A view angle controller for automobile center display screen and co-pilot display screen

Abstract

A kind of view angle controller for car central display screen and co-pilot display screen, it is composed of twisted nematic liquid crystal layer, +C compensation film and polarizer arranged in sequence;The inside of twisted nematic liquid crystal layer includes upper substrate and lower substrate, the liquid crystal orientation direction of lower substrate is A, the liquid crystal orientation direction of upper substrate is B, A=B-90°, liquid crystal is twisted in A to B in layer;The driving voltage V1 of twisted nematic liquid crystal layer satisfies: 1.2V≤V<1.8V;The retardation value of twisted nematic liquid crystal layer is in the range of 900nm-1100nm;The absorption axis angle of polarizer is set as B, B is 125°, 130°, 135°, 140° or 145°, so A=35°, B=125° or A=40°, B=130° or A=45°, B=135° or A=50°, B=140° or A=55°, B=145°.The transmittance T1 of view angle controller satisfies 0.2<T<0.76.The present application achieves the effect of upper view angle anti-peeping, solves the problem of light leakage, ensures that the line of sight of driver is clear, and gives consideration to the viewing experience of co-pilot.

Description

Technical Field

[0001] This invention relates to the field of vehicle displays, and more specifically to a viewing angle controller for a central display screen and a passenger-side display screen in a car. Background Technology

[0002] With the rapid development of intelligent vehicles, in-vehicle displays have become one of the core components of automotive infotainment systems. From the initial simple panels to today's large-size, high-resolution touchscreens, the display quality, interactive experience, and integration of in-vehicle displays have significantly improved.

[0003] Viewing angle control technology is a key technology in in-vehicle displays, especially when display sharing is achieved between the driver and passengers. This technology adjusts the direction of light propagation from the display to ensure that content is visible only to specific passengers at certain angles, while maintaining privacy for others. This technology plays a crucial role in improving driving safety, reducing driver distraction from entertainment screens, and providing a personalized display experience.

[0004] Currently, there is no suitable technology to block light from being emitted into the windshield, resulting in low transmittance for the driver and front passenger, and it is also impossible to achieve an upward-view privacy protection effect. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the defects in the existing technology and propose a viewing angle controller for the central display screen and the passenger-side display screen of a car. It can block light from being emitted into the windshield, eliminate virtual images, and at the same time maintain high transmittance for the driver and the passenger, so as to achieve the effect of anti-peeping from the upper viewing angle, solve the problem of light leakage, ensure clear vision for the driver, and take into account the viewing experience of the passenger.

[0006] To solve the above-mentioned technical problems, the present invention proposes the following technical solution: a viewing angle controller for a car central display screen and a passenger-side display screen, which consists of a twisted nematic liquid crystal layer, a +C compensation film and a polarizer arranged in sequence; The interior of the twisted nematic liquid crystal layer includes an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B, where A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V1 of the twisted nematic liquid crystal layer satisfies: 1.2V ≤ V < 1.8V; The retardation value of the twisted nematic liquid crystal layer is defined in the range of 900nm-1100nm; The angle of the analyzer's absorption axis is set to B, which can be 125°, 130°, 135°, 140°, or 145°. Therefore, A=35°, B=125°, or A=40°, B=130°, or A=45°, B=135°, or A=50°, B=140°, or A=55°, B=145°. The transmittance T1 of the viewing angle controller satisfies 0.2 < T < 0.76.

[0007] A further limitation of the above technical solution is that the viewing angle controller for the central display screen and the passenger-side display screen of the car also includes a polarizer, which is located on the outside of the twisted nematic liquid crystal layer, and the absorption axis angle of the polarizer is set to A, and the delay value of the +C compensation film is 100nm.

[0008] To solve the above-mentioned technical problems, the present invention proposes the following technical solution: a viewing angle controller for a central display screen and a passenger-side display screen in an automobile, which consists of a first layer of twisted nematic liquid crystal layer, a modulation polarizer, a second layer of twisted nematic liquid crystal layer, a second layer of +C compensation film and a polarizer arranged in sequence. The first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer both include an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B, where A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V2 of the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer satisfies: 1.2V≤V2<1.8V; The range of retardation values ​​for the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer is set to 900nm-1100nm; The absorption axis angle of the modulation polarizer is set to B; The angle of the analyzer's absorption axis is set to A, which can be 35°, 40°, 45°, 50°, or 55°. Therefore, A=35°, B=125°, or A=40°, B=130°, or A=45°, B=135°, or A=50°, B=140°, or A=55°, B=145°. The transmittance T2 of the viewing angle controller satisfies 0.2 < T2 < 0.76.

[0009] A further limitation of the above technical solution is that the viewing angle controller for the central display screen and the passenger-side display screen of the car also includes a polarizer, which is located outside the first layer of twisted nematic liquid crystal layer, and the absorption axis angle of the polarizer is set to A.

[0010] A further limitation of the above technical solution is that the viewing angle controller for the central display screen and the passenger-side display screen of the car also includes a first +C compensation film, which is disposed between the first twisted nematic liquid crystal layer and the modulation polarizer.

[0011] A further limitation of the above technical solution is that the delay values ​​of the first +C compensation film and the second +C compensation film are both 100nm.

[0012] To solve the above-mentioned technical problems, the present invention proposes the following technical solution: a viewing angle controller for a central display screen and a passenger-side display screen in an automobile, which consists of a first layer of twisted nematic liquid crystal layer, a first layer of +C compensation film, a modulation polarizer, a second layer of twisted nematic liquid crystal layer and an analyzer arranged in sequence. The first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer both include an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B, where A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V3 for the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer satisfies: 1.2V ≤ V3 < 1.8V; The range of retardation values ​​for the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer is set to 900nm-1100nm; The absorption axis angle of the modulation polarizer is set to B; The angle of the analyzer's absorption axis is set to A, which can be 35°, 40°, 45°, 50°, or 55°. Therefore, A=35°, B=125°, or A=40°, B=130°, or A=45°, B=135°, or A=50°, B=140°, or A=55°, B=145°. The transmittance T3 of the viewing angle controller satisfies 0.2 < T3 < 0.76.

[0013] A further limitation of the above technical solution is that the viewing angle controller for the central display screen and the passenger-side display screen of the car also includes a polarizer, which is located outside the first layer of twisted nematic liquid crystal layer, and the absorption axis angle of the polarizer is set to A.

[0014] A further limitation of the above technical solution is that the viewing angle controller for the central display screen and the passenger-side display screen of the car also includes a second +C compensation film, which is disposed between the second twisted nematic liquid crystal layer and the analyzer.

[0015] A further limitation of the above technical solution is that the delay values ​​of the first +C compensation film and the second +C compensation film are both 100nm.

[0016] This invention offers the following advantages: It is used as a viewing angle controller for the central display screen and passenger-side display screen in automobiles, enabling dynamic switching between normal and safe modes to achieve an anti-peeping effect from the upper viewing angle. This invention also solves the problem of light leakage. The core advantage of this invention lies in its ability to intelligently adjust light transmittance and viewing angle characteristics based on the relative position of the driver and the display screen, ensuring clear vision for the driver while also considering the passenger's viewing experience. Compared to other viewing angle control methods, this invention is more energy-efficient and reduces costs. This invention can block light from being emitted into the windshield, eliminating virtual images while maintaining high transmittance for both the driver and passenger. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a single-layer view controller according to Embodiment 1 of the present invention.

[0018] Figure 2 This is a diagram showing the changes in polarization state of light at wavelengths of 450 nm, 550 nm, and 650 nm (at 90° azimuth and 70° polar angles) after passing through a twisted nematic liquid crystal layer and a +C compensation film.

[0019] Figure 3 This is a schematic diagram of the assembly of a single-layer viewing angle controller and a display panel according to Embodiment 1 of the present invention.

[0020] Figure 4 This is a diagram showing the changes in tilt angle and azimuth angle of the twisted nematic liquid crystal layer in Example 1 under a driving voltage of less than 1.8V.

[0021] Figure 5 This is the isotransmittance diagram of the single-layer viewing angle controller in Embodiment 1.

[0022] Figure 6 A schematic diagram of the structure of a single-layer view controller according to Embodiment 2 of the present invention.

[0023] Figure 7 A schematic diagram of the structure of the dual-viewpoint controller in Embodiment 3 of the present invention.

[0024] Figure 8 This is a schematic diagram of the assembly of the dual-viewpoint controller and display panel in Embodiment 3.

[0025] Figure 9 This is a performance simulation analysis diagram of Example 3 when the dual-view controller integrates both OLED (Huawei P30) and LCD (iPhone SE2) displays.

[0026] Figure 10 This is the transmittance-wavelength curve of the dual-viewpoint controller in Example 3 at azimuth angles of 270° and 90°.

[0027] Figure 11These are images taken from different angles, illustrating the integration of the dual-view controller with an OLED display (Apple Watch SE) in Embodiment 3.

[0028] Figure 12 This is a schematic diagram of the assembly of the dual-view controller and display panel in Embodiment 4.

[0029] Figure 13 This is a schematic diagram of the assembly of the dual-view controller and display panel in Embodiment 5.

[0030] Figure 14 This is a schematic diagram of the assembly of the dual-viewpoint controller and display panel in Embodiment Six.

[0031] Figure 15 This is a schematic diagram of the assembly of the dual-viewpoint controller and display panel in Embodiment 7.

[0032] Figure 16 This is a schematic diagram of the assembly of the dual-viewpoint controller and display panel in Embodiment 8. Detailed Implementation

[0033] To make the technical means, creative features, achieved objectives, and effects of this invention easier to understand, the invention is further described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are merely preferred embodiments of this invention and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention.

[0034] This invention proposes a viewing angle controller for a car's central display screen and passenger-side display screen. The following embodiments one to eight are studies on the case where the polarizer absorption axis is 45° and the analyzer absorption axis is 135°. The case where the polarizer absorption axis is not 45° and the analyzer absorption axis is not 135° is further studied. Example

[0035] like Figure 1 As shown, this is an embodiment of the viewing angle controller for a central display screen and a passenger-side display screen of an automobile according to the present invention. The first embodiment is a single-layer viewing angle controller 100, which consists of a polarizer 11, a twisted nematic liquid crystal layer 12, a +C compensation film 13 and an analyzer arranged in sequence.

[0036] The polarizer 11 is located on the outside of the twisted nematic liquid crystal layer 12.

[0037] The absorption axis of the polarizer 11 is set to 45°.

[0038] The retardation value of the twisted nematic liquid crystal layer 12 is 1000 nm.

[0039] The retardation value of the +C compensation film 13 is 100 nm.

[0040] The absorption axis of the analyzer 14 is set to 135°.

[0041] The twisted nematic liquid crystal layer 12 includes an upper substrate (not shown) and a lower substrate (not shown) uniformly coated with a polyimide layer to achieve the twisting of liquid crystal molecules. The liquid crystal alignment direction of the lower substrate is 45°, the liquid crystal alignment direction of the upper substrate is 135°, and the pretilt angle of both is 2°. The liquid crystal is twisted from 45° to 135° in the layer.

[0042] +C compensation film 13 is located between the twisted nematic liquid crystal layer 12 and the analyzer 14 to enhance viewing angle characteristics.

[0043] The twisted nematic liquid crystal layer 12 can achieve electro-optical switching between the normal mode and the safe mode of the display. It should be noted that the normal mode and the safe mode mentioned in this article refer to the following: the normal mode is characterized by a wide viewing angle, and the safe mode is characterized by a narrow viewing angle.

[0044] However, in safe mode, significant light leakage occurs within a polar angle range exceeding 40°. To address this issue, a +C compensation film 13 is introduced to reduce light leakage at large polar angles. The +C compensation film 13 is added between the twisted nematic liquid crystal layer 12 and the analyzer 14, and its optical compensation mechanism is explained using a Poincaré sphere. Figure 2 The changes in polarization state of light at wavelengths of 450 nm, 550 nm, and 650 nm (at 90° azimuth and 70° polar angles) after passing through the twisted nematic liquid crystal layer 12 and the +C compensation film 13 are shown. Compared to the case using only the twisted nematic liquid crystal layer 12, the polarization state of light after passing through the +C compensation film 13 is closer to the equator of the Poincaré sphere. This indicates that the polarization of light is more linear and more aligned with the absorption axis (point A2) of the analyzer 14, thereby reducing transmittance in that direction.

[0045] Figure 2 In the diagram, A1 is the absorption axis of polarizer 11, A2 is the absorption axis of analyzer 14, T1 is the transmission axis of polarizer 11, and T2 is the transmission axis of analyzer 14.

[0046] like Figure 3 The diagram shown is a schematic of the assembly of the single-layer viewing angle controller 100 and the display panel 10000 in Embodiment 1. The display panel 10000 is located on the outside of the polarizer 11.

[0047] Due to the anchoring effect, the liquid crystal molecules in the twisted nematic liquid crystal layer 12 do not tilt on the substrate surface. When no driving voltage is applied, the liquid crystal orientation remains approximately parallel to the substrate surface. Therefore, the viewing effect of the liquid crystal changes very little in different viewing directions, maintaining stable and high light transmittance in both frontal and oblique viewing directions. After applying a vertical electric field, the liquid crystal molecules in the twisted nematic liquid crystal layer 12 undergo changes in tilt and twist angles, resulting in different performance changes in the liquid crystal in different viewing directions. Consequently, the transmittance varies greatly at the upper viewing angle, while the variations at the left, right, and lower viewing angles are smaller.

[0048] Unlike regular displays, many in-vehicle center display (CID) and passenger display (CDD) are tilted to allow users to view the vehicle from an angle. However, this design presents a challenge: in safety mode, the viewing angle controller blocks light emitted towards the windshield, resulting in a narrow viewing angle for the display panel, while in normal mode, it regains its wide viewing angle.

[0049] The transmittance of the twisted nematic liquid crystal layer 12 is determined by its optical axis direction and phase retardation, which are related to the optical anisotropy of the liquid crystal and its tilt angle. Simulation calculations were performed on the twisted nematic liquid crystal layer 12 to obtain the tilt angle and azimuth angle changes with a driving voltage less than 1.8V, such as... Figure 4 As shown, (a) is viewed from a normal viewing angle, and (b) is viewed from a tilted 40° polar angle (90° azimuth angle). At a normal viewing angle, the azimuth angle of the liquid crystal in the liquid crystal layer changes almost linearly with increasing voltage, with a small change. Furthermore, the tilt angle of the liquid crystal is not large, and the phase retardation of the liquid crystal layer at 1.8V is still sufficiently large under normal viewing conditions, thus maintaining a high transmittance. At a tilted viewing angle of 40°, as the voltage exceeds 1.6V, the equivalent tilt angle of the liquid crystal increases, leading to a significant change in the equivalent azimuth angle. This results in almost no rotation of the liquid crystal near the substrate, while the tilt angle of the intermediate liquid crystal is larger. Even with azimuth angle changes, it cannot exhibit significant polarization rotation and birefringence effects, thus significantly reducing transmittance. This effect makes the twisted nematic liquid crystal layer 12 suitable for high-viewing-angle privacy protection applications.

[0050] Table 1: Transmittance at different polar angles under different driving voltages at azimuth angles of 0°, 45°, and 90°

[0051]

[0052] Please refer to Table 1 for the selection of the optimal driving voltage: The transmittance at different polar angles under different driving voltages was selected at azimuth angles of 0°, 45°, and 90°. At 0° azimuth angle, 1.2-1.6V maintains high transmittance at all polar angles, while 1.8V-2V results in a significant drop in transmittance at all polar angles, failing to achieve the desired effect. At 90° azimuth angle, 1.4V and 1.2V still maintain high transmittance at 20-30° polar angles, while at 1.8V and 2V, the transmittance loss at the center (0° polar angle) is too large. At 45° azimuth angle, only 1.6V minimizes light leakage at large polar angles without loss of center transmittance. Therefore, the optimal driving voltage V1 is 1.6V (and V1 ranges from 1.2V to V1 < 1.8V). It should be noted that this application uses the Gray second extreme value method to calculate and select the TN liquid crystal cell and calculates the compensation value of the TN liquid crystal cell to reduce the loss of center transmittance by changing the voltage.

[0053] The beneficial effects of the single-layer viewing angle controller 100 in Example 1: The performance of the above-mentioned single-layer viewing angle controller 100 integrated into both OLED (Huawei P30) and LCD (iPhone SE2) displays was simulated and analyzed. The retardation value of the twisted nematic liquid crystal layer 12 was set to 1000nm. Unlike the TN-type viewing angle controllers currently on the market, this embodiment uses the Gray second extremum method to maintain the center transmittance without decreasing.

[0054] Figure 5 Images (a) and (b) show the isotransmittance diagrams of the single-layer viewing angle controller 100 of the present invention in normal mode and safe mode, respectively. Image (c) shows the transmittance as a function of polar angle at a 90° azimuth angle. In normal mode, the single-layer viewing angle controller 100 of the present invention maintains high transmittance at all azimuth angles. In safe mode, at a 90° azimuth angle, light leakage at polar angles exceeding 50° is almost eliminated.

[0055] Table 2: Relationship between phase retardation and transmittance of liquid crystals

[0056] Please refer to the table above regarding the relationship between the phase retardation value and transmittance of liquid crystals. Taking a retardation value of 1000nm as a benchmark, when it is less than 1000nm (500nm-800nm), the center transmittance is less than 0.87, and the transmittance at the -80° polar angle is low (less than 0.5), affecting the normal viewing experience for the driver and passenger (the transmittance at the viewing angle is too low, resulting in unclear images). When it is greater than 1000nm, although the center transmittance remains above 0.87, the light leakage at the 80° polar angle becomes increasingly larger (0.139-0.18), which increases the difficulty of compensation. In summary, the range of retardation value can be set at 900nm-1100nm, with 1000nm being the best.

[0057] Table 3: Transmittance of -C membrane, B membrane, and +C membrane at different polar angles under a voltage of 1.6V at a 90° azimuth angle.

[0058] Please refer to Table 3. The reason why +C film is used for compensation and B film (biaxial compensation film) and -C film cannot be used as compensation films for the single-layer viewing angle controller 100 of this invention is: Under a fixed variable of 90° azimuth angle and 1.6V voltage, the compensation effect of -C film is incorrect. Light leakage is not reduced at large polar angles, while the transmittance drops significantly at small polar angles. Light leakage of B film at large polar angles also does not achieve the expected effect. Therefore, +C film is used for compensation. The center transmittance is maintained, and the transmittance at large polar angles is only 0.0062. Example

[0059] like Figure 6 As shown, this is a second embodiment of the viewing angle controller for a car's central display screen and passenger-side display screen according to the present invention. The second embodiment is a single-layer viewing angle controller 200. The difference from the first embodiment is that the polarizer 11 is removed. The reason why the polarizer 11 can be omitted is that the display panel 10000 of the single-layer viewing angle controller 200 has a polarizer (not shown) that can act as a polarizer.

[0060] Example 2 consists of a twisted nematic liquid crystal layer 12, a +C compensation film 13, and an analyzer 14 arranged in sequence. Everything else is the same as in Example 1. Example

[0061] like Figure 7 As shown, this is a third embodiment of the viewing angle controller for a car's central display screen and passenger-side display screen according to the present invention. The third embodiment is a dual-layer viewing angle controller 300, which consists of a polarizer 21, a first layer of twisted nematic liquid crystal layer 22, a first layer of +C compensation film 23, a modulation polarizer 24, a second layer of twisted nematic liquid crystal layer 25, a second layer of +C compensation film 26, and an analyzer 27 arranged in sequence.

[0062] The polarizer 21 is located on the outside of the twisted nematic liquid crystal layer 22.

[0063] The absorption axis of the polarizer 21 is set to 45°.

[0064] The first twisted nematic liquid crystal layer 22 and the second twisted nematic liquid crystal layer 25 are the same as the twisted nematic liquid crystal layer 12 in Embodiment 1, and their delay values ​​are both 1000 nm.

[0065] The first +C compensation film 23 is disposed between the first twisted nematic liquid crystal layer 22 and the modulation polarizer 24.

[0066] The first +C compensation film 23 and the second +C compensation film 26 are the same as the +C compensation film 13 in Example 1, and their retardation values ​​are both 100 nm.

[0067] The absorption axis of the modulation polarizer 24 is set to 135°.

[0068] The second +C compensation film 26 is disposed between the second twisted nematic liquid crystal layer 25 and the analyzer 27.

[0069] The absorption axis of the analyzer 27 is set to 45°.

[0070] like Figure 8 The diagram shows the assembly of the dual-view controller 300 and the display panel 10000 in Embodiment 3. The display panel 10000 is located on the outside of the polarizer 21.

[0071] Since the parameters of the first twisted nematic liquid crystal layer 22 and the second twisted nematic liquid crystal layer 25 are the same, the variation pattern is consistent with the effect of Embodiment 1. Please refer to Table 2 of Embodiment 1 for details.

[0072] Please see Figure 9 The performance of the dual-viewpoint controller 300 in Example 3, which integrates both OLED (Huawei P30) and LCD (iPhone SE2) displays, was simulated and analyzed. Figure 9 As shown, (a) and (b) illustrate the isotransmittance diagrams of the dual-view controller 300 in Embodiment 3 in normal and safe modes, respectively. (c) shows the transmittance variation with polar angle at a 90° azimuth angle. In normal mode, the dual-view controller 300 maintains high transmittance at all azimuth angles. In safe mode, at a 90° azimuth angle, light leakage at polar angles exceeding 40° is almost completely eliminated.

[0073] The transmittance spectra of the dual-view controller 300 at different polar angles (90° and 270° azimuth) were measured using a fiber optic spectrometer. In the experimental setup, the voltage was 0V in normal mode and 1.6V in safety mode. The measurement results are as follows: Figure 10 As shown. Figure 10 Figures (a) and (b) show the transmittance curves for normal and safe modes at a 270° azimuth angle, respectively, while (c) and (d) show the transmittance curves at a 90° azimuth angle. Due to the absorption of the added polarizer, the maximum transmittance is approximately 75%. The results indicate that in normal mode, transmittance remains high within the polar angle range of both azimuth angles, within a range of 60°. In safe mode, transmittance drops to near zero at a polar angle of 35° (90° azimuth angle), while at a lower polar angle (270° azimuth angle), transmittance remains high, similar to that in normal mode.

[0074] To better understand this application, Figure 11 The image showcases the integration of the Dual View Controller 300 with an OLED display (Apple Watch SE). In this configuration, the polarizer in the OLED display has a transmission axis at a 45° azimuth angle. In Normal mode, the Dual View Controller 300 exhibits excellent brightness performance in all directions. In Safe mode, the forward and side views are unaffected, while the upward view achieves complete darkness at a large polar angle, effectively eliminating light projected onto the windshield.

[0075] In Figure 11, (a) normal mode; (b) safe mode; (c) normal mode and safe mode from an upward view. Example

[0076] like Figure 12 As shown, this is a fourth embodiment of the present invention for a viewing angle controller for a central display screen and a passenger-side display screen in an automobile. Embodiment four is a dual-layer viewing angle controller 400, which differs from embodiment three in that the polarizer 21 is removed. The reason why the polarizer 21 can be omitted is that the display panel 10000 of the single-layer viewing angle controller 400 has a polarizer (not shown) that can act as a polarizer.

[0077] Example 4: The dual-viewpoint controller 400 consists of a first layer of twisted nematic liquid crystal layer 22, a first layer of +C compensation film 23, a modulation polarizer 24, a second layer of twisted nematic liquid crystal layer 25, a second layer of +C compensation film 26, and an analyzer 27 arranged sequentially. Everything else is the same as in Example 3. Example

[0078] like Figure 13 As shown, this is a fifth embodiment of the present invention for a viewing angle controller for a car central display screen and a passenger-side display screen. The fifth embodiment is a dual-layer viewing angle controller 500, which differs from the third embodiment in that the first layer +C compensation film 23 is removed.

[0079] Example 5: The dual-viewpoint controller 500 consists of a polarizer 21, a first-layer twisted nematic liquid crystal layer 22, a modulation polarizer 24, a second-layer twisted nematic liquid crystal layer 25, a second-layer +C compensation film 26, and an analyzer 27 arranged in sequence. Everything else is the same as in Example 3. Example

[0080] like Figure 14 As shown, this is a sixth embodiment of the present invention for a viewing angle controller for a car central display screen and a passenger-side display screen. The sixth embodiment is a dual-layer viewing angle controller 600, which differs from the third embodiment in that the polarizer 21 and the first layer +C compensation film 23 are removed.

[0081] Example 6: The dual-viewpoint controller 600 consists of a first layer of twisted nematic liquid crystal layer 22, a modulation polarizer 24, a second layer of twisted nematic liquid crystal layer 25, a second layer of +C compensation film 26, and an analyzer 27 arranged sequentially. Everything else is the same as in Example 3. Example

[0082] like Figure 15 As shown, this is a seventh embodiment of the present invention for a viewing angle controller for a car central display screen and a passenger-side display screen. The seventh embodiment is a dual-layer viewing angle controller 700, which differs from the third embodiment in that the second layer +C compensation film 26 is removed.

[0083] Example 7: The dual-viewpoint controller 700 consists of a polarizer 21, a first twisted nematic liquid crystal layer 22, a first +C compensation film 23, a modulation polarizer 24, a second twisted nematic liquid crystal layer 25, and an analyzer 27 arranged in sequence. Everything else is the same as in Example 3. Example

[0084] like Figure 16 As shown, this is an eighth embodiment of the present invention for a viewing angle controller for a car central display screen and a passenger-side display screen. The eighth embodiment is a dual-layer viewing angle controller 800, which differs from the third embodiment in that the polarizer 21 and the second layer +C compensation film 26 are removed.

[0085] Example 8: The dual-viewpoint controller 800 consists of a first layer of twisted nematic liquid crystal layer 22, a first layer of +C compensation film 23, a modulation polarizer 24, a second layer of twisted nematic liquid crystal layer 25, and an analyzer 27 arranged sequentially. Everything else is the same as in Example 3.

[0086] The present invention further investigates the case where the polarizer absorption axis is not 45° and the analyzer absorption axis is not 135°.

[0087] Table 4: Transmittance values ​​at a fixed azimuth angle of 90° within the range of 35°-55° for the polarizer absorption axis and 125°-145° for the analyzer absorption axis, at a voltage of 1.6V.

[0088] Please refer to Table 4. The polarizer absorption axis is in the range of 35°-55° and the analyzer absorption axis is in the range of 125°-145° (the range of liquid crystal twist angle also changes accordingly, such as: 35° polarizer, 125° analyzer corresponds to liquid crystal twist of 35°-125°). The transmittance value at a fixed azimuth angle of 90° and a voltage of 1.6V is consistent at polar angles of 0°, 80°, and -80° (but the most positive viewing angle is still 45°). Therefore, the effects obtained by setting the polarizer absorption axis to 35° and the analyzer absorption axis to 125°, setting the polarizer absorption axis to 40° and the analyzer absorption axis to 130°, setting the polarizer absorption axis to 50° and the analyzer absorption axis to 150°, and setting the polarizer absorption axis to 55° and the analyzer absorption axis to 145° are the same as the effects obtained by setting the polarizer absorption axis to 45° and the analyzer absorption axis to 135° in Examples 1 to 8.

[0089] The reason for the decrease in transmittance is that this experiment was based on the use of a viewing angle controller that was already attached to the screen, which means that a polarizer was added by default.

[0090] When the polarizer absorption axis angle is A and the analyzer absorption axis is set to B (A=B-90°; A=35°, B=125°; A=40°, B=130°; A=45°, B=135°; A=50°, B=140°; A=55°, B=145°), then the corresponding twisted nematic liquid crystal layer (such as the twisted nematic liquid crystal layer 12 in Examples 1 and 2, and the first twisted nematic liquid crystal layer 22 and the second twisted nematic liquid crystal layer 25 in Examples 3 to 8) includes an upper substrate (not shown) and a lower substrate (not shown) uniformly coated with a polyimide layer to achieve the twisting of liquid crystal molecules. The liquid crystal orientation direction of the lower substrate is changed to A, and the liquid crystal orientation direction of the upper substrate is B. The pretilt angle of both is 2°, and the liquid crystal is twisted from A to B in the layer. In Embodiment 1, the absorption axis angle of the polarizer 11 of the single-layer viewing angle controller 100 is A, and the absorption axis angle of the analyzer 14 is B. In Embodiment 3, the absorption axis angles of the polarizer 21 and the analyzer 27 of the single-layer viewing angle controller 300 are both A, and the absorption axis of the modulation polarizer 24 is set to B.

[0091] For example, when the polarizer absorption axis is set to 35° and the analyzer absorption axis is set to 125°, the corresponding twisted nematic liquid crystal layer (such as the twisted nematic liquid crystal layer 12 in Examples 1 and 2, and the first twisted nematic liquid crystal layer 22 and the second twisted nematic liquid crystal layer 25 in Examples 3 to 8) includes an upper substrate (not shown) and a lower substrate (not shown) uniformly coated with a polyimide layer to achieve the twisting of liquid crystal molecules. The liquid crystal alignment direction of the lower substrate is changed to 35°, the liquid crystal alignment direction of the upper substrate is 125°, and the pretilt angle is 2° for both. The liquid crystal is twisted from 35° to 125° in the layer. Other examples follow the same principle.

[0092] Compared with existing technologies, this invention has the following advantages: This invention provides a viewing angle controller for the central display screen and passenger-side display screen in automobiles, enabling dynamic switching between normal and safe modes, thereby achieving an anti-peeping effect from the upper viewing angle. This invention also solves the problem of light leakage. The core advantage of this invention lies in its ability to intelligently adjust the light transmittance and viewing angle characteristics based on the relative position of the driver and the display screen, ensuring clear vision for the driver while also considering the passenger's viewing experience. This invention is more energy-efficient and cost-effective compared to other viewing angle control methods. This invention can block light from being emitted into the windshield, eliminating virtual images while maintaining high transmittance for both the driver and passenger.

[0093] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A viewing angle controller for a car's central display screen and passenger-side display screen, characterized in that, It consists of a twisted nematic liquid crystal layer (12), a +C compensation film (13), and an analyzer (14) arranged in sequence; The interior of the twisted nematic liquid crystal layer (12) includes an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B. A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V1 of the twisted nematic liquid crystal layer (12) satisfies: 1.2V≤V<1.8V; The range of the retardation value of the twisted nematic liquid crystal layer (12) is set at 900 nm-1100 nm; The absorber axis angle of the analyzer (14) is set to B, where B is 125°, 130°, 135°, 140° or 145°. Therefore, A=35°, B=125° or A=40°, B=130° or A=45°, B=135° or A=50°, B=140° or A=55°, B=145°. The transmittance T1 of the viewing angle controller satisfies 0.2 < T < 0.

76.

2. The viewing angle controller for a car's central display screen and passenger-side display screen according to claim 1, characterized in that, The viewing angle controller for the central display screen and passenger display screen of the car also includes a polarizer (11), which is located outside the twisted nematic liquid crystal layer (12). The absorption axis angle of the polarizer (11) is set to A, and the delay value of the compensation film (13) is 100nm.

3. A viewing angle controller for a car's central display screen and passenger-side display screen, characterized in that, It consists of a first twisted nematic liquid crystal layer (22), a modulation polarizer (24), a second twisted nematic liquid crystal layer (25), a second +C compensation film (26), and an analyzer (27) arranged in sequence; The first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) both include an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B. A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V2 of the first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) satisfies: 1.2V≤V2<1.8V; The range of retardation values ​​for the first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) is set at 900 nm to 1100 nm. The absorption axis angle of the modulation polarizer (24) is set to B; The absorber axis angle of the analyzer (27) is set to A, which is 35°, 40°, 45°, 50° or 55°. Therefore, A=35°, B=125° or A=40°, B=130° or A=45°, B=135° or A=50°, B=140° or A=55°, B=145°. The transmittance T2 of the viewing angle controller satisfies 0.2 < T2 < 0.

76.

4. The viewing angle controller for a car's central display screen and passenger-side display screen according to claim 3, characterized in that, The viewing angle controller for the central display screen and passenger display screen of the car also includes a polarizer (21), which is located outside the first twisted nematic liquid crystal layer (22), and the absorption axis angle of the polarizer (21) is set to A.

5. The viewing angle controller for a central display screen and a passenger-side display screen in an automobile according to claim 3 or 4, characterized in that, The viewing angle controller for the central display screen and passenger display screen of the car also includes a first +C compensation film (23), which is disposed between the first twisted nematic liquid crystal layer (22) and the modulation polarizer (24).

6. The viewing angle controller for a central display screen and a passenger-side display screen in an automobile according to claim 5, characterized in that, The delay values ​​of the first +C compensation film (23) and the second +C compensation film (26) are both 100 nm.

7. A viewing angle controller for a car's central display screen and passenger-side display screen, characterized in that, It consists of a first twisted nematic liquid crystal layer (22), a first +C compensation film (23), a modulation polarizer (24), a second twisted nematic liquid crystal layer (25), and an analyzer (27) arranged in sequence. The first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) both include an upper substrate and a lower substrate. The liquid crystal orientation direction of the lower substrate is A, and the liquid crystal orientation direction of the upper substrate is B. A = B - 90°. The liquid crystal is twisted from A to B in the layer. The driving voltage V3 of the first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) satisfies: 1.2V≤V3<1.8V; The range of retardation values ​​for the first twisted nematic liquid crystal layer (22) and the second twisted nematic liquid crystal layer (25) is set at 900 nm to 1100 nm. The absorption axis angle of the modulation polarizer (24) is set to B; The absorber axis angle of the analyzer (27) is set to A, which is 35°, 40°, 45°, 50° or 55°. Therefore, A=35°, B=125° or A=40°, B=130° or A=45°, B=135° or A=50°, B=140° or A=55°, B=145°. The transmittance T3 of the viewing angle controller satisfies 0.2 < T3 < 0.

76.

8. The viewing angle controller for a car's central display screen and passenger-side display screen according to claim 7, characterized in that, The viewing angle controller for the central display screen and passenger display screen of the car also includes a polarizer (21), which is located outside the first twisted nematic liquid crystal layer (22), and the absorption axis angle of the polarizer (21) is set to A.

9. The viewing angle controller for a central display screen and a passenger-side display screen in an automobile according to claim 7 or 8, characterized in that, The viewing angle controller for the central display screen and passenger display screen of the car also includes a second +C compensation film (26), which is disposed between the second twisted nematic liquid crystal layer (25) and the analyzer (27).

10. The viewing angle controller for a central display screen and a passenger-side display screen in an automobile according to claim 9, characterized in that, The delay values ​​of the first +C compensation film (23) and the second +C compensation film (26) are both 100 nm.

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