Diffuser 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, wherein the column width of each column is a random value, and wherein, in a plane parallel to the diffusion plate body, the microstructure units comprise a long axis and a short axis perpendicular to each other, and the angle between the long axis and the 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 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 that eliminate speckle by randomly arranging microlenses result in an elliptical diffusion range, failing to achieve a satisfactory rectangular diffusion effect. Methods that eliminate speckle by adding random heights to the microlens surfaces lead to excessive height differences between the center points of the surfaces, 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, wherein the column width of each column is a random value; and wherein, in a plane parallel to the diffusion plate body, the microstructure unit includes a major axis and a minor axis that are perpendicular to each other, and the angle between the major axis and the column is a random value.

[0005] In one embodiment, the row height of the microstructure unit is greater than or equal to the column width, and the angle between the major axis and the column is less than or equal to 45°.

[0006] In one embodiment, the column width of the microstructure unit is greater than the row height, and the angle between the major axis and the column is between 45° and 90°.

[0007] In one implementation, the minimum column width is greater than or equal to 0.6 times the maximum column width.

[0008] In one embodiment, the column width is between 15 μm and 100 μm.

[0009] In one implementation, the row height of each row in the microstructure unit array is a random value.

[0010] In one implementation, the minimum row height is greater than or equal to 0.6 times the maximum row height.

[0011] In one embodiment, the row height is between 15 μm and 100 μm.

[0012] 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.

[0013] In one embodiment, the rows are perpendicular to the columns, and adjacent rows are aligned and adjacent columns are aligned.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] In one embodiment, the light source includes a laser light source.

[0019] The diffusion plate provided according to this application may have at least one of the following advantages:

[0020] 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.

[0021] 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.

[0022] 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

[0023] 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:

[0024] Figure 1 It is a surface diagram of a microstructure unit array based on existing technology when the boundaries are not adjusted;

[0025] Figure 2 It is based on Figure 1 Optical diffraction pattern of the microstructure unit array in the image;

[0026] Figure 3 This is a schematic diagram of a diffusion plate according to an embodiment of this application;

[0027] 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;

[0028] 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;

[0029] Figure 6 This is a schematic diagram of the surface distribution of microstructure units with unadjusted curvature in the microstructure unit array according to this application;

[0030] 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;

[0031] Figure 8 It is based on Figure 6 Diffraction effect diagram of the microstructure unit in the image;

[0032] Figure 9 This is a schematic diagram of the surface distribution of microstructure units in a microstructure unit array after random rotation by a certain angle according to the embodiments of this application;

[0033] Figure 10 This is a schematic diagram of the surface distribution of microstructure units in a microstructure unit array after curvature and angle adjustment according to an embodiment of this application;

[0034] Figure 11 It is based on Figure 10 The projection profile of the microstructure unit in the diffuser plate on a cross section perpendicular to the diffuser plate body;

[0035] Figure 12 It is based on Figure 10 Diffraction patterns of the microstructure units in the image; and

[0036] Figure 13 This is a schematic block diagram of a display device according to an embodiment of this application. Detailed Implementation

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The features, principles and other aspects of this application are described in detail below.

[0044] Figure 1 This is a schematic diagram of the surface distribution 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 the prior art microstructure unit array 110 are perpendicular to each other. Obviously, without adjustment, the shape and size of the multiple microstructure units 111 in the prior art microstructure unit array 110 can be identical. 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.

[0045] Through the Figure 1 Adding random amounts to the curvature and surface height of the existing microstructure unit array 111 can suppress the formation of diffraction speckles. However, since all the microstructure units 111 on the diffuser plate body (not shown) have the same bottom surface size, the bottom surface of the existing microstructure unit array 110 has periodicity. Periodic structures 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.

[0046] Figure 3 This is a schematic diagram of a diffusion 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 3The portion within the dashed box and the diffuser plate body 140, wherein the microstructure unit array 120 is composed of multiple microstructure units 121. The diffuser plate body 140 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 140.

[0047] The embodiments of this application suppress interference effects by adding random quantities to the boundaries to disrupt the periodicity of the bottom surface shape of the prior art microstructure unit 111. 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. For example... Figure 4 As shown, for the microstructure unit array 110 without boundary adjustments, the bottom surface shape 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.

[0048] In this embodiment of the application, the microstructure unit array 120 along Figure 4 Multiple vertically arranged microstructural units 121 are used to form columns, along... Figure 4 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 4 The posture shown indicates that rows in this article can actually be columns, and columns can also be rows.

[0049] Figure 5 This is a schematic diagram showing that the row height and column width of a microstructured unit array according to an embodiment of this application are set to random values. For example, a certain amount of variation is set for all column boundaries 12 of a prior art microstructured unit array 110, and 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 is within 20% of the column width, and the variation of the other column boundary is within 5% of the column width. For example, the variation of one column boundary of a column is 25% of the column width, and the other column boundary may not be adjusted. 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.

[0050] The adjusted microstructure unit array 120 provided in this embodiment satisfies: 0.75L y0 ≤Ly≤1.25L y0 Where Ly is the adjusted column width of the microstructure unit array 120, L y0 The column width of the microstructure unit array 110 before boundary adjustment is performed. The adjusted column boundary 13 is then randomly generated within the aforementioned range of variation, based on the column boundary 12 before adjustment. Specifically, 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.

[0051] Similarly, the row boundary 14 in the microstructure unit array 110 before adjustment is transformed into row boundary 15, and the transformed row height satisfies 0.75L. x0 ≤Lx≤1.25L x0 Where Lx is 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.

[0052] Specifically, the row height of each row in the adjusted microstructure unit array 120 can be between 15 μm and 100 μm. Multiple rows can have the same or different row heights, but at least two row heights must be different. Similarly, the column width of each column in the adjusted microstructure unit array 120 can also be between 15 μm and 100 μm. 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.

[0053] 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.

[0054] 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.

[0055] Figure 6 This is a schematic diagram of the surface distribution of microstructure units in the microstructure unit array after column width and row height adjustments. Figure 7An illustrative diagram illustrates the surface height distribution of a row of microstructural units 121 after boundary adjustment. Exemplarily, all the boundary-adjusted microstructural units 121 have similar curvature, but the height differences between their surfaces are significant. The light diffusion effect varies slightly among microstructural units 121 of different sizes after boundary adjustment. (Reference) 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.

[0056] In an exemplary embodiment, the curvature of the microstructure unit 121 after boundary adjustment can be further adjusted.

[0057] The formula for the surface type of microstructure unit 131 after curvature adjustment is:

[0058]

[0059] Where X and Y are the row height and column width directions of the microstructure unit array 110, and x and y are the coordinates of a point on the surface along the corresponding axis. x and C y Let be the curvature of the microstructure unit 131 after curvature adjustment in the X and Y directions, and kx and ky be the conic coefficients in the X and Y directions, respectively. The parameters in this surface formula are obtained by adjusting the curvature of each microstructure unit 111 according to the row height and column width, i.e. C x0 C y0 The curvature of the microstructure unit 111 is given by which neither the boundary nor the curvature has been adjusted. The surface of the microstructure unit after curvature adjustment may have a major axis and a minor axis that are perpendicular to each other in the plane perpendicular to the surface axis.

[0060] For example, the curvature-adjusted microstructure units can be rotated to disrupt the periodicity of the microstructure unit array 120, further suppressing speckle and interference fringes. Specifically, the microstructure unit 121 rotates around a point P perpendicular to its own bottom surface and passing through the center of its own bottom surface. Figure 9 The microstructure unit 121 rotates around its surface axis, with each microstructure unit 121 rotating randomly around its surface axis, specifically between -45° and 45°. An angle of clockwise rotation is recorded as a positive value, and an angle of counterclockwise rotation is recorded as a negative value. The resulting microstructure unit array 130 has the following surface distribution: Figure 9 As shown.

[0061] like Figure 9As shown, in a plane parallel to the diffuser plate body 140, the microstructure unit 131 includes a major axis and a minor axis that are perpendicular to each other. The angle between the major axis and the column in the microstructure unit array 130 can be a random value. For example, when the row height of the microstructure unit array 130 is greater than the column width, the angle between the major axis and the column in the microstructure unit array 130 is less than or equal to 45°. When the column width of the microstructure unit array 130 is greater than the row height, the angle between the major axis and the column in the microstructure unit array 130 is between 45° and 90°. For example, the row height of some microstructure units 131 in the microstructure unit array 130 can be equal to the column width. In this case, which is the row and which is the column can be determined according to the actual situation, and it can be considered that the angle between its major axis and the column in the microstructure unit array 130 is less than or equal to 45°.

[0062] In embodiments of this application, a plurality of rotated microstructure units 131 constitute a microstructure unit array 130. The distribution of the microstructure unit array 130 is as follows: Figure 10 As shown. It needs to be explained that... Figure 10 A schematic diagram of the distribution of microstructure units 131 after random angle adjustment is also shown.

[0063] Figure 11 An illustrative projection of a row of rotated microstructural units 131 is shown. The maximum height difference between the surfaces of the aforementioned curvature-adjusted microstructural units is significantly reduced compared to the maximum height difference between the surfaces of the microstructural units 121 before curvature adjustment. Specifically, the multiple rotated microstructural units 131 in... Figure 11 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.

[0064] The diffraction effect of the diffuser plate provided in this embodiment is as follows: Figure 12 As shown, the interference fringes are further suppressed, the diffraction pattern is more uniform, and the diffusion effect is good.

[0065] Another aspect of this application provides a display device 200. This display device may include any of the diffuser plate 100 and light source 210 described in the above embodiments.

[0066] Figure 13 This is a schematic block diagram of a display device according to an embodiment of this application.

[0067] 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 140 and a microstructure unit array 120. The image light emitted by the light source 210 enters the diffuser plate body 140 from the microstructure unit array 130 and is then projected out from the diffuser plate body 140.

[0068] The diffuser plate body 140 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 arrayed on the second side of the diffuser plate body 140. Image light emitted by the light source 210 enters from the second side of the microstructure unit array 130, is modulated inside the microstructure unit array 130, enters the diffuser plate body 140, and is then projected out from the first side of the diffuser plate body 140.

[0069] 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.

[0070] 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.

[0071] 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. Diffusion plate, characterized in that 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, each column of which has a column width that is a random value; and wherein the microstructure units are rotated about a face-type axis that is perpendicular to and passes through the center point of the bottom surface of the microstructure units, each of the microstructure units has a random rotation angle about the face-type axis thereof, the face-type of the microstructure units has a curvature, the face-type of the microstructure units has a major axis and a minor axis that are perpendicular to each other in the plane perpendicular to the face-type axis thereof, and the angle between the major axis and the column is a random value; the product of the square of the column width of the microstructure units and the curvature of the microstructure units in the direction of the column width at the vertex thereof is a first constant value. The row height of the microstructure units is greater than or equal to the column width, and the angle between the major axis and the column is less than or equal to 45°.

2. The diffusion plate of claim 1, wherein The column width of the microstructure units is greater than the row height, and the angle between the major axis and the column is between 45° and 90°.

3. The diffusion plate of claim 1, wherein The minimum value of the column width is greater than or equal to 0.6 times the maximum value of the column width.

4. The diffusion plate of claim 1, wherein The column width is between 15 μm and 100 μm.

5. The diffusion plate of claim 4, wherein The row height of each row in the array of microstructure units is a random value.

6. The diffusion plate according to any one of claims 1 to 5, characterized by The minimum value of the row height is greater than or equal to 0.6 times the maximum value of the row height.

7. The diffusion plate of claim 6, wherein The row height is between 15 μm and 100 μm.

8. The diffusion plate of claim 7, wherein The projection of the boundary of the rows on the diffusion plate body is a straight line, and the projection of the boundary of the columns on the diffusion plate body is a straight line.

9. The diffusion plate of claim 1, wherein The rows are perpendicular to the columns, and adjacent rows are contiguous, and adjacent columns are contiguous.

10. The diffusion plate of claim 9, wherein In the direction perpendicular to the diffusion plate body, the height difference between the vertices of the plurality of microstructure units is less than or equal to 1.5 μm.

11. The diffusion plate of claim 1, wherein The product of the square of the row height of the microstructure units and the curvature of the microstructure units in the direction of the row height at the vertex thereof is a second constant value.

12. The diffusion plate of claim 1, wherein After the light passes through the diffusion plate, a rectangular diffraction image is formed.

13. The diffusion plate of claim 1, wherein The diffusion plate comprises:

14. A display device, characterized by the diffusion plate according to any one of claims 1 to 13; and a light source arranged on one side of the diffusion plate for emitting a light beam to be diffused to the diffusion plate. The light source comprises a laser light source. ​ 15. The display device of claim 14, wherein, ​

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