CN102279426B - Fresnel lens, passive infrared detector and security system - Google Patents
Fresnel lens, passive infrared detector and security system Download PDFInfo
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- CN102279426B CN102279426B CN 201110137178 CN201110137178A CN102279426B CN 102279426 B CN102279426 B CN 102279426B CN 201110137178 CN201110137178 CN 201110137178 CN 201110137178 A CN201110137178 A CN 201110137178A CN 102279426 B CN102279426 B CN 102279426B
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Abstract
The invention is applicable in the optical field and provides a Fresnel lens, a passive infrared detector and a security system. The Fresnel lens comprises a plurality of strip-shaped Fresnel lens units which are the same in structure; the plurality of strip-shaped Fresnel lens units are arranged in parallel in turn along a width direction thereof; each Fresnel lens unit comprises an exit surface and a smooth incidence surface; an arc-shaped exit region is arranged on the exit surface; a plurality of first concentric circular arc tooth grains are arranged above the arc-shaped exit region in turn along the height direction of the Fresnel lens unit; circle centres of the first tooth grains are superposed with the circle centre of the arc-shaped exit region; the depths of the plurality of first tooth grains are equal; and the distances between every two adjacent first tooth grains are progressively decreased outwardly along the centre of the arc-shaped exit region. Because the arc tooth grains are arranged above the arc-shaped exit region, the effective detection height of the lens within a detectable distance is higher. Because infrared ray emitted by a lower movable object cannot be received by the lens, unnecessary alarm is avoided.
Description
Technical field
The invention belongs to optical field, relate in particular to a kind of Fresnel Lenses, passive infrared detector and safety-protection system.
Background technology
Fresnel Lenses is mainly annotated to press by polyolefine material and is formed, and lens surface is simultaneously the light face, and another side has been delineated a plurality of ascending concentric circles grooves.Fresnel Lenses is equivalent to the convex lens of infrared ray and visible light to a certain extent, and its spotlight effect is good, and cost is more much lower than common convex lens, easy-formation in production, thereby be widely used.Modal is to be installed in the detector of safety-protection system as condenser lens, Fresnel Lenses is divided into several area pellucidas and dark space with search coverage, the mobile object that enters search coverage passes area pellucida and dark space, infrared ray that it sends focuses on the passive infrared sensing element of detector through Fresnel Lenses, and this element heat that can change is released infrared signal and is transferred to alarm center.Yet existing detector all can produce alerting signal to the mobile object in any intrusion detection zone, and when having toy or children to swarm into, alarm also can be reported to the police, for the staff brings unnecessary trouble.
Summary of the invention
The object of the present invention is to provide a kind of Fresnel Lenses, make and adopt the warning device of these lens can not produce false alarm when having toy or children to enter monitoring section.
The present invention is achieved in that a kind of Fresnel Lenses, comprises the Fresnel Lenses unit of the bar shaped that a plurality of structures are identical, and the Fresnel Lenses unit of described a plurality of bar shapeds is arranged in parallel successively along its Width;
Described each Fresnel Lenses unit comprises exit facet and the level and smooth plane of incidence;
Described exit facet is provided with a cabochon outgoing district;
Above described cabochon outgoing district and be provided with successively the first groove of a plurality of concentric circles arcs along the short transverse of described Fresnel Lenses unit;
The groove of minute quantity is not set or arranges below described cabochon outgoing district;
The center of circle of described the first groove overlaps with the center of circle in described cabochon outgoing district;
The tooth depth of described a plurality of the first grooves all equates;
Spacing between adjacent the first groove outwards is gradual successively decreasing along the center in cabochon outgoing district.
The height of each Fresnel Lenses unit is 15～20mm, and width is 3～4mm;
The quantity of described the first groove is 35～50;
The tooth depth of described the first groove is 0.15～0.25mm;
The radius-of-curvature in described cabochon outgoing district is 1.2～1.4mm, and center thickness is 0.6～0.7mm.
Another object of the present invention is to provide a kind of passive infrared detector that comprises above-mentioned Fresnel Lenses.
Another object of the present invention is to provide a kind of safety-protection system, comprise detector and the alarm that is connected with described detector, described detector adopts above-mentioned passive infrared detector.
The present invention is arranged to opening up structure with Fresnel Lenses, namely above the cabochon outgoing district of Fresnel Lenses unit, a plurality of concentric circles arc grooves is set, and does not arrange or arrange the groove of minute quantity below cabochon outgoing district.This structure makes these lens be applicable to early detection, and within detectable distance, it is higher that it effectively surveys aspect ratio, the infrared ray that lower mobile object (as toy, children) sends can't be received and focus on by these lens on the infrared sensing element at rear, has therefore avoided unnecessary warning.
Description of drawings
Fig. 1 is the main TV structure schematic diagram of the Fresnel Lenses that provides of the embodiment of the present invention;
Fig. 2 (a) is the side-looking structural representation of the Fresnel Lenses that provides of the embodiment of the present invention;
Fig. 2 (b) is the side-looking structure partial enlarged drawing of the Fresnel Lenses that provides of the embodiment of the present invention;
Fig. 3 is the detection principle schematic diagram of the Fresnel Lenses that provides of the embodiment of the present invention;
Fig. 4 is the detection principle schematic diagram of traditional Fresnel Lenses.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.
The invention provides a kind of Fresnel Lenses, comprise the Fresnel Lenses unit of the bar shaped that a plurality of structures are identical, the Fresnel Lenses unit of a plurality of bar shapeds is arranged in parallel successively along its Width;
Each Fresnel Lenses unit comprises exit facet and the level and smooth plane of incidence;
Exit facet is provided with a cabochon outgoing district;
Above cabochon outgoing district and be provided with successively the first groove of a plurality of concentric circles arcs along the short transverse of Fresnel Lenses unit;
The center of circle of the first groove overlaps with the center of circle in cabochon outgoing district;
The tooth depth of a plurality of the first grooves all equates;
Spacing between adjacent the first groove outwards is gradual successively decreasing along the center in cabochon outgoing district.
The present invention also provides a kind of passive infrared detector that comprises above-mentioned Fresnel Lenses.
The present invention also provides a kind of safety-protection system, comprises detector and the alarm that is connected with detector, and this detector adopts above-mentioned passive infrared detector.
Be described in detail below in conjunction with the specific implementation of specific embodiment to a kind of Fresnel Lenses of the present invention:
Fig. 1 shows the main TV structure schematic diagram of the Fresnel Lenses that the embodiment of the present invention provides, Fig. 2 (a) shows the side-looking structural representation of the Fresnel Lenses that the embodiment of the present invention provides, Fig. 2 (b) shows the side-looking structure partial enlarged drawing of the Fresnel Lenses that the embodiment of the present invention provides, Fig. 3 shows the detection principle schematic diagram of the Fresnel Lenses that the embodiment of the present invention provides, Fig. 4 shows the detection principle schematic diagram of traditional Fresnel Lenses, for convenience of explanation, only show the part relevant to the present embodiment.
As shown in Figure 1, the Fresnel Lenses that provides of the present embodiment comprises a plurality of structures identical strip Fresnel Lenses unit 1.A plurality of Fresnel Lenses unit 1 connects side by side, and namely a plurality of lens units 1 are arranged in parallel successively along the Width of lens unit, forms a combined Fresnel Lenses.With reference to accompanying drawing 2(a), 2(b), accompanying drawing 2(b wherein) be accompanying drawing 2(a) in the enlarged drawing of dotted line institute enclosing region.Each Fresnel Lenses unit 1 comprises the level and smooth plane of incidence 11 and exit facet 12.The lower end of exit facet 12 has cabochon outgoing district 121, it is equivalent to the central area of the exit facet of convex lens, be distributed with the first groove 122 of the concentric circles arc of a plurality of projections above cabochon outgoing district 121, this first groove 122 is that 1 short transverse is arranged in order from bottom to top along the Fresnel Lenses unit, and the center of circle of this first groove 122 overlaps with the center of circle in cabochon outgoing district 121.Distance apart from cabochon outgoing district 121 is far away, and the distribution of the first groove 122 is more intensive, and the tooth depth of all the first grooves 122 is identical.
This Fresnel Lenses can form by once molding formed mode, namely in once molding formed many groups of first grooves 122 of arranging side by side in a surface of the lens matrix material of sheet and cabochon outgoing district 121, unprocessed level and smooth one side is as the plane of incidence 11 of these lens, and the one side in mold pressing groove and cabochon outgoing district is as the exit facet 12 of these lens.
Install for the ease of user side, the size and dimension of the lens matrix material of sheet can be according to the requirements set of user side, as shown in Figure 1, the first groove 122 and cabochon outgoing district 121 can only be positioned at the first half zone of whole matrix, the latter half zone does not need processing, and this is only to adapt for the structure with the user side detector.
Continuation is with reference to accompanying drawing 1, and as further improvement of this embodiment, the below in cabochon outgoing district 121 also can arrange some concentric the second grooves 123, but the quantity of the second groove 123 will be much smaller than the quantity of the first groove 122.To guarantee that these lens have anti-pet, children's function.
The present embodiment arranges a plurality of concentric circles arc grooves above the cabochon incidence zone of each Fresnel Lenses unit, and does not arrange or arrange the groove of minute quantity below cabochon outgoing district.As shown in Figure 3, this Fresnel Lenses is within detectable area, it is higher that it effectively surveys aspect ratio, if mobile object 31(such as toy, children) height lower, its infrared ray that sends can't be received and focus on by these lens on the infrared sensing element 32 at rear.Therefore, the Fresnel Lenses that provides of the present embodiment can play and prevent that warning device from carrying out the effect of false alarm to toy and children.The infrared ray that traditional Fresnel Lenses can send the mobile object 41 of any height focuses on the infrared sensing element 42 at rear, and then reports to the police, and as shown in Figure 4, so just makes troubles for the staff.
As a kind of preferred implementation of the present embodiment, the overall height of each Fresnel Lenses unit can be limited between 15～20mm, width is limited between 3～4mm.In the altitude range of 15～20mm, the quantity of the first groove can be set as 35～50, take 45～50 as optimal number, and the diameter of cabochon incidence zone can be set as 4～6mm.When these lens have the second groove, can it be 1～5 with the restricted number of the second groove, take 2～3 as optimal number.And the total quantity of Fresnel Lenses unit can rationally arrange according to the demand of use side, is specifically as follows 15.So just, obtained to have appropriate size, the suitable Fresnel Lenses of groove density.
As the further improvement of above-mentioned preferred implementation, the tooth depth of the first groove can be restricted to 0.15～0.25mm; The center thickness of cabochon exit facet is restricted to 0.6～0.7mm, the radius-of-curvature of cabochon exit facet is restricted to 1.2～1.4mm, take 1.3mm as optimum dimension.
Can have the detection range of 3～15m according to the Fresnel Lenses of the described design parameter making of above-mentioned implementation, in this detection range, it surveys height can be greater than 0.8m.This Fresnel Lenses is arranged in the detector of warning device mainly as ultrared condenser lens, is appreciated that installing rear the first groove is up, and the second groove is down.As Fig. 3, for be in apart from the vertical range of warning device be in the monitored area of 3～15m and height greater than the mobile object of 0.8m, this warning device can Normal Alarm.Be the regional interior and mobile object of height below 0.8m of 0～15m and be in apart from the vertical range of warning device, the infrared ray that these lens can not send this mobile object 31 focuses on the infrared sensing element 32 at rear, so just can avoid unnecessary warning.
The above is only preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., within all should being included in protection scope of the present invention.
Claims (6)
1. a Fresnel Lenses, is characterized in that, comprises the Fresnel Lenses unit of the bar shaped that a plurality of structures are identical, and the Fresnel Lenses unit of described a plurality of bar shapeds is arranged in parallel successively along its Width;
Described each Fresnel Lenses unit comprises exit facet and the level and smooth plane of incidence;
Described exit facet is provided with a cabochon outgoing district;
Above described cabochon outgoing district and be provided with successively the first groove of a plurality of concentric circles arcs along the short transverse of described Fresnel Lenses unit;
The groove of minute quantity is not set or arranges below described cabochon outgoing district;
The center of circle of described the first groove overlaps with the center of circle in described cabochon outgoing district;
The tooth depth of described a plurality of the first grooves all equates;
Spacing between adjacent the first groove outwards is gradual successively decreasing along the center in cabochon outgoing district;
The height of each Fresnel Lenses unit is 15～20mm, and width is 3～4mm;
The quantity of described the first groove is 35～50;
The tooth depth of described the first groove is 0.15～0.25mm;
The radius-of-curvature in described cabochon outgoing district is 1.2～1.4mm, and center thickness is 0.6～0.7mm.
2. Fresnel Lenses as claimed in claim 1, is characterized in that, below described cabochon outgoing district and also be provided with the second groove of several concentric circles arcs along the short transverse of described Fresnel Lenses unit,
The center of circle of described the second groove overlaps with the center of circle in described cabochon outgoing district;
The quantity of described the second groove is far fewer than the quantity of described the first groove.
3. Fresnel Lenses as claimed in claim 2, is characterized in that, the quantity of described the second groove is 2～3.
4. Fresnel Lenses as claimed in claim 1, is characterized in that, described Fresnel Lenses unit has 15.
5. passive infrared detector that comprises the described Fresnel Lenses of claim 1 to 4 any one.
6. a safety-protection system, comprise detector and the alarm that is connected with described detector, it is characterized in that, described detector adopts passive infrared detector claimed in claim 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110137178 CN102279426B (en) | 2011-05-25 | 2011-05-25 | Fresnel lens, passive infrared detector and security system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110137178 CN102279426B (en) | 2011-05-25 | 2011-05-25 | Fresnel lens, passive infrared detector and security system |
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| Publication Number | Publication Date |
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| CN102279426A CN102279426A (en) | 2011-12-14 |
| CN102279426B true CN102279426B (en) | 2013-06-19 |
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| CN 201110137178 Active CN102279426B (en) | 2011-05-25 | 2011-05-25 | Fresnel lens, passive infrared detector and security system |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7266274B2 (en) * | 2018-09-12 | 2023-04-28 | オプテックス株式会社 | Security sensor device |
| CN113777678A (en) * | 2021-08-30 | 2021-12-10 | 深圳市百康光电有限公司 | Fresnel lens and detector |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL122846A (en) * | 1998-01-04 | 2003-06-24 | Visonic Ltd | Passive infra-red intrusion sensing system covering downward zone |
| CA2300644C (en) * | 2000-03-10 | 2009-07-14 | Digital Security Controls Ltd. | Pet resistant pir detector |
| GB2431987B (en) * | 2005-11-03 | 2011-07-06 | Pyronix Ltd | Detector and optical system |
| US7151639B2 (en) * | 2005-05-11 | 2006-12-19 | Everspring Industry, Co., Ltd. | Thin-type spherical lens |
| CN101915947B (en) * | 2010-08-24 | 2014-12-10 | 深圳市豪恩安全科技有限公司 | Fresnel lens, detector and security system |
| CN202166757U (en) * | 2011-05-25 | 2012-03-14 | 深圳市豪恩安全科技有限公司 | Fresnel lens, passive infrared detector and security system |
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Address after: Shenzhen City, Guangdong Province, Guangming New District 518000 000 Daiheng Guangming high tech Industrial Park, building fourth, building fifth, first floor Patentee after: Zhong An (Shenzhen) Co., Ltd. Address before: 518106, Guangdong, Shenzhen Guangming District, public Chang Road (Shenzhen Village) security manufacturing (China) Industrial Park, 4, 5 Patentee before: Shenzhen Haoen Safety Technology Co., Ltd. |
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| CP01 | Change in the name or title of a patent holder |
Address after: 518000 fourth buildings and fifth first floor of Wan Dai Heng Guangming hi tech Industrial Park, Guangming New District, Shenzhen, Guangdong Patentee after: Shenzhen Haoen Safety Technology Co., Ltd. Address before: 518000 fourth buildings and fifth first floor of Wan Dai Heng Guangming hi tech Industrial Park, Guangming New District, Shenzhen, Guangdong Patentee before: Zhong An (Shenzhen) Co., Ltd. |
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