CN213690165U

CN213690165U - Silicon-based liquid crystal and optical wavelength selection switch

Info

Publication number: CN213690165U
Application number: CN202022366297.7U
Authority: CN
Inventors: 熊培成; 李爱源; 吴梓荣; 陈嵘; 洪俊斌
Original assignee: Shenzhen AV Display Co Ltd
Current assignee: Shenzhen AV Display Co Ltd
Priority date: 2020-10-21
Filing date: 2020-10-21
Publication date: 2021-07-13
Anticipated expiration: 2030-10-21

Abstract

The utility model provides a liquid crystal on silicon and optical wavelength selective switch, liquid crystal on silicon is including the conductive glass who arranges in proper order, first orientation layer, the liquid crystal layer, the second orientation layer, increase the reflection stratum, pixel electrode and substrate, communication light vertical incidence is silicon liquid crystal, through conductive glass, first orientation layer, the liquid crystal layer, the second orientation layer, reach the reflection stratum that increases on the reflection stratum, it includes two-layer or above dielectric film to increase the reflection stratum, the refracting index of adjacent dielectric film is different, can effectively improve liquid crystal on silicon's reflectivity through like this, its insertion loss has been reduced.

Description

Silicon-based liquid crystal and optical wavelength selection switch

Technical Field

The utility model belongs to the technical field of optical communication and specifically relates to indicate a silica-based liquid crystal and optical wavelength selective switch.

Background

Liquid Crystal On Silicon (LCOS) is a reflective Liquid Crystal device, and reflects or deflects light by using a mirror plated on a pixel electrode, and its application fields include AR/VR glasses, and a light Wavelength Selective Switch (WSS).

The existing silicon-based liquid crystal on the market generally has the problems of low reflection rate and large insertion loss.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a silicon-based liquid crystal and optical wavelength selective switch to increase silicon-based liquid crystal's reflectivity, reduce its insertion loss.

In order to solve the technical problem, the utility model discloses a following technical scheme:

in a first aspect, there is provided a liquid crystal on silicon comprising:

a substrate;

a pixel electrode formed on the substrate;

a reflective layer formed on the pixel electrode;

the reflection increasing layer is formed on the reflection layer and comprises two or more dielectric films, and the refractive indexes of the adjacent dielectric films are different;

a second alignment layer formed on the reflection increasing layer;

a liquid crystal layer formed on the second alignment layer;

a first alignment layer formed on the liquid crystal layer; and the number of the first and second groups,

and a conductive glass formed on the first alignment layer.

In a second aspect, there is provided an optical wavelength selective switch comprising liquid crystal on silicon as described above.

The beneficial effects of the utility model reside in that:

the utility model provides a liquid crystal on silicon, from top to bottom include conductive glass in proper order, first alignment layer, the liquid crystal layer, the second alignment layer, increase the reflection stratum, pixel electrode and substrate, communication light vertical incidence liquid crystal on silicon, through conductive glass, first alignment layer, the liquid crystal layer, the second alignment layer reaches the reflection stratum that increases on the reflection stratum, increase the reflection stratum and include two layers or more dielectric films, the refracting index of adjacent dielectric film is different, can effectively improve liquid crystal on silicon's reflectivity through this, reduced its insertion loss.

Drawings

The following detailed description of the specific structure of the present invention with reference to the accompanying drawings

Fig. 1 is a schematic structural diagram of a liquid crystal on silicon according to a first embodiment of the present invention.

Detailed Description

In order to explain technical contents, structural features, and objects and effects of the present invention in detail, the following description is given in conjunction with the embodiments and the accompanying drawings.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a liquid crystal on silicon according to a first embodiment of the present invention. As shown in fig. 1, a first aspect of the present invention provides a liquid crystal on silicon, including:

a substrate 10;

a pixel electrode 20 formed on the substrate 10;

a reflective layer 30 formed on the pixel electrode 20;

a reflection increasing layer 40 formed on the reflection layer 30, wherein the reflection increasing layer 40 includes two or more dielectric films, and refractive indexes of adjacent dielectric films are different;

a second alignment layer 50 formed on the reflection increasing layer 40;

a liquid crystal layer 60 formed on the second alignment layer 50;

a first alignment layer 70 formed on the liquid crystal layer 60; and the number of the first and second groups,

and a conductive glass 80 formed on the first alignment layer 70.

Specifically, the silicon-based liquid crystal adopts an ECB mode or one of a VA mode and a TN mode, the reflection increasing layer 40 is made of multiple dielectric films in a vacuum evaporation or magnetron sputtering or PECVD or photolithography manner, the optical path of each dielectric film is 1/4 of the target wavelength, the total number of layers is an even number, the preferable liquid crystal layer 60 adopts an ECB mode, the maximum phase control depth of the ECB mode is greater than 1.25 times of the target wavelength, so as to achieve the sufficient phase control depth of the communication band, the conductive glass 80 is borosilicate ITO conductive glass, and the thermal expansion coefficient of the conductive glass is 2.8 ppm/deg.c-6 ppm/deg.c.

The beneficial effects of the utility model reside in that:

Further, the material of each dielectric film layer at least comprises one of Si3N4, Si, Ta2O5, ZrO2, TiO2, SiO2 and MgF 2.

TABLE 1A structure and parameter example table of reflection increasing layer

Referring to table 1, optionally, the reflection increasing layer 40 is specifically formed by H/L units arranged periodically, where H represents a high refractive index dielectric film, ZrO2 is used as a material, and the optical path is λ/4, L represents a low refractive index dielectric film, SiO2 is used as a material, and the optical path is λ/4, and λ is the wavelength of incident light. Specifically, the total optical length of each H/L unit is lambda/2, the number of the H/L units is a natural number which is more than 1, the optical length nd of each dielectric film layer is equal to the thickness d multiplied by the refractive index n, and the optical length of each H/L unit is the sum of the optical lengths of all the dielectric films in the unit.

TABLE 2 Another Structure and parameter example Table of the reflection increasing layer

Referring to table 2, optionally, the reflection enhancing layer 40 is specifically formed by xH/L/yH units, where H represents a high refractive index dielectric film, the material is ZrO2, the optical path length is λ/4, L represents a low refractive index dielectric film, the material is SiO2, the optical path length is λ/4, λ is the wavelength of incident light, x + y is 1, x and y respectively represent the number of layers of the dielectric film, and 0< x <1, and 0< y < 1. In this embodiment, the H layers and the L layers are alternately arranged, and it is only necessary to ensure that the total number of the H layers at the head and the tail is added to be 1, and the H layer or the L layer in the middle is not divided.

TABLE 3 Another structure and parameter example table of reflection increasing layer

Referring to table 3, optionally, the reflection enhancing layer 40 is specifically formed by xL/H/yL units, where H represents a high refractive index dielectric film, the material is ZrO2, the optical path length is λ/4, L represents a low refractive index dielectric film, the material is SiO2, the optical path length is λ/4, λ is the wavelength of incident light, x + y is 1, x and y respectively represent the number of layers of the dielectric film, and 0< x <1, and 0< y < 1. In this embodiment, the H layers and the L layers are alternately arranged, and it is only necessary to ensure that the total number of the L layers at the head and the tail is added to be 1, and the H layer or the L layer in the middle is not divided.

Specifically, the material of the reflective layer 30 is one of Cu, Al, Au, and Ag, which can effectively improve the reflectivity.

Further, the liquid crystal on silicon further includes a conduction tube disposed between the pixel electrode 20 and the substrate 10 to conduct a circuit between the pixel electrode 20 and the driving unit in the substrate 10 through the insulating plate under the pixel electrode 20.

More specifically, the first alignment layer 70 and the second alignment layer 50 are polyimide, which functions to align liquid crystal molecules of the liquid crystal layer 60 in a certain direction.

Alternatively, the first alignment layer 70 and the second alignment layer 50 are obliquely evaporated oxides, such as SiO2, Si3N4, and the like, and are fabricated by an oblique evaporation process. Preferably, the SiO2 is adopted to perform an inclined evaporation process according to a certain angle, the inclined evaporation angle is within the range of 20-90 degrees, the optical temperature of the device adopting the evaporation process is better, the refractive index is between 1.1-1.5, and the improvement of the reflectivity of an interface is facilitated.

Further, the conductive glass 80 is provided with a conductive layer on one side thereof close to the liquid crystal layer 60, and is coated with an AR coating on the other side. The conductive layer is an ITO conductive layer that acts as a common electrode regulated by the liquid crystal layer 60, and the AR coating has the effect of increasing the transmittance. The pixel electrode 20 is connected to the source or drain of the substrate 10 through a conduction tube, and applies a voltage to the liquid crystal layer 60 together with the conductive layer, thereby realizing phase adjustment.

The utility model discloses the second aspect still provides an optical wavelength selective switch, include as above silicon-based liquid crystal, optical wavelength selective switch's beneficial effect lies in having improved the reflectivity to the communication light, has reduced insertion loss.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A liquid crystal on silicon, comprising:

a substrate;

a pixel electrode formed on the substrate;

a reflective layer formed on the pixel electrode;

a second alignment layer formed on the reflection increasing layer;

a liquid crystal layer formed on the second alignment layer;

and a conductive glass formed on the first alignment layer.

2. The LCOS according to claim 1, wherein each of said dielectric films comprises at least one of Si3N4, Si, Ta2O5, ZrO2, TiO2, SiO2, MgF 2.

3. The LCOS according to claim 1, wherein said reflection increasing layer is formed of H/L cells periodically arranged, wherein H represents a high refractive index dielectric film, an optical length is λ/4, L represents a low refractive index dielectric film, an optical length is λ/4, and λ is an incident light wavelength.

4. The lcos of claim 1, wherein the reflection enhancing layer is specifically composed of xH/L/yH units, wherein H represents a high refractive index dielectric film, an optical length is λ/4, L represents a low refractive index dielectric film, an optical length is λ/4, λ is an incident light wavelength, x + y is 1, x and y represent the number of layers of the dielectric film, and 0< x <1, and 0< y <1, respectively.

5. The lcos of claim 1, wherein the reflection enhancing layer is specifically composed of xL/H/yL units, wherein H represents a high refractive index dielectric film, an optical length is λ/4, L represents a low refractive index dielectric film, an optical length is λ/4, λ is an incident light wavelength, x + y is 1, x and y represent the number of layers of the dielectric film, and 0< x <1, and 0< y <1, respectively.

6. The LCOS according to claim 1, wherein the material of said reflective layer is one of Cu, Al, Au and Ag.

7. The liquid crystal on silicon of claim 1, further comprising a conducting tube disposed between the pixel electrode and the substrate.

8. The liquid crystal on silicon of claim 1, wherein the first and second alignment layers are polyimide or SiO2 or Si3N 4.

9. The liquid crystal on silicon of claim 1, wherein the conductive glass is provided with a conductive layer on one side thereof adjacent to the liquid crystal layer and is AR coated on the other side thereof.

10. An optical wavelength selective switch comprising the liquid crystal on silicon according to any one of claims 1 to 9.