Backlight source and display device

Abstract

A backlight source and a display device. In the backlight source, a light source (100) includes a light-emitting unit (110); a light-transmitting substrate (200) is located on the light-emitting side of the light source (100); a first lens group (300) includes a plurality of first lenses (310) and is located on the light-emitting side of the light-transmitting substrate (200); and a second lens group (400) includes a plurality of second lenses (410) and is located on the light-incident side of the light-transmitting substrate (200). The maximum dimensions of the first lens (310) and the second lens (410) in a direction parallel to the light-transmitting substrate (200) are respectively a first dimension (D1) and a second dimension (D2), the first dimension (D1) is larger than the second dimension (D2), the orthographic projection of the second lens (410) on the light-transmitting substrate (200) overlaps with the outline of the orthographic projection of the first lens (310) on the light-transmitting substrate (200) or is located within the interval between the orthographic projections of adjacent first lenses (310) on the light-transmitting substrate (200); the maximum dimension of each light-emitting unit (110) in a direction parallel to the light-transmitting substrate (200) is a third dimension (D3), the ratio of the second dimension (D2) to the third dimension (D3) is 0.2 to 0.5, and the ratio of the second dimension (D2) to the first dimension (D1) is 0.04 to 0.2.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a backlight source and a display device. Background Art

[0002] Virtual reality (VR) display is becoming a hot field. In order to reduce the graininess of the display image, the display screen resolution generally needs to be greater than 1500ppi, or even higher, such as greater than 3000ppi. For display screens with such a high pixel density (ppi), its pixel transmittance will be severely reduced. For example, the pixel transmittance of display screens used in virtual reality display devices is generally less than 2%, which will directly lead to an increase in backlight brightness and even an increase in the overall power consumption of the module. Summary of the Invention

[0003] The present disclosure provides a backlight source and a display device.

[0004] The backlight provided by the present disclosure includes: a light source, a transparent substrate, a first lens group, and a second lens group. The light source includes a plurality of light-emitting units; the transparent substrate is located on the light-emitting side of the light source; the first lens group is located on the light-emitting side of the transparent substrate, and the first lens group includes a plurality of first lenses; the second lens group is located on the light-entering side of the transparent substrate, and the second lens group includes a plurality of second lenses. The maximum dimension of each first lens in a direction parallel to the transparent substrate is a first dimension, and the maximum dimension of each second lens in a direction parallel to the transparent substrate is a second dimension, the first dimension is greater than the second dimension, and the orthographic projection of at least one second lens on the transparent substrate overlaps with the outline of the orthographic projection of at least one first lens on the transparent substrate or is located within the interval between the orthographic projections of adjacent first lenses on the transparent substrate; the maximum dimension of each light-emitting unit in a direction parallel to the transparent substrate is a third dimension, the ratio of the second dimension to the third dimension is 0.2 to 0.5, and the ratio of the second dimension to the first dimension is 0.04 to 0.2.

[0005] For example, according to an embodiment of the present disclosure, the ratio of the first size to the pitch between adjacent light emitting units is 0.7 to 1.3.

[0006] For example, according to an embodiment of the present disclosure, the distance between the optical axis of at least one first lens and the optical axis of the second lens closest to the optical axis of the at least one first lens is less than 15 micrometers.

[0007] For example, according to an embodiment of the present disclosure, the multiple first lenses are arranged in a one-to-one correspondence with the multiple light-emitting units, and the orthographic projection of each first lens on the light-transmitting substrate overlaps with the orthographic projection of at least two second lenses on the light-transmitting substrate. The first lenses with overlapping orthographic projections, the light-transmitting substrate and the at least two second lenses constitute an optical structure, and the distance between at least one light-emitting unit and the focal plane of the corresponding optical structure is not greater than 50 microns.

[0008] For example, according to an embodiment of the present disclosure, the plurality of first lenses are closely arranged, and the plurality of second lenses are closely arranged.

[0009] For example, according to an embodiment of the present disclosure, the shape of the orthographic projection of each first lens on the light-transmitting substrate includes a hexagon, there is basically no gap between the orthographic projections of adjacent first lenses on the light-transmitting substrate, and the orthographic projection of at least one second lens on the light-transmitting substrate overlaps with the outline of the orthographic projections of at least two first lenses on the light-transmitting substrate.

[0010] For example, according to an embodiment of the present disclosure, the shape of the orthographic projection of each first lens on the transparent substrate includes a circle, and the gap between the orthographic projections of any adjacent first lenses on the transparent substrate overlaps with the orthographic projection of at least one second lens on the transparent substrate.

[0011] For example, according to an embodiment of the present disclosure, the shape of the orthographic projection of each first lens on the light-transmitting substrate includes a circle, a gap is provided between the orthographic projections of any adjacent first lenses on the light-transmitting substrate, and the orthographic projection of at least one second lens on the light-transmitting substrate is completely located within the gap.

[0012] For example, according to an embodiment of the present disclosure, the geometric center of the gap falls within the orthographic projection of a second lens on the light-transmitting substrate, and the orthographic projection of the second lens on the light-transmitting substrate is completely located within the gap.

[0013] For example, according to an embodiment of the present disclosure, the geometric center of the gap falls within the orthographic projection of a second lens on the transparent substrate, and the orthographic projection of the second lens on the transparent substrate overlaps or is tangent to the orthographic projection of the first lens on the transparent substrate.

[0014] For example, according to an embodiment of the present disclosure, each light emitting unit is configured to emit white light.

[0015] For example, according to an embodiment of the present disclosure, at least one light-emitting unit includes sub-light-emitting units of different colors.

[0016] For example, according to an embodiment of the present disclosure, the ratio of the thickness of the light-transmitting substrate to the maximum dimension of the second lens in a direction perpendicular to the light-transmitting substrate is 8-20.

[0017] For example, according to an embodiment of the present disclosure, the first lens includes a plano-convex lens, the second lens includes a plano-convex lens, and the planes of the first lens and the second lens are both facing the light-transmitting substrate.

[0018] For example, according to an embodiment of the present disclosure, both the first lens and the second lens include spherical lenses.

[0019] For example, according to an embodiment of the present disclosure, the ratio of the curvature radius of the first lens to the first size is 0.4-0.6, and the ratio of the first size to the maximum size of the first lens in a direction perpendicular to the light-transmitting substrate is 1.5-6.

[0020] For example, according to an embodiment of the present disclosure, the ratio of the curvature radius of the second lens to the second size is 0.4-0.6, and the ratio of the second size to the maximum size of the second lens in a direction perpendicular to the light-transmitting substrate is 2-7.

[0021] For example, according to an embodiment of the present disclosure, the refractive index of the first lens is greater than the refractive index of the light-transmitting substrate.

[0022] For example, according to an embodiment of the present disclosure, the refractive index of the second lens is greater than the refractive index of the light-transmitting substrate.

[0023] For example, according to an embodiment of the present disclosure, the angle of light emitted by the backlight source is ±α degrees, and α is not greater than 5.

[0024] An embodiment of the present disclosure provides a display device, comprising a display panel and any of the above-mentioned backlight sources, wherein the display panel is located on the light-emitting side of the backlight source.

[0025] For example, according to an embodiment of the present disclosure, the display panel includes a plurality of sub-pixels, the maximum size of each sub-pixel in a direction parallel to the light-transmitting substrate is a fourth size, and the distance between adjacent first lenses is smaller than the fourth size. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0027] Figure 1 Light path diagram of a display device using VR technology.

[0028] Figure 2 This is a partial structural diagram of a collimated backlight source.

[0029] Figure 3It is a schematic diagram of a partial cross-sectional structure of a backlight source provided according to an embodiment of the present disclosure.

[0030] Figure 4A This is a schematic diagram of a partial planar structure of a light source in a backlight source provided according to an embodiment of the present disclosure in one example.

[0031] Figure 4B and Figure 4C Schematic diagram of the planar structure of a light-emitting unit in different examples.

[0032] Figure 5 for Figure 3 The light path diagram of a first lens, a second lens and a transparent substrate in the backlight source is shown.

[0033] Figure 6 FIG. 1 is a light path diagram of a first lens, a second lens, and a transparent substrate in a backlight source in another example.

[0034] Figure 7 This is a light path diagram when only the first lens is set in the backlight source.

[0035] Figure 8 Based on Figure 3 The light path diagram of the optical structure composed of a first lens, a transparent substrate and multiple second lenses in the backlight source is shown.

[0036] Figure 9 for Figure 7 The structure shown is Figure 8 The structure shown is a graph showing the relationship between the convergence angles corresponding to light-emitting units of different sizes at different sizes.

[0037] Figure 10 This is a graph showing the effect of the air gap between the second lens and the light source on the focusing angle and uniformity of the backlight source.

[0038] Figure 11 is a graph showing the effect of the air gap between the second lens and the light source on the light efficiency of the backlight source.

[0039] Figure 12 The graph is a graph showing the effect of thickness variation of the light-transmitting substrate on the collimation angle and brightness uniformity of the backlight source when the second lens has different second sizes.

[0040] Figure 13 This is a graph showing the effect of the thickness change of the transparent substrate on the light effect when the second lens has different second sizes.

[0041] Figure 14 The graph is a graph showing the effect of thickness variation of the light-transmitting substrate on the collimation angle and brightness uniformity of the backlight source when the second lens has different second sizes.

[0042] Figure 15 This is a graph showing the effect of the thickness change of the transparent substrate on the light effect when the second lens has different second sizes.

[0043] Figure 16 for Figure 7 Brightness distribution diagram when only the first lens is provided in the backlight source shown.

[0044] Figure 17A for Figure 3 An orthographic projection diagram of a portion of the first lens, a portion of the second lens, and a portion of the light-emitting unit in an example of a backlight source is shown.

[0045] Figure 17B for Figure 3 The orthographic projection relationship diagram of part of the first lens, part of the second lens and part of the light-emitting unit of the backlight source in another example is shown.

[0046] Figure 17C for Figure 3 The diagram shows an orthographic projection relationship of a portion of the first lens, a portion of the second lens, and a portion of the light-emitting unit of the backlight source in another example.

[0047] Figure 18 for Figure 17A Brightness distribution diagram of the backlight shown.

[0048] Figure 19 for Figure 3 The orthographic projection relationship diagram of part of the first lens, part of the second lens and part of the light-emitting unit of the backlight source in another example is shown.

[0049] Figure 20 for Figure 19 Brightness distribution diagram of the backlight shown.

[0050] Figure 21 for Figure 3 The relationship between the focusing angle and brightness of the backlight source is shown.

[0051] Figure 22 A partial structural diagram of a display device provided according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0052] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0053] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the ordinary meaning understood by a person of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are simply used to distinguish different components. The terms "include" or "comprises" and similar terms mean that the element or object preceding the term includes the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The characteristics of "parallel," "perpendicular," and "same" used in the embodiments of this disclosure include the characteristics of "parallel," "perpendicular," and "same" in the strict sense, as well as "approximately parallel," "approximately perpendicular," and "approximately the same" that include certain errors, taking into account the errors associated with the measurement of specific quantities (for example, the limitations of the measurement system), and represent the acceptable deviation range for a specific value determined by a person of ordinary skill in the art. For example, "approximately" can mean within one or more standard deviations, or within 10% or 5% of the stated value. When the number of a component is not specifically specified below in the embodiments of this disclosure, it means that the component can be one or more, or can be understood as at least one. "At least one" means one or more, and "a plurality" means at least two.

[0054] Figure 1 This is an optical path diagram of a display device using VR technology. Figure 1 As shown, the display device includes a display panel and a backlight source 001 and a lens group 002 located on the light-emitting side of the display panel and the backlight source 001. For example, the lens group 002 can adopt a folded light path (Pancake).

[0055] During the research, the inventors of the present application found that: Figure 1 The pixel transmittance of the display panel shown is only 2%. For the lens group 002 using the Pancake optical path, the light efficiency is about 20%. The brightness required for human viewing is at least 100 nits. The backlight brightness required is 100÷0.2÷0.02=25000nit. Therefore, the required backlight brightness is 2 to 5 times that of ordinary backlight, resulting in higher power consumption of the backlight source.

[0056] A display device that uses pixel-level dimming technology, such as adding a dimming lens at the bottom of the pixel, deflects light that originally entered the non-transparent area and was blocked into the translucent area, such as the opening of the black matrix, through the dimming lens, thereby increasing the amount of light transmitted and solving the above-mentioned problem of high backlight power consumption.

[0057] However, by simulating the change in gain with the height of the dimming lens, using the example of setting the maximum thickness of the dimming lens to 3.5 microns, using a plano-convex lens, and using a refractive index of 1.8, we found that when the backlight's light output angle is 20 degrees, the maximum gain does not exceed 120%; when the backlight's light output angle is 10 degrees, the maximum gain can reach 150%. This shows that only when the backlight has high collimation, such as when the light output angle is within the range of ±5 degrees, can the overall light efficiency of a display device using pixel-level dimming technology be significantly improved.

[0058] Figure 2 This is a partial structural diagram of a collimated backlight source. Figure 2 As shown, the collimated light source includes a light source plate 035, a diffusion structure 034 located on the light-emitting side of the light source plate 035, a light conversion structure 033, a light-collecting structure 032, and a collimating structure 031. For example, the light source plate 035 includes a plurality of light sources, a reflective layer, and a driving circuit board. For example, a light mixing distance OD is provided between the light source and the diffusion structure 034. For example, the light conversion structure 033 includes a quantum dot conversion layer, such as converting blue light into red light or green light. For example, the diffusion structure 034 may include a diffuser plate. For example, the collimating structure 031 may include a prism layer, a brightness enhancement film, and other structures. As shown in FIG. Figure 2 As shown, the total thickness of the collimating structure 031 to the diffusing structure 034 is about 0.97 mm, the light mixing distance on the light-emitting side of the light source plate 035 is about 0.5 mm, and the thickness of the light source plate 035 is about 0.22 mm. Therefore, the thickness of the collimated backlight source is about 1.7 mm.

[0059] The embodiments of the present disclosure provide a backlight source and a display device. The backlight source includes a light source, a transparent substrate, a first lens group, and a second lens group. The light source includes a plurality of light-emitting units; the transparent substrate is located on the light-emitting side of the light source; the first lens group is located on the light-emitting side of the transparent substrate, and the first lens group includes a plurality of first lenses; the second lens group is located on the light-incident side of the transparent substrate, and the second lens group includes a plurality of second lenses. The maximum dimension of each first lens in a direction parallel to the transparent substrate is a first dimension, and the maximum dimension of each second lens in a direction parallel to the transparent substrate is a second dimension. The first dimension is greater than the second dimension. The orthographic projection of at least one second lens on the transparent substrate overlaps with the outline of the orthographic projection of at least one first lens on the transparent substrate or is located within the interval between the orthographic projections of adjacent first lenses on the transparent substrate. The maximum dimension of each light-emitting unit in a direction parallel to the transparent substrate is a third dimension. The ratio of the second dimension to the third dimension is 0.2 to 0.5, and the ratio of the second dimension to the first dimension is 0.04 to 0.2.

[0060] In the backlight source provided by the present disclosure, by respectively arranging a first lens and a second lens on both sides of a light-transmitting substrate, and setting the relative position relationship between the first lens and the second lens, the first size of the first lens, the second size of the second lens, and the third size relationship of the light-emitting unit, the backlight source can have high collimation and high uniformity.

[0061] The backlight source and display device provided by the embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0062] Figure 3 It is a schematic diagram of a partial cross-sectional structure of a backlight source provided according to an embodiment of the present disclosure. Figure 4A This is a schematic diagram of a partial planar structure of a light source in a backlight source provided according to an embodiment of the present disclosure in one example.

[0063] like Figure 3 and Figure 4A As shown, the backlight includes a light source 100, a transparent substrate 200, a first lens group 300, and a second lens group 400. The light source 100 includes a plurality of light emitting units 110. For example, the plurality of light emitting units 110 may be arranged in an array along the X direction and the Z direction.

[0064] like Figure 3 As shown, the transparent substrate 200 is located on the light-emitting side of the light source 100. For example, the transparent substrate 200 can be a solid substrate or a hollow substrate. For example, an air gap is provided between the transparent substrate 200 and the light source 100.

[0065] like Figure 3 As shown, the first lens group 300 is located on the light-emitting side of the transparent substrate 200, e.g., the first lens group 300 is located on the side of the transparent substrate 200 away from the light source 100. The first lens group 300 includes a plurality of first lenses 310. The second lens group 400 is located on the light-incident side of the transparent substrate 200, e.g., the second lens group 400 is located between the transparent substrate 200 and the light source 100. The second lens group 400 includes a plurality of second lenses 410.

[0066] like Figure 3As shown, the maximum dimension of each first lens 310 in a direction parallel to the transparent substrate 200 is a first dimension D1, and the maximum dimension of each second lens 410 in a direction parallel to the transparent substrate 200 is a second dimension D2, with the first dimension D1 being greater than the second dimension D2. The transparent substrate 200 includes a principal plane perpendicular to the Y-direction, and the direction parallel to the transparent substrate 200 may be a direction parallel to the principal plane. For example, the number of second lenses 410 is greater than the number of first lenses 310. The first dimension D1 of the first lens 310 may be the aperture of the first lens 310, and the second dimension D2 of the second lens 410 may be the aperture of the second lens 410. For example, the orthographic projection of the first lens 310 on the transparent substrate 200 may be circular, with the first dimension D1 being the diameter of the circle. The orthographic projection of the second lens 410 on the transparent substrate 200 may also be circular, with the second dimension D2 being the diameter of the circle. For example, the orthographic projection of the first lens 310 on the transparent substrate 200 may also have other shapes, such as a polygon such as a quadrilateral, pentagon, hexagon, or octagon, and the first dimension D1 may be the length of the longest diagonal of the polygon. For example, the orthographic projection of the second lens 320 on the transparent substrate 200 may also have other shapes, such as a polygon such as a quadrilateral, pentagon, hexagon, or octagon, and the second dimension may be the length of the longest diagonal of the polygon. The present disclosure takes the example of each first lens having strictly equal maximum dimensions in a direction parallel to the transparent substrate, i.e., each first dimension being strictly equal. Taking into account process errors, the first dimensions of different first lenses may differ to a certain extent, such as the certain difference being no greater than 10% of the first dimension. The present disclosure takes the example of each second lens having strictly equal maximum dimensions in a direction parallel to the transparent substrate, i.e., each second dimension being strictly equal. Taking into account process errors, the second dimensions of different second lenses may differ to a certain extent, such as the certain difference being no greater than 10% of the second dimension.

[0067] like Figure 3 As shown, the orthographic projection of at least one second lens 410 on the transparent substrate 200 overlaps with the outline of the orthographic projection of at least one first lens 310 on the transparent substrate 200 or is located within the interval between the orthographic projections of adjacent first lenses 310 on the transparent substrate 200. For example, the outline of the orthographic projection of each first lens 310 on the transparent substrate 200 overlaps with the orthographic projections of multiple second lenses 410 on the transparent substrate 200. For example, the orthographic projection of the center of at least one first lens 310 on the transparent substrate 200 falls within the orthographic projection of the second lens 410 on the transparent substrate 200. For example, the orthographic projection of at least one first lens 310 on the transparent substrate 200 overlaps with the orthographic projections of at least two second lenses 410 on the transparent substrate 200.

[0068] like Figure 3 and Figure 4A As shown, the maximum dimension of each light-emitting unit 110 in a direction parallel to the light-transmitting substrate 200 is the third dimension D3, the ratio of the second dimension D2 to the third dimension D3 is 0.2 to 0.5, and the ratio of the second dimension D2 to the first dimension D1 is 0.04 to 0.2. For example, the third dimension D3 can be the maximum dimension of the light-emitting area of ​​the light-emitting unit 110 in a direction parallel to the light-transmitting substrate. For example, the shape of the light-emitting area can be a polygon, and the third dimension D3 can be the length of the diagonal of the light-emitting area. The present disclosure takes the maximum dimension of each light-emitting unit in a direction parallel to the light-transmitting substrate, that is, each third dimension is strictly equal, as an example. Taking into account process errors, there may be a certain difference in the third dimensions of different light-emitting units, such as the certain difference is not greater than 10% of the third dimension.

[0069] In some examples, such as Figure 3 As shown, the angle of the light emitted by the backlight source is ±α degrees, and α is not greater than 5. For example, α can be 5, or 4.9, or 4.8, or 4.7, or 4.6, or 4.5, etc. For example, the light uniformity of the backlight source is not less than 83.3%. For example, the light uniformity of the backlight source is not less than 85%.

[0070] In the backlight source provided by the present disclosure, by respectively arranging a first lens and a second lens on both sides of a light-transmitting substrate, arranging the second lens to overlap with the contour edge of the first lens or overlap with the gap between adjacent first lenses, and setting the relationship between the first size of the first lens, the second size of the second lens, and the third size of the light-emitting unit, the backlight source can have a high collimation within a light output angle of ±5° and a high uniformity of not less than 83.3%.

[0071] Relative to Figure 2 The backlight source shown in the present invention adopts the first lens group as a collimating structure, realizes the diffusion and focusing functions through the second lens group, and reduces the light mixing distance through the cooperation of the first lens group and the second lens group, which is beneficial to reducing the thickness of the backlight source. For example, the thickness of the backlight source is reduced to 1.5 mm, or even below 1.1 mm, and the thickness reduction can reach 40%.

[0072] The backlight source with high collimation provided by the present disclosure is applied to Figure 1 The display device shown is matched with a display panel with pixel-level dimming function, which is beneficial to improving the brightness of the display device, such as increasing the brightness gain multiplier by 1.5, reducing the power consumption of the display device, such as reducing power consumption by 30%, and improving the overall device battery life.

[0073] For example, Figure 3As shown, the ratio of the second dimension D2 to the third dimension D3 is 1 / 5 to 1 / 3, and the ratio of the second dimension D2 to the first dimension D1 is 1 / 15 to 1 / 9. For example, the ratio of the second dimension D2 to the third dimension D3 is 0.24 to 0.4, and the ratio of the second dimension D2 to the first dimension D1 is 0.05 to 0.15.

[0074] For example, Figure 3 As shown, each first lens 310 has the same shape and size, and each second lens 410 has the same shape and size. For example, each first lens 310 has the same refractive index, and each second lens 410 has the same refractive index.

[0075] For example, Figure 3 As shown, the second lens 410 can be made on the surface of the transparent substrate 200. However, the present invention is not limited thereto. In other examples, the second lens can be made on other substrates and then bonded to the surface of the transparent substrate.

[0076] In some examples, such as Figure 3 As shown, the distance between the optical axis of at least one first lens 310 and the optical axis of the second lens 410 closest to the optical axis of the at least one first lens 310 is less than 15 microns. For example, the optical axis of the first lens 310 and the optical axis of the second lens 410 are both perpendicular to the light-transmitting substrate 200, such as extending along the Y direction.

[0077] For example, Figure 3 As shown, the distance between the optical axis of at least one first lens 310 and the optical axis of the second lens 410 is less than 10 microns. For example, the distance between the optical axis of at least one first lens 310 and the optical axis of the second lens 410 is less than 5 microns. For example, the optical axis of at least one first lens 310 coincides with the optical axis of the second lens 410. For example, the optical axis of each first lens 310 coincides with the optical axis of the corresponding second lens 410, which helps ensure that the vertex of the output spectrum corresponds to the 0° position.

[0078] In some examples, such as Figure 3 and Figure 4A As shown, the ratio of the first dimension D1 to the pitch P of adjacent light-emitting units 110 is 0.7 to 1.3. The pitch P of adjacent light-emitting units 110 may refer to the length of the line connecting the centers of adjacent light-emitting units 110. For example, the ratio of the first dimension D1 to the pitch P of adjacent light-emitting units 110 is 0.9 to 1.2. For example, the ratio of the first dimension D1 to the pitch P of adjacent light-emitting units 110 is 0.8 to 1.1. For example, the ratio of the first dimension D1 to the pitch P of adjacent light-emitting units 110 is 0.95 to 1.05. For example, the first dimension D1 is equal to the pitch of adjacent light-emitting units 110 to improve the light efficiency and ensure the brightness uniformity of the light-emitting surface.

[0079] For example, Figure 3 As shown, adjacent light emitting units 110 may refer to adjacent light emitting units 110 arranged along the X direction, or may refer to adjacent light emitting units 110 arranged along a direction perpendicular to the XY plane.

[0080] In some examples, such as Figure 3 As shown, the plurality of first lenses 310 are disposed in a one-to-one correspondence with the plurality of light emitting units 110. For example, the number of the plurality of first lenses 310 is the same as the number of the plurality of light emitting units 110.

[0081] In some examples, such as Figure 3 As shown, the first lens 310 includes a plano-convex lens, the second lens 410 includes a plano-convex lens, and the planes of the first lens 310 and the second lens 410 are both facing the light-transmitting substrate 200 .

[0082] In some examples, such as Figure 3 and Figure 4A As shown, each light-emitting unit 110 is configured to emit white light. For example, each light-emitting unit 110 includes a single-color LED 111 and a color conversion layer 112. The color conversion layer 112 surrounds the LED 111, converting the non-white light emitted by the LED 111 into white light through the color conversion layer 112. For example, the single-color LED 111 may be a blue LED. For example, the color conversion layer 112 may include a quantum dot material or a color conversion material such as a phosphor. For example, the shape of the light-emitting unit 110 may be rectangular, and the third dimension D3 may be the diagonal dimension of the light-emitting area formed by the light emitted by the color conversion layer 112. For example, the distance M between the edge of the color conversion layer 112 and the edge of the LED 111 may be 15 microns. Of course, the shape of the light-emitting area is not limited to a rectangle. For example, it can also be a regular shape such as a circle, an ellipse, a triangle, a rhombus, a pentagon, a hexagon, an octagon, or other irregular shapes, such as a rounded polygon or a shape with curved edges. The third dimension may be the diameter of a circle, the major axis of an ellipse, the longest diagonal of other polygons, etc.

[0083] Figure 4B and Figure 4C Schematic diagram of the planar structure of a light-emitting unit in different examples.

[0084] For example, Figure 4B and Figure 4C As shown, at least one light emitting unit 110 includes sub-light emitting units 101 of different colors. Each light emitting unit 110 includes a light emitting diode 101 of a different color to emit white light. For example, each light emitting unit 110 may include a red light emitting diode, a green light emitting diode, and a blue light emitting diode. For example, the red light emitting diode, the green light emitting diode, and the blue light emitting diode may be as follows Figure 4B The tiling settings shown can also be Figure 4C For example, the third dimension D3 of the light emitting unit 110 can be the maximum dimension of the light emitting area 102 formed by the red light emitting diode, the green light emitting diode and the blue light emitting diode. For example, the shape of the light emitting area 102 can be rectangular, and the third dimension D3 is the length of the diagonal of the rectangle. Of course, the present disclosure is not limited to this. Different color light emitting units can also be arranged perpendicular to the Figure 4B As shown in the XZ plane arrangement, the shapes of the light-emitting areas of the sub-light-emitting units of different colors can be the same, and their orthographic projections on the XZ plane coincide. The third dimension is the maximum dimension of one of the light-emitting areas, such as the diagonal dimension, circular diameter, etc.

[0085] For example, Figure 4B and Figure 4C The distance S between adjacent light emitting diodes 101 in the same light emitting unit 110 is greater than Figure 4A The distance M shown is, for example, 75 micrometers. Thus, light emitting units with different structures may have different sizes, and the size of the light emitting unit emitting white light is an influencing factor of the sizes of the first lens and the second lens.

[0086] For example, Figures 3 to 4C As shown, for light-emitting units with the same luminous efficiency, the larger the size of the light-emitting unit, the larger the corresponding pitch (Pitch) to meet the same backlight brightness. The backlight brightness Lbl of the backlight source satisfies the relationship: Lbl = N*Le*Ae / (P*P), where N is the required number of light-emitting units, Le is the brightness of the light-emitting unit, Ae is the light-emitting area of ​​the light-emitting unit, and P is the pitch between adjacent light-emitting units. It can be seen that the larger P, the smaller the required N, and for light-emitting units with the same luminous efficiency, the corresponding power consumption will be lower.

[0087] Figure 5 for Figure 3 The light path diagram of a first lens, a second lens and a transparent substrate in the backlight source is shown.

[0088] In some examples, such as Figure 3 and Figure 5 As shown, the first lens 310 and the second lens 410 both include plano-convex lenses, each of which includes a spherical surface.

[0089] For example, Figure 5 As shown, the first lens 310 may be in direct contact with the light-transmitting substrate 200 .

[0090] For example, Figure 5As shown, the aperture D1 of the first lens 310 can be determined as the pitch of adjacent light-emitting units based on power consumption, backlight brightness, and the optoelectronic characteristics of the light-emitting units. Then, the collimated light is traced in reverse from the center to the aperture edge of the first lens 310 so that each light ray falls within the aperture D2 of the second lens 410. The aperture D2 of the second lens 410 is determined based on the refractive index n2, curvature radius R, aperture D1, arch height H of the first lens 310, thickness T2 of the transparent substrate 200, refractive index n3, and refractive index n1 of the medium other than the first lens 310 and the transparent substrate 200.

[0091] For example, Figure 5 As shown, the angle between the light incident on the edge of the first lens 310 and the tangent of the curved surface of the first lens 310 is θ1, the light is perpendicular to the surface of the transparent substrate 200, the angle between the light and the normal to the curved surface of the first lens 310 is θ2, and the light is refracted during the process of entering the first lens 310, and the refraction angle is θ3. The angle between the light incident on the first lens 310 and the normal to the surface of the transparent substrate 200 is θ5, and the light is refracted during the process of entering the transparent substrate 200, and the refraction angle is θ6. The distance between the position where the light is incident on the first lens 310 and the surface of the transparent substrate 200 close to the first lens 310 is h, and twice the distance between this position and the highest point of the first lens 310 in a direction parallel to the transparent substrate 200 is D. Based on the geometric relationship and Snell's law, the following relationship can be obtained:

[0092] θ1=arccos[(D / 2) / R] (1)

[0093] θ2=π / 2-θ1 (2)

[0094] θ3=arcsin[(n1*sinθ2) / n2] (3)

[0095] θ4=θ1+θ3 (4)

[0096] θ5=π / 2-θ4 (5)

[0097] θ6=arcsin[(n2*sinθ5) / n3] (6)

[0098] W1=(D1-D) / 2 (7)

[0099] h=H-{R-[R 2 -(D / 2) 2 ] -2} (8)

[0100] W2=h*tanθ5 (9)

[0101] W3=T2*tanθ6 (10)

[0102] D2=D1-2*(W1+W2+W3) (11)

[0103] Substituting the relevant parameters in the above-mentioned equations (1)-(10) into equation (11), a value of D2 can be obtained. For the collimated light ray tracing incident on different positions of the first lens 310, multiple D2 values ​​can be obtained, among which the largest D2 value is the aperture value that can be adopted by the second lens 410. The aperture value is the aperture D2 of the second lens 410 corresponding to the refractive index n2, curvature radius R, aperture D1, arch height H, thickness T2 and refractive index n3 of the transparent substrate 200 of the first lens 310, and the refractive index n1 of the medium other than the first lens 310 and the transparent substrate 200 as a set of parameters.

[0104] For example, Figure 5 As shown, the first lens 310 and the transparent substrate 200 can be made of two materials, and the refractive indices n2 and n3 are fixed values. Assuming that the medium outside the first lens 310 and the transparent substrate 200 is air, the refractive index n1 is also fixed. In this case, by adjusting the thickness T2 of the transparent substrate 200, the radius of curvature R, and the dome height H of the first lens 310, a minimum D2 value can be obtained. This D2 value can serve as the minimum value that can be selected for the aperture D2 of the second lens 410. For example, when adjusting the thickness T2 of the transparent substrate 200, the radius of curvature R, and the dome height H of the first lens 310, it is also necessary to consider the impact of the aperture of the second lens on the collimation and brightness uniformity of the backlight, as well as the processing technology of the second lens. Therefore, the aperture of the second lens may be equal to or greater than the above minimum value.

[0105] Figure 6 FIG. 1 is a light path diagram of a first lens, a second lens, and a transparent substrate in a backlight source in another example.

[0106] For example, Figure 6 As shown, a spacer layer 320 is disposed between the first lens 310 and the light-transmitting substrate 200 . Figure 6 The backlight shown is Figure 5 The difference of the backlight shown is that a spacer layer 320 is provided between the first lens 310 and the transparent substrate 200 . For example, the first lens 310 can be made on the spacer layer 320 , and the spacer layer 320 is attached to the surface of the transparent substrate 200 .

[0107] For example, Figure 6As shown, the aperture D1 of the first lens 310 can be determined as the pitch of adjacent light-emitting units based on power consumption, backlight brightness, and the optoelectronic characteristics of the light-emitting units. Then, the collimated light is traced in reverse from the center to the aperture edge of the first lens 310 so that each light ray falls within the aperture D2 of the second lens 410. The aperture D2 of the second lens 410 is determined based on the refractive index n2, curvature radius R, aperture D1, arch height H of the first lens 310, thickness T1 and refractive index n4 of the spacer layer 320, thickness T2 and refractive index n3 of the transparent substrate 200, and refractive index n1 of the medium other than the first lens 310 and the transparent substrate 200.

[0108] For example, Figure 6 As shown, the angle between a light ray incident on the edge of the first lens 310 and the tangent to the curved surface of the first lens 310 is θ1. This light ray is perpendicular to the surface of the spacer layer 320. The angle between this light ray and the normal to the curved surface of the first lens 310 is θ2. This light ray is refracted as it enters the first lens 310 at an angle of θ3. The angle between a light ray incident on the first lens 310 and the normal to the surface of the spacer layer 320 is θ5. This light ray is refracted as it enters the spacer layer 320 at an angle of θ6. The angle between a light ray incident on the surface of the transparent substrate 200 is θ6. This light ray is refracted as it enters the transparent substrate 200 at an angle of θ7. The arch height of the first lens 310 is H. The distance between the point where the light ray enters the first lens 310 and the surface of the spacer layer 320 adjacent to the first lens 310 is h. The distance between this point and the highest point of the first lens 310, parallel to the transparent substrate 200, is twice the distance D. According to the geometric relationship and Snell's law, the following relationship can be obtained:

[0109] θ1=arccos[(D / 2) / R] (1')

[0110] θ2=π / 2-θ1 (2')

[0111] θ3=arcsin[(n1*sinθ2) / n2] (3')

[0112] θ4=θ1+θ3 (4')

[0113] θ5=π / 2-θ4 (5')

[0114] θ6=arcsin[(n2*sinθ5) / n4] (6')

[0115] θ7=arcsin[(n4*sinθ6) / n3] (7')

[0116] W1=(D1-D) / 2 (8')

[0117] h=H-{R-[R 2 -(D / 2) 2 ] -2} (9')

[0118] W2=h*tanθ5 (10')

[0119] W4=T1*tanθ6 (11')

[0120] W3=T2*tanθ7 (12')

[0121] D2=D1-2*(W1+W2+W3+W4) (13')

[0122] Substituting the relevant parameters in the above-mentioned equations (1')-(12') into equation (13') can obtain a value of D2. For the collimated light ray tracing incident on different positions of the first lens 310, multiple D2 values ​​can be obtained, among which the largest D2 value is the aperture value that can be adopted by the second lens 410. The aperture value is the aperture D2 of the second lens 410 corresponding to a set of parameters including the refractive index n2, curvature radius R, aperture D1, arch height H, thickness T2 and refractive index n3 of the transparent substrate 200, thickness T1 and refractive index n4 of the spacer layer 320, and refractive index n1 of the medium other than the first lens 310 and the transparent substrate 200.

[0123] For example, Figure 5 As shown, the first lens 310, the spacer layer 320, and the transparent substrate 200 can be made of three materials. The refractive indices n2, n4, and n3 are fixed values. Assuming that the medium outside the first lens 310 and the spacer layer 320 is air, the refractive index n1 is also fixed. In this case, by adjusting the thickness T1 of the spacer layer 320, the thickness T2 of the transparent substrate 200, the radius of curvature R, and the dome height H of the first lens 310, a minimum D2 value can be obtained. This D2 value can serve as the minimum value that can be selected for the aperture D2 of the second lens 410. For example, when adjusting the thickness T1 of the spacer layer 320, the thickness T2 of the transparent substrate 200, the radius of curvature R, and the dome height H of the first lens 310, it is also necessary to consider the impact of the aperture of the second lens on the collimation and brightness uniformity of the backlight source, as well as the processing technology of the second lens. Therefore, the aperture of the second lens may be equal to or greater than the above minimum value.

[0124] Therefore, in the above Figure 5 and Figure 6In the example shown, by adjusting various parameters based on comprehensive consideration of various factors, the ratio of the second size of the second lens to the third size of the light-emitting unit is 0.2-0.5, and the ratio of the second size of the second lens to the first size of the first lens is 0.04-0.2.

[0125] Figure 7 This is a light path diagram when only the first lens is set in the backlight source. Figure 8 Based on Figure 3 The light path diagram of the optical structure composed of a first lens, a transparent substrate and multiple second lenses in the backlight source is shown.

[0126] For example, Figure 7 As shown, when the first lens 310 is disposed on one side of the transparent substrate 200 and the second lens 410 is not disposed on the other side of the transparent substrate 200, the focal plane F1 has a large deviation from the ideal focal plane F0 due to the existence of field curvature. In addition, in this structure, the aperture angle α1 is small, and the distance between the ideal focal plane F0 and the object side principal surface QH1, such as the focal length f1, is large. In order to reduce Figure 7 The focal length of the backlight source shown can be achieved by setting another lens on the other side of the transparent substrate where the first lens is not set, and the number of the lenses is the same as the number of the first lenses, and the aperture of the lens is equivalent to the aperture of the first lens.

[0127] For example, Figure 8 As shown, relative to Figure 7 The backlight shown in the figure can reduce the offset distance between the focal plane F2 and the ideal focal plane F0 by disposing a second lens 410 on the other side of the transparent substrate 200. Therefore, the optical structure composed of the second lens 410, the transparent substrate 200 and the first lens 310 can correct the field curvature so that each position of the focal surface F2 is as close as possible to the ideal focal plane F0, which can achieve collimated emission for larger-sized light-emitting units; and the focal surface F2 has multiple peaks close to the ideal focal plane F0, which has a light deflection effect. For example, in addition to allowing the light source point located on the optical axis to collimate the emitted light, it can also allow other light source points off-axis and located near the peaks of the focal surface F2 close to the ideal focal plane F0 to collimate the emitted light. While improving the collimation of the light emitted from the first lens, it can also achieve a scattering function, homogenize the energy distribution, and improve and ensure uniformity.

[0128] For example, Figure 8 As shown, compared with setting lenses with the same number and equivalent aperture as the first lenses on the other side of the light-transmitting substrate where the first lenses are not set, the backlight source provided by the present disclosure sets multiple second lenses with smaller apertures on the other side of the light-transmitting substrate. While achieving short focus, it can also disperse the light, improve the uniformity of the light output of the backlight source, and enable the light emitted by the light-emitting unit with an angle of more than ±80° to be incident on the corresponding first lens.

[0129] For example, Figure 8 As shown, compared to Figure 7 The backlight source shown in the figure reduces the focal length f2 between the ideal focal plane F0 and the object side principal surface QH2 by setting the second lens 410, that is, the optical focal length of the optical structure composed of the second lens 410, the transparent substrate 200 and the first lens 310 is increased. For example, the optical focal length of the first lens 310 is 1 / f01, and the optical focal length of the second lens 410 is 1 / f02. The optical focal length of the optical structure satisfies 1 / f=1 / f01+1 / f02, so as to achieve a short-focus effect. For example, the object side principal surface QH2 of the optical structure is pulled toward the light source, thereby increasing the aperture angle α2 and enhancing the focusing ability of the optical structure, which is beneficial to improving the light efficiency while compressing the mixed light distance between the light source and the second lens, thereby reducing the thickness of the backlight source.

[0130] Figure 9 for Figure 7 The structure shown is Figure 8 The structure shown is a graph showing the relationship between the convergence angles corresponding to light-emitting units of different sizes at different sizes.

[0131] For example, Figure 9 As shown, line L1, line L2 and line L3 all represent curves of a structure in which only the first lens is provided in the backlight source, and line L4, line L5 and line L6 represent curves of a structure in which only the first lens is provided in the backlight source. Figure 3 In the curves of the structure of the first and second lenses shown, the curvature radius of the first lens corresponding to lines L1 and L4 is 0.3 mm, the curvature radius of the first lens corresponding to lines L2 and L5 is 0.6 mm, and the curvature radius of the first lens corresponding to lines L3 and L6 is 0.9 mm. Each of the above curves corresponds to a first lens.

[0132] For example, Figure 9 As shown in the figure, when a single first lens has the same aperture, for example, when the curvature radius of the first lens is 0.6 mm, it can be seen that when the L2 line and the L5 line meet the convergence angle of less than 5°, the diagonal size of the light-emitting unit required in the backlight source with only the first lens cannot exceed 145 microns, while the diagonal size of the light-emitting unit required in the backlight source with the first lens and the second lens is not greater than 330 microns. For example, when selecting the light-emitting unit, you can choose Figures 4B to 4C The light emitting unit shown can also be selected Figure 4A The light-emitting unit shown; when selecting Figures 4B to 4C In the case of the light-emitting unit shown in FIG. 1 , since the spacing S is about 75 microns, in a backlight source provided with only the first lens, the actual light-emitting width of the light-emitting unit is less than 70 microns, while in a backlight source provided with the first lens and the second lens, the actual light-emitting width of the light-emitting unit can reach more than 200 microns. Figure 3 The backlight source of the first lens and the second lens shown can use a larger light-emitting unit while achieving high collimation, which is beneficial to reducing power consumption. The above-mentioned convergence angle can also be called the collimation angle.

[0133] In some examples, such as Figure 3 and Figure 5 As shown, the radius of curvature R of the first lens 310 is equal to 0.4 to 0.6 of the first dimension D1, and the ratio of the first dimension D1 to the maximum dimension H of the first lens 310 in the direction perpendicular to the transparent substrate 200 is 1.5 to 6. For example, the ratio of the first dimension D1 to the maximum dimension H of the first lens 310 in the direction perpendicular to the transparent substrate 200 is 1.6 to 4. For example, the ratio of the first dimension D1 to the maximum dimension H of the first lens 310 in the direction perpendicular to the transparent substrate 200 is 1.7 to 3. For example, the ratio of the first dimension D1 to the maximum dimension H of the first lens 310 in the direction perpendicular to the transparent substrate 200 is 1.8 to 5. For example, the ratio of the first dimension D1 to the maximum dimension H of the first lens 310 in the direction perpendicular to the transparent substrate 200 is 1.9 to 2.1. For example, the first dimension D1 (aperture D1) of the first lens 310 is twice the radius of curvature R. For example, the first dimension D1 is twice the thickness H of the first lens 310.

[0134] For example, Figure 3 and Figure 5 As shown, in order to improve the light energy utilization rate of the light emitting unit 110 at a large angle, it is necessary to reduce the focal length f of the optical structure composed of the first lens 310, the transparent substrate 200 and the second lens 410. The focal length f is determined by the relationship 1 / f=1 / f10+1 / f20. For example, Figure 5 and Figure 6 In the example shown, when determining the aperture D2 of the second lens 410, the curvature radius R of the first lens 310 can be optimized as much as possible. For example, considering process factors, the curvature radius R of the first lens 310 and the aperture D1 need to satisfy the relationship: R ≥ D1 / 2. On the other hand, according to the focal length formula of a plano-convex lens, f = R / Δn, where Δn represents the refractive index difference between the first lens 310 and another medium (such as air), the focal length of the first lens 310 is proportional to the curvature radius R. In order to reduce the focal length f of the above-mentioned optical structure, the first lens 310 should have a focal length as small as possible, and the curvature radius R of the first lens 310 should also be a small value. Therefore, considering both process factors and short-focus factors, the curvature radius of the first lens is as close to half of the aperture as possible.

[0135] For example, Figure 5 As shown, the maximum size H (such as arch height or center thickness), curvature radius R and aperture D1 of the first lens 310 satisfy the relationship: R 2=(RH) 2 +(D1 / 2) 2 Based on the numerical relationship between the curvature radius R and the aperture D1, we can determine that the thickness H of the first lens is roughly half the aperture D1. D1 / H is an indicator of the processing capability of the first lens.

[0136] In some examples, such as Figure 3 and Figure 5 As shown, the radius of curvature of the second lens 410 is equal to 0.4 to 0.6 of the second dimension D2, and the ratio of the second dimension D2 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 2 to 7. For example, the ratio of the second dimension D2 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 2.1 to 4. For example, the ratio of the second dimension D2 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 2.5 to 3. For example, the ratio of the second dimension D2 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 2.8 to 5. For example, the ratio of the second dimension D2 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 4.5 to 6. For example, the second dimension D2 of the second lens 410 is twice the radius of curvature. For example, the second dimension D2 is twice the thickness of the second lens 410, which helps to reduce the focal length of the second lens. Similarly, referring to the first lens, the setting of the numerical relationship between the curvature radius, aperture, and thickness of the second lens provided by the present disclosure needs to comprehensively consider the process factors and short focus factors.

[0137] In some examples, such as Figure 3 and Figure 8As shown, the orthographic projection of each first lens 310 on the transparent substrate 200 overlaps with the orthographic projection of at least two second lenses 410 on the transparent substrate 200. The first lenses 310, the transparent substrate 200, and the at least two second lenses 410 with overlapping orthographic projections form an optical structure. The distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 50 microns. For example, the distance between each light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 50 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 45 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 40 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 35 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 30 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 25 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 20 microns. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 15 micrometers. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 10 micrometers. For example, the distance between at least one light-emitting unit 110 and the focal plane of its corresponding optical structure is no greater than 5 micrometers. For example, the light-emitting unit can be located on the focal plane of its corresponding optical structure.

[0138] Figure 10 This is a graph showing the effect of the air gap between the second lens and the light source on the focusing angle and uniformity of the backlight source. Figure 11 is a graph showing the effect of the air gap between the second lens and the light source on the light efficiency of the backlight source.

[0139] For example, Figure 10 and Figure 11 As shown, line L11 represents the relationship curve between the air gap and the convergence angle of the backlight source, line L12 represents the relationship curve between the air gap and the uniformity of the backlight source, and position F is the focus of the optical structure composed of the first lens, the transparent substrate and the second lens.

[0140] For example, Figure 10 and Figure 11 As shown, taking the refractive index of the first lens as 1.7, the refractive index of the transparent substrate as 1.5, the refractive index of the second lens as 1.6, the maximum size of the light-emitting unit as 268 microns, and the ratio of the aperture to the center thickness of the first lens as 2 as an example, we can obtain Figure 10 and Figure 11The air gap has an impact on the convergence angle, uniformity, and light efficiency of the backlight. For example, the air gap can be no larger than 45 microns.

[0141] For example, Figure 10 and Figure 11 As shown, when the air gap fluctuates within a range of 50 microns near the focal plane, the convergence angle of the backlight source remains basically unchanged, such as around 5 degrees, and the surface uniformity of the light emitted by the backlight source changes in a wave-like manner; the luminous efficiency of the backlight source is basically maintained at around 70%.

[0142] In some examples, such as Figure 3 As shown, the ratio of the thickness of the transparent substrate 200 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 8 to 20. For example, the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 may be the center thickness or the dome height of the second lens 410. For example, the ratio of the thickness of the transparent substrate 200 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 10 to 15. For example, the ratio of the thickness of the transparent substrate 200 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 9 to 12. For example, the ratio of the thickness of the transparent substrate 200 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 11 to 16. For example, the ratio of the thickness of the transparent substrate 200 to the maximum dimension of the second lens 410 in a direction perpendicular to the transparent substrate 200 is 14 to 18.

[0143] In some examples, such as Figure 3 As shown, the refractive index of the first lens 310 is greater than the refractive index of the transparent substrate 200. For example, the greater the refractive index of the first lens is, the thinner the transparent substrate can be, which is conducive to achieving a lighter and thinner backlight source.

[0144] In some examples, such as Figure 3 As shown, the refractive index of the second lens 410 is greater than the refractive index of the light-transmitting substrate 200. For example, the refractive index of the first lens 310 is greater than the refractive index of the second lens 410.

[0145] Figure 12 The graph is a graph showing the effect of thickness variation of the light-transmitting substrate on the collimation angle and brightness uniformity of the backlight source when the second lens has different second sizes. Figure 13 This is a graph showing the effect of the thickness change of the transparent substrate on the light effect when the second lens has different second sizes. Figure 14 The graph is a graph showing the effect of thickness variation of the light-transmitting substrate on the collimation angle and brightness uniformity of the backlight source when the second lens has different second sizes. Figure 15 This is a graph showing the effect of the thickness change of the transparent substrate on the light effect when the second lens has different second sizes. Figure 12 and Figure 13 The third size of the light-emitting units corresponding to the curves shown is the same. Figure 14 and Figure 15 The third size of the light-emitting units corresponding to the curves shown is the same, and Figure 12 and Figure 13 They respectively correspond to different third sizes of the light-emitting units.

[0146] For example, Figure 12 and Figure 13 As shown, the light-emitting unit is Figure 4A Taking the structure shown, the diagonal length of the light-emitting unit is 268 μm, the refractive index of the first lens is 1.7, the refractive index of the transparent substrate is 1.5, the refractive index of the second lens is 1.6, the curvature radius of the first lens is 693 μm, the aperture to arch height ratio of the first lens is 2, the aperture of the first lens is 1.13 to 1.21 mm, and the pitch of the light-emitting unit is 1.13 to 1.21 mm as an example, the range of the D2 value can be calculated by referring to the above-mentioned relationship formulas (1)-(11), or relationship formulas (1')-(13'). L21 represents the collimation curve when the aperture of the second lens is 85 microns, L22 represents the brightness uniformity curve when the aperture of the second lens is 85 microns, L31 represents the collimation curve when the aperture of the second lens is 100 microns, L32 represents the brightness uniformity curve when the aperture of the second lens is 100 microns, L41 represents the luminous efficiency curve when the aperture of the second lens is 85 microns, and L51 represents the luminous efficiency curve when the aperture of the second lens is 100 microns. For example, when the aperture of the second lens is 85 and 100 microns, and the thickness of the transparent substrate is greater than 600 microns, the convergence angle of the backlight source is less than 5° and the luminous efficiency is approximately 70%. However, the brightness uniformity of the backlight source gradually decreases when the thickness of the transparent substrate is greater than 650 microns. Therefore, when the aperture of the second lens is 85 and 100 microns, a transparent substrate thickness of 650 microns can simultaneously meet the requirements of a collimation angle less than 5°, a luminous efficiency of approximately 70%, and a brightness uniformity greater than 80%.

[0147] For example, Figure 14 and Figure 15 As shown, the light-emitting unit is Figure 4B or Figure 4CTaking the structure shown, and the diagonal length of the light-emitting unit is 500 μm, the refractive index of the first lens is 1.7, the refractive index of the transparent substrate is 1.5, the refractive index of the second lens is 1.6, the curvature radius of the first lens is 1270 μm, the aperture to arch height ratio of the first lens is 2, the aperture of the first lens is 1.8 to 3 mm, and the pitch of the light-emitting unit is 2.16 to 3 mm as an example, the range of the D2 value can be calculated by referring to the above-mentioned relationship formulas (1)-(11), or relationship formulas (1')-(13'). L61 represents the collimation curve when the aperture of the second lens is 120 microns, L62 represents the brightness uniformity curve when the aperture of the second lens is 120 microns, L71 represents the collimation curve when the aperture of the second lens is 140 microns, L72 represents the brightness uniformity curve when the aperture of the second lens is 140 microns, L81 represents the luminous efficiency curve when the aperture of the second lens is 120 microns, and L91 represents the luminous efficiency curve when the aperture of the second lens is 140 microns. For example, when the apertures of the second lens are 120 microns and 140 microns, and the thickness of the transparent substrate is greater than 1150 microns, the convergence angle of the backlight source is less than 5°, and the luminous efficiency is approximately 70% to 75%. However, the brightness uniformity of the backlight source gradually decreases when the thickness of the transparent substrate exceeds 1150 microns. Therefore, when the aperture of the second lens is 140 microns and the thickness of the transparent substrate is 1150 microns, the collimation angle can be less than 5°, the light efficiency is about 70% to 75%, and the brightness uniformity is greater than 80%.

[0148] For example, Figure 3 As shown, when the diagonal length of the light-emitting unit 110 is 268 μm, the maximum thickness of the second lens 410 is 0.05 mm, the thickness of the transparent substrate 200 is 0.65 mm, the thickness of the first lens 310 is 0.46-0.63 mm, and the overall thickness of the backlight source is 1.68-1.82 mm.

[0149] For example, Figure 3 As shown, when the diagonal length of the light-emitting unit 110 is 120 μm, the maximum thickness of the second lens 410 is 0.02 mm, the thickness of the transparent substrate 200 is 0.2 mm, the thickness of the first lens 310 is 0.15-0.2 mm, and the overall thickness of the backlight source is 0.95-1.05 mm.

[0150] Figure 16 for Figure 7 Brightness distribution diagram when only the first lens is provided in the backlight source shown. Figure 16 The upper left corner shows the brightness distribution on the light-emitting surface of the backlight, the lower left corner shows the brightness curve when Y = 0, and the right side shows the brightness curve when X = 0. Both curves show the brightness fluctuations on the entire light-emitting surface.

[0151] For example, Figure 16 and Figure 7 As shown in the figure, when there is a gap between adjacent first lenses, the light emitted from the gap between the first lenses is not refracted by the first lenses. This gap will reduce the surface uniformity of the backlight. For example, when the projection of the first lenses is circular, even if adjacent circles are closely arranged, there will still be a gap between the circles. This gap will cause the surface uniformity of the backlight to be reduced.

[0152] Figure 17A for Figure 3 An orthographic projection diagram of a portion of the first lens, a portion of the second lens, and a portion of the light-emitting unit in an example of a backlight source is shown. Figure 18 for Figure 17A Brightness distribution diagram of the backlight shown.

[0153] In some examples, such as Figure 17A As shown, the plurality of first lenses 310 are closely arranged, and the plurality of second lenses 410 are closely arranged, which is beneficial to improving the surface uniformity of the backlight source.

[0154] In some examples, such as Figure 17A As shown, the orthographic projection of each first lens 310 on the transparent substrate includes a circular shape, and the gap between the orthographic projections of any adjacent first lenses 310 on the transparent substrate overlaps the orthographic projection of at least one second lens 410 on the transparent substrate. For example, the gap between the orthographic projections of adjacent first lenses 310 on the transparent substrate overlaps the orthographic projections of the plurality of second lenses 410 on the transparent substrate. For example, the orthographic projection of at least one second lens 410 on the transparent substrate is completely located within the gap. For example, the plurality of second lenses 410 include three types of second lenses 410, each of which has a different positional relationship with the first lens 310. For example, the orthographic projection of a first type of second lens 410 is completely located within the orthographic projection of the first lens 310, the orthographic projection of a second type of second lens 410 overlaps the orthographic projection of an edge of the first lens 310, and the orthographic projection of a third type of second lens 410 does not overlap the orthographic projection of the first lens 310 at all. For example, adjacent first lenses 310 may refer to three first lenses 310 whose orthographic projections touch at their edges.

[0155] By using the second lens to fill the gaps between the first lenses, the light passing through the gaps between adjacent first lenses will be deflected by the second lens, such as deflected toward the collimating direction, which is beneficial to improving the surface uniformity of the light emitted by the backlight source.

[0156] For example, Figure 18 As shown, relative to Figure 16 As shown in the figure, the brightness fluctuation of the brightness curve of the backlight source when X=0 and Y=0 is smaller, and the surface uniformity of the backlight source is improved.

[0157] In some examples, such as Figure 17A As shown, the geometric center of the gap falls within the orthographic projection of the second lens 410 on the transparent substrate, which helps further improve the surface uniformity of the backlight. For example, the geometric center of the gap is located within the orthographic projection of a second lens 410 on the transparent substrate, and the second lens 410 is completely located within the gap. For example, the optical axis of the second lens 410 passes through the geometric center of the gap that overlaps with the second lens 410.

[0158] Figure 17B for Figure 3 The orthographic projection relationship diagram of part of the first lens, part of the second lens and part of the light-emitting unit of the backlight source in another example is shown. Figure 17B The example shown is the same as Figure 17A In the example shown, the apertures of the first lenses are the same, and the apertures of the second lenses are different. Figure 17B The second lens shown has an aperture greater than Figure 17A The aperture of the second lens is shown.

[0159] In some examples, such as Figure 17B As shown, the shape of the orthographic projection of each first lens 310 on the transparent substrate includes a circle, the gap between the orthographic projections of any adjacent first lenses 310 on the transparent substrate overlaps with the orthographic projection of at least one second lens 410 on the transparent substrate, the geometric center of the above gap falls within the orthographic projection of one second lens 410 on the transparent substrate, and the orthographic projection of the above second lens 410 on the transparent substrate overlaps with the orthographic projection of the first lens 310 on the transparent substrate. Figure 17B Only one second lens whose orthographic projection overlaps with the gap is illustrated, and other second lenses are omitted.

[0160] For example, Figure 17B As shown, three adjacent first lenses 310 are tangent to each other, and the orthographic projection of the second lens 410 may overlap with the orthographic projection of at least one of the three first lenses 310. For example, the orthographic projection of the second lens 410 may overlap with the orthographic projections of the three first lenses 310, but the present invention is not limited thereto. The orthographic projection of the second lens may also overlap with the orthographic projections of one or two first lenses.

[0161] Figure 17C for Figure 3 The diagram shows an orthographic projection relationship of a portion of the first lens, a portion of the second lens, and a portion of the light-emitting unit of the backlight source in another example. Figure 17C The example shown is the same as Figure 17A and Figure 17B In the example shown, the apertures of the first lenses are the same, and the apertures of the second lenses are different. Figure 17C The second lens shown has an aperture greater than Figure 17AThe aperture of the second lens is smaller than Figure 17B The aperture of the second lens is shown.

[0162] In some examples, such as Figure 17C As shown, the shape of the orthographic projection of each first lens 310 on the transparent substrate includes a circle, the gap between the orthographic projections of any adjacent first lenses 310 on the transparent substrate overlaps with the orthographic projection of at least one second lens 410 on the transparent substrate, the geometric center of the above gap falls within the orthographic projection of one second lens 410 on the transparent substrate, and the orthographic projection of the above second lens 410 on the transparent substrate is tangent to the orthographic projection of the first lens 310 on the transparent substrate. Figure 17C Only one second lens whose orthographic projection is tangent to the orthographic projection of the first lens is illustrated, and other second lenses are omitted.

[0163] For example, Figure 17C As shown, three adjacent first lenses 310 are tangent to each other, and the orthographic projection of the second lens 410 may be tangent to the orthographic projection of at least one of the three first lenses 310. For example, the orthographic projection of the second lens 410 may be tangent to the orthographic projections of the three first lenses 310, but the present invention is not limited thereto. The orthographic projection of the second lens may also be tangent to the orthographic projections of one or two first lenses.

[0164] Figure 19 for Figure 3 The orthographic projection relationship diagram of part of the first lens, part of the second lens and part of the light-emitting unit of the backlight source in another example is shown. Figure 20 for Figure 19 Brightness distribution diagram of the backlight shown.

[0165] In some examples, such as Figure 19 As shown, the orthographic projections of each first lens 310 on the transparent substrate include a hexagonal shape, with substantially no gap between the orthographic projections of adjacent first lenses 310 on the transparent substrate. The orthographic projection of at least one second lens 410 on the transparent substrate overlaps the orthographic projections of at least two first lenses 310 on the transparent substrate. For example, adjacent edges of adjacent first lenses 310 with hexagonal orthographic projections touch to achieve a close arrangement with multiple second lenses of smaller apertures. This can break the light-concentrating effect of the first lenses, achieving a short focus while improving light extraction efficiency and light uniformity from the same first lens, thereby enhancing the uniformity of the surface light source of the backlight.

[0166] For example, Figure 20 As shown, relative to Figure 18 As shown in the figure, the brightness fluctuation of the brightness curve of the backlight source at X=0 and Y=0 is smaller. By further reducing the gap between the first lenses, the surface uniformity of the backlight source can be further improved.

[0167] For example, Figure 17A and Figure 19 As shown, the shape of the orthographic projection of the second lens 410 on the transparent substrate can be a circle, but is not limited thereto, and can also be a polygon such as a hexagon or an octagon.

[0168] For example, Figure 17A and Figure 19 As shown, the plurality of second lenses 410 may be arranged in an array along the X direction and the Z direction. However, the present invention is not limited thereto. For example, two adjacent rows of second lenses arranged along the Z direction may be staggered, which is beneficial for further reducing the gap between adjacent second lenses.

[0169] Figure 21 for Figure 3 The relationship between the convergence angle and brightness of the backlight is shown in the figure. Figure 21 As shown, K1 and K2 represent the relationship between the brightness and convergence angle of the backlight source in two different directions. The two different directions can be Figure 4A The X and Z directions are shown, and the spectra in these two different directions basically overlap. For example, the brightness of the backlight source emitting light in two different directions at ±5 degrees is approximately 150,000 nits, and the maximum brightness of the backlight source is close to 1,000,000 nits. For example, each backlight source has a peak. For example, by arranging the light source in the backlight source near the focal plane of the optical structure, it is possible to avoid the backlight source emitting a multi-peak spectrum, which is conducive to achieving the effect of an ultra-high collimation surface light source.

[0170] Figure 22 FIG. 1 is a partial structural diagram of a display device according to another embodiment of the present disclosure. Figure 22 As shown, the display device includes the backlight source 20 in any of the above examples and a display panel 10 located on the light-emitting side of the backlight source 20 .

[0171] In some examples, such as Figure 22 As shown, the display panel 10 includes a plurality of sub-pixels 11. The maximum dimension of each sub-pixel parallel to the light-transmitting substrate 200 is a fourth dimension, and the distance between adjacent first lenses 310 is less than the fourth dimension. By setting the distance between adjacent first lenses to be less than the sub-pixel size, the effect of the gaps between the first lenses in the backlight source on light uniformity and the display panel's display image is reduced.

[0172] For example, Figure 22As shown, the display panel 10 may be a liquid crystal display panel, including an array substrate and an opposing substrate disposed oppositely, and a liquid crystal layer located between the array substrate and the opposing substrate. For example, the sub-pixel 11 may include a pixel electrode and a common electrode. The maximum size of the sub-pixel in a direction parallel to the transparent substrate may be the maximum size of the light emitting area of ​​the sub-pixel. For example, the light emitting area may be an area defined by a black matrix disposed on the opposing substrate, and the light emitting area may be parallel to the light emitting surface of the backlight source.

[0173] There are a few points to note:

[0174] (1) The drawings of the embodiments of the present disclosure only involve structures related to the embodiments of the present disclosure, and other structures can refer to general designs.

[0175] (2) In the absence of conflict, features in the same embodiment and different embodiments of the present disclosure may be combined with each other.

[0176] The foregoing description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. The scope of protection of the present disclosure is determined by the appended claims.

Claims

1. A backlight source, comprising: a light source comprising a plurality of light-emitting units; a light-transmitting substrate, located on the light-emitting side of the light source; a first lens group, located on the light-emitting side of the light-transmitting substrate, the first lens group including a plurality of first lenses; The second lens group is located on the light incident side of the light-transmitting substrate, and the second lens group includes a plurality of second lenses. The maximum dimension of each first lens in a direction parallel to the light-transmitting substrate is a first dimension, the maximum dimension of each second lens in a direction parallel to the light-transmitting substrate is a second dimension, the first dimension is greater than the second dimension, and the orthographic projection of at least one second lens on the light-transmitting substrate overlaps with the outline of the orthographic projection of at least one first lens on the light-transmitting substrate or is located within the interval between the orthographic projections of adjacent first lenses on the light-transmitting substrate; The maximum size of each light emitting unit in a direction parallel to the transparent substrate is a third size, a ratio of the second size to the third size is 0.2-0.5, and a ratio of the second size to the first size is 0.04-0.

2.

2. The backlight source according to claim 1, wherein: The ratio of the first size to the pitch between adjacent light emitting units is 0.7 to 1.

3.

3. The backlight source according to claim 1, wherein: A distance between an optical axis of the at least one first lens and an optical axis of the second lens closest to the optical axis of the at least one first lens is less than 15 micrometers.

4. The backlight source according to claim 1, wherein: The multiple first lenses are arranged in a one-to-one correspondence with the multiple light-emitting units, and the orthographic projection of each first lens on the light-transmitting substrate overlaps with the orthographic projection of at least two second lenses on the light-transmitting substrate. The first lenses with overlapping orthographic projections, the light-transmitting substrate, and the at least two second lenses constitute an optical structure, and a distance between at least one light-emitting unit and a focal plane of the corresponding optical structure is no more than 50 microns.

5. The backlight source according to claim 1, wherein: The plurality of first lenses are closely arranged, and the plurality of second lenses are closely arranged. The backlight source according to claim 5 , wherein: The shape of the orthographic projection of each first lens on the transparent substrate includes a hexagon, there is basically no gap between the orthographic projections of adjacent first lenses on the transparent substrate, and the orthographic projection of at least one second lens on the transparent substrate overlaps with the outline of the orthographic projections of at least two first lenses on the transparent substrate.

7. The backlight source according to claim 5, wherein: The orthographic projection of each first lens on the transparent substrate has a circular shape, and a gap between the orthographic projections of any adjacent first lenses on the transparent substrate overlaps with the orthographic projection of at least one second lens on the transparent substrate.

8. The backlight source according to claim 5, wherein: The orthographic projection of each first lens on the transparent substrate has a circular shape, a gap is provided between the orthographic projections of any adjacent first lenses on the transparent substrate, and the orthographic projection of at least one second lens on the transparent substrate is completely located within the gap.

9. The backlight source according to claim 7, wherein: The geometric center of the gap falls within the orthographic projection of a second lens on the light-transmitting substrate, and the orthographic projection of the second lens on the light-transmitting substrate is completely located within the gap.

10. The backlight source according to claim 7, wherein: The geometric center of the gap falls within the orthographic projection of a second lens on the transparent substrate, and the orthographic projection of the second lens on the transparent substrate overlaps or is tangent to the orthographic projection of the first lens on the transparent substrate.

11. The backlight source according to any one of claims 1 to 10, wherein: Each light emitting unit is configured to emit white light.

12. The backlight according to claim 11, wherein: At least one light-emitting unit includes sub-light-emitting units of different colors.

13. The backlight source according to any one of claims 1 to 10, wherein: The ratio of the thickness of the light-transmitting substrate to the maximum dimension of the second lens in a direction perpendicular to the light-transmitting substrate is 8-20.

14. The backlight source according to any one of claims 1 to 10, wherein: The first lens includes a plano-convex lens, the second lens includes a plano-convex lens, and the planes of the first lens and the second lens are both facing the light-transmitting substrate.

15. The backlight according to claim 14, wherein: The first lens and the second lens each include a spherical lens.

16. The backlight according to claim 15, wherein: A ratio of a curvature radius of the first lens to the first size is 0.4 to 0.6, and a ratio of the first size to a maximum size of the first lens in a direction perpendicular to the light-transmitting substrate is 1.5 to 6.

17. The backlight according to claim 15, wherein: A ratio of a curvature radius of the second lens to the second size is 0.4 to 0.6, and a ratio of the second size to a maximum size of the second lens in a direction perpendicular to the light-transmitting substrate is 2 to 7.

18. The backlight according to claim 13, wherein: The refractive index of the first lens is greater than the refractive index of the light-transmitting substrate.

19. The backlight source according to any one of claims 1 to 10, wherein: The refractive index of the second lens is greater than the refractive index of the light-transmitting substrate.

20. The backlight source according to any one of claims 1 to 10, wherein: The angle of the light emitted by the backlight source is ±α degrees, and α is not greater than 5.

21. A display device comprising a display panel and the backlight source according to any one of claims 1 to 20, wherein the display panel is located on a light-emitting side of the backlight source.

22. The display device according to claim 21, wherein The display panel includes a plurality of sub-pixels, the maximum size of each sub-pixel in a direction parallel to the light-transmitting substrate is a fourth size, and the distance between adjacent first lenses is smaller than the fourth size.

Images