CN203965714U - A kind of long-focus long-wave infrared continuous zoom lens - Google Patents

Abstract

The utility model discloses a kind of long-focus long-wave infrared continuous zoom lens, from object space to image space, have successively five groups of lens, comprising: having the front fixedly group of positive light coke, is the falcate germanium positive lens of a slice convex surface towards object space; The zoom group with negative power is the concave concave germanium negative lens of a slice; The compensation group with positive light coke is the lenticular germanium positive lens of a slice; The rear fixedly group with negative power, for a slice convex surface is glass negative lens towards the falcate coloured glaze of image space; The focusing group with positive light coke is the falcate germanium positive lens of a slice convex surface towards object space.The utility model can be within the scope of 40mm～160mm continuous vari-focus, F number is held constant at 1.0 simultaneously, is applicable to the long wave uncooled detector of resolution 640 * 480 Pixel size 25 μ m; Zoom and compensation group shift motion is short and curve smoothing in complete burnt section, optical axis stable is high, has good imaging effect.

Description

A kind of long-focus long-wave infrared continuous zoom lens

Technical field

The utility model belongs to optical technical field, relates to a kind of long-focus long-wave infrared continuous zoom lens for LWIR Uncooled detector.

Background technology

The application of technology is more and more extensive in recent years.Long wave uncooled detector is lightweight, volume is little, and along with the reduction of cost, its range of application is from the military civil area that spreads to, such as security protection, industry, medical treatment etc.Common tight shot and double-view field camera lens can not meet user demand under some occasion.The continuous magnification lens that this patent relates to, is used five eyeglasses, and mobile wherein two eyeglasses, realize the smooth change of focal length, thereby can better realize discovery, tracking and the identification to target.The utility model compact conformation, transmitance be high, be easy to volume production, therefore has good application prospect.

Utility model content

The technical problems to be solved in the utility model is to provide a kind of long-focus, and aperture is constant, the total length of optics, and volume is little, the long-focus long-wave infrared continuous zoom lens debug conveniently, image quality being high.Its service band is 8～12 microns, and focal length is 40mm～160mm, and F number is 1.0, and adaptive resolution is 640 * 480, the uncooled detector that Pixel size is 25 microns, optical system overall length 310mm, maximum caliber 170mm.

To achieve these goals, the technical solution adopted in the utility model is:

A long-focus long-wave infrared continuous zoom lens, is comprised to image space successively by object space, front fixedly group, zoom group, compensation group, rear fixedly group, focusing group and explorer portion;

Described front fixedly group has positive light coke, is the falcate germanium single crystal positive lens of a slice convex surface towards object space, and surface type is sphere;

Described zoom group has negative power, is a slice double concave germanium single crystal negative lens, and its side towards image space is aspheric surface, total shift motion 57.98mm of described lens;

Described compensation group has positive light coke, is the lenticular germanium single crystal positive lens of a slice, and its side towards object space is aspheric surface, total shift motion 33.54mm of described lens;

Described rear fixedly group has negative power, is the falcate germanium single crystal positive lens of a slice convex surface towards image space, and its convex surface is diffraction surfaces;

Described focusing group has positive light coke, is the falcate germanium single crystal positive lens of a slice convex surface towards object space, and its convex surface is aspheric surface, total shift motion 4.5mm of described lens;

After described focusing group, be long wave uncooled detector part, comprise protecting window and image planes; Aperture diaphragm, in compensation group and rear fixedly between group, keeps constant in zoom process.

Described camera lens meets following parameter:

Effective focal length EFL=40～the 160mm of described camera lens, F number=1.0, optical system overall length=310mm, adaptive detector resolution 640 * 490, Pixel size 25 μ m

The average MTF>0.5@20lp/mm of the full visual field of described camera lens.

Aspheric surface in the eyeglass of described camera lens meets following expression formula:

$z=\frac{c{r}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+{\mathrm{\α}}_2{r}^4+{\mathrm{\α}}_3{r}^6+{\mathrm{\α}}_4{r}^8+{\mathrm{\α}}_5{r}^{10}+{\mathrm{\α}}_6{r}^{12}$

Wherein z is aspheric surface along optical axis direction when highly for the position of r, apart from the distance rise on aspheric surface summit, and the vertex curvature of c presentation surface, k is circular cone coefficient, α ₂, α ₃, α ₄, α ₅, α ₆for high order aspheric surface coefficient.

Diffraction surfaces in the eyeglass of described camera lens meets following expression formula:

Φ＝A ₁ρ ²+A ₂ρ ⁴

The position phase that wherein Φ is diffraction surfaces, ρ=r/r _n, r _nthe planning radius of diffraction surfaces, A ₁, A ₂phase coefficient for diffraction surfaces.

The beneficial effects of the utility model are: complete burnt section aperture 1.0, and in zoom process, aperture is constant, has 4 times of zoom ratios, and optical system overall length is 310mm, maximum caliber 170mm.Compact conformation, zoom curve smoothing, the maximum amount of movement of eyeglass is 57.98mm.Zoom group and compensation group all only have a slice lens, can better guarantee the optical axis stable in zoom process like this.Use refraction type optical texture simultaneously, need not adjust catoptron, debug easyly, be easy to volume production.In whole zooming range, image quality is good, the average MTF>0.5@20lp/mm of full visual field.

Accompanying drawing explanation

Fig. 1 is the optical system diagram of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 160mm;

Fig. 2 is the point range figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 160mm;

Fig. 3 is the optical transfer function figure (cut-off resolution be 20llp/mm) of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 160mm;

Fig. 4 is the astigmatism distortion figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 160mm;

Fig. 5 is the optical system diagram of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 100mm;

Fig. 6 is the point range figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 100mm;

Fig. 7 is the optical transfer function figure (cut-off resolution be 20llp/mm) of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 100mm;

Fig. 8 is the astigmatism distortion figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 100mm;

Fig. 9 is the optical system diagram of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 40mm;

Figure 10 is the point range figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 40mm;

Figure 11 is the optical transfer function figure (cut-off resolution be 20llp/mm) of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 40mm;

Figure 12 is the astigmatism distortion figure of the focal length of the long-focus long-wave infrared continuous zoom lens that provides of the utility model while being 40mm;

Wherein, 200-object space, fixing group before 110-, 120-zoom group, 130-compensation group, 140-aperture diaphragm, fixing group after 150-, 160-focusing group, 310-detector assembly, 312-detector protecting window, 314-image planes, S1～S10 is each surfaces of lens.

Embodiment

Below in conjunction with accompanying drawing, by embodiment, the utility model is described in further details.

This embodiment is the example that the utility model is applied to long wave non-refrigeration type resolution 640 * 480 pixel dimension 25 μ m gazing type focus planardetectors.

Fig. 1, Fig. 5, Fig. 9 are respectively the utility model at focal length 160mm, optical system diagram when 100mm and 40mm.As shown in Figure 1, this enforcement is comprised of front fixedly group 110, the zoom group 120 of negative power, the rear fixedly group 150 of the compensation group 130 of positive light coke, negative power, the focusing group 160 of positive light coke and the last detector 310 of positive light coke.

Front fixing group 110 is first lens, is the positive lens of convex surface towards object space, and material is germanium single crystal, and S2 surface is aspheric surface; Zoom group 120 i.e. the second lens, and for double concave is negative lens, material is germanium single crystal, and S4 surface is aspheric surface.These lens are mobile eyeglasses, have played the effect of zoom in zoom process, and moving curve is 5 para-curves, total shift motion 57.98mm; Compensation group 130 i.e. the 3rd lens, are lenticular positive lens, and material is germanium single crystal, and S5 surface is aspheric surface.These lens are mobile eyeglasses, and when zoom arrangement of mirrors sheet moves, thereby compensation arrangement of mirrors sheet is done corresponding movement assurance image planes invariant position, and moving curve is straight line, total shift motion 33.54mm; Rear fixing group 150 i.e. the 4th lens, are the negative meniscus of convex surface towards image space, and material is that coloured glaze is glass, and S8 surface is diffraction aspheric surface.Focusing group 160 i.e. the 5th lens, are the falcate positive lens of convex surface towards image space, and material is germanium single crystal, and wherein S9 face is aspheric surface.These lens are mobile eyeglasses, when target range changes and when working temperature changes, can again focus on this eyeglass, and total shift motion 4.5mm; Long wave uncooled detector 310 comprises: protecting window 312, and imaging surface 314, resolution is 640 * 480, Pixel size 17 μ.The aperture diaphragm 140 of system, in compensation group and rear fixedly between group.In zoom process, the aperture of the diaphragm is constant, thereby guarantees that aperture is constant.

In above five lens, first lens S1 plated surface diamond-like carbon film, because this is surface exposed, needs coating diamond-like carbon film carbon film to play protective effect, and anti-reflection film is all plated on all the other S2～S10 surfaces.

Table 1 be the utility model at focal length 160mm, 100mm, Optic structure parameter during 40mm:

Table 1

The aspheric surface of mentioning in above eight lens, is even aspheric surface, and its expression formula is as follows

$z=\frac{c{r}^2}{1+\sqrt{1-(1+k)c^2{r}^2}}+{\mathrm{\α}}_2{r}^4+{\mathrm{\α}}_3{r}^6+{\mathrm{\α}}_4{r}^8+{\mathrm{\α}}_5{r}^{10}+{\mathrm{\α}}_6{r}^{12}$

Wherein z is aspheric surface along optical axis direction when highly for the position of r, apart from the distance rise on aspheric surface summit, and the vertex curvature of c presentation surface, k is circular cone coefficient, α ₂, α ₃, α ₄, α ₅, α ₆for high order aspheric surface coefficient.

Table 2 is surperficial S2, S4, and S5, S8, the asphericity coefficient of S9:

Table 2

The diffraction surfaces of mentioning in above five lens, its expression formula is as follows:

Φ＝A ₁ρ ²+A ₂ρ ⁴

The position phase that wherein Φ is diffraction surfaces, ρ=r/r _n, r _nthe planning radius of diffraction surfaces, A ₁, A ₂phase coefficient for diffraction surfaces.

Table 3 is the diffraction coefficient of surperficial S8;

Table 3

Surface	?	?	?
				S8	15.260978	-2.0851126	0.36539816

Below with reference to Aberration Analysis figure, effect of the present utility model is done to further detailed description.

Fig. 2-Fig. 4 is the specific embodiment of the long-wave infrared continuous zoom lens described in Fig. 1 Aberration Analysis figure when long burnt state, and Fig. 2 is that point range figure, Fig. 3 are that MTF figure, Fig. 4 are curvature of field distortion figure;

Fig. 6 Fig. 8 is the specific embodiment of the long-wave infrared continuous zoom lens described in Fig. 5 Aberration Analysis figure when middle burnt state, and Fig. 6 is that point range figure, Fig. 7 are that MTF figure, Fig. 8 are curvature of field distortion figure;

Figure 10 Figure 12 is the specific embodiment of the long-wave infrared continuous zoom lens described in Fig. 9 Aberration Analysis figure when short burnt state, and Figure 10 is that point range figure, Figure 11 are that MTF figure, Figure 12 are curvature of field distortion figure;

From figure, can find, the various aberrations of each burnt section have obtained good correction, and disc of confusion is all corrected to and approaches Ai Liban size, and MTF approaches diffraction limit, distortion <5%.

As can be seen here, the utility model long-focus long-wave infrared continuous zoom lens has good image quality.

Finally it should be noted that: above embodiment is only in order to illustrate the utility model and the described technical scheme of unrestricted the utility model.Therefore, although this instructions has been described in detail the utility model with reference to the above embodiments,, those of ordinary skill in the art should be appreciated that still and can modify or be equal to replacement the utility model; And all do not depart from technical scheme and the improvement thereof of spirit and scope of the present utility model, it all should be encompassed in the middle of claim scope of the present utility model.

Claims (6)

1. a long-focus long-wave infrared continuous zoom lens, is characterized in that: by object space, to image space, comprised successively front fixedly group, zoom group, compensation group, rear fixedly group, focusing group and explorer portion;

Described front fixedly group has positive light coke, is the falcate germanium single crystal positive lens of a slice convex surface towards object space, and surface type is sphere;

Described zoom group has negative power, is a slice double concave germanium single crystal negative lens, and its side towards image space is aspheric surface, total shift motion 57.98mm of described lens;

Described compensation group has positive light coke, is the lenticular germanium single crystal positive lens of a slice, and its side towards object space is aspheric surface, total shift motion 33.54mm of described lens;

Described rear fixedly group has negative power, is the falcate germanium single crystal positive lens of a slice convex surface towards image space, and its convex surface is diffraction surfaces;

Described focusing group has positive light coke, is the falcate germanium single crystal positive lens of a slice convex surface towards object space, and its convex surface is aspheric surface, total shift motion 4.5mm of described lens;

After described focusing group, be long wave uncooled detector part, comprise protecting window and image planes; Aperture diaphragm, in compensation group and rear fixedly between group, keeps constant in zoom process.

2. long-focus long-wave infrared continuous zoom lens according to claim 1, is characterized in that, described camera lens meets following parameter:

Effective focal length EFL=40～the 160mm of described camera lens, F number=1.0, optical system overall length=310mm, adaptive detector resolution 640 * 480, Pixel size 25 μ m.

3. long-focus long-wave infrared continuous zoom lens according to claim 1, is characterized in that, the average MTF>0.5@20lp/mm of the full visual field of described camera lens.

4. long-focus long-wave infrared continuous zoom lens according to claim 1, is characterized in that, the aspheric surface in the eyeglass of described camera lens meets following expression formula:

Wherein z is aspheric surface along optical axis direction when highly for the position of r, apart from the distance rise on aspheric surface summit, and the vertex curvature of c presentation surface, k is circular cone coefficient, α ₂, α ₃, α ₄, α 5, α ₆for high order aspheric surface coefficient.

5. long-focus long-wave infrared continuous zoom lens according to claim 1, is characterized in that, the diffraction surfaces in the eyeglass of described camera lens meets following expression formula:

Φ＝A ₁ρ ²+A ₂ρ ⁴

The position phase that wherein Φ is diffraction surfaces, ρ=r/r _n, r _nthe planning radius of diffraction surfaces, A ₁, A ₂phase coefficient for diffraction surfaces.

6. long-focus long-wave infrared continuous zoom lens according to claim 1, is characterized in that, the horizontal field of view angular region of described camera lens is: 2w=35.5 °～1.8 °