TW202235902A - Optical sensing system - Google Patents

Abstract

An optical sensing system including a light source, a projection module and a sensing module is provided. The light source is adapted to provide an illumination beam. The projection module is disposed on the transmission path of the illumination beam. The illumination beam is transmitted to a target object by the projection module. The target object reflects the illumination beam to form a sensing beam. The sensing module is disposed on the transmission path of the sensing beam. The sensing module includes at least one sensing unit. Each sensing unit includes a light receiving element and a sensing element, and the sensing unit has an optical axis. The light receiving element is located between the target object and the sensing element, and is adapted to guide the sensing beam to the sensing element along the optical axis. Wherein the light receiving element has a focus on the optical axis, and the sensing element is not located on the focus.

Description

Optical Sensing System

The present invention relates to an electronic device, and more particularly to an optical sensing system.

LiDAR (Light (Laser) Detection and Ranging, LiDAR) is an optical remote sensing technology that uses light to measure the distance of an object. LiDAR can measure the distance with high precision, identify the appearance of objects and establish a three-dimensional geographic information model of the surrounding area. It has the advantages of high measurement distance, high precision, and high recognition. Sensing information such as the shape and distance of surrounding obstacles. The scanning range of lidar is 100 to 200 meters, so it can meet the needs of self-driving cars for farther and more accurate sensing.

In optical sensing, if more signal light energy can be received, the measurement distance will be farther, the signal-to-noise ratio will be improved, and the ability to resist stray light (such as sunlight or ambient light) will be better. It is less likely to be misjudged. It can be known from the empirical formula that the light sensor can receive signal light energy that the light sensor can receive signal light energy is proportional to the light receiving area. And when there is no light-receiving element, the light-receiving area is equal to the area of the light sensor, and the light-receiving efficiency is 1. If there is a light-receiving element, the light-receiving area is equal to the area of the light-receiving element, and the light-receiving efficiency needs to be calculated. However, this method will cause some light to be totally reflected in the light-receiving element and unable to emit light when it is incident at a large angle (above 50°), which will cause loss, so that part of the light will be deflected and cannot be received by the photosensor . So not only no gain, but more loss.

The "Prior Art" paragraph is only used to help understand the content of the present invention, so the content disclosed in the "Prior Art" paragraph may contain some conventional technologies that do not constitute the knowledge of those with ordinary skill in the art. The content disclosed in the "Prior Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by those with ordinary knowledge in the technical field before the application of the present invention.

The invention provides an optical sensing system, which can increase the receiving amount of light signals, so as to improve the optical sensing effect.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one or part or all of the above objectives or other objectives, the present invention provides an optical sensing system, including a light source, a projection module and a sensing module. The light source is used for providing illumination light beams. The projection module is arranged on the transmission path of the illumination beam. The light beam is delivered to the target object through the projection module. The target object reflects the illumination beam to generate the sensing beam. The sensing module is arranged on the transmission path of the sensing light beam. The sensing module includes at least one sensing unit. Each sensing unit includes a light receiving element and a sensing element, and the sensing unit has an optical axis. The light receiving element is located between the target object and the sensing element, and is used to guide the sensing light beam to the sensing element along the optical axis, wherein the light receiving element has a focus on the optical axis, and the sensing element is not located on the focus.

According to an embodiment, in the above optical scanning system, the number of the at least one sensing unit is multiple.

According to an embodiment, in the above optical scanning system, the directions of the plurality of optical axes of the plurality of sensing units are different from each other.

According to an embodiment, in the above optical scanning system, the angles between the plurality of optical axes of the adjacent sensing units are the same.

According to an embodiment, in the above-mentioned optical scanning system, at least two of the plurality of sensing surfaces of the plurality of sensing elements respectively have an included angle greater than 90 degrees with the central axis of the sensing module, so The optical axis is perpendicular to the sensing surface.

According to an embodiment, in the above-mentioned optical scanning system, at least two of the plurality of sensing surfaces of the plurality of sensing elements have an included angle less than 90 degrees with the central axis of the sensing module, and the light The axis is perpendicular to the sensing face.

According to an embodiment, in the above optical scanning system, the sensing element is located between the light receiving element and the focal point.

According to an embodiment, in the above optical scanning system, the focal point is located between the light receiving element and the sensing element.

According to an embodiment, in the above-mentioned optical scanning system, the at least one sensing unit further includes a light-shielding element disposed around the light-receiving element, and the light-receiving element is located between the light-shielding element and the sensing element. between.

According to an embodiment, in the above optical scanning system, the at least one sensing unit further includes a reflector disposed between the light receiving element and the sensing element.

According to an embodiment, in the above optical scanning system, the light receiving area of the light receiving element is larger than the area of the sensing surface of the sensing element.

According to an embodiment, in the above optical scanning system, the light receiving element includes a lens.

Based on the above, in the optical sensing system of the present invention, the sensing module includes a light source, a projection module, and a sensing module, wherein the sensing module is arranged on the transmission path of the sensing light beam, and the sensing module includes at least one sensing unit. Each sensing unit includes a light receiving element and a sensing element. Wherein, the light receiving element has a focus on the optical axis, and the sensing element is not located at the focus of the light receiving element. In this way, the sensing light beam transmitted to the edge of the light receiving element can be prevented from being transmitted out of the sensing element, thereby causing loss of light signal. Therefore, the design of the present invention can increase the receiving amount of the optical signal, so as to improve the optical sensing effect.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only directions referring to the attached drawings. Accordingly, the directional terms are used to illustrate and not to limit the invention.

FIG. 1 is a schematic diagram of an optical sensing system according to an embodiment of the present invention. Please refer to Figure 1. The present embodiment provides an optical sensing system 100 for sensing a target object 10 , such as any object with a solid shape. The optical sensing system 100 includes a light source 110 , a projection module 120 and a sensing module 130 . The light source 110 is used for providing an illumination beam L1. The projection module 120 is disposed on the transmission path of the illumination beam L1. In this embodiment, the light source 110 , the projection module 120 and the sensing module 130 in the optical sensing system 100 are arranged in a non-coaxial manner. The illumination beam L1 is delivered to the target object 10 through the projection module 120 . The target object 10 reflects the illumination beam L1 to generate the sensing beam L2. In this embodiment, the light source 110 is, for example, a semiconductor laser using infrared light, but the invention is not limited thereto.

In this embodiment, the projection module 120 is, for example, any number of optical elements (such as lenses), a flat-field laser focusing lens (F-theta lens) or a combination of mirrors and microelectromechanical systems (Microelectromechanical Systems, MEMS), but The present invention is not limited thereto. That is to say, in this embodiment, the illumination light beam L1 provided by the light source 110 can be projected in a scanning manner through the MEMS in the projection module 120 and the flat-field laser focusing lens.

In this embodiment, the optical sensing system 100 further includes a processor 140, electrically connected to the light source 110 and the sensing module 130, for controlling the light source 110, reading data from the sensing module 130 and/or further Control based on the above data. The processor 140 is, for example, a central processing unit (Central Processing Unit, CPU), or other programmable general purpose or special purpose microprocessor (Microprocessor), digital signal processor (Digital Signal Processor, DSP), programmable controller, application specific integrated circuit (Application Specific Integrated Circuit, ASIC) or other similar components or a combination of the above components, the present invention is not limited thereto. For example, in this embodiment, the processor 140 can turn on/off the light source 110 instantly or at any time according to the light signal received by the sensing module 130, or adjust the power of the light source 110. The present invention does not limited to this.

FIG. 2 is a schematic diagram of the sensing module in FIG. 1 . Please refer to Figure 1 and Figure 2 at the same time. The sensing module 130 is disposed on the transmission path of the sensing light beam L2 for receiving the sensing light beam L2 for signal identification. The sensing module 130 includes at least one sensing unit U. In this embodiment, the number of sensing units U is, for example, one group. In other words, the sensing module 130 of this embodiment is composed of a single sensing unit U. But in other embodiments, the number of sensing units U may be plural. Each group of sensing units U includes a light receiving element 132 and a sensing element 134 , and the sensing unit U has an optical axis I. The light receiving element 132 is used to guide the sensing light beam L2 to the sensing element 134 along the optical axis I, and is used to increase the light receiving area. In this embodiment, the light receiving element 132 includes a lens, such as a lens with positive diopter, but the present invention is not limited thereto. Therefore, the light receiving element 132 has a focal point F on the optical axis I.

The sensing element 134 of the sensing unit U is located on the transmission path of the sensing light beam L2 , and the light receiving element 132 is located between the target object 10 and the sensing element 134 . The sensing element 134 is, for example, a photodiode (Photodiode, PD) or an collapsed photodiode (Avalanche photodiode, APD), and the invention is not limited thereto. In this embodiment, the light receiving area of the light receiving element 132 is larger than the area of the sensing surface of the sensing element 134 , as shown in FIG. 2 . It is worth noting that the sensing element 134 is not located at the focal point F of the light receiving element 132 . For example, in this embodiment, the sensing element 134 is located between the light receiving element 132 and its focal point F. As shown in FIG. Therefore, when the sensing light beam L2 passes through the light receiving element 132 , the sensing light beam L2 is refracted and condensed by passing through the light receiving element 132 , and can continue to be passed to the sensing element 134 . In this way, the sensing light beam L2 delivered to the edge of the light-receiving element 132 (that is, the light that cannot be focused on the focal point F after passing through the light-receiving element 132 ) can be prevented from being transmitted to the outside of the sensing element 134, resulting in a light signal loss. In other words, the design of this embodiment can increase the amount of received light signals, so as to improve the optical sensing effect.

FIG. 3 is a schematic diagram of a sensing module according to an embodiment of the invention. Please refer to Figure 3. The sensing module 130A of this embodiment is similar to the sensing module 130 shown in FIG. 2 . The difference between the two is that in this embodiment, there are multiple sensing units U, and the directions of the optical axes I of the sensing units U are different from each other. Specifically, the number of sensing units U in this embodiment is two. The sensing surface S of the sensing element 134 in the two sensing units U and the central axis C of the sensing module 130A respectively have an included angle B greater than 90 degrees, and the respective optical axes I of the two sensing units U perpendicular to the corresponding sensing surface S. In other words, the sensing surface S of the sensing element 134 in this embodiment faces away from and is inclined to the central axis C. As shown in FIG. Therefore, when the light receiving angle of a single sensing unit U is 60 degrees, the light receiving angle of the sensing module 130A of this embodiment can reach 120 degrees. That is, the two sensing units U respectively receive the incident light from minus 60 degrees to 0 degrees and the incident light from 0 degrees to plus 60 degrees, as shown in FIG. 3 . In this embodiment, the comprehensive optical efficiency of the sensing light beam L2 with an incident angle of plus or minus 50 degrees (which can be defined by the ratio of the product of the light-receiving area and the light-receiving efficiency to the sensing area) is up to 128%.

FIG. 4 is a schematic diagram of a sensing module according to another embodiment of the present invention. Please refer to Figure 4. The sensing module 130B of this embodiment is similar to the sensing module 130 shown in FIG. 2 . The difference between the two is that, in this embodiment, the number of sensing units U is increased to three, the optical axis I of each of the three sensing units U is perpendicular to the corresponding sensing surface S, and the adjacent sensing units The optical axes I of U subtend the same angle with each other. Therefore, when the light receiving angle of a single sensing unit U is 60 degrees, the light receiving angle of the sensing module 130B of this embodiment can reach 180 degrees. That is, the three sensing units U respectively receive incident light from minus 90 degrees to minus 30 degrees, from minus 30 degrees to plus 30 degrees, and from plus 30 degrees to plus 90 degrees, as shown in FIG. 4 .

FIG. 5 is a schematic diagram of a sensing module according to another embodiment of the present invention. Please refer to Figure 5. The sensing module 130C of this embodiment is similar to the sensing module 130A shown in FIG. 3 . The difference between them is that, in this embodiment, the sensing surfaces S of the sensing elements 134 in the two sensing units U and the central axis C of the sensing module 130C respectively have an included angle B smaller than 90 degrees. In other words, the sensing surface S of the sensing element 134 in this embodiment faces and is inclined to the central axis C. As shown in FIG. Therefore, when the light receiving angle of a single sensing unit U is 60 degrees, the light receiving angle of the sensing module 130C of this embodiment can reach 120 degrees. Meanwhile, the configuration of this embodiment is applicable to sensing modules 130C with different volumes.

FIG. 6 is a schematic diagram of a sensing module according to another embodiment of the present invention. Please refer to Figure 6. The sensing module 130D of this embodiment is similar to the sensing module 130 shown in FIG. 2 . The difference between the two is that, in this embodiment, the sensing unit U1 further includes a light-shielding element 136, which is arranged around the light-receiving element 132, and the light-receiving element 132 is located between the light-shielding element 136 and the sensing element 134, that is, light-shielding The element 136 can be disposed on the light incident side of the light receiving element 132 . In detail, the light-shielding element 136 is disposed at the junction where the light-receiving element 132 can receive the maximum incident angle, so as to block external noise light from entering the light-receiving element 132 . In this way, good sensing effect can be improved. In this embodiment, the light-shielding element 136 is disposed on both the light-incident side and the light-emitting side of the light-receiving element 132, but in other embodiments, the light-shielding element 136 may only be disposed on the light-incident side of the light-receiving element 132, and the present invention does not Not limited to this.

FIG. 7 is a schematic diagram of a sensing module according to another embodiment of the present invention. Please refer to Figure 7. The sensing module 130E of this embodiment is similar to the sensing module 130D shown in FIG. 6 . The difference between the two is that, in this embodiment, the light-shielding element 136 is only disposed on the light-incident side of the light-receiving element 132 , and the sensing unit U2 also includes a reflector 138 disposed between the light-receiving element 132 and the sensing element 134 between. In detail, the reflector 138 is, for example, a ring-shaped reflective cylinder or a reflective ring with a reflective material on the inner wall, as shown in FIG. 7 . In detail, the reflector 138 is disposed around the light transmission path between the light emitting side of the light receiving element 132 and the sensing element 134 to reflect the sensing light beam L2 transmitted inside until the sensing light beam L2 is transmitted to the sensing element 134 . In this way, the sensing intensity can be improved. In addition, the focal point F of the light receiving element 132 is located between the light receiving element 132 and the sensing element 134 . That is, the sensing element 134 is disposed behind the focal point F of the light receiving element 132 , so that the sensing light beam L2 passing through the light receiving element 132 and entering the reflector 138 achieves a uniform incident effect by defocusing. In this way, good sensing effect can be improved.

To sum up, in the optical sensing system of the present invention, the sensing module includes a light source, a projection module, and a sensing module, wherein the sensing module is arranged on the transmission path of the sensing light beam, and the sensing module The group includes at least one sensing unit. Each sensing unit includes a light receiving element and a sensing element. Wherein, the light receiving element has a focus on the optical axis, and the sensing element is not located at the focus of the light receiving element. In this way, the sensing light beam transmitted to the edge of the light receiving element can be prevented from being transmitted out of the sensing element, thereby causing loss of light signal. Therefore, the design of the present invention can increase the receiving amount of the optical signal, so as to improve the optical sensing effect.

But what is described above is only a preferred embodiment of the present invention, and should not limit the scope of implementation of the present invention with this, that is, all simple equivalent changes and modifications made according to the patent scope of the present invention and the content of the description of the invention, All still belong to the scope covered by the patent of the present invention. In addition, any embodiment or scope of claims of the present invention does not need to achieve all the objectives or advantages or features disclosed in the present invention. In addition, the abstract and the title are only used to assist the search of patent documents, and are not used to limit the scope of rights of the present invention. In addition, terms such as "first" and "second" mentioned in this specification or the scope of the patent application are only used to name elements (elements) or to distinguish different embodiments or ranges, and are not used to limit the number of elements. upper or lower limit.

10: target object 100: Optical sensing system 110: light source 120:Projection module 130, 130A, 130B, 130C, 130D, 130E: sensing module 132: light receiving element 134: sensing element 136: shading piece 138: reflector 140: Processor B: Angle C: central axis F: focus L1: Lighting beam L2: Sensing beam I: optical axis S: Sensing surface U, U1, U2: sensing unit

FIG. 1 is a schematic diagram of an optical sensing system according to an embodiment of the present invention. FIG. 2 is a schematic diagram of the sensing module in FIG. 1 . FIG. 3 is a schematic diagram of a sensing module according to an embodiment of the invention. FIG. 4 is a schematic diagram of a sensing module according to another embodiment of the present invention. FIG. 5 is a schematic diagram of a sensing module according to another embodiment of the present invention. FIG. 6 is a schematic diagram of a sensing module according to another embodiment of the present invention. FIG. 7 is a schematic diagram of a sensing module according to another embodiment of the present invention.

10: target object

100: Optical sensing system

110: light source

120:Projection module

130:Sensing module

132: light receiving element

134: sensing element

140: Processor

L1: Lighting beam

L2: Sensing beam

U: sensing unit

Claims (12)

An optical sensing system for sensing a target object, including: a light source, a projection module and a sensing module; wherein, The light source is used to provide an illumination beam; The projection module is arranged on the transmission path of the illumination beam, the illumination beam is transmitted to the target object by the projection module, and the target object reflects the illumination beam to generate a sensing beam; and The sensing module is arranged on the transmission path of the sensing light beam, the sensing module includes at least one sensing unit, each of the at least one sensing unit includes a light receiving element and a sensing element, and each The at least one sensing unit has an optical axis, the light receiving element is located between the target object and the sensing element, and is used to guide the sensing light beam to the optical axis along the optical axis. A sensing element, wherein the light receiving element has a focal point on the optical axis, and the sensing element is not located at the focal point. The optical sensing system as claimed in claim 1, wherein the number of the at least one sensing unit is multiple. The optical sensing system as claimed in claim 2, wherein the directions of the plurality of optical axes of the plurality of sensing units are different from each other. The optical sensing system according to claim 2, wherein the angles between the optical axes of the adjacent sensing units are the same. The optical sensing system according to claim 2, wherein at least two of the plurality of sensing surfaces of the plurality of sensing elements respectively have an included angle greater than 90 degrees with the central axis of the sensing module, The optical axis is perpendicular to the sensing surface. The optical sensing system according to claim 2, wherein at least two of the plurality of sensing surfaces of the plurality of sensing elements have angles less than 90 degrees with the central axis of the sensing module, and the The optical axis is perpendicular to the sensing surface. The optical sensing system as claimed in claim 1, wherein the sensing element is located between the light receiving element and the focal point. The optical sensing system as claimed in claim 1, wherein the focal point is located between the light receiving element and the sensing element. In the optical sensing system according to claim 1, the at least one sensing unit further includes a light-shielding element disposed around the light-receiving element, and the light-receiving element is located between the light-shielding element and the sensing element between. In the optical sensing system according to claim 1, the at least one sensing unit further includes a reflector disposed between the light receiving element and the sensing element. In the optical sensing system according to claim 1, the light receiving area of the light receiving element is larger than the area of the sensing surface of the sensing element. In the optical sensing system according to claim 1, the light receiving element includes a lens.

Images