive material 15, and the substrate 11 are part of the display substrate 10. Furthermore, in the pixel element 30, the reflective material 33 is located on the micro-LED 31. Although only a partial cross-section is shown here, it is understood that the reflective material 33 covers the display substrate 10 in a layer. The reflective material 33 also defines a groove 331. Reflective material 33 covers the upper surface of substrate 11, conductive material 15, and a portion of micro-LED 31. The upper surface of micro-LED 31 is exposed in groove 331. Groove 331 has a central axis C. The depth of groove 331 decreases as it moves away from central axis C. Central axis C is parallel to first direction D1.

Here, the length of the groove 331 in the first direction D1 (here, the X direction) perpendicular to the transparent cover 20 is greater than the length in the second direction D2. The first direction D1 is parallel to the first side 301, and the second direction D2 is parallel to the second side 303.

A first refractive material 35 is located in the groove 331 and covers the upper surface of the micro-LED 31. A second refractive material 37 is located in the groove 331 and covers the first refractive material 35. The boundary S between the first and second refractive materials 35 and 37 is a curved surface. Furthermore, a third refractive region 38 is formed between the transparent cover 20 and the second refractive material 37.

Here, the refractive index of the second refractive material 37 is 1.4 to 2.0, greater than that of the first refractive material 35, and the difference between the first and second refractive materials 35 and 37 is 0.3 to 0.6. In some embodiments, the refractive index of the first refractive material 35 can be 1.4 to 1.7, while the refractive index of the second refractive material 37 can be 1.8 to 1.95. In the embodiment shown in FIG2 , the center of the third refractive region 38 is a cavity, that is, the third refractive region 38 contains only air, and the refractive index in the third refractive region 38 is approximately 1. This results in asymmetric light output from the display device 1 in the first direction D1 and the second direction D2. Furthermore, the display device can be applied to electronic devices that require a narrow viewing angle in a specific direction, such as automotive projection displays.

Figure 3A shows the light intensity distribution over angle for an embodiment of a display device. Figure 3B shows a light intensity mapping diagram for an embodiment of a display device. The maximum half-width angle (HWH) of the light intensity distribution in the second direction D2 is less than or equal to +/-20 degrees, and is approximately +/-17 degrees in this case. Meanwhile, the half-width angle (HWH) of the light intensity distribution in the first direction D1 is greater than or equal to +/-40 degrees. In other words, the second direction D2 (i.e., the Y direction) exhibits a narrow viewing angle.

By creating asymmetric light output through refraction, a narrower viewing angle can be achieved in specific directions. For example, when used in automotive head-up displays, this technology can provide relevant display functions while also avoiding interference with the driver's field of view, thereby ensuring driving safety. It can also be applied to electronic devices requiring a narrow viewing angle for privacy protection, anti-peeping, and other purposes.

Figure 4 is a cross-sectional view of a second embodiment of a pixel element. Referring also to Figure 2 , the main difference between the second embodiment and the first embodiment lies in the inclusion of a third refractive material 39 in the third refractive region 38. The refractive index of the third refractive material 39 is lower than that of the second refractive material 37. In some embodiments, the refractive index of the third refractive material 39 is between 1.2 and 1.6, for example, 1.5. Furthermore, in some embodiments, the top surface 391 of the third refractive material 39 is coplanar with the first surface 333 of the reflective material 33. In other words, the third refractive material 39 may not completely fill the third refractive region 38, allowing the refractive index of the third refractive material 39 to be adjusted with that of air.

2 and 4 , in some embodiments, the width of the groove 331 decreases from the first surface 333 of the reflective material 33 toward the micro-LED 31. More specifically, in some embodiments, the groove 331 is parabolic from the first surface 333 of the reflective material 33 toward the edge of the micro-LED 31.

Figure 5 is a cross-sectional view of a third embodiment of a pixel element. Figure 6 is a cross-sectional view of a fourth embodiment of a pixel element. Figure 7 is a cross-sectional view of a fifth embodiment of a pixel element. Figure 8 is a cross-sectional view of a sixth embodiment of a pixel element. As shown in Figures 5 to 8, and with reference to Figures 2 and 4, the interface between the first refractive material 35 and the second refractive material 37 is a curved surface. Preferably, the curved surface can be a hyperboloid as shown in Figures 2 and 4, a parabola as shown in Figure 5, a transverse elliptical surface as shown in Figure 6, a spherical surface as shown in Figure 7, or a vertical elliptical surface as shown in Figure 8.

In summary, in some embodiments, by utilizing asymmetric grooves 331 in each pixel element 30 and combining the first refractive material 35 and the second refractive material 37, the display device 1 can emit light asymmetricly in the first direction D1 and the second direction D2, thereby enabling application in electronic devices requiring a narrow viewing angle in a specific direction.

Although the technical contents of this disclosure have been disclosed above with reference to preferred embodiments, they are not intended to limit this disclosure. Any modifications and improvements made by persons skilled in the art without departing from the spirit of this disclosure should be included within the scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the scope of the attached patent application.

1: Display device 10: Display substrate 11: Substrate 15: Conductive material 20: Transparent cover 30: Pixel element 301: First side 303: Second side 31: Micro-LED 33: Reflective material 331: Groove 333: First surface 35: First refractive material 37: Second refractive material 38: Third refractive region 39: Third refractive material 391: Top surface C: Center axis D1: First direction D2: Second direction D3: Third direction S: Junction

Figure 1 is a perspective view of a display device according to an embodiment. Figure 2 is a cross-sectional view of a first embodiment of a pixel element. Figure 3A is a light output intensity-angle distribution diagram of a display device according to an embodiment. Figure 3B is a light output intensity mapping diagram of a display device according to an embodiment. Figure 4 is a cross-sectional view of a second embodiment of a pixel element. Figure 5 is a cross-sectional view of a third embodiment of a pixel element. Figure 6 is a cross-sectional view of a fourth embodiment of a pixel element. Figure 7 is a cross-sectional view of a fifth embodiment of a pixel element. Figure 8 is a cross-sectional view of a sixth embodiment of a pixel element.

11:Substrate

15: Conductive materials

20: Transparent cover

30: Pixel component

31: Micro LEDs

33: Reflective Materials

331: Groove

35: First Refractive Material

37: Second refractive material

38: Third refraction zone

C: Center axis

S: Junction

Claims (15)

A display device comprises: A display substrate comprising a plurality of pixel elements arranged in an array, wherein each pixel element comprises a micro-LED, a reflective material, a first refractive material, and a second refractive material. The reflective material is disposed on the display substrate and defines a recess, wherein an upper surface of the micro-LED is exposed in the recess. The first refractive material is disposed in the recess and covers the upper surface of the micro-LED. The second refractive material is disposed in the recess and covers the first refractive material. The boundary between the first and second refractive materials is a curved surface. The recess has a central axis, and the depth of the recess decreases with distance from the central axis. The central axis is parallel to a first direction. A transparent cover plate covers the display substrate, with a third refractive region formed between the transparent cover plate and the second refractive material. The second refractive material has a greater refractive index than the first refractive material, and the difference between the first and second refractive materials is 0.3 to 0.6. The display device has asymmetric light output in the first direction and in a second direction perpendicular to the first direction. The display device of claim 1, wherein the width of the groove decreases from a first surface of the reflective material toward the micro-luminescent diode. The display device as described in claim 2, wherein the groove is a parabola from the first surface of the reflective material toward the edge of the micro-light-emitting diode. The display device of claim 1, wherein the boundary between the first refractive material and the second refractive material is a hyperbolic surface, a parabola, an elliptical surface, or a spherical surface. The display device of claim 1, wherein the refractive index of the first refractive material is 1.4 to 1.7. The display device of claim 5, wherein the refractive index of the second refractive material is 1.4 to 2.0. The display device of claim 6, wherein the refractive index of the second refractive material is 1.8 to 1.95. The display device as described in claim 1, wherein the third refractive area is a cavity. The display device as described in claim 1, wherein the third refractive area is filled with a third refractive material, and the refractive index of the third refractive material is smaller than that of the second refractive material. A display device as described in claim 9, wherein the refractive index of the third refractive material is 1.2 to 1.6. A display device as described in claim 9, wherein a top surface of the third refractive material is coplanar with a first surface of the reflective material. The display device as described in claim 1, wherein the maximum half-height angle of the light intensity distribution in the second direction is less than or equal to +/- 20 degrees. A display device as described in claim 12, wherein the half-width angle of the light intensity distribution in the first direction is greater than or equal to +/- 40 degrees. The display device as described in claim 1, wherein each pixel element has a first side and a second side, and the length of the first side is greater than that of the second side, the first side is parallel to the first direction, and the second side is parallel to the second direction. A display device as described in claim 1, wherein the length of the vertical projection of the groove on the transparent cover in the first direction is greater than the length in the second direction.