CN110531528A - Three-dimensional display apparatus - Google Patents

Abstract

The present invention relates to display technologies, in particular to the device for realizing the all-round display of naked eye three-dimensional image.According to the three-dimensional display apparatus of one aspect of the invention, characterized by comprising: light source module group, is configured to issue the first light beam；Spatial light modulator in first direction of beam propagation is configured to that multi-angle of view mixed image information is loaded on first light beam to form the second light beam by amplitude modulation mode；And the phase board in second direction of beam propagation, with diffraction structure, the diffraction structure is configured to the image of the different perspectives in the carried image of the second light beam being projected to corresponding multiple observation positions.

Description

3D display device

technical field

The invention relates to display technology, in particular to a device for realizing multi-view display of naked-eye three-dimensional images.

Background technique

With the improvement of living standards and the rapid development of science and technology, realistic visual experience has become people's pursuit of display screens, and 3D display technology has emerged as the times require. Not only in the traditional display industry, but also in many fields such as multimedia and software development, there is an urgent need for the development and application of 3D display technology. Traditional 3D display technology requires additional auxiliary equipment (such as 3D glasses, etc.) to observe stereoscopic images, which greatly limits people's viewing freedom. Therefore, the development of naked-eye 3D display technology is the general trend.

A hologram is an image that carries amplitude and phase information to truly reproduce three-dimensional information. The characteristic of holographic display is that the hologram can reproduce a three-dimensional virtual image or a three-dimensional real image in space, and each point on the hologram transmits information to all directions in space, and each observation point in space can see the entire image. In other words, the image information converges on the observation point through light field transmission. Therefore, at different observation points in space, the entire image of different viewing angles can be viewed without interfering with each other. However, due to the limitations of holographic recording materials, information volume and technological process for decades, holographic display has not been able to realize dynamic color naked-eye 3D display with wide viewing angle.

Glasses-free 3D display technologies based on the principle of parallax include the visually impaired method and the microcylindrical lens method. In these technologies, a visual barrier or a microcylindrical lens array is arranged on the surface of a liquid crystal display panel to separate images of different viewing angles in spatial angle. Since ghosting and stray light are difficult to eliminate, it is easy to cause visual fatigue when viewing such 3D images. At the same time, due to the influence of stray light, the viewing angle interval is usually set relatively large, resulting in incoherent viewing angles, and it is impossible to achieve a naked-eye 3D display effect without jumping. In addition, existing glasses-free 3D display devices are bulky and difficult to integrate into small devices such as mobile phones.

Contents of the invention

An object of the present invention is to provide a three-dimensional display device, which has the advantages of low manufacturing cost, simple design and compact structure.

A three-dimensional display device according to one aspect of the present invention includes:

a light source module configured to emit a first light beam;

a spatial light modulator located in the propagation direction of the first light beam, configured to load multi-view mixed image information onto the first light beam through amplitude modulation to form a second light beam; and

The phase plate located in the propagating direction of the second light beam has a diffraction structure configured to project images of different viewing angles in the image carried by the second light beam to multiple corresponding observation positions.

Preferably, in the above device, the first light beam is parallel light or divergent light from a point source.

Preferably, in the above device, the spatial light modulator includes a plurality of voxels, each voxel includes a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, and the diffraction structure includes a plurality of nanostructure units, each The nanostructure units are configured to project light beams from a sub-pixel corresponding to the same viewing angle among the plurality of voxels to a plurality of observation positions associated with the sub-pixel.

Preferably, in the above device, the diffractive structure is realized by one of the following structures: one-dimensional nano-grating, two-dimensional nano-grating, spatially multiplexed nano-grating, nano-grating array and diffractive optical element.

Preferably, in the above device, the diffractive structure is realized by a diffractive optical element, and the diffraction efficiency of the diffracted light is minimized when the diffraction order is zero by adjusting the structural depth of the diffractive optical element.

Preferably, in the above device, the light source module includes:

light source;

A backlight panel comprising:

The light guide plate, the light source is located on the side of the light guide plate, the light guide plate includes a first microstructure located on the upper surface, lower surface or inside of the light guide plate, and the first microstructure has first units distributed periodically, causing the light beam emitted by the light source to be scattered to the outside of the light guide plate through the first microstructure; and

The optical film stacked with the light guide plate, which includes a second microstructure located on the surface of the optical film, the second microstructure has second units periodically distributed, scattered to the light guide plate by the first microstructure The external light beam is transformed into the first collimated light beam by the second microstructure.

Preferably, in the above device, the first unit is one of a microprism, a microlens, a free-form surface lens or a pit.

Preferably, in the above device, the second unit is one of a microlens, a Fresnel lens or a film lens.

Preferably, in the above device, the backlight further includes a shading plate, which includes a shading structure corresponding to the first microstructure and the second microstructure to filter out stray light emitted from the second microstructure .

Preferably, in the above device, one of the following positions: between the light guide plate and the optical film, inside the light guide plate, and inside the optical film.

Preferably, in the above device, the light source is an LED line array light source.

Preferably, in the above device, the spatial light modulator is a liquid crystal display unit.

Preferably, in the above device, the light source is a white light source or a three primary color light source, and the device further includes a color filter stacked with the spatial light modulator and phase plate.

Preferably, in the above device, the color filter is arranged between the spatial light modulator and the phase plate.

Description of drawings

FIG. 1 is a schematic diagram of a three-dimensional display device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a backlight panel applicable to the device shown in FIG. 1 .

FIG. 3 is a schematic diagram of another backlight panel applicable to the device shown in FIG. 1 .

4a-4d are schematic diagrams of a single nanostructure unit applicable to the phase plate in the embodiment shown in FIG. 1 .

5a-5c are schematic diagrams showing the effect of the sub-pixel viewpoint (array) of the phase plate composed of the nanostructure units shown in FIGS. 4a-4d.

FIG. 6 is a schematic diagram showing a multi-view image display structure for enlarging the vertical viewing angle.

FIG. 7 is a schematic diagram showing a multi-view image display structure for enlarging the lateral viewing angle.

FIG. 8 is a schematic diagram showing another multi-view image display structure for enlarging the lateral viewing angle.

FIG. 9 is a schematic diagram showing a surround-view display structure realized by enlarging the vertical and horizontal viewing angles simultaneously.

FIG. 10 is a schematic diagram showing another surround-view display structure realized by enlarging the vertical and horizontal viewing angles simultaneously.

Detailed ways

The purpose of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a three-dimensional display device according to an embodiment of the present invention.

The device 10 shown in FIG. 1 includes a light source module 110 , a spatial light modulator 120 and a phase plate 130 . Referring to FIG. 1, the spatial light modulator 120 is arranged in the propagation direction of the light beam B1 (hereinafter also referred to as the first light beam) emitted by the light source module 110, and it loads the multi-view mixed image information on the first light beam B1 by way of amplitude modulation. A second light beam B2 is formed. The phase plate 130 is arranged on the propagating direction of the second light beam B2, and it uses the nanostructure unit to project the image of each viewing angle in the image carried by the second light beam B2 to a plurality of corresponding observation positions (such as surrounding the display desktop curve ( Or curved surface) arranged different observation areas), so as to obtain the effect of multi-view display of naked-eye 3D.

As will be seen below, the nanostructure unit of the phase plate can convert the image of the same viewing angle to a visual window composed of multiple viewpoints or multiple viewpoint arrays, thereby expanding the display information throughput without increasing the display information throughput. The field of view is improved to achieve the effect of peripheral vision display.

FIG. 2 is a schematic diagram of a light source module applicable to the device shown in FIG. 1 according to another embodiment of the present invention.

The light source module 110 shown in FIG. 2 includes a light source 111 and a backlight plate 112 . The backlight 112 may be, for example, a directional backlight, which includes a light guide plate 1121 and an optical film 1122 . Exemplarily, the optical film 1122 may be a micro-nano optical film. As shown in FIG. 2 , a first microstructure 1121A having periodically distributed first units (shown as pits in the figure) is formed on the upper surface of the light guide plate 1121 . The light source 111 is located at the side of the light guide plate 1121 , and the light beam emitted by it enters the light guide plate 1121 and is scattered to the outside of the light guide plate 1121 through the first microstructure 1121A.

Although the first microstructure 1121A shown in FIG. 2 is formed on the upper surface of the light guide plate 1121 , it is also formed on the lower surface or inside of the light guide plate 1121 . Preferably, the size of the first microstructure is between 100 nm-1 mm. In the backlight panel 112 shown in FIG. 2 , the first unit is exemplarily shown in the form of a pit, but it can also be other forms of optical elements, such as including but not limited to microprisms, microlenses, and free-form surface lenses. Wait.

Continuing to refer to FIG. 2 , the optical film 1122 is located under the light guide plate 1121 . The optical film 1122 can be stacked with the light guide plate 1121 or maintain a certain air gap with the light guide plate 1121 (when the refractive index of the optical film is close to or higher than that of the light guide plate). In addition, a layer of low refractive index may also be inserted between the light guide plate 1121 and the optical film 1122 to avoid a total reflection condition in the light guide plate. As shown in FIG. 2 , a second microstructure 1122A with periodically distributed second units is formed on the surface of the optical film 1122. The second microstructure 1122A is structurally matched with the first microstructure 1121A, and the function is to self-conduct The divergent light beam of the light plate 1121 is transformed into a collimated light beam B1 that emerges in one or more directions. Preferably, the second micro-nano structure 1122A adopts a configuration such as a microlens array, a Fresnel lens array, a thin-film lens array, and a binary structured light array. The lens units of the microlens array, Fresnel lens array or film lens array can be optimally designed according to the relative position of the microstructures in the light guide plate to obtain better collimating or converging effects. For example, the diameter of each unit or microlens in the optical film 112 can be designed to be larger than the unit or pit structure of the light guide plate 1121 .

In this embodiment, plastic or glass can be selected as the material of the light guide plate or the micro-lens, and its refractive index is between 1-2.5. Preferably plastic can be used to make the product lighter and lower the cost. In addition, the light guide plate 1121 may be composed of one material or multiple materials having different refractive indices. The light guide plate and the optical film can be manufactured by grayscale photolithography, laser etching, etc., and can be replicated in batches by nanoimprinting.

Preferably, a shading plate may be provided in the backlight plate 112 to filter out unwanted stray light. For example, in the backlight plate shown in FIG. 3 , it may be considered to provide a light shielding plate 1123 between the light guide plate and the optical film. The shading plate includes a shading plate corresponding to the first microstructure 1121A and the second microstructure 1122A, so as to filter the stray light emitted from the second microstructure. The shading plate can be a single-layer or multi-layer independent structure, and can be integrated with any one or more of the light guide plate, optical film, spatial light modulator and Fresnel lens group to form a functional composite optical device.

It should be pointed out that in this specification, collimated light beams, parallel light beams, directional light beams and converging light beams propagating in one direction refer to outgoing light rays whose divergence angle half maximum width is within 30°. Preferably, the half-maximum width of the divergence angle of the outgoing light is within a range of 10°.

In the embodiment shown in FIG. 1 , the spatial light modulator 120 is used for amplitude modulation, that is, for loading multi-view mixed image information. The spatial light modulator may include, for example, a display panel, a driving circuit, a control system, software control, and the like. According to the needs of specific application fields, the spatial light modulator can realize monochrome or color display. Preferably, the spatial light modulator 120 may be a liquid crystal display unit. The spatial light modulator 120 may include a plurality of voxels or amplitude modulated pixels, each voxel includes a plurality of sub-pixels, and each sub-pixel corresponds to a different viewing angle.

In the prior art, the image from each sub-pixel of the spatial light modulator is projected by the phase plate to a corresponding single viewing angle or viewing position, but as will be seen from the following description, in the present invention, the phase plate spatially The image of each sub-pixel of the light modulator is projected to a corresponding viewing angle array or a group of viewing positions, thereby widening the viewing angle.

In order to obtain a set of observation positions, in this embodiment, the phase plate 130 has a diffractive structure, and the diffractive structure includes a plurality of voxels. Further, each voxel of the phase plate 130 contains a plurality of nanostructure units, and each nanostructure unit is matched and aligned with the viewing angle image pixel of the spatial light modulator, that is to say, the plurality of voxels from the spatial light modulator 120 The light beams of the sub-pixels corresponding to the same viewing angle in the pixel are projected to a group of observation positions associated with the sub-pixels. Preferably, the diffractive structure can be realized with various structures, including but not limited to one-dimensional nano-grating, two-dimensional nano-grating, spatially multiplexed nano-grating, nano-grating array and diffractive optical element (or secondary optical element), etc.

4a-4d are schematic diagrams of a single nanostructure unit applicable to the phase plate in the embodiment shown in FIG. 1 .

Taking FIG. 4a as an example, the nanostructure unit 131 is in the form of a pixel unit, which is divided into nine grating regions 1a-1i with different periods and/or orientation angles. When the light from a sub-pixel of the spatial light modulator 120 When arriving, different grating areas will deflect the light to different observation positions, thereby realizing the projection of the light beam of the same viewing angle to multiple observation positions, thereby expanding the field of view.

The period and orientation angle of the grating area can be determined according to the following grating equation:

tanφ ₁ = sinφ/(cosφ-nsinθ(Λ/λ)) (1)

sin ² (θ ₁ )＝(λ/Λ) ² +(nsinθ) ² -2nsinθcosφ(λ/Λ) (2)

Among them, _θ1 and φ1 represent the diffraction angle _of the diffracted light (the angle between the diffracted light and the negative direction of the z-axis) and azimuth angle (the angle between the diffracted light and the positive direction of the y-axis), respectively, and θ and λ represent the incident light source angle (the angle between the incident light and the negative direction of the z-axis) and wavelength, Λ and φ respectively represent the period and orientation angle of the nano-diffraction grating (the angle between the groove direction and the positive direction of the x-axis), and n represents the refraction of light waves in the medium Rate.

Therefore, when the incident light wavelength, incident angle, diffracted light diffraction angle and diffraction azimuth angle are determined, the required grating period and orientation angle can be calculated using the above formula.

As another example, the nanostructure unit 131 shown in FIG. 4b adopts the form of grating spatial multiplexing, which is formed by stacking nine gratings with different periods and/or orientation angles. When one of the gratings from the spatial light modulator 120 When the sub-pixel light arrives, different gratings also deflect the light to different observation positions, thereby realizing the projection of the light beam of the same viewing angle to multiple observation positions, thereby expanding the field of view.

The nanostructure units shown in Figures 4c and 4d are two-step diffractive optical elements and multi-step diffractive optical elements respectively, which can also deflect light from one viewing angle to different observation positions.

5a-5c are schematic diagrams showing the effect of the sub-pixel viewpoint (array) of the phase plate composed of the nanostructure units shown in FIGS. 4a-4d. The light incident on a single nanostructure unit undergoes wavefront transformation to form multiple visible regions, which can be strips as shown in Figure 5a, rings as shown in Figure 5b or crosses as shown in Figure 5c shape. Obviously, this expands the horizontal and/or vertical viewing range, so that the observer can observe information images of the same viewing angle when moving up, down, left, and right.

In the present invention, the term "peripheral viewing display" can be understood as a display implemented by expanding the viewing angle in both lateral and longitudinal directions. In the following, the two aspects of expanding the horizontal field of view and extending the vertical field of view are respectively described.

FIG. 6 is a schematic diagram showing a multi-view image display structure for enlarging the vertical viewing angle.

Without loss of generality, FIG. 6 takes a display device with four viewing angles as an example for illustration. In FIG. 6 , each voxel on the phase plate 130 contains 4 sub-pixels or nanostructure units. Exemplarily, each nanostructure unit in FIG. 6 contains 3 nano-gratings. By controlling the orientation angle and/or period of the nano-gratings, 3 visible regions can be formed in the longitudinal direction as shown in FIG. 6 . Each voxel on the phase plate 130 is matched and aligned with the voxel of the spatial light modulator 120, so that three information images of the same viewing angle can be presented in three longitudinally arranged viewable areas, thus without increasing the space In the case that the light modulator needs to refresh the displayed information, the effect of expanding the longitudinal field of view is achieved.

FIG. 7 is a schematic diagram showing a multi-view image display structure for enlarging the lateral viewing angle.

Similarly, FIG. 7 also takes a display device with four viewing angles as an example for illustration. In FIG. 7 , each voxel on the phase plate 130 corresponds to one voxel of the spatial light modulator 120 and contains 4 nanostructure units. Each nanostructure unit is formed by stacking multiple nanograting structures (for example, as shown in FIG. 4b ). By controlling the orientation angle and period of these spatially multiplexed nano-grating structures, multiple visible regions distributed at certain intervals can be formed along the lateral direction. Each voxel on the phase plate 130 is matched and aligned with the voxel of the spatial light modulator 120, so that multiple information images of the same viewing angle can be presented in the visible area arranged at a certain interval, thus without increasing the spatial light When the modulator needs to refresh the display information, the effect of expanding the viewing angle is achieved.

FIG. 8 is a schematic diagram showing another multi-view image display structure for enlarging the lateral viewing angle.

Similarly, FIG. 8 also uses a display device with four viewing angles as an example for illustration. In FIG. 8, each voxel on the phase plate 130 corresponds to one voxel of the spatial light modulator 120 and contains 4 nanostructure units (eg, nanostructure units having the form shown in FIGS. 4c and 4d). By designing the structure of the diffractive optical element according to the theory of light wave diffraction, a plurality of visible (strip-shaped) areas distributed at certain intervals can be formed along the lateral direction. Each voxel on the phase plate 130 is matched and aligned with the voxel of the spatial light modulator 120 , so that multiple information images of the same viewing angle can be presented in a visible (strip) area arranged at a certain interval. At the same time, the nanostructure units of different sub-pixels corresponding to the information images of different viewing angles are distributed sequentially in the horizontal direction, and together form the circularly distributed visible point (line) array regions 1-4, thus without increasing the required cost of the spatial light modulator. In the case of refreshing the display information, the effect of expanding the viewing angle is achieved.

The diffraction efficiency η of a diffractive optical element or a binary optical element can be determined by the following formula:

Among them, N is the number of steps of the binary optical element, and m is the diffraction order.

In an ordinary diffraction grating, the zero-order diffracted light occupies most of the energy, while the useful +1 or -1-order diffracted light occupies a limited proportion of energy, which greatly affects the quality and effect of the display. In this embodiment, preferably, by adjusting the structural depth of the diffractive optical element on the phase plate, the diffraction efficiency of the diffracted light at the diffraction order of m=0 can be minimized (for example, equal to 0), that is to say, the zero order The diffracted light is completely eliminated, so that the energy is mainly concentrated on the +1 or -1 order diffracted light, which greatly improves the utilization rate of light energy.

FIG. 9 is a schematic diagram showing a surround-view display structure realized by enlarging the vertical and horizontal viewing angles simultaneously. Without loss of generality, FIG. 9 illustrates with a peripheral view display structure of 3 voxels. In FIG. 9 , each voxel on the phase plate 130 contains 4 sub-pixels or nanostructure units. Exemplarily, each nanostructure unit in Fig. 6 may be in the form of a pixel unit as shown in Fig. 4a, or in the form of grating spatial multiplexing as shown in Fig. 4b, or in the form of a grating as shown in Fig. 4c and 4d The form of the diffractive optical element shown. By controlling the orientation angle and/or period of the nano-grating or designing the structure of the diffractive optical element, the information image of the same viewing angle can be presented in multiple visible areas arranged in the vertical and horizontal directions at the same time, so that there is no need to increase the spatial light modulator. In the case of needing to refresh the displayed information, it can achieve the display effect of peripheral vision.

FIG. 10 is a schematic diagram showing another surround-view display structure realized by enlarging the vertical and horizontal viewing angles simultaneously. Compared with the display structure shown in FIG. 9 , the difference mainly lies in the vertical and horizontal arrangement of multiple visible areas of the image information of the same viewing angle.

It should be pointed out that the embodiments described above are also applicable to color display applications. To this end, a three-color (or white) LED light bar can be used as a light source, and a color filter is provided in the device for realizing naked-eye three-dimensional image display. The color filter can be stacked with the phase plate and the spatial light modulator, and the stacking order can be changed. For example, the color filter can be arranged between the backlight plate and the spatial light modulator, between the spatial light modulator and the phase plate, or behind the phase plate. Preferably, a color filter is arranged between the spatial light modulator and the phase plate. The light beam emitted from the backlight is provided by the spatial light modulator with the image information of the multi-view naked-eye 3D display, and then the wavelength information is loaded by the color filter, and finally the phase modulation is realized by the phase plate, so that in the front viewable area of the phase plate Multiple converging light fields are formed to achieve the effect of naked-eye 3D display.

Compared with the prior art, the device for realizing naked-eye three-dimensional image display of the present invention has many advantages. For example, a larger viewing angle can be provided so that clear naked-eye 3D or 2D images can be viewed in any direction of the plane without visual fatigue. As another example, since the diffractive optical element can eliminate the 0th-order diffraction and concentrate the energy on the required diffraction order, the diffraction efficiency is obviously improved. As another example, the backlight (including LED light source, light guide plate and optical film) and Fresnel lens can be industrially produced by using the existing nanoimprint technology. The production process is mature, the product consistency is easy to ensure, and it is conducive to reducing costs. In addition, each unit of the backlight panel can be designed in a modular manner, and each module achieves relatively independent optical characteristics (such as illumination uniformity, outgoing light divergence angle, etc.), which decouples various parameters, simplifies the design process and makes the optical parameters adjustment is easier. Furthermore, the device for displaying naked-eye three-dimensional images of the present invention is composed of multiple thin-film optical devices stacked, has good compatibility with existing liquid crystal screen structures, and has wide application fields.

The foregoing describes the principles and preferred embodiments of the invention. However, the invention should not be construed as limited to the particular embodiments discussed. The preferred embodiments described above should be considered as illustrative rather than restrictive, and it should be understood that those skilled in the art may, without departing from the scope of the present invention as defined by the following claims, Variations were made in these examples.

Claims (14)

1. A three-dimensional display device, characterized in that it comprises: a light source module configured to emit a first light beam; a spatial light modulator located in the propagation direction of the first light beam, configured to load multi-view mixed image information onto the first light beam through amplitude modulation to form a second light beam; and The phase plate located in the propagating direction of the second light beam has a diffraction structure configured to project images of different viewing angles in the image carried by the second light beam to multiple corresponding observation positions. 2. The device according to claim 1, wherein the first light beam is parallel light or divergent light from a point source. 3. The device of claim 1, wherein the spatial light modulator comprises a plurality of voxels, each voxel comprises a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, and the diffractive structure comprises a plurality of The nanostructure unit, each nanostructure unit is configured to project the light beams from the sub-pixel corresponding to the same viewing angle in the plurality of voxels to the plurality of observation positions associated with the sub-pixel. 4. The device according to claim 3, wherein the diffractive structure is realized by one of the following structures: one-dimensional nano-grating, two-dimensional nano-grating, spatially multiplexed nano-grating, nano-grating array and diffractive optical element. 5. The device according to claim 4, wherein the diffractive structure is realized by a diffractive optical element, and the diffraction efficiency of the diffracted light is minimized when the diffraction order is zero by adjusting the structural depth of the diffractive optical element. 6. The device according to claim 1, wherein the light source module comprises: light source; A backlight panel comprising: The light guide plate, the light source is located on the side of the light guide plate, the light guide plate includes a first microstructure located on the upper surface, lower surface or inside of the light guide plate, and the first microstructure has first units distributed periodically, causing the light beam emitted by the light source to be scattered to the outside of the light guide plate through the first microstructure; and The optical film stacked with the light guide plate, which includes a second microstructure located on the surface of the optical film, the second microstructure has second units periodically distributed, scattered to the light guide plate by the first microstructure The external light beam is transformed into the first collimated light beam by the second microstructure. 7. The device according to claim 6, wherein the first unit is one of a microprism, a microlens, a free-form surface lens, or a pit. 8. The device of claim 6, wherein the second unit is one of a microlens, a Fresnel lens, or a thin film lens. 9. The device according to claim 6, wherein the backlight further comprises a light-shielding plate comprising a light-shielding structure corresponding to the first microstructure and the second microstructure to filter out light from the second microstructure. Stray light emitted by the structure. 10. The device of claim 9, one of the following locations: between the light guide plate and the optical film, inside the light guide plate, and inside the optical film. 11. The apparatus of claim 9, wherein the light source is an LED line array light source. 12. The device of claim 1, wherein the spatial light modulator is a liquid crystal display unit. 13. The device according to claim 1, wherein the light source is a white light source or a three primary color light source, and the device further comprises a color filter stacked together with the spatial light modulator and phase plate. 14. The device of claim 13, wherein the color filter is disposed between the spatial light modulator and the phase plate.