Large-depth-of-field integrated imaging 3D display device

Abstract

The invention provides a large-depth-of-field integrated imaging 3D display device which comprises a projector, a polaroid, a polarization converter, a quarter-wave plate and a geometric phase lens array. The projector is used for alternately projecting two different micro-image arrays, the polaroid is used for filtering incident light into linearly polarized light, the polarization directions of the two micro-image arrays are controlled through voltage switching of the polarization converter, and the polarization directions of the two micro-image arrays are orthogonal. The time interval of alternately projecting the two different micro-image arrays by the projector is smaller than or equal to the persistence of vision of human eyes and is the same as the voltage switching time interval of the polarization converter, and the two micro-image arrays are switched synchronously. Two linearly polarized lights with orthogonal polarization directions pass through the quarter-wave plate and then are converted into left-handed or right-handed circularly polarized lights, the geometric phase lens array presents different focal lengths for the two circularly polarized lights with different polarization directions, and 3D images are reproduced at two depth planes by using a time division multiplexing method. And a large-depth-of-field integrated imaging 3D display effect is realized.

Description

1. Technical Field

[0001] The present invention relates to the field of 3D display technology, and in particular to a 3D display device with large depth of field integrated imaging. 2. Background Technology

[0002] Integrated imaging 3D display technology is based on the principle of reversible optical path. It uses a microlens array to record the object space scene and reproduce the 3D image of the space scene. It has the advantages of continuous viewpoints, full parallax, natural depth perception, full color and real-time display. Depth of field is one of the important performance parameters of integrated imaging 3D display. It refers to the thickness of the clear 3D image near the central depth plane, that is, the distance between the front and back edges of the 3D image. The greater the depth of field, the stronger the stereoscopic feeling obtained by the viewer.

[0003] Existing integrated imaging 3D display technologies mostly use the method of creating multiple central depth planes to enhance the depth of field of 3D images. For example, multiple microlens arrays are used to form different distances between them and the microimage array to obtain multiple central depth planes, but the system structure is relatively complex. Using a semi-transparent and semi-reflective mirror to splice the central depth planes of two sets of integrated imaging 3D displays can also enhance the depth of field, but this method will make the system volume too large. III. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a large depth of field integrated imaging 3D display device, including a projector, a polarizer, a polarization converter, a quarter wave plate and a geometric phase lens array.

[0005] The projector is used for alternately projecting two different micro-image arrays.

[0006] The polarizer is used to filter incident light into linearly polarized light.

[0007] The polarization converter is used to control the polarization direction of incident linear polarized light by sequentially powering on or off.

[0008] Furthermore, the time interval for the projector to alternately project the two micro-image arrays is less than or equal to the visual persistence time of human eyes.

[0009] Furthermore, the time interval for the projector to alternately project the two micro-image arrays is the same as the voltage switching time interval of the polarization converter, and the two are switched synchronously.

[0010] The quarter wave plate is used to convert linearly polarized light into circularly polarized light.

[0011] The geometric phase lens array is used to modulate light to reproduce 3D images. When the incident light is left-handed circularly polarized light, the focal length is -f, the light beam is diverged, and exhibits the properties of a concave lens; when the incident light is right-handed circularly polarized light, the focal length is +f, the light beam is focused, and exhibits the properties of a convex lens.

[0012] The working principle of the large depth of field integrated imaging 3D display device is as follows: in the T1 time period, the projector displays the micro-image array I; the light emitted by the micro-image array I is filtered by the polarizer to obtain linear polarized light with a polarization direction of I; the polarization converter is powered on, and the linear polarized light with a polarization direction of I remains unchanged after passing through the polarization converter, and becomes left-handed circularly polarized light after passing through the quarter-wave plate, and is imaged with a focal length of -f after passing through the geometric phase lens array, so as to reproduce the 3D image I, and the depth of field is the sum of the distance from the front edge depth plane I to the center depth plane I and the distance from the center depth plane I to the rear edge depth plane I.

[0013] During time period T2, the projector displays micro-image array II; the light emitted by micro-image array II is filtered by the polarizer to obtain linear polarized light with polarization direction I; the polarization converter is powered off, and the linear polarized light with polarization direction I is converted into linear polarized light with polarization direction II after passing through the polarization converter, and then converted into right-handed circularly polarized light after passing through the quarter-wave plate, and then imaged with focal length +f after passing through the geometric phase lens array to reproduce the 3D image II, and the depth of field is the sum of the distance from the front edge depth plane II to the center depth plane II and the distance from the center depth plane II to the rear edge depth plane II.

[0014] After passing through the geometric phase lens array, the micro-image array I and the micro-image array II reproduce two central depth planes with focal lengths -f and +f, respectively, and image at different depths from the viewer. During the visual persistence time of the human eye, the viewer can simultaneously view 3D images of different depths, and the overall depth of field is increased. The polarization directions I and II are orthogonal. IV. Description of the drawings

[0015] The aforementioned aspects and advantages of the present invention will be further clarified and easily understood from the following detailed description in conjunction with the accompanying drawings and embodiments.

[0016] Attached Figure 1 It is a structural schematic diagram of a large depth of field integrated imaging 3D display device provided by an embodiment of the present invention.

[0017] Attached Figure 2 It is a schematic diagram of generating a 3D image I of a 3D display device with large depth of field integrated imaging provided by an embodiment of the present invention.

[0018] Attached Figure 3It is a schematic diagram of generating a 3D image II of a 3D display device with large depth of field integrated imaging provided by an embodiment of the present invention.

[0019] The diagram numbers of the above drawings are: 1 projector, 2 polarizer, 3 polarization converter, 4 quarter wave plate, 5 geometric phase lens array, 601 micro image array I, 602 micro image array II, 701 center depth plane I, 702 center depth plane II, 801 front edge depth plane I, 802 front edge depth plane II, 901 rear edge depth plane I, 902 rear edge depth plane II, 1001 3D image I, 1002 3D image II, 11 human eye.

[0020] It should be understood that the above drawings are only schematic and are not drawn to scale. V. Specific implementation methods

[0021] The following is a detailed description of an embodiment of a large depth of field integrated imaging 3D display device proposed by the present invention, and further describes the present invention. The following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Persons skilled in the art in this field may make some non-essential improvements and adjustments to the present invention based on the above invention content, which still fall within the scope of protection of the present invention.

[0022] Figure 1 A large depth of field integrated imaging 3D display device provided in an embodiment of the present invention comprises a projector 1, a polarizer 2, a polarization converter 3, a quarter wave plate 4 and a geometric phase lens array 5.

[0023] The projector 1 is used to alternately project the micro-image array I 601 and the micro-image array II 602, as shown in the attached Figure 2 and attached Figure 3 In one embodiment, the resolution of the projector 1 is 1280×720 pixels.

[0024] The polarizer 2 is used to filter the incident light into linear polarized light. The light emitted by the micro image array I 601 and the micro image array II 602 is filtered by the polarizer 2 to obtain linear polarized light with polarization direction I.

[0025] The polarization converter 3 is used to control the polarization direction of the incident linear polarized light by powering on or off in a timed manner, that is, to control the polarization direction of the micro image array I 601 and the micro image array II 602. When power is applied between the upper and lower transparent electrodes of the polarization converter 3, the polarization direction of the incident linear polarized light with a polarization direction of I remains unchanged after passing through the polarization converter 3; when power is removed between the upper and lower transparent electrodes of the polarization converter 3, the incident linear polarized light with a polarization direction of I becomes a linear polarized light with a polarization direction of II after passing through the polarization converter 3.

[0026] The time interval of the projector 1 alternately projecting the micro-image array I 601 and the micro-image array II 602 is less than or equal to the visual persistence time of the human eye. The visual persistence time of the human eye is a time set according to the visual inertia of the human eye. Visual inertia is an important characteristic of the human eye, that is, after the image is formed on the retina of the human eye, the human eye will visually maintain the image formed on the retina for a limited time. This limited time, namely the visual persistence time of the human eye, is about 50ms to 200ms. In one embodiment, the time interval is 16.67ms.

[0027] The time interval for the projector 1 to alternately project the micro image array I 601 and the micro image array II 602 is the same as the time interval for the voltage switching of the polarization converter 3, and the two are switched synchronously. In one embodiment, the time interval for the voltage switching of the polarization converter 3 is 16.67ms.

[0028] The quarter wave plate 4 is used to convert the linear polarized light with polarization direction I corresponding to the micro image array I 601 into left-handed circularly polarized light, and convert the linear polarized light with polarization direction II corresponding to the micro image array II 602 into right-handed circularly polarized light.

[0029] The geometric phase lens array 5 is used to modulate light to reproduce 3D images. When the incident light is left-handed circularly polarized light, the focal length is -f, the light beam is diverged, and it exhibits the properties of a concave lens; when the incident light is right-handed circularly polarized light, the focal length is +f, the light beam is focused, and it exhibits the properties of a convex lens. When the micro-image array I 601 with a polarization direction of left-handed circularly polarized light passes through the geometric phase lens array 5, it is imaged with a focal length of -f = -20.00 mm, and a 3D image I 1001 is reproduced. The depth of field is the distance l from the front edge depth plane I 801 to the center depth plane I 701. r = 44.92 mm Distance l from the center depth plane I 701 to the rear edge depth plane I 901 f =The sum of 40.74mm is 85.66mm.

[0030] When the micro image array II 602 with right circular polarized light passes through the geometric phase lens array 5, it is imaged with a focal length of +f=+20.00mm to reproduce a 3D image II 1002, and the depth of field is the distance l' from the front edge depth plane II 802 to the center depth plane II 702. r = 6.15 mm Distance l' from the center depth plane II 702 to the rear edge depth plane II 902 f =The sum of 6.06mm is 12.21mm.

[0031] l r , lf , l' r With l' f The calculation formulas are:

[0032]

[0033] Where α = 0.00029 rad is the limit angle of human eye resolution, d1 = 880.00 mm is the distance from the center depth plane I 701 to the human eye 11, d2 = 930.98 mm is the distance from the center depth plane II 702 to the human eye 11, and p ape =25.00mm is the aperture stop size of projector 1, a pro =1050.00 mm is the distance from the projector 1 to the micro-image array I 601 or the micro-image array II 602 , and g=15.00 mm is the distance from the geometric phase lens array 5 to the micro-image array I 601 or the micro-image array II 602 .

[0034] The specific implementation process of the large depth of field integrated imaging 3D display device is as follows:

[0035] In the T1 time period, the projector 1 projects the micro-image array I 601; the light emitted by the micro-image array I 601 is filtered by the polarizer 2 to obtain linear polarized light with a polarization direction of I; the polarization converter 3 is powered on, and the linear polarized light with a polarization direction of I remains unchanged after passing through the polarization converter 3, and becomes left-handed circularly polarized light after passing through the quarter-wave plate 4, and is imaged with a focal length of -f after passing through the geometric phase lens array 5, thereby reproducing a 3D image I 1001, and the depth of field is the distance l from the front edge depth plane I801 to the center depth plane I 701 r = 44.92 mm Distance l from the center depth plane I 701 to the rear edge depth plane I901 f =The sum of 40.74mm is 85.66mm.

[0036] During time period T2, the projector 1 projects micro-image array II 602; the light emitted by micro-image array II 602 is filtered by the polarizer 2 to obtain linear polarized light with polarization direction I; the polarization converter 3 is powered off, and the linear polarized light with polarization direction I is converted into linear polarized light with polarization direction II after passing through the polarization converter 3, and then converted into right-handed circular polarized light after passing through the quarter-wave plate 4, and then formed into an image with focal length +f after passing through the geometric phase lens array 5, thereby reproducing a 3D image II 1002, and the depth of field is the distance l' from the front edge depth plane II 802 to the center depth plane II 702. r = 6.15 mm Distance l' from the center depth plane II 702 to the rear edge depth plane II 902 f=6.06mm, which is 12.21mm. The total depth of field of the integrated imaging 3D display device is 97.87mm.

[0037] The present invention realizes the independent display of two groups of 3D images at different depth positions by using the time division multiplexing method, realizes the integrated imaging 3D display effect with a large depth of field, only needs one microlens array to create two central depth planes, has a simple structure and is easy to implement.

[0038] The above disclosure is only a preferred embodiment of the present invention, which cannot be used to limit the scope of protection of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A 3D display device with large depth of field integrated imaging, characterized in that: Includes projectors, polarizers, polarization converters, quarter-wave plates, and geometric phase lens arrays; The projector is used to alternately project two different micro-image arrays; The polarizer is used to filter the incident light into linearly polarized light; The polarization converter is used to control the polarization direction of incident linear polarized light by sequentially powering on or off; The quarter wave plate is used to convert linearly polarized light into circularly polarized light; The geometric phase lens array is used to modulate light to reproduce a 3D image. When the incident light is left-handed circularly polarized light, the focal length is -f, the light beam is diverged, and exhibits the properties of a concave lens; when the incident light is right-handed circularly polarized light, the focal length is +f, the light beam is focused, and exhibits the properties of a convex lens. The time interval for the projector to alternately project two different micro-image arrays is less than or equal to the visual persistence time of human eyes, is the same as the voltage switching time interval of the polarization converter, and the two are switched synchronously.

2. The large depth of field integrated imaging 3D display device according to claim 1, characterized in that: The polarization converter is powered on or off by timing control; in the T1 time period, the projector displays the micro-image array I, the light emitted by the micro-image array I is filtered by the polarizer to obtain linear polarized light with a polarization direction of I, the polarization converter is powered on, the linear polarized light with a polarization direction of I remains unchanged after passing through the polarization converter, becomes left-handed circularly polarized light after passing through the quarter-wave plate, and is imaged with a focal length of -f after passing through the geometric phase lens array, reproducing a 3D image I, and the depth of field is the sum of the distance from the front edge depth plane I to the center depth plane I and the distance from the center depth plane I to the rear edge depth plane I; In time period T2, the projector displays micro-image array II, and the light emitted by micro-image array II is filtered by the polarizer to obtain linear polarized light with polarization direction I. The polarization converter is powered off, and the linear polarized light with polarization direction I is converted into linear polarized light with polarization direction II after passing through the polarization converter, and then converted into right-handed circularly polarized light after passing through the quarter-wave plate. After passing through the geometric phase lens array, the image is formed with focal length +f to reproduce the 3D image II, and the depth of field is the sum of the distance from the front edge depth plane II to the center depth plane II and the distance from the center depth plane II to the rear edge depth plane II. During the visual persistence time of the human eye, the viewer can simultaneously view 3D images of different depths, and the overall depth of field is increased. The polarization directions I and II are orthogonal.

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