阅读说明：本技术 菲涅尔透镜及探测器 (Fresnel lens and detector ) 是由 周良 姜君城 何孟彪 于 2021-08-30 设计创作，主要内容包括：本申请提供一种菲涅尔透镜及探测器,菲涅尔透镜包括透镜本体,透镜本体具有沿第一方向相背设置的入射面和出射面；透镜本体的入射面或出射面具有多个阵列分布的菲涅尔透镜单元；多个菲涅尔透镜单元的结构各不相同；菲涅尔透镜单元包括多个连续设置的菲涅尔齿,菲涅尔齿具有齿峰以及分别位于齿峰两侧的第一齿谷和第二齿谷,齿峰和第一齿谷之间连接有主菲涅尔面,齿峰和第二齿谷之间连接有辅菲涅尔面；主菲涅尔面的面型为自由曲面。探测器包括传感元件和菲涅尔透镜。通过采用上述技术方案,提高了菲涅尔透镜的聚焦效果,则该菲涅尔透镜能够满足要求更高、探测区间范围更大的聚焦要求,从而有助于提高传感元件的识别灵敏度。(The application provides a Fresnel lens and a detector, wherein the Fresnel lens comprises a lens body, and the lens body is provided with an incident surface and an emergent surface which are arranged along a first direction in a back-to-back manner; the incident surface or the emergent surface of the lens body is provided with a plurality of Fresnel lens units distributed in an array; the structures of the Fresnel lens units are different; the Fresnel lens unit comprises a plurality of Fresnel teeth which are continuously arranged, each Fresnel tooth is provided with a tooth peak, a first tooth valley and a second tooth valley which are respectively positioned at two sides of the tooth peak, a main Fresnel surface is connected between the tooth peak and the first tooth valley, and an auxiliary Fresnel surface is connected between the tooth peak and the second tooth valley; the surface type of the primary Fresnel surface is a free-form surface. The detector comprises a sensing element and a fresnel lens. By adopting the technical scheme, the focusing effect of the Fresnel lens is improved, and the Fresnel lens can meet the focusing requirements of higher requirements and larger detection interval range, so that the identification sensitivity of the sensing element is improved.)

1. A Fresnel lens is used for focusing incident light on a sensing element; the Fresnel lens comprises a lens body, wherein the lens body is provided with an incident surface and an emergent surface which are arranged along a first direction in an opposite way; the incident surface or the emergent surface of the lens body is provided with a plurality of Fresnel lens units distributed in an array manner; the Fresnel lens unit is characterized in that the structures of the Fresnel lens units are different; the Fresnel lens unit comprises a plurality of Fresnel teeth which are continuously arranged, each Fresnel tooth is provided with a tooth peak, a first tooth valley and a second tooth valley, the first tooth valley and the second tooth valley are respectively positioned on two sides of the tooth peak, a main Fresnel surface is connected between the tooth peak and the first tooth valley, and an auxiliary Fresnel surface is connected between the tooth peak and the second tooth valley; the surface type of the primary Fresnel surface is a free-form surface.

2. A fresnel lens according to claim 1, wherein a projection line of the tooth peaks on a plane perpendicular to the first direction is a closed free curve.

3. A fresnel lens according to claim 2, wherein projected lines of the first and second valleys on a vertical plane in the first direction are both closed free curves.

4. The fresnel lens according to claim 1, wherein the secondary fresnel surface of each of the fresnel teeth is an arc-shaped surface, the secondary fresnel surface being parallel to the first direction.

5. A fresnel lens according to claim 1, wherein, of the exit surface and the entrance surface of the lens body, a surface shape in which the fresnel lens unit is not provided is a flat surface, a cylindrical surface, a spherical surface, an ellipsoidal surface, or a free curved surface.

6. The Fresnel lens according to any one of claims 1 to 5, wherein the Fresnel lens unit is arranged on the exit surface and the entrance surface of the lens body, and the Fresnel lens unit is sequentially divided into a first dimming region, a second dimming region and a third dimming region along a second direction, and the first dimming region, the second dimming region and the third dimming region are respectively provided with a plurality of Fresnel lens units; the Fresnel lens units in the first light adjusting area, the second light adjusting area and the third light adjusting area are respectively used for focusing incident light rays from different detection intervals in the second direction on the sensing element;

in any one of the first dimming area, the second dimming area and the third dimming area, the fresnel lens units are sequentially arranged along a third direction and are respectively used for focusing incident light rays from different detection sections in the third direction on the sensing element; wherein the first direction, the second direction and the third direction are mutually perpendicular in pairs.

7. The fresnel lens according to claim 6, wherein the number of the fresnel lens units in the first dimming area is greater than or equal to the number of the fresnel lens units in the second dimming area, and the number of the fresnel lens units in the second dimming area is greater than the number of the fresnel lens units in the third dimming area.

8. The fresnel lens according to claim 6, wherein the first dimming region has 7 fresnel lens units arranged in sequence in the third direction, the second dimming region has 7 fresnel lens units arranged in sequence in the third direction, and the third dimming region has 5 fresnel lens units arranged in sequence in the third direction.

9. The fresnel lens according to claim 6, wherein the fresnel lens unit located in the middle of the first dimming region is an intermediate fresnel lens unit including an intermediate convex surface portion having an optical axis perpendicular to a middle surface of the intermediate convex surface portion and a plurality of the fresnel teeth arranged sequentially outward around the intermediate convex surface portion; the fresnel lens units other than the intermediate fresnel lens unit each have a central axis parallel to the optical axis, and the optical axis is closest to a focal point of the fresnel lens among the optical axis and the central axes.

10. A probe comprising a sensor element, further comprising a fresnel lens according to any one of claims 1 to 9, wherein the light-sensitive surface of the sensor element is disposed at the focus of the fresnel lens.

Technical Field

The application belongs to the technical field of optics, and more specifically relates to a Fresnel lens and a detector.

Background

The detector usually adopts a mode that a sensing element is matched with a Fresnel lens to identify the human body movement condition in a detection interval, wherein the Fresnel lens is used for focusing infrared light generated when a human body moves in the detection interval into the sensing element so that the sensing element generates a corresponding electric signal; for example, the sensing element may signal an alarm, turn on a light, or open a door.

The fresnel lens generally includes a plurality of fresnel lens units that are arranged in an array, and the fresnel teeth of each fresnel lens unit are all circular rings, so that the focuses of each fresnel lens unit are different, and thus, the fresnel lens has a phenomenon that infrared light cannot be completely focused on the sensing element, that is, the focusing effect of the fresnel lens is poor, and the recognition sensitivity of the sensing element is affected.

Disclosure of Invention

One of the purposes of the embodiment of the application is as follows: the utility model provides a Fresnel lens, aims at solving among the prior art, Fresnel lens's focusing effect is poor leads to the technical problem that sensing element's discernment sensitivity is low.

In order to solve the technical problem, the embodiment of the application adopts the following technical scheme:

a Fresnel lens is provided for focusing incident light onto a sensing element; the Fresnel lens comprises a lens body, wherein the lens body is provided with an incident surface and an emergent surface which are arranged along a first direction in an opposite way; the incident surface or the emergent surface of the lens body is provided with a plurality of Fresnel lens units distributed in an array manner; the structures of the Fresnel lens units are different; the Fresnel lens unit comprises a plurality of Fresnel teeth which are continuously arranged, each Fresnel tooth is provided with a tooth peak, a first tooth valley and a second tooth valley, the first tooth valley and the second tooth valley are respectively positioned on two sides of the tooth peak, a main Fresnel surface is connected between the tooth peak and the first tooth valley, and an auxiliary Fresnel surface is connected between the tooth peak and the second tooth valley; the surface type of the primary Fresnel surface is a free-form surface.

In one embodiment, a projection line of the tooth peak on a vertical plane of the first direction is a closed free curve.

In one embodiment, projection lines of the first tooth valley and the second tooth valley on a vertical plane of the first direction are both closed free curves.

In one embodiment, the secondary fresnel surface of each of the fresnel teeth is an arc-shaped surface, and the secondary fresnel surface is parallel to the first direction.

In one embodiment, of the exit surface and the entrance surface of the lens body, the surface shape of the lens body on which the fresnel lens unit is not disposed is a plane, a cylindrical surface, a spherical surface, an ellipsoidal surface, or a free-form surface.

In one embodiment, one of the exit surface and the entrance surface of the lens body, in which the fresnel lens unit is disposed, is sequentially divided into a first dimming region, a second dimming region and a third dimming region along a second direction, and the first dimming region, the second dimming region and the third dimming region are all provided with a plurality of fresnel lens units; the Fresnel lens units in the first light adjusting area, the second light adjusting area and the third light adjusting area are respectively used for focusing incident light rays from different detection intervals in the second direction on the sensing element;

in any one of the first dimming area, the second dimming area and the third dimming area, the fresnel lens units are sequentially arranged along a third direction and are respectively used for focusing incident light rays from different detection sections in the third direction on the sensing element; wherein the first direction, the second direction and the third direction are mutually perpendicular in pairs.

In one embodiment, the number of fresnel lens units in the first dimming area is greater than or equal to the number of fresnel lens units in the second dimming area, and the number of fresnel lens units in the second dimming area is greater than the number of fresnel lens units in the third dimming area.

In one embodiment, the first dimming region has 7 fresnel lens units sequentially arranged in the third direction, the second dimming region has 7 fresnel lens units sequentially arranged in the third direction, and the third dimming region has 5 fresnel lens units sequentially arranged in the third direction.

In one embodiment, the fresnel lens unit located in the middle of the first dimming region is an intermediate fresnel lens unit, the intermediate fresnel lens unit includes an intermediate convex surface portion and a plurality of fresnel teeth sequentially arranged outward around the intermediate convex surface portion, and the intermediate convex surface portion has an optical axis perpendicular to a middle surface of the intermediate convex surface portion; the fresnel lens units other than the intermediate fresnel lens unit each have a central axis parallel to the optical axis, and the optical axis is closest to a focal point of the fresnel lens among the optical axis and the central axes.

The embodiment of the application further provides a detector, which comprises a sensing element and the Fresnel lens, wherein the light sensing surface of the sensing element is arranged at the focusing position of the Fresnel lens.

The beneficial effect of the Fresnel lens that this application embodiment provided lies in: compared with the prior art, the Fresnel lens units are different in structure, and the surface type of the main Fresnel surface formed by connecting the first tooth valleys and the tooth peaks of each Fresnel tooth is a free curved surface; like this, when designing fresnel lens, can correspond the face type that sets up the main fresnel surface of every fresnel lens unit according to the focus demand of reality, make every fresnel lens unit's structure all can correspond the adjustment according to its main fresnel surface's face type, thus, fresnel lens's design is more nimble, help making the focus of a plurality of fresnel lens units all the same, make also that a plurality of fresnel lens units can both focus on the sensing element with the incident light line in surveying the interval, fresnel lens's focus effect has been improved, then this fresnel lens can satisfy the requirement higher, survey the focus requirement that the interval scope is bigger, thereby help improving sensing element's discernment sensitivity. Correspondingly, the detector with the Fresnel lens has the advantage of better focusing effect, so that the detection sensitivity and the detection effect of the detector are improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic perspective view of a fresnel lens cooperating with a sensing element according to an embodiment of the present disclosure;

FIG. 2 is a front view of the Fresnel lens provided in FIG. 1;

FIG. 3 is a perspective cross-sectional view of FIG. 2;

FIG. 4 is an enlarged view of a portion of FIG. 3 at A;

FIG. 5 is a vertical view of the Fresnel lens provided in FIG. 1;

fig. 6 is a light path diagram of the fresnel lens provided in fig. 1 in a horizontal direction.

Wherein, in the figures, the respective reference numerals:

10-a fresnel lens; 11-a lens body; 12-a fresnel lens unit; 12 a-an intermediate fresnel lens element; 121-fresnel teeth; 1211-tooth peak; 1212-first valley; 1213-second valley; 1214-a primary fresnel surface; 1215-an auxiliary fresnel surface; 122-a convex portion; 122 a-a medial convex portion; 20-a sensing element; z-a first direction; y-a second direction; x-third direction; a-a first dimming area; b-a second dimming area; c-third dimming area.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

In the description of the present application, it is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings, which is for convenience and simplicity of description, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, is not to be considered as limiting.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise, wherein two or more includes two.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The following detailed description is made with reference to the accompanying drawings and examples:

example one

Referring to fig. 1 to 4, a fresnel lens 10 according to an embodiment of the present disclosure is mainly used for focusing incident light on a sensing element 20; the sensing elements 20 are disposed at intervals on one side of the exit surface of the fresnel lens 10, and the light-sensing surfaces of the sensing elements 20 are disposed at the focusing position of the fresnel lens 10, so that the fresnel lens 10 focuses the incident light into the sensing elements 20. It should be noted that, the sensing element 20 and the fresnel lens 10 are main elements of the detector, in practical application, when a human body moves in a detection interval of the detector, a temperature difference is formed between a temperature of the human body and an ambient temperature, so that the human body generates infrared light, the infrared light is incident to the fresnel lens 10, and the fresnel lens 10 focuses the infrared light on the sensing element 20, so that the sensing element 20 sends out a corresponding electrical signal; wherein, the electric signal can be a control signal for opening a door, turning on a light, alarming and the like; the detector formed by the sensing element 20 and the fresnel lens 10 can also be used to identify other moving objects besides human body.

In a specific embodiment, the fresnel lens 10 includes a lens body 11, the lens body 11 has an incident surface and an exit surface, the incident surface and the exit surface of the lens body 11 are disposed on the lens body 11 in a reverse manner along the first direction Z, that is, two side surfaces of the lens body 11 disposed on the reverse side along the first direction Z are the incident surface and the exit surface, respectively.

Alternatively, as shown in fig. 1, the exit surface of the lens body 11 has a plurality of fresnel lens units 12, and the plurality of fresnel lens units 12 are distributed in an array; alternatively, in another embodiment, the fresnel lens 10 is disposed on the incident surface of the lens body 11, and the fresnel lens units 12 are distributed in an array. It should be noted that a plurality of fresnel lens units 12 are used to focus incident light rays in a plurality of different detection regions onto the sensing element 20, and it is understood that each fresnel lens unit 12 is used to focus incident light rays in its corresponding detection region onto the sensing element 20; wherein, the incident direction of the incident light in the multiple detection regions can be different.

The structure of the fresnel lens units 12 is different, and it should be understood that, in the present embodiment, the structure of the fresnel lens units 12 on the fresnel lens unit 10 is not limited, that is, the specific structure of the fresnel lens unit 12 can be adjusted according to actual situations. Each fresnel lens unit 12 includes a plurality of fresnel teeth 121, and the plurality of fresnel teeth 121 are continuously provided on the exit surface or the entrance surface of the lens body 11. Each fresnel tooth 121 has a peak 1211, a first valley 1212 and a second valley 1213, the first valley 1212 and the second valley 1213 are respectively located on both sides of the peak 1211, a primary fresnel surface 1214 is connected between the peak 1211 and the first valley 1212, and a secondary fresnel surface 1215 is connected between the peak 1211 and the second valley 1213, so that the primary fresnel surface 1214 and the secondary fresnel surface 1215 of each fresnel tooth 121 are adjacently located; the first valley 1212 and the second valley 1213 of each fresnel tooth 121 are respectively connected to two adjacent fresnel teeth 121, and it is understood that the first valley 1212 of each fresnel tooth 121 is connected to the second valley 1213 of one of the adjacent fresnel teeth 121 and is spaced from or overlaps the second valley 1213 of the adjacent fresnel tooth 121, and the second valley 1213 of each fresnel tooth 121 is connected to the first valley 1212 of another adjacent fresnel tooth 121 and is spaced from or overlaps the first valley 1212 of the adjacent fresnel tooth 121. When the fresnel lens unit 12 is arranged on the exit surface of the lens body 11, the primary fresnel surfaces 1214 of the fresnel teeth 121 of the fresnel lens units 12 form the exit surface of the fresnel lens 10; when the fresnel lens unit 12 is provided at the incident surface of the lens body 11, the primary fresnel surfaces 1214 of the fresnel teeth 121 of the plural fresnel lens units 12 constitute the incident surface of the fresnel lens 10.

The surface type of each primary fresnel surface 1214 is a free-form surface; it will be appreciated that the shape of any portion of each primary fresnel surface 1214 can be adjusted to account for the fact that the shape of each primary fresnel surface 1214 is a free-form surface.

In the embodiment of the present application, the structures of the fresnel lens units 12 are different, and the primary fresnel surface 1214 formed by connecting the first valleys 1212 and the peaks 1211 of each fresnel tooth 121 has a free-form surface; note that the surface shape of each primary fresnel surface 1214 is a free curved surface so that any part of the surface shape of each primary fresnel surface 1214 can be freely set, and thus, in designing the fresnel lens 10, since each of the fresnel teeth 121 has a focusing function, according to the requirement that each fresnel lens unit 12 needs to focus the incident light in the detection region corresponding to the fresnel lens unit onto the sensing element 20, it is possible to proceed very carefully from the primary fresnel surface 1214 of each fresnel tooth 121 in this fresnel-lens unit 12, the shape of each portion of each primary fresnel surface 1214 and the corresponding parameters are designed accordingly, so that the primary fresnel surface 1214 is more flexible in design and, as such, the fresnel lens unit 12 can focus incident light in any direction after being designed, so that the fresnel lens unit 12 can focus the incident light in the detection zone corresponding to the fresnel lens unit onto the sensing element 20. Thus, when designing the fresnel lens 10, the surface type of the primary fresnel surface 1214 of each fresnel lens unit 12 can be correspondingly set according to the actual focusing requirement, and at this time, it is not required that the structure of each fresnel lens unit 12 is the same, so that the structure of each fresnel lens unit 12 can be correspondingly adjusted according to the surface type of the primary fresnel surface 1214, that is, the structure of each fresnel lens unit 12 can be freely set, so that the overall structure of the fresnel lens unit 12 and the design of the surface type of each primary fresnel surface 1214 in the fresnel lens unit 12 are more flexible and unlimited, so that the design of the fresnel lens 10 is more flexible, which helps to make the focuses of the fresnel lens units 12 be the same, that is, the fresnel lens units 12 can focus the incident light in the detection interval onto the sensing element 20, the focusing effect of the fresnel lens 10 is improved, and the fresnel lens 10 can meet the focusing requirements of higher requirements and larger detection range, thereby being beneficial to improving the identification sensitivity of the sensing element 20. The actual focusing requirement specifically includes the incident direction of the incident light in the detection zone corresponding to the fresnel lens unit 12 and the specific position of the sensing element 20, that is, the actual focusing requirement is a requirement that each fresnel lens unit 12 needs to focus the incident light in the detection zone corresponding to the fresnel lens unit onto the sensing element 20.

Moreover, the structure of each fresnel lens unit 12 can be adjusted according to actual conditions, and the surface type of each primary fresnel surface 1214 is a free-form surface, which is helpful for the fresnel lens 10 to focus incident light rays in a larger detection interval range when designing the fresnel lens 10, thereby increasing the detection range of the detector.

Alternatively, when the fresnel lens units 12 are provided at the exit surface of the lens body 11, each primary fresnel surface 1214 is the exit surface of each fresnel tooth 121, and the primary fresnel surfaces 1214 of all fresnel teeth 121 of each fresnel lens unit 12 form the exit surfaces of each fresnel lens unit 12, so that the primary fresnel surfaces 1214 of all fresnel lens units 12 form the exit surfaces of the fresnel lenses 10; because the surface type of the primary fresnel surface 1214 is set as a free-form surface and can be set according to actual requirements, the appearance surface of the exit surface side of the fresnel lens 10 can be set as a plane, a cylindrical surface, a spherical surface, a free-form surface and other complex curved surfaces according to actual requirements, and the design of the exit surface of the fresnel lens 10 is very flexible. Accordingly, the incident surface of the fresnel lens 10 can be flexibly designed to have a desired shape.

In one embodiment, referring to fig. 3 and fig. 4, a projection line of the peak 1211 on a vertical plane of the first direction Z is a closed free curve, wherein the vertical plane of the first direction Z is a plane perpendicular to the first direction Z. By adopting the above technical solution, when designing the fresnel lens 10, it is not necessary to define the shape of the peak 1211, that is, when designing the surface type of the primary fresnel surface 1214 of each fresnel lens unit 12 according to the requirement that each fresnel lens unit 12 needs to focus the incident light in the detection zone corresponding thereto onto the sensing element 20, the shape of the peak 1211 can be correspondingly designed and adjusted, so as to further improve the design flexibility of each fresnel tooth 121, so as to further improve the design flexibility of each fresnel lens unit 12, increase the focusing possibility of the fresnel lens unit 12, and thereby improve the focusing effect of the fresnel lens 10.

However, when the shape of the peak 1211 is not limited, the fresnel teeth 121 in each fresnel lens unit 12 are not limited to a fresnel ring, and the design of each fresnel tooth 121 is more flexible.

In one embodiment, referring to fig. 2 to 4, the projection lines of the first and second valleys 1212 and 1213 on the vertical plane in the first direction Z are both closed free curves. It is understood that, in a plane perpendicular to the first direction Z, the first and second valleys 1212 and 1213 of each fresnel tooth 121 are designed as a closed free curve, so that, when designing the fresnel lens 10, the shapes of the first and second valleys 1212 and 1213 need not be defined; as shown in fig. 2, on the vertical plane in the first direction Z, the projection surface of the primary fresnel surface 1214 of each fresnel tooth 121 is a free-form surface, that is, it is not necessary to set all the fresnel teeth 121 of each fresnel lens unit 12 as fresnel rings, and it is not necessary to design the primary fresnel surface 1214 of each fresnel ring as a circular ring surface.

In one embodiment, referring to fig. 3 and 4, the secondary fresnel surface 1215 of each fresnel tooth 121 is an arc-shaped surface, and the secondary fresnel surface 1215 is parallel to the first direction Z.

In general, when the fresnel teeth 121 of each fresnel lens unit 12 are designed to be circular, the secondary fresnel surfaces 1215 are all formed at an angle greater than 0 ° with respect to the main axis of the fresnel lens 10 due to design constraints, and when the fresnel lens 10 is injection molded by using a mold, the secondary fresnel surfaces 1215 are all formed at an angle greater than 0 ° with respect to the main axis of the fresnel lens 10, which may cause the fresnel lens 10 to be difficult to demold and damage the fresnel lens 10 after rough demold.

In this embodiment, the auxiliary fresnel surface 1215 of each fresnel tooth 121 is parallel to the first direction Z, that is, the auxiliary fresnel surface 1215 of each fresnel tooth 121 is parallel to the central axis of the fresnel lens 10, so that the fresnel lens 10 can be better demolded, and the damage of the fresnel lens 10 after demolding is reduced; in addition, each of the auxiliary fresnel surfaces 1215 is parallel to the first direction Z, and then on a projection plane of the fresnel lens 10 on a vertical plane of the first direction Z, all the primary fresnel surfaces 1214 on the fresnel lens 10 are continuously arranged, so that the fresnel lens 10 can focus more incident light, and the light extraction efficiency of the fresnel lens 10 is improved.

In one embodiment, referring to fig. 1, of the exit surface and the entrance surface of the lens body 11, the surface without the fresnel lens unit 12 is a plane, a cylindrical surface, a spherical surface, an ellipsoidal surface, or a free-form surface. It can be understood that, based on the above-mentioned design of the free-form surface of the primary fresnel surface 1214, the design surfaces of the incident surface side and the exit surface side of the fresnel lens 10 can be designed according to actual requirements, so that the surface type design of the design surfaces of the incident surface side and the exit surface side of the fresnel lens 10 is more flexible, and thus, the design of the design surface of the fresnel lens 10 is more flexible and more selective, which is helpful for improving the aesthetic property of the fresnel lens 10.

In an embodiment, referring to fig. 2, in the exit surface and the entrance surface of the lens body 11, the one provided with the fresnel lens unit 12 is sequentially divided into a first light adjusting area a, a second light adjusting area B, and a third light adjusting area C along the second direction Y, and the first light adjusting area a, the second light adjusting area B, and the third light adjusting area C are all provided with a plurality of fresnel lens units 12; the fresnel lens units 12 in the first light modulation area a, the second light modulation area B, and the third light modulation area C are respectively used to focus incident light rays in different detection sections from the second direction Y onto the sensor element 20. In any one of the first light adjusting area a, the second light adjusting area B, and the third light adjusting area C, the plurality of fresnel lens units 12 are arranged in sequence along the third direction X; the fresnel lens units 12 in the first dimming area a are sequentially arranged along the third direction X and are configured to focus incident light from different detection regions along the third direction X to the sensing element 20; the fresnel lens units 12 in the second dimming area B are sequentially arranged along the third direction X and are configured to focus incident light from different detection regions along the third direction X onto the sensing element 20; the fresnel lens units 12 in the third dimming area C are sequentially arranged along the third direction X, and are configured to focus incident light from different detection zones along the third direction X onto the sensor element 20. The first direction Z, the second direction Y, and the third direction X are mutually perpendicular to each other, where perpendicular refers to substantially perpendicular, and it is understood that there may be a certain deviation between the two mutually perpendicular directions.

As shown in fig. 1 and 2, 5 and 6, the first direction Z is a direction parallel to the central axis of the fresnel lens 10, and in a normal use state of the fresnel lens 10, the first light modulation region a, the second light modulation region B and the third light modulation region C are sequentially distributed in the second direction Y, and the fresnel lens units 12 in the first light modulation region a, the fresnel lens units 12 in the second light modulation region B and the fresnel lens units 12 in the third light modulation region C are used for focusing incident light from different detection sections in the vertical direction onto the sensor element 20; the fresnel lens units 12 in the first light modulation area a, the second light modulation area B and the third light modulation area C are all used for focusing incident light from different detection regions in the horizontal direction on the sensing element 20. Thus, the arrangement of the first light adjusting area a, the second light adjusting area B and the third light adjusting area C enables the multiple fresnel lens units 12 of the fresnel lens 10 to focus the incident light from the multiple different detection areas in the vertical direction and the horizontal direction onto the sensing element 20, so that the fresnel lens 10 can focus the incident light in the larger detection area range, and the detection range of the detector is enlarged.

In one embodiment, referring to fig. 2, the number of fresnel lens units 12 in the first dimming area a is greater than or equal to the number of fresnel lens units 12 in the second dimming area B, and the number of fresnel lens units 12 in the second dimming area B is greater than the number of fresnel lens units 12 in the third dimming area C. It can be understood that the sensing element 20 and the fresnel lens 10 of the detector are generally disposed at a position higher than the position of the moving object to be identified, based on the actual detection requirement of the detector, the plurality of fresnel lens units 12 in the first dimming area a need to focus incident light rays in more different detection intervals along the horizontal direction, the number of detection intervals of the incident light rays to be focused by the second dimming area B is substantially the same as the number of detection intervals corresponding to the first dimming area a, and the number of different detection intervals along the horizontal direction to be focused by the plurality of fresnel lens units 12 in the third dimming area C is smaller, so that the fresnel lens units 12 in the first dimming area a, the second dimming area B and the third dimming area C in this embodiment are designed according to the actual focusing requirement, and can better meet the actual use.

In one embodiment, referring to fig. 2, the first light modulation area a has 7 fresnel lens units 12 sequentially arranged in the third direction X, the second light modulation area B has 7 fresnel lens units 12 sequentially arranged in the third direction X, and the third light modulation area C has 5 fresnel lens units 12 sequentially arranged in the third direction X.

It should be noted that the incident directions of the incident light rays in the plurality of detection sections are different from each other, and the number of detection sections corresponds to the types of the incident light rays having different incident directions. Thus, by adopting the technical scheme, the arrangement of the first light adjusting area A, the second light adjusting area B and the third light adjusting area C realizes the focusing of incident light rays in 3 different incident directions in the second direction Y; the 7 fresnel lens units 12 in the first dimming area a realize focusing of incident light rays in 7 different incident directions in the third direction X, the 7 fresnel lens units 12 in the second dimming area B realize focusing of incident light rays in 7 different incident directions in the third direction X, and the 5 fresnel lens units 12 in the third dimming area C realize focusing of incident light rays in 5 different incident directions in the third direction X. Thus, the fresnel lens 10 provided in this embodiment realizes focusing of incident light rays in 19 different detection regions, and greatly improves the range corresponding to the incident light rays that can be focused by the fresnel lens 10, thereby increasing the detection range of the detector.

Alternatively, in the present embodiment, as shown in fig. 5 and 6, in a normal use state of the fresnel lens 10, the fresnel lens 10 is inclined downward by 30 ° with respect to the vertical direction, and it can be understood that the second direction Y is at an angle of 30 ° with respect to the vertical direction, and the vertical direction here should not be a limitation to the structure of the fresnel lens 10. As shown in fig. 5, the first light adjusting area a, the second light adjusting area B, and the third light adjusting area C are arranged such that the angle range of the incident light that can be focused by the fresnel lens 10 in the vertical direction is 112 °; as shown in fig. 6, the arrangement of the 7 focusing regions 12 of the first light modulation area a, the 7 focusing regions 12 of the second light modulation area B, and the third light modulation area C5 focusing regions 12 makes the angle range of the incident light rays that the fresnel lens 10 can focus in the horizontal direction 35 °.

In one embodiment, referring to fig. 2 to 4, a portion of the fresnel lens unit 12 only includes a plurality of fresnel teeth 121 arranged in series; the other part of the fresnel lens unit 12 includes a convex surface portion 122 and a plurality of fresnel teeth 121 arranged in series, and the plurality of fresnel teeth 121 arranged in series are arranged outward in order around the convex surface portion 122. The convex portion 122 and the fresnel teeth 121 are both disposed on the lens body 11.

In this embodiment, in the third direction X, the fresnel lens unit 12 located in the middle of the first dimming area a is an intermediate fresnel lens unit 12a, and the intermediate fresnel lens unit 12a includes an intermediate convex surface portion 122a and a plurality of fresnel teeth 121 sequentially arranged outward around the intermediate convex surface portion 122a, that is, the convex surface portion 122 of the intermediate fresnel lens unit 12a is the intermediate convex surface portion 122 a; the intermediate convex surface portion 122a has an optical axis that is perpendicular to the middle surface of the intermediate convex surface portion 122 a. The fresnel lens units 12 other than the intermediate fresnel lens unit 12a each have a central axis that is arranged parallel to the optical axis. Of the optical axis and the central axes, the optical axis is closest to the focal point of the fresnel lens 10; it can be understood that the intermediate fresnel lens unit 12a is configured to be opposite to the light-sensing surface of the sensing element 20, so that the position relationship between the sensing element 20 and the fresnel lens 10 can be designed more easily based on the design of the intermediate fresnel lens unit 12a, thereby improving the convenience of the design of the detector.

Example two

Referring to fig. 1 to 4, based on the design concept of the embodiment for the fresnel lens 10, the embodiment further provides a detector, which includes a sensing element 20 and the fresnel lens 10; the sensing elements 20 are arranged at intervals on one side of the emergent surface of the Fresnel lens 10, and the light-sensitive surfaces of the sensing elements 20 are arranged at the focusing position of the Fresnel lens 10; it should be noted that, in practical applications, when a human body moves in a detection zone of the detector, due to a temperature difference between a temperature of the human body and an ambient temperature, the human body generates infrared light, and the infrared light is incident to the fresnel lens 10, and the fresnel lens 10 focuses the infrared light to the sensing element 20, so that the sensing element 20 sends a corresponding electrical signal; wherein, the electric signal can be a control signal for opening a door, turning on a light, alarming and the like; the detector can also be used for identifying other moving objects except for human bodies. It should be further noted that the fresnel lens 10 in this embodiment is the same as the fresnel lens 10 in the first embodiment, and specific reference is made to the description of the fresnel lens 10 in the first embodiment, which is not repeated herein.

In the embodiment, by adopting the above technical solution, when designing the fresnel lens 10, the surface shape of the primary fresnel surface 1214 of each fresnel lens unit 12 can be set correspondingly according to the actual focusing requirement, so that the structure of each fresnel lens unit 12 can be adjusted correspondingly to the profile of its primary fresnel surface 1214, in this way, the design of the fresnel lens 10 is more flexible, which is helpful to make the focuses of the fresnel lens units 12 the same, that is, the fresnel lens units 12 can focus the incident light in the detection zone onto the sensing element 20, so as to improve the focusing effect of the fresnel lens 10, the fresnel lens 10 can meet the focusing requirements of higher requirements and larger detection range, thereby contributing to an improvement in the recognition sensitivity of the sensor element 20 and thus to an improvement in the detection sensitivity and detection effect of the detector.

The rest of this embodiment is the same as the first embodiment, and the unexplained features in this embodiment are explained by the first embodiment, which is not described herein again.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.