CN111338175A - Transmission type geometric holographic display system - Google Patents
Transmission type geometric holographic display system Download PDFInfo
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- CN111338175A CN111338175A CN202010303254.6A CN202010303254A CN111338175A CN 111338175 A CN111338175 A CN 111338175A CN 202010303254 A CN202010303254 A CN 202010303254A CN 111338175 A CN111338175 A CN 111338175A
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- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B35/00—Stereoscopic photography
- G03B35/18—Stereoscopic photography by simultaneous viewing
Abstract
The invention relates to the field of 3D display, and discloses a transmission type geometric holographic display system which comprises a display element, a transmission type geometric holographic screen, a supporting structure and a controller, wherein the display element adopts at least one common projection device capable of projecting a two-dimensional picture, the number of viewpoints of the transmission type geometric holographic display system is n, the mean value of the diameters of light transmission parts of outermost lenses of the common projection device contained in the display element is D decimeters, and the mean value of the projection light source power of the common projection device contained in the display element is P watts, so that the requirements of meeting the requirements of the transmission type geometric holographic display system on the two-dimensional picture projection device are met
The invention adopts the common projection equipment to project a two-dimensional picture on a certain focal plane in space, and the focal depth of the projected picture is adjusted by the controller to realize the field depthThe picture display of the information shows a more vivid 3D effect, overcomes the limitation of 3D film source shortage, greatly reduces the cost and improves the practicability; meanwhile, optimized design parameter configuration is provided, and the purpose of giving consideration to both display effect and system reliability is achieved.
Description
Technical Field
The invention relates to the field of 3D display, in particular to a transmission type geometric holographic display system.
Background
The 3D display technology may provide depth information to exhibit more visual information than the conventional 2D display technology, so that the degree of restitution of the display image is higher. The 3D display technology is therefore a very popular technology in current academic research. The 3D display scheme based on the holographic technology can restore the light field distribution of the real physical world in principle, so that all optical characteristics of the 3D scene are completely restored. The traditional holographic display technology is to record the light intensity information and the phase information of a scene by utilizing the fluctuation characteristic of light, thereby realizing the recording of the light intensity, the color and the depth of field of the scene. However, coherent light is needed for shooting and displaying in this way, the light path setting during the shooting and displaying process is very harsh, and slight disturbance of the environment can cause shooting failure, so that the method cannot be really applied in life.
Currently, mainstream 3D display solutions (such as 3D movies in theaters) are all pseudo 3D display images based on parallax image pairs (stereo image pairs), which cannot display real 3D images, and the physical focal depth of the display image is fixed, so that the display of scenes with different focal depths cannot be realized. Although many 3D display technologies have been proposed, none of them can really display a large-scale, stable, high-quality 3D image.
The patent application No. 201910875975.1 discloses a new holographic display scheme, as shown in fig. 1, which includes a holographic projector 1, a projection screen 2, an interactive response unit 3, a processor 4 and a motion actuator 5, wherein the processor 4 sends projection data information to the holographic projector 1 to control the projection picture and the picture depth of the holographic projector 1, and controls the motion actuator 5 to adjust the position of the holographic projector 1 relative to the projection screen 2 according to the received positioning information of human eyes and user interaction information acquired by the interactive response unit 3, so that the user can normally view a 3D picture. But at the present stage, the display advantages are difficult to be realized due to the lack of 3D film sources available for the display. Moreover, the holographic projector 1 as a display element can realize 3D display only by a very precise eye tracking means, and the system is complex and has high cost.
Meanwhile, the optical parameter setting of the display system needs to be carefully designed to ensure the ideal display effect and the reliability of the display system, otherwise, the display system may not achieve the ideal display effect or ensure the reliability due to the inappropriate display parameters. For example, for a display system with a small number of viewpoints, the utilization rate of the light source is relatively high, and at this time, if the power of the light source is too high, the pattern is too bright, so that the eyes of a user are exposed to strong light to feel uncomfortable when watching the pattern, and of course, if the light source is too dark, the brightness of the picture is also low, and the contrast ratio in the daytime is poor. In addition, from the viewpoint of system reliability, the higher the light source power, the higher the system failure rate, and the lower the service life.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the defects of the prior art, the transmission type geometric holographic display system is provided, a two-dimensional picture is projected on a certain focal plane in a space by adopting common projection equipment, the focal depth of the projected picture is adjusted by a controller, the picture display with depth of field information is realized, a more vivid 3D effect is presented, the limitation of 3D picture source shortage is overcome, simultaneously, optimized design parameter configuration is provided, and the purpose of considering both the display effect and the system reliability is achieved.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a transmissive geometry holographic display system comprising:
a display element for projecting picture information in space;
the transmission type geometric holographic screen is provided with a screen which converges an image point on one side of the transmission type geometric holographic screen to the other side of the transmission type geometric holographic screen to form a conjugate image point, the position of the screen corresponds to that of a display element, and the screen is used for converting an image projected by the display element to an optical conjugate position relative to the transmission type geometric holographic screen;
the support structure is respectively matched with the display element and the transmission type geometric holographic screen and provides physical structural support for the display element and the transmission type geometric holographic screen;
the controller is electrically connected with the display element, the display element adopts at least one common projection device capable of projecting a two-dimensional picture, the number of viewpoints of the transmission type geometric holographic display system is n, the average value of the diameters of light transmission parts of outermost lenses of the common projection device contained in the display element is D decimeter, the average value of projection light source power of the common projection device contained in the display element is P watt, and the requirements are met:
further, the display element comprises a general projection device having a mean display luminous flux of L lumens, which satisfies the following relation with the number of viewpoints n of the transmissive geometric holographic display system:
n1.27·L≤24000。
further, the number of viewpoints n of the transmissive geometry holographic display system, the average value D decimeter of the diameter of the light-transmitting portion of the outermost lens of the ordinary projection device included in the display element, and the average display luminous flux L lumens of the ordinary projection device included in the display element satisfy:
further, a plurality of common projection devices adopted by the display element can be replaced by projection devices capable of realizing three-dimensional picture or two-dimensional picture group display distributed in different space depths.
Further, the projected focal depth of the display element is adjustable in a space other than 0.1m and 0.1m from the outermost lens of the lens.
Further, the transmission type geometric holographic screen adopts a flexible holographic screen.
Further, the supporting structure is a movable or deformable structure and is electrically connected with the controller, and the controller can control the supporting structure to realize the relative movement and/or the overall movement of the display element and the transmission-type geometric holographic screen, so that the visual window of the system always covers the eyes of the user.
The interactive action capturing unit is electrically connected with the controller and used for identifying the interactive action of the user and sending the interactive action information of the user to the controller, and the controller adjusts the content of the displayed picture according to the received interactive action information of the user, which is acquired by the interactive action capturing unit, so that the interactive action between the user and the picture is realized.
The controller controls the support structure to make corresponding action response according to the received human eye positioning information acquired by the human eye tracking unit, so as to adjust the relative position and/or the overall spatial position of the display element and the transmission-type geometric holographic screen, and enable the eyes of a user to be always in the visual space of the system.
Further, the visible space is a space in which the center of the outermost lens of each projection apparatus of the display element is an origin, the outer normal of the center of the lens is a Y-axis direction, a straight line passing through the origin and perpendicular to the horizontal plane is an X-axis, and a straight line passing through the origin and perpendicular to the X-axis and the Y-axis is a Z-axis, and which satisfies the following relational expressions with respect to an optically conjugate coordinate system (X ', Y ', Z ') of the transmission type geometric hologram screen:
wherein K is an expansion constant with unit of decimeter and the range of K is more than 0 and less than 0.08;
m is a conjugate deviation constant, and m is within the range of 0-5.
Compared with the prior art, the invention has the advantages that:
1. the two-dimensional picture is projected on a certain focal plane in space by adopting common projection equipment, the focal depth of the projected picture is adjusted by the controller, the picture display with depth-of-field information is realized, a more vivid 3D effect is presented, the limitation of 3D picture source shortage is overcome, and meanwhile, the common projection equipment is used as a display element, so that the cost can be greatly reduced, and the practicability is improved;
2. the reasonable optical parameter setting can effectively improve the display effect and the reliability of the holographic display system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings 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 a schematic diagram of a prior art holographic display system,
figure 2 is a schematic diagram of a transmissive geometry holographic display system of the present invention,
FIG. 3 is a system diagram of the human eye tracking unit 102 and the interactive motion capture unit 101 added to the system diagram of FIG. 2;
FIG. 4 is a schematic view of several off-screen display configurations of the present invention;
FIG. 5 is a schematic diagram of a system configuration with multiple viewpoints according to the present invention;
FIG. 6 is a schematic view of a space 0.1m away from the outermost lens of the projection lens;
FIG. 7 is a schematic diagram of a coordinate system (X ', Y ', Z ') in which an ellipsoidal visual space exists;
figure 8 is a schematic view of an ellipsoidal viewing space or window,
the reference numbers are as follows:
the holographic projector 1, the projection screen 2, the interactive response unit 3, the processor 4, the motion executing mechanism 5, the display element 6, the transmission type geometric holographic screen 7, the supporting structure 8, the controller 9, the interactive action capturing unit 101 and the human eye tracking unit 102.
Detailed Description
The following detailed description of the present invention is given for the purpose of better understanding technical solutions of the present invention by those skilled in the art, and the present description is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
It is to be understood that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like are used in a generic and descriptive sense only and not for purposes of limitation, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like are used in the generic and descriptive sense only and not for purposes of limitation, as the term is used in the generic and descriptive sense, and not for purposes of limitation, unless otherwise specified or implied, and the specific reference to a device or element is intended to be a reference to a particular element, structure, or component. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not imply that the components are required to be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Referring to fig. 2 and 3, the present invention provides a transmissive geometry holographic display system comprising a display element 6, a transmissive geometry holographic screen 7, a support structure 8 and a controller 9;
the display element 6 is used for projecting picture information in space, the invention adopts a common projection device capable of projecting a two-dimensional picture as the display element 6, can realize that the two-dimensional picture is projected on a certain focal plane in space, and then the depth of field and the picture content of the two-dimensional picture are adjusted by the controller 9. Generally, 3D film sources in a cinema are in the form of a stereo image pair, and a 3D effect is expressed by binocular parallax, but the actual picture focal depth is fixed at one position, so that visual fatigue is caused. The system of the invention can move the picture equivalent focal depth to a reasonable position because the projection and focal depth are adjustable, thereby avoiding the problem that the 3D focal depth is different from the actual focal depth and presenting a more vivid 3D effect. Compared with a holographic projector as the display element 6, the method can effectively reduce the cost, and particularly, the common projection equipment can use a common projector;
or directly using a holographic projector as the projector 6 to project a 3D picture or a series of two-bit picture groups distributed in different depths of field in the space; for example, a common projection device may be further optically designed to realize 3D display based on a single projector, and reference may be made to an all-solid-state holographic projector with application number 202010029144.5, and a technical solution for realizing three-dimensional picture display by adding some optical elements inside the projector to perform optical design is not specifically limited herein;
the transmission type geometric holographic screen 7 is a screen which converges an image point on one side of the transmission type geometric holographic screen 7 to the other side thereof to form a conjugate image point, the position of the screen corresponds to the display element 6, and the screen is used for converting an image projected by the display element 6 to an optical conjugate position relative to the transmission type geometric holographic screen 7, preferably a flexible holographic screen is used, so that a scroll screen or a folding screen can be made, the whole system is more compact and portable, and a hard screen can be used in proper occasions;
when the 2D picture needs to be compatibly displayed, the transmission type geometric holographic screen 7 can be replaced by a common projection screen, such as a common rear projection screen;
the supporting structure 8 is respectively matched with the display element 6 and the transmission type geometric holographic screen 7 to provide physical structural support for the display element and the transmission type geometric holographic screen, specifically, the supporting structure 8 can be made into a support frame with a fixed structure, at the moment, the whole display system is fixed, and a user can observe a picture only in a fixed direction;
the controller 9 is electrically connected with the display element 6, and the display element 6 can adjust the depth of field and the display content of the projection picture according to the control signal of the controller 9;
in order to increase the flexibility of the display system, we can also set the support structure 8 as a movable or deformable structure, electrically connect the support structure 8 and the controller 9, the support structure 8 makes corresponding response actions according to the control information of the controller 9, and implement the relative movement and/or the overall movement of the display element 6 and the transmissive geometric holographic screen 7, so that the visual window of the system always covers the eyes of the user, so that the user can normally view the picture in different orientations, it should be noted that the support structure 8 is a general prior art, and those skilled in the art can design themselves according to the spatial conditions of the practical application, for example: the deformable structure can be easily designed by using a plurality of hinge structures and structures similar to the umbrella shaft, and is not particularly limited;
as a preferable solution, the holographic display system of the present invention further includes an interactive action capturing unit 101 electrically connected to the controller 9, the interactive action capturing unit 101 is configured to recognize an interactive action of a user and send user interactive action information to the controller 9, the controller 9 adjusts display screen content according to the received user interactive action information acquired by the interactive action capturing unit 101, so as to implement the interactive action between the user and the screen, specifically, a camera is used in combination with a machine vision technology to recognize a gesture action of the user to acquire the interactive information of the user, so as to control the screen display content or control the movement of the supporting structure 8 to adjust the spatial position and posture of the projection device and/or the transmissive geometric holographic screen 7, and the controller 9 may also adjust the display screen content in real time according to the received user interactive action information acquired by the interactive action capturing unit 101, the method includes the steps that interaction between a user and a picture is achieved, for example, the picture is controlled to translate according to a translation gesture signal, or operations such as amplification, zooming-in, zooming-out and touch of the picture are controlled according to other corresponding interaction;
the setting of the interactive motion capture unit 101 has positive significance for application scenarios like wearable applications where the spatial position of the user relative to the display system is fixed;
in addition, for an application scenario that the spatial position of the user changes in real time relative to the display system, a human eye tracking unit 102 electrically connected to the controller 9 needs to be arranged, the human eye tracking unit 102 is used for tracking the position of human eyes and sending the positioning information of the human eyes to the controller 9, the controller 9 controls the support structure 8 to make a corresponding action response according to the received human eye positioning information acquired by the human eye tracking unit 102, so as to adjust the relative position and/or the overall spatial position of the display element 6 and the transmission-type geometric holographic screen 7, so that the user's eyes are always in the visible space of the system, and thus the user's eyes can always receive the projection information even in a moving state and normally watch the picture.
In practical applications, the human eye tracking unit 102 and the interactive motion capture unit 101 may be integrated in the same device, for example, a machine vision camera device is used.
When a common projector is used as the display element 6, the controller 9 sends the picture and the average focal depth information of the picture to the projector, and the projector adjusts the projection focal depth by itself, so that the projector can project the picture to a specific focal depth position for the human eyes to watch.
It should be noted that a common projector generally has an auto-focusing function, and when the projector is started, the projector can measure the distance from the screen to the projector according to a built-in distance sensor, and then drive a lens to adjust to a proper position, so that the projection focal depth coincides with the screen; in the system of the present invention, the distance sensor carried by the system can be removed, so that the controller 9 directly sends the focal depth data to the projector to realize the control of the projected focal depth, and the specific implementation manner is the existing mature hardware communication technology, which is not described herein again.
Compared with the traditional display system, the transmission type geometric holographic display system has a very special place, which can not be watched by a large number of users at the same time like the traditional 2D display device, and for the convenience of expression, the concept of a viewpoint is introduced:
if the display system can provide a viewing window for one eye, the system has a point of view. For a binocular display system, two eyes can watch simultaneously, so the number of viewpoints is 2. When the display system is available for n eyes to view simultaneously, the number of viewpoints is n. In actual design, the structure of the system needs to be reasonably set under the condition of considering practicability.
As shown in fig. 4, in case a, corresponding to the use of a large-aperture projector, the outermost lens of the projector may cover both eyes of the user with respect to the optical conjugate area (also called a mirror symmetry area, which may be called a viewing window) of the transmissive geometric holographic screen 7, and at this time, although the area between both eyes can also be used for viewing images in principle, it is impossible to use the projector in practical conditions, and only two eyes can be used for viewing at the same time, so that this situation is equivalent to two viewpoints;
in the case of b to d, the projection optics of the two projectors form two separate sub-areas with respect to the optically conjugate area of the transmissive geometrical holographic screen 7, corresponding to the use of two small-aperture projectors. When the distance between the two sub-regions is exactly matched with the distance between the human eyes, the two eyes can watch the images simultaneously (b situation), so that two viewpoints exist;
when the interval between two sub-regions is smaller than the interval between human eyes (c case) or larger than the interval between human eyes (d case), only one of the two eyes can view an image and thus only one viewpoint.
Similarly, as shown in fig. 5, when the number of projectors is greater, the number of viewpoints of the system is increased accordingly, the number of viewpoints is determined according to the specific situation of a to d, and the number of viewpoints of the display system is n, which is related to the size and number of lenses of the projectors used.
Similarly, the spatial position relationship among users under the use situation needs to be considered when the multi-user system is designed, the spatial distribution condition among all windows is reasonably designed, and the condition that the actual available viewpoint of the system is smaller than the design viewpoint is avoided. An effective design strategy is to design the support structure 8 reasonably to have a structure adjusting function, for example, the distance or the spatial position between two projectors can be adjusted, so that the geometric form of the support structure 8 can be flexibly adjusted according to the interpupillary distance of a user and an application field to adapt to actual requirements when the projector is used.
It should be noted that, when the projection system is compatibly switched to the 2D projection mode (for example, a projection focal plane of the projector is adjusted to directly project a 2D picture on the transmission-type geometric holographic screen 7, or a common projection receiving screen is used to replace or be placed on the front surface or the rear surface of the transmission-type geometric holographic screen 7 to perform receiving display of the 2D projection picture), an image focal plane coincides with the screen, the number of viewpoints is greatly increased, but these viewpoints have great viewing limitations, only the picture on the screen can be viewed, and the off-screen picture output by the display system cannot be viewed, so that the number of viewpoints cannot be counted into the number of real viewpoints, and the actual effective viewpoint should be the viewpoint capable of viewing the picture in all modes of the system, including the viewpoint capable of viewing the off-screen display content on the screen, in front of the screen, and behind the screen.
The conventional 2D display devices, such as televisions, projectors, computers, etc., have a large number of viewpoints, and can be viewed by many users at the same time, because the light emitted from the light source has high divergence and no directivity, and thus has a high requirement on brightness. However, for the holographic display system of the present invention, the number of viewpoints is small, and light emitted by the display device (such as a holographic projector or a common projector) can be collected to the position of the window very efficiently to be received by human eyes, so that if the light intensity is too strong, dizziness, unclear images, and even injury to human eyes are easily caused, and meanwhile, excessively high luminous flux often requires the light source (such as a bulb, an LED lamp and the like inside the projector) to operate under high power, and the service life of the light source can be greatly shortened when the light source operates in a high power mode for a long time, so that the luminous flux cannot be designed to be excessively high. However, as the number of viewpoints increases, the total luminous flux of the display system also needs to be increased to ensure that each viewpoint can provide a clear picture.
The number of viewpoints of the transmission-type geometric holographic display system is n, the mean value of the diameters of the light transmission parts of the outermost lenses of the projection equipment included in the display element 6 is D decimeter (dm), the average display luminous flux L lumen (lm) of the projection equipment included in the display element 6, and the display luminous flux visual dot product is n1.27L, taken together, combined with the actual test effect, shows that the luminous flux viewpoint product satisfies: n is1.27When L is not more than 24000, a relatively good display effect and system reliability can be ensured.
The method for measuring the display luminous flux l (lm) of a single projection device can refer to the test method of ANSI lumens:
1) the distance between the projector and the screen in the display system is set as follows: 2.4 meters;
2) screen is 60 inches;
3) measuring the illuminance of each point on nine cross points in the shape of the Chinese character 'tian' on the screen by using an illuminometer, and calculating the average illuminance of 9 points;
4) the average luminance multiplied by the projected picture area is ANSI lumens, which is the display luminous flux according to the present invention.
For different displayed pictures, the test value of L may have a large difference, and in the actual test, a full white picture is preferably displayed for testing, that is, each pixel is displayed as white;
when the illumination area of the projector cannot be well matched with the screen, the illumination test is carried out according to the actual illumination area to carry out a point taking test, preferably 8 points and 1 point in the illumination area, wherein the 8 points and the 1 point are uniformly selected in a light band which is within 10-30 cm of the illumination area from the outer boundary of the illumination area, the distance from the center of the screen is not more than 20cm, the illumination test is carried out on 9 points in total, and then the average value of the 9 illumination values is multiplied by the actual area of the illumination area to obtain a display light flux value.
For applications that include only one projection device, the display luminous flux may be tested in the manner described above (the display luminous flux of a single projector is the same as the average display luminous flux), and when multiple projectors are used, the luminous flux of each projection unit may be tested separately and then averaged to serve as the value of the display luminous flux.
In addition, in an actual test, different design structures (such as differences in sealing and heat dissipation) also have a more significant influence on the service life of the system, so that in the actual test process, different design structures may bring certain fluctuation to actually measured data, but the overall trend does not change, and the optimal value of the display configuration parameter does not change.
The present invention will be further explained below by taking a general projector as an example of the display element 6:
example 1: a projector with a lens diameter of 0.5dm is used as the display element 6, and the viewpoint number n is 1, so that a single user can use a single eye to watch;
typically, the number of eyes of the user is even, the number of viewpoints n is set to be even,
examples 2 to 24: 1 projector with a lens diameter larger than 6.5dm or 2 projectors with a lens diameter smaller than 6.5dm is adopted as the display element 6, and the number of viewpoints n is 2, so that the display element can be viewed by two eyes of a single user;
example 25: 4 projectors with the lens diameter of 0.4dm are adopted as a display element 6, and the number n of system viewpoints is 4, so that a double user can watch the projectors simultaneously;
example 26: 6 projectors with a lens diameter of 0.3dm are used as the display elements 6, the number of viewpoints n is 6, and three persons can watch the projectors simultaneously;
example 27: as the display element 6, 8 projectors with a lens diameter of 0.2dm were used, and the number of viewpoints n was 8, which were viewed by four persons at the same time, as shown in the following table:
the data for examples 1-27 show that: display luminous flux visual point product n1.27When L is not more than 24000, the display effect is good, the user scores are all over 80 points, and the luminous flux visual point product n is displayed in comparative example 11.27L is 31351, the user score is low, the picture is dazzling, and the actual display effect is not good enough.
In practical use, in addition to the design relationship between the number of viewpoints n and the light flux L, matching between the aperture size of a single projector and the light flux is also required. When the aperture of a single projector is large, the visual utilization rate of display light is low, and many light rays can only reach areas outside human eyes, so that the light flux needs to be increased appropriately at this time, and according to the application of the above embodiments 1 to 27, in practical application, the following expression can be referred to for design:
based on the influence of the light source power on the display effect and reliability of the system. The life of the projector internal light source is often greatly reduced when the projector internal light source works in a high-power mode, so that the projector internal light source can work in a low-power mode as much as possible. However, when the number of viewpoints is large or when the aperture of a single projector is large, the visual utilization rate of display light is low, and many light rays can only reach the region outside human eyes, so that the power of the light source needs to be increased appropriately to improve the luminous flux at this time, the average value of the projection light source power of the projection device included in the display element 6 is P watts (W), and tests show that the system can operate under an optimal condition when the following relation is satisfied:
the measurement of the light source power P of the projection device can directly test the voltage at two ends of the light source and the current passing through the light source in the normal working state, and then multiply to obtain the power value.
On the basis of the embodiments 1 to 27, the light source power p (w) is introduced for explanation, which is specifically shown in the following table:
the data show that: power apparent dot product
The display effect is better, the user scores are more than 80 points, and the power in comparative example 1 is according to the dot product
679, the user score is low, the picture is dazzling, and the actual display effect is not good enough. In addition, when the power of the light source is less than 400W, the design life of 5 years can be basically met, and the reliability can be further ensured.
The general projector used in the above embodiment may be replaced with a holographic projector or other projection device capable of realizing three-dimensional picture display. While the above-mentioned design formulas relating to the number of viewpoints, the power of the light source and the display luminous flux are also used for the holographic projector.
In addition, practical tests show that 3000 hours can still work normally in the high-temperature and high-humidity environment (85 ℃ and 85% relative humidity) accelerated tests of examples 1-27, and a light source is damaged and cannot emit light in the comparative example 1 at 3000 hours, so that the service life can be greatly shortened due to unreasonable design parameters, the tests are commonly called double 85 aging tests, and the 3000 hour accelerated aging test is equivalent to the minimum service life standard of 5 years under the actual working condition.
The data of the above embodiments may also illustrate: the display effect and the reliability of the holographic display system can be effectively improved through reasonable optical parameter setting.
The principles of the display system of the present invention may be found in reference to application No. 201910875975.1, which is briefly described herein: the projector can project pictures at different depths in space, that is, extra depth of field information can be provided for the projected pictures, but the pictures projected by the projector are all divergent light and cannot be directly viewed by human eyes, which is also the reason that a conventional projection system must use a receiving screen.
The light path conversion function of the transmission-type geometric holographic screen 7 can enable the divergent light projected by the projector to be converged to the optical conjugate position of the projector relative to the transmission-type geometric holographic screen 7, namely the mirror image position of the projector, so that converged light is formed and can be directly watched by human eyes. So, although the holographic display system of the present invention uses a transmissive geometrical holographic screen 7, its effect is completely different from that of the conventional projection display system. The receiving screen of conventional projection systems is used to randomly scatter light for viewing by a user. The transmission type geometric holographic screen 7 acts more like a special optical element which can perform specific optical transformation on light rays, and the light rays emitted by the light spot on one side of the screen are converged to an area with extremely small mirror image position of the light spot relative to the screen, so that a converged real image point suspended in the air is formed. This unique imaging feature allows it to image at different depths in space (off-screen imaging) to achieve true 3D display.
From the analysis of the display principle of the invention, it can be found that the picture seen by the user in use is completely consistent with the picture projected by the projector. How far away the image projected by the projector is from the outermost lens of the projector, and how far away the image seen by the user is from the eyes. In life, the photopic distance of human eyes is generally 25cm, and the distance for watching the nearest object is generally beyond 10cm, so that a projector (a common projector or a holographic projector) with the projection focal depth capable of being adjusted in a space (as shown in figure 6) more than 0.1m away from the outer surface of the outermost lens of a projection lens can be preferred when the projector is selected.
When the user is in a static state, the user can normally watch the picture only by adjusting the system structure to enable the eyes of the user to be covered by the window, but if the user is in a moving state, the eyes can be easily separated from the window, so that the user cannot normally watch the picture. Therefore, for an application scenario in which the user cannot be completely in a static state, it is very important to increase the eye-positioning tracking of the user and then adjust the spatial position of the window in real time so that the window always covers the eyes of the user. However, in an actual scene, the parameters of components of the display system are different, and it is difficult to find a set of tracking mode suitable for all systems. In principle, if the user eye movement track can be very accurately positioned, then the window is driven to accurately track the user eye movement track by adjusting the relative position and the overall spatial position between the projector and the transmission-type geometric holographic screen. However, it is very difficult to track the user's eyes and control the position of the window accurately, and even if it is realized, it is not practical.
In fact, because the window has a certain size, human eyes can view the picture only in the window, so that the user does not need to completely and accurately track the movement track of the user's eyes during movement as long as the user's eyes can be approximately tracked and guaranteed to be in the window, even if the user's eyes slightly deviate from the window, but the picture can be normally viewed even if the pupils intersect with the window.
The above discussion is mainly directed to the situation that the user moves up and down left and right relative to the screen, and in addition, when the user moves back and forth, the user can completely and normally view the picture without deviating from the center of the window too much. In summary, the tracking of the user's eyes does not need to be particularly accurate, and the use requirement can be met only by ensuring a certain accuracy. Specifically, as shown in fig. 8, there is an intersecting diamond region for the light above and below the screen, and in principle, the picture can be observed only by adjusting the support structure in real time to make the eyes of the user always in the diamond visible space, but the problem of tracking loss is more likely to occur at the position close to the angular position of the diamond, so that a relatively small ellipsoid visible region is further defined in the diamond region, and the probability of tracking loss is reduced.
As shown in fig. 7, the ellipsoidal visible space is a space in which the following relational expression is satisfied in a coordinate system (X, Y, Z) in which the center of the outermost lens of each projector of the display device 6 is the origin, the outer normal of the center of the lens is the Y-axis direction, a straight line passing through the origin and perpendicular to the horizontal plane is the X-axis, and a straight line passing through the origin and perpendicular to the X-axis and the Y-axis is the Z-axis, with respect to the optically conjugate coordinate system (X ', Y ', Z ') of the transmissive geometric hologram panel 7:
wherein K is an expansion constant with the unit of dm and the range of K is more than 0 and less than 0.08;
m is a conjugate deviation constant, and m is within the range of 0-5.
The above expression is a space surrounded by an ellipsoid, wherein the value of m influences the length of the ellipsoid in the y-axis direction. As can be seen from fig. 8, the visual space has a certain extension in the Y ' axis direction, and actual tests show that the certain extension length of the visual space in the Y ' axis direction is about 6 times of the lens diameter D, and a clear picture can be seen in this range, but in consideration of the tracking effect, a better display effect can be easily achieved in the range that the extension length in the Y ' axis direction is less than 5 times of the lens diameter. In addition, practical tests found that:
when m is 5, all display areas of the picture can be clearly seen, and only in a local boundary area, the picture is slightly poor in definition but can still clearly distinguish display details;
when m is 3, all display areas of the picture can be clearly seen, the picture is clear even in a boundary area, and the tracking stability is very good;
when m is 2, the whole display range of the picture is complete, the display details are very clear, the tracking stability is good, and the tracking device is suitable for desktop office scenes due to occasional loss;
when m is 1, the whole display range of the picture is complete, the display details are very clear, the tracking stability is slightly poor, the tracking loss frequency is increased to a certain extent, and the method is suitable for viewing and entertainment application scenes;
k and D determine the cross section of a visual space in a plane vertical to the Y' axis, and in principle, a picture can be observed within the diameter range of the projection lens, and in fact, as long as human eyes are intersected with the optical conjugate area of the projection lens, even if people can see the picture without being completely within the optical conjugate area of the projection lens, an expansion constant K is introduced, the numerical value of the expansion constant K depends on the diameter size of human eyes, usually, the maximum value of the diameter of pupils of the human eyes is 0.08dm, and therefore, 0.08dm is taken as the expansion constant.
Although mathematically m may not take the value 0, taking 0 here has a physical meaning, i.e. a point on a plane where Y' is all equal to 0.
The invention can select the same model when using a plurality of projectors (common projectors or holographic projectors), and can also select different models according to the requirements of actual application scenes.
The display system can avoid visual fatigue caused by long-time watching of a fixed focal depth picture by the user due to the adjustable focal depth, thereby avoiding the occurrence of myopia and improving the vision level.
The invention can be used for fixed display, such as office, family room audio and video, vehicle-mounted display and the like, and also can realize the fields of small mobile display, head-mounted display and the like, and the quality of the projection equipment is selected under different application scenes:
desktop application: preferably a projection device having a mass of less than 5 kg;
a mobile terminal: a projection device preferably having a mass of less than 300 g;
wearing application: projection devices having a mass of less than 100g are preferred.
When the invention is implemented, optical elements such as an antireflection film, a light absorption film, an optical filter and the like can be added properly to further improve the effect of the system.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (10)
1. A transmissive geometry holographic display system comprising:
a display element (6) for projecting picture information in space;
the transmission type geometric holographic screen (7) is a screen which converges an image point on one side of the transmission type geometric holographic screen (7) to the other side thereof to form a conjugate image point, the position of the transmission type geometric holographic screen corresponds to that of the display element (6), and the transmission type geometric holographic screen is used for converting an image projected by the display element (6) to an optical conjugate position relative to the transmission type geometric holographic screen (7);
a support structure (8) respectively matched with the display element (6) and the transmission type geometric holographic screen (7) to provide physical structural support for the display element and the transmission type geometric holographic screen;
a controller (9) electrically connected to the display element (6), characterized in that: the display element (6) adopts at least one common projection device capable of projecting a two-dimensional picture, wherein the number of viewpoints of the transmission type geometric holographic display system is n, the average value of the diameters of light transmission parts of outermost lenses of the common projection device contained in the display element (6) is D decimeter, the average value of projection light source power of the common projection device contained in the display element (6) is P watt, and the requirements are as follows:
2. the transmissive geometry holographic display system of claim 1, in which: the display element (6) comprises a general projection device with a mean display luminous flux of L lumens, which satisfies the following relation with the number of viewpoints n of the transmissive geometric holographic display system:
n1.27·L≤24000。
3. the transmissive geometry holographic display system of claim 2, in which: the number of viewpoints n of the transmissive geometry holographic display system, the average value D decimeter of the diameter of the light-transmitting part of the outermost lens of the ordinary projection device comprised by the display element (6) and the average display luminous flux L lumens of the ordinary projection device comprised by the display element (6) are such that:
4. a transmissive geometry holographic display system according to any of claims 1 to 3, in which: the plurality of common projection devices adopted by the display element (6) can be replaced by projection devices which can realize three-dimensional picture or two-dimensional picture group display distributed in different space depths.
5. The transmissive geometry holographic display system of claim 1, in which: the projection focal depth of the display element (6) is adjustable in a space which is 0.1m away from the outermost lens of the lens and is beyond 0.1m away from the outermost lens of the lens.
6. The transmissive geometry holographic display system of claim 1, in which: the transmission type geometric holographic screen (7) adopts a flexible holographic screen.
7. The transmissive geometry holographic display system of claim 1, in which: the support structure (8) is a movable or deformable structure and is electrically connected to a controller (9), wherein the controller (9) is capable of controlling the support structure (8) to effect relative and/or global movement of the display element (6) and the transmissive geometrical holographic screen (7).
8. The transmissive geometry holographic display system of claim 7, in which: the device is characterized by further comprising an interactive action capturing unit (101) electrically connected with the controller (9), wherein the interactive action capturing unit (101) is used for identifying the interactive action of the user and sending the interactive action information of the user to the controller (9), and the controller (9) adjusts the content of the display picture according to the received interactive action information of the user acquired by the interactive action capturing unit (101).
9. The transmissive geometry holographic display system of claim 8, in which: the system is characterized by further comprising a human eye tracking unit (102) electrically connected with the controller (9), wherein the human eye tracking unit (102) is used for tracking the position of human eyes and sending the positioning information of the human eyes to the controller (9), and the controller (9) controls the supporting structure (8) to make corresponding action response according to the received human eye positioning information acquired by the human eye tracking unit (102) so as to adjust the relative position and/or the overall spatial position of the display element (6) and the transmission type geometric holographic screen (7), so that the user eyes are always in the visual space of the system.
10. The transmissive geometry holographic display system of claim 9, in which: the visual space is a space which takes the center of the outermost lens of each projection device of the display element (6) as an origin, the outer normal of the center of the lens as a Y-axis direction, a straight line passing through the origin and perpendicular to the horizontal plane as an X-axis, and a straight line passing through the origin and perpendicular to the X-axis and the Y-axis as a Z-axis, and satisfies the following relational expressions relative to an optical conjugate coordinate system (X ', Y ', Z ') of the transmission type geometric holographic screen (7):
wherein K is an expansion constant with unit of decimeter and the range of K is more than 0 and less than 0.08;
m is a conjugate deviation constant, and m is within the range of 0-5.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010303254.6A CN111338175A (en) | 2020-04-17 | 2020-04-17 | Transmission type geometric holographic display system |
| US17/753,804 US20220365363A1 (en) | 2019-09-17 | 2020-08-21 | Holographic display system |
| PCT/CN2020/110405 WO2021052104A1 (en) | 2019-09-17 | 2020-08-21 | Holographic display system |
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| CN202010303254.6A CN111338175A (en) | 2020-04-17 | 2020-04-17 | Transmission type geometric holographic display system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021052104A1 (en) * | 2019-09-17 | 2021-03-25 | 荆门市探梦科技有限公司 | Holographic display system |
| CN112857756A (en) * | 2021-04-23 | 2021-05-28 | 广州市诺以德医疗科技发展有限公司 | Holographic fixed parallax stereoscopic vision degree quantizing device |
-
2020
- 2020-04-17 CN CN202010303254.6A patent/CN111338175A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021052104A1 (en) * | 2019-09-17 | 2021-03-25 | 荆门市探梦科技有限公司 | Holographic display system |
| CN112857756A (en) * | 2021-04-23 | 2021-05-28 | 广州市诺以德医疗科技发展有限公司 | Holographic fixed parallax stereoscopic vision degree quantizing device |
| CN112857756B (en) * | 2021-04-23 | 2021-08-06 | 广州市诺以德医疗科技发展有限公司 | Holographic fixed parallax stereoscopic vision degree quantizing device |
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