Optical module and projector

Abstract

This invention provides an optical module and a projection device using the same. The optical module includes a light source and an optical structure. The light source emits light, and the optical structure is disposed on the light source and receives the light. The optical structure includes a first surface and a second surface. The first surface is configured to deflect light. The second surface is configured to project a predetermined pattern when light passes through it, and the second surface has multiple microstructures, corresponding to the first surface.

Description

Technical Field

[0001] The present invention relates to an optical module, and in particular to an optical module having an optical structure including two surfaces with different functions and a projection device used therein. Prior Art

[0002] Projectors for projecting patterns are widely used in three-dimensional (3D) sensing systems, where patterns are projected through optical elements. However, in existing projectors, in order to project patterns with a large field of view (FOV), the optical element structure must have a large slope, making the optical element manufacturing process more difficult. Furthermore, optical element defects and / or zero-order emission can pose eye safety concerns. Summary of the Invention

[0003] One objective of the present invention is to provide an optical module and a projection device used therein to improve problems encountered by existing projection devices. The provided optical module includes a first surface configured to deflect light and a second surface configured to project a predetermined pattern. This allows the optical module to have a large projection field of view while maintaining a relatively small size.

[0004] One embodiment of the present invention provides an optical module. The optical module includes a light source and an optical structure. The light source is configured to emit light, and the optical structure is disposed on the light source and is configured to receive the light. The optical structure includes a first surface and a second surface. The first surface is configured to deflect light. The second surface is configured to project a predetermined pattern when light passes through the second surface, and the second surface has a plurality of microstructures, wherein the second surface corresponds to the first surface.

[0005] One embodiment of the present invention provides a projection device. The projection device includes at least two of the aforementioned optical modules. The at least two optical modules are disposed adjacent to each other, and predetermined patterns projected by the at least two optical modules are combined to form a design pattern. Simple diagram description

[0006] FIG1 is a schematic diagram of an optical module according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of an optical module according to a variation of the first embodiment of the present invention. FIG. 3 is a schematic diagram of an optical module according to a second embodiment of the present invention. FIG. 4 is a schematic diagram of a projection device including two optical modules according to another embodiment of the present invention. FIG. 5 is a schematic diagram of a design pattern projected by the projection device shown in FIG. 4 . Implementation Method

[0007] The present invention is described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, for ease of understanding and simplicity, the various figures herein depict only at least a portion of the optical module and / or projection device, and that certain components in the figures are not drawn to scale. Furthermore, the number and dimensions of components in the figures are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0008] Throughout the present specification and claims, certain terms are used to refer to specific components. Those skilled in the art will appreciate that equipment manufacturers may refer to the same components by different names. This document does not intend to distinguish between components that have the same function but are named differently. In the following specification and claims, the words "comprise," "include," and "have" are open-ended and should be interpreted as meaning "including, but not limited to..." When used in this specification, the terms "comprise," "include," "contain," and / or "have" specify the presence of the stated features, regions, steps, operations, and / or elements, but do not preclude the presence or addition of one or more other features, regions, steps, operations, elements, and / or combinations thereof.

[0009] When an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or directly connected to the other element or layer, or there may be intervening elements or layers (i.e., indirect connection). Conversely, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers.

[0010] Directional terms used herein, such as "up," "down," "front," "back," "left," and "right," are used solely to refer to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes only and are not intended to limit the present invention.

[0011] The use of ordinal numbers such as "first" and "second" in the specification and claims to modify an element does not, by itself, imply or indicate any prior ordinal number of the element(s), nor does it indicate the order of one element relative to another, or the order of manufacturing methods. Such ordinal numbers are used solely to clearly distinguish a named element from another element with the same name. The claims and the specification may not use the same terminology; thus, the first element in the specification may be the second element in the claims.

[0012] It should be understood that features in several different embodiments may be replaced, reorganized, or mixed to complete other embodiments without departing from the spirit of the present invention.

[0013] Please refer to Figure 1, which is a schematic diagram of an optical module according to a first embodiment of the present invention. As shown in Figure 1, the optical module 100 of the present invention includes a light source 110 and an optical structure 120. The light source 110 is used to emit light L, and the optical structure 120 is disposed on the light source 110 and receives the light L. The light source 110 may include one of a laser diode (LD), a vertical-cavity surface-emitting laser (VCSEL), a light-emitting diode (LED), and a photonic-crystal surface-emitting laser (PCSEL), or the light source 110 may include other suitable light-emitting elements, without limitation. The optical structure 120 includes a first surface S1 and a second surface S2, the second surface S2 corresponding to the first surface S1. The first surface S1 is configured to deflect the light L, and the second surface S2 is configured to project a predetermined pattern PA when the deflected light L passes through the second surface S2. The second surface S2 has a plurality of microstructures 122. For example, the first surface S1 may be formed by a first optical layer OL1 including a deflection element for deflecting light, and the second surface S2 may be formed by a second optical layer OL2 having a plurality of microstructures 122. The first surface S1 may include a bevel, a blazed grating, a prism, or a prism array. The plurality of microstructures 122 on the second surface S2 may constitute a microlens array (MLA), a diffractive optical element (DOE), or a meta-surface. According to an embodiment of the present invention, one or more optical modules 100 may be used in a projection device to project one or more predetermined patterns PA. The projection device may include a flood illuminator, a dot projector, or a combination thereof, and the projection device may be used in, but is not limited to, a three-dimensional sensing system or a vehicle sensing device.

[0014] As shown in FIG1 , the first surface S1 may be disposed between the second surface S2 and the light source 110, and light L is deflected by the first surface S1 before passing through the second surface S2. However, the positions of the first surface S1 and the second surface S2 are not limited to the above and may be interchangeable in other embodiments (not shown). In other words, the second surface S2 may be disposed between the first surface S1 and the light source 110, and light L is deflected by the first surface S1 after passing through the second surface S2.

[0015] According to the embodiment shown in FIG1 , the optical structure 120 may include a substrate SB, with a first surface S1 and a second surface S2 located on opposite sides of the substrate SB. Specifically, the first optical layer OL1 may be disposed on the side of the substrate SB facing the light source 110, that is, on the lower surface of the substrate SB, and the second optical layer OL2 may be disposed on the other side of the substrate SB facing away from the light source 110, that is, on the upper surface of the substrate SB. This allows the first surface S1 to face the light source 110, while the second surface S2 faces away from the light source 110. Light source 110 emits light L, which enters the first surface S1 and is deflected by the first optical layer OL1 on the first surface S1 into deflected light L0. The deflected light L0 then passes through the substrate SB and enters the second optical layer OL2 on the second surface S2, where it is projected as a predetermined pattern PA. However, the structural design of the optical structure 120 is not limited to the above. In other embodiments, the second optical layer OL2 can be disposed on the side of the substrate SB facing the light source 110 so that the second surface S2 faces the light source 110, and the first optical layer OL1 can be disposed on the other side of the substrate SB facing away from the light source 110 so that the first surface S1 faces away from the light source 110.

[0016] As shown in Figure 1, a light source 110 emits light L having an emission field EF, represented by the dashed line between the light source 110 and the first surface S1. The emission field EF represents the initial propagation field of the light L emitted by the light source 110. The dashed line of the emission field EF also illustrates the outermost rays of the initial light L emitted by the light source 110. After the light L passes through the first surface S1 and is deflected by the first surface S1, the propagation direction of the light L changes, and the light L is deflected into a deflected light L0. After the deflected light L0 passes through the second surface S2, the propagation field or light profile of the deflected light L0 changes to the projection field PF, which represents the final projection field of the optical module 100 or the projection device in which it is used. The outermost rays of the deflected light L0, indicated by the dashed line of the projection field PF, have their propagation directions changed to have a larger exit angle relative to the normal direction of the substrate SB, resulting in a larger projection field PF. In other words, the first surface S1 changes the path and / or direction of the light L emitted by the light source 110, and after the deflected light L0 passes through the second surface S2, a larger final field of view generated by the optical module 100 can be obtained, which produces a larger predetermined pattern PA.

[0017] Through the above structural design, the predetermined pattern PA projected by the optical module 100 can have a larger projection field of view because the first surface S1 provides a deflection function and can deflect the light L emitted by the light source 110, and the second surface S2 provides a larger propagation range or light shape for the deflected light L0. Furthermore, the second surface S2, which is configured to project the predetermined pattern PA but does not require light deflection, can be smaller in size, simplifying the design of the second surface S2.

[0018] Please refer to Figure 2, which is a schematic diagram of an optical module according to a variation of the first embodiment of the present invention. As shown in Figure 2, the optical module 100 may further include a shading element 130 surrounding the light source 110 and the optical structure 120. The optical module 100 and the shading element 130 may be used together in a projection device PRO. The shading element 130 has an opening 132, through which the light L deflected by the first surface S1 can pass. In other words, the deflected light L0 (or most of the deflected light L0) is not blocked by the shading element 130 and can pass through the opening 132 to form the predetermined pattern PA. Furthermore, the shading element 130 blocks stray light. Specifically, the deflection of the light L reduces the amount of light traveling in the direction Z (i.e., zero-order light). Furthermore, the stray light LS that is not deflected and travels in the direction Z can be blocked by the shading element 130, thereby reducing eye safety issues caused by zero-order light. According to the embodiment shown in FIG. 2 , the direction Z may be parallel to the initial traveling direction of the light L emitted by the light source 110 , and the direction Z may be, for example, perpendicular to the upper surface or lower surface of the substrate SB, but is not limited thereto.

[0019] Please refer to Figure 3, which is a schematic diagram of an optical module according to a second embodiment of the present invention. The optical module 100 of the second embodiment shown in Figure 3 differs from the first embodiment in that an optical structure 120 may include a first substrate SB1 and a second substrate SB2. The second substrate SB2 corresponds to the first substrate SB1, with a first surface S1 located on one side of the first substrate SB1 and a second surface S2 located on one side of the second substrate SB2. In some embodiments, the optical structure 120 may further include a connecting element CE, and the first substrate SB1 is connected to the second substrate SB2 via the connecting element CE. The connecting element CE may be, for example (but not limited to), a bonding pad, glue, or other suitable element capable of connecting the first and second substrates SB1 and SB2.

[0020] According to the embodiment shown in FIG3 , the first optical layer OL1 can be disposed on the side of the first substrate SB1 facing the light source 110, and the second optical layer OL2 can be disposed on the side of the second substrate SB2 facing the light source 110, such that the first surface S1 faces the light source 110 and the second surface S2 faces the light source 110. However, the structural design of the optical structure 120 is not limited to the above. In the optical structure 120 of the optical module 100 of the present invention, the first optical layer OL1 can be disposed on the side of the first substrate SB1 facing or facing away from the light source 110, and the second optical layer OL2 can be disposed on the side of the second substrate SB2 facing or facing away from the light source 110.

[0021] As shown in FIG3 , a light source 110 may emit light L. This light L enters a first surface S1 and is deflected by the first optical layer OL1 of the first surface S1 into a first deflected light L1 and a second deflected light L2. The direction of travel of the first deflected light L1 is different from the direction of travel of the second deflected light L2. For example, the light L may travel to different portions of the first surface S1 and be deflected by different portions of the first surface S1 into the first deflected light L1 and the second deflected light L2, respectively. The first deflected light L1 passes through a first portion P1 of the second surface S2 formed by the second optical layer OL2 to form a first sub-pattern PA1, and the second deflected light L2 passes through a second portion P2 of the second surface S2 formed by the second optical layer OL2 to form a second sub-pattern PA2. The first sub-pattern PA1 and the second sub-pattern PA2 combine to form a predetermined pattern PA. The first portion P1 is different from the second portion P2; that is, the first portion P1 may at least partially not overlap with the second portion P2. In the embodiment shown in FIG3 , the first portion P1 partially overlaps with the second portion P2. In a variation, the first portion P1 may not overlap the second portion P2 at all.

[0022] The aforementioned structural design of the optical module 100 enables a large projection field of view and can form and project a large predetermined pattern PA by combining two or more simultaneously projected small sub-patterns. In some embodiments, multiple sub-patterns (e.g., the first sub-pattern PA1 and the second sub-pattern PA2) can be projected using a time-multiplexing method rather than simultaneously, but this is not a limitation.

[0023] Please refer to Figures 4 and 5. Figure 4 is a schematic diagram of a projection device comprising two optical modules according to another embodiment of the present invention. Figure 5 is a schematic diagram of a design pattern projected by the projection device shown in Figure 4. As shown in Figures 4 and 5, multiple optical modules 100 according to various embodiments of the present invention can be arranged adjacent to each other to form a projection device PRO. For example, the projection device PRO can include two optical modules 100 arranged adjacent to each other, and the predetermined patterns PA projected by the two optical modules 100 are combined to form a design pattern DPA. According to the embodiments shown in Figures 4 and 5, the optical structure 120 of each of the two optical modules 100 can include a first substrate SB1 and a second substrate SB2 corresponding to the first substrate SB1. The first optical layer OL1 can be disposed on the side of the first substrate SB1 facing away from the light source 110, and the second optical layer OL2 can be disposed on the side of the second substrate SB2 facing the light source 110, such that the first surface S1 faces away from the light source 110 and the second surface S2 faces the light source 110. In other words, both the first optical layer OL1 and the second optical layer OL2 can be disposed between the first substrate SB1 and the second substrate SB2, such that both the first surface S1 and the second surface S2 are located between the first substrate SB1 and the second substrate SB2. However, the structural design of the optical structure 120 in the two optical modules 100 is not limited to the above. In the optical structure 120 of each optical module 100 of the projection device PRO of the present invention, the first optical layer OL1 can be disposed on the side of the first substrate SB1 facing or facing away from the light source 110, and the second optical layer OL2 can be disposed on the side of the second substrate SB2 facing or facing away from the light source 110.

[0024] As shown in Figures 4 and 5 , the light source 110 of one of the two optical modules 100 can emit light La. This light La travels to the first surface S1 and is deflected by the first optical layer OL1 of the first surface S1 into deflected light L0a. The deflected light L0a passes through the second optical layer OL2 of the second surface S2 to produce a predetermined pattern PA. Meanwhile, the light source 110 of the other of the two optical modules 100 can emit light Lb. This light Lb travels to the first surface S1 and is deflected by the first optical layer OL1 of the first surface S1 into deflected light L0b. The deflected light L0b passes through the second optical layer OL2 of the second surface S2 to produce another predetermined pattern PA. The combination of these two predetermined patterns PA forms a design pattern DPA. Accordingly, the projection device PRO including the two optical modules 100 can project the design pattern DPA.

[0025] The direction of travel of the deflected light L0a is different from the direction of travel of the deflected light L0b. For example, as shown in FIG5 , the direction of travel of the deflected light L0a is clockwise at an angle θa relative to the direction Z, while the direction of travel of the deflected light L0b is counterclockwise at an angle θb relative to the direction Z. The angle θa may be the same as or different from the angle θb. The different directions of travel of the deflected light L0a and the deflected light L0b can be achieved, for example, by the different tilt directions of the two first surfaces S1, but are not limited thereto. For example, as shown in FIG4 , the tilt direction of the first surface S1 in the right optical module 100 is different from the tilt direction of the first surface S1 in the left optical module 100.

[0026] The aforementioned structural design of the projection device PRO enables a large projection field of view. Furthermore, the projection device PRO can form and project a large design pattern DPA by combining two or more small predetermined patterns PA simultaneously projected by different optical modules. In some embodiments, multiple predetermined patterns PA can be generated using time-division multiplexing rather than simultaneously, but this is not a limitation.

[0027] In summary, according to the optical module and the projection device used in the embodiments of the present invention, the structural design of the optical module, which includes a first surface configured to deflect light and a second surface configured to project a predetermined pattern, allows for a large projection field of view and reduces eye safety issues. Furthermore, by using the different directions of travel of the deflected light, a large pattern can be formed and projected by combining two or more small patterns. In short, the optical module includes two optical layers to form two different surfaces with different functions. One of the optical layers on the two surfaces provides a deflection function, while the other optical layer on the two surfaces provides a function for generating a predetermined projection pattern. Based on the above structural design, a small-sized optical module capable of projecting patterns with a large field of view is provided. Furthermore, the two different optical layers with simple functions require a simple manufacturing process, thereby reducing manufacturing costs. The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

[0028] 100: Optical module 110: Light Source 120: Optical structure 122: Microstructure 130: shading element 132: Opening CE: Connecting Element DPA: Design Pattern EF: Launch range L, La, Lb: light L0, L0a, L0b: deflected light L1: first deflected light L2: Second deflected light LS: Stray Light OL1: first optical layer OL2: Second optical layer P1: Part 1 P2: Part 2 PA: Predetermined pattern PA1: first sub-pattern PA2: Second sub-pattern PF: Projection Range PRO: Projection device S1: First surface S2: Second surface SB:Substrate SB1: First substrate SB2: Second substrate Z: Direction θa,θb: Angle

Claims

1. An optical module, comprising: A light source, used to emit a ray of light; An optical structure is disposed on the light source and used to receive the light. The optical structure includes: a first substrate; a second substrate corresponding to the first substrate; a connecting element, wherein the first substrate is connected to the second substrate through the connecting element; a first optical layer having a first surface configured to deflect the light, wherein the first optical layer is disposed on one side of the first substrate and the first surface faces away from the light source; and a second optical layer having a second surface configured to project a predetermined pattern when the light passes through the second surface, the second surface having a plurality of microstructures, wherein the second optical layer is disposed on one side of the second substrate, the second surface corresponds to the first surface and faces the light source, and the first surface is disposed between the second surface and the light source; wherein the light is deflected by the first surface into a first deflected light and a second deflected light, and the direction of travel of the first deflected light is different from the direction of travel of the second deflected light. The first optical layer and the second optical layer are both located between the first substrate and the second substrate, and the first substrate, the second substrate and the connecting element surround the first optical layer and the second optical layer, wherein there is a gap between the first surface of the first optical layer and the second surface of the second optical layer.

2. The optical module as claimed in claim 1, wherein the light source includes one of a laser diode, a vertical cavity surface-emitting laser, a light-emitting diode, and a photonic crystal surface-emitting laser.

3. The optical module as claimed in claim 1, wherein the first surface includes a bevel, a blazed grating, a prism, or an array of prisms.

4. The optical module as claimed in claim 1, wherein the second surface includes a microlens array, a diffractive optical element, or a meta-interface.

5. The optical module of claim 1, wherein the first deflected light passes through a first portion of the second surface to form a first sub-pattern, and the second deflected light passes through a second portion of the second surface to form a second sub-pattern, wherein the first sub-pattern and the second sub-pattern are combined to form the predetermined pattern.

6. The optical module as claimed in claim 5, wherein the first portion does not at least partially overlap with the second portion.

7. The optical module of claim 1 further includes a light-shielding element surrounding the light source and the optical structure, wherein the light-shielding element has an opening through which light rays deflected by the first surface can pass.

8. A projection device, comprising: At least two optical modules as described in claim 1, wherein the at least two optical modules are arranged adjacent to each other, and the predetermined patterns projected by the at least two optical modules combine to form a design pattern.

9. An optical module, comprising: A light source, used to emit a ray of light; An optical structure is disposed on the light source and used to receive the light. The optical structure includes: a first substrate; a second substrate corresponding to the first substrate; a connecting element, wherein the first substrate is connected to the second substrate through the connecting element; a first optical layer having a first surface configured to deflect the light, wherein the first optical layer is disposed on one side of the first substrate and the first surface faces the light source; and a second optical layer having a second surface configured to project a predetermined pattern when the light passes through the second surface, the second surface having a plurality of microstructures, wherein the second optical layer is disposed on one side of the second substrate, the second surface corresponds to the first surface and faces away from the light source, and the second surface is disposed between the first surface and the light source; wherein the light is deflected by the first surface into a first deflected light and a second deflected light, and the direction of travel of the first deflected light is different from the direction of travel of the second deflected light. The first optical layer and the second optical layer are both located between the first substrate and the second substrate, and the first substrate, the second substrate and the connecting element surround the first optical layer and the second optical layer, wherein there is a gap between the first surface of the first optical layer and the second surface of the second optical layer.

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