WO2021238751A1

WO2021238751A1 - Liquid crystal on silicon device

Info

Publication number: WO2021238751A1
Application number: PCT/CN2021/094760
Authority: WO
Inventors: 贾伟; 李彤
Original assignee: 华为技术有限公司
Priority date: 2020-05-25
Filing date: 2021-05-20
Publication date: 2021-12-02
Also published as: CN113721392B; CN113721392A

Abstract

Disclosed in embodiments of the present application is a liquid crystal on silicon (LCOS) device, used for flexibly adjusting the lateral electric field between two pixels to flexibly handle the fringe field effect, thereby improving the performance of LCOS chips. The embodiments of the present application comprise: a first electrode layer, a second electrode layer, and a liquid crystal layer located between M first electrodes and N second electrodes; the first electrode layer comprises M first electrodes, and the second electrode layer comprises N second electrodes, wherein both M and N are positive integers greater than one; the M first electrodes, the N second electrodes, and the liquid crystal layer therebetween constituting K pixels, wherein one pixel corresponds to one first electrode and one second electrode, and K is a positive integer greater than one; and for any one of the K pixels, the voltage of the corresponding first electrode being greater than the voltage of the corresponding second electrode.

Description

Silicon-based liquid crystal device

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of China, the application number is 202010448560.9, and the application name is "a silicon-based liquid crystal device" on May 25, 2020, the entire content of which is incorporated into this application by reference middle.

Technical field

The embodiments of the present application relate to the field of communication technology, and in particular to a liquid crystal on silicon device.

Background technique

Optical communication (Optical Communication) is a communication method that uses light as the carrier wave. As an important communication device in optical communications, the Reconfigurable Optical Add-Drop Multiplexer (ROADM) is used to upload or download light of a specific wavelength. The main device that realizes this function is a wavelength selective switch. (Wavelength Selective Switch, WSS).

The wavelength selective switch includes a Liquid Crystal on Silicon (LCOS) chip, and the LCOS chip is used to modulate the phase of incident light so that the light is diffracted. Specifically, the LCOS chip includes two electrode layers and a liquid crystal layer located between the two electrode layers. One electrode layer is a common electrode, and the other electrode layer includes a plurality of pixel electrodes. The liquid crystal molecules in the liquid crystal layer can modulate the phase of incident light so that the light is diffracted. The voltage difference between the pixel electrode and the common electrode can change the offset angle of the liquid crystal molecules in the liquid crystal layer, and the change of the offset angle will change the refractive index of the liquid crystal molecules, thereby changing the degree of phase modulation of incident light.

Among them, the pixel electrode, the common electrode, and the liquid crystal layer between the two constitute a pixel, and the voltage difference between the pixel electrode and the common electrode may also be called the voltage difference of the pixel. If the voltage difference between two adjacent pixels is different, a lateral electric field will be formed between the two pixels, and the lateral electric field will also affect the offset angle of the liquid crystal molecules, thereby affecting the degree of phase modulation of light. This phenomenon is also called fringe field effect. The fringe field effect can affect the performance of the LCOS chip, which in turn affects the performance of the wavelength selection module. For example, the fringe field effect can cause the wavelength selection module to generate crosstalk.

Therefore, it is necessary to deal with the fringe field effect to improve the performance of the LCOS chip.

Summary of the invention

The embodiment of the present application provides a liquid crystal on silicon device that can flexibly adjust the lateral electric field between two pixels to flexibly handle fringe field effects, thereby improving the performance of the LCOS chip.

The first aspect of the embodiments of the present application provides a liquid crystal on silicon device, including: a first electrode layer, a liquid crystal layer, and a second electrode layer.

The first electrode layer and the second electrode layer may be arranged in parallel, and the liquid crystal layer is located between the first electrode layer and the second electrode layer.

The first electrode layer includes M first electrodes, and the second electrode layer includes N second electrodes, where both M and N are positive integers greater than one.

M first electrodes, N second electrodes, and the liquid crystal layer between M first electrodes and N second electrodes constitute K pixels, where each pixel corresponds to a first electrode and a second electrode, K Is a positive integer greater than 1.

The voltage of the first electrode corresponding to any one of the K pixels is greater than the voltage of the corresponding second electrode.

Since the voltage of the first electrode corresponding to any one of the K pixels is greater than the voltage of the corresponding second electrode, for any two adjacent pixels, it is possible to adjust the first electrode of the two pixels. The voltage difference between the two adjacent pixels can be used to adjust the lateral electric field between the two adjacent pixels. The lateral electric field between the two adjacent pixels can also be adjusted by adjusting the voltage difference between the second electrodes in the two pixels. Electric field; therefore, the embodiment of the present application can flexibly adjust the lateral electric field between two pixels to flexibly handle fringe field effects, thereby improving the performance of the LCOS chip.

Based on the first aspect, the embodiments of the present application provide the first implementation manner of the first aspect, and there are two adjacent first electrodes with unequal voltages among the M first electrodes;

There are two adjacent second electrodes with unequal voltages among the N second electrodes.

Among them, the pixels to which two adjacent first electrodes belong can be the same as the pixels to which two adjacent second electrodes belong, and the pixels to which two adjacent first electrodes belong can also be connected to two adjacent second electrodes. The pixel to which it belongs is different.

In this embodiment, in the first electrode layer, the voltage difference of at least two adjacent first electrodes is controlled not to be zero, and in the second electrode layer, the voltage difference of at least two adjacent second electrodes is controlled The voltage difference is not zero, so that the lateral electric field in the liquid crystal on silicon device can be adjusted.

Based on the first implementation manner of the first aspect, the embodiments of the present application provide the second implementation manner of the first aspect. The K pixels include adjacent first pixels and second pixels, and the first pixels and second pixels can be It is used to modulate the phase of light of the same wavelength, and can also be used to modulate the phase of light of different wavelengths.

The first electrode corresponding to the first pixel is adjacent to the first electrode corresponding to the second pixel and the voltages are not equal;

The second electrode corresponding to the first pixel is adjacent to the second electrode corresponding to the second pixel and the voltages are not equal.

In this embodiment, for the adjacent first pixel and second pixel, the voltages of the first electrodes in the two pixels are controlled to be unequal, and the voltages of the second electrodes in the two pixels are controlled to be unequal, so as to realize the alignment. The lateral electric field between the first pixel and the second pixel is adjusted.

Based on the second implementation manner of the first aspect, an embodiment of the present application provides a third implementation manner of the first aspect. The first pixel and the second pixel are used to modulate the phase of light of the same wavelength.

Among them, the first pixel may correspond to the same grating period, or may belong to different grating periods.

In this embodiment, by controlling the voltages of the first electrodes in the two pixels to be unequal, and at the same time controlling the voltages of the second electrodes in the two pixels to be unequal, the two pixels that modulate the same wavelength of light The adjustment of the lateral electric field.

Based on the third implementation manner of the first aspect, an embodiment of the present application provides the fourth implementation manner of the first aspect, and the first pixel and the second pixel correspond to the same grating period.

In this embodiment, the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is controlled, and the second electrode corresponding to the first pixel and the second electrode corresponding to the second pixel are controlled. The voltage difference between can adjust the lateral electric field in one grating period.

Based on the third implementation manner of the first aspect, an embodiment of the present application provides the fifth implementation manner of the first aspect, and the first pixel and the second pixel correspond to different grating periods.

In this embodiment, the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is controlled, and the second electrode corresponding to the first pixel and the second electrode corresponding to the second pixel are controlled. The voltage difference between can adjust the transverse electric field at the junction of two adjacent grating periods.

Based on the second implementation manner of the first aspect, or the third implementation manner of the first aspect, or the fourth implementation manner of the first aspect, or the fifth implementation manner of the first aspect, the examples of this application provide In a sixth implementation manner of the first aspect, the voltage of the first electrode corresponding to the first pixel is greater than the voltage of the first electrode corresponding to the second pixel;

The voltage of the second electrode corresponding to the first pixel is smaller than the voltage of the second electrode corresponding to the second pixel.

In this embodiment, the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is positive, and the second electrode corresponding to the first pixel is different from the second electrode corresponding to the second pixel. The voltage difference between is negative, so it can play the role of weakening the transverse electric field, which is suitable for scenes where the transverse electric field is not conducive to phase modulation.

Based on the fifth implementation manner of the first aspect, the embodiments of the present application provide the seventh implementation manner of the first aspect. The voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is equal to , The voltage difference between the second electrode corresponding to the second pixel and the second electrode corresponding to the first pixel.

In this embodiment, since the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is equal to that between the second electrode corresponding to the second pixel and the second electrode corresponding to the first pixel Therefore, the transverse electric field can be further weakened to further reduce the influence of the transverse electric field on the phase modulation.

Based on the second implementation manner of the first aspect, or the third implementation manner of the first aspect, or the fourth implementation manner of the first aspect, or the fifth implementation manner of the first aspect, the examples of this application provide In an eighth implementation manner of the first aspect, the voltage of the first electrode corresponding to the first pixel is less than the voltage of the first electrode corresponding to the second pixel;

In this embodiment, the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is negative, and the second electrode corresponding to the first pixel is different from the second electrode corresponding to the second pixel. The voltage difference between the two is also negative, so it can strengthen the lateral electric field, which is suitable for scenarios where the lateral electric field is beneficial to phase modulation.

Based on the eighth implementation manner of the first aspect, an embodiment of the present application provides a ninth implementation manner of the first aspect. The voltage difference between the first electrode corresponding to the second pixel and the first electrode corresponding to the first pixel is greater than First preset value

The voltage difference between the second electrode corresponding to the second pixel and the second electrode corresponding to the first pixel is greater than the second preset value.

When the voltage difference between the first electrode corresponding to the second pixel and the first electrode corresponding to the first pixel is greater than the first preset value, and between the second electrode corresponding to the second pixel and the second electrode corresponding to the first pixel When the voltage difference is greater than the second preset value, it can ensure that the lateral electric field is relatively strong.

Based on the first aspect, or the first implementation of the first aspect, or the second implementation of the first aspect, or the third implementation of the first aspect, or the fourth implementation of the first aspect, or The fifth embodiment of the first aspect, or the sixth embodiment of the first aspect, or the seventh embodiment of the first aspect, or the eighth embodiment of the first aspect, or the ninth aspect of the first aspect The embodiments of the present application provide a tenth embodiment of the first aspect. The first electrode layer is a light-transmitting electrode layer, and the second electrode layer is a light-transmitting electrode layer.

In this embodiment, light can enter the liquid crystal layer from the first electrode layer, and finally exit from the second electrode layer through the liquid crystal layer.

Based on the first aspect, or the first implementation of the first aspect, or the second implementation of the first aspect, or the third implementation of the first aspect, or the fourth implementation of the first aspect, or The fifth embodiment of the first aspect, or the sixth embodiment of the first aspect, or the seventh embodiment of the first aspect, or the eighth embodiment of the first aspect, or the ninth aspect of the first aspect The embodiments of the present application provide an eleventh embodiment of the first aspect, the first electrode layer is a light-transmitting electrode layer, and the second electrode layer is a reflective electrode layer; or

The first electrode layer is a reflective electrode layer, and the second electrode layer is a light-transmitting electrode layer.

In this embodiment, light can enter the liquid crystal layer from the first electrode layer, after passing through the liquid crystal layer, be reflected at the second electrode layer, then pass through the liquid crystal layer again, and finally exit from the first electrode layer; or light can be emitted from the first electrode layer. The two electrode layers are injected into the liquid crystal layer, and after passing through the liquid crystal layer, reflection occurs on the first electrode layer, then passes through the liquid crystal layer again, and finally exits from the second electrode layer.

Based on the first aspect, or the first implementation of the first aspect, or the second implementation of the first aspect, or the third implementation of the first aspect, or the fourth implementation of the first aspect, or The fifth embodiment of the first aspect, or the sixth embodiment of the first aspect, or the seventh embodiment of the first aspect, or the eighth embodiment of the first aspect, or the ninth aspect of the first aspect The embodiments of the present application provide a twelfth embodiment of the first aspect. The first electrode layer is a reflective electrode layer, and the second electrode layer is a reflective electrode layer.

In this embodiment, light can enter the liquid crystal layer from one side of the liquid crystal layer, and then reflect on the first electrode layer for the first time. After passing through the liquid crystal layer again, light can be reflected on the second electrode layer for a second time, and finally passes through the liquid crystal layer. Layer and shoot out from the other side of the liquid crystal layer.

It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

In the liquid crystal on silicon device, the liquid crystal layer is located between the first electrode layer and the second electrode layer; the first electrode layer includes M first electrodes, and the second electrode layer includes N second electrodes, where both M and N are Is a positive integer greater than 1; M first electrodes, N second electrodes, and the liquid crystal layer between M first electrodes and N second electrodes constitute K pixels, where one pixel corresponds to one first electrode and For a second electrode, K is a positive integer greater than 1; the voltage of the first electrode corresponding to any one of the K pixels is greater than the voltage of the corresponding second electrode; based on the above-mentioned liquid crystal on silicon device, for any two phases Adjacent pixels can be adjusted by adjusting the voltage difference between the first electrodes in the two pixels to adjust the lateral electric field between the two adjacent pixels, or by adjusting the voltage difference between the second electrodes in the two pixels. To adjust the lateral electric field between the two adjacent pixels;

However, one electrode layer in the existing liquid crystal on silicon device is a common electrode, so the existing liquid crystal on silicon device can only adjust the lateral electric field between pixels by controlling the voltage difference between the electrodes in the other electrode layer; Below, the embodiment of the present application can flexibly adjust the lateral electric field between two pixels to flexibly handle the fringe field effect, thereby improving the performance of the LCOS chip.

Description of the drawings

Figure 1 is a top view of WSS in an embodiment of the application;

Figure 2 is a front view of WSS in an embodiment of the application;

3 is a schematic cross-sectional view of the first embodiment of the liquid crystal on silicon device in the first direction in the embodiments of the application;

4 is a schematic cross-sectional view in the second direction of the first embodiment of the liquid crystal on silicon device in the embodiments of the application;

5 is a schematic cross-sectional view in the third direction of the first embodiment of the liquid crystal on silicon device in the embodiments of the application;

Fig. 6 is a schematic diagram of a first embodiment of a pixel in an embodiment of the application;

FIG. 7 is a schematic diagram of a second embodiment of a pixel in an embodiment of the application;

8 is a schematic cross-sectional view of a second embodiment of a liquid crystal on silicon device in an embodiment of the application;

9 is a schematic diagram of a first embodiment of pixel voltage distribution in an embodiment of the application;

10 is a schematic diagram of a first embodiment of pixel voltage distribution in the prior art;

Figure 11 is a schematic diagram of a first embodiment of phase modulation;

12 is a schematic diagram of a second embodiment of pixel voltage distribution in an embodiment of the application;

13 is a schematic cross-sectional view of a third embodiment of a liquid crystal on silicon device in an embodiment of the application;

FIG. 14 is a schematic diagram of a third embodiment of pixel voltage distribution in an embodiment of the application;

15 is a schematic diagram of a second embodiment of pixel voltage distribution in the prior art;

Figure 16 is a schematic diagram of a second embodiment of phase modulation;

FIG. 17 is a schematic diagram of a fourth embodiment of pixel voltage distribution in an embodiment of the application;

18 is a schematic diagram of the first embodiment of the light propagation direction in the embodiment of the application;

FIG. 19 is a schematic diagram of a second embodiment of the light propagation direction in an embodiment of the application;

FIG. 20 is a schematic diagram of a third embodiment of the light propagation direction in an embodiment of the application.

Detailed ways

The embodiments of the present application provide a liquid crystal on silicon device, which is used to flexibly adjust the lateral electric field between two pixels to flexibly handle fringe field effects, thereby improving the performance of the LCOS chip.

The embodiments of the present application can be applied to the wavelength selection module WSS shown in FIG. 1 and FIG. 2. Among them, FIG. 1 is a top view of the WSS in an embodiment of the application, and FIG. 2 is a front view of the WSS in an embodiment of the application. As shown in FIG. 2, the WSS includes a signal port, a collimator lens, a first lens, a second lens, a grating, a third lens, and the liquid crystal on silicon device in the embodiment of the present application, which are sequentially arranged from left to right. The signal ports include A signal input ports and B signal output ports. Each signal input port and each signal output port is equipped with a collimating lens, that is, the number of collimating mirrors is A+B. In the WSS shown in Figure 2, A is 1, and B is 4.

In this embodiment of the application, the collimator lens is used to collimate light. The first lens and the second lens are used to shape the light, for example, can be used to change the size of the light spot. The grating can disperse white light of multiple wavelengths into monochromatic light of multiple wavelengths. Specifically, as shown in FIG. 1, the grating disperses the multi-wavelength light from the signal input port into single-wavelength light with wavelengths R1, R2,... Rn, respectively. The third lens is used to convert the light dispersed by the grating into parallel light in the dispersion direction, and is used to convert the light processed by the liquid crystal on silicon device into parallel light in the port direction.

Liquid crystal on silicon devices are used to modulate the phase of light. Specifically, the liquid crystal on silicon device includes a liquid crystal layer and electrode layers disposed on both sides of the liquid crystal layer, wherein the electrode layers include electrodes. If different voltages are applied to the electrodes on both sides of the liquid crystal layer, a voltage difference can be formed between the two electrodes, which can cause the liquid crystal molecules in the liquid crystal layer to rotate and shift, thereby changing the refraction of light by the liquid crystal molecules. In turn, the modulation of the light phase can be achieved.

Based on the above-mentioned WSS, the working principle of WSS is as follows: As shown in Fig. 2, a beam of light enters from the signal input port, and then enters the grating through the collimator lens, the first lens, and the second lens in sequence. As shown in Fig. 1, when the light passes through the grating, it is dispersed into single-wavelength light with wavelengths R1, R2, ... Rn. Single-wavelength light with wavelengths R1, R2, ... Rn becomes parallel light under the action of the third lens and enters the liquid crystal on silicon device. When light with wavelengths of R1, R2, ... Rn passes through the silicon-based liquid crystal device, the phase changes, and is emitted from the silicon-based liquid crystal device, and then passes through the third lens, grating, second lens, first lens and collimator lens Eject from the signal output port. Among them, single-wavelength light with wavelengths R1, R2, ... Rn can be combined into multi-wavelength light when it passes through the third lens after being emitted from the silicon-based liquid crystal device.

However, in a liquid crystal on silicon device, if the voltage between two adjacent electrodes on the same side of the liquid crystal layer is not equal, then a lateral electric field will be formed between the two pixels where the two electrodes are located, and the lateral electric field can The fringe field effect is produced, that is, the lateral electric field can change the deviation angle of the liquid crystal molecules, thereby affecting the degree of phase modulation of the light. Therefore, the fringe field effect can be dealt with by adjusting the lateral electric field to improve the performance of the LCOS chip.

To this end, an embodiment of the present application provides a liquid crystal on silicon device, in which a plurality of electrodes are provided on each electrode layer. In this way, for any two adjacent pixels, the lateral electric field between the two adjacent pixels can be adjusted by adjusting the voltage difference between the first electrodes in the two pixels, or the two adjacent pixels can be adjusted by adjusting the voltage difference between the first electrodes. The voltage difference between the second electrodes in the pixel adjusts the lateral electric field between the two adjacent pixels. Therefore, in the embodiment of the present application, the lateral electric field between two pixels can be flexibly adjusted to deal with fringe field effects flexibly, thereby improving the performance of the LCOS chip.

Specifically, referring to FIG. 3 to FIG. 5, an embodiment of the present application provides an embodiment of a liquid crystal on silicon device. 3 is a schematic cross-sectional view of a liquid crystal on silicon device in a first direction in an embodiment of the application, FIG. 4 is a schematic cross-sectional view of a liquid crystal on silicon device in a second direction in an embodiment of the application, and FIG. A schematic cross-sectional view of the liquid crystal device in the third direction.

Wherein, the first direction, the second direction and the third direction are perpendicular to each other. In WSS, the first direction may be the port direction shown in FIG. 2; the second direction may be the wavelength dispersion direction shown in FIG. 1.

In this embodiment, the liquid crystal on silicon device includes: a first electrode layer 1, a liquid crystal layer 3, and a second electrode layer 2.

The liquid crystal layer 3 is located between the first electrode layer 1 and the second electrode layer 2.

It should be noted that since the arrangement and connection of the first electrode layer 1, the liquid crystal layer 3, and the second electrode layer 2 are relatively mature technologies, they are not limited here. Generally, as shown in FIG. 1 and FIG. 2, the first electrode layer 1 and the second electrode layer 2 are arranged in parallel.

As shown in FIGS. 3 and 4, the liquid crystal layer 3 contains liquid crystal molecules; since the arrangement positions and offset angles of the liquid crystal molecules are different, the cross-sectional shapes of the liquid crystal molecules in the first direction and the second direction are different.

The first electrode layer 1 includes M first electrodes 11, and the second electrode layer 2 includes N second electrodes 21, where both M and N are positive integers greater than one.

It should be noted that there may be multiple arrangements of the M first electrodes 11, which are not specifically limited in the embodiment of the present application. For example, the M first electrodes 11 may be arranged in an array, wherein the scale of the array may be One row and multiple columns, one column and multiple rows, or multiple rows and multiple columns.

Similarly, there may be multiple arrangements of the N second electrodes 21, which are not specifically limited in the embodiment of the present application. For example, the N second electrodes 21 may also be arranged in an array, wherein the scale of the array can be One row and multiple columns, one column and multiple rows, or multiple rows and multiple columns.

The embodiment of the present application does not specifically limit the number M of the first electrodes 11 and the number N of the second electrodes 21; specifically, the number M of the first electrodes 11 may be equal to or greater than 2; The number N can be equal to two or greater than two. The number M of the first electrodes 11 and the number N of the second electrodes 21 may be equal or not equal.

The embodiment of the present application also does not specifically limit the relative positions of the first electrode 11 and the second electrode 21; for example, the first electrode 11 and the second electrode 21 can be arranged in a staggered manner, that is, the first electrode 11 and the second electrode 21 are in the first electrode 11 and the second electrode 21. The projections in the three directions are partially overlapped; for another example, when M=N, the first electrode 11 and the second electrode 21 can also be arranged symmetrically, that is, the projections of the first electrode 11 and the second electrode 21 in the third direction are completely Coincident.

Taking the silicon-based liquid crystal device shown in FIG. 5 as an example, the first electrode layer 1 includes 25 first electrodes 11, the second electrode layer 2 includes 25 second electrodes 21, 25 first electrodes 11 and 25 second electrodes. The electrodes 21 are all arranged in an array, wherein the scale of the array is five rows and five columns; 25 first electrodes 11 and 25 second electrodes 21 are symmetrically arranged.

The M first electrodes 11, the N second electrodes 21, and the liquid crystal layer 3 between the M first electrodes and the N second electrodes constitute K pixels, where K is a positive integer greater than 1.

Each pixel corresponds to one first electrode 11 and one second electrode 21; and one first electrode 11 can correspond to one pixel or multiple pixels, and one second electrode 21 can correspond to one pixel or multiple pixels. This is related to the relative positions of the first electrode 11 and the second electrode 21.

Specifically, when the first electrode 11 and the second electrode 21 are symmetrically arranged, the first electrode 11 and the second electrode 21 each correspond to only one pixel; when the first electrode 11 and the second electrode 21 are arranged in a staggered manner, the first electrode 11 Corresponding to multiple pixels, the second electrode 21 also corresponds to multiple pixels.

For example, please refer to FIG. 6, which is a schematic diagram of a first embodiment of a pixel in an embodiment of this application. Figure 6 shows two first electrodes 11 and two second electrodes 21, and the first electrode 11 and the second electrode 21 are symmetrically arranged; as can be seen from Figure 6, the two first electrodes 11 and two second electrodes The electrodes 21 constitute two pixels. Specifically, one first electrode 11 and one second electrode 21 constitute one pixel, and the other first electrode 11 and the other second electrode 21 constitute another pixel. Therefore, in this example, each first electrode 11 and each second electrode 21 corresponds to only one pixel.

For another example, please refer to FIG. 7, which is a schematic diagram of a second embodiment of a pixel in an embodiment of this application. Figure 7 shows one first electrode 11 and two second electrodes 21, and the first electrode 11 and the second electrode 21 are arranged in a staggered manner; it can be seen from Figure 7 that one first electrode 11 and two second electrodes The electrodes 21 constitute two pixels. Specifically, a part of the first electrode 11 and a part of a second electrode 21 constitute one pixel, and the other part of the first electrode 11 and a part of the other second electrode 21 constitute another pixel. Pixels. Therefore, in this example, the first electrode 11 corresponds to two pixels. Similarly, it can be known that each second electrode 21 also corresponds to two pixels.

The voltage of the first electrode 11 corresponding to any one of the K pixels is greater than the voltage of the corresponding second electrode 21.

In the embodiment of the present application, the voltages of the M first electrodes 11 in the first electrode layer 1 and the N first electrodes 21 in the second electrode layer 2 can be adjusted according to actual needs, so for any two phases The adjacent pixels can be adjusted by adjusting the voltage difference between the first electrodes 11 in the two pixels to adjust the lateral electric field between the two adjacent pixels, or by adjusting the second electrode 21 in the two pixels. The voltage difference between the two adjacent pixels is used to adjust the lateral electric field between the two adjacent pixels; therefore, the embodiment of the present application can flexibly adjust the lateral electric field between the two pixels to flexibly handle the fringe field effect, thereby improving the performance of the LCOS chip .

Based on the above description, the voltages of the M first electrodes 11 in the first electrode layer 1 and the N second electrodes 21 in the second electrode layer 2 can be adjusted according to actual needs. Therefore, the voltages of the M first electrodes 11 There are many situations for the voltage and the voltage of the N second electrodes 21. The specific introduction is given below.

In another embodiment of the liquid crystal on silicon device provided by the embodiment of the present application, there are two adjacent first electrodes 11 with unequal voltages among the M first electrodes 11.

It can be understood that the embodiment of the present application is not limited to only two adjacent first electrodes 11 with unequal voltages among the M first electrodes 11. Specifically, if two adjacent first electrodes 11 with unequal voltages are recorded as a pair of first electrodes 11, then there may be a pair of first electrodes 11 in the M first electrodes 11, or there may be two pairs or More than two pairs of first electrodes 11.

There are two adjacent second electrodes 21 with unequal voltages among the N second electrodes 21; similarly, the embodiment of the present application is not limited to only two adjacent second electrodes 21 with unequal voltages among N. Specifically, if two adjacent second electrodes 21 with unequal voltages are recorded as a pair of second electrodes 21, then there may be a pair of second electrodes 21 in the N second electrodes 21, or there may be two pairs or More than two pairs of second electrodes 21.

In the embodiment of the present application, by controlling the voltages of the two adjacent first electrodes 11 to be unequal, and controlling the voltages of the two adjacent second electrodes 21 to be unequal, it is possible to achieve a reduction in the lateral electric field in the liquid crystal on silicon device. Adjustment.

Based on the above description of the corresponding relationship between the pixel and the first electrode 11, and the corresponding relationship between the pixel and the second electrode 21, it can be seen that two adjacent first electrodes 11 and two adjacent first electrodes 11 with unequal voltages The second electrodes 21 with unequal voltages may constitute two pixels.

Specifically, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the K pixels include a first pixel and a second pixel.

The first electrode 11 corresponding to the first pixel is adjacent to the first electrode 11 corresponding to the second pixel and the voltages are not equal;

The second electrode 21 corresponding to the first pixel is adjacent to the second electrode 21 corresponding to the second pixel and the voltages are not equal.

For example, please refer to FIG. 8, which is a schematic cross-sectional view of a second embodiment of a liquid crystal on silicon device in an embodiment of the application. In FIG. 8, ten first electrodes 11 and ten second electrodes 21 constitute ten pixels, and the first pixel and the second pixel are two adjacent pixels in the ten pixels.

In the embodiment of the present application, it is possible to control the voltages of the first electrode 11 corresponding to the first pixel and the first electrode 11 corresponding to the second pixel to be unequal, and to control the second electrode 21 corresponding to the first pixel and the voltage corresponding to the second pixel at the same time. The voltage of the second electrode 21 is not equal to adjust the lateral electric field between the first pixel and the second pixel.

Based on the foregoing description and FIG. 1, it can be seen that the liquid crystal on silicon device can modulate the phase of light of multiple wavelengths. Therefore, based on the foregoing embodiment, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first pixel and the second pixel are used to modulate the phase of light of the same wavelength.

It is understandable that if the first pixel and the second pixel are used to modulate the phase of light of the same wavelength, the light of the same wavelength will pass through the portion of the liquid crystal layer 3 corresponding to the first pixel during the propagation process. Pass through the 3 part of the liquid crystal layer corresponding to the second pixel.

In addition, the first pixel and the second pixel can also be used to modulate the phase of light of different wavelengths; specifically, light of one wavelength will pass through the portion of the liquid crystal layer corresponding to the first pixel during the propagation process, but It does not pass through the portion of the liquid crystal layer corresponding to the second pixel; while the light of another wavelength passes through the portion of the liquid crystal layer 3 corresponding to the first pixel during the propagation process, it does not pass through the portion of the liquid crystal layer corresponding to the second pixel.

It should be understood that the number of pixels used to modulate the phase of light of the same wavelength may be multiple, and it is assumed here that H pixels of the K pixels are used to modulate light of a certain wavelength. Wherein, H is an integer greater than 1.

In order to periodically modulate the phase of the light of this wavelength to generate a periodic phase delay, the voltage difference of the H pixels is usually controlled to be periodically distributed. Specifically, the voltage difference of the H pixels arranged in sequence is periodically distributed with F pixels as a period, and the phase delay of the light of this wavelength also changes periodically with F pixels as a period.

Taking the liquid crystal on silicon device shown in FIG. 8 as an example, the liquid crystal on silicon device includes a total of 10 pixels, and the voltage difference of these 10 pixels is periodically distributed; specifically, every 5 pixels can be a period, so the figure The voltage difference of the 10 pixels shown in 8 is periodically distributed with 5 pixels as a period. Correspondingly, the phase delay generated by these 10 pixels also changes periodically with 5 pixels as a period.

In order to facilitate the subsequent description, the concept of grating period is introduced here. The grating period refers to the distance between two pixels with the same phase delay. Based on the foregoing description, it can be seen that the phase delay generated in the H pixels arranged in sequence is periodically distributed with F pixels as a period, so it can be considered that each F pixels corresponds to a grating period. As shown in Fig. 8, 5 of the pixels correspond to the first grating period, and the other 5 pixels correspond to the second grating period.

Based on the above analysis, it can be known that, by way of example, if the first pixel and the second pixel are used to modulate the phase of light of the same wavelength, the first pixel and the second pixel may correspond to the same grating period.

When the first pixel and the second pixel correspond to the same grating period, the voltage difference between the first electrode 11 corresponding to the first pixel and the first electrode 11 corresponding to the second pixel is controlled, and the second pixel corresponding to the first pixel is controlled. The voltage difference between the electrode 21 and the second electrode 21 corresponding to the second pixel can adjust the lateral electric field in one grating period.

Exemplarily, if the first pixel and the second pixel are used to modulate the phase of light of the same wavelength, the first pixel and the second pixel may also correspond to different grating periods. For example, as shown in FIG. 8, the first pixel corresponds to the first grating period, and the second pixel corresponds to the second grating period.

When the first pixel and the second pixel correspond to different grating periods, the voltage between the first electrode 11 corresponding to the first pixel in the first grating period and the first electrode 11 corresponding to the second pixel in the second grating period is controlled. And control the voltage difference between the second electrode 21 corresponding to the first pixel in the first grating period and the second electrode 21 corresponding to the second pixel in the second grating period. The lateral electric field is adjusted.

Based on the foregoing description, it can be known that the lateral electric field can change the deviation angle of the liquid crystal molecules, thereby affecting the degree of modulation of the phase of the light by the liquid crystal molecules.

It should be noted that the influence of the lateral electric field on the degree of modulation of the phase of light includes two situations: one is that the lateral electric field is beneficial to the modulation of the phase, and the other is that the lateral electric field is not conducive to the modulation of the phase. The modulation that is beneficial to the phase is related to the initial arrangement of the liquid crystal molecules. If the transverse electric field is conducive to the modulation of the phase, you can strengthen the transverse electric field to better modulate the phase of the light; if the transverse electric field is not conducive to the modulation of the phase, you can reduce the influence of the transverse electric field on the phase modulation by weakening the transverse electric field .

Specifically, based on the foregoing embodiments, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the voltage of the first electrode 11 corresponding to the first pixel is greater than the voltage of the first electrode 11 corresponding to the second pixel The voltage of the second electrode 21 corresponding to the first pixel is smaller than the voltage of the second electrode 21 corresponding to the second pixel.

Since the voltage of the first electrode 11 corresponding to the first pixel is greater than the voltage of the first electrode 11 corresponding to the second pixel, the direction of the electric field between the first electrode 11 corresponding to the first pixel and the first electrode 11 corresponding to the second pixel is The first pixel points to the second pixel; since the voltage of the second electrode 21 corresponding to the first pixel is lower than the voltage of the second electrode 21 corresponding to the second pixel, the second electrode 21 corresponding to the first pixel corresponds to the second pixel The direction of the electric field between the second electrodes 21 is from the second pixel to the first pixel. It can be seen that the directions of the above two electric fields are opposite, and therefore can play a role in weakening the lateral electric field between the first pixel and the second pixel.

Based on the embodiment of the present application, it can play a role in weakening the lateral electric field between the first pixel and the second pixel. Therefore, the embodiment of the present application is suitable for scenarios where the lateral electric field is not conducive to phase modulation, that is, by weakening the first pixel and the second pixel. The transverse electric field in between reduces the influence of the transverse electric field on the phase modulation, thereby suppressing the fringe field effect.

In order to suppress the fringe field effect as much as possible, based on the above embodiment, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first electrode 11 corresponding to the first pixel and the first electrode corresponding to the second pixel are The voltage difference between 11 is equal to the voltage difference between the second electrode 21 corresponding to the second pixel and the second electrode 21 corresponding to the first pixel.

In the embodiment of the present application, since the voltage difference between the first electrode 11 corresponding to the first pixel and the first electrode 11 corresponding to the second pixel is equal to that, the second electrode 21 corresponding to the second pixel corresponds to the first pixel corresponding to the first pixel. The voltage difference between the two electrodes 21 can further weaken the transverse electric field, thereby weakening the influence of the transverse electric field on the phase modulation.

The following specific examples illustrate that the embodiment of the present application can weaken the lateral electric field between the first pixel and the second pixel, so as to suppress the fringe field effect.

First example:

The following first explains that the embodiment of the present application can weaken the lateral electric field between the first pixel and the second pixel.

Please refer to FIGS. 9 and 10. FIG. 9 is a schematic diagram of a first embodiment of pixel voltage distribution in an embodiment of the application, and FIG. 10 is a schematic diagram of a first embodiment of pixel voltage distribution in the prior art.

In FIGS. 9 and 10, pixel positions are used to represent pixels, and the 10 pixels in FIG. 8 correspond to pixel position 1 to pixel position 10 in order from left to right. Among them, the first pixel in FIG. 8 corresponds to pixel position 5, and the second pixel in FIG. 8 corresponds to pixel position 6.

Figures 9 and 10 both show the voltage of the first electrode 11 and the voltage of the second electrode 21 in each pixel; it can be seen from Figures 9 and 10 that the voltage of the first electrode 11 in each pixel is both It is greater than the voltage of the second electrode 21.

Set each pixel in FIG. 8 according to the voltage value shown in FIG. 9, the voltage of the first electrode 11 in the first pixel is 2.5V, the voltage of the first electrode 11 in the second pixel is 1.8V, and the voltage of the first pixel is 1.8V. The voltage of the second electrode 21 in the middle is 0V, and the voltage of the first electrode 11 in the second pixel is 0.7V. The difference between the voltage of the first electrode 11 in the first pixel and the voltage of the first electrode 11 in the second pixel is 0.7V, and the voltage of the second electrode 21 in the second pixel is greater than the voltage of the second electrode 21 in the first pixel. The difference is also 0.7V.

If each pixel in FIG. 8 is set according to the voltage value shown in FIG. 10, the voltage of the first electrode 11 in the first pixel is 2.5V, and the voltage of the first electrode 11 in the second pixel is 1.1V; In some liquid crystal on silicon devices, the second electrode layer 2 is a common electrode, so the voltage of the second electrode 21 in the first pixel is 0V, and the voltage of the second electrode 21 in the second pixel is also 0V. The difference between the voltage of the first electrode 11 in the first pixel and the voltage of the first electrode 11 in the second pixel is 1.4V. The voltage of the second electrode 21 in the second pixel is equal to that of the second electrode 21 in the first pixel. The difference is 0V.

Based on the above analysis, it can be known that the embodiment of the present application can weaken the lateral electric field between the first pixel and the second pixel.

The following further explains that weakening the lateral electric field between the first pixel and the second pixel can suppress the fringe field effect.

Specifically, each pixel in FIG. 8 is set according to the voltage values shown in FIG. 9 and FIG. 10, and then the light of the same wavelength is phase modulated, and the modulation result is shown in FIG. 11. Fig. 11 is a schematic diagram of the first embodiment of phase modulation.

In this example, the increment of the optical path is used to indicate the magnitude of the phase delay. Specifically, the greater the increment of the optical path, the greater the phase delay. For the liquid crystal on silicon device shown in FIG. 8, the greater the voltage difference of the pixel, the greater the deviation angle of the liquid crystal molecules, and the smaller the phase retardation.

In FIG. 11, the solid curve represents the increase in the optical path length generated by setting each pixel in FIG. 8 according to the voltage value shown in FIG. The increment of the optical path generated by each pixel in the setting.

In Figure 11, the pixel length is used to represent the pixel, and each pixel corresponds to a pixel length of 6.4μm; combining the pixel positions in Figure 9 and Figure 10, in this example, the pixel length 0 to 6.4μm corresponds to pixel position 1. A length of 6.4 μm to 12.8 μm corresponds to pixel position 2, and so on, a pixel length of 25.6 μm to 32 μm corresponds to pixel position 5 (corresponding to the first pixel), and a pixel length of 32 μm to 38.4 μm corresponds to pixel position 6 (corresponding to the second pixel).

Based on the foregoing description, setting each pixel in FIG. 8 according to the voltage value shown in FIG. 9 is compared with setting each pixel in FIG. 8 according to the voltage value shown in FIG. The lateral electric field between the first pixel and the second pixel shown in FIG. 11 is weakened, and the lateral electric field between the first pixel and the second pixel is weakened. It will cause the increase of the optical path to increase (indicating the increase of the phase delay), the increase of the phase modulation depth, and the narrowing of the flyback width of the conversion area; among them, the phase modulation depth is the maximum value of the phase delay and the minimum value of the phase delay. Difference, the flyback width of the conversion area is the distance between the position of the maximum value of the phase delay and the position of the minimum value of the phase delay. It can be seen that, in the embodiment of the present application, weakening the lateral electric field between the first pixel and the second pixel can increase the phase modulation depth and reduce the flyback width of the conversion area, that is, the fringe field effect can be suppressed.

In combination with Figure 8, Figure 8 shows that the pixel voltage difference gradually increases during the grating period (take the first grating period as an example, the voltage difference of the pixel gradually increases from left to right, where the voltage difference of the first pixel is the largest) An example of the ideal phase delay curve at this time. At this time, the phase modulation depth is the largest, and the flyback width of the conversion area is the narrowest (which can be regarded as 0); comparing Fig. 11 and Fig. 8, it can be seen that the solid line curve is more than the dashed curve. Close to the ideal phase delay curve in Figure 8, it can also be seen that weakening the lateral electric field between the first pixel and the second pixel can increase the phase modulation depth and reduce the flyback width of the conversion area, that is, Can suppress fringe field effects.

It should be noted that in addition to the pixel voltage distribution scheme shown in FIG. 9, there may also be multiple pixel voltage distribution schemes, which can make the voltage of the first electrode 11 corresponding to the first pixel greater than that of the first electrode 11 corresponding to the second pixel. The voltage of the second electrode 21 corresponding to the first pixel is smaller than the voltage of the second electrode 21 corresponding to the second pixel, which is not limited in the embodiment of the present application.

In FIG. 8, the first pixel belongs to the first grating period, and the second pixel belongs to the second grating period. The pixel voltage loaded by each pixel in FIG. 8 can be as shown in FIG. 9. As shown in FIG. 12, if the first pixel belongs to the second grating period and the second pixel belongs to the first grating period, the pixel voltage applied to each pixel in FIG. 12 may be as shown in FIG.

Specifically, FIG. 13 is a schematic diagram of a second embodiment of pixel voltage distribution in an embodiment of the application. FIG. 13 shows the voltage of the first electrode 11 and the voltage of the second electrode 21 in each pixel; it can be seen from FIG. 13 That is, the voltage of the first electrode 11 in each pixel is greater than the voltage of the second electrode 21.

If each pixel in FIG. 12 is set according to the voltage value shown in FIG. 13, the voltage of the first electrode 11 in the first pixel is 2.5V, and the voltage of the first electrode 11 in the second pixel is 1.8V. The voltage of the second electrode 21 in the first pixel is 0V, and the voltage of the first electrode 11 in the second pixel is 0.7V. The difference between the voltage of the first electrode 11 in the first pixel and the voltage of the first electrode 11 in the second pixel is 0.7V, and the voltage of the second electrode 21 in the second pixel is greater than the voltage of the second electrode 21 in the first pixel. The difference is also 0.7V.

Similar to the foregoing embodiment, the embodiment of the present application can also weaken the lateral electric field between the first pixel and the second pixel, and can suppress the fringe field effect.

Specifically, based on the foregoing embodiments, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the voltage of the first electrode 11 corresponding to the first pixel is lower than the voltage of the first electrode 11 corresponding to the second pixel ; The voltage of the second electrode 21 corresponding to the first pixel is less than the voltage of the second electrode 21 corresponding to the second pixel.

Since the voltage of the first electrode 11 corresponding to the first pixel is smaller than the voltage of the first electrode 11 corresponding to the second pixel, the electric field direction between the first electrode 11 corresponding to the first pixel and the first electrode 11 corresponding to the second pixel is The second pixel points to the first pixel; since the voltage of the second electrode 21 corresponding to the first pixel is also lower than the voltage of the second electrode 21 corresponding to the second pixel, the second electrode 21 corresponding to the first pixel is The direction of the electric field between the corresponding second electrodes 21 is also directed from the second pixel to the first pixel. It can be seen that the directions of the above two electric fields are the same, and therefore can play a role in enhancing the lateral electric field between the first pixel and the second pixel.

Based on the embodiment of the present application, the effect of the lateral electric field between the first pixel and the second pixel can be enhanced. Therefore, the embodiment of the present application is suitable for scenarios where the lateral electric field facilitates phase modulation, that is, by enhancing the effect between the first pixel and the second pixel. Lateral electric field to better modulate the phase of light.

In order to further enhance the lateral electric field between the first pixel and the second pixel, based on the above embodiment, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first electrode 11 and the second pixel corresponding to the second pixel are The voltage difference between the first electrode 11 corresponding to one pixel is greater than the first preset value; the voltage difference between the second electrode 21 corresponding to the second pixel and the second electrode 21 corresponding to the first pixel is greater than the second preset value .

In the embodiment of the present application, the voltage difference between the first electrode 11 corresponding to the second pixel and the first electrode 11 corresponding to the first pixel is greater than the first preset value, and the second electrode 21 corresponding to the second pixel is greater than the first electrode 11 corresponding to the first pixel. The voltage difference between the second electrodes 21 corresponding to a pixel is greater than the second preset value, so that the lateral electric field is stronger, and the phase of the light is better modulated.

The following specific examples are used to illustrate that the implementation of this application can enhance the lateral electric field between the first pixel and the second pixel, and facilitate the modulation of the phase of light.

Second example:

The following first explains that the embodiment of the present application can enhance the lateral electric field between the first pixel and the second pixel.

Please refer to FIGS. 14 and 15. FIG. 14 is a schematic diagram of a third embodiment of pixel voltage distribution in an embodiment of this application, and FIG. 15 is a schematic diagram of a second embodiment of pixel voltage distribution in the prior art.

In FIGS. 14 and 15, pixel positions are used to represent pixels, and the 10 pixels in FIG. 8 correspond to pixel position 1 to pixel position 10 in order from left to right. Among them, the first pixel in FIG. 8 corresponds to pixel position 5, and the second pixel in FIG. 8 corresponds to pixel position 6.

FIGS. 14 and 15 both show the voltage of the first electrode 11 and the voltage of the second electrode 21 in each pixel; it can be seen from FIGS. 14 and 15 that the voltage of the first electrode 11 in each pixel is both It is greater than the voltage of the second electrode 21.

If each pixel in FIG. 8 is set according to the voltage value shown in FIG. 14, the voltage of the first electrode 11 in the first pixel is 1.1V, the voltage of the first electrode 11 in the second pixel is 3V, and the voltage of the first pixel is 3V. The voltage of the second electrode 21 in the middle is 0V, and the voltage of the first electrode 11 in the second pixel is 0.4V. The difference between the voltage of the first electrode 11 in the second pixel and the voltage of the first electrode 11 in the first pixel is 1.9V, and the voltage of the second electrode 21 in the second pixel is greater than the voltage of the second electrode 21 in the first pixel. The difference is 0.4V.

If each pixel in FIG. 8 is set according to the voltage value shown in FIG. 15, the voltage of the first electrode 11 in the first pixel is 1.1V, and the voltage of the first electrode 11 in the second pixel is 2.6V; In some liquid crystal on silicon devices, the second electrode layer 2 is a common electrode, so the voltage of the second electrode 21 in the first pixel is 0V, and the voltage of the second electrode 21 in the second pixel is also 0V. The difference between the voltage of the first electrode 11 in the second pixel and the voltage of the first electrode 11 in the first pixel is 1.4V. The voltage of the second electrode 21 in the second pixel is greater than the voltage of the second electrode 21 in the first pixel. The difference is 0V.

Based on the above analysis, it can be known that the embodiment of the present application can strengthen the lateral electric field between the first pixel and the second pixel.

The following further explains that strengthening the lateral electric field between the first pixel and the second pixel is beneficial to modulating the phase of light.

Specifically, each pixel in FIG. 8 is set according to the voltage values shown in FIG. 14 and FIG. 15 respectively, and then the light of the same wavelength is phase-modulated, and the modulation result is shown in FIG. 16. Figure 16 is a schematic diagram of the second embodiment of phase modulation.

In FIG. 16, the solid line represents the phase modulation result of setting each pixel in FIG. 8 according to the voltage value shown in FIG. 14, and the dotted line represents the setting of each pixel in FIG. 8 according to the voltage value shown in FIG. 15. After the phase modulation result.

In Figure 16, the pixel length is used to represent the pixel, and the pixel length corresponding to each pixel is 6.4μm; combining the pixel positions in Figure 14 and Figure 15, in this example, the pixel length 0 to 6.4μm corresponds to the pixel position 1, and the pixel A length of 6.4 μm to 12.8 μm corresponds to pixel position 2, and so on, a pixel length of 25.6 μm to 32 μm corresponds to pixel position 5 (corresponding to the first pixel), and a pixel length of 32 μm to 38.4 μm corresponds to pixel position 6 (corresponding to the second pixel).

Based on the foregoing description, setting each pixel in FIG. 8 according to the voltage value shown in FIG. 14 is compared with setting each pixel in FIG. 8 according to the voltage value shown in FIG. The horizontal electric field between the first pixel and the second pixel shown in FIG. 16 is increased, and the increase in the optical path between the first pixel and the second pixel shows that the horizontal electric field between the first pixel and the second pixel is enhanced. It will result in a large increase in the optical path (indicating an increase in the phase delay), an increase in the phase modulation depth, and a narrower flyback width of the conversion area; where the phase modulation depth is the difference between the maximum value of the phase delay and the minimum value of the phase delay Value, the flyback width of the conversion area is the distance between the position of the maximum value of the phase delay and the position of the minimum value of the phase delay.

It can be seen from this that, in the embodiment of the present application, strengthening the lateral electric field between the first pixel and the second pixel can increase the phase modulation depth and reduce the flyback width of the conversion area, so it is beneficial to modulate the phase of light.

It should be noted that, in addition to the pixel voltage distribution scheme shown in FIG. 14, there may also be multiple pixel voltage distribution schemes, which can make the voltage of the first electrode 11 corresponding to the first pixel smaller than that of the first electrode 11 corresponding to the second pixel. The voltage of the second electrode 21 corresponding to the first pixel is smaller than the voltage of the second electrode 21 corresponding to the second pixel, which is not limited in the embodiment of the present application.

In FIG. 8, the first pixel belongs to the first grating period, and the second pixel belongs to the second grating period. The pixel voltage loaded by each pixel in FIG. 8 may be as shown in FIG. 14. As shown in FIG. 12, if the first pixel belongs to the second grating period and the first pixel belongs to the second grating period, the pixel voltage applied to each pixel in FIG. 12 may be as shown in FIG. 17.

Specifically, FIG. 17 is a schematic diagram of a fourth embodiment of pixel voltage distribution in an embodiment of the application. FIG. 17 shows the voltage of the first electrode 11 and the voltage of the second electrode 21 in each pixel; it can be seen from FIG. 17 That is, the voltage of the first electrode 11 in each pixel is greater than the voltage of the second electrode 21.

If each pixel in FIG. 8 is set according to the voltage value shown in FIG. 17, similarly, the voltage of the first electrode 11 in the first pixel is 1.1V, and the voltage of the first electrode 11 in the second pixel is 2.6V; Since the second electrode layer 2 in the existing liquid crystal on silicon device is a common electrode, the voltage of the second electrode 21 in the first pixel is 0V, and the voltage of the second electrode 21 in the second pixel is also 0V. The difference between the voltage of the first electrode 11 in the second pixel and the voltage of the first electrode 11 in the first pixel is 1.4V. The voltage of the second electrode 21 in the second pixel is greater than the voltage of the second electrode 21 in the first pixel. The difference is 0V.

Similar to the foregoing embodiment, the embodiment of the present application can also strengthen the lateral electric field between the first pixel and the second pixel, and is beneficial to modulating the phase of light.

The voltage distribution of the first electrode 11 in the first electrode layer 1 and the voltage distribution of the second electrode 21 in the second electrode layer 2 are described above. Optical properties are explained.

Based on the foregoing various embodiments, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first electrode layer 1 is a light-transmitting electrode layer, and the second electrode layer 2 is a light-transmitting electrode layer.

In the embodiments of the present application, the light-transmitting electrode layer refers to an electrode layer that allows light to pass through, so both the first electrode 11 and the second electrode 21 need to have light-transmitting properties.

As shown in FIG. 18, in the embodiment of the present application, when the first electrode layer 1 is a light-transmitting electrode layer, and the second electrode layer 2 is a light-transmitting electrode layer, light can enter the liquid crystal layer from the first electrode layer 1. 3, then pass through the liquid crystal layer 3, and finally exit from the second electrode layer 2.

Based on the foregoing embodiments, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first electrode layer 1 is a light-transmitting electrode layer, and the second electrode layer 2 is a reflective electrode layer; or

The first electrode layer 1 is a reflective electrode layer, and the second electrode layer 2 is a light-transmitting electrode layer.

Here, the reflective electrode layer refers to an electrode layer capable of reflecting light.

When the first electrode layer 1 is a reflective electrode layer, the first electrode 11 needs to be reflective; specifically, a layer of reflective material can be covered on the surface of the first electrode 11 to make the first electrode 11 reflective; the reflective material can be There are many options, which are not detailed here.

It should be noted that the light-transmitting electrode layer in the embodiment of the present application can be understood with reference to the relevant description of the light-transmitting electrode layer in the foregoing embodiment.

As shown in FIG. 19, when the first electrode layer 1 is a light-transmitting electrode layer and the second electrode layer 2 is a reflective electrode layer, light can enter the liquid crystal layer 3 from the first electrode layer 1, and then pass through the liquid crystal layer 3. , And reflect at the second electrode layer 2, then pass through the liquid crystal layer 3 again, and finally exit from the first electrode layer 1.

Similarly, when the first electrode layer 1 is a reflective electrode layer and the second electrode layer 2 is a light-transmitting electrode layer, light can enter the liquid crystal layer 3 from the second electrode layer 2, and then pass through the liquid crystal layer 3, and The reflection occurs at the first electrode layer 1, and then passes through the liquid crystal layer 3 again, and finally exits from the second electrode layer 2.

Based on the foregoing embodiments, in another embodiment of the liquid crystal on silicon device provided in the embodiment of the present application, the first electrode layer 1 is a reflective electrode layer, and the second electrode layer 2 is a reflective electrode layer.

Since the first electrode layer 1 and the second electrode layer 2 are both reflective electrode layers, both the first electrode 11 and the second electrode 21 need to be reflective; specifically, the surfaces of the first electrode 11 and the second electrode 21 can be covered A layer of light-reflecting material makes the first electrode 11 and the second electrode 21 have light-reflective properties. There are many options for reflective materials, which will not be detailed here.

As shown in FIG. 20, when the first electrode layer 1 is a reflective electrode layer and the second electrode layer 2 is a reflective electrode layer, light can enter the liquid crystal layer 3 from one side of the liquid crystal layer 3, and then on the first electrode layer 1. The first reflection occurs, and after passing through the liquid crystal layer 3 again, a second reflection occurs on the second electrode layer 2, and finally passes through the liquid crystal layer 3 and exits from the other side of the liquid crystal layer 3.

The first electrode layer 1, the liquid crystal layer 3, and the second electrode layer 2 in the liquid crystal on silicon device are described above, and the other components in the liquid crystal on silicon device are described below.

As shown in FIGS. 3 and 4, in another embodiment of the liquid crystal on silicon device provided by the embodiment of the present application, the liquid crystal on silicon device may further include a cover plate, an alignment layer, and a substrate.

Specifically, the second electrode layer 2 may be provided on the substrate; a calibration layer is provided between the first electrode layer 1 and the liquid crystal layer 3, and a calibration layer is also provided between the second electrode layer 2 and the liquid crystal layer 3; cover The plate is arranged on one side of the first electrode layer 1, and the first electrode layer 1 is located between the cover plate and the calibration layer.

Among them, the alignment layer between the first electrode layer 1 and the liquid crystal layer 3, and the alignment layer between the second electrode layer 2 and the liquid crystal layer 3, are used to make the liquid crystal molecules in the liquid crystal layer 3 follow a preset direction Offset the preset tilt angle and preset twist angle.

It should be noted that the tilt angle and the twist angle refer to the offset angle of the liquid crystal molecules in two vertical planes. For example, assuming that the twist angle refers to the angle at which the liquid crystal molecules deviate in the horizontal plane, the tilt angle may refer to the angle at which the liquid crystal molecules deviate in the vertical plane.

Normally, relying on the calibration layer, the liquid crystal molecules can be shifted to a preset twist angle, and the calibration layer can shift the liquid crystal molecules to a preset tilt angle. To make the liquid crystal molecules continue to shift to the required tilt angle on the basis of the preset tilt angle, based on the function of the alignment layer, it is also necessary to apply a voltage on both sides of the liquid crystal layer 3 to apply a voltage to both sides of the liquid crystal layer 3. A voltage difference is formed on the sides. Therefore, the offset angle mentioned in the foregoing various embodiments can be understood as the inclination angle in this embodiment.

Based on the foregoing description, the first electrode layer 1 may be a light-transmitting electrode layer or a reflective electrode layer; similarly, the second electrode layer 2 may be a light-transmitting electrode layer or a reflective electrode layer.

In the embodiment of the present application, when the first electrode layer 1 is a light-transmitting electrode layer and the second electrode layer 2 is a light-transmitting electrode layer, in order to ensure that light can pass through the cover plate and then enter the first electrode layer 1, and can Pass through the second electrode layer 2 and then eject from the substrate. The cover plate needs to be a light-transmitting cover plate, and the substrate needs to be a light-transmitting substrate; when the first electrode layer 1 is a reflective electrode layer, and the second electrode layer 2 is a reflective electrode In order to ensure that light does not exit the cover plate from the gap between the first electrodes 11 and the substrate from the gap between the second electrodes 21, the cover plate needs to be a reflective cover plate, and the substrate needs to be reflective Substrate; when the first electrode layer 1 is a light-transmitting electrode layer, and the second electrode layer 2 is a reflective electrode layer, in order to ensure that light can pass through the cover plate and then enter the first electrode layer 1, and not from the second electrode The gap between 21 emits the substrate, the cover needs to be a transparent cover, and the substrate needs to be a reflective substrate; when the first electrode layer 1 is a reflective electrode layer, and the second electrode layer 2 is a transparent electrode layer, It is ensured that light can pass through the substrate and then enter the second electrode layer 2 without emitting the cover plate from the gap between the first electrodes 11. The cover plate needs to be a reflective cover plate, and the substrate needs to be a light-transmitting substrate.

Among them, when the substrate is a reflective substrate, the material of the substrate can be silicon; when the substrate is a light-transmitting substrate, the material of the substrate can be glass; similarly, when the cover is a reflective cover, the material of the cover can be silicon ; When the cover is a transparent cover, the material of the cover can be glass.

It should be noted that the arrow directions in FIG. 18, FIG. 19, and FIG. 20 only indicate the approximate propagation direction of light, and are not used to indicate the accurate propagation path of light. In addition, FIG. 18, FIG. 19, and FIG. 20 do not show the calibration layer. Since the calibration layer is located between the electrode layer (including the first electrode layer 1 and the second electrode layer 2) and the liquid crystal layer 3, the calibration layer is shown in FIGS. In each embodiment corresponding to FIG. 20, the alignment layer is transparent.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the embodiments of this application and the above-mentioned drawings are not used to describe a specific sequence or sequence. order. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in a sequence other than the content illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive solutions. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those clearly listed. Steps or units, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

Claims

A liquid crystal on silicon device, characterized by comprising: a first electrode layer, a liquid crystal layer, and a second electrode layer;

The liquid crystal layer is located between the first electrode layer and the second electrode layer;

The first electrode layer includes M first electrodes, and the second electrode layer includes N second electrodes, wherein both M and N are positive integers greater than 1;

The M first electrodes, the N second electrodes, and the liquid crystal layer between the M first electrodes and the N second electrodes constitute K pixels, wherein each pixel corresponds to a first Electrode and a second electrode, K is a positive integer greater than 1;

The voltage of the first electrode corresponding to any one of the K pixels is greater than the voltage of the corresponding second electrode.
The liquid crystal on silicon device according to claim 1, wherein there are two adjacent first electrodes with unequal voltages among the M first electrodes;

There are two adjacent second electrodes with unequal voltages among the N second electrodes.
The liquid crystal on silicon device according to claim 2, wherein the K pixels include a first pixel and a second pixel;

The first electrode corresponding to the first pixel is adjacent to the first electrode corresponding to the second pixel and the voltages are not equal;

The second electrode corresponding to the first pixel is adjacent to the second electrode corresponding to the second pixel and the voltages are not equal.
3. The liquid crystal on silicon device according to claim 3, wherein the first pixel and the second pixel are used to modulate the phase of light of the same wavelength.
4. The liquid crystal on silicon device according to claim 4, wherein the first pixel and the second pixel correspond to the same grating period.
4. The liquid crystal on silicon device according to claim 4, wherein the first pixel and the second pixel correspond to different grating periods.
7. The liquid crystal on silicon device according to any one of claims 3 to 6, wherein the voltage of the first electrode corresponding to the first pixel is greater than the voltage of the first electrode corresponding to the second pixel;

The voltage of the second electrode corresponding to the first pixel is smaller than the voltage of the second electrode corresponding to the second pixel.
7. The liquid crystal on silicon device according to claim 7, wherein the voltage difference between the first electrode corresponding to the first pixel and the first electrode corresponding to the second pixel is equal to, and the second pixel corresponds to The voltage difference between the second electrode of the first pixel and the second electrode corresponding to the first pixel.
The liquid crystal on silicon device according to any one of claims 3 to 6, wherein the voltage of the first electrode corresponding to the first pixel is less than the voltage of the first electrode corresponding to the second pixel;

The voltage of the second electrode corresponding to the first pixel is smaller than the voltage of the second electrode corresponding to the second pixel.
The liquid crystal on silicon device according to any one of claims 1 to 9, wherein the first electrode layer is a light-transmitting electrode layer, and the second electrode layer is a light-transmitting electrode layer.
The liquid crystal on silicon device according to any one of claims 1 to 9, wherein the first electrode layer is a light-transmitting electrode layer, and the second electrode layer is a reflective electrode layer; or

The first electrode layer is a reflective electrode layer, and the second electrode layer is a light-transmitting electrode layer.
The liquid crystal on silicon device according to any one of claims 1 to 9, wherein the first electrode layer is a reflective electrode layer, and the second electrode layer is a reflective electrode layer.