Three-dimensional display module based on multi-focal microlens array

Abstract

The present application relates to the technical field of three-dimensional, more particularly, to a kind of three-dimensional display module based on multi-focal microlens array, the three-dimensional display module includes microlens array, display device, control unit and unidirectional scatterer.Wherein, microlens array includes the multiple microlens groups of being respectively arranged with different focal lengths and being mutually interpenetrated, different microlens group respectively on display device corresponding pixel group is formed by different corresponding pixel;Different pixel group-microlens group structure can be mutually identified between design, each pixel group-microlens group structure respectively implements integrated imaging display.By sacrificing the corresponding pixel view point density of each microlens in binocular connection direction, combined with unidirectional scattering, compared with traditional integrated imaging display structure, the three-dimensional display module of the present application realizes the natural focusing display of display resolution improvement and display depth extension, especially suitable for in the field of vehicle head-up display.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional image display technology, and more specifically, to a three-dimensional display module based on a multi-focal-length microlens array. Background Technology

[0002] Traditional 2D displays lose depth information of the displayed scene, making 3D displays, which can express spatial depth information, increasingly important. To overcome the visual fatigue caused by inherent focusing and convergence conflicts in traditional stereoscopic 3D display technologies, light field display technology, which achieves comfortable visual experience, is currently a cutting-edge hot topic in the field of 3D displays. Integrated imaging uses microlens arrays as light modulation devices, with pixels on the display device corresponding to different microlenses displaying corresponding image elements. Each image element projects a beam of light through mirrored microlenses, and through the spatial superposition of beams from different image elements, a naturally focused spatial light point distribution is formed, achieving light field display. The thin and light structure of the microlens array, and its compatibility with traditional 2D display devices, make integrated imaging one of the main light field display technologies currently available.

[0003] In integrated imaging displays, the light projected by a pixel corresponding to any microlens is guided by the microlens to different pixel viewpoints. To achieve natural focusing, the pixel viewpoints corresponding to each microlens need to cover the observer's two pupils, and the spacing between adjacent pixel viewpoints corresponding to the same microlens must be smaller than the diameter of the observer's pupils. Therefore, a large number of corresponding pixels are needed for each microlens to project small-pitch pixel viewpoints covering the observer's two pupils. For example, covering a 60mm × 30mm area including both pupils requires 800 pixel viewpoints with a spacing of 1.5mm × 1.5mm. In fact, in integrated imaging displays, the more pixel viewpoints there are, the lower the display resolution. Furthermore, integrated imaging has a limited depth of field, which cannot meet the needs of applications requiring a large depth of field, such as the simultaneous display requirements of driving data at close range and navigation icons at distant range in automotive head-up displays. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a three-dimensional display module based on a multi-focal-length microlens array. This invention utilizes multiple interleaved microlens groups with different focal lengths to construct a microlens array, designs mutual recognizability between different pixel group-microlens group structures, guides different pixel groups to perform integrated imaging display on their respective corresponding depth planes through their corresponding microlens groups, and further improves display resolution by introducing sub-pixel viewpoints and / or unidirectional scatterers.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: a three-dimensional display module based on a multi-focal-length microlens array, comprising:

[0006] A microlens array is composed of a two-dimensional arrangement of microlenses, wherein microlenses are grouped together at intervals of M-1 microlenses along a one-dimensional x-direction. Each of the M microlens groups is endowed with different orthogonal characteristics. Each microlens group only allows light with corresponding orthogonal characteristics to be modulated and emitted, and microlenses belonging to different groups have different focal lengths, wherein M≧2.

[0007] The display device includes multiple pixels or multiple sub-pixels, which are placed corresponding to the microlens array to form a display device-microlens array structure.

[0008] In the display device-microlens array structure, each microlens of any microlens group corresponds to a pixel or sub-pixel on the display device, forming a corresponding pixel group or sub-pixel group of the microlens group. The emitted light characteristics of each pixel group or sub-pixel group are set to be consistent with the orthogonal characteristics of the corresponding microlens group, and the corresponding pixels or sub-pixels of adjacent microlenses in the same group belong to different adjacent regions in the corresponding pixel group or sub-pixel group.

[0009] The control unit is connected to the display device and can control the light information loaded on each pixel or sub-pixel, which is the projected light information of the scene to be displayed along the line connecting the pixel or sub-pixel and the corresponding microlens. The connection between the control unit and the display device can be a wireless communication connection or a wired communication connection.

[0010] In this configuration, each pixel or sub-pixel projects a light beam onto the observation surface of the eyebox via a corresponding microlens. Furthermore, along at least one direction, the pixel-to-viewpoint spacing or sub-pixel-to-viewpoint spacing corresponding to each microlens is smaller than the observer's pupil diameter. This ensures that, for any object to be displayed, the pupil within the eyebox can receive at least two light beams passing through that object.

[0011] Wherein, along at least one direction, the pixel viewpoint spacing or sub-pixel viewpoint spacing corresponding to the microlens refers to the distance between the projection points of adjacent pixels or adjacent sub-pixels corresponding to the same microlens along that direction, when the light beams projected by the microlens are placed on the observation surface of the eyebox.

[0012] In one specific implementation, the 3D display module further includes a pupil tracking unit connected to the control unit. This pupil tracking unit tracks and locates the observer's pupil position in real time and determines the corresponding pixel or sub-pixel for each microlens based on the pupil position, ensuring that the eye box tracks and covers the observer's pupil. The connection between the control unit and the pupil tracking unit can be either a wireless communication connection or a wired communication connection.

[0013] In one specific implementation, the three-dimensional display module further includes a one-way scatterer attached to the microlens array and scattering incident light in the x-direction;

[0014] The one-way scatterer is configured such that: after a light beam from any corresponding pixel or sub-pixel is scattered by the one-way scatterer, the x-direction dimension of the effective light distribution area on the observation surface where the eyebox is located, where the light intensity is greater than 10% of its extreme intensity, is smaller than the interpupillary distance of the observer.

[0015] In one specific implementation, when the 3D display module includes a one-way diffuser, it also includes a pupil tracking unit connected to the control unit. This pupil tracking unit tracks and locates the observer's pupil position in real time. For each pixel or sub-pixel where the effective light distribution area intersects with the observer's pupil, the control unit can control the loading of information as: the projection light information of the scene to be displayed along the line connecting the observer's pupil and the corresponding microlens of that pixel or sub-pixel. The connection between the control unit and the pupil tracking unit can be either a wireless communication connection or a wired communication connection.

[0016] In one specific implementation, when the 3D display module includes a one-way diffuser, it also includes a pupil tracking unit connected to the control unit. This pupil tracking unit tracks and locates the observer's pupil position in real time, determining the corresponding pixels for each microlens based on the pupil position to ensure the eye box's tracking coverage of the observer's pupil. The connection between the control unit and the pupil tracking unit can be either a wireless or wired communication connection.

[0017] In one specific implementation, each microlens is attached with an aperture number consistent with the number of sub-pixel types, which respectively allow the colored light projected by different types of sub-pixels to pass through.

[0018] In one specific implementation, the orthogonality characteristic is M mutually orthogonal polarization states;

[0019] The M pixel groups corresponding to the M microlens groups are groups of pixels spaced 1 pixel apart along the x-direction. The emitted light from the M pixel groups are the M polarized light states, where M = 2.

[0020] In one specific implementation, the orthogonal characteristics of each pixel or sub-pixel and each microlens are achieved through their respective attached polarizers.

[0021] In one specific implementation, the 3D display module further includes a timing control device connected to the control unit. The orthogonal characteristic is a timing characteristic that is activated at M time points. The timing control device can sequentially select the light-transmitting apertures of M microlens groups at M time points in each time period.

[0022] Among them, the M pixel groups or sub-pixel groups corresponding to the M microlens groups contain the same pixels or sub-pixels, but are activated at different time points in each time period under the control of the control unit, so as to correspond to the M microlens groups at different time points respectively.

[0023] In one specific implementation, the orthogonality of each microlens is controlled by a timing control device controlled by a control unit to controllably select the aperture of each microlens.

[0024] In one specific implementation, the orthogonal characteristic is a pointing characteristic, where the light emitted from each pixel or sub-pixel points to the corresponding microlens.

[0025] In one specific implementation, the three-dimensional display module further includes a vector control device composed of a vector control unit, which corresponds one-to-one with each pixel or sub-pixel of the display device and is used to control the projection direction of the light emitted from the corresponding pixel or sub-pixel.

[0026] In one specific implementation, the orthogonal characteristic is a color characteristic of M different wavelengths; the M microlens groups correspond to M sub-pixel groups, which are composed of sub-pixels spaced (M-1) sub-pixels along the x-direction, and the M sub-pixel groups emit the M different wavelength colors of light respectively.

[0027] In one specific implementation, the orthogonality of each sub-pixel and each microlens is achieved through their respective attached color filters.

[0028] In one specific implementation, the orthogonal characteristic is a combination of at least two of the following: mutually orthogonal polarization states, timing characteristics, pointing characteristics, and color characteristics.

[0029] In one specific implementation, the microlens is a micro / nano structure with lens function.

[0030] In one specific embodiment, the spacing between the microlenses along the x-direction and their perpendicular direction are different. In another specific embodiment, the microlens has polarization state sensitivity characteristics, and the microlens exhibits T′ focal lengths for each of T′ polarization states, where T′≧1.

[0031] Among them, the pixel group corresponding to the same microlens group is divided into T′ pixel subgroups, and each of the T′ pixel subgroups emits light in T′ polarized states.

[0032] In one specific implementation, the 3D display module further includes a projection device positioned in front of the microlens array along the light transmission direction to image the display device-microlens array structure.

[0033] The projection device is a single optical element or a combination of multiple optical elements.

[0034] In one specific implementation, the 3D display module further includes a deflection device positioned in the light transmission path to guide the transmission direction of the incident light.

[0035] The deflection device is a single optical element or a combination of multiple optical elements.

[0036] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention increases the number of display depth planes without affecting display resolution by sacrificing the pixel viewpoint density corresponding to each microlens along the binocular line or by utilizing temporal multiplexing. Furthermore, it introduces sub-pixel viewpoints and / or unidirectional scatterers to reduce the number of viewpoints required to cover both pupils of the observer. Ultimately, based on a thin and light structure, and provided that the spacing between the pixel viewpoints or sub-pixel viewpoints corresponding to each microlens along at least one dimension is smaller than the diameter of the observer's pupil, it achieves a light field display with improved display resolution and integrated imaging display across multiple depth planes. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the M=2 orthogonal characteristic setting rules of the display device and microlens array in Embodiment 1 of the present invention.

[0038] Figure 2 This is a schematic diagram of different pixel groups being projected onto different depth surfaces by their respective corresponding microlens groups in Embodiment 1 of the present invention.

[0039] Figure 3 This is a schematic diagram of beam guidance in the xz plane of a pixel group-microlens group structure in Embodiment 1 of the present invention.

[0040] Figure 4 This is a schematic diagram of beam guidance in the yz plane of a pixel group-microlens group structure in Embodiment 1 of the present invention.

[0041] Figure 5 This is a schematic diagram illustrating an example of the asymmetric distribution of the pixel viewpoint spacing corresponding to a microlens in Embodiment 1 of the present invention.

[0042] Figure 6 This is a schematic diagram illustrating an effective light distribution area after the pixel-projected light passes through a one-way scatterer in Embodiment 1 of the present invention.

[0043] Figure 7 This is a schematic diagram illustrating another effective light distribution area example after the pixel-projected light passes through a one-way scatterer in Embodiment 1 of the present invention.

[0044] Figure 8 This is a schematic diagram illustrating an example of adjacent microlenses in the y-direction being misaligned along the x-direction in Embodiment 1 of the present invention.

[0045] Figure 9 This is a schematic diagram of the optical structure of a three-dimensional display module in Embodiment 1 of the present invention, which uses timing characteristics as orthogonal characteristics.

[0046] Figure 10 This is a schematic diagram of an example optical structure of a three-dimensional display module in Embodiment 1 of the present invention, which uses pointing characteristics as orthogonal characteristics.

[0047] Figure 11 This is a schematic diagram illustrating an example of the optical structure of a three-dimensional display module incorporating a projection device, as shown in Embodiment 2 of the present invention.

[0048] Figure 12 This is an example of a three-dimensional display module in Embodiment 2 of the present invention, which uses projection devices that present different focal lengths for light with different orthogonal characteristics.

[0049] Figure 13 This is a schematic diagram of another three-dimensional display module example in Embodiment 2 of the present invention, which uses a projection device that presents different focal lengths for light with different orthogonal characteristics.

[0050] Figure 14 This is a schematic diagram illustrating an example of the optical structure of a three-dimensional display module in Embodiment 2 of the present invention, which incorporates a deflection device. Detailed Implementation

[0051] The accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. The dimensions of the optical components and their relative distances shown in the drawings are also merely illustrative and do not limit the actual dimensions of the optical components or their relative distances in the actual optical structure. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. This invention achieves greater depth of field and higher resolution light field display by designing mutually identifiable image array-microlens array structures for integrated imaging display on multiple depth planes, combined with a one-way scatterer.

[0052] Example 1

[0053] Taking M = 2 mutually orthogonal polarization states as an example, the orthogonal characteristic is illustrated by... Figure 1 The orthogonal characteristic configuration of the display device 20 and the microlens array 10 is shown. Here, M = 2 polarization states, which can be linearly polarized states with mutually perpendicular polarization directions, or left-handed and right-handed polarization, represented by "·" and "-" respectively. Figure 1 The image shows only a portion of the pixels and microlenses. Taking the x-direction as the row direction, along this row direction, pixels in the display device 20 are grouped with a spacing of M-1 = 1 pixels. Specifically, pixels ..., ..., P... ij P ij+2P ij+4 P ij+6 P ij+8 P ij+10 ..., ..., P i+1j P i+1j+2 P i+1j+4 P i+1j+6 P i+1j+8 P i+1j+10 ..., ..., P i+2j P i+2j+2 P i+2j+4 P i+2j+6 P i+2j+8 P i+2j+10 ...grouped together, emitting "·" light, this is called a "·" image array; pixels..., ..., P ij+1 P ij+3 P ij+5 P ij+7 P ij+9 P ij+11 ..., ..., P i+1j+1 P i+1j+3 P i+1j+5 P i+1j+7 P i+1j+9 P i+1j+11 ..., ..., P i+2j+1 P i+2j+3 P i+2j+5 P i+2j+7 P i+2j+9 P i+2j+11 Grouped together, ..., ..., they emit "-" light and are called "-" pixel groups. Figure 1 In the diagram, the y-direction is shown as the column direction, and the emitted light from pixels in the same column has the same orthogonal characteristics. For clarity, only one pixel in the same column is labeled with the orthogonal characteristics corresponding to that column's pixels. Correspondingly, along the x-direction, in the microlens array 10, microlenses spaced M-1 = 1 apart are grouped, allowing only "·" light and "-" light to be modulated and emitted, respectively, and are referred to as the "·" microlens group and the "-" microlens group. Specifically, the microlenses are...,..., L... ij L ij+2 、…,…、L i+1j L i+1j+2 ..., ... form a "·" microlens group; microlenses ..., ..., L ij+1 L ij+3 、…,…、L i+1j+1 L i+1j+3 ..., ... form a "-" microlens group. For clarity of illustration, Figure 1Only a portion of the pixels and microlenses are shown; the remaining pixels and microlenses can be clearly identified based on their arrangement. The names of the microlenses and pixels are shown, with the first letter of the subscript indicating the row number and the second letter indicating the column number. Here, the "·" microlens group only allows the "·" light to be modulated and emitted, meaning it does not allow the "-" light to be modulated and emitted. It should be noted that the "·" microlens group not allowing the "-" light to be modulated and emitted does not mean that it completely blocks the "-" light; rather, it means that the noise caused by the transmission rate of the "-" light through the "·" microlens group is within the range of the target display noise. Similarly, the "-" microlens group only allowing the "-" light to be modulated and emitted does not mean that it completely blocks the "·" light; rather, it means that the noise caused by the transmission rate of the "·" light through the "-" microlens group is within the range of the target display noise. In this patent, the "not allowed" emission of incident light with non-corresponding orthogonal characteristics by a microlens with a certain orthogonal characteristic is understood based on this criterion. Therefore, the "-" pixel group-"-" microlens group structure and the "·" pixel group-"·" microlens group structure can recognize each other, and they independently perform integrated imaging of the three-dimensional light field display. Different groups of microlens groups are set, each with a different focal length, for example... Figure 1 In the "·" microlens group, each microlens has a focal length of f1, and in the "-" microlens group, each microlens has a focal length of f2. Therefore, these M = 2 image groups will be projected onto different depth planes by their respective corresponding microlens groups. Specifically, as follows... Figure 2 As shown, the "-" pixel group is projected onto the - pixel image plane by the corresponding "-" microlens group; the "·" pixel group is projected onto the · pixel image plane by the corresponding "·" microlens group. That is to say, the M=2 pixel group can be equivalently placed on different depth planes (· pixel image plane and - pixel image plane) and displayed with respect to their respective microlens groups. Figure 1 and Figure 2 In this patent, each microlens can be a traditional optical glass lens, and its corresponding orthogonal characteristics can be implemented by an attached polarizer; it can also be a micro / nano structure, such as a superlens, and its corresponding orthogonal characteristics can be implemented by an attached polarizer, or by utilizing the polarization characteristics imparted during the fabrication process of the micro / nano structure itself (different focal lengths for incident light with different polarization characteristics). In this patent, if the corresponding orthogonal characteristics of each microlens need to be realized by a corresponding functional device, it is assumed that the functional device is included in the microlens and does not need to be shown separately.

[0054] Figure 3 Taking the "·" pixel group - "·" microlens group structure as an example, this explains the display principle of a single pixel group - microlens group structure along the x-axis (row direction). For clarity of illustration, Figure 3Only a few rows of pixels and two rows of microlenses are shown for illustration. Here, the pixels of display device 20 are evenly spaced p along the x-direction. x Taking the arrangement as an example, the pixel spacing in the x-direction of each pixel group is Mp. x ,like Figure 3 The x-axis pixel spacing Mp of the "·" pixel group shown in the figure x =2p x Similarly, the microlenses of the microlens array 10 are equally spaced b along the x-direction. x Taking the arrangement as an example, the x-axis microlens spacing of each microlens group is Mb. x ,like Figure 3 The x-axis microlens spacing Mb of the microlens group shown in the figure is... x =2b x Based on the mutual recognition characteristics between different pixel group-microlens group structures, the light pairs projected by the "·" pixel group are not considered here. Figure 3 The transmission of the "-" microlens group (not shown) Figure 3 In the diagram, the region between adjacent microlenses in the x-direction of the "·" microlens group is shown as non-transparent. In actual 3D display modules, crosstalk noise caused by the transmission of light from the "·" pixel group to the "-" microlens group and vice versa needs to be considered. Therefore, pixel P... i+4j The emitted light passes through the corresponding microlens L ij Guided pixel viewpoint 16, pixel P i+4j+2 The emitted light passes through the corresponding microlens L ij Guided pixel viewpoint 15, pixel P i+4j+4 The emitted light passes through the corresponding microlens L ij Guided pixel viewpoint 14, pixel P i+4j+6 The emitted light passes through the corresponding microlens L ij Guided to pixel viewpoint 13, pixel P i+4j+8 The emitted light passes through the corresponding microlens L ij Guided pixel viewpoint 12, pixel P i+4j+10 The emitted light passes through the corresponding microlens L ij Guided pixel viewpoint 11. That is, microlens L ij The light beam emitted from a corresponding pixel is guided to different pixel viewpoints by this microlens. The x-axis spacing between adjacent pixel viewpoints is:

[0055] e x / (M×p x )=(D e -D b ) / D b → e x = (M×p x (D) e -D b ) / D b (1),

[0056] Where D e D is the distance between the view plane where the pixel viewpoint is located and the pixel plane. b This is the distance between the plane containing the microlens and the pixel plane. In this "·" pixel group - "·" microlens group structure, the regions of pixels corresponding to adjacent microlenses are also arranged adjacently. Each pixel is imaged onto its corresponding image plane through its corresponding microlens, and the "·" pixel group is imaged onto the "·" pixel image plane through the "·" microlens group. Therefore, this "·" pixel group - "·" microlens group structure uses the "·" pixel image plane as the equivalent display plane to implement integrated imaging display. Along the x-direction, Figure 3 m corresponding to a single microlens x Taking 6 pixels as an example, this m x Other values ​​are possible. Figure 3 The geometric relationship between the x-axis pixel spacing and the microlens spacing is set to satisfy:

[0057] (D e -D b ) / D e =M×b x / (m x ×M×p x (2).

[0058] Under this geometric relationship, the pixel viewpoints formed by different microlenses coincide with each other. Figure 3 m shown x = 6 pixels forming an m x =6 image viewpoints, i.e. Figure 3 Pixel viewpoints 11, 12, 13, 14, 15, and 16 in the image are also image viewpoints. A corresponding two-dimensional image can be received at any of these image viewpoints. Along the x-axis, the resolution of this two-dimensional image is DRes. x and display device resolution SRes x The relationship is:

[0059] DRes x =SRes x / (M×m x (3).

[0060] Figure 3 The x-direction viewing area constructed from each pixel viewpoint, forming a "·" pixel group-"·" microlens group structure, has the following dimensions:

[0061] W x =m x ×e x =m x ×(M×p x (D) e -D b) / D b (4).

[0062] For this "·" pixel group - "·" microlens group structure Figure 4 The diagram illustrates its display principle along the y-axis (column direction). Compared to the x-axis, there are no inter-pixel gaps between the pixels corresponding to each microlens along the y-axis, based on... Figure 4 The geometric relationship shown,

[0063] e y / p y =(D e -D b ) / D b → e y =p y ×(D e -D b ) / D b (5),

[0064] (D e -D b ) / D e =b y / (m y ×p y (6),

[0065] DRes y =SRes y / m y (7)

[0066] W y =m y ×e y =m y ×p y ×(D e -D b ) / D b (8).

[0067] Where p y m is the pixel pitch of the display device 20 along the y-axis. y e represents the number of pixels corresponding to a single microlens along the y-direction. y b is the pixel viewpoint spacing along the y-axis. y DRes represents the spacing between microlenses in the same group along the y-axis. y and SRes y For the y-axis resolution (i.e., display resolution) of the projected two-dimensional image and the y-axis resolution of the display device 20, W y This refers to the y-axis viewport size. The values ​​of the parameters involved in this patent may not be equal along the x and y directions.

[0068] Comparing formulas (1) and (5), we can see that e x / e y = (M×p x ) / p y For example, in p x =p y In this case, e x =Me y In other words, in the same pixel group-microlens group structure of this patent, the pixel viewpoint corresponding to the same microlens may not be equal along different directions, such as... Figure 5 The example shows a portion of the pixel viewpoints corresponding to the same microlens. Of course, in display device 20, p... x ≠p y Within the same pixel group-microlens group structure, while ensuring e y <D p In the case of e x >D p This also ensures that for a given display point, at least two light beams are incident on the same pupil of the observer; driven by binocular parallax coupling, when the overlapping light distribution of at least two light beams at any display point can draw the observer's eye focus, natural-focusing 3D display can be achieved. Wherein, D p The diameter of the observer's pupil. The control unit 30 controls the loading of light information onto each pixel, optimally selecting the optical center of the corresponding microlens along the line connecting the pixel and the point on the corresponding microlens, to project the light information of the scene to be displayed. If the goal is binocular display, this display process requires a viewing area size W along the x-axis. x Sufficient to cover both eyes of the observer. The x-direction described in this patent is optimally the direction connecting the observer's eyes. Each pixel viewpoint within this viewing area can receive the corresponding two-dimensional image of the field to be displayed. This viewing area is the eyebox of the pixel group-microlens group structure, and its surface is the observation surface. The y-direction is usually chosen to be perpendicular to the x-direction, but it can also be non-perpendicular. Compared to traditional integrated imaging displays, in the integrated imaging display implemented by this patent with a pixel group-microlens group structure, the pixel spacing corresponding to the same microlens along the x-direction may be greater than the observer's pupil diameter D. p However, it is necessary that, at least in one direction, the pixel spacing between corresponding microlenses is not less than the observer's pupil diameter D. p In fact, if the pixel spacing corresponding to the same microlens is not less than the observer's pupil diameter D in all directions... p The three-dimensional display module can also be displayed based on stereoscopic technology.

[0069] Figures 2 to 3 The three-dimensional display module structure shown is based on formulas (2) and (6), and the pixel viewpoint distribution areas corresponding to each microlens are designed to coincide perfectly to form an eyebox. Figures 2 to 3As shown, under the condition that formulas (2) and (6) hold, the specific pixels corresponding to each microlens can also change, accompanied by a translation of the corresponding eyebox position. The three-dimensional display module can introduce a pupil tracking unit 40, such as Figure 2 As shown, the system tracks and locates the observer's pupil position in real time, and determines the specific pixel corresponding to each microlens based on the pupil position to ensure that the corresponding eyebox covers the observer's pupil. Figure 3 For example, microlens L ij The corresponding pixel is P i+4j P i+4j+2 P i+4j+4 P i+4j+6 P i+4j+8 P i+4j+10 Transform into P i+4j+2 P i+4j+4 P i+4j+6 P i+4j+8 P i+4j+10 P i+4j+12 At this time, the area covered by the corresponding pixel viewpoint will shift. Simultaneously, the pixels corresponding to other microlenses will also change accordingly, with microlens L... ij+2 For example, its corresponding pixel is also determined by P. i+4j+12 P i+4j+14 ... transform into P i+4j+14 P i+4j+16 ... Here we only take the x-direction as an example; the same applies to the y-direction.

[0070] Formulas (2) and (6) above are not mandatory requirements. For example, the design scheme in traditional integrated imaging displays where the microlens spacing is consistent with the spacing of their corresponding pixel distribution areas can also be applied to the pixel group-microlens group structure of this patent. That is to say, in the same pixel group-microlens group structure, the microlens spacing and the spacing of their corresponding pixel distribution areas may not conform to formulas (2) and (6). In this case, the area where the pupil can receive at least two beams of light through each object to be displayed is the corresponding eyebox of each pixel group-microlens group structure, and a pupil tracking unit 40 can also be introduced to ensure that the eyebox tracks and covers the observer's pupil.

[0071] Figures 2 to 3This paper describes the integrated imaging display process of a pixel group-microlens group structure. Other pixel group-microlens group structures are displayed similarly. Given that the viewing areas of all pixel group-microlens group structures overlap, they are equivalent to projecting light information from different depth planes into this overlapping area based on the integrated imaging display principle. This overlapping area serves as the eyebox of the 3D display module described in this patent. When the display depth ranges at different depth planes are interconnected, continuous expansion of the depth of field can be achieved; the display depth ranges at different depth planes can also be independent, for example, in vehicle head-up displays, satisfying the application requirements of displaying driving data within a near-field depth range and navigation icons within a far-field depth range.

[0072] Figure 5 In this diagram, the pixel viewpoint spacing in the x-direction is greater than the pixel viewpoint spacing in the y-direction. The light distribution area from each pixel at each viewpoint is illustrated as a circle, meaning the light intensity distribution of the light projected by the corresponding pixel at each viewpoint is confined to that circular area. Along the x-direction, due to the larger pixel viewpoint spacing, the received display light intensity decreases significantly at certain locations. For example, at the midpoint of the line connecting two adjacent pixel viewpoints, the intensity of the light information received from those two pixels may decrease significantly, especially at point e. x >D p In some cases, this will significantly affect the display effect. To avoid this, a one-way scatterer 50, such as a holographic grating-type scattering element, is placed behind the lens array 10 to scatter the incident light beam after passing through the microlens array 10 along the x-direction. This causes the light distribution from any corresponding pixel after passing through the microlens to be broadened along the x-direction on the observation surface where the eyebox is located. The broadened light distribution from any pixel, along the x-direction on the observation surface, has a light intensity greater than 10% of the extreme intensity in the effective light distribution area size, which can be designed to be equal to e x ,like Figure 6 As shown. Figure 6 The ellipse in the example is merely an illustration and does not represent that the effective light distribution area of ​​the corresponding pixel's projected light after passing through the one-way scatterer 50 at each pixel's viewpoint must be elliptical. This interpretation also applies to the subsequent parts of this patent. For each pixel whose effective light distribution area expands along the x-direction, when the effective light distribution area corresponding to its pixel viewpoint overlaps with the observer's pupil, the light information loaded under the control of the control unit 30 can be redesigned as: the projected light information of the scene to be displayed along the line connecting a point in the overlapping area and a point on the microlens corresponding to the pixel. The point in the overlapping area is optimally taken as the point of maximum light intensity projected by the corresponding pixel within the overlapping area, and based on geometric optics, the intersection of the ray corresponding to the point of maximum light intensity and the corresponding microlens is taken as the aforementioned "point on the corresponding microlens".

[0073] Furthermore, the effective light distribution area size, where the light intensity of a beam from any pixel, along the x-axis on the observation plane is greater than 10% of the extreme intensity after being stretched, can also be designed to be greater than e. x Or larger than the observer's pupil diameter, such as Figure 7 As shown. However, to avoid significant crosstalk noise between the observer's eyes, the x-axis dimension of the effective light distribution area corresponding to each pixel needs to be smaller than the interpupillary distance of the observer. In this case, for each pixel whose effective light distribution area expands along the x-axis, when its corresponding effective light distribution area overlaps with the observer's pupil, the light information loaded under the control of the control unit 30 can also be redesigned as: the projection light information of the scene to be displayed along the line connecting a point in the overlapping area and a point on the microlens corresponding to the pixel. The point in the overlapping area is optimally taken as the point with the maximum projection light intensity of the corresponding pixel in the overlapping area, and based on geometric optics, the intersection of the light ray corresponding to the point with the maximum light intensity and the corresponding microlens is taken as the aforementioned "point on the corresponding microlens". That is to say, after introducing the one-way scatterer 50, the effective light distribution area of ​​each pixel projecting light onto the observation surface through the corresponding microlens can be larger than the diameter of the observer's pupil along the x-axis, but cannot be larger than the interpupillary distance of the observer. In this case, the number of pixels that the observer's pupil can receive can be increased, and the eyebox is also expanded along the x-axis. At this time, the 3D display module can incorporate a pupil tracking unit 40 to track and locate the observer's pupil position in real time, and determine the corresponding pixels of each microlens based on the observer's pupil position to ensure that the eye box tracks and covers the observer's pupil. Alternatively, it can update the loaded light information content of each pixel in real time based on the pupil position.

[0074] The above Figure 1 In the diagram, adjacent microlenses in the y-direction are arranged without misalignment along the x-direction. They can also be arranged with misalignment along the x-direction, such as... Figure 8 As shown. Figure 1 In the diagram, adjacent microlenses are shown arranged side-by-side without gaps. In reality, however, light-blocking intervals can also be designed between adjacent microlenses, for example, by using an aperture to block light from these intervals. The size of these light-blocking intervals affects the ratio of the microlens' aperture to the microlens spacing. A suitable choice of this ratio helps constrain the spatial light distribution pattern of the beam emitted from each pixel.

[0075] The orthogonal characteristic can also be a timing characteristic where M time points are activated respectively. In this case, the 3D display module also includes a timing control device 60 that is signal-connected to the control unit 30, such as... Figure 9 As shown. Figure 9The timing control device 60 shown is a controllable switching device, such as a liquid crystal light valve array, whose liquid crystal light valves correspond one-to-one with each microlens of the microlens array; under the control of the control unit 30, the timing control device 60 sequentially selects the light transmission apertures of M microlens groups at M time points in each time period. Figure 9 For time point t, which is one of the two time points M within the time period t~t+Δt, the microlens L in the selected microlens group ij L ij+2 As shown. At this time, all pixels form a pixel group at time t, which, together with the microlens group selected at time t, constitutes a pixel group-microlens group structure at time t for integrated imaging display. Similarly, at time t+Δt / 2 within the time period t to t+Δt, all pixels form a pixel group at time t+Δt / 2, which, together with the microlens group selected at time t+Δt / 2 (including microlens L) ij+1 A pixel group-microlens group structure is constructed at time point t+Δt / 2 for integrated imaging display. This process is repeated. In this case, different pixel groups corresponding to different microlens groups are composed of the same pixels, but under the control of the control unit 30, at different time points in any time period, they correspond to the microlens groups selected at that time point. That is to say, using temporal characteristics as the selected orthogonal characteristics, M pixel groups are composed of the same pixels, but they have different temporal characteristics. This patent also considers them to be different pixel groups based on temporal characteristics. Obviously, the above-mentioned "time point" actually refers to a "time point" that includes a period of time. For example, the time point t+Δt / 2 within t~t+Δt can actually refer to a time period of Δt / 2 starting from t+Δt / 2.

[0076] The orthogonal characteristic can also be a color characteristic with M different wavelengths. In this case, sub-pixels can be used as the basic unit of display, and each pixel of the display device 20 is composed of sub-pixels that emit light of the M wavelengths. In this case, different microlens groups only allow light of the corresponding color to pass through. For example, each microlens is covered by its corresponding color filter. In this case, scenes of different colors will be displayed on different depth surfaces.

[0077] The orthogonal characteristic can also be a directional characteristic, where the light emitted from each pixel points to the corresponding microlens. In this case, the three-dimensional display module further includes a vector control device 70 composed of vector control units, such as... Figure 10 As shown. The vector control unit of the vector control device 70 corresponds one-to-one with each pixel or sub-pixel of the display device 20. Each vector control unit controls the propagation direction of the light emitted from the corresponding pixel or sub-pixel, guiding it to the projection of the corresponding microlens. Figure 10Taking M=2 as an example, pixels spaced M-1=1 pixels apart along the x-axis are grouped together, and microlenses spaced M-1=1 microlenses apart along the x-axis are grouped together. The microlenses in M=2 microlens groups have focal lengths f1 and f2 respectively. Specifically, the microlenses are…,…,L… i-1j L i-1j+2 、…,…、L ij L ij+2 、…,…、L i+1j L i+1j+2 ..., ... form a microlens group, with each microlens having a focal length of f1, called the f1 microlens group; microlenses ..., ..., L i-1j+1 L i-1j+3 、…,…、L ij+1 L ij+3 、…,…、L i+1j+1 L i+1j+3 A microlens group is formed by ..., ..., where each microlens has a focal length of f2, and is called the f2 microlens group. For clarity, only the three microlenses in the same row and some pixels are shown along the x-axis. The arrangement of other microlenses and pixels is easily understood by following the naming rules. In the subscripts of the names of each microlens and pixel, the first letter indicates the row number and the second letter indicates the column number. Pixel ..., ..., P i+3j P i+3j+2 P i+3j+4 P i+3j+6 P i+3j+8 P i+3j+10 ..., ..., P i+4j P i+4j+2 P i+4j+4 P i+4j+6 P i+4j+8 P i+4j+10 ..., ..., P i+5j P i+5j+2 P i+5j+4 P i+5j+6 P i+5j+8 P i+5j+10 ... are grouped together, corresponding to the f1 microlens group, and are called the f1 image group; pixels ..., ..., P i+3j+1 P i+3j+3 P i+3j+5 P i+3j+7 P i+3j+9 P i+3j+11 ..., ..., P i+4j+1 P i+4j+3 P i+4j+5 P i+4j+7 P i+4j+9 P i+4j+11 ..., ..., P i+5j+1 P i+5j+3 P i+5j+5 Pi+5j+7 P i+5j+9 P i+5j+11 ... are grouped together, corresponding to the f2 microlens group, and are called the f2 image group. The light emitted from each pixel is modulated by the corresponding vector control unit in the vector control device 70 and projected onto the corresponding microlens in the corresponding microlens group. More specifically, for example, P... i+4j P i+4j+2 P i+4j+4 P i+4j+6 P i+4j+8 P i+4j+10 Microlens L corresponding to the f1 image array ij Their emitted light is modulated by their respective corresponding vector control units, guiding the microlens L ij ;P i+4j+12 P i+4j+14 P i+4j+16 P i+4j+18 P i+4j+20 P i+4j+22 Microlens L corresponding to the f1 microlens group ij+2 Their emitted light is modulated by their respective corresponding vector control units, guiding the microlens L ij+2 ;P i+4j+5 P i+4j+7 P i+4j+9 P i+4j+11 P i+4j+13 P i+4j+15 Microlens L corresponding to the f2 microlens group ij+1 Their emitted light is modulated by their respective corresponding vector control units, guiding the microlens L ij+1 And so on. The adjacent microlenses L of the f1 microlens group... ij and L ij+2 The corresponding pixels are distributed in adjacent areas. Figure 10 Furthermore, if different pixel groups and microlens groups are configured with other distinct orthogonal characteristics—for example, pixel group f1 emits "·" light, and microlens group f1 only allows "·" light to pass through; pixel group f2 emits "-" light, and microlens group f2 only allows "-" light to pass through—this will help reduce crosstalk noise caused by non-corresponding microlenses passing through the projected light from each pixel. Of course, sub-pixels can also be used as the basic display unit, and the design can be similar. The vector control unit can be a micro / nano structure unit, such as a metasurface structure unit.

[0078] As described above, in each pixel group-microlens group structure, this patent requires a sufficiently high pixel viewpoint density in the y-direction to ensure that at least two beams of light, passing through each display point, are incident on the same pupil of the observer along this direction. However, the pixel viewpoint density in the x-direction can be lower than that in the y-direction. For example... Figure 2As shown, the integrated imaging display on two depth planes results from sacrificing the pixel viewpoint density in the x-direction. In fact, by introducing a one-way scatterer 50, when the effective light distribution area projected by each pixel onto the observer's surface via its corresponding microlens is larger in the x-direction than the observer's pupil diameter, the pixel viewpoint density corresponding to each microlens can be designed to be smaller in the x-direction than in the y-direction. For example, when the effective light distribution area corresponding to each pixel expands to the limit equal to the interpupillary distance in the x-direction, the pixel viewpoint spacing in the x-direction corresponding to each microlens in the same pixel group-microlens group structure can be as large as 1 / 2 of the interpupillary distance (if greater than 1 / 2, the light projected by one pixel may be seen by both pupils simultaneously, introducing significant crosstalk noise). Clearly, when using a conventional display device 20 with equal pixel spacing in the x and y directions, under the premise that the pixel viewpoint spacing in the x-direction corresponding to each microlens is not greater than 1 / 2 of the interpupillary distance, a larger M value can be selected, i.e., more orthogonal characteristic types, to generate greater depth-of-field extension based on more depth planes. For example, a combination of at least two or more of the aforementioned polarization state, temporal characteristics, directional characteristics, and color characteristics can provide a larger M value. Obviously, the y-axis pixel spacing p can also be selected. x Greater than the x-axis pixel spacing p y The display device 20. Alternatively, the sub-pixels can be arranged along the y-direction, with each sub-pixel serving as the basic display unit. Each microlens group and its corresponding sub-pixel group respectively construct a sub-pixel group-microlens group, and the display is implemented similarly to the above-described pixel group-microlens group display process. For example, a single pixel may contain three sub-pixels R, G, and B arranged along the y-direction, and p... x =p y The display screen serves as the display device 20, such as Figure 1 The sub-pixel display device 10 shown has an adjacent sub-pixel spacing along the y-direction of pixel p. x =p y One-third of the distance. At this point, the pixel spacing along the x-axis is three times the sub-pixel spacing along the y-axis. For high-quality color display, optimally, three times the sub-pixel viewpoint spacing along the y-axis should not exceed the observer's pupil diameter. Taking a y-axis sub-pixel viewpoint spacing of 1mm as an example, to ensure that at least three different color views can enter the same pupil of the observer with a pupil diameter of 3mm, then, when M=2 (for example, using polarized light as an orthogonal characteristic), the x-axis viewpoint spacing e corresponding to the same microlens... x =6mm. Therefore, Figure 1 As shown, with M=2 display depth planes, an eyebox of 60mm x-axis and 30mm y-axis requires a display resolution of 1 / 20th of the display device's resolution in the x-axis and 1 / 10th of the display device's resolution in the y-axis. In this case, each microlens corresponds to 10 pixel viewpoints along the x-axis and 30 sub-pixel viewpoints along the y-axis. Figure 3The pixel group-microlens group structure shown corresponds to 10×10 viewing areas. Considering the role of the one-way scatterer 50, a 30mm eyebox in the x-direction can be designed without scattering. Introducing the one-way scatterer 50 makes the x-direction size of the effective light distribution area corresponding to each pixel reach about 30mm, half the interpupillary distance. This ultimately allows for an eyebox with a 60mm x-direction and a 30mm y-direction. At this point, the x-direction display resolution is 1 / 10 of the display device resolution, and the y-direction display resolution is also 1 / 10 of the display device resolution, effectively improving the display resolution compared to traditional integrated imaging.

[0079] Clearly, the single pixel group-microlens group structure described in this patent can also be displayed independently (corresponding to only one pixel image plane), that is, when M is 1, the three-dimensional display module described in this patent can also be displayed. Especially based on p x ≠p y The display device 20 is used for display. By combining the one-way diffuser 50 and the sub-pixel viewpoint, it is possible to achieve a display where the effective size light distribution area of ​​the pixel in the x-direction is larger than the pupil diameter, and the effective size light distribution area of ​​the sub-pixel in the y-direction is smaller than the pupil diameter. For example, taking a display device 20 where each pixel contains three RGB sub-pixels arranged in the y-direction as an example, the sub-pixel spacing is 1 / 3 of the y-direction pixel spacing. A specific example design p... x =r1×p y You will get e x =r1×e y =3r1×(e y / 3). Where r1 is a positive integer. Further, let's set e more specifically. y Taking / 3=1mm and r1=7 as examples, the x-axis pixel viewpoint spacing (also the x-axis sub-pixel viewpoint spacing) is 21mm and the y-axis sub-pixel viewpoint spacing is 1mm. By extending the effective light distribution area corresponding to each sub-pixel along the x-axis using a one-way diffuser 50, a value within the range of 21mm to the interpupillary distance can be implemented for display.

[0080] The microlens also employs a micro / nano structure sensitive to orthogonal characteristics, exhibiting T′ focal lengths for each of the T′ orthogonal characteristics. For example, this micro / nano structure can be designed as a metasurface lens with T′ = two focal lengths for T′ = two linearly polarized lights (as T′ = two orthogonal characteristic lights) with mutually perpendicular polarization directions. In this case, in a pixel group-microlens group structure, all pixels in the pixel group, spaced T′-1 = 1 pixels apart along the x-direction, form pixel subgroups; these T′ = 2 pixel subgroups emit linearly polarized lights with mutually perpendicular polarization directions. Thus, these T′ = 2 pixel subgroups, through the microlens group, can perform the aforementioned integrated imaging display on two depth planes. Clearly, even a single pixel group-microlens group structure of this type can serve as a three-dimensional display module, realizing display on two depth planes. When the three-dimensional display module described in this patent contains M ≥ 2 such pixel group-microlens group structures, different pixel group-microlens group structures need to be designed to have different orthogonal characteristics in addition to the T′ type of orthogonal characteristics.

[0081] The microlens groups in the aforementioned microlens array 10 are designed to be arranged coplanarly. Their distances from the display device 20 can also be designed to be different, and the structures of each pixel group / microlens group are similarly implemented for display. In this case, the viewpoints corresponding to the pixels of each pixel group / microlens group can also be non-coplanar, and the pupil can receive at least two beams of light passing through any displayed object point, serving as the eyebox corresponding to that pupil. Furthermore, the display device 20 selected in this patent can be a flat screen or a curved screen.

[0082] Example 2

[0083] The three-dimensional display module described in this patent, compared to Embodiment 1, may further include a projection device 80, positioned in front of the microlens array 10 along the light transmission direction, such as... Figure 11 The lens shown is used to image the display device-microlens array structure. The projection device 80 can be a single lens, such as a Fresnel lens, or it can contain multiple optical elements, such as a combined lens. The projection device 80 can also be a lens-type device whose focal length changes sequentially under the control of the control unit 30, facilitating the use of electrically controlled liquid crystal lenses or combinations of multiple liquid crystal panels, where different combinations of liquid crystal panels correspond to different focal lengths. The projection device 80 can also be a lens-type device that has different focal lengths for incident light with different orthogonal characteristics, such as a micro / nano structure lens, which has different focal lengths for two types of linearly polarized light with mutually perpendicular polarization directions, such as a birefringent lens or a lens group composed of birefringent lenses, which has different focal lengths for two types of linearly polarized light with mutually perpendicular polarization directions, S-light and P-light. In this case, obviously, different microlens groups can also be set to have the same focal length, and the projection device 80 can be used to achieve the purpose of "projecting different pixel groups or sub-pixel groups to different depth surfaces," such as... Figure 12 Example. Specifically as Figure 12 In the example given, "·" and "-" represent two different orthogonal light states: linearly polarized S-beams and P-beams, respectively. The projection device 80 has focal lengths of f3 and f4 for these two different orthogonal light states, while each microlens has the same focal length f. Through the projection device 80, the "·" and "-" pixel groups are projected onto different "·" pixel image planes and "-" pixel image planes, respectively. Simultaneously, due to the different modulation capabilities of the projection device 80 for the "·" and "-" light, the viewpoint positions of the corresponding pixels for the "·" and "-" pixels also change and are no longer on the same plane. Clearly, under the condition that the orthogonality of the light emitted from each pixel remains unchanged after passing through the corresponding microlens, the "·" or "-" characteristics of each microlens can be removed, such as... Figure 13 As shown. Figure 13 In this configuration, the projection device 80 has focal lengths of f3 and f4 for the two different orthogonal light characteristics, respectively, while each microlens has the same focal length f. At this point, the microlenses in the microlens array 10 are no longer grouped; each microlens corresponds to pixels containing pixels with different orthogonal characteristics, based on the traditional integrated imaging principle. Specifically... Figure 13 microlens L ij For example, the corresponding pixel along the x-direction contains P i+4j+2 P i+4j+3 P i+4j+4 P i+4j+5 P i+4j+6 P i+4j+7 P i+4j+8 It occupies an area. Pixel P... i+4j+2 P i+4j+4 P i+4j+6 P i+4j+8 Emitting "·" light, pixel P i+4j+3 P i+4j+5 P i+4j+7 The emitted "-" light. Adjacent microlenses L ij+1 Its corresponding pixel along the x-direction contains P in the adjacent region. i+4j+9 P i+4j+10 P i+4j+11 P i+4j+12 P i+4j+13 P i+4j+14 P i+4j+15 It also emits "·" and "-" light respectively. Other microlenses and their corresponding pixels are set up similarly. Figure 13 Taking a microlens corresponding to 7 pixels as an example, it can also be set to other numbers of pixels. Figure 12 and Figure 13In the illustration, for clarity, the modulation effect of the projection device 80 on the incident light beam, particularly the change in the transmission path of the emitted light beam from the projection device 80, is not shown; this omission is readily understood by those skilled in the art. The three-dimensional display module described in this patent may further include a deflection device 90 placed along the light transmission path, such as... Figure 14 The illustrated automotive windshield deflects the light transmission path. The deflecting device 90 can also be a combination of multiple reflective surfaces. Furthermore, the functions of the deflecting device 90 and the projection device 80 can be combined into a single optical element, such as an automotive windshield with a curved reflector function, or implemented by a combined structure containing more than one optical element, such as a combination structure of transmissive and / or reflective freeform surfaces.

[0084] The three-dimensional display module described in this patent can also be used for a single eye of the observer. In this case, the eye box of the three-dimensional display module only needs to cover the corresponding pupil, and each eye of the observer can correspond to one of the three-dimensional display modules to achieve binocular display.

[0085] The above are merely preferred embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept also fall within the protection scope of the present invention. For example, various possible and mutually identifiable optical characteristics can be selected as the orthogonal characteristics of this patent. All devices capable of quantitatively expanding the divergence angle along a one-dimensional direction can be used as unidirectional scatterers. Accordingly, all related embodiments fall within the protection scope of the present invention.

Claims

1. A three-dimensional display module based on a multi-focal-length microlens array, characterized in that, include: Microlens array (10), which is composed of a two-dimensional arrangement of microlenses, wherein along one dimension x Direction, Interval M The microlenses, each consisting of one microlens, are grouped together. M Each microlens group is endowed with different orthogonal properties. Each microlens group only allows light with corresponding orthogonal properties to be modulated and emitted, and microlenses belonging to different groups have different focal lengths. M ≥2; The display device (20) includes multiple pixels or multiple sub-pixels and is placed corresponding to the microlens array (10) to form a display device-microlens array structure; In the display device-microlens array structure, each microlens of any microlens group corresponds to a pixel or sub-pixel on the display device (20), forming a corresponding pixel group or sub-pixel group of the microlens group. The emitted light characteristics of each pixel group or sub-pixel group are set to be consistent with the orthogonal characteristics of the corresponding microlens group, and the corresponding pixels or sub-pixels of adjacent microlenses in the same group belong to different regions. Control unit (30), which is connected to display device (20) and can control the light information loaded on each pixel or sub-pixel, which is the projection light information of the scene to be displayed along the line connecting the pixel or sub-pixel and the corresponding microlens; In this configuration, each pixel or sub-pixel projects a light beam onto the observation surface of the eyebox via a corresponding microlens. Furthermore, along at least one direction, the pixel-to-viewpoint spacing or sub-pixel-to-viewpoint spacing corresponding to each microlens is smaller than the observer's pupil diameter. This ensures that, for any object to be displayed, the pupil within the eyebox can receive at least two light beams passing through that object. Wherein, along at least one direction, the pixel viewpoint spacing or sub-pixel viewpoint spacing corresponding to the microlens refers to the distance between the projection points of adjacent pixels or adjacent sub-pixels corresponding to the same microlens along that direction, when the light beams projected by the microlens are placed on the observation surface of the eyebox.

2. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1, characterized in that, The three-dimensional display module also includes a pupil tracking unit (40) connected to the control unit (30). The pupil tracking unit (40) is used to track and locate the position of the observer's pupil in real time, and determine the corresponding pixel or sub-pixel of each microlens according to the position of the observer's pupil, so as to ensure that the eye box tracks and covers the observer's pupil.

3. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1, characterized in that, The three-dimensional display module also includes a one-way scatterer (50), which is attached to the microlens array (10) and positioned along... x Directional scattering of incident light; The one-way scatterer (50) is configured such that: a light beam from any corresponding pixel or sub-pixel, after being scattered by the one-way scatterer (50), has an effective light distribution area on the observation surface where the eyebox is located, with a light intensity greater than 10% of its extreme intensity. x The directional dimension is smaller than the interpupillary distance of the observer.

4. The three-dimensional display module based on a multi-focal-length microlens array according to claim 3, characterized in that, The three-dimensional display module also includes a pupil tracking unit (40) connected to the control unit (30). The pupil tracking unit (40) is used to track and locate the position of the observer's pupil in real time. For each pixel or sub-pixel that intersects with the observer's pupil in the effective light distribution area, the control unit (30) can control the loading information as: the projection light information of the scene to be displayed along the direction of the connection between the observer's pupil and the microlens corresponding to the pixel or sub-pixel.

5. The three-dimensional display module based on a multi-focal-length microlens array according to claim 3, characterized in that... The three-dimensional display module also includes a pupil tracking unit (40) connected to the control unit (30). The pupil tracking unit (40) is used to track and locate the position of the observer's pupil in real time and determine the corresponding pixel of each microlens according to the position of the observer's pupil, so as to ensure that the eye box tracks and covers the observer's pupil.

6. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, Each microlens is fitted with an aperture that is the same number as the number of sub-pixel types, and these multiple apertures allow the color light projected by different types of sub-pixels to pass through.

7. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, The orthogonality property is M A series of mutually orthogonal polarization states; The M Each microlens group corresponds to M A group of pixels, for along x Pixels spaced one pixel apart in each direction are grouped together. M The emitted light from each pixel group is as follows: M Light in three mutually orthogonal polarized states, among which M =2.

8. The three-dimensional display module based on a multi-focal-length microlens array according to claim 7, characterized in that, The orthogonal characteristics of each pixel or sub-pixel and each microlens are achieved through their respective attached polarizers.

9. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, It also includes a timing control device (60) connected to the control unit (30), the orthogonality being... M The timing characteristics are activated at each time point, and the timing control device (60) can control the timing characteristics at each time period. M At each time point, timing gating M The aperture of each microlens group Among them, the M Each microlens group corresponds to M Each pixel group or sub-pixel group contains the same pixels or sub-pixels, but is activated at different time points in each time period under the control of the control unit (30), so as to correspond to the aforementioned pixels or sub-pixels at different time points. M A group of microlenses.

10. The three-dimensional display module based on a multi-focal-length microlens array according to claim 9, characterized in that, The orthogonal characteristics of each microlens are controlled by the control unit (30) and the timing control device (60) to controllably select the light transmission aperture of each microlens.

11. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, The orthogonal characteristic is a directional characteristic, where the light emitted from each pixel or sub-pixel points to the corresponding microlens.

12. The three-dimensional display module based on a multi-focal-length microlens array according to claim 11, characterized in that, The three-dimensional display module also includes a vector control device (70) composed of a vector control unit. The vector control unit corresponds one-to-one with each pixel or sub-pixel of the display device (20) and is used to control the projection direction of the light emitted from the corresponding pixel or sub-pixel.

13. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, The orthogonality property is M Color characteristics of different wavelengths; The M Each microlens group corresponds to M A group of sub-pixels, formed by along x The sub-pixels with a directional spacing of (M-1) sub-pixels each form the structure. M Each sub-pixel group emits separately M Light of different wavelengths and colors.

14. The three-dimensional display module based on a multi-focal-length microlens array according to claim 13, characterized in that, The orthogonal characteristics of each sub-pixel and each microlens are achieved through their respective attached color filters.

15. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, The orthogonal characteristic is a combination of at least two of the following: polarization state, timing characteristic, pointing characteristic, and color characteristic.

16. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, The microlens is a micro / nano structure with lens function.

17. The three-dimensional display module based on a multi-focal-length microlens array according to claim 16, characterized in that, The microlens along x The direction and its vertical spacing are different.

18. The three-dimensional display module based on a multi-focal-length microlens array according to claim 16, characterized in that, This microlens exhibits polarization state sensitivity. T′ The polarization states are respectively manifested as T′ Focal length, among which T′ ≧1, Among them, the pixel group corresponding to the same microlens group is divided into T′ pixel subgroups, and each of the T′ pixel subgroups emits light in T′ polarized states.

19. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, It also includes a projection device (80), which is positioned in front of the microlens array (10) along the light transmission direction to image the display device-microlens array structure. The projection device (80) is a single optical element or a combination of multiple optical elements.

20. The three-dimensional display module based on a multi-focal-length microlens array according to claim 1 or 3, characterized in that, It also includes a deflection device (90) placed in the light transmission path to guide the transmission direction of the incident light. The deflection device (90) is a single optical element or a combination of multiple optical elements.

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