Lighting device

Abstract

An embodiment of the invention provides a lighting device, comprising: a light source for emitting a light beam; the Fresnel lens is located on a light path of the light beams and used for converging the light beams; the micro-lens array is located on the light path of the light beam and located on the downstream of the Fresnel lens, and when the light beam passes through the micro-lens array, an illumination light beam is formed to leave the micro-lens array.

Description

Technical Field

[0001] Embodiments of the present invention relate to a lighting device. Background Art

[0002] The spot shape and uniformity of the light beam emitted by the light source of a lighting device often do not match the actual application scenarios. Therefore, there is a need for a lighting device that can process the light beam emitted by the light source to make the spot brightness of the emitted lighting beam uniform and the shape of the spot meet the actual application requirements. Summary of the Invention

[0003] Some embodiments of the present invention provide a lighting device, including: a light source for emitting a light beam; a Fresnel lens located on the optical path of the light beam for converging the light beam; a microlens array located on the optical path of the light beam and downstream of the Fresnel lens, and when the light beam passes through the microlens array, an illumination light beam is formed and leaves the microlens array.

[0004] Based on the above, the lighting device of the present invention can make the light beam emitted by the light source have uniform brightness and shape the light spot of the illumination light beam by using the combination of the Fresnel lens and the microlens array, so as to achieve a better lighting effect. Description of the Drawings

[0005] Figure 1 is a schematic diagram of a lighting device according to an embodiment of the present invention;

[0006] Figure 2A is a top view and a sectional view of a Fresnel lens according to an embodiment of the present invention;

[0007] Figure 2B is a top view and a sectional view of a Fresnel lens according to an embodiment of the present invention;

[0008] Figure 3 is a top view of a microlens array according to an embodiment of the present invention;

[0009] Figure 4A is a light field intensity distribution diagram of an illumination light beam according to an embodiment of the present invention;

[0010] Figure 4B is a light field radiation direction diagram of an illumination light beam according to an embodiment of the present invention. Detailed Description

[0011] Examples will be listed below and described in detail with reference to the accompanying drawings. However, the provided examples are not intended to limit the scope covered by the present invention. In addition, the dimensions of the components in the drawn figures are drawn for convenience of illustration and do not represent the actual component size ratios. Moreover, although terms such as "first" and "second" are used in the text to describe different components and / or film layers, these components and / or film layers should not be limited by these terms. Instead, these terms are only used to distinguish one component or film layer from another. Therefore, the first component or film layer discussed below can be referred to as the second component or film layer without violating the teachings of the examples. For ease of understanding, similar components will be denoted by the same reference signs in the following text.

[0012] In the description of the embodiments of the present invention, the same reference signs and / or words may be used in different examples. These repeated reference signs or words are for the purpose of simplification and clarity and are not used to limit the relationship between each embodiment and / or the described external structure. Furthermore, if the following description of the present invention states that a first feature is formed on or above a second feature, it means that it includes embodiments in which the above-mentioned first feature and the above-mentioned second feature are in direct contact, and also includes embodiments in which additional features are formed between the above-mentioned first feature and the above-mentioned second feature, so that the above-mentioned first feature and the above-mentioned second feature may not be in direct contact. For ease of understanding, similar components will be denoted by the same reference signs in the following text.

[0013] Figure 1 It is a schematic diagram of a lighting device according to an embodiment of the present invention.

[0014] Please refer to Figure 1 . The lighting device 100 includes: a light source 110, a Fresnel lens 120, and a microlens array 130.

[0015] The light source 110 is used to emit a light beam L1. In some embodiments, the light source 110 is a light-emitting diode array or others with similar functions, and the present invention is not limited thereto. In some embodiments, the wavelength range of the light beam L1 is 400 - 700 nm. In some embodiments, the light beam L1 can be a monochromatic light, such as red light, green light, or blue light. In some embodiments, the light beam L1 can be white light. In the present embodiment, the spot of the light beam L1 is circular.

[0016] The Fresnel lens 120 is located on the optical path of the light beam L1 and is used to converge the light beam L1. Compared with a traditional spherical lens, the Fresnel lens divides the lens into a series of theoretically infinite concentric circular patterns (i.e., Fresnel zone), so as to achieve the same optical effect as that of a traditional spherical lens, while reducing the thickness of the lens and lightening the weight of the lens. Therefore, by using the Fresnel lens 120, the thickness of the optical device 100 can be effectively reduced, and the volume of the optical device 100 can be significantly reduced.

[0017] Specifically, the Fresnel lens 120 includes a substrate 122 and a lens structure 124, wherein the lens structure 124 is located on the light-emitting surface of the substrate 122. Therefore, when a light beam is incident on the Fresnel lens 120, it sequentially passes through the substrate 122 and the lens structure 124 to condense the light beam L1.

[0018] In some embodiments, the lens structure 124 can be etched on the substrate 122 in an integrally formed manner. In other embodiments, the lens structure 124 can also be separately fabricated and then adhered to the substrate 122 with optical glue.

[0019] In some embodiments, the material of the Fresnel lens 120 is plastic or a light-transmitting material with similar properties, but the present invention is not limited thereto.

[0020] In some embodiments, the focal length of the Fresnel lens 120 is less than 2 mm.

[0021] In some embodiments, the Fresnel lens 120 has a positive refractive power.

[0022] The structure of the Fresnel lens 120 is described below.

[0023] Figure 2A is a top view and a cross-sectional view of a Fresnel lens according to an embodiment of the present invention. Figure 2B is a top view and a cross-sectional view of a Fresnel lens according to another embodiment of the present invention.

[0024] Please first refer to Figure 2A . The Fresnel lens 120A is Figure 1 an embodiment of the Fresnel lens 120 in []. In the top view of the Fresnel lens 120A, the lens structure 124A includes at least eight concentric rings. In this embodiment, the lens structure 124A includes eight concentric rings, namely concentric rings 124A1 to 124A8.

[0025] In the cross-sectional view along line AA, it can be seen that in each of the concentric rings 124A1 to 124A8, each concentric ring includes a mountain-shaped structure, and the mountain-shaped structure is approximately a right triangle, including a width and a height, which are respectively located on the two sides adjacent to the right angle in the right triangle.

[0026] In this embodiment, the heights of the mountain-shaped structures of each concentric ring 124A1-124A8 are the same, which is h. In addition, the widths of the mountain-shaped structures of each concentric ring 124A1-124A8, namely w1, w2…, w8, decrease from the center of the lens structure 124A towards the outside, that is, w1>w2>…>w8.

[0027] In this embodiment, the maximum width among the widths of the multiple mountain-shaped structures is less than 0.5 mm, that is, the maximum width w1 < 0.5 mm, and the height h among the heights of the multiple mountain-shaped structures is less than or equal to 0.3 mm.

[0028] Thus, the concentric rings in the Fresnel lens 120A in this embodiment all have the same height, and the widths of the mountain-shaped structures decrease from the inside to the outside. Among them, in the lens structure 124A, the height of each concentric ring 124A1-124A8 is less than 0.3 mm, and the width of each concentric ring 124A1-124A8 is less than 0.5 mm.

[0029] Please refer to Figure 2B . The Fresnel lens 120B is Figure 1 Another embodiment of the Fresnel lens 120 in . In the top view of the Fresnel lens 120B, the lens structure 124B includes at least eight concentric rings. In this embodiment, the lens structure 124B includes eight concentric rings, namely concentric rings 124B1 to concentric rings 124B8.

[0030] In the cross-sectional view along line BB, it can be seen that among the concentric rings 124B1 to 124B8, each concentric ring includes a mountain-shaped structure, and the mountain-shaped structure is approximately a right triangle, including a width and a height, which are respectively located on the two sides adjacent to the right angle in the right triangle.

[0031] In this embodiment, the widths of the mountain-shaped structures of each concentric ring 124B1-124B8 are the same, which is w. In addition, the heights of the mountain-shaped structures of each concentric ring 124B1-124B8, namely h1, h2…, h8, increase from the center of the lens structure 124B towards the outside, that is, h1<h2<…<h8.

[0032] In this embodiment, the maximum height among the heights of the multiple mountain-shaped structures is less than 0.3 mm, that is, the maximum height h8 < 0.3 mm, and the width w among the widths of the multiple mountain-shaped structures is less than or equal to 0.5 mm.

[0033] Therefore, the concentric rings in the Fresnel lens 120B in this embodiment all have the same width, and the heights of the mountain-shaped structures increase from the inside to the outside. Among them, in the lens structure 124B, the height of each concentric ring 124B1-124B8 is less than 0.3 mm, and the width of each concentric ring 124B1-124B8 is less than 0.5 mm.

[0034] Thus, by using the Fresnel lens 120A or 120B as shown in Figure 2A or Figure 2B , the light beam L1 emitted by the light source 110 can be converged.

[0035] Please go back to Figure 1 .

[0036] The microlens array 130 is located on the optical path of the light beam L1 and downstream of the Fresnel lens 120. When the light beam L1 passes through the microlens array 130, an illumination light beam L2 is formed and exits the microlens array 130.

[0037] Specifically, the microlens array 130 includes a substrate 134. The microlens array 130 further includes a first microstructure array 132 and a second microstructure array 136. The first microstructure array 132 is located on the incident light surface of the microlens array 130, and the second microstructure array 136 is located on the exit light surface of the microlens array 130. Therefore, the first microstructure array 132 and the second microstructure array 136 are respectively located on opposite side surfaces of the substrate 134.

[0038] In some embodiments, the first microstructure array 132 is bonded to the incident light side surface of the substrate 134 with an optical adhesive, and the second microstructure array 136 is bonded to the exit light side surface of the substrate 134 with an optical adhesive.

[0039] In some embodiments, the material of the microlens array 130 (including the first microstructure array 132, the substrate 134, and the second microstructure array 136) is plastic or a light-transmitting material with similar properties. The present invention is not limited thereto.

[0040] In some embodiments, the first microstructure array 132 and the second microstructure array 136 have the same focal length. Therefore, the light beam L1 passing through the first microstructure array 132 can be directly focused on the second microstructure array 136.

[0041] In some embodiments, the projections of the first microstructure array 132 and the second microstructure array 136 along the optical axis of the light beam L1 have the same shape. Therefore, each microstructure in the first microstructure array 132 has a corresponding microstructure with the same shape in terms of the relative position to the optical axis in the second microstructure array 136. Therefore, when the light beam L1 is incident on the microstructure in the first microstructure array 132, the light beam L1 will also enter the corresponding microstructure in the second microstructure array 132 due to the focal length.

[0042] The following describes the structure of the first microstructure array 132 in the microlens array.

[0043] Figure 3is a top view of a microlens array according to an embodiment of the present invention. Since the projections of the first microstructure array 132 and the second microstructure array 136 along the optical axis of the light beam L1 have the same shape, therefore Figure 3 the shown top view is simultaneously the top view of the first microstructure array 132 and the second microstructure array 136.

[0044] As Figure 3 shown, the surfaces of the first microstructure array 132 and the second microstructure array 136 are covered with a plurality of microstructures 138. In this embodiment, the area of each of the plurality of microstructures 138 is less than 1 / 100 of the total area of the first microstructure array 132 and / or the second microstructure array 136. Thus, it can be ensured that the first microstructure array 132 and the second microstructure array 136 have at least 100 or more microstructures 138, which can effectively homogenize the incident light beam L.

[0045] As Figure 3 shown, each of the microstructures 138 is an irregular polygon. Therefore, when the light beam L1 is incident on variously shaped microstructures 138, due to the different shapes of the microstructures 138, the light beam L1 incident on the first microstructure array 132 and the second microstructure array 136 can be homogenized, and the spot of the illumination light beam L2 passing through the second microstructure array 138 can be shaped.

[0046] Although the plurality of microstructures 138 in the first microstructure array 132 and the second microstructure array 136 are irregular polygons, local regions of the first microstructure array 132 and the second microstructure array 136 have mirror symmetry.

[0047] As Figure 3 shown, in local regions of the first microstructure array 132 and the second microstructure array 136, there are a plurality of mirror symmetry axes. For example, in the line CC, the right region 140A and the left region 140B are mirror symmetric with respect to the line CC. By having a plurality of mirror symmetry axes and a plurality of symmetric regions in local regions of the first microstructure array 132 and the second microstructure array 136, the first microstructure array 132 and the second microstructure array 136 can have partial symmetry, so as to homogenize the light beam L1 incident on the first microstructure array 132 and the second microstructure array 136. At the same time, when designing the first microstructure array 132 and the second microstructure array 136, it is also easier to predict and design the spot shape of the illumination light beam L2 in a simulation manner.

[0048] In some embodiments, the spot of the light beam L1 incident on the first microstructure array 132 is circular, and the spot of the illumination light beam L2 emitted through the second microstructure array 138 is rectangular. Therefore, through the microlens array 130, the incident light beam L1 can be shaped to meet the actual application requirements.

[0049] Figure 4A It is the light field intensity distribution diagram of the illumination beam L1 according to an embodiment of the present invention.

[0050] Please refer to Figure 4A . As Figure 4A shown, the spot shape of the illumination beam L2 along the optical axis direction is rectangular, and the lowest brightness within the rectangular area of the spot of the illumination beam L2 is greater than 80% of the maximum brightness of the spot of the illumination beam L2. Therefore, as Figure 4A shown, as Figure 1 shown, the illumination device 100 can generate an illumination beam L2 with a rectangular spot shape and uniform brightness.

[0051] Figure 4B It is the light field radiation direction diagram of the illumination beam L2 according to an embodiment of the present invention.

[0052] Please refer to Figure 4B . When measuring the light field radiation direction distribution of the illumination beam: L2, as shown in Figure 4, the light output direction is concentrated in the area with a divergence angle between plus and minus 10 degrees, that is, the divergence angle of the illumination beam L2 is less than 20 degrees.

[0053] Therefore, as Figure 1 shown, the illumination device 100 can generate an illumination beam L2 with a small divergence angle, improve the illumination efficiency, and reduce the brightness spillover.

[0054] Based on the above, the illumination device described in the present invention uses the combination of a Fresnel lens and a microlens array, which can make the brightness of the beam emitted by the light source uniform and shape the spot of the illumination beam to achieve a better illumination effect.

Claims

1. A lighting device, characterized in that, Comprising: A light source for emitting a light beam; A Fresnel lens located on the optical path of the light beam for converging the light beam; A microlens array located on the optical path of the light beam and downstream of the Fresnel lens. When the light beam passes through the microlens array, an illumination light beam leaves the microlens array.

2. The lighting device according to claim 1, characterized in that, The light source is a light-emitting diode array.

3. The lighting device according to claim 1, characterized in that, The wavelength range of the light beam is 400 - 700 nm.

4. The lighting device according to claim 1, characterized in that, The Fresnel lens includes a substrate and a lens structure, wherein the lens structure is located on the light-emitting surface of the substrate.

5. The lighting device according to claim 4, characterized in that, Wherein the lens structure includes at least eight concentric rings.

6. The lighting device according to claim 5, characterized in that, Each of the concentric rings includes a mountain-shaped structure. The mountain-shaped structure includes a width and a height. The widths of the mountain-shaped structures of each concentric ring are the same, and the heights of the mountain-shaped structures of each concentric ring increase from the inside out along the center of the lens structure.

7. The lighting device according to claim 6, characterized in that, The maximum height among the heights of the mountain-shaped structures of each concentric ring is less than 0.3 mm, and the width among the widths of the mountain-shaped structures of each concentric ring is less than or equal to 0.5 mm.

8. The lighting device according to claim 5, characterized in that, Each of the concentric rings includes a mountain-shaped structure. The mountain-shaped structure includes a width and a height. The heights of the mountain-shaped structures of each concentric ring are the same, and the widths of the mountain-shaped structures of each concentric ring decrease from the inside out along the center of the lens structure.

9. The lighting device according to claim 8, characterized in that, The height of the mountain-shaped structure of each concentric ring is less than 0.3 mm, and the maximum width among the widths of the mountain-shaped structures of each concentric ring is less than or equal to 0.5 mm.

10. The lighting device according to claim 5, characterized in that, The height of each concentric ring is less than 0.3 mm.

11. The lighting device according to claim 5, characterized in that, The width of each concentric ring is less than 0.5 mm.

12. The lighting device according to claim 1, characterized in that The material of the Fresnel lens is plastic.

13. The lighting device according to claim 1, wherein Wherein the focal length of the Fresnel lens is less than 2 mm.

14. The lighting device according to claim 1, characterized in that, Wherein the microlens array includes a first micro-structure array and a second micro-structure array. The first micro-structure array is located on the light-incident surface of the microlens array, and the second micro-structure array is located on the light-emitting surface of the microlens array.

15. The lighting device according to claim 14, characterized in that, The first micro-structure array and the second micro-structure array have the same focal length.

16. The lighting device according to claim 14, characterized in that, The projections of the first micro-structure array and the second micro-structure array along the optical axis of the light beam have the same shape.

17. The lighting device according to claim 14, characterized in that, The first micro-structure array includes a plurality of micro-structures, and the area of each of the plurality of micro-structures is less than 1 / 100 of the total area of the first micro-structure array.

18. The lighting device according to claim 14, characterized in that, The second micro-structure array includes a plurality of micro-structures, and the area of each of the plurality of micro-structures is less than 1 / 100 of the total area of the second micro-structure array.

19. The lighting device according to claim 14, characterized in that, The first micro-structure array includes a plurality of micro-structures, and each of the plurality of micro-structures is an irregular polygon.

20. The lighting device according to claim 1, characterized in that, Wherein the light spot of the light beam is circular.

21. The lighting device according to claim 1, characterized in that, Wherein the light spot of the illumination light beam is rectangular.

22. The lighting device according to claim 1, characterized in that, Wherein the lowest brightness of the light spot of the illumination light beam is greater than 80% of the maximum brightness of the light spot of the illumination light beam.

23. The lighting device according to claim 1, characterized in that, Wherein the divergence angle of the illumination light beam is less than 20 degrees.

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