US-12625400-B2 - Display panel

US12625400B2US 12625400 B2US12625400 B2US 12625400B2US-12625400-B2

Abstract

A display panel including a substrate, a light emitting structure layer, a C-plate, and a first bandpass polarizing reflective layer is provided. The light emitting structure layer is disposed on the substrate and includes first light emitting structures. The first light emitting structures are configured to emit excitation light of a first peak emission wavelength. The C-plate is disposed on a side of the light emitting structure layer away from the substrate. The first bandpass polarizing reflective layer is disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer. A reflectance of the first bandpass polarizing reflective layer for light with a wavelength in a first wavelength range is greater than 20%. The first wavelength range is the first peak emission wavelength±20 nm.

Inventors

Jing-Yu Wu
Chung-Yang Fang
Ping-Yen Chen
Chia-Hua Chen

Assignees

CORETRONIC CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240509
Priority Date: 20230522

Claims (13)

1 . A display panel, comprising: a substrate; a light emitting structure layer, disposed on the substrate and comprising a plurality of first light emitting structures, wherein the first light emitting structures are configured to emit excitation light of a first peak emission wavelength; a C-plate, disposed on a side of the light emitting structure layer away from the substrate; a first bandpass polarizing reflective layer, disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer, wherein a reflectance of the first bandpass polarizing reflective layer for light with a wavelength in a first wavelength range is greater than 20%, and the first wavelength range is the first peak emission wavelength±20 nm; a quarter-wave plate, disposed on a side of the C-plate away from the light emitting structure layer; and a bandpass polarizing layer, disposed on a side of the quarter-wave plate away from the light emitting structure layer and having an absorption axis, wherein the light emitting structure layer further comprises a plurality of second light emitting structures, the second light emitting structures are configured to emit excitation light of a second peak emission wavelength, the second peak emission wavelength is different from the first peak emission wavelength, the bandpass polarizing layer is overlapped with the first light emitting structures and the second light emitting structures, a transmittance of the bandpass polarizing layer for light with a wavelength in a second wavelength range is greater than 45%, the second wavelength range is the second peak emission wavelength±20 nm, and an average transmittance of the bandpass polarizing layer for light having a wavelength outside the second wavelength range and a polarizing direction parallel to the absorption axis is less than 20%.
2 . The display panel according to claim 1 , wherein a sum of phase retardation values in a thickness direction of the first bandpass polarizing reflective layer and the C-plate is less than 100 nm.
3 . The display panel according to claim 1 , wherein the second peak emission wavelength is greater than 600 nm or less than 500 nm.
4 . The display panel according to claim 1 , wherein an included angle between the absorption axis of the bandpass polarizing layer and an optical axis of the quarter-wave plate is 45 degrees.
5 . The display panel according to claim 1 , wherein the first bandpass polarizing reflective layer comprises: a base material; a plurality of cholesteric liquid crystal molecules, arranged in a twisted manner on a surface of the base material according to a helical pitch; and a plasma-treated polymer material layer, disposed between the base material and the cholesteric liquid crystal molecules, wherein inclination angles of molecular long axes of parts of the plurality of cholesteric liquid crystal molecules in contact with the plasma-treated polymer material layer relative to the surface of the base material are different from each other.
6 . The display panel according to claim 1 , wherein the first bandpass polarizing reflective layer comprises: a base material; a plurality of cholesteric liquid crystal molecules, arranged in a twisted manner on a surface of the base material according to a helical pitch; and a plurality of surface microstructures, disposed between the base material and the cholesteric liquid crystal molecules, wherein inclination angles of molecular long axes of parts of the plurality of cholesteric liquid crystal molecules in contact with the surface microstructures relative to the surface of the base material are different from each other.
7 . The display panel according to claim 1 , wherein the first bandpass polarizing reflective layer comprises: a matrix layer; and a plurality of cholesteric liquid crystal molecules, arranged in a twisted manner in the matrix layer according to a helical pitch, wherein a plurality of surface microstructures are disposed on at least one side surface of the matrix layer.
8 . A display panel, comprising: a substrate; a light emitting structure layer, disposed on the substrate and comprising a plurality of first light emitting structures, wherein the first light emitting structures are configured to emit excitation light of a first peak emission wavelength; a C-plate, disposed on a side of the light emitting structure layer away from the substrate; a first bandpass polarizing reflective layer, disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer, wherein a reflectance of the first bandpass polarizing reflective layer for light with a wavelength in a first wavelength range is greater than 20%, and the first wavelength range is the first peak emission wavelength±20 nm; and a second bandpass polarizing reflective layer, disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer, wherein the light emitting structure layer further comprises a plurality of second light emitting structures, the second light emitting structures are configured to emit excitation light of a second peak emission wavelength, the second peak emission wavelength is different from the first peak emission wavelength, a reflectance of the second bandpass polarizing reflective layer for light with a wavelength in a second wavelength range is greater than 20%, and the second wavelength range is the second peak emission wavelength±20 nm.
9 . The display panel according to claim 8 , wherein each of the first bandpass polarizing reflective layer and the second bandpass polarizing reflective layer is overlapped with the first light emitting structures and the second light emitting structures.
10 . The display panel according to claim 8 , wherein a sum of phase retardation values in a thickness direction of the first bandpass polarizing reflective layer, the second bandpass polarizing reflective layer, and the C-plate is less than 100 nm.
11 . The display panel according to claim 8 , further comprising: a third bandpass polarizing reflective layer, disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer, wherein the light emitting structure layer further comprises a plurality of third light emitting structures, the third light emitting structures are configured to emit excitation light of a third peak emission wavelength, the third peak emission wavelength is different from the first peak emission wavelength and the second peak emission wavelength, a reflectance of the third bandpass polarizing reflective layer for light with a wavelength in a third wavelength range is greater than 20%, and the third wavelength range is the third peak emission wavelength±20 nm.
12 . The display panel according to claim 11 , wherein each of the first bandpass polarizing reflective layer, the second bandpass polarizing reflective layer and the third bandpass polarizing reflective layer is overlapped with the first light emitting structures, the second light emitting structures and the third light emitting structures.
13 . The display panel according to claim 8 , further comprising: a quarter-wave plate, disposed on a side of the C-plate away from the light emitting structure layer; and a bandpass polarizing layer, disposed on a side of the quarter-wave plate away from the light emitting structure layer and having an absorption axis, wherein the light emitting structure layer further comprises a plurality of third light emitting structures, the third light emitting structures have a third peak emission wavelength, the third peak emission wavelength is different from the first peak emission wavelength and the second peak emission wavelength, the bandpass polarizing layer is overlapped with the first light emitting structures, the second light emitting structures, and the third light emitting structures, a transmittance of the bandpass polarizing layer for light with a wavelength in a third wavelength range is greater than 45%, the third wavelength range is the third peak emission wavelength±20 nm, and an average transmittance of the bandpass polarizing layer for light having a wavelength outside the third wavelength range and a polarizing direction parallel to the absorption axis is less than 20%.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the priority benefit of China application serial no. 202310573766.8, filed on May 22, 2023. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. BACKGROUND Technical Field The invention relates to a display technology and particularly relates to a display panel. Description of Related Art In recent years, there has been a growing trend favoring organic light emitting diode (OLED) display panels and micro light emitting diode (micro-LED) display panels. This is primarily attributed to their high color saturation, fast response, and good display quality with high contrast. In order to enhance a light output efficiency of these self-luminous display panels, most of the electrode located on a side of the LED away from a light exit surface are reflective electrodes. Since these reflective electrodes reflect external ambient light, when the display panel exhibits a full-screen black screen or a local dark state, human eyes may easily detect the reflection of the external ambient light caused by the reflective electrodes, thus resulting in a decrease in display quality or appearance taste. To address the above-mentioned issue, a technical solution to place a circular polarizer on one side of the light exit surface of the self-luminous display panel has been proposed. The placement of the circular polarizer serves to transform the incoming external ambient light into circularly-polarized light with specific handedness, and the circularly-polarized light forms circularly-polarized light with reverse handedness after being reflected by the reflective electrodes. The circularly-polarized light with the reverse handedness cannot pass through the circular polarizer. Accordingly, a reflectance of the self-luminous display panel for the external ambient light is reduced. However, the implementation of such a circular polarizer leads to a decrease in an overall light output of the self-luminous display panel; for instance, the brightness may decrease by at least 55%. The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art. SUMMARY In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a display panel that includes a substrate, a light emitting structure layer, a C-plate, and a first bandpass polarizing reflective layer. The light emitting structure layer is disposed on the substrate and includes a plurality of first light emitting structures, where the first light emitting structures are configured to emit excitation light of a first peak emission wavelength. The C-plate is disposed on a side of the light emitting structure layer away from the substrate. The first bandpass polarizing reflective layer is disposed between the light emitting structure layer and the C-plate and overlapped with the light emitting structure layer, where a reflectance of the first bandpass polarizing reflective layer for light with a wavelength in a first wavelength range is greater than 20%, and the first wavelength range is the first peak emission wavelength±20 nm. Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. FIG. 1A and FIG. 1B are schematic cross-sectional diagrams of a display panel according to a first embodiment of the invention. FIG. 2 is a schematic diagram of an axial direction of the absorption axis of the bandpass polarizing layer and an axial direction of the optical axis of the quarter-wave plate (QWP) in FIG. 1A. FIG. 3 is a schematic cross-sectional diagram of the first bandpass polarizing reflective layer or the second bandpass polarizing reflective layer in FIG. 1A. FIG. 4 is a distribution curve diagram of brightness of the display panel in FIG. 1A and a display panel in a comparative example at different wavelengths. FIG. 5 is a distribution curve diagram of a refl