Diffusion plate and display device

Abstract

The application provides a diffusion plate and a display device. The diffusion plate comprises: a diffusion plate body; and an array of microstructure units, comprising a plurality of microstructure units arranged on one side of the diffusion plate body, wherein the plurality of microstructure units are formed in an array form, and the column width of each column is a random value. The diffusion plate provided by the application can inhibit speckle of an image and achieve a uniform rectangular diffusion effect.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to a diffuser plate and a display device. Background Technology

[0002] A diffuser is a widely used optical component, finding significant applications in products such as head-up displays (HUDs), lidar, and projection systems. A diffuser modulates incident light, creating a uniform light field at the desired field of view. As applications such as HUDs evolve towards higher content, larger screen sizes, higher resolution, longer viewing distances, higher brightness, and smaller dimensions, higher demands are placed on diffusers. In these applications, image generation units (PGUs) based on laser light sources and microelectromechanical systems (MEMS) scanning micromirrors can replace traditional digital light processing-image generation units (DLP-PGUs), offering advantages such as higher imaging resolution, smaller size, and lower power consumption.

[0003] However, diffuser plates still have many limitations in current practical applications. For example, due to the long coherence length of the laser source, strong coherence effects occur when incident on the diffuser plate, ultimately forming speckle on the image and affecting image quality. Furthermore, methods to eliminate speckle by changing the arrangement of microlenses result in an elliptical diffusion range, failing to achieve a satisfactory rectangular diffusion effect. Methods to eliminate speckle by adding height to the microlens surface can lead to excessive height differences between the center of the surface, affecting the surface appearance of the diffuser plate. Summary of the Invention

[0004] An embodiment of this application provides a diffusion plate, which includes: a diffusion plate body; and a microstructure unit array, including a plurality of microstructure units disposed on one side of the diffusion plate body, wherein the plurality of microstructure units are formed in an array form, and the column width of each column is a random value.

[0005] In one implementation, the minimum column width is greater than or equal to 0.6 times the maximum column width.

[0006] In one embodiment, the column width is between 15 μm and 100 μm.

[0007] In one implementation, the row height of each row in the microstructure unit array is a random value.

[0008] In one implementation, the minimum row height is greater than or equal to 0.6 times the maximum row height.

[0009] In one embodiment, the row height is between 15 μm and 100 μm.

[0010] In one embodiment, the projection of the row boundaries in the microstructure unit array onto the diffuser plate body is a straight line, and the projection of the column boundaries in the microstructure unit onto the diffuser plate body is a straight line.

[0011] In one embodiment, the rows are perpendicular to the columns, and adjacent rows are aligned and adjacent columns are aligned.

[0012] In one embodiment, the height difference between the vertices of the plurality of microstructure units is less than or equal to 1.5 μm in a direction perpendicular to the diffuser plate body.

[0013] In one embodiment, the product of the square of the column width of the microstructure unit and the curvature of the microstructure unit at its vertices along the direction of the column width is a first constant value.

[0014] In one embodiment, the product of the square of the row height of the microstructure unit and the curvature of the microstructure unit at its vertices along the direction of the row height is a second constant value.

[0015] Secondly, embodiments of this application provide a display device, which includes a diffuser plate as described in any of the above embodiments; and a light source disposed on one side of the diffuser plate for emitting a light beam to be diffused toward the diffuser plate.

[0016] In one embodiment, the light source includes a laser light source.

[0017] The diffusion plate provided according to this application may have at least one of the following advantages:

[0018] 1) The diffuser plate provided in this application can eliminate the periodicity of the surface arrangement of microstructure units, thereby suppressing speckle in the image.

[0019] 2) The diffusion plate provided in this application achieves a better rectangular diffusion effect by aligning the row and column boundaries of the microstructure unit array.

[0020] 3) The diffusion plate provided in this application can reduce the height difference between the surfaces of microstructure units and improve the uniformity of diffusion by adjusting the row height and column width in the microstructure unit array and adjusting the surface curvature of the microstructure units. Attached Figure Description

[0021] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. In the drawings:

[0022] Figure 1 It is a surface diagram of a microstructure unit array based on existing technology when the boundaries are not adjusted;

[0023] Figure 2 It is based on Figure 1 Optical diffraction pattern of the microstructure unit array in the image;

[0024] Figure 3 This is a schematic diagram of a diffusion plate according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram showing the row height and column width of the microstructure unit array according to an embodiment of this application, with initial values;

[0026] Figure 5 This is a schematic diagram showing that the row height and column width of the microstructure unit array according to an embodiment of this application are set to random values;

[0027] Figure 6 This is a schematic diagram of the surface distribution of microstructure units with unadjusted curvature in a microstructure unit array according to an embodiment of this application;

[0028] Figure 7 It is based on Figure 6 The projection profile of the microstructure unit in the diffuser plate on a cross section perpendicular to the diffuser plate body;

[0029] Figure 8 It is based on Figure 6 Diffraction effect diagram of the microstructure unit in the image;

[0030] Figure 9 This is a schematic diagram of the surface distribution of microstructure units with curvature adjustment in a microstructure unit array according to an embodiment of this application;

[0031] Figure 10 It is based on Figure 9 The projection profile of the microstructure unit in the diffuser plate on a cross section perpendicular to the diffuser plate body;

[0032] Figure 11 It is based on Figure 9 Diffraction patterns of the microstructure units in the image; and

[0033] Figure 12 This is a schematic block diagram of a display device according to an embodiment of this application. Detailed Implementation

[0034] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features, especially not any order of precedence. Therefore, without departing from the teachings of this application, the first side of the diffuser plate body discussed in this application may also be referred to as the second side of the diffuser plate body, and vice versa.

[0036] In the accompanying drawings, the thickness, dimensions, and shapes of the components have been slightly adjusted for ease of illustration. The drawings are for illustrative purposes only and are not drawn to scale. For example, the width of the microstructural units depicted in the drawings in this application is not proportional to actual production. Terms such as “approximately,” “about,” and similar expressions used herein are used as terms of approximation, not as terms of degree, and are intended to illustrate inherent deviations in measured or calculated values ​​that will be recognized by those skilled in the art.

[0037] It should also be understood that expressions such as "comprising," "including," "having," "containing," and / or "comprising" are open-ended rather than closed-ended expressions in this specification, indicating the presence of the stated features, elements, and / or components, but not excluding the presence of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not just individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to examples or illustrations.

[0038] Unless otherwise specified, all terms used herein (including engineering and technical terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that, unless expressly stated herein, terms defined in common dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or overly formalized meaning.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] The features, principles and other aspects of this application are described in detail below.

[0041] Figure 1This is a surface view of a prior art microstructure unit array 110. The prior art microstructure unit array 110 is composed of an array of multiple microstructure units 111. In each row of the prior art microstructure unit array 110, the multiple microstructure units 111 have the same width in the direction perpendicular to the row. In each column of the prior art microstructure unit array 110, the multiple microstructure units 111 have the same width in the direction perpendicular to the column. The rows and columns in this microstructure unit array 110 can be perpendicular to each other. Obviously, before adjustment, the multiple microstructure units 111 in the prior art microstructure unit array 110 have the same shape and size. Its optical diffraction pattern is as follows: Figure 2 As shown, it can be seen that the diffraction image of the microstructure unit array 110 according to the prior art has obvious speckle phenomenon, and there is obvious display difference between bright and dark areas on the diffraction image.

[0042] Through the Figure 1 By altering the curvature and surface height of the existing microstructure unit array 111, the formation of diffraction speckle can be suppressed. However, due to the presence of the diffuser plate body 10 ( Figure 3 All the microstructure units 111 on the array have the same bottom surface size, resulting in a periodic bottom surface pattern in the prior art microstructure unit array 110. This periodic structure will interfere under single-wavelength laser diffraction conditions, producing interference fringes. For example... Figure 2 As shown, the uniformly and closely arranged microstructure units 111 will produce obvious interference fringes under diffraction conditions.

[0043] Figure 3 This is a schematic structural diagram of the diffuser plate 100 according to an embodiment of this application. Figure 3 As shown, the diffuser plate 100 may include a microstructure unit array 120. Figure 3 The portion within the dashed box and the diffuser plate body 10, wherein the microstructure unit array 120 includes a plurality of microstructure units 121. The diffuser plate body 10 in the diffuser plate 100 has opposing first and second sides, specifically, Figure 3 The lower side shown can be the first side, and the upper side can be the second side. Multiple microstructure units 121 are arranged in an array on the second side of the diffuser plate body 10.

[0044] The implementation of this application disrupts the boundary by adding a random quantity. Figure 2 The periodicity of the bottom surface shape of the microstructure unit 111 shown suppresses the interference effect. Figure 4 This is a schematic diagram showing the row height and column width of the microstructure unit array according to an embodiment of this application when they are at their initial values. The microstructure unit array of this application can be obtained by changing these initial values. Figure 4As shown, for the microstructure unit array 110 without boundary adjustments, the bottom surface 11 of the microstructure unit 111 is rectangular, and the column boundaries 12 in the microstructure unit array 110 are uniformly arranged. In an exemplary embodiment, the row boundaries 14 in the microstructure unit array 110 are uniformly distributed. Exemplarily, both the column boundaries 12 and the row boundaries 14 in the microstructure unit array 110 are uniformly distributed, and the spacing between the column boundaries 12 and the spacing between the row boundaries 14 can be the same.

[0045] refer to Figure 5 The illustration shows a microstructure unit array according to an embodiment of this application. In this embodiment, the microstructure unit array 120 has edges... Figure 5 Multiple vertically arranged microstructural units 121 are used to form columns, along... Figure 5 Multiple microstructural units 121 arranged horizontally are used to form rows. The area enclosed by a pair of adjacent row boundaries 15 and a pair of adjacent column boundaries 13 is used to define a microstructural unit 121. Two adjacent microstructural units 121 are fitted together, that is, two adjacent columns are tightly fitted together, and exemplarily, two adjacent rows are fitted together. In fact, the usage posture of the diffusion plate provided in this application is not limited to this. Figure 5 The posture shown indicates that rows in this article can actually be columns, and columns can also be rows.

[0046] The row height and column width of the microstructure unit array 120 in this embodiment are set to random values. Exemplarily, for... Figure 4 The microstructure unit array 110 shown has all column boundaries 12 with a certain amount of variation. The sum of the variations of the two column boundaries 13 of a column can be within 25% of the column width. For example, the variation of one column boundary of a column can be within 20% of the column width, and the variation of the other column boundary can be within 5% of the column width. For example, the variation of one column boundary of a column can be 25% of the column width, while the other column boundary can remain unchanged. For example, the variation of both column boundaries of a column can be within 12.5% ​​of the column width. The variation of row height is set similarly to that of column width.

[0047] The adjusted microstructure unit array 120 provided in this embodiment satisfies: 0.75L y0 ≤L≤1.25L y0 , where L y To adjust the column width of the microstructure unit array 120, L y0The column width of the microstructure unit array 110 before boundary adjustments is defined. The adjusted column boundaries 13 are randomly generated within the aforementioned range of variation, based on the original column boundary 12. The distance between two adjacent column boundaries 13 is the adjusted column width. In some embodiments, the average value of the adjusted column width of the microstructure unit array 120 is essentially the same as the initial column width of the microstructure unit 111 before adjustment. For example, the multiple variations generated along the column arrangement direction are aperiodic values; for example, the multiple variations corresponding to the row height are also aperiodic values.

[0048] Similarly, the row boundaries 14 in the original microstructure unit array 110 are transformed into row boundaries 15. The distance between two adjacent row boundaries 15 is the row height after adjustment. The transformed row height satisfies 0.75L. x0 ≤L x ≤1.25L x0 , where L x For the adjusted row height of the microstructure unit array 120, L x0 The row height of the microstructure unit array 110 when the boundaries are not adjusted.

[0049] For example, Figure 4 The initial value can be 50 μm. The adjusted column width and row height of the microstructure unit array 120 are between 37.5 μm and 62.5 μm, respectively. Of course, since the row height and column width are random, boundary values ​​may not be included. Furthermore, the minimum row height of the microstructure unit array 120 is greater than or equal to 0.6 times the maximum row height.

[0050] Specifically, the row height of the unadjusted microstructure unit array 110 can be in the range of 20μm to 80μm, and the row height of each row of the adjusted microstructure unit array 120 can be between 15μm and 100μm. For example, if the row height of each row of the unadjusted microstructure unit array 110 is a fixed value, such as 80μm, then the row height of each row of the adjusted microstructure unit array 120 can be, for example, between 60μm and 100μm. For example, the row height of multiple rows in the adjusted microstructure unit array 120 can be, for example, between 45μm and 75μm, or for example, between 15μm and 25μm. The row heights of multiple rows can be the same or different, but at least two row heights must be different. The column width of each column of the adjusted microstructure unit array 120 can also be between 15μm and 100μm, and the row heights between columns can be the same or different, but at least two column widths must be different. The row height and column width can be the same or different. By limiting the range of row height, excessive differences in local diffusion performance can be avoided, as well as excessive height differences between adjusted microstructural units.

[0051] In this embodiment, columns are bonded together, and rows are also bonded together. Specifically, any two adjacent microstructure units are bonded together in the row extension direction, and any two adjacent microstructure units are bonded together in the column extension direction. There are no gaps between the bonded microstructure units, resulting in better diffusion and fewer dark areas in the diffuser plate.

[0052] The diffuser provided in this application has adjusted column boundaries and adjusted row boundaries. The shape of the microstructure unit is restricted within two adjacent column boundaries and two adjacent row boundaries, thus disrupting the periodicity of the bottom surface profile of the microstructure unit. The array of microstructure units arranged in this way can suppress speckle and interference fringes when used for diffused light.

[0053] Figure 6 This is a schematic diagram of the surface distribution of microstructure units in the adjusted microstructure unit array. Figure 7 An illustrative diagram shows the surface height distribution of a row of microstructural units 121 with adjusted boundaries. Exemplarily, all microstructural units 121 have similar curvature, but significant height differences between their surfaces. Microstructural units 121 of different sizes exhibit slightly different light diffusion effects.

[0054] refer to Figure 8 The diffusion effect of the diffuser plate was improved, and the number and area of ​​dark areas decreased. However, its diffraction pattern still showed inhomogeneity, which affected the diffusion effect.

[0055] In an exemplary embodiment, the curvature of the microstructure unit 121 after boundary adjustment can be further adjusted, and the surface formula of the microstructure unit 131 after curvature adjustment is:

[0056]

[0057] in, Figure 6 In the diagram, the X and Y directions represent the row height and column width, respectively. x and y are the coordinates of a point on the surface in these two directions. C x and C y Let k be the curvature of the microstructure unit 131 after curvature adjustment in the X and Y directions. x and k y These are the conic coefficients in the X and Y directions, respectively. The parameters in this surface shape formula are obtained by adjusting the curvature of each microstructural unit 111 according to the row height and column width, i.e. Among them, C x0 C y0The curvature of microstructure unit 111 is the one whose boundary and curvature have not been adjusted. When adjusting the boundary of microstructure unit 111, its curvature may not be adjusted. Then, the curvature of microstructure unit 121 after boundary adjustment is adjusted to form microstructure unit 131.

[0058] It can be understood that, after adjusting the aforementioned equations for parameter adjustment, we can obtain the following: the product of the square of the column width of microstructure unit 131 and the curvature of the microstructure unit at its vertex along the column width direction is the first constant value k2. Similarly, the product of the square of the row height of microstructure unit 131 and the curvature of the microstructure unit at its vertex along the row height direction is the second constant value k1. The first constant value k2 and the second constant value k1 can be the same or different.

[0059] The first fixed value k2 and the second fixed value k1 are obtained based on the initial values ​​during design and may differ in different embodiments. For a microstructure unit array, the first fixed value k2 corresponding to each microstructure unit can be the same. The second fixed value k1 is similar.

[0060] Multiple curvature-adjusted microstructural units 131 form a microstructural unit array 130. The surface shape of the curvature-adjusted microstructural unit array 130 is as follows: Figure 9 As shown. Furthermore, Figure 10 An exemplary projection of a row of curvature-adjusted microstructural units 131 is shown. The maximum height difference between the surfaces of the curvature-adjusted microstructural units 131 is significantly reduced compared to the maximum height difference between the surfaces of the microstructural units 121 before curvature adjustment. Specifically, the multiple curvature-adjusted microstructural units 131 in... Figure 10 The height difference between the maximum points on the vertical axis in the projection diagram shown is less than 1.5 μm. For example, random height values ​​can be further added to the multiple microstructural units 131 after curvature adjustment, but the maximum height difference between the multiple microstructural units 131 must be less than 1.5 μm.

[0061] The diffraction effect of the diffuser plate provided in this embodiment is as follows: Figure 11 As shown, the interference fringes are further suppressed, the diffraction pattern is more uniform, and the diffusion effect is good.

[0062] The row height refers to its dimension in the direction perpendicular to the row extension direction, and the column width refers to the dimension of the column in the direction perpendicular to the column extension direction. Another aspect of this application provides a display device 200. This display device may include a diffuser plate 100 and a light source 210. The diffuser plate 100 may be any of the diffuser plates described in the above embodiments, for example… Figure 3 The diffuser plate 100 shown.

[0063] Figure 12 This is a schematic block diagram of a display device according to an embodiment of this application.

[0064] The light source 210 emits image light carrying light source information to the diffuser plate 100. After receiving the image light, the diffuser plate 100 modulates it and projects a uniform light field. The diffuser plate 100 may include a diffuser plate body 10 and a microstructure unit array 130. The image light emitted by the light source 210 enters the diffuser plate body 10 from the microstructure unit array 130 and is then projected out from the diffuser plate body 10.

[0065] The diffuser plate body 10 has opposing first and second sides, specifically, Figure 12 The left side of the diffuser plate 100 shown can be the second side, and the right side can be the first side. Multiple microstructure units 131 are arrayed on the second side of the diffuser plate body 10. Further, the image light emitted by the light source 210 enters from the second side of the microstructure unit array 130, is modulated within the microstructure unit array 130, and then enters the diffuser plate body 10 before being projected out from the first side of the diffuser plate body 10.

[0066] According to one example, the light source 210 in the display device 200 of this application may include a laser light source, or other light sources such as LED light sources. The laser light source emits image light carrying information to the diffuser plate 100, which receives the image light, modulates it, and projects a uniform light field. The display device provided by this application can suppress speckle in the image and form a uniformly diffused rectangular diffraction image.

[0067] Since the content and structure described above regarding the diffuser plate 100 are applicable in whole or in part to the display device described herein, related or similar content will not be repeated.

[0068] The above description is merely an illustration of the embodiments of this application and the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the technical concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A diffuser plate, characterized in that, include: Diffuser plate body; as well as The microstructure unit array includes multiple microstructure units disposed on one side of the diffuser plate body, wherein the multiple microstructure units are formed in an array, and the column width of each column is a random value. In the microstructure unit array, the rows and columns are perpendicular, and adjacent rows are fitted together, and adjacent columns are fitted together; The projection of the row boundary in the microstructure unit array onto the diffuser plate body is a straight line, and the projection of the column boundary in the microstructure unit onto the diffuser plate body is a straight line. The product of the square of the column width of the microstructure unit and the curvature of the microstructure unit at its vertices along the column width direction is a first fixed value; or the product of the square of the row height of the microstructure unit and the curvature of the microstructure unit at its vertices along the row height direction is a second fixed value.

2. The diffuser plate according to claim 1, characterized in that, The minimum column width is greater than or equal to 0.6 times the maximum column width.

3. The diffuser plate according to claim 2, characterized in that, The column width is between 15μm and 100μm.

4. The diffuser plate according to any one of claims 1 to 3, characterized in that, The row height of each row in the microstructure unit array is a random value.

5. The diffuser plate according to claim 4, characterized in that, The minimum value of the row height is greater than or equal to 0.6 times the maximum value of the row height.

6. The diffuser plate according to claim 5, characterized in that, The row height is between 15 μm and 100 μm.

7. The diffuser plate according to claim 1, characterized in that, In a direction perpendicular to the diffuser plate body, the height difference between the vertices of the plurality of microstructure units is less than or equal to 1.5 μm.

8. A display device, characterized in that, include: The diffuser plate as described in any one of claims 1 to 7; as well as A light source is disposed on one side of the diffuser plate and is used to emit a light beam to be diffused onto the diffuser plate.

9. The display device according to claim 8, characterized in that, The light source includes a laser light source.

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