CN211698580U - Bragg period scanning type holographic imager - Google Patents

Abstract

The utility model relates to a 3D formation of image field discloses a Bragg periodic scanning formula holographic imaging ware, including setting up imaging element, the imaging mirror group and the focal depth scanning mechanism in holographic imaging ware inside respectively, imaging element is used for providing a plurality of non-coincident or the equivalent image planes that are parallel to each other, and the imaging mirror group is used for optical imaging and is formed with a plurality of two-dimentional tangent planes; the focal depth scanning mechanism is respectively connected with the driving imaging element and/or the imaging lens group and is used for controlling the spatial position change of the imaging element and/or the imaging lens group to realize the volume scanning of the two-dimensional section. The utility model discloses an introduce the 3D formation of image/projection display function of realization super high resolution and ultrafast frame frequency that many focal planes and Bragg period scanning mode can be stable.

Description

Bragg period scanning type holographic imager

Technical Field

The utility model belongs to the technical field of 3D formation of image and specifically relates to a Bragg periodic scanning formula holographic imager is related to.

Background

The 3D display technology can provide additional depth information on the basis of the conventional two-dimensional display, and thus is considered to be a development direction of the next generation display technology. However, at present, no effective scheme for realizing 3D display exists, and most of the successful commercial cases are pseudo-3D technologies based on stereo image pairs, and cannot provide a true 3D picture with depth information for users. For example, in a 3D movie of a movie theater, the principle is to use a projector to project two-dimensional left and right eye image pairs on a screen, and to wear selective filter eyes, so that the two eyes receive different images, thereby giving people an illusion of seeing a 3D image, but the projected image is only a 2D image. Long-term viewing can also cause eye discomfort.

The true 3D effect can be realized by using a volume scanning imaging mode, and the method is a very potential 3D solution. However, the volume scanning imaging 3D usually needs a high-speed rotating/moving screen, the system has a large potential safety hazard, poor stability, very limited display space, and is unable to be directly touched for interaction, and the display image path is transparent and unable to express correct shielding relationship.

Patents entitled CN106773469B, CN 207114903U and CN 206431409U disclose a scheme that can implement true 3D display. The key component of the three-dimensional display device is a three-dimensional display module, and the three-dimensional display module can realize real 3D picture reproduction through depth-of-field scanning. The working principle is that one focal plane is scanned back and forth in the depth direction (depth of field scanning) to form a continuous 3D picture. Although the mode can realize the projection of the 3D picture, the requirement on the movement speed of a mechanical structural part of a display system is extremely high depending on the scanning imaging of a single focal plane, the reliability of the system cannot be ensured, the refreshing speed of the picture and the overall brightness of the picture cannot be optimized, meanwhile, an operation and control system is extremely complex, stable picture display is difficult to realize, and the manufacturing cost is extremely high. An all-solid-state holographic projector, application No. 202010029144.5, discloses the effect of achieving an all-solid-state holographic display by providing multiple discrete focal planes within a projector. However, the 3D images formed in this way are not continuous, but one slice image in real space cannot completely realize continuous 3D images, and the visual performance of the 3D image with a large depth of field variation cannot meet the psychological expectation of the user.

In order to realize 3D display, in addition to a device capable of displaying 3D pictures, a device capable of realizing 3D video recording is required, and a light path for 3D display according to a light path reversible principle can be used, and in turn, 3D video shooting can also be realized.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in: aiming at the defects of the prior art, the Bragg period scanning type holographic imager is provided, the small-amplitude (Bragg period scanning) scanning of a two-dimensional section is realized by introducing a focal depth scanning mechanism, the continuous full scene reproduction can be realized, compared with the traditional volume scanning 3D mode, the reliability is guaranteed, the refreshing rate can be improved by more than one order of magnitude, and the watching experience of a user is greatly improved.

In order to solve the above technical problem, the utility model provides a Bragg period scanning formula holographic imager, including setting up respectively in holographic imager inside:

the imaging element is used for providing a plurality of non-coincident or mutually parallel equivalent image planes, and the number of the equivalent image planes is n;

the imaging lens group corresponds to the equivalent image surface in position, is used for optical imaging and is provided with a plurality of two-dimensional sections; and

and the focal depth scanning mechanism is respectively connected with the imaging element and/or the imaging lens group and is used for controlling the spatial position change of the imaging element and/or the imaging lens group so as to realize the volume scanning of the two-dimensional section.

Further, the scanning frequency or equivalent frequency of the focal depth scanning mechanism is greater than

Furthermore, the focal depth scanning mechanism realizes the volume scanning of the two-dimensional section by changing the space position between the equivalent image plane and the imaging lens group and/or the effective focal length of the imaging lens group.

Further, the focal depth scanning mechanism realizes the volume scanning of the two-dimensional section by changing the relative position and/or the overall position of the optical elements in the imaging lens group.

Further, the imaging lens group at least comprises a liquid zoom lens or a flexible zoom lens.

Further, the focal depth scanning mechanism controls the amplitude of the volume scanning along the focal depth direction to be L₁And the distribution depth of the equivalent image planes along the depth of focus direction is L₂Mm, satisfy L₁＜L₂。

Further, the mass Mg of the imaging element and the number n of equivalent image planes satisfy:

further, the imaging element is a projection display element or a photographing photosensitive element.

Furthermore, a plurality of projection display chips and shooting photosensitive chips are arranged in the imaging element so as to realize the double functions of projection and shooting.

Compared with the prior art, the utility model has the advantages of:

1. the utility model can realize the complete continuous 3D scene reappearance, and is the holographic display in the true sense;

2. the utility model discloses a only need little range (Bragg periodic scanning) scanning in the course of the work, just can realize that the continuous whole scene reappears, compare with the body scanning 3D mode in the past, the reliability can be ensured, can also promote more than an order of magnitude to the refresh rate simultaneously, greatly improve the user and watch experience; the method has no potential safety hazard, can realize the touch operation of the 3D picture, and can correctly express the shielding relation;

3. when the utility model is applied, the eyes need to dynamically adjust the focal depth as the real things are watched, but not the fixed focal depth of the common 2D display picture, so that the visual fatigue can not be caused, and the visual protection is facilitated;

4. the utility model discloses can realize the projection simultaneously and shoot the function, output picture information and real-time reception external image information when making things convenient for practical application, can discern user interaction, expression information when showing if.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Figure 1 is an imager in which an imaging element 1 is a projection display element and a system diagram of embodiment 1,

fig. 2 on the basis of fig. 1, an imaging element 1 provides a schematic view of an equivalent image plane 2 including both a physical real image plane and a virtual image plane obtained by optical transformation,

FIG. 3 is a schematic diagram of the system of the imager of the present invention replacing the projection display element with the photographing photosensitive element based on FIG. 1,

fig. 4 is a schematic diagram of the equivalent image plane 2 including a physical real image plane and a virtual image plane obtained through optical transformation on the basis of fig. 3, and mainly shows the difference between the equivalent image plane 2 and the two-dimensional section 4 in fig. 3,

figure 5 is a schematic diagram of the system of example 2,

figure 6 is a schematic diagram of the system of example 3,

FIG. 7 is a diagram illustrating a state of one vibration cycle of the equivalent image plane 2

FIG. 8 is a schematic diagram of the mechanical zooming of the imaging lens assembly 3,

FIG. 9 is a schematic view of the zooming principle of the imaging lens assembly 3 using a flexible zoom lens,

the reference numbers are as follows:

the imaging device comprises an imaging element 1, an equivalent image surface 2, an imaging lens group 3, a two-dimensional section 4 and a focal depth scanning mechanism 5.

Detailed Description

In order to make the technical solution of the present invention better understood, the present invention is described in detail below with reference to the accompanying drawings, and the description of the present invention is only exemplary and explanatory, and should not be construed as limiting the scope of the present invention.

Referring to fig. 1 to 9, the present invention provides a bragg period scanning type holographic imager, which includes an imaging element 1, an imaging lens group 3 and a focal depth scanning mechanism 5 respectively disposed inside the holographic imager;

the imaging element 1 is configured to provide a plurality of non-coincident or mutually parallel equivalent image planes 2, where the number of the equivalent image planes 2 is n, and these equivalent image planes 2 may be physical real image planes, or virtual image planes or real image planes obtained through optical conversion, and the like, and the specific implementation manner is a detailed implementation scheme in an all-solid-state holographic projector with application number 202010029144.5, which is not described herein any more;

the position of the imaging lens group 3 corresponds to the equivalent image surface 2, and the imaging lens group is used for optical imaging and is provided with a plurality of two-dimensional sections 4;

the focal depth scanning mechanism 5 is respectively connected with the imaging element 1 and/or the imaging lens group 3 and is used for controlling the spatial position change of the imaging element 1 and/or the imaging lens group 3 to realize the volume scanning of the two-dimensional section 4, and preferably performs reciprocating motion back and forth to realize the volume scanning;

this kind of volume scanning is equivalent to the depth of field scanning of 3D picture, can scan out an imaging space, forms the array of denser two-dimensional tangent plane 4 or continuous 3D picture in this space, the utility model discloses preferred adoption is controlled each part and is carried out periodic position change and realize periodic volume scanning.

Each equivalent image surface 2 and each two-dimensional section 4 are full of pixel arrays (two-dimensional), a plurality of equivalent image surfaces 2 and two-dimensional sections 4 can form three-dimensional pixel arrays respectively, and the unique multi-section image surface structure is very similar to a three-dimensional Bragg lattice structure. The structure is characterized in that a space far larger than a Bragg unit cell can be swept through only by integrally moving a Bragg period, so that the scanning frequency can be greatly improved. Because the Bragg period length is very small, the moving range of the scanning mechanism is very small, and the stability and the reliability of the scanning mechanism are greatly improved compared with those of a conventional large-scale scanning system.

The imaging element 1 may be a projection display element or a photographing photosensitive element;

as shown in fig. 1 and 2, when the projection display element is used as the imaging element 1, the scanning imager of the present invention is used as a holographic projector:

the light of the projection display element forms a plurality of two-dimensional sections 4 in the space after being optically converted by the imaging mirror group 3, and forms a two-dimensional section array, which is equivalent to the display effect that the imaging mirror group 3 directly projects a plurality of equivalent image surfaces 2 optically conjugated with the two-dimensional section array, the spatial position change of the projection display element and/or the imaging mirror group 3 is controlled by the focal depth scanning mechanism 5, preferably, the periodic change is selected, so that the relative position or the whole position between the equivalent image surfaces 2 and the imaging mirror group 3 is periodically changed, the array of the two-dimensional sections 4 in the space is vibrated along the focal depth direction to carry out the body scanning, the previous multilayer section type and discontinuous three-dimensional display effect forms a denser array of the two-dimensional sections 4 or a continuous 3D picture after being scanned, and the continuous 3D display effect is realized;

since optical conjugation exists between the two-dimensional section 4 and the equivalent image planes 2, when the array of the two-dimensional section 4 is subjected to volume scanning, the plurality of equivalent image planes 2 are also subjected to volume scanning at the same time;

as shown in fig. 3 and 4, when the photographing photosensitive element is used as the imaging element 1, the scanning imager of the present invention is used as a hologram:

similar to the projection process, by the principle of reversible optical path, the light of the external scenery is optically converted by the imaging lens group 3, then a plurality of real-image two-dimensional sections 4 are generated on the shooting photosensitive element and recorded, and the light equivalent to the external scenery is optically imaged by the imaging lens group 3 and then directly generates the effect of a plurality of equivalent image surfaces 2 optically conjugated with the external scenery;

this point is very similar with ordinary camera theory of operation, and what the difference is that ordinary camera only has a sensitization chip, can only record the scenery information of the optics conjugation department that corresponds with it, and the utility model discloses a contain a plurality of sensitization chips in the shooting photosensitive element, consequently can a plurality of images of simultaneous recording, and every like the scenery that corresponds different depth of field respectively, reach the shooting record of similar section 3D formula. The focal depth scanning mechanism 5 controls the spatial position change, preferably the periodic change, of the shooting photosensitive element and/or the imaging lens group 3, so that the relative position or the whole position between the equivalent image plane 2 and the imaging lens group 3 is periodically changed, and the corresponding depth of field space optically conjugated with the photosensitive chip or the equivalent image plane 2 is periodically scanned, so that the information of different depths of the scenery is respectively recorded, thereby recording complete and continuous 3D scenes and realizing the aim of 3D shooting, according to the reversible optical path, the periodic scanning process is carried out on the depth of field space optically conjugated with the shooting photosensitive chip or the equivalent image surface 2, the corresponding periodic scanning is carried out on the equivalent image surface 2, the equivalent image plane 2 and the two-dimensional tangent plane 4 are in an equivalent relationship, so that the scanning of the equivalent image plane 2 can be equivalent to the scanning of the two-dimensional tangent plane 4;

the utility model discloses it realizes periodic body scanning to preferably adopt each part of control to carry out periodic position change. For example, the imaging element 1 is mechanically controlled to periodically scan back and forth in the space, that is, a continuous space can be scanned in the space, in practical application, the imaging element can scan back and forth at a fixed frequency, and different frequencies can be used for scanning according to the display content;

or the focal depth scanning mechanism 5 controls the effective focal length of the imaging lens group 3 to periodically change, and can also realize the reciprocating scanning of the two-dimensional section 4, the periodic change of the effective focal length of the imaging lens group 3 can be realized by changing the relative position and/or the overall position of the optical elements in the imaging lens group 3 (mechanical zooming mode), and can also be realized by arranging a liquid zoom lens and/or a flexible zoom lens with zooming function in the imaging lens group 3;

in addition, the display effect can be further improved by a three-dimensional scanning mode besides the pure one-dimensional depth-of-field scanning. For example, the scanning parallel to the equivalent image plane 2 is added, so that the lateral resolution can be further increased, and the image quality is more fine.

The design of the specific scanning mechanism belongs to the common knowledge in the field, and can be designed according to the actual use scene, which is not described herein.

The following uses the imaging element 1 as a projection display element, and the number n of equivalent image planes 2 is 3, the holographic imager of the present invention is described as an embodiment, and the present invention is further described as follows:

example 1

As shown in fig. 1, the bragg period scanning type holographic imager includes a projection display element, an imaging lens group 3 and a focal depth scanning mechanism 5, which are respectively disposed inside the bragg period scanning holographic imager, the focal depth scanning mechanism 5 is connected to the projection display element and controls the projection display element to periodically reciprocate back and forth in the depth of field direction, so that the relative position between the equivalent image plane 2 and the imaging lens group 3 also periodically changes, and a two-dimensional section 4 optically conjugated to the equivalent image plane 2 vibrates in the depth of focus direction to periodically reciprocate back and forth, thereby realizing a continuous 3D display effect.

Example 2

As shown in fig. 5, the bragg period scanning type holographic imager includes a projection display element, an imaging lens group 3 and a focal depth scanning mechanism 5, which are respectively disposed inside, the focal depth scanning mechanism 5 is connected to the imaging lens group 3 and controls the imaging lens group 3 to periodically reciprocate back and forth in the depth of field direction, so that the relative position between the equivalent image plane 2 and the imaging lens group 3 periodically changes, and a two-dimensional section 4 optically conjugated to the equivalent image plane 2 vibrates in the depth of focus direction to periodically reciprocate back and forth, thereby realizing a continuous 3D display effect.

Example 3

As shown in fig. 6, the bragg period scanning type holographic imager includes a projection display element, an imaging lens group 3 and a focal depth scanning mechanism 5, which are respectively disposed inside, the focal depth scanning mechanism 5 is respectively connected to the projection display element and the imaging lens group 3 and controls the periodic back-and-forth reciprocating variation of the spatial positions of the projection display element and the imaging lens group 3, so that the relative position or the overall position between the equivalent image plane 2 and the imaging lens group 3 is periodically varied, and the two-dimensional section 4 optically conjugated to the equivalent image plane 2 vibrates in the focal depth direction to perform the periodic back-and-forth reciprocating scanning, thereby realizing the continuous 3D display effect.

Example 4

The Bragg periodic scanning holographic imager comprises a projection display element, an imaging lens group 3 and a focal depth scanning mechanism 5 which are respectively arranged inside the Bragg periodic scanning holographic imager, wherein the focal depth scanning mechanism 5 is connected with the projection display element and controls the relative position and/or the whole position of a plurality of optical elements arranged in the imaging lens group 3 to change, the effective focal length of the imaging lens group 3 is periodically changed, as shown in figure 8, the mechanical zooming enables the space position of a two-dimensional section 4 to be periodically changed correspondingly, and the two-dimensional section 4 vibrates in the focal depth direction to carry out reciprocating scanning back and forth, so that the continuous 3D display effect is realized.

Example 5

The Bragg periodic scanning holographic imager comprises a projection display element, an imaging lens group 3 and a focal depth scanning mechanism 5 which are arranged inside the Bragg periodic scanning holographic imager respectively, wherein a flexible zoom lens with a zooming function is arranged in the imaging lens group 3, the focal depth scanning mechanism 5 is connected with the imaging lens group 3 and controls the effective focal length of the flexible zoom lens to change periodically, as shown in figure 9, the spatial position of a two-dimensional section 4 changes periodically correspondingly, and the two-dimensional section 4 vibrates in the focal depth direction to scan back and forth, so that a continuous 3D display effect is achieved.

It should be noted that the flexible zoom lens in embodiment 5 may be replaced by a liquid zoom lens or other lens with a zoom function.

Embodiments 1 to 5 respectively show that different modes are adopted to realize the volume scanning of reciprocating scanning back and forth on the two-dimensional section 4, and finally, the effect of continuous 3D display is achieved.

The projection display devices of embodiments 1-5 can be replaced by photographic sensitive devices according to the principle of reversible optical path, as shown in fig. 2, to achieve the effect of 3D photography.

As shown in fig. 7, in practical application, when the focal depth scanning mechanism 5 operates to perform reciprocating scanning (volume scanning) on the two-dimensional section 4, the equivalent image plane 3 optically conjugated with the two-dimensional section 4 also performs volume scanning;

the vibration controlled by the focal depth scanning mechanism 5 is actually in a corresponding relation with the scanning of the equivalent image plane 2, and the scanning of the two-dimensional section 4 in the focal depth direction is not in a linear corresponding relation with the scanning of the equivalent image plane 2 based on the lens imaging rule, so that the related design parameters are more convenient to design by taking the equivalent image plane 2 as a reference;

the amplitude of the equivalent image plane 2 in the depth-of-focus direction (i.e., the maximum displacement of the equivalent image plane 2 from the equilibrium position in the depth-of-focus direction) is L₁And mm, wherein the depth of the plurality of equivalent image planes 2 distributed along the depth-of-focus direction (i.e. the central distance between the foreground equivalent image plane 2 closest to the imaging lens group 3 and the background equivalent image plane 2 farthest from the imaging lens group 3) is L₂Mm, should satisfy L₁＜L₂The amplitude of the volume scan can be made relatively smaller;

the equilibrium position of the equivalent image plane 2 is a midpoint between two points, i.e., an amplitude point in the depth of focus direction of the equivalent image plane 2 and an amplitude point in the opposite direction of the depth of focus, and the amplitude points of the equivalent image plane 3 are shown in fig. 7: the maximum displacement position of the equivalent image surface 2 along the focal depth direction is defined as an amplitude point in the focal depth direction, and the maximum displacement position along the opposite direction of the focal depth is defined as an amplitude point in the opposite direction of the focal depth.

Considering that a continuous 3D picture space can be realized as long as the gap between adjacent equivalent image planes 2 can be completely swept through by the scanning action, the amplitude of the scanning is larger than the maximum distance between adjacent equivalent image planes 2, so that the scanning of a complete continuous space can be realized.

The design can be optimized as follows:

within the range of the design parameters, the proper design parameters can be guaranteed to be found on the premise that the amplitude is very small, so that the equivalent image surfaces 2 can sweep out a complete and continuous space in the space (in fact, the swept spaces of the adjacent equivalent image surfaces 2 are overlapped to a certain extent, and the complete avoidance of the overlapping is realizedThe problem of discontinuous longitudinal field depth is avoided, enough design margin is reserved, a part of a scanning period is allowed to be used for updating a display picture during design, the design flexibility is improved), and the scanning amplitude can be reduced to be small.

In practice, of course, the scanning amplitude may be made larger or smaller for scenes with less desired depth resolution in order to show finer picture effect.

In practical applications, the scanning frequency or equivalent frequency of the focal depth scanning mechanism 5 is preferably greater than

The frequency here refers to the reciprocal of the time interval between two consecutive passes of a certain spatial point in the same direction by the moving part, for example, the reciprocal of the time between two consecutive passes of the equilibrium position in the same direction during the reciprocal scanning of the imaging element 1. In addition, the case of performing scanning in a zooming manner may be equivalent to changing the focal length of the imaging lens assembly 3 from the initial focal length to the reciprocal of the focal length time again, where the initial focal length refers to the focal length of the imaging lens assembly 3 when the focal depth scanning mechanism 5 is not operating. Of course, it is also possible to measure the inverse of the time interval between two consecutive co-directional sweeps of the projected focal plane over a certain position in space.

When a 3D picture is displayed in a certain space, the focal plane needs to scan back and forth in the certain space to complete the update of the full-space picture, so the frame frequency of the 3D picture is the depth-of-field scanning frequency.

In addition, there is a special case that when the display space moves integrally, for example, in the process of moving from a close view to a long view, the depth of field in the switching process usually only needs to move in a single direction without scanning reciprocally, and then there is no concept of depth of field scanning, but the display depth of field switching process also needs to be completed in a relatively proper speed, otherwise, the picture is easy to jump or smear. We introduce the concept of equivalent frequency for this case: the equivalent frequency is the reciprocal of the time used in the process that the movement distance is equal to the maximum adjacent distance between the adjacent equivalent image planes 2 when the equivalent image planes 2 move unidirectionally relative to the imaging lens group 3.

For the case of performing the scanning in the zooming manner, the reciprocal of the time from the initial focal length to the focal length again (or the reciprocal of the time interval from the maximum focal length to the maximum focal length again) in the equivalent focal length variation process may be adopted, and the initial focal length refers to the focal length of the imaging lens group 3 when the focal depth scanning mechanism 5 is not in operation. Of course, it is also possible to measure the inverse of the time interval during which the projected focal plane is swept twice in succession over a certain position in space in the same direction.

In practical application, it is found that the larger the number n of the equivalent image planes 2 is, the denser the two-dimensional tangential planes are, and a relatively good stereoscopic display effect can be basically exhibited under a general display condition, so that only when the overall depth of field of the display content is largely changed, the focal depth of the display space needs to be matched again through the focal depth scanning action. For example, the display content of a movie screen is converted from an indoor scene to an open outdoor scene or an outer space star system scene, at this time, the displayed focal depth changes greatly, usually, the scene switching with large focal depth difference is completed in multi-frame images, and the conversion process is relatively slow, so that the display system only needs to be capable of realizing the focal depth switching slowly, and the scanning frequency (equivalent frequency) can be much less than the frame frequency of a 3D video. Thus, the requirements on a calculation and control system can be greatly reduced, and the system is more stable;

on the other hand, however, the larger n inevitably causes the total mass of the corresponding components to increase, the natural frequency of the system is lowered, and thus it is difficult to realize a higher scanning frequency, so that the lower limit of the scanning frequency must be lowered to protect the reliability of the system.

Usually, a picture is displayed in a relatively small range, such as an indoor scene, and at this time, the projection space of the equivalent image plane 2 may completely satisfy the display in the small space range, and at this time, a 3D scene may be restored more truly without performing a depth of focus scanning operation, or only a very small amplitude scanning is required to make the display effect finer.

Only when the display depth of field has a large variation range or the depth of field is greatly varied as a whole, the focal depth scanning needs to be performed with large amplitude scanning or integral translation.

It should be noted that many times the depth of field switching is not required to achieve a complete scan cycle.

For example, the image scene is slowly switched from a near scene to a far scene, and then stays in the far scene for a period of time, so that the focal depth scanning only needs to correspondingly adjust the depth of field of the image, and at this time, the equivalent frequency concept can be used. In summary, the scanning frequency can find a suitable design interval to satisfy the balance of the requirements in various aspects.

The following are several feedback scenarios for the user at the time of actual testing:

from a data point of view, for application scenarios where the general requirements are not particularly high, the scanning frequency (or equivalent frequency) is preferably larger than

When the user is in use, the comprehensive score of the user is higher than 60 points, so that the requirements of general users can be met;

of course, in order to further improve the 3D display effect and the overall performance score, n is preferably greater than or equal to 2 and the scanning frequency is preferably selected for some special application scenes

For some users pursuing extreme experience, n ≧ 3 and the scanning frequency are preferred

Generally, the depth resolution of human eyes is far lower than the lateral resolution, so that resolution distortion cannot be caused even if the pixel pitch in the depth direction is large, and therefore the pixel pitch of a projection picture in the depth direction can be set to be larger, so that a very real 3D picture can be projected under the condition of effectively reducing equipment and process cost.

Further, the mass Mg of the imaging element 1 satisfies the condition of the number n of equivalent image planes

The mass M of the imaging element 1 refers to the mass of the remaining part of the holographic imager after removing the auxiliary components such as the imaging lens group, the supporting mechanism and the wiring harness.

Taking a holographic projector as an example, a main application field of the holographic projector is a geometric holographic display system (refer to patent document 201910875975.1), and in such a system, the holographic projector is usually required to be in a motion state, so the mass of the holographic projector cannot be too large, otherwise, a component with too large mass is controlled to move, the inertia caused by the mass is too large, the operation difficulty is very large, the energy consumption is very large, and on the other hand, a large burden is caused to a support structure, and the whole system is very heavy and is not practical. And therefore their mass needs to be properly designed. Ideally, the smaller the overall quality, the better, but the equivalent image planes 2 must depend on the physical entity existence, so that the larger the number of equivalent image planes 2, the larger the overall quality. If one wants to design a holographic projector that is as light as possible, one inevitably needs to sacrifice the number of equivalent image planes 2, and if one wants to obtain denser equivalent image planes 2, one has to accept an increase in quality, which cannot be optimized simultaneously. The utility model provides a trade off design criteria between them, promptly

The design relation indirectly limits the total mass, gives the upper limit boundary of the holographic projector under the condition of different equivalent image surfaces 2, and when the upper limit boundary is exceeded, the practicability of the manufactured holographic projector is poor. For example, for living room display, 11 equivalent image planes 2 are usedThe depth of field is expressed, so that a very perfect display effect can be achieved, the mass of a moving object in a living room does not exceed 5000g at most, otherwise, on one hand, potential safety hazards to personnel exist, on the other hand, a supporting structure is very heavy, occupies a large amount of space and is not beautiful enough, and on the other hand, the boundary condition is met

As a design upper limit. Most households were also found in actual testing to be reluctant to accept products beyond this design boundary.

In addition, for desktop office type scenes, stricter design specifications are preferred as much as possible in designing, and preference is given to

At the moment, the whole structure and the display performance are more ideal, the actual measurement result is displayed, and the user generally evaluates the products meeting the design rule for more than 60 points;

further, it is preferable

At the moment, the whole system is more compact, flexible and attractive, the actual measurement result is displayed, and the user generally evaluates the products meeting the design rule for more than 70 points;

further, it is preferable

In this case, the design boundary is further tightened, the system is not only compact, but also some design elements can be added to make the system more attractive to customers. The actual measurement result shows that the user generally evaluates the products meeting the design rule for more than 90 points;

it should be noted that, the projection display element is used as the imaging element 1, the bragg period scanning type holographic imager of the present invention is used as a holographic projector, the photographing photosensitive element is used as the imaging element 1, the bragg period scanning type holographic imager of the present invention is used as a holographic imager, and the above design description is mainly an explanation description for the case of the holographic projector, but because the application cases of the holographic imager are very similar, the problem that needs to be considered by the holographic projector based on the principle that the light path is reversible, the holographic imager will also be encountered, and therefore the above design description is also applicable to the holographic imager.

The utility model discloses an imaging element 1 is inside can be equipped with a plurality of projection display chip respectively and shoot sensitization chip to realize the difunctional of projection and shooting.

The foregoing is a more detailed description of the present invention, taken in conjunction with the specific preferred embodiments thereof, and it is not intended that the invention be limited to the specific embodiments shown and described. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement, all should regard as belonging to the utility model discloses a protection scope.

Claims (9)

1. A Bragg period scanning holographic imager is characterized by comprising:

an imaging element (1) for providing a plurality of non-coincident or mutually parallel equivalent image planes (2), the number of said equivalent image planes (2) being n;

the imaging lens group (3) corresponds to the equivalent image surface (2) in position, is used for optical imaging and is provided with a plurality of two-dimensional sections (4); and

and the focal depth scanning mechanism (5) is respectively connected with the imaging element (1) and/or the imaging lens group (3) and is used for controlling the spatial position change of the imaging element (1) and/or the imaging lens group (3) so as to realize the volume scanning of the two-dimensional section (4).

2. A bragg period scanning holographic imager as claimed in claim 1, wherein: the scanning frequency or equivalent frequency of the focal depth scanning mechanism (5) is greater than

3. A bragg period scanning holographic imager as claimed in claim 1, wherein: the focal depth scanning mechanism (5) realizes the volume scanning of the two-dimensional section (4) by changing the space position between the equivalent image plane (2) and the imaging lens group (3) and/or the effective focal length of the imaging lens group (3).

4. A bragg period scanning holographic imager as claimed in claim 3, wherein: the focal depth scanning mechanism (5) realizes the volume scanning of the two-dimensional section (4) by changing the relative position and/or the overall position of the optical elements in the imaging lens group (3).

5. A bragg period scanning holographic imager as claimed in claim 3, wherein: the imaging lens group (3) at least comprises a liquid zoom lens or a flexible zoom lens.

6. A bragg period scanning holographic imager as claimed in claim 1, wherein: the focal depth scanning mechanism (5) controls the amplitude of the volume scanning along the focal depth direction to be L₁And the distribution depth of the equivalent image surfaces (2) along the depth of focus direction is L₂Mm, satisfy L₁＜L₂。

7. A bragg period scanning holographic imager as claimed in claim 1, wherein: the quality Mg of the imaging element (1) and the number n of the equivalent image planes (2) satisfy that:

8. a bragg period scanning holographic imager as claimed in claim 1, wherein: the imaging element (1) is a projection display element or a shooting photosensitive element.

9. A bragg period scanning holographic imager as claimed in claim 1, wherein: a plurality of projection display chips and a shooting photosensitive chip are arranged in the imaging element (1) so as to realize the double functions of projection and shooting.

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