Off-axis visual angle enhanced display based on quantum dot technology and light path regulation and control method

Abstract

The invention discloses an off-axis visual angle enhanced display based on a quantum dot technology, and belongs to the technical field of display. The display sequentially comprises a polaroid, a color filter film, a liquid crystal layer, a TFT driving substrate, a 1 / 4 wave plate, a Bragg reflection layer, a microprism structure layer, a chiral liquid crystal layer and a quantum dot backlight layer from top to bottom. According to the invention, a polarization screening and light path circulation system is constructed by matching the backlight narrow-band light-emitting characteristic of quantum dots with the narrow-band reflection characteristic of the Bragg reflection layer and combining the synergistic effect of the chiral liquid crystal layer, the microprism structure layer and the polarization optical element; according to the technical scheme, light which is originally ineffective at a positive view angle and a small off-axis view angle is reflected and scattered and converted into effective emergent light at a large off-axis view angle, so that the brightness uniformity and the light utilization efficiency of the off-axis view angle of the display are remarkably improved, the color cast is reduced, and the problems of brightness attenuation and color cast during off-axis view in a traditional display technology are solved. The scheme has technical universality and can be adapted to various display technologies.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to off-axis viewing angle enhanced displays based on quantum dot technology and optical path control methods. Background Technology

[0002] In the display field, liquid crystal displays (LCDs) generally suffer from viewing angle dependence due to the inherent optical anisotropy of their liquid crystal molecules. When the observer's line of sight deviates from the screen's normal, phenomena such as brightness attenuation, contrast reduction, and color distortion easily occur. This technical bottleneck is particularly pronounced in certain application scenarios, such as automotive displays, medical displays, industrial control displays, and commercial advertising displays, where off-axis viewing angles are frequently used. In these cases, the display quality of traditional LCDs deteriorates rapidly, severely impacting the user experience. Compared to LCDs, newer self-emissive display technologies such as organic light-emitting diodes (OLEDs), Mini LEDs, and Micro LEDs have indeed shown significant improvements in viewing angle contrast. However, these technologies do not fundamentally solve the problem of optical performance degradation at off-axis viewing angles. The propagation of light within the display medium and at interfaces is still affected by the viewing angle, resulting in brightness loss and color shift even when viewed off-axis. Therefore, developing a core optical solution that can universally improve the off-axis viewing angle performance of multiple display technologies, rather than only optimizing a single display technology locally, has become a key technical challenge that urgently needs to be overcome in this field.

[0003] In the field of optical control, structures based on the Bragg reflection principle (such as Bragg liquid crystal layers) provide an effective way to achieve precise light manipulation. However, Bragg reflection is essentially a wavelength-selective reflection, and its efficient operation usually depends on a relatively narrow wavelength band. Traditional white backlights or ordinary LED light sources have broad spectra, making it difficult for Bragg reflection structures to achieve uniform and efficient angle control of all wavelength components. This limits their effectiveness in improving overall viewing angle performance in full-color displays.

[0004] Meanwhile, quantum dot display technology has attracted much attention due to its unique optical properties. Quantum dot materials can emit light with extremely narrow half-width at half-maximum and extremely high color purity, and its emission wavelength can be precisely controlled. This "narrow-band" emission characteristic is an ideal match for the high-efficiency operating wavelength requirements of Bragg reflector structures. This provides a prerequisite for building an efficient viewing angle enhancement system based on wavelength selective reflection. However, in existing technologies, how to innovatively integrate the narrow-band emission advantages of quantum dots with Bragg reflector structures to develop an effective off-axis viewing angle enhancement solution specifically for high color gamut displays remains an area of ​​insufficient exploration.

[0005] Therefore, developing a core optical solution that can fully utilize the narrow-band light-emitting characteristics of quantum dots and work in conjunction with narrow-band optical elements such as Bragg reflection to universally improve the off-axis viewing angle performance of display devices has become a key technical challenge that urgently needs to be overcome in this field. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems by providing an off-axis viewing angle enhanced display and an optical path control method based on quantum dot technology.

[0007] The technical solution of this application is implemented as follows: In a first aspect, this application provides an off-axis viewing angle enhancement display based on quantum dot technology. The display, from the light emission direction, comprises: a polarizer; a color filter; a liquid crystal layer; a TFT driving substrate; a quarter-wave plate; a Bragg reflector layer composed of cholesteric liquid crystal for angle-selective reflection of circularly polarized light with a specific rotation direction; a microprism structure layer; a chiral liquid crystal layer (8, composed of cholesteric liquid crystal for selective transmission of circularly polarized light with a specific rotation direction); and a quantum dot backlight layer; wherein the chiral liquid crystal layer and the Bragg reflector layer have opposite molecular helical directions, and the narrow-band emission of the quantum dot backlight layer matches the reflection center wavelength of the Bragg reflector layer. Secondly, this application also provides an optical path control method for transmitting circularly polarized light, predominantly at large angles, transmitted from the Bragg reflector layer, which is configured to pass sequentially through the quarter-wave plate and the polarizer; wherein the quarter-wave plate is configured to convert the circularly polarized light into linearly polarized light, and the polarization direction of the linearly polarized light is perpendicular to the transmission axis of the polarizer; the polarizer is configured to allow the linearly polarized light to pass through to form a final display image.

[0008] The advantages or beneficial effects of the above technical solutions include at least the following: Compared with traditional technologies, the gains of this invention mainly include two aspects. First, it significantly improves light utilization efficiency and reduces system power consumption. Traditional wide-viewing-angle technologies (such as adding diffusers or multi-domain designs) often sacrifice front brightness and light efficiency. This invention creatively constructs an optical path of "polarization screening-Bragg reflection-scattering recycling," meaning that the "ineffective" polarized light reflected by the chiral liquid crystal layer is not simply absorbed, but undergoes multiple reflections, scattering, and polarization conversions within the system via the Bragg reflection layer and microprism structure, ultimately transforming into "effective" light energy output. This significantly reduces the ineffective loss of light, which means that higher screen brightness can be achieved with the same power consumption, or lower power consumption can be achieved with the same brightness requirements. Second, the solution of this invention has technical universality. The multi-layer optical architecture proposed in this invention is a relatively independent enhancement module that can be adapted to various display technologies based on liquid crystal modulation (such as LCD, Mini-LED backlight, etc.). This solution innovates from the perspective of optical path principle, rather than simply relying on improvements in underlying display technology, providing a universal, efficient, and easily integrated technical path for the entire industry to upgrade the viewing angle performance of products. Attached Figure Description

[0009] The accompanying drawings illustrate exemplary embodiments of the present application and, together with the description thereof, serve to explain the principles of the present application. These drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification.

[0010] Figure 1 This is a schematic cross-sectional view of an off-axis viewing angle enhancement display based on quantum dot technology proposed in this invention.

[0011] Figure 2 This is a top view of a microprism structure layer of an off-axis viewing angle enhancement display based on quantum dot technology proposed in this invention.

[0012] Figure 3 This is a general outline of the off-axis viewing angle enhancement display based on quantum dot technology proposed in this invention.

[0013] Figure 4 This is a simulation comparison of the viewing angle brightness distribution before and after the 550nm wavelength light proposed in this invention passes through the Bragg reflector layer.

[0014] Figure 5 This is a schematic diagram of the molecular arrangement of the chiral liquid crystal layer and the Bragg liquid crystal layer proposed in this invention. Detailed Implementation

[0015] To enable those skilled in the art to further understand the present invention, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the drawings are for illustrative purposes only and are not drawn to scale.

[0016] A cross-sectional structural schematic diagram of the present invention is shown below. Figure 1 As shown, the structure of the present invention, from top to bottom, consists of: a polarizer 1, a color filter 2, a liquid crystal layer 3, a TFT driver 4, a quarter-wave plate 5, a Bragg reflector layer 6, a microprism structure layer 7, a chiral liquid crystal layer 8, and a quantum dot backlight layer 9. Detailed Implementation

[0017] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0018] It should be noted that, where there is no conflict, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be understood that the term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this application are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0020] It should be noted that the terms "one" and "more" used in this application are illustrative rather than restrictive. Those skilled in the art should understand that, unless explicitly stated in the context, they should be interpreted as "one or more". [Singular / Plural] The names of the messages or information exchanged between multiple devices in the embodiments of this application are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0021] A cross-sectional structural schematic diagram of the present invention is shown below. Figure 1As shown, the structure of the present invention, from top to bottom, consists of: a polarizer 1, a color filter 2, a liquid crystal layer 3, a TFT driver 4, a quarter-wave plate 5, a Bragg reflector layer 6, a microprism structure layer 7, a chiral liquid crystal layer 8, and a quantum dot backlight layer 9.

[0022] Figure 1 This is a cross-sectional structural diagram of an off-axis viewing angle enhancement display based on quantum dot technology proposed in this invention. By adjusting polarization and scattering, precise control of the viewing angle and brightness of the emitted light can be achieved. The upper surface of the chiral liquid crystal layer 8 is a microprism structure layer 7, which works in sequence with the optical rotation characteristics corresponding to Bragg reflection 6.

[0023] Figure 2 This is a top view of a microprism structure layer of an off-axis viewing angle enhancement display based on quantum dot technology proposed in this invention. The microgrooves are arranged vertically, causing the reflected left-handed circularly polarized light to undergo a change in the optical path mainly in the left-right direction, modulating the perpendicularly incident or small-angle incident light waves to exit at a larger off-axis angle.

[0024] Combination Figure 3 The optical modulation process of the present invention is illustrated below. The propagation and modulation process of light in the multilayer structure is described in detail below: For ease of description, a light wave with a center wavelength of 550nm is used as an example, and the parameters of each optical element are assumed to be as follows: the transmission axis of polarizer 1 is 90°; the fast axis of quarter-wave plate 5 is 45°; the Bragg reflector layer 6 is composed of a left-handed cholesteric liquid crystal with a center reflection wavelength of 550nm, which can reflect left-handed circularly polarized light; the chiral liquid crystal layer 8 is composed of a right-handed cholesteric liquid crystal, which can reflect normally incident right-handed circularly polarized light; the microprism structure layer 7 can scatter light and change its propagation angle, without substantially changing the polarization state of the light.

[0025] The optical path modulation process is mainly divided into three stages: Phase 1: Backlight Polarization and Initial Loop 550nm natural light from the quantum dot backlight layer 9 first enters the chiral liquid crystal layer 8. This layer acts as a rotation selector, transmitting left-handed circularly polarized light while reflecting right-handed circularly polarized light. The reflected right-handed light returns to the backlight layer, undergoes depolarization due to the diffuse reflection structure inside the backlight layer, and becomes natural light again, which is then re-entered into the chiral liquid crystal layer 8. This process repeats continuously until, ultimately, all the natural light emitted from the quantum dot backlight layer 9 is efficiently converted into left-handed circularly polarized light and passes through the chiral liquid crystal layer 8, completing the initial polarization of the backlight. Phase Two: Viewpoint-dependent Polarization and Spatial Sorting Left-handed light transmitted from the chiral liquid crystal layer 8 then passes through the microprism structure layer 7, which scatters the light, diversifying its propagation direction to include both small-angle (near the normal direction) and large-angle (off-axis) light. Subsequently, this left-handed light enters the Bragg reflection layer 6, which acts as an angle and polarization filter. Its characteristics are as follows: left-handed light incident perpendicularly or at small angles is reflected by this layer because it satisfies the Bragg reflection condition; left-handed light incident at large angles is directly transmitted because it does not satisfy the Bragg condition, and the transmitted large-angle left-handed light will directly enter the subsequent display module. Phase 3: Optical Path Loop and Viewpoint Optimization The small-angle left-handed light reflected back by the Bragg reflector layer 6 has its propagation direction reversed. This reverse-propagating left-handed light is scattered again by the microprism structure layer 7, and its propagation angle is further modulated before it reaches the lower surface of the chiral liquid crystal layer 8 again. The key mechanism is that the chiral liquid crystal layer 8 will also Bragg reflect this reverse-propagating left-handed light incident on the lower surface (i.e., the backlight side). This is because the selective reflection characteristics of chiral liquid crystals are closely related to the direction of light propagation. For a given helical structure (here, right-handed), it reflects light with a direction opposite to its helical direction. The circularly polarized light propagates in the opposite direction, so this reverse left-handed light is effectively reflected back to the microprism structure layer 7 by the chiral liquid crystal layer 8. Thereafter, the light passes between the Bragg reflector layer 6 (reflecting small-angle left-handed light) and the chiral liquid crystal layer 8 (reflecting the reverse-propagating left-handed light), and is continuously angularly modulated by the microprism structure layer 7 to form a closed optical path resonant circulation cavity. In this circulation process, the light is continuously scattered and its angle is changed. Once its angle is modulated to the point that it does not meet the reflection condition of the Bragg reflector layer 6 (i.e., becomes a large angle), it will be transmitted through the Bragg reflector layer 6 as useful output light.

[0026] Finally, the left-handed light, mainly at large angles, transmitted from the Bragg reflector layer 6 passes sequentially through the quarter-wave plate 5 and the polarizer 1. The quarter-wave plate 5 converts it into linearly polarized light perpendicular to the transmission axis of the polarizer 1, thus allowing it to pass through efficiently and form the final image. Through the above-mentioned precise optical path design, the present invention successfully "captures" and converts small-angle light that would otherwise be lost into effective off-axis viewing angle output light, fundamentally solving the problems of brightness attenuation and color shift in traditional displays under off-axis viewing angles.

[0027] Figure 4 This is a comparison diagram of the viewing angle brightness distribution before and after the 550nm wavelength light proposed in this invention passes through the Bragg reflector layer. It can be seen that at a wavelength of 550nm, the transmittance of the chiral liquid crystal layer to light exhibits a specific pattern with the change of viewing angle. The transmittance reaches its peak (close to 1.0) at about -40° and 40°, while the transmittance is low near 0°, showing obvious viewing angle selective transmission characteristics.

[0028] Figure 5 This is a schematic diagram of the molecular arrangement of the chiral liquid crystal layer 8 and the Bragg reflective layer 6 proposed in this invention. It clearly shows that the molecular helical orientations of the two are in opposite directions: if any one layer of molecules is arranged in a clockwise helical pattern, then the other layer of molecules must be arranged in a counterclockwise helical pattern. In addition, the pitch of the chiral liquid crystal layer is continuously distributed, while the pitch of the Bragg liquid crystal layer is a fixed value.

[0029] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] Those skilled in the art should understand that the above embodiments are merely for illustrative purposes and are not intended to limit the scope of this application. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of this application.

Claims

1. An off-axis viewing angle enhancement display based on quantum dot technology, characterized in that, The display comprises, in sequence from the light-emitting direction: a polarizer (1); a color filter (2); a liquid crystal layer (3); a TFT driving substrate (4); a quarter-wave plate (5); a Bragg reflector layer (6) composed of cholesteric liquid crystal, used for angle-selective reflection of circularly polarized light with a specific rotation direction; a microprism structure layer (7); a chiral liquid crystal layer (8) composed of cholesteric liquid crystal, used for selective transmission of circularly polarized light with a specific rotation direction; and a quantum dot backlight layer (9); wherein the chiral liquid crystal layer (8) has the opposite molecular helical rotation direction to the Bragg reflector layer (6), and the narrow-band emission of the quantum dot backlight layer (9) matches the reflection center wavelength of the Bragg reflector layer (6).

2. The off-axis viewing angle enhancement display based on quantum dot technology according to claim 1, characterized in that: The Bragg reflector layer (6) is configured to reflect circularly polarized light of a specific direction that is incident vertically and at a small angle, and to transmit circularly polarized light of the same direction that is incident at a large angle.

3. The off-axis viewing angle enhancement display based on quantum dot technology according to claim 1, characterized in that: The microprism structure layer (7) is disposed between the Bragg reflection layer (6) and the chiral liquid crystal layer (8) to scatter light to change its propagation direction, while basically not changing the polarization state of the light.

4. The off-axis viewing angle enhancement display based on quantum dot technology according to claim 1, characterized in that: The chiral liquid crystal layer (8) is configured to allow circularly polarized light of a specific direction to pass through when incident from the backlight side in the forward direction, and to reflect circularly polarized light of the opposite direction when incident from the backlight side in the reverse direction.

5. The off-axis viewing angle enhancement display based on quantum dot technology according to claim 1, characterized in that: The Bragg reflection wavelength of the Bragg reflector layer (6) matches the center wavelength of the light source of the quantum dot backlight layer (9).

6. The off-axis viewing angle enhancement display based on quantum dot technology according to claim 1, characterized in that: The pitch of the chiral liquid crystal layer (8) is continuously variable, while the pitch of the Bragg reflective layer (6) is a fixed value.

7. The off-axis viewing angle enhancement display based on quantum dot technology according to any one of claims 1-4, characterized in that: The quantum dot backlight layer (9) emits red and green light when excited by blue light, and mixes with some blue light to form narrow-band white light.

8. A method for optical path control of an off-axis viewing angle enhancement display as described in any one of claims 1-7, characterized in that, Includes the following steps: The natural light emitted by the quantum dot backlight layer (9) is filtered by the chiral liquid crystal layer (8) and converted into first circularly polarized light. The first circularly polarized light is scattered by the microprism structure layer (7) and then incident on the Bragg reflection layer (6). The Bragg reflection layer (6) reflects the small-angle first circularly polarized light in the incident light that meets the Bragg reflection condition and transmits the large-angle first circularly polarized light that does not meet the condition. The reflected small-angle first circularly polarized light propagates in the opposite direction, is scattered again by the microprism structure layer (7) and its angle is changed, and then it is reflected by the chiral liquid crystal layer (8). Thus, it circulates in the optical path circulation cavity composed of the Bragg reflection layer (6), the microprism structure layer (7) and the chiral liquid crystal layer (8) until its angle is modulated to a large angle and transmitted by the Bragg reflection layer (6).

9. The optical path control method according to claim 8, characterized in that: Circularly polarized light, predominantly at large angles, transmitted from the Bragg reflector layer (6) is configured to pass sequentially through the quarter-wave plate (5) and the polarizer (1); wherein the quarter-wave plate (5) is configured to convert the circularly polarized light into linearly polarized light, and the polarization direction of the linearly polarized light is perpendicular to the transmission axis of the polarizer (1); the polarizer (1) is configured to allow the linearly polarized light to pass through in order to form the final display image.

10. The optical path control method according to claim 9, characterized in that: In the initial screening of the chiral liquid crystal layer (8), the reflected circularly polarized light with opposite rotation returns to the quantum dot backlight layer (9) and undergoes depolarization, participating in the cycle again as natural light.

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