WO2021244036A1 - Grating array, 3d display device, and 3d display method - Google Patents

Abstract

A grating array, a 3D display device, and a 3D display method. The grating array comprises an input grating array (310) and an output grating array (320) which are provided on a waveguide substrate (300); the input grating array (310) couples incident light into the waveguide substrate (300) and maintains angle phase information of the incident light; the output grating array (320) is used for coupling and outputting the light from the waveguide substrate (300) and maintaining the angle phase information of the incident light. By means of the input grating array (310) and the output grating array (320) which are provided on the waveguide substrate (300), the angle phase information of the incident light is restored. The whole device is light and thin, matching of multiple layers of waveguides is not needed, and the machining difficulty is reduced.

Description

Grating array, 3D display device and 3D display method Technical field

The invention relates to the field of optoelectronic devices, in particular to a grating array, a 3D display device and a 3D display method.

Background technique

At present, the mainstream solutions for realizing 3D display are the glasses type and the naked eye type.

The glasses type are more representative of the chromatic aberration type, polarized light type and active shutter type. The principle is the same. They all use the parallax of the human eye to project the corresponding images of the left eye and the right eye to the left and right eyes. The brain sends these two images. The picture is integrated into a picture with spatial depth. Since the 3D display realized by this principle is a three-dimensional effect synthesized by the brain, in the viewing process, if the time is too long, there will be a feeling of discomfort.

The representative of the naked-eye type is the holographic display. Compared with the glasses type, its advantage is that it can provide full physical depth of field and a true three-dimensional display. The disadvantage is that the dynamic refresh frequency of the holographic material is not enough, and it cannot be used for large-scale commercial applications.

Due to the above-mentioned problems of traditional 3D display, some institutions such as MagicLeap try to use the method of reproducing the light field to realize the scene with real depth information. Although it allows our brains to process digital objects as naturally as real-world objects, at the same time other It is suitable for long-term use, but the overall equipment is more complicated and requires the cooperation of multilayer waveguides. The processing of multilayer waveguides is difficult and technically difficult.

Summary of the invention

In order to solve the above technical problems, the purpose of the present invention is to provide a grating array, a 3D display device and a 3D display method, and a 3D light field display solution with good display effect.

According to one aspect of the present invention, a grating array is provided, including: an input grating array and an output grating array arranged on a waveguide substrate,

The input grating array couples incident light into the waveguide matrix and maintains the angle and phase information of the incident light;

The output grating array couples out the light from the waveguide base and restores the angle and phase information of the incident light.

Compared with the prior art, the liquid crystal cell of the present invention has the following beneficial effects: through the input grating array and the output grating array arranged on the waveguide substrate, the output grating array restores the angle and phase information of the incident light, the overall device is light and thin, and does not require multiple layers The waveguides are matched to reduce the processing difficulty.

Further, the input grating array includes a plurality of input gratings, and light rays of different incident angles in the incident light have corresponding input gratings and output gratings;

The input grating is used to couple light with a corresponding incident angle into the waveguide base, and the light propagates in the waveguide base at an angle greater than the total reflection angle to the output grating array, and is coupled out through the corresponding output grating .

The beneficial effect of adopting the above-mentioned further technical solution is that the incident light rays with different incident angles have corresponding input gratings and output gratings, and the incident rays of the light field are divided according to different incident angles, and different angles are selected and coupled through the input gratings. The light is coupled into the waveguide matrix, and the light propagates in the waveguide matrix to the output grating array at an angle greater than the total reflection angle, and then is output from the waveguide matrix through the output grating, which can help collect the light of the light field and integrate this light field. All the information is coupled into the waveguide, and then coupled out to the human eye through the grating array.

Further, the input grating and the output grating include a transparent upper substrate and a lower substrate;

A polymer dispersed liquid crystal material is encapsulated between the upper substrate and the lower substrate, and the polymer dispersed liquid crystal material includes a polymer, an initiator, a liquid crystal, and a surfactant;

The upper substrate and the lower substrate are provided with a transparent conductive film on the side close to the polymer dispersed liquid crystal material. The distribution of the input grating polymer and liquid crystal is adapted to the light of the corresponding incident angle, and will correspond to it. The incident angle of light is coupled into the waveguide matrix.

The beneficial effect of adopting the above-mentioned further technical solution is that the distribution of the input grating polymer and liquid crystal is adapted to the light of the corresponding incident angle, and the liquid crystal-rich area and the polymer-rich area are formed between the upper and lower substrates, and the conductive film is rich in liquid crystal after being energized. The refractive index of the region and the polymer-rich region are different to form a grating structure. The period and grating vector of the grating structure change with the diffraction angle, and the light with the corresponding incident angle is coupled into the waveguide matrix, and the grating is input Each input grating in the array has a different incident angle of light to be coupled. Therefore, the distribution of polymer and liquid crystal of each input grating is different. Similarly, the distribution of polymer and liquid crystal of each output grating is different. When coupling out the light with the corresponding incident angle, the angle and phase information of the incident light is restored. Preferably, each input grating can couple the light within a cone angle into the waveguide, and there is no need for the cooperation of the multilayer waveguide to reduce the cost. .

Further, the liquid crystal is a mixed crystal, the ordinary light refractive index of the mixed crystal is 0.2-0.4 different from the extraordinary refractive index, and the refractive index of the polymer is the same as the extraordinary refractive index of the liquid crystal.

The beneficial effect of adopting the above-mentioned further technical solution is that the birefringence of the liquid crystal is 0.2-0.4, which can increase the refractive index modulation of the entire material system, thereby improving the diffraction efficiency of the grating.

Further, the upper substrate and the lower substrate are encapsulated by a sealing member, the sealing member is a frame glue with a gasket, and the gasket is a polystyrene ball with a diameter of not more than 6 μm, and the frame glue It is a mixed glue composed of ultraviolet glue and heat-sensitive glue.

The beneficial effect of adopting the above-mentioned further technical solution is that the thickness between the upper substrate and the lower substrate can be controlled to be no more than 6μm, the liquid crystal cell can be in a transparent state when not working, energy consumption can be reduced, and the spacer can facilitate the control of the liquid crystal cell thickness of.

According to another aspect of the present invention, a 3D display device is provided, including:

The grating array of any one of the above;

A light source, which provides incident light that can form a three-dimensional light field;

A spatial light modulator located between the light source and the grating array,

The incident light enters the input grating array of the grating array via the spatial light modulator. The function of the spatial light modulator is to modulate the intensity of the incident light with different angles of incidence through a time sequence method to maintain the three-dimensional light field of the incident light. The angle and phase information of light in each direction in the.

Compared with the prior art, the 3D display device of the present invention has the following beneficial effects: the function of the spatial light modulator is to modulate the intensity of light in each direction of the incident light in units of pixels through a time sequence method, and to modulate the different angles of the incident light. The light rays are arranged in time series,

With the help of the spatial light modulator (SLM), the light passes through the SLM to become a light field with a certain angle of view. The grating array can collect the light of the light field, and couple the light of this light field into the waveguide matrix, and then couple it through the grating array Output to human eyes to realize light field display. The input grating array maintains the angle and phase information of the incident light. The waveguide base propagates the light at an angle greater than the total reflection angle. After the grating couples the light to the waveguide base, the light is totally reflected. It is close, the occupied bandwidth is small, and the requirement for the refractive index of the waveguide substrate is small. The waveguide substrate is greater than 1.5 to output a three-dimensional image with a large depth of field and a large field of view. It does not require a relatively expensive waveguide substrate with a large refractive index. To reduce costs, preferably, the spatial light modulator is of a phase type, which can phase-modulate light, which is beneficial to realize a stereo depth effect and output a stereo image with a large depth of field and a large angle of view.

Further, the input gratings included in the input grating array and the output gratings included in the output grating array are both m rows and n columns,

The light emitted by each pixel of the spatial light modulator has an input grating corresponding to its position;

The light emitted by each pixel of the spatial light modulator is coupled into the optical waveguide matrix through an input grating corresponding to its position.

The beneficial effect of adopting the above-mentioned further technical solution is that the input grating and the output grating can be regarded as a liquid crystal cell composed of glass and a transparent conductive film plated on the glass. The liquid crystal cell is filled with polymer-dispersed liquid crystal materials to form a holographic grating. Each pixel emits light at a specific angle of incidence. Each input grating array only needs to couple the light emitted by the corresponding pixel on the spatial light modulator (SLM), which is convenient for the grating array. More accurately restore the angle and phase information of each light in the light field; use the grating array to couple the light in all directions from each point of the SLM image surface to the waveguide matrix, so that the array grating can record the direction information of all the light in the entire light field .

Further, it also includes a control module that controls the spatial light modulator and the power-on sequence of the input grating and output grating so that only one or one column of input gratings in each row of the input grating array is in a power-on state at the same time.

The beneficial effect of adopting the above-mentioned further technical solution is that it can quickly and accurately control that there is only one voltage applied to each row of liquid crystal cells at a time, and at the same time control the corresponding output grating to be applied voltage, which is beneficial to accurately restore each light field. The angle and phase information of the light, there is only one liquid crystal cell working at the same time in each row of liquid crystal cells, so that there will be no crosstalk between the angles, and the angle and phase information of each light in the light field can be restored more accurately. The control module The chip model can choose stm8l.

Further, the frequency of the current applied to the input grating and/or the output grating is 60 mnHZ or 60 nHZ, where m is the number of rows of the input grating, and n is the number of columns of the input grating.

The beneficial effect of adopting the above-mentioned further technical solution is that the larger m and n are, the higher the resolution of the entire 3D display device is, which can help increase the resolution of the 3D display device.

According to another aspect of the present invention, a 3D display method is provided, including the following steps:

Pass the incident light through the time sequence method to modulate the intensity of the light in all directions of the incident light;

Lights of different angles in the incident light are coupled into the optical waveguide matrix through the input grating at the corresponding position according to the modulated time sequence;

The output grating couples the light from the waveguide matrix and maintains the angle and phase information of each light in the incident light, thereby realizing three-dimensional display.

Compared with the prior art, the 3D display method of the present invention has the following beneficial effects: through a time sequence method, the intensity of the incident light rays in each direction is modulated in units of pixels, so that a time difference occurs when light rays of different angles enter the waveguide substrate. At the same time, it only needs to restore the angle and phase information of one angle of light, and does not need to cooperate with the multilayer waveguide, and can output a three-dimensional image with a large depth of field and a large field of view.

Description of the drawings

Figure 1 is a schematic diagram of the structure of the grating array of the present invention;

Figure 2 is a schematic diagram of the structure of the input grating;

Figure 3 is a schematic diagram of the grating array collecting and outputting light within a certain angle;

4 is a schematic diagram of the structure of a 3D display device;

Fig. 5 is a schematic diagram of the spatial light modulator encoding light source light outputting a 3D object;

Figure 6 is a schematic diagram of the correspondence between the pixel points of the spatial light modulator and the input grating;

Fig. 7 is a schematic diagram of collecting and outputting light by a grating array;

Fig. 8 is a schematic diagram of the 3D display device collecting and outputting light.

The numbers shown in the drawings: 100-light source; 200-spatial light modulator; 300-waveguide substrate; 310-input grating array; 311-input grating; 320-output grating array; 321-output grating; 400-human eye; 501-upper substrate; 502-transparent conductive film; 503-frame glue; 504-polymer dispersed liquid crystal material; 1210-light a; 1211-light c; 1220-light b; 1220-light d; 1310-light e; 1320 -Ray f.

detailed description

In order to better understand the technical solutions of the present invention, the present invention will be further described below with reference to the drawings and specific embodiments of the specification.

Example 1:

As shown in Figure 1, a grating array includes: an input grating array and an output grating array arranged on a waveguide substrate;

The input grating array couples incident light into the waveguide matrix and maintains the angle and phase information of the incident light;

The output grating array couples the light from the waveguide base and maintains the angle and phase information of the incident light. The light propagates in the waveguide base at an angle greater than total reflection, and the output grating array couples the light from the waveguide base. Output and restore the angle and phase information of the incident light, which is beneficial to restore each light in the light field when the light enters the human eye.

Further, the input grating array includes a plurality of input gratings, and light beams with different incident angles in the incident light have corresponding input gratings and output gratings; the input grating is used to couple light with corresponding incident angles. Entering the waveguide matrix, the light rays propagate in the waveguide matrix toward the output grating array at an angle greater than the total reflection angle, and are coupled out through the corresponding output grating. Specifically, as shown in FIG. 2, the input grating and output grating , Including a transparent upper substrate and a lower substrate, a polymer dispersed liquid crystal material is encapsulated between the upper substrate and the lower substrate, and the polymer dispersed liquid crystal material includes a polymer, an initiator, a liquid crystal, and a surface active agent; The substrate and the lower substrate are provided with a transparent conductive film on the side close to the polymer dispersed liquid crystal material. The distribution of the input grating polymer and liquid crystal is exposed in the laser interference field, and is adapted to the light of the corresponding incident angle. In this embodiment, the distribution of the polymer and liquid crystal in the input grating is adapted to the light of the corresponding incident angle, and the liquid crystal-rich area and the polymer-rich area are formed between the upper and lower substrates. After the conductive film is energized, the liquid crystal-rich area and the polymer-rich area are formed. The refractive index is different to form a grating structure. The period d of the grating structure and the grating vector k vary with the diffraction angle, and the light with the corresponding incident angle is coupled into the waveguide matrix, and input to each of the grating arrays. The incident angle of the light to be coupled by the input grating is different. Therefore, the distribution of the polymer and liquid crystal of each input grating is different. Similarly, the distribution of the polymer and liquid crystal of each output grating is different and will correspond to it. When the light of the incident angle is coupled out, the angle and phase information of the incident light is restored. The liquid crystal is a mixed crystal, the ordinary light refractive index of the mixed crystal and the extraordinary light refractive index difference is 0.2-0.4, the refractive index of the polymer is the same as the extraordinary light refractive index of the liquid crystal, and the upper substrate and The lower substrate is encapsulated by a sealing member, the sealing member is a frame glue with a gasket, and the gasket is a polystyrene ball with a diameter of not more than 6 μm. In this embodiment, a 5 μm polystyrene ball is selected. The frame glue is a mixed glue composed of ultraviolet glue and heat-sensitive glue, and the polymer dispersed liquid crystal material includes 35 to 45 parts of liquid crystal, 35 to 45 parts of polymer, 8 to 12 parts of initiator, and 8 to 12 parts of surfactant For an example, determine the total weight of the polymer dispersed liquid crystal material 5g, and determine the mass of each component according to the mass ratio of each material: 2g, 0.5g, 2g, 0.5g, and add them to the electronic balance in turn It is made by emulsifying the mixed material in a dark room using an ultrasonic emulsifier for 48 hours in the weighing bottle above. The surfactant is polyoxyethylene sorbitan monooleate, which reduces the surface tension of the material system and reduces the material The driving voltage of the system; the initiator is a laser-sensitive dye that can absorb the energy of the laser and promote the photopolymerization reaction. The choice is determined by the wavelength of the laser. When the excitation light is a green laser with 532 nm, the initiator can be rose bengal; when the excitation light is a red laser with 632.8 nm, the initiator can be methylene blue. After the conductive film is energized, the input grating couples light with a preset angle of incidence into the optical waveguide matrix. As an alternative, the input grating and output grating are formed into a two-dimensional array of rows and columns. Each input grating can combine the light within a cone angle. Coupled into the waveguide, as shown in FIG. 3, a corresponding line of input grating and output grating on the grating array 301 is selected, and the corresponding input grating 311 and output grating 321 are selected. The input grating 311 can couple light within a cone angle (the two limit angle light rays are light a 1210 and light b 1220 respectively), so that the direction of the incident light does not change, and the two rays of light are diffracted into light c 1211 by the input grating 311 The sum light d 1221 propagates in the waveguide 300 at an angle greater than total reflection. When reaching the output grating 321, light e 1310 and light f 1320 are output, and the exit angles of light e 1310 and light f 1320 are symmetrical to the incident angle of light a 1210 and light b 1220 with respect to the normal. At this time, the working gratings are only 311 and 321, so the light propagating in the waveguide will not be diffracted when it reaches the gratings 312 and 322, and still continues to propagate through total reflection, passing through the input grating array and output grating array set on the waveguide substrate , Restore the angle and phase information of the incident light, the overall device is light and thin, does not require the cooperation of multi-layer waveguides, and reduces the difficulty of processing.

As shown in FIG. 4, this embodiment provides a 3D display device using the above-mentioned grating array. In addition to the grating array, it also includes: a light source that provides incident light that can form a three-dimensional light field; located between the light source and the grating array In the spatial light modulator, the incident light enters the input grating array of the grating array via the spatial light modulator, and the function of the spatial light modulator is to modulate the intensity of the incident light at different angles of incidence through a time sequence method to maintain The angle and phase information of the light in each direction in the three-dimensional light field of the incident light enables the light source to reproduce the light field of the three-dimensional object, as shown in Figures 5 and 6, assuming that a three-dimensional object ABCD is behind the SLM. The light emitted by the three vertices A/B/D on the three-dimensional object passes through these three points on the SLM. The three-dimensional information of the three vertices of A/B/D can be viewed on the SLM. With the help of the spatial light modulator (SLM), the light passes through the SLM into a light field with a certain angle of view, and the light in the 3D light field passes through the spatial light. After the modulator modulates the phase of the light, it irradiates the input grating array of the optical waveguide substrate. According to the distance between the SLM and the input grating array liquid crystal cell array and the liquid crystal cell angular bandwidth, the pixel area that each grating can be coupled to can be calculated Range, the grating array can collect the light of the light field, couple the light of this light field into the waveguide matrix, and then couple out the light field to the human eye through the grating array to realize the light field display. In this embodiment, the spatial light modulator (SLM ), preferably, the spatial light modulator is of a phase type, which can phase-modulate light, which is beneficial to realize a stereo depth effect and output a stereo image with a large depth of field and a large angle of view. The light passes through the SLM into a light field with a certain field of view. The grating array can collect the light of the light field, couple the light of this light field into the waveguide matrix, and then couple out the light field to the human eye through the grating array to realize the light field display , Through the input grating array to maintain the angle and phase information of the incident light, the waveguide base propagates the light at an angle greater than the total reflection angle. After the grating couples the light to the waveguide base, the total reflection angle range of the light is close, and the occupied bandwidth is small. The refractive index of the substrate is small, and the waveguide substrate is larger than 1.5 to output a three-dimensional image with a large depth of field and a large field of view. There is no need for a more expensive waveguide substrate with a large refractive index, which can reduce costs. Preferably, spatial light modulation The detector is a phase type, which can phase modulate the light, which is beneficial to realize the stereo depth effect and output a stereo image with a large depth of field and a large angle of view.

As shown in Figure 7, the input gratings included in the input grating array and the output gratings included in the output grating array are all m rows and n columns, each row of the input grating has only one column of input gratings in the energized state at the same time, and each row of the input grating Each pixel has its corresponding input grating 311 (in actual work, the pixel and the input grating may not have a one-to-one correspondence. Each input grating can couple light from a pixel group, and the incident angle of these light is within the value range of b The polymer-dispersed liquid crystal material of the input grating 311 can allow the specific angle information light emitted by the corresponding pixel on the SLM to directly pass through, and the corresponding output grating on the grating array outputs the same light as the specific angle information light Light, the coupled light of each input grating 311 is transmitted to the optical waveguide substrate at different total reflection angles in the waveguide. There is one and only one liquid crystal cell in each row of liquid crystal cells in the working state at the same time. In this embodiment, the control module controls The spatial light modulator and the input grating and output grating energization sequence, the light of different angles in the 3D light field, after SLM modulation, is coupled into the optical waveguide matrix through the input grating 311 of the input grating array, and the light is transmitted to the phase of the output grating array. The corresponding input grating is output from the optical waveguide substrate, and the exit angle of the output light is symmetrical with the incident angle of the incident light with respect to the normal (within the allowable error range), restoring the light in the 3D light field, and each grating can collect a certain cone For the light within the angle, the grating array has m rows and n columns. The larger the m and n, the higher the system resolution. Because the light collected by each liquid crystal cell is transmitted in the waveguide at different total reflection angles, there is only one liquid crystal cell working at the same time Therefore, there will be no crosstalk between the angles, and the angle and phase information of each light in the light field can be restored more accurately.

A 3D display method includes the following steps:

Pass the incident light through the time sequence method, and modulate the intensity of the light in each direction of the incident light in units of pixels;

Lights of different angles in the incident light are coupled into the optical waveguide matrix according to the modulated time sequence;

The output grating array couples the light from the waveguide matrix, and maintains the angle and phase information of each light in the incident light, and maintains the angle and phase information of each light in the incident light, so as to realize three-dimensional display. Specifically, The liquid crystal cell arrays of the input grating array and the output grating array are arranged, and a voltage is applied to one or one column of the input grating 311 in the input grating array, so that only one or one column of the input grating in each row of the input grating array is in the energized state at the same time , The input grating 311 is directly coupled into the optical waveguide substrate, and a voltage is applied to the opposite output grating in the output grating array to restore the angle and phase information of the light directly passing through the input grating 311, and the corresponding 60mnHZ or 60nHZ frequency is applied to the grating array Where m is the number of rows of the input grating, n is the number of columns of the input grating, the control module controls the power-up sequence of the spatial light modulator and the liquid crystal cell of the grating array, so that the human eye thinks the light coupled by each input grating 311 It arrives at the same time, that is, the 3D light field information after SLM modulation can be collected; in this implementation, the light source is a narrowband LED or laser light source, and the material of the waveguide substrate is high refractive index heavy flint glass. It is 0.8-1.5mm. As shown in Figure 8, the grating array has only one set of corresponding input gratings and output gratings working at any time. Taking only one input grating at the same time as an example, the input grating power-on sequence is x1y1→x1y2→... …→x1yn→x2y1→x2y2→……xmy1→xmy2→……xmyn. Correspondingly, the power-on sequence of the output grating is: x1y1→x1y2→……→x1yn→x2y1→x2y2→……xmy1→xmy2→……xmyn. A certain spatial angle of light illuminates a working grating on the input grating array 310, and through it, the corresponding output grating on the output grating array outputs light with the same angle as the incident light, and a frequency above 60 mnHZ is applied to the grating array. In this way, the human eye thinks that the light transmitted by each grating arrives at the same time, that is, the 3D light field information modulated by SLM200 can be collected, and the intensity of the light in each direction of the incident light can be modulated in the unit of pixel by the time sequence method. , So that there is a time difference when light rays of different angles enter the waveguide matrix. At the same time, only the angle phase information of the light rays of one angle needs to be restored, and the multi-layer waveguide is not required to output a stereo image with a large depth of field and a large field of view.

The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solution formed by the specific combination of the above technical features, and should also cover the above technical features without departing from the inventive concept. Or other technical solutions formed by any combination of its equivalent features. For example, the above-mentioned features and the technical features disclosed in this application (but not limited to) with similar functions are mutually replaced to form a technical solution.

Claims (10)

1. A grating array, characterized in that it comprises an input grating array and an output grating array arranged on a waveguide substrate;

   The input grating array couples incident light into the waveguide matrix and maintains the angle and phase information of the incident light;

   The output grating array couples out the light from the waveguide base and restores the angle and phase information of the incident light.
2. The grating array of claim 1, wherein:

   The input grating array includes a plurality of input gratings, and light rays with different incident angles in the incident light have corresponding input gratings and output gratings;

   The input grating is used to couple light with a corresponding incident angle into the waveguide base, and the light propagates in the waveguide base at an angle greater than the total reflection angle to the output grating array, and is coupled out through the corresponding output grating .
3. The grating array according to claim 2, wherein the input grating and output grating comprise a transparent upper substrate and a lower substrate;

   A polymer dispersed liquid crystal material is encapsulated between the upper substrate and the lower substrate, and the polymer dispersed liquid crystal material includes a polymer, an initiator, a liquid crystal, and a surfactant;

   The upper substrate and the lower substrate are provided with a transparent conductive film on the side close to the polymer dispersed liquid crystal material. The distribution of the input grating polymer and liquid crystal is adapted to the light of the corresponding incident angle, and will correspond to it. The incident angle of light is coupled into the waveguide matrix.
4. The grating array of claim 3, wherein the liquid crystal is a mixed crystal, the ordinary light refractive index of the mixed crystal and the extraordinary refractive index difference are 0.2-0.4, and the refractive index of the polymer is The extraordinary light refractive index of liquid crystal is the same.
5. The grating array according to claim 3, wherein the upper substrate and the lower substrate are encapsulated by a sealing member, the sealing member is frame glue with a spacer, and the spacer has a diameter of not more than 6 μm polystyrene balls, the frame glue is a mixed glue composed of ultraviolet glue and heat-sensitive glue.
6. A 3D display device is characterized by comprising:

   The grating array of any one of claims 1-5;

   A light source, which provides incident light that can form a three-dimensional light field;

   A spatial light modulator located between the light source and the grating array,

   The incident light enters the input grating array of the grating array via the spatial light modulator. The function of the spatial light modulator is to modulate the intensity of the incident light with different angles of incidence through a time sequence method to maintain the three-dimensional light field of the incident light. The angle and phase information of light in each direction in the.
7. 7. The 3D display device of claim 6, wherein the input gratings included in the input grating array and the output gratings included in the output grating array are both m rows and n columns,

   The light emitted by each pixel of the spatial light modulator has an input grating corresponding to its position;

   The light emitted by each pixel of the spatial light modulator is coupled into the optical waveguide matrix through an input grating corresponding to its position.
8. 8. The 3D display device according to claim 7, further comprising a control module;

   The control module controls the spatial light modulator and the energization sequence of the input grating and the output grating, so that only one or one column of input gratings in each row of the input grating array is in the energized state at the same time.
9. The 3D display device according to claim 7, wherein the frequency of the current applied to the input grating and/or the output grating is 60 mnHZ or 60 nHZ, where m is the number of rows of the input grating and n is the number of columns of the input grating.
10. A 3D display method, characterized in that it comprises the following steps:

    Pass the incident light through the time sequence method to modulate the intensity of the light in all directions of the incident light;

    Lights of different angles in the incident light are coupled into the optical waveguide matrix through the input grating at the corresponding position according to the modulated time sequence;

    The output grating couples the light from the waveguide matrix and maintains the angle and phase information of each light in the incident light, thereby realizing three-dimensional display.

Images