Electronic filter and imaging system

Abstract

The invention relates to an electronic filter and an imaging system. The electronic filter comprises a first liquid crystal assembly, a second liquid crystal assembly and a phase difference film arranged between the first liquid crystal assembly and the second liquid crystal assembly, the first liquid crystal assembly comprises a first substrate and a second substrate which are oppositely arranged, and a first liquid crystal layer arranged between the first substrate and the second substrate, and the initial orientation direction of the first liquid crystal layer is parallel to the first substrate; the second liquid crystal assembly comprises a third substrate, a fourth substrate and a second liquid crystal layer, the third substrate and the fourth substrate are oppositely arranged, the second liquid crystal layer is arranged between the third substrate and the fourth substrate, and the initial orientation direction of the second liquid crystal layer is parallel to the third substrate; the initial orientation direction of the first liquid crystal layer and the initial orientation direction of the second liquid crystal layer are parallel and opposite; the phase difference film is configured to enable the polarization direction of light emitted from the first liquid crystal assembly to deflect by 90 degrees so as to be perpendicular to the initial orientation direction of the second liquid crystal layer. The invention also relates to an imaging system.

Description

Technical Field

[0001] The invention relates to the technical field of liquid crystal product manufacturing, and in particular to an electronic filter and an imaging system. Background Art

[0002] When the camera uses a slow shutter speed to record action scenes such as white clouds, flowing water, people and cars, it needs to use an ND filter. Traditional optical neutral density filters are a set of multiple groups of lenses. Depending on the situation on the scene, they need to be frequently replaced and loaded and unloaded. The operation is cumbersome and delays the moment of capturing wonderful pictures. The use of eND filters is quick and intelligent. Traditional optical ND materials mainly include optical glass and polycarbonate (PC). The device has the same and uniform light reduction effect for various wavelengths of light, and will not change the color of the original object, so that the contrast of the scene can be truly reproduced. For eND filters, due to the inherent characteristics of liquid crystal, when there is no power or low voltage, the liquid crystal molecules are tilted. When viewed from different azimuths, sometimes the long axis of the dye molecule is seen, and sometimes the short axis of the dye molecule is seen. The perceived brightness difference is large, which is the so-called dark angle, which affects the photo effect. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an electronic filter and an imaging system to solve the problem of large brightness differences when viewing from different directions.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted in the embodiment of the present invention is: an electronic filter, comprising a first liquid crystal component and a second liquid crystal component sequentially stacked along the light emitting direction, and a phase difference film arranged between the first liquid crystal component and the second liquid crystal component;

[0005] The first liquid crystal assembly comprises a first substrate and a second substrate which are arranged opposite to each other, and a first liquid crystal layer arranged between the first substrate and the second substrate, wherein an initial orientation direction of the first liquid crystal layer is parallel to the first substrate;

[0006] The second liquid crystal assembly comprises a third substrate and a fourth substrate which are arranged opposite to each other, and a second liquid crystal layer arranged between the third substrate and the fourth substrate, wherein the initial alignment direction of the second liquid crystal layer is parallel to the third substrate;

[0007] The initial alignment direction of the first liquid crystal layer is parallel to and opposite to the initial alignment direction of the second liquid crystal layer;

[0008] The phase difference film is configured to deflect the polarization direction of the light emitted from the first liquid crystal component by 90 degrees to be perpendicular to the initial alignment direction of the second liquid crystal layer.

[0009] Optionally, the phase difference film is a 1 / 2 wave plate.

[0010] Optionally, the extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer is 45 degrees.

[0011] Optionally, the phase difference film includes at least one pair of stacked 1 / 4 wave plates.

[0012] Optionally, the phase difference film includes a first pair of 1 / 4 wave plates and a second pair of 1 / 4 wave plates, the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 22.5 degrees, the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 67.5 degrees.

[0013] Optionally, the phase difference film includes a third pair of 1 / 4 wave plates, a fourth pair of 1 / 4 wave plates and a fifth pair of 1 / 4 wave plates, the extension direction of the optical axis of the third pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the third pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 15 degrees, the extension direction of the optical axis of the fourth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the fourth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 45 degrees, the extension direction of the optical axis of the fifth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the fifth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 75 degrees.

[0014] Optionally, the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer is 1.5-5 degrees. The pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer is 1.5-5 degrees.

[0015] Optionally, the cell thickness of the first liquid crystal component is 10-11.5 μm, and the cell thickness of the second liquid crystal component is 10-11.5 μm.

[0016] Optionally, a first alignment film layer is disposed on a side of the first substrate close to the second substrate, and a second alignment film layer is disposed on a side of the second substrate close to the first substrate, and a rubbing direction of the first alignment film layer is the same as a rubbing direction of the second alignment film layer.

[0017] Optionally, a third alignment film layer is disposed on a side of the third substrate close to the fourth substrate, and a fourth alignment film layer is disposed on a side of the fourth substrate close to the third substrate, and a rubbing direction of the third alignment film layer is the same as a rubbing direction of the fourth alignment film layer.

[0018] An embodiment of the present invention further provides a display device, comprising the above-mentioned electronic filter.

[0019] The beneficial effect of the present invention is as follows: the electronic filter provided by the embodiment of the present invention comprises a first liquid crystal component and a second liquid crystal component stacked, wherein the first liquid crystal component comprises a first liquid crystal layer, and the second liquid crystal component comprises a second liquid crystal layer, and the initial orientation direction of the first liquid crystal layer is parallel to and opposite to the initial orientation direction of the second liquid crystal layer. A phase difference film is arranged between the first liquid crystal components, and the phase difference film is configured to deflect the polarization direction of the polarized light emitted from the first liquid crystal component by 90 degrees, so that the polarization direction of the light passing through the phase difference film is perpendicular to the initial orientation direction of the second liquid crystal layer. Thus, the problem of center brightness deviation caused by the initial orientations of the first liquid crystal component and the second liquid crystal component being 90° to each other is solved, that is, the problem of improving the dark angle is improved, and at the same time, light-dark switching can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram showing different viewing angles when no power is applied or the voltage is low;

[0021] Figure 2 Schematic diagram showing viewing from different viewing angles under high voltage state;

[0022] Figure 3 A schematic diagram showing a state in which the initial orientation directions of the liquid crystal layers of two liquid crystal components are perpendicular to each other;

[0023] Figure 4 A schematic diagram showing the simulation results of a radar chart in a first transmittance state (ND4, bright state transmittance is 1 / 4);

[0024] Figure 5 Representation and Figure 4 The corresponding camera actual shooting diagram;

[0025] Figure 6 A schematic diagram showing radar simulation results in the fifth transmittance state (ND64, dark state transmittance is 1 / 64);

[0026] Figure 7 Representation and Figure 6 The corresponding camera actual shooting diagram;

[0027] Figure 8 A schematic diagram showing the WV membrane is set and in the fifth transmittance state;

[0028] Fig. 9 A schematic diagram showing the principle of displaying a dark state when no power is supplied;

[0029] Fig.10 A schematic diagram showing the principle of the display being bright in the power-on state;

[0030] Fig.11 Schematic diagram showing the vibration directions of o-light and e-light in the initial state;

[0031] Fig.12 Schematic diagram showing the vibration directions of o-light and e-light after passing through the half-wave plate;

[0032] Fig.13 A schematic diagram showing that the initial orientation directions of the liquid crystal layers of two liquid crystal components in the related art are perpendicular to each other;

[0033] Fig.14 A schematic diagram showing that the initial alignment direction of the first liquid crystal layer and the initial alignment direction of the second liquid crystal layer are anti-parallel after adding a phase difference film in an embodiment of the present invention;

[0034] Fig.15 A schematic diagram showing that the initial alignment direction of the first liquid crystal layer and the initial alignment direction of the second liquid crystal are parallel but not opposite;

[0035] Fig.16 A schematic diagram showing that the initial alignment direction of the first liquid crystal layer and the initial alignment direction of the second liquid crystal are parallel but opposite;

[0036] Fig.17 Indicates the use of Fig.15 Schematic diagram of the radar at the first transmittance (ND4, bright state transmittance is 1 / 4) under the structure;

[0037] Fig.18 Indicates the use of Fig.15 Schematic diagram of the radar at the fifth transmittance (ND64, dark state transmittance is 1 / 64) under the structure;

[0038] Fig.19 Indicates the use of Fig.16 Schematic diagram of radar at the first transmittance under the structure of;

[0039] Fig. 20 Indicates the use of Fig.16 Schematic diagram of radar at the fifth transmittance under the structure of;

[0040] Fig.21 Indicates that it corresponds to Fig.19 Schematic diagram of the camera shot;

[0041] Fig. 22 Indicates that it corresponds to Fig. 20 Schematic diagram of the camera shot;

[0042] Fig.23 A schematic diagram showing the color shift simulation result when the phase difference film is a 1 / 2 wave plate;

[0043] Fig.24 A curve showing how the refractive index of liquid crystal decreases as the wavelength of light increases;

[0044] Fig.25 The curve showing the change in phase delay of the 1 / 2 positive dispersion wave plate as the wavelength of light increases;

[0045] Fig.26 The curve showing the change of the phase delay of the 1 / 4 inverse dispersion wave plate as the wavelength of light increases;

[0046] Fig. 27 A schematic diagram showing the color shift simulation results of a phase difference film using four layers of 1 / 4 reverse dispersion wave plates (i.e., a first pair of 1 / 4 wave plates and a second pair of 1 / 4 wave plates);

[0047] Fig.28 A schematic diagram showing the color shift simulation results of a phase difference film using 6 layers of 1 / 4 reverse dispersion wave plates (i.e., the third pair of 1 / 4 wave plates, the fourth pair of 1 / 4 wave plates, and the fifth pair of 1 / 4 wave plates);

[0048] Fig.29 A schematic diagram showing the radar chart simulation results at the first transmittance using 4 layers of 1 / 4 inverse dispersion wave plates;

[0049] Fig.30 A schematic diagram showing the results of radar chart simulation at the fifth transmittance using 4 layers of 1 / 4 inverse dispersion wave plates;

[0050] Fig.31 A schematic diagram showing the radar chart simulation results at the first transmittance using 6 layers of 1 / 4 inverse dispersion wave plates;

[0051] Fig.32 A schematic diagram showing the results of radar chart simulation at the fifth transmittance using 6 layers of 1 / 4 reverse dispersion wave plates;

[0052] Fig.33 A schematic diagram showing the color deviation simulation results when the pre-tilt angle is 1.5 degrees and the phase difference film uses a 1 / 4 reverse dispersion wave plate;

[0053] Fig.34 A schematic diagram showing the color shift simulation results when a lower cell thickness is selected and the phase difference film uses a 1 / 4 reverse dispersion wave plate;

[0054] Fig.35 A schematic diagram showing the color shift simulation results when the pre-tilt angle is 1.5 degrees and a relatively low cell thickness is selected, and the phase difference film uses a 1 / 4 reverse dispersion wave plate;

[0055] Fig.36 A schematic diagram showing the color shift simulation results when the pre-tilt angle is 1.5 degrees and a relatively low cell thickness is selected, and the phase difference film uses a 1 / 6 reverse dispersion wave plate;

[0056] Fig.37 A schematic diagram showing that the electronic filter has four liquid crystal components;

[0057] Fig.38 A schematic diagram showing a radar chart simulation result at a second transmittance (ND8, 1 / 8 transmittance) when the electronic filter includes a first liquid crystal component, a second liquid crystal component, a third liquid crystal component and a fourth liquid crystal component that are stacked;

[0058] Fig.39 A schematic diagram showing a radar chart simulation result at a fifth transmittance (ND64, dark state 1 / 64 transmittance) when the electronic filter includes a first liquid crystal component, a second liquid crystal component, a third liquid crystal component and a fourth liquid crystal component that are stacked;

[0059] Fig.40 A schematic diagram showing the angles of the transmission axes of the two pairs of quarter wave plates included in the retardation film;

[0060] Fig.41 A schematic diagram showing the angles of the transmission axes of the three pairs of quarter-wave plates included in the retardation film. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0062] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0063] The features such as "parallel", "perpendicular", and "same" used in the embodiments of the present disclosure include the features such as "parallel", "perpendicular", and "same" in a strict sense, as well as the cases where "approximately parallel", "approximately perpendicular", "approximately the same", etc. include certain tolerances, taking into account the tolerances associated with the measurement of specific quantities (e.g., the limitations of the measurement system), and represent the acceptable deviation range for a specific value determined by ordinary technicians in the field. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of the value.

[0064] In addition, in this document, unless otherwise defined, the terms "substantially", "substantially", "approximately" and "about" are used to describe and explain small changes. When used with an event or situation, these terms can cover situations where the event or situation occurs exactly, and can also cover situations where the event or situation occurs approximately. For example, when used with a numerical value, these terms can include a range of variation of less than or equal to 10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, less than or equal to ±0.05%. The term "substantially coplanar" can refer to two surfaces being arranged along the same plane in the micrometer range, for example, arranged along the same plane within 40μm, 30μm, 20μm, 10μm or 1μm.

[0065] In the related art, the electronic filter includes two stacked liquid crystal components, each of which includes two oppositely disposed substrates and a liquid crystal layer disposed between the two substrates. The liquid crystal layer contains liquid crystal molecules and dye molecules, which interact with each other and jointly affect the transmission and polarization of light. When the two liquid crystal components are not powered on, the liquid crystal molecules in the two liquid crystal components are perpendicular to each other, and the light is absorbed by the dye molecules, that is, the light cannot pass through the electronic filter, making the electronic filter dark. When the two liquid crystal components are powered on, the liquid crystal molecules in the two liquid crystal components rotate or tilt under the action of the electric field. If the liquid crystal molecules are both in a vertical state, the light passes through, making the electronic filter white.

[0066] Figure 1 Schematic diagram of viewing from different angles when not powered or in low voltage state. Figure 2 Schematic diagram of viewing at different viewing angles under high voltage state. Due to the inherent characteristics of liquid crystal, when no power is applied or the voltage is low, the liquid crystal molecules are arranged at an angle. When viewed at different azimuth angles, the refractive index difference of the dye molecules 102 is different, and the perceived brightness difference is large. Under high voltage state, the liquid crystal molecules 101 tend to be arranged vertically. Under the same oblique viewing angle, when viewed at different azimuth angles, the arrangement state of the dye molecules 102 tends to be consistent, and the perceived brightness difference is small. Therefore, the darker the state, the more obvious the dark angle.

[0067] Figure 3 It is a schematic diagram showing a state in which the initial orientation directions of the liquid crystal layers of two liquid crystal components are perpendicular to each other. Figure 3 The long arrows on the first liquid crystal component 1 and the second liquid crystal component 2 indicate the initial alignment direction of the liquid crystal layer, and the short arrows on the first liquid crystal component 1 and the second liquid crystal component 2 indicate the tilt direction of the liquid crystal molecules. Figure 4 Schematic diagram of radar simulation results in the first transmittance state (ND4, bright state transmittance is 1 / 4), Figure 5 For Figure 4 The corresponding camera actual shooting diagram. Figure 6 is a schematic diagram of radar simulation results in the fifth transmittance state (ND64, dark state transmittance is 1 / 64), Figure 7 For Figure 6 The corresponding camera actual shooting diagram.

[0068] The initial orientation directions of the liquid crystal layers of the two liquid crystal components are perpendicular to each other, so the pre-tilt angles of the liquid crystal molecules in the liquid crystal layers of the two liquid crystal components are also perpendicular. The brightness at the beginning of the pre-tilt intersection is darker, and a dark angle appears. The dark angle is more obvious in the dark state, and the simulation matches the actual measurement. Figure 4 The red part is the area with higher brightness, which is basically in the center and has a small deviation. The brightness of the yellow area, green area and blue area set from the center to the outside gradually decreases. Figure 4 and Figure 6 The simulation diagram shows that as the transmittance decreases, the red part of the light with the highest brightness gradually shifts to the edge, and the brightness shift is tilted toward the upper right along the dotted line. As the transmittance decreases, the brightness difference at the opposite ends of the dotted line gradually increases. Figure 5 and Figure 7 In the actual camera shooting diagram, as the transmittance decreases, the brightness shifts, and the shift direction corresponds to the simulation diagram. The lower the transmittance, the more obvious the vignetting.

[0069] In order to improve the vignetting in the related art, a viewing angle compensation film (WV film & NH film & A+C compensation film) is used. However, because the WV film & A+C compensation film are both symmetrical compensation films and can only compensate for one of the two liquid crystal components, the brightness range can be expanded to compensate for the viewing angle brightness, but the asymmetry cannot be calibrated to symmetry. In other words, there is still a problem of large brightness difference when viewing from two relative positions, and the improvement of vignetting is limited. Figure 8 , Figure 8 This is a schematic diagram of a WV film at the fifth transmittance (ND64, transmittance 1 / 64). Figure 6 By setting the WV film, the brightness range is expanded to compensate for the viewing angle brightness, but Figure 8 There is still a brightness difference on the opposite sides (lower left corner and upper right corner) of the direction of the inclined straight line.

[0070] In view of the above problems, an embodiment of the present invention provides an electronic filter, comprising a first liquid crystal component 1 and a second liquid crystal component 2 sequentially stacked along a light emitting direction, and a phase difference film arranged between the first liquid crystal component 1 and the second liquid crystal component 2;

[0071] The first liquid crystal assembly 1 comprises a first substrate 11 and a second substrate 12 which are arranged opposite to each other, and a first liquid crystal layer 13 arranged between the first substrate 11 and the second substrate 12, wherein the initial orientation direction of the first liquid crystal layer 13 is parallel to the first substrate 11;

[0072] The second liquid crystal assembly 2 comprises a third substrate 21 and a fourth substrate 22 which are arranged opposite to each other, and a second liquid crystal layer 23 arranged between the third substrate 21 and the fourth substrate 22, wherein the initial orientation direction of the second liquid crystal layer 23 is parallel to the third substrate 21;

[0073] The initial alignment direction of the first liquid crystal layer 13 is parallel to and opposite to the initial alignment direction of the second liquid crystal layer 23;

[0074] The phase difference film is configured to deflect the polarization direction of the light emitted from the first liquid crystal component 1 by 90 degrees so as to be perpendicular to the initial alignment direction of the second liquid crystal layer 23 .

[0075] Due to the effect of the pre-tilt angle, the refractive index difference of the dye molecules in the liquid crystal layer is different when viewed at different azimuth angles, and the perceived brightness difference is large. In addition, the pre-tilt angles of the liquid crystal molecules in the liquid crystal layer of another liquid crystal component in the related art are perpendicular to each other, resulting in a central brightness shift. In this embodiment, the initial orientation direction of the liquid crystal molecules in the first liquid crystal layer 13 of the first liquid crystal component 1 and the initial orientation direction of the liquid crystal molecules in the second liquid crystal layer 23 of the second liquid crystal component 2 are set to be parallel and opposite, that is, the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer 13 of the first liquid crystal component 1 and the pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer 23 of the second liquid crystal component 2 are set to be parallel and opposite, so that the offset of the light passing through the first liquid crystal layer 13 and the offset of the light passing through the second liquid crystal layer 23 can be exactly offset, thereby solving the problem of brightness difference at different viewing angles and improving the dark angle problem.

[0076] In this embodiment, a phase difference film 3 is arranged between the first liquid crystal component 1 and the second liquid crystal component 2, and the phase difference film 3 is configured to deflect the polarization direction of the polarized light emitted from the first liquid crystal component 1 by 90 degrees, so that the polarization direction of the light passing through the phase difference film 3 is perpendicular to the direction of the light transmission axis of the second liquid crystal, so that the switching between the bright state and the dark state can be achieved. Fig. 9 and Fig.10 , Fig. 9 It is a schematic diagram of the principle of displaying a dark state when no power is applied. Fig.10 This is a schematic diagram showing the principle of bright display when powered on. Fig. 9 , the initial orientation direction of the first liquid crystal layer 13 and the initial orientation direction of the second liquid crystal layer 23 are anti-parallel, and the initial orientation direction of the first liquid crystal layer 13 and the initial orientation direction of the second liquid crystal layer 23 are parallel to the plane where the first substrate 11 (the first substrate 11, the second substrate 12, the third substrate 21 and the fourth substrate 22 are arranged parallel to each other), the light becomes polarized light after passing through the first liquid crystal component 1, and the polarization direction is 90 degrees, and then the light after passing through the phase difference film 3 is deflected 90 degrees, and the polarization direction is 0 degrees, which is perpendicular to the light transmission axis of the liquid crystal layer of the second liquid crystal component 2, and the light cannot pass through, and it is displayed as a dark state. Reference Fig.10In the powered state, the liquid crystal molecules of the first liquid crystal layer 13 are deflected and arranged perpendicularly to the first substrate 11, and the liquid crystal molecules of the second liquid crystal layer 23 are deflected and arranged perpendicularly to the first substrate 11. The light passes through the first liquid crystal component 1 and becomes polarized light with a polarization direction of 0 degrees, and then passes through the phase difference film 3 and becomes polarized light with a polarization direction of 90 degrees. Then, after passing through the second liquid crystal component 2, it is not absorbed by the dye molecules in the second liquid crystal layer 23, that is, it passes through the second liquid crystal component 2 and is displayed in a white state.

[0077] It should be noted that the light becomes linearly polarized light after passing through the first liquid crystal component 1 , and then remains linearly polarized light after passing through the phase difference film 3 .

[0078] Exemplarily, both the first liquid crystal layer and the second liquid crystal layer are electrically controlled birefringence (English: Electrically Controlled Birefringence; ECB for short) liquid crystal layers.

[0079] In this embodiment, the initial alignment direction of the first liquid crystal layer 13 and the initial alignment direction of the second liquid crystal layer 23 are set to be parallel and opposite (i.e., anti-parallel), the pre-tilt angle of the liquid crystal molecules of the first liquid crystal layer 13 and the pre-tilt angle of the liquid crystal molecules of the second liquid crystal layer 23 are the same, but the tilt direction of the liquid crystal molecules of the first liquid crystal layer 13 and the tilt direction of the liquid crystal molecules of the second liquid crystal layer 23 are parallel and opposite. It can also be understood that the liquid crystal molecules of the first liquid crystal layer 13 and the liquid crystal molecules of the second liquid crystal layer 23 are mirror-symmetrical with respect to the plane where the first substrate 11 is located, reducing the brightness difference at different viewing angles and improving the dark angle. .

[0080] In an exemplary embodiment, the phase difference film 3 is a 1 / 2 wave plate.

[0081] Working principle of 1 / 2λ wave plate: e-light (extraordinary light) will change its phase by π times, that is, 1 / 2 period, when it passes through 1 / 2λ wave plate. Fig.11 and Fig.12 , Fig.11 Schematic diagram of the vibration direction of o-light and e-light in the initial state. Fig.12 Schematic diagram showing the vibration direction of o-light and e-light after passing through a half-wave plate. If the initial vibration directions of o-light (ordinary light) and e-light are along the positive direction of the x-axis and the positive direction of the y-axis respectively, then after passing through a 1 / 2λ wave plate, the e-light changes its phase by π, which is equivalent to advancing half a cycle. At this time, the new polarization directions of o-light and e-light are respectively in the positive direction of the x-axis and the negative direction of the y-axis. Therefore, after passing through a 1 / 2λ wave plate, the vibration direction will rotate by 2 times the optical axis ( Fig.11 and Fig.12 The orange arrow in the figure is the angle between the optical axis and the beam.

[0082] Exemplarily, the extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer 13 are located in the same plane, and the angle between the extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer 13 is 45 degrees.

[0083] By adopting the above scheme, the polarization direction of the light can be rotated 90 degrees, so that the polarization direction of the light after passing through the 1 / 2 wave plate can be perpendicular to the initial orientation direction of the second liquid crystal layer 23, that is, the initial orientation direction of the first liquid crystal layer 13 and the initial orientation direction of the second liquid crystal are parallel, and the conversion between bright state and dark state can be realized. Fig.13 is a schematic diagram of the initial orientation directions of the liquid crystal layers of two liquid crystal components in the related art being perpendicular to each other, Fig.14 A schematic diagram showing that the initial alignment direction of the first liquid crystal layer 13 and the initial alignment direction of the second liquid crystal layer 23 are anti-parallel after the phase difference film 3 is added in the embodiment of the present invention.

[0084] Fig.15 It is a schematic diagram showing that the initial alignment direction of the first liquid crystal layer 13 and the initial alignment direction of the second liquid crystal are parallel but not opposite. Fig.15 The long arrows on the first liquid crystal component 1 and the second liquid crystal component 2 represent the initial alignment directions of the corresponding liquid crystal layers, and the short arrows on the first liquid crystal component 1 and the second liquid crystal component 2 represent the tilt directions of the corresponding liquid crystal molecules. Fig.16 It is a schematic diagram showing that the initial alignment direction of the first liquid crystal layer 13 and the initial alignment direction of the second liquid crystal are parallel but opposite. Fig.16 The long arrows on the first liquid crystal component 1 and the second liquid crystal component 2 represent the initial alignment directions of the corresponding liquid crystal layers, and the short arrows on the first liquid crystal component 1 and the second liquid crystal component 2 represent the tilt directions of the corresponding liquid crystal molecules. Fig.17 To adopt Fig.15 Schematic diagram of the radar at the first transmittance (ND4, bright state transmittance is 1 / 4) under the structure. Fig.18 To adopt Fig.15 Schematic diagram of the radar at the fifth transmittance (ND64, dark state transmittance is 1 / 64) under the structure. Fig.19 To adopt Fig.16 Schematic diagram of the radar at the first transmittance under the structure of Fig. 20 To adopt Fig.16 Schematic diagram of the radar at the fifth transmittance under the structure of Fig.21 Indicates that it corresponds to Fig.19 Schematic diagram of the camera shot. Fig. 22 Indicates that it corresponds to Fig. 20 Schematic diagram of the camera's actual shooting.

[0085] Will Fig.17 and Fig.19 To compare, Fig.18 and Fig. 20 By comparison, it is obvious that Fig.16 The structure shown, that is, the initial orientation direction of the first liquid crystal layer 13 and the initial orientation direction of the second liquid crystal layer 23 are set to be reversely parallel, and a phase difference film 3 is added between the first liquid crystal component 1 and the second liquid crystal component 2, so that the display brightness tends to be centrally symmetrical, reduces the brightness difference in two relative directions, improves the brightness center offset, and improves the dark corner phenomenon. Fig.21 and Fig. 22 The actual camera shooting diagram also verifies that the above scheme can reduce the brightness difference in different observation directions and improve the dark corners.

[0086] The 1 / 2λ wave plate is mainly used to deflect the light in the 550nm band by 2 times the angle. The deflection angle of red light and blue light cannot reach 2 times the angle completely. Therefore, red light and blue light will leak out in the dark state, resulting in color deviation. Fig.23 , Fig.23 The figure is a schematic diagram of the color deviation simulation result when the phase difference film 3 is a 1 / 2 wave plate. In addition, the phase delay of the dye liquid crystal is different at different viewing angles. Therefore, the sample will show a large viewing angle color deviation. In order to balance the relationship between dark angle and color deviation, the liquid crystal design and the phase difference film 3 need to be matched.

[0087] Since the liquid crystal material has a positive dispersion distribution, in order to reduce the color deviation, it is necessary to select a reverse dispersion wave plate to compensate and balance the color deviation. Currently, the phase difference film 3 that can be mass-produced is mainly divided into positive dispersion (positive dispersion) and reverse dispersion (reverse dispersion) phase difference film 3. Positive dispersion means that R0 (phase delay) decreases with the increase of wavelength, while reverse dispersion means that R0 increases with the increase of wavelength. Fig.24 This is the curve showing that the refractive index of liquid crystal decreases as the wavelength of light increases. Fig.25 This is the curve of the phase delay reduction of the 1 / 2 positive dispersion wave plate as the wavelength of light increases ( Fig.25 The figure shows the variation curves of three 1 / 2 positive dispersion wave plates with different phase difference values ​​(curve 100 represents a 1 / 2 positive dispersion wave plate with a phase difference value of 277, curve 200 represents a 1 / 2 positive dispersion wave plate with a phase difference value of 270, and curve 300 represents a 1 / 2 positive dispersion wave plate with a phase difference value of 260). Fig.26 This is the curve showing the phase delay of the 1 / 4 inverse dispersion wave plate increasing with the increase of the wavelength of the light.

[0088] In an exemplary embodiment, the phase difference film 3 includes at least one pair of stacked 1 / 4 reverse dispersion wave plates.

[0089] Exemplarily, the phase difference film 3 includes a first pair of 1 / 4 wave plates and a second pair of 1 / 4 wave plates, the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 are located in the same plane, and the angle a between the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 is 22.5 degrees, the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 are located in the same plane, and the angle b between the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 is 67.5 degrees, with reference to Fig.40 , the horizontal dotted line in the figure is the optical axis.

[0090] Fig. 27 A schematic diagram showing the color shift simulation results of the phase difference film 3 using four layers of 1 / 4 reverse dispersion wave plates (i.e., the first pair of 1 / 4 wave plates and the second pair of 1 / 4 wave plates). Fig.23 In contrast, the color cast is significantly improved.

[0091] Exemplarily, the phase difference film 3 includes a third pair of 1 / 4 wave plates, a fourth pair of 1 / 4 wave plates and a fifth pair of 1 / 4 wave plates, the angle c between the extension direction of the optical axis of the third pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 is 15 degrees, the angle d between the extension direction of the optical axis of the fourth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 is 45 degrees, and the angle e between the extension direction of the optical axis of the fifth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer 13 is 75 degrees. Fig.41 , the horizontal dotted line in the figure is the optical axis.

[0092] Fig.28 A schematic diagram showing the color shift simulation results of the phase difference film 3 using 6 layers of 1 / 4 reverse dispersion wave plates (i.e., the third pair of 1 / 4 wave plates, the fourth pair of 1 / 4 wave plates, and the fifth pair of 1 / 4 wave plates). Fig.23 In contrast, the color cast has been significantly improved. Fig.28 and Fig. 27 By comparison, the phase difference film 3 using 6 layers of 1 / 4 reverse dispersion wave plates has a better effect on improving color deviation than the phase difference film 3 using 4 layers of 1 / 4 reverse dispersion wave plates.

[0093] Fig.29 This is a schematic diagram of the radar chart simulation results under the first transmittance using 4 layers of 1 / 4 reverse dispersion wave plates. Fig.30 Schematic diagram of radar chart simulation results at the fifth transmittance using 4 layers of 1 / 4 inverse dispersion wave plates. Fig.31 This is a schematic diagram of the radar chart simulation results under the first transmittance using 6 layers of 1 / 4 reverse dispersion wave plates. Fig.32This is a schematic diagram of the radar chart simulation results at the fifth transmittance using 6 layers of 1 / 4 reverse dispersion wave plates. Fig.29 and Fig.31 For comparison, Fig.30 and Fig.32 In comparison, the phase difference film 3 uses a 6-layer 1 / 4 reverse dispersion wave plate, which has a better effect of improving the dark angle.

[0094] Principle of multi-layer reverse dispersion film: Utilize the property that the refractive index value of reverse dispersion material increases with the increase of wavelength, compensate for the refractive index change caused by the change of wavelength of dye liquid crystal, and make the phase delay of each band of light after passing through the entire product the same through compensation, thereby improving the light leakage of different wavelengths of light in the dark state with a large viewing angle. The number of layers of reverse dispersion wave plates is mainly used to adjust the refractive index, wherein every two layers of 1 / 4λ reverse dispersion wave plates form a 1 / 2λ wave plate, which deflects the light by 2 times the angle. In this embodiment, by designing the angle of the optical axis of the wave plate, the polarized light formed by the first liquid crystal component 1 finally deflects the polarization angle by 90° after passing through the phase difference film 3, realizing the switching between bright and dark states. It should be noted that the number of 1 / 4λ reverse dispersion wave plates, different angles, reverse dispersion wave plates of different wavelengths, and different rubbing (rubbing orientation) angles (i.e., the initial orientation direction of the liquid crystal layer) all affect the dark angle and color shift effects, and need to be matched according to actual needs.

[0095] In an exemplary embodiment, the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer 13 is 1.5-5 degrees, for example, 1.5 degrees. The pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer 23 is 1.5-5 degrees, for example, 1.5 degrees.

[0096] The conventional setting of the pre-tilt angle of the liquid crystal molecules is 5 degrees. In this embodiment, the pre-tilt angle of the liquid crystal molecules of the liquid crystal layer is reduced, that is, the pre-tilt angle of the liquid crystal molecules is set to less than 5 degrees, and the phase delay amount of the liquid crystal layer in the initial state is reduced, so that it is more matched with the phase delay film of the reverse dispersion, which is conducive to improving symmetry and optimizing color deviation. It should be noted that if the pre-tilt angle of the liquid crystal molecules is reduced, it is necessary to increase the polarization voltage of the liquid crystal and increase power consumption. Therefore, in order to avoid excessive increase in power consumption, in some embodiments, the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer 13 is less than 5 degrees and greater than or equal to 1.5 degrees. The pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer 23 is less than 5 degrees and greater than or equal to 1.5 degrees. Fig.33 The schematic diagram of the color deviation simulation result of the phase difference film 3 using a 1 / 4 reverse dispersion wave plate with a pre-tilt angle of 1.5 degrees is shown in FIG. Fig. 27 For comparison, the color cast was further optimized.

[0097] Exemplarily, the cell thickness of the first liquid crystal component is 10-11.5 μm, and / or the cell thickness of the second liquid crystal component is 10-11.5 μm.

[0098] It should be noted that in order to meet the transmittance of ND4 (bright state, transmittance of 1 / 4)-ND64 (dark state, transmittance of 1 / 64), the cell thickness of the first liquid crystal component or the cell thickness of the second liquid crystal component needs to be set to be above 10μm. In this embodiment, on the basis of meeting the required transmittance, the cell thickness of the first liquid crystal component is 10-11.5μm, and / or the cell thickness of the second liquid crystal component is 10-11.5μm. That is, by selecting a lower cell thickness of the first liquid crystal component and / or selecting a lower cell thickness of the second liquid crystal component to adjust the matching of the liquid crystal layer and the reverse dispersion phase delay film, the initial state compensation effect is better, and it is beneficial to the color shift simulation result. Fig.34 Schematic diagram of color shift simulation results of the phase difference film 3 using a 1 / 4 reverse dispersion wave plate after selecting a lower cell thickness (the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer 13 is 1.5 degrees, and the pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer 23 is 1.5 degrees), and Fig. 27 For comparison, the color cast was further optimized.

[0099] It should be noted that the cell thickness of the first liquid crystal component and the cell thickness of the second liquid crystal component may be the same or different, but the cell thickness of the first liquid crystal component and the cell thickness of the second liquid crystal component are both 10-11.5 μm to effectively improve color deviation.

[0100] Exemplarily, the pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer 13 is reduced from the conventional 5 degrees to 1.5 degrees, and the pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer 23 is reduced from the conventional 5 degrees to 1.5 degrees, and the thickness of the first liquid crystal layer 13 is 10-11.5 μm, and the thickness of the second liquid crystal layer 23 is 10-11.5 μm. That is, while reducing the pre-tilt angle of the liquid crystal layer, a lower thickness of the liquid crystal layer is selected. Fig.35 Schematic diagram showing the color shift simulation results of the phase difference film 3 using a 1 / 4 reverse dispersion wave plate after reducing the pre-tilt angle and selecting a lower cell thickness, and Fig. 27 For comparison, the color cast was further optimized. Fig.36 Schematic diagram showing the color shift simulation results of the phase difference film 3 using a 1 / 6 reverse dispersion wave plate after reducing the pre-tilt angle and selecting a lower cell thickness, and Fig.28 By comparison, the color coordinate transformation range is small, which further optimizes the color deviation (the more uniform the color, the better the display effect, Fig.28 The color of the lower middle area is darker than that of other areas, that is, the color difference is large. Fig.36 The colors of the various areas are more uniform).

[0101] refer to Fig.37In some embodiments, the electronic filter includes a stacked first liquid crystal component 1, a second liquid crystal component 2, a third liquid crystal component 4 and a fourth liquid crystal component 5, so that the pretilt angles in the two directions can offset each other, and each ND is a concentric circle with the highest symmetry.

[0102] It should be noted that Fig.37 In the figure, the initial orientation direction of the liquid crystal layer of the first liquid crystal component 1 is parallel to the initial orientation direction of the liquid crystal layer of the fourth liquid crystal component 5 (the long arrows on the first liquid crystal component 1 and the fourth liquid crystal component 5 indicate the corresponding initial orientation directions), the pretilt angles of the liquid crystal molecules of the first liquid crystal component 1 are the same as the pretilt angles of the liquid crystal molecules of the fourth liquid crystal component 5, and the tilt directions are opposite (the short arrows on the first liquid crystal component 1 and the fourth liquid crystal component 5 indicate the corresponding tilt directions of the liquid crystal molecules), the initial orientation direction of the liquid crystal layer of the second liquid crystal component 2 is parallel to the initial orientation direction of the liquid crystal layer of the third liquid crystal component 4 (the long arrows on the second liquid crystal component 2 and the third liquid crystal component 4 indicate the corresponding initial orientation directions), the pretilt angles of the liquid crystal molecules of the second liquid crystal component 2 are the same as the pretilt angles of the liquid crystal molecules of the third liquid crystal component 4, and the tilt directions are opposite (the short arrows on the second liquid crystal component 2 and the third liquid crystal component 4 indicate the corresponding tilt directions of the liquid crystal molecules). It should be noted that the stacking order of the first liquid crystal component 1, the second liquid crystal component 2, the third liquid crystal component 4 and the fourth liquid crystal component 5 is not limited to the above description.

[0103] Fig.38 A schematic diagram showing a radar chart simulation result at a second transmittance (ND8, 1 / 8 transmittance) when the electronic filter includes a first liquid crystal component 1, a second liquid crystal component 2, a third liquid crystal component 4 and a fourth liquid crystal component 5 stacked together, Fig.38 and Fig.19 contrast, Fig.38 The display is more uniform. Fig.39 A schematic diagram showing a radar chart simulation result at a fifth transmittance (ND64, 1 / 64 transmittance) when the electronic filter includes a first liquid crystal component 1, a second liquid crystal component 2, a third liquid crystal component 4 and a fourth liquid crystal component 5 stacked together, Fig.39 and Figure 6 For comparison, Fig.39 The display is more uniform, and it can be seen that the increase in the number of superimposed liquid crystal components can improve the color deviation.

[0104] Exemplarily, a first alignment film layer is disposed on a side of the first substrate 11 close to the second substrate 12, and a second alignment film layer is disposed on a side of the second substrate 12 close to the first substrate 11, and a rubbing direction of the first alignment film layer is the same as a rubbing direction of the second alignment film layer.

[0105] Exemplarily, a third alignment film layer is disposed on a side of the third substrate 21 close to the fourth substrate 22, and a fourth alignment film layer is disposed on a side of the fourth substrate 22 close to the third substrate 21, and the rubbing direction of the third alignment film layer is the same as the rubbing direction of the fourth alignment film layer.

[0106] An embodiment of the present invention further provides a display device, comprising the above-mentioned electronic filter.

[0107] There are a few points to note:

[0108] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0109] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0110] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0111] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An electronic filter, characterized in that: It includes a first liquid crystal component and a second liquid crystal component which are sequentially stacked along the light emitting direction, and a phase difference film arranged between the first liquid crystal component and the second liquid crystal component; The first liquid crystal assembly comprises a first substrate and a second substrate which are arranged opposite to each other, and a first liquid crystal layer arranged between the first substrate and the second substrate, wherein an initial orientation direction of the first liquid crystal layer is parallel to the first substrate; The second liquid crystal assembly comprises a third substrate and a fourth substrate which are arranged opposite to each other, and a second liquid crystal layer arranged between the third substrate and the fourth substrate, wherein the initial alignment direction of the second liquid crystal layer is parallel to the third substrate; The initial alignment direction of the first liquid crystal layer is parallel to and opposite to the initial alignment direction of the second liquid crystal layer; The phase difference film is configured to deflect the polarization direction of the light emitted from the first liquid crystal component by 90 degrees to be perpendicular to the initial alignment direction of the second liquid crystal layer.

2. The electronic filter according to claim 1, characterized in that: The phase difference film is a 1 / 2 wave plate.

3. The electronic filter according to claim 2, characterized in that: The extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the 1 / 2 wave plate and the alignment direction of the first liquid crystal layer is 45 degrees.

4. The electronic filter according to claim 1, characterized in that: The phase difference film includes at least a pair of stacked quarter wave plates.

5. The electronic filter according to claim 4, characterized in that: The phase difference film includes a first pair of 1 / 4 wave plates and a second pair of 1 / 4 wave plates, the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the first pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 22.5 degrees, the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the second pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 67.5 degrees.

6. The electronic filter according to claim 4, characterized in that: The phase difference film includes a third pair of 1 / 4 wave plates, a fourth pair of 1 / 4 wave plates and a fifth pair of 1 / 4 wave plates. The extension direction of the optical axis of the third pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the third pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 15 degrees. The extension direction of the optical axis of the fourth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the fourth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 45 degrees. The extension direction of the optical axis of the fifth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer are located in the same plane, and the angle between the extension direction of the optical axis of the fifth pair of 1 / 4 wave plates and the orientation direction of the first liquid crystal layer is 75 degrees.

7. The electronic filter according to claim 1, characterized in that: The pre-tilt angle of the liquid crystal molecules in the first liquid crystal layer is 1.5-5 degrees, and the pre-tilt angle of the liquid crystal molecules in the second liquid crystal layer is 1.5-5 degrees.

8. The electronic filter according to claim 1, characterized in that: The cell thickness of the first liquid crystal component is 10-11.5 μm, and the cell thickness of the second liquid crystal component is 10-11.5 μm.

9. The electronic filter according to claim 1, characterized in that: A first alignment film layer is disposed on a side of the first substrate close to the second substrate, and a second alignment film layer is disposed on a side of the second substrate close to the first substrate. The rubbing direction of the first alignment film layer is the same as the rubbing direction of the second alignment film layer.

10. The electronic filter according to claim 1, characterized in that: A third alignment film layer is disposed on a side of the third substrate close to the fourth substrate, and a fourth alignment film layer is disposed on a side of the fourth substrate close to the third substrate. The rubbing direction of the third alignment film layer is the same as the rubbing direction of the fourth alignment film layer.

11. An imaging system, characterized in that: The electronic filter comprises the electronic filter as described in any one of claims 1 to 10.

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