A method and structure for inhibiting energy loss

Abstract

The present application relates to a kind of method and structure for inhibiting energy loss, solve the current liquid crystal wave sheet energy transmittance is not low problem.Structure includes: liquid crystal layer;With the first orientation film and the second orientation film respectively contacted with the two sides of liquid crystal layer, for orientation liquid crystal layer;First substrate and second substrate;Air-substrate interface refractive index matching film is respectively plated in the outer side of two substrates, for reducing the Fresnel reflection energy loss of air and first substrate, air and second substrate interface;Conductive film is respectively plated in the inner side of two substrates, for driving liquid crystal layer;First conductive film-liquid crystal refractive index matching film and second conductive film-liquid crystal refractive index matching film are respectively plated on two conductive films, for reducing the energy loss caused by interface between conductive film and liquid crystal layer.The structure can significantly improve the energy utilization efficiency of liquid crystal wave sheet, meet the needs of high efficiency, large angle, non-continuity light beam deflection based on liquid crystal wave sheet and liquid crystal polarization grating.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of non-mechanical beam deflection, and particularly relates to a method and structure for suppressing energy loss. BACKGROUND

[0002] As a core component in the fields of photoelectric information such as laser radar, laser communication and laser active imaging, the performance of a beam deflection module directly determines the overall efficiency of the system. As a new type of geometric phase optical element, a liquid crystal polarization grating brings a revolutionary breakthrough to the beam deflection technology with its unique advantages of large aperture, high efficiency and wide angle. The new beam deflection technology based on the liquid crystal polarization grating can not only meet the two key performance indicators of large aperture and wide angle, but also significantly improve the overall performance of the system, which shows a broad application prospect in the fields of satellite laser communication, airborne laser radar, mid-wave infrared staring imaging, ToF camera, laser countermeasure and laser guidance.

[0003] At present, the beam deflection technology based on the liquid crystal polarization grating mainly adopts a cascade structure, that is, a large-angle and non-continuous beam deflection is realized by combining multiple liquid crystal wave plates and liquid crystal polarization gratings. Although this structure has the advantages of simple control strategy, high reliability, easy realization of miniaturization, flexible control and low power consumption, it also has obvious limitations. Since the energy utilization efficiency of each liquid crystal wave plate in the cascade structure will have a cumulative effect on the overall performance, the energy loss problem of a single liquid crystal wave plate becomes a bottleneck restricting the engineering application of the liquid crystal polarization grating technology.

[0004] The energy utilization efficiency of a liquid crystal wave plate is mainly determined by two key factors: energy transmittance and light regulation efficiency. Among them, the energy transmittance is significantly affected by the interface refractive index matching degree of the liquid crystal wave plate and the Fabry-Perot effect of the liquid crystal layer. Moreover, with the increase of the liquid crystal birefringence difference (Δn = n e -n o ), the refractive index of the conductive film will be more difficult to match n e and n o at the same time, which will make the Fabry-Perot effect in the liquid crystal layer more significant, resulting in more serious energy loss. SUMMARY

[0005] In order to solve the problems of serious energy loss and low energy transmittance of the liquid crystal wave plate caused by the mismatch of refractive index of multiple interfaces, the application provides a method and structure for inhibiting energy loss, optimizes the design of each film layer system of the liquid crystal wave plate, maximally eliminates the interface energy loss, effectively inhibits the Fabry-Perot effect in the liquid crystal layer, and realizes the liquid crystal wave plate with high energy transmittance. The application can significantly improve the overall energy utilization efficiency of the cascade structure, and lays a solid foundation for the engineering application of the liquid crystal polarization grating technology.

[0006] In order to solve the above problems, the application adopts the following technical scheme:

[0007] A method for inhibiting energy loss, comprising the following steps:

[0008] Step 1: plating a first air-substrate interface refractive index matching film and a second air-substrate interface refractive index matching film on the outer sides of a first substrate and a second substrate for supporting a liquid crystal layer, respectively, the first air-substrate interface refractive index matching film is used to reduce the Fresnel reflection energy loss of the interface between air and the first substrate, and the second air-substrate interface refractive index matching film is used to reduce the Fresnel reflection energy loss of the interface between air and the second substrate;

[0009] Step 2: plating a first conductive film and a second conductive film on the inner sides of the first substrate and the second substrate, respectively, the first conductive film and the second conductive film are used to drive the liquid crystal layer;

[0010] Step 3: plating a first conductive film-liquid crystal refractive index matching film and a second conductive film-liquid crystal refractive index matching film on the first conductive film and the second conductive film, respectively, the first conductive film-liquid crystal refractive index matching film is used to reduce the energy loss caused by the interface between the first conductive film and the liquid crystal layer, and the second conductive film-liquid crystal refractive index matching film is used to reduce the energy loss caused by the interface between the second conductive film and the liquid crystal layer;

[0011] Step 4: spin coating a first alignment film and a second alignment film on the first conductive film-liquid crystal refractive index matching film and the second conductive film-liquid crystal refractive index matching film, respectively, the first alignment film and the second alignment film are used to align the liquid crystal layer;

[0012] Step 5: pouring liquid crystal material between the first alignment film and the second alignment film to form a liquid crystal layer.

[0013] Meanwhile, the application also provides a structure for inhibiting energy loss, comprising:

[0014] a liquid crystal layer;

[0015] a first alignment film and a second alignment film in contact with the two sides of the liquid crystal layer, respectively, for aligning the liquid crystal layer;

[0016] a first substrate and a second substrate for supporting a first alignment film, a second alignment film and a liquid crystal layer;

[0017] a first air-substrate interface refractive index matching film plated on the outside of the first substrate for reducing Fresnel reflection energy loss at the air and the first substrate interface;

[0018] a second air-substrate interface refractive index matching film plated on the outside of the second substrate for reducing Fresnel reflection energy loss at the air and the second substrate interface;

[0019] a first conductive film and a second conductive film plated on the inside of the first substrate and the second substrate respectively for driving the liquid crystal layer;

[0020] a first conductive film-liquid crystal refractive index matching film plated on the first conductive film and in contact with the first alignment film for reducing energy loss caused by the interface between the first conductive film and the liquid crystal layer;

[0021] a second conductive film-liquid crystal refractive index matching film plated on the second conductive film and in contact with the second alignment film for reducing energy loss caused by the interface between the second conductive film and the liquid crystal layer.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] The present application provides a method and a structure for suppressing energy loss, which are different from the conventional method and structure for suppressing energy loss of liquid crystal wave plate. The refractive index matching film is plated between the conductive film and the liquid crystal layer, and the air-substrate interface refractive index matching film is plated, which can fundamentally eliminate the Fresnel reflection loss caused by the refractive index mismatch of multiple interfaces, greatly suppress the Fabry-Perot effect in the liquid crystal layer, and realize the suppression of energy loss of liquid crystal wave plate. Through the implementation of the present application, the energy utilization efficiency of liquid crystal wave plate can be significantly improved, and the needs of high efficiency, large angle and non-continuous beam deflection based on liquid crystal wave plate and liquid crystal polarization grating can be met. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 a schematic diagram of a structure for suppressing energy loss according to one embodiment of the present application;

[0025] Figure 2 a flow chart of a method for suppressing energy loss according to another embodiment of the present application;

[0026] Explanation of reference numerals: 1, first air-substrate interface refractive index matching film; 2, first substrate; 3, first conductive film; 4, first conductive film-liquid crystal refractive index matching film; 5, first orientation film; 6, liquid crystal layer; 7, second orientation film; 8, second conductive film-liquid crystal refractive index matching film; 9, second conductive film; 10, second substrate; 11, second air-substrate interface refractive index matching film. DETAILED DESCRIPTION

[0027] In order to make the technical personnel in the art better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings.

[0028] Reference Figure 1 The embodiment provides a structure for inhibiting energy loss, which specifically comprises a first air-substrate interface refractive index matching film 1, a first substrate 2, a first conductive film 3, a first conductive film-liquid crystal refractive index matching film 4, a first orientation film 5, a liquid crystal layer 6, a second orientation film 7, a second conductive film-liquid crystal refractive index matching film 8, a second conductive film 9, a second substrate 10, and a second air-substrate interface refractive index matching film 11.

[0029] The first orientation film 5 and the second orientation film 7 respectively contact two sides of the liquid crystal layer 6, and are used for orienting the liquid crystal layer 6.

[0030] The first substrate 2 and the second substrate 10 are used for supporting the liquid crystal layer 6 and the first orientation film 5 and the second orientation film 7.

[0031] The first air-substrate interface refractive index matching film 1 and the second air-substrate interface refractive index matching film 11 are respectively plated on the outer side of the first substrate 2 and the second substrate 10, and according to the Fresnel formula, the first air-substrate interface refractive index matching film 1 can significantly reduce the Fresnel reflection energy loss of the air and the first substrate 2 interface, and the second air-substrate interface refractive index matching film 11 can significantly reduce the Fresnel reflection energy loss of the air and the second substrate 10 interface.

[0032] The first conductive film 3 and the second conductive film 9 are respectively plated on the inner side of the first substrate 2 and the second substrate 10, that is, the back surface opposite to the first air-substrate interface refractive index matching film 1 and the second air-substrate interface refractive index matching film 11, and the first conductive film 3 and the second conductive film 9 are used for driving the liquid crystal layer 6 under the action of an applied voltage V.

[0033] The first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 are respectively plated on the first conductive film 3 and the second conductive film 9, and the first conductive film 3 is in contact with the first orientation film 5, and the second conductive film 9 is in contact with the second orientation film 7. According to the Fresnel formula, the first conductive film-liquid crystal refractive index matching film 4 can significantly reduce the energy loss caused by the interface between the first conductive film 3 and the liquid crystal layer 6, and the second conductive film-liquid crystal refractive index matching film 8 can significantly reduce the energy loss caused by the interface between the second conductive film 9 and the liquid crystal layer 6. In this embodiment, by plating a refractive index matching film between the conductive film and the liquid crystal layer, the Fresnel reflection energy loss caused by the refractive index mismatch of the interface can be significantly reduced, and the Fabry-Perot effect in the liquid crystal layer can also be reduced, thereby finally reducing the energy loss of the conductive film-liquid crystal interface.

[0034] Further, the liquid crystal layer 6 in this embodiment is regularly oriented under the action of the first orientation film 5 and the second 7, forming a mode including but not limited to anti-parallel orientation, parallel orientation, vertical orientation, and the effective refractive index of the liquid crystal layer 6 changes under the control of voltage. The effective refractive index of the liquid crystal layer 6 is:

[0035]

[0036] Wherein, n eff is the effective refractive index of the liquid crystal layer 6 under a certain voltage V, n e and n o are the extraordinary light refractive index and ordinary light refractive index of the liquid crystal molecule respectively, and θ is the tilt angle of the liquid crystal molecule in the vertical substrate direction.

[0037] Further, the film layer structure of the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 in this embodiment is first designed according to the average refractive index of the conductive film and the liquid crystal layer 6, and a conventional film layer design method is used, then the designed film layer structure and the liquid crystal layer are constructed together to build a light diffraction model, and the energy transmittance is used as the evaluation standard to evaluate the above-mentioned film layer structure, and the design of the above-mentioned film layer structure is realized through repeated iteration, wherein the average refractive index of the liquid crystal layer 6 is:

[0038]

[0039] Wherein, is the average refractive index of the liquid crystal layer 6, n e and n o are the extraordinary light refractive index and ordinary light refractive index of the liquid crystal molecule respectively.

[0040] The first air-substrate interface refractive index matching film 1, the second air-substrate interface refractive index matching film 11, the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 in the embodiment depend on the wavelength and angle of the incident light, i.e. the wavelength or angle of the incident light is different, the number of layers, refractive index distribution, thickness and other parameters of the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 are different, the corresponding plating processes are different, and the specific corresponding relationship needs to be accurately designed according to the film structure.

[0041] The embodiment also provides a specific example of a structure for inhibiting energy loss of a liquid crystal wave plate, and energy efficiency comparison experiments are performed.

[0042] In this example, the first substrate 2 and the second substrate 10 complete plating of the first air-substrate interface refractive index matching film 1 and the second air-substrate interface refractive index matching film 11, and the working wavelength of the liquid crystal wave plate is 1550 nm, n e = 1.86, n o = 1.52, Δn = n e -n o = 0.34, the thickness of the liquid crystal layer 6 is 5.0 μm, the liquid crystal layer 6 is in a homeotropic alignment mode, and linearly polarized light is vertically incident and emitted.

[0043] When the direction of the incident linearly polarized light is 0° with respect to the long axis direction (n e ) of the liquid crystal molecules, the energy transmittance of the liquid crystal wave plate is 91.7% measured by a power meter;

[0044] When the direction of the incident linearly polarized light is 45° with respect to the long axis direction (n e ) of the liquid crystal molecules, the energy transmittance of the liquid crystal wave plate is 94.7% measured by a power meter;

[0045] When the direction of the incident linearly polarized light is 90° with respect to the long axis direction (n e ) of the liquid crystal molecules (n o ), the energy transmittance of the liquid crystal wave plate is 97.1% measured by a power meter.

[0046] After the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 are designed and plated according to the above-mentioned parameters of the conductive film, liquid crystal refractive index and liquid crystal thickness, the energy transmittance of the liquid crystal wave plate is retested, and when the direction of the incident linearly polarized light is 0° with respect to the long axis direction (n e) respectively, and the energy transmittance of the liquid crystal wave plate is 95.5%, 96.8%, and 97.2% respectively. Compared with before plating the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8, the energy transmittance is increased by 3.8%, 2.1%, and 0.1% respectively.

[0047] As can be seen from the above examples, the structure for inhibiting energy loss proposed by the present application significantly improves the energy transmittance of the liquid crystal wave plate, and will play an important role when used in a cascade structure.

[0048] Referring to Figure 2 In another embodiment, a method for inhibiting energy loss is provided, which mainly comprises the following steps:

[0049] Step 1: Plating a first air-substrate interface refractive index matching film 1 and a second air-substrate interface refractive index matching film 11 on the outer side of a first substrate 2 and a second substrate 10 respectively for supporting a liquid crystal layer 6, wherein the first air-substrate interface refractive index matching film 1 is used to reduce the Fresnel reflection energy loss at the interface between air and the first substrate 2, and the second air-substrate interface refractive index matching film 11 is used to reduce the Fresnel reflection energy loss at the interface between air and the second substrate 10.

[0050] Step 2: Plating a first conductive film 3 and a second conductive film 9 on the outer side of the first substrate 2 and the second substrate 10 respectively, which are used to drive the liquid crystal layer 6 under the action of an applied voltage V.

[0051] Step 3: Plating a first conductive film-liquid crystal refractive index matching film 4 and a second conductive film-liquid crystal refractive index matching film 8 on the first conductive film 3 and the second conductive film 9 respectively, wherein the first conductive film-liquid crystal refractive index matching film 4 is used to reduce the energy loss caused by the interface between the first conductive film 3 and the liquid crystal layer 6, and the second conductive film-liquid crystal refractive index matching film 8 is used to reduce the energy loss caused by the interface between the second conductive film 9 and the liquid crystal layer 6.

[0052] Step 4: Spin coating a first alignment film 5 and a second alignment film 7 on the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 respectively, wherein the first alignment film 5 and the second alignment film 7 are used to align the liquid crystal layer 6.

[0053] Step 5: After alignment, press into a box, then inject liquid crystal material between the first alignment film 5 and the second alignment film 7 to form a liquid crystal layer (6), and finally obtain a liquid crystal wave plate capable of inhibiting energy loss.

[0054] Further, the liquid crystal layer 6 in the embodiment is regularly oriented under the action of the first orientation film 5 and the second orientation film 7, and forms a mode including but not limited to an anti-parallel orientation mode, a parallel orientation mode, and a vertical orientation mode, and the effective refractive index of the liquid crystal layer 6 changes under the control of voltage, and the effective refractive index of the liquid crystal layer 6 is:

[0055]

[0056] wherein n eff is the effective refractive index of the liquid crystal layer 6 under a certain voltage V, n e and n o are the extraordinary light refractive index and the ordinary light refractive index of the liquid crystal molecules respectively, and θ is the tilt angle of the liquid crystal molecules in the vertical substrate direction.

[0057] Further, the film layer structure of the first conductive film-liquid crystal refractive index matching film 4 and the second conductive film-liquid crystal refractive index matching film 8 in the embodiment is first designed according to the average refractive index of the conductive film and the liquid crystal layer 6, a conventional film layer design method is adopted, then the designed film layer structure and the liquid crystal layer are constructed together to form a light diffraction model, and the above film layer structure is evaluated according to the energy transmittance as the evaluation standard, and the design of the above film layer structure is realized through repeated iteration, wherein the average refractive index of the liquid crystal layer 6 is:

[0058]

[0059] wherein, is the average refractive index of the liquid crystal layer 6, n e and n o are the extraordinary light refractive index and the ordinary light refractive index of the liquid crystal molecules respectively.

[0060] The method and structure for suppressing energy loss of the liquid crystal wave plate proposed in the application are different from the traditional method and structure for suppressing energy loss of the liquid crystal wave plate, and the refractive index matching film is plated between the conductive film and the liquid crystal layer, and the plating of the air-substrate interface refractive index matching film is combined, so that the Fresnel reflection loss caused by the mismatch of the refractive index of multiple interfaces can be fundamentally eliminated, the Fabry-Perot effect in the liquid crystal layer can be greatly suppressed, and the energy loss of the liquid crystal wave plate can be suppressed. Through the implementation of the application, the energy utilization efficiency of the liquid crystal wave plate can be significantly improved, and the needs of high efficiency, large angle, and non-continuous beam deflection based on the liquid crystal wave plate and the liquid crystal polarization grating can be met.

[0061] The above only describes the preferred embodiments of the application, and is not used to limit the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for suppressing energy loss, characterized in that: The following steps are involved: Step 1: A first air-substrate interface refractive index matching film (1) and a second air-substrate interface refractive index matching film (11) are respectively plated on the outer sides of a first substrate (2) and a second substrate (10) for supporting a liquid crystal layer (6), wherein the first air-substrate interface refractive index matching film (1) is used to reduce Fresnel reflection energy loss at the interface between air and the first substrate (2), and the second air-substrate interface refractive index matching film (11) is used to reduce Fresnel reflection energy loss at the interface between air and the second substrate (10); Step 2: coating the first conductive film (3) and the second conductive film (9) on the inner sides of the first substrate (2) and the second substrate (10), respectively, wherein the first conductive film (3) and the second conductive film (9) are used to drive the liquid crystal layer (6); Step 3: a first conductive film-liquid crystal refractive index matching film (4) and a second conductive film-liquid crystal refractive index matching film (8) are respectively plated on the first conductive film (3) and the second conductive film (9), wherein the first conductive film-liquid crystal refractive index matching film (4) is used to reduce energy loss caused by the interface between the first conductive film (3) and the liquid crystal layer (6), and the second conductive film-liquid crystal refractive index matching film (8) is used to reduce energy loss caused by the interface between the second conductive film (9) and the liquid crystal layer (6); Step 4: forming a first orientation film (5) and a second orientation film (7) by spin coating on the first conductive film-liquid crystal refractive index matching film (4) and the second conductive film-liquid crystal refractive index matching film (8), respectively, wherein the first orientation film (5) and the second orientation film (7) are used to align the liquid crystal layer (6); Step 5: pouring liquid crystal material between the first alignment film (5) and the second alignment film (7) to form a liquid crystal layer (6).

2. The method for suppressing energy loss according to claim 1, wherein: The liquid crystal layer (6) is regularly oriented under the action of the first orientation film (5) and the second orientation film (7), forming any one of an antiparallel orientation mode, a parallel orientation mode, and a vertical orientation mode, and the effective refractive index of the liquid crystal layer (6) is: Among them, n eff is the effective refractive index of the liquid crystal layer (6) at voltage V, n e and n o are the extraordinary refractive index and ordinary refractive index of the liquid crystal molecules, respectively, and θ is the tilt angle of the liquid crystal molecules in the direction perpendicular to the substrate.

3. A method for suppressing energy loss according to claim 1 or 2, characterized in that: The average refractive index of the liquid crystal layer (6) is: n=(n e +n o ) / 2 Wherein, n is the average refractive index of the liquid crystal layer (6), n e and n o are the extraordinary refractive index and ordinary refractive index of the liquid crystal molecules respectively.

4. A structure for suppressing energy loss, characterized in that: include: a liquid crystal layer (6); a first orientation film (5) and a second orientation film (7) respectively contacting both sides of the liquid crystal layer (6), and used for orienting the liquid crystal layer (6); A first substrate (2) and a second substrate (10) for supporting the first alignment film (5), the second alignment film (7) and the liquid crystal layer (6); A first air-substrate interface refractive index matching film (1) plated on the outside of the first substrate (2) is used to reduce Fresnel reflection energy loss at the interface between air and the first substrate (2); A second air-substrate interface refractive index matching film (11) plated on the outside of the second substrate (10) is used to reduce Fresnel reflection energy loss at the interface between air and the second substrate (10); A first conductive film (3) and a second conductive film (9) respectively plated on the inner sides of the first substrate (2) and the second substrate (10), and used for driving the liquid crystal layer (6); A first conductive film-liquid crystal refractive index matching film (4) plated on the first conductive film (3) and in contact with the first orientation film (5) is used to reduce energy loss caused by the interface between the first conductive film (3) and the liquid crystal layer (6); A second conductive film-liquid crystal refractive index matching film (8) plated on the second conductive film (9) and in contact with the second orientation film (7) is used to reduce energy loss caused by the interface between the second conductive film (9) and the liquid crystal layer (6).

5. The structure for suppressing energy loss according to claim 4, characterized in that: The liquid crystal layer (6) is regularly oriented under the action of the first orientation film (5) and the second orientation film (7), forming any one of an antiparallel orientation mode, a parallel orientation mode, and a vertical orientation mode, and the effective refractive index of the liquid crystal layer (6) is: Among them, n eff is the effective refractive index of the liquid crystal layer (6) at voltage V, n e and n o are the extraordinary refractive index and ordinary refractive index of the liquid crystal molecules, respectively, and θ is the tilt angle of the liquid crystal molecules in the direction perpendicular to the substrate.

6. The structure for suppressing energy loss according to claim 4 or 5, characterized in that: The average refractive index of the liquid crystal layer (6) is: in, is the average refractive index of the liquid crystal layer (6), n e and n o are the extraordinary refractive index and ordinary refractive index of the liquid crystal molecules respectively.

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