CN2710008Y - Far and near automatic focus camera - Google Patents

Abstract

The utility model relates to a far and near full-automatic focusing camera used on a monitoring camera. The imaging lens assembly comprises a first concave-convex lens, a second concave-convex lens, a third concave lens and a fourth convex lens which are arranged in sequence, wherein the curvature radius of the first concave-convex lens and the curvature radius of the second concave-convex lens at the image capturing side are smaller than that of the image forming side; the curvature radius of the third concave lens at the image capturing side is larger than that at the image forming side; the fourth convex lens both sides have the same camber, by foretell structural design, the utility model discloses a lens group in case the equipment finishes the back, does not need any focus to change the action, can receive the object image via image receiving unit group and directly convey to monitor department and show clear image, so reduce the cost of manufacture, more can reduce whole volume to promote the commercial competitiveness of product.

Description

Far and near automatic focus camera

technical field

The utility model relates to a far-near automatic focus camera, in particular to a far-near automatic focus camera used on a surveillance camera.

Background technique

Generally, most of the surveillance cameras used to monitor the situation of the site have a lens group, an image processing unit group, and an image receiving unit group that can adjust the telescopic focus. Among them, the excellence of the traditional surveillance camera mostly depends on the lens group, which determines the quality of the lens. It depends on the number of lenses, lens transmittance, coating and grinding, and mechanical devices. In order to achieve the purpose of zooming and imaging, mechanical devices are usually the most important driving unit in a lens group structure. Using such a driving unit makes All kinds of lenses in the lens group can change the focal length to achieve the purpose of clear imaging.

However, most of the above-mentioned mechanical devices must be equipped with a driving circuit to drive their actions, and the circuit board of the driving circuit and the mechanical device itself occupy a large volume, making it impossible to reduce the size of a general surveillance camera. In addition, the additional driving circuit And mechanical device will cause the increase of surveillance camera production cost, cause surveillance camera price to be unable to drop and be popularized.

Utility model content

The purpose of this utility model is to improve the congenital defect in the structure of the above-mentioned conventional surveillance camera, so as to provide a far-near automatic focusing camera that can achieve the purpose of automatic zooming and imaging without mechanical devices.

In order to achieve the above object, the utility model adopts the following technical solutions: the fully automatic focusing camera of the utility model includes a lens group, an image receiving unit group, an illuminating device and a photosensitive module arranged in an accommodating housing, and is characterized in that:

The lens group includes a first concave-convex lens, a second concave-convex lens, a third concave lens and a fourth convex lens arranged in sequence; wherein, the radius of curvature of the first concave-convex lens and the second concave-convex lens on the object side is smaller than that on the imaging side Radius of curvature; the third concave lens is a biconcave lens, and its radius of curvature on the image-taking object side is larger than that on the imaging side; the fourth convex lens is a biconvex lens, and its two sides have the same curvature.

The function of the eyeglass of the first concave-convex lens is to shorten its parallel light and focus on the eyeglasses of the second concave-convex lens and the third concave lens when light enters the lens; The amount of light and the light path are properly adjusted so that the photosensitive module can obtain accurate and clear images.

With the above-mentioned structural design, once the lens group of the present invention is assembled, the object image can be received by the image receiving unit group and directly sent to the monitor to display a clear image without any focal length change action, not only The mechanical device for driving the zoom of the lens group can be omitted to reduce the production cost, and the overall volume can be reduced to enhance the commercial competitiveness of the product.

Description of drawings

FIG. 1 is a schematic structural view of the lens group of the far-near automatic focusing camera of the present invention.

Detailed ways

The main feature of the utility model lies in the structure of the lens group, which only needs to use 4 lenses to make the long-distance or short-distance imaging target be clearly imaged through the photosensitive module CCD or CMOS. This phenomenon is like the human retinal nerve The system can completely "automatically" adjust the clarity of the captured object, just like the use of a telescope. Once the focal length is adjusted, within a certain distance range, objects no matter how far or near can be clearly identified.

Since the image receiving unit group, lighting device and photosensitive module of the utility model are all the same as the conventional structure for receiving images, providing illumination and sensing luminosity, the description is omitted, and only the lens group of the utility model is now described. Describe in detail.

As shown in Figure 1, the lens group of the near and far automatic focusing camera of the present utility model comprises the first concave-convex lens 10, the second concave-convex lens 11, the 3rd concave-convex lens 12 and the 4th convex lens 13 arranged in order, wherein, the first The radius of curvature of the meniscus lens 10 and the second meniscus lens 11 on the imaging object side is smaller than the curvature radius of the imaging side;

The third concave lens 12 is a biconcave lens, and its radius of curvature on the image-taking object side is greater than that on the imaging side;

The fourth convex lens 13 is a biconvex lens with the same curvature on both sides.

Among them, the function of the first concave-convex lens 10 is to shorten the parallel light of the image-taking object, and focus it on the second concave-convex lens 11 and the third concave lens 12, and then collect the image to the image receiver through the fourth convex lens 13. unit.

The arrangement of the lenses of the lens group is set according to the lens imaging theory of physics, namely:

$\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}$

Where f = focal length; u = object distance; v = image distance.

The combination of each lens is arranged according to the light projection principle of object distance=image distance and object length=image length.

For example, when the object is beyond twice the focal length, the imaging will be reduced; when the object is at twice the focal length, the imaging will be the same size as the object; It will be magnified; when the object is at one focal length, the image will be at infinity; if the object is within one focal length, there will be only a virtual image; and when the object is at infinity, the image will be at the focus.

The central thickness of the first meniscus lens 10 in this embodiment is 5.1±0.1 mm, the curvature on the image capturing object side is 14.155, and the curvature on the other side is 201.8.

The center thickness of the second meniscus lens 11 is 3.1±0.1 mm, the curvature on the side of the image taking object is 10.544, and the curvature on the other side is 17.298.

The center thickness of the third concave mirror 12 is 0.7±0.1mm, the curvature on the side of the image taking object is 731.1, and the curvature on the other side is 7.691.

The central thickness of the fourth convex lens 13 is 3.5±0.1 mm, and the curvature of both sides is 21.33.

The shortest distance between the center point of the first meniscus lens 10 and the second meniscus lens 1 is 0.1±0.1 mm, the shortest distance between the second meniscus lens 11 and the third concave lens 12 is 1.27 mm, and the third concave lens 12 and the fourth convex lens 13 The shortest distance between the central point of the fourth convex lens 13 and the image receiving unit is 12.64mm.

It has been proved by practice that the far and near automatic focus camera of the present invention can obtain clear images without changing the relative distance between the lenses after the setting of each lens of the lens group, that is, the distance is determined. , the lens group of the present utility model does not need any mechanical device for zooming to obtain a clear image, so that not only the mechanical device and the circuit for driving the mechanical device can be saved to reduce the manufacturing cost, but also the overall volume can be reduced due to the reduction of parts. To enhance the competitiveness of products.

Claims (6)

1. A far and near automatic focusing camera, comprising a lens group, an image receiving unit group, an illumination device and a photosensitive module arranged in an accommodating housing, characterized in that: The lens group includes a first concave-convex lens, a second concave-convex lens, a third concave lens and a fourth convex lens arranged in sequence, wherein the radius of curvature of the first concave-convex lens and the second concave-convex lens on the image taking object side is smaller than that on the imaging side radius of curvature; The third concave lens is a biconcave lens, and its radius of curvature on the image-taking object side is larger than that on the imaging side; The fourth convex lens is a biconvex lens with the same curvature on both sides. 2. The far-near fully automatic focusing camera according to claim 1, wherein the central thickness of the first concave-convex lens is 5.1±0.1 mm, the curvature on the side of the image-capturing object is 14.155, and the curvature on the other side is 201.8. 3. The far-near fully automatic focusing camera as claimed in claim 1, characterized in that the central thickness of the second concave-convex lens is 3.1±0.1mm, the curvature on the side of the image-capturing object is 10.544, and the curvature on the other side is 17.298. 4. The far-near fully automatic focusing camera as claimed in claim 1, characterized in that the central thickness of the third concave mirror is 0.7±0.1 mm, the curvature on the side of the image-taking object is 731.1, and the curvature on the other side is 7.691. 5. The far-near fully automatic focusing camera as claimed in claim 1, characterized in that the central thickness of the fourth convex lens is 3.5±0.1 mm, and the curvature of both sides is 21.33. 6. The far-near fully automatic focusing camera according to claim 1, wherein the shortest distance between the center points of the first concave-convex lens and the second concave-convex lens is 0.1±0.1mm, and the center point of the second concave-convex lens and the third concave-convex lens The shortest distance is 1.27mm, the shortest distance between the center of the third concave lens and the fourth convex lens is 5.4±0.1mm, and the distance between the center of the fourth convex lens and the image receiving unit is 12.64mm.

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