Thermal stability electronic rearview mirror optical imaging system

Abstract

The utility model discloses a thermally stable electronic rearview mirror optical imaging system which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an optical filter, protective glass and an image plane from an object plane to an image plane along an optical axis. The object plane side of the first lens is a convex surface, and the image plane side is a concave surface. The object surface side of the second lens is a convex surface, and the image surface side is a convex surface; the object plane side of the third lens is a concave surface, and the image plane side is a concave surface; the object plane side of the fourth lens is a convex surface, and the image plane side is a convex surface; the object plane side of the fifth lens is a concave surface, and the image plane side is a convex surface; the object plane side of the sixth lens is a convex surface, and the image plane side is a convex surface; the object plane side of the seventh lens is a concave surface, and the image plane side is a convex surface; wherein the sixth lens and the seventh lens form a group of glued lenses. The thermally stable electronic rearview mirror optical imaging system has the characteristics of high illumination, large target surface, aberration optimization, purple edge optimization and stable thermal drift.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical imaging system and vehicle mounted imaging device technical field, concretely, it is a kind of thermal stability electronic rearview mirror optical imaging system. BACKGROUND

[0002] Electronic rearview mirror is a product combination based on camera and display, which can enhance the visual perception of the driver to the surrounding and side rear of the vehicle, further enhance driving safety and comfort. Among them, the image collected by the external camera is displayed on the display screen in the cabin after data processing, and can also integrate functions such as blind area warning and obstacle prompt.

[0003] Electronic rearview mirror is called "real thinking rearview mirror" in the industry, which is small in size, retractable, low in wind resistance, more scientific and technological, and can avoid the driver to change the viewing angle greatly during driving, so as to know the surrounding road conditions. Compared with traditional optical rearview mirror, electronic rearview mirror has obvious advantages, but most of the lenses of the current electronic rearview mirror have the problems of small matching target surface, low edge illumination, serious aberration and purple edge, and large temperature drift when working in high and low temperature environment. CONTENT OF THE UTILITY MODEL

[0004] The utility model provides a kind of thermal stability electronic rearview mirror optical imaging system, the thermal stability electronic rearview mirror optical imaging system has the characteristics of high illumination, large target surface, aberration optimization, purple edge optimization, temperature drift stability when working in high and low temperature.

[0005] The above technical purpose of the utility model is realized by the following technical scheme: a kind of thermal stability electronic rearview mirror optical imaging system, including successively along optical axis from object plane to image plane: first lens, second lens, third lens, fourth lens, diaphragm, fifth lens, sixth lens, seventh lens, optical filter, protective glass and image plane;

[0006] The object plane side of first lens is convex, and the image plane side is concave;

[0007] The object plane side of second lens is convex, and the image plane side is convex;

[0008] The object plane side of third lens is concave, and the image plane side is concave;

[0009] The object plane side of fourth lens is convex, and the image plane side is convex;

[0010] The object plane side of fifth lens is concave, and the image plane side is convex;

[0011] The object plane side of sixth lens is convex, and the image plane side is convex;

[0012] The object plane side of seventh lens is concave, and the image plane side is convex;

[0013] The sixth lens and the seventh lens constitute a cemented lens;

[0014] and satisfy the following relationship:

[0015] 0.8<|f1 / f|<1.3; 1.3<|f2 / f|<1.8; 0.9<|f3 / f|<1.4; 0.9<|f4 / f|<1.4; 2.2<|f5 / f|<2.8; 4.6<|f6 / f|<5.1; 9.3<|f7 / f|<9.8;

[0016] wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the effective focal length of the whole optical imaging system.

[0017] Further, the Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, the Abbe number Vd3 of the third lens, the Abbe number Vd4 of the fourth lens and the Abbe number Vd5 of the fifth lens are all greater than 31 and less than 43; the Abbe number Vd6 of the sixth lens is greater than 69 and less than 73; and the Abbe number Vd7 of the seventh lens is greater than 20 and less than 25.

[0018] Further, the relative illumination of the optical imaging system satisfies the following condition:

[0019] RI≥65%.

[0020] Further, the maximum total image height of the optical imaging system satisfies the following condition:

[0021] IHmax≥7.688mm.

[0022] Further, the optical imaging system satisfies the following condition:

[0023] 2

[0024] wherein L represents the total length of the optical imaging system, and IHmax represents the maximum total image height of the optical imaging system.

[0025] Further, the first lens is of a concave-convex type, with a convex surface on the object side and a concave surface on the image side, and has a negative optical power;

[0026] the second lens is of a biconvex type, with a large convex surface on the object side and a small convex surface on the image side, and has a positive optical power;

[0027] the third lens is of a biconcave type, with a concave surface on the object side and a concave surface with a platform on the image side, and has a negative optical power;

[0028] The fourth lens is biconvex, and the object plane side is a convex surface with a platform, and the image plane side is a convex surface, and the optical power is positive;

[0029] The fifth lens is meniscus, and the object plane side is a concave surface, and the image plane side is a convex surface, and the optical power is positive;

[0030] The sixth lens is biconvex, and the object plane side is a small convex surface, and the image plane side is a large convex surface, and the optical power is negative;

[0031] The seventh lens is meniscus, and the object plane side is a concave surface, and the image plane side is a convex surface, and the optical power is negative;

[0032] Further, when the working distance is infinite, the total focal length of the optical imaging system is f=5.28mm, FNO=2.0, and the maximum full image height is 7.688mm.

[0033] In summary, the utility model has the following beneficial effects:

[0034] High illuminance: relative illuminance RI≥65%, clear imaging under cloudy and low brightness conditions at night.

[0035] Large target surface: IHmax≥7.688mm, the larger the target surface, the larger the chip size that can be matched, the more chip types that can be selected, and the market diversity demand is met.

[0036] Aberration and edge optimization purple edge: the lens group is internally structured by reasonable optical power matching and multiple spherical lens surface curves, so that the imaging aberration and edge chromatic aberration are reduced, especially the purple edge phenomenon, which is conducive to the display of the electronic rearview mirror image and can better provide the driver with a peripheral view.

[0037] Thermal drift stability: when the outside temperature changes greatly, stable imaging performance can still be maintained, and the imaging quality will not decrease due to temperature changes. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 An optical imaging system schematic diagram provided by the utility model embodiment is shown in the figure;

[0039] Figure 2 An MTF analysis diagram provided by the utility model embodiment is shown in the figure;

[0040] Figure 3 A defocus curve diagram of the optical imaging system provided by the utility model embodiment at 20 DEG C is shown in the figure;

[0041] Figure 4 A defocus curve diagram of the optical imaging system provided by the utility model embodiment at -40 DEG C is shown in the figure;

[0042] Figure 5The optical imaging system provided by the embodiment of the present application provides a defocus curve graph at 85 DEG C.

[0043] Figure 6 The optical imaging system provided by the embodiment of the present application provides a field curvature graph.

[0044] Figure 7 The optical imaging system provided by the embodiment of the present application provides a relative luminance graph.

[0045] Figure 8 The optical imaging system provided by the embodiment of the present application provides a standard point column graph. DETAILED DESCRIPTION

[0046] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0047] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0048] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0049] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] As Figure 1As shown, the embodiment provides a thermal stable electronic rearview mirror optical imaging system, which sequentially comprises, along the optical axis from the object plane to the image plane: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a diaphragm STO, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter IR, a protective glass CG and an image plane IMA;

[0051] The object plane side S1 of the first lens E1 is a convex surface, and the image plane side S2 is a concave surface;

[0052] The object plane side S3 of the second lens E2 is a convex surface, and the image plane side S4 is a convex surface;

[0053] The object plane side S5 of the third lens E3 is a concave surface, and the image plane side S6 is a concave surface;

[0054] The object plane side S7 of the fourth lens E4 is a convex surface, and the image plane side S8 is a convex surface;

[0055] The object plane side S10 of the fifth lens E5 is a concave surface, and the image plane side S11 is a convex surface;

[0056] The object plane side S12 of the sixth lens E6 is a convex surface, and the image plane side S13 is a convex surface;

[0057] The object plane side S13 of the seventh lens E7 is a concave surface, and the image plane side S14 is a convex surface;

[0058] The sixth lens E6 and the seventh lens E7 constitute a set of cemented lenses;

[0059] And the following relationship is satisfied:

[0060] 0.8<|f1 / f|<1.3; 1.3<|f2 / f|<1.8; 0.9<|f3 / f|<1.4; 0.9<|f4 / f|<1.4; 2.2<|f5 / f|<2.8; 4.6<|f6 / f|<5.1; 9.3<|f7 / f|<9.8;

[0061] Wherein, f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f7 is the focal length of the seventh lens E7, and f is the effective focal length of the whole optical imaging system.

[0062] Preferably, the Abbe number Vd1 of the first lens E1, the Abbe number Vd2 of the second lens E2, the Abbe number Vd3 of the third lens E3, the Abbe number Vd4 of the fourth lens E4 and the Abbe number Vd5 of the fifth lens E5 are all greater than 31 and less than 43; the Abbe number Vd6 of the sixth lens E6 is greater than 69 and less than 73; and the Abbe number Vd7 of the seventh lens E7 is greater than 20 and less than 25.

[0063] Preferably, the relative illumination of the optical imaging system satisfies the following condition:

[0064] RI≥65%.

[0065] Preferably, the maximum total image height of the optical imaging system satisfies the following condition:

[0066] IHmax≥7.688mm.

[0067] Preferably, the optical imaging system satisfies the following condition:

[0068] 2

[0069] wherein L represents the total length of the optical imaging system, and IHmax represents the maximum total image height of the optical imaging system.

[0070] Preferably, the first lens E1 is of meniscus type, and the object side S1 is a convex surface, the image side S2 is a concave surface, and the optical power is negative;

[0071] the second lens E2 is of biconvex type, and the object side S3 is a large convex surface, the image side S4 is a small convex surface, and the optical power is positive;

[0072] the third lens E3 is of biconcave type, and the object side S5 is a concave surface, the image side S6 is a concave surface with a platform, and the optical power is negative;

[0073] the fourth lens E4 is of biconvex type, and the object side S7 is a convex surface with a platform, the image side S8 is a convex surface, and the optical power is positive;

[0074] the fifth lens E5 is of meniscus type, and the object side S10 is a concave surface, the image side S11 is a convex surface, and the optical power is positive;

[0075] the sixth lens E6 is of biconvex type, and the object side S12 is a small convex surface, the image side S13 is a large convex surface, and the optical power is negative;

[0076] the seventh lens E7 is of meniscus type, and the object side S13 is a concave surface, the image side S14 is a convex surface, and the optical power is negative;

[0077] Preferably, the stop ST0 is arranged between the fourth lens E4 and the fifth lens E5.

[0078] In the patent embodiment, when the working distance is infinity, the total focal length of the optical imaging system is f=5.28mm, the FNO is 2.0, and the maximum total image height is 7.688mm.

[0079] The embodiment is only an explanation of the utility model, and is not a limitation of the utility model, and a person skilled in the art can make modifications without creative contribution according to the needs after reading the specification, but as long as it is within the scope of the claims of the utility model, it is protected by the patent law.

[0080] In the embodiment, the parameters of each lens are listed in Table 1 in turn.

[0081] Table 1 Physical parameters of each lens

[0082]

[0083] It should be noted that Surf in Table 1 represents the mirror number, Radius represents the curvature radius, Thickness represents the thickness, Index represents the refractive index, ABB represents the Abbe coefficient, EFL-E represents the lens focal length, INFINITY represents infinity, the positive curvature radius represents that the mirror is curved towards the object plane, and the negative curvature radius represents that the mirror is curved towards the image plane. The mirror numbers 1 and 2 represent two mirrors of the first lens E1 along the light incident direction in turn, the mirror numbers 3 and 4 represent two mirrors of the second lens E2 along the light incident direction in turn, the mirror numbers 5 and 6 represent two mirrors of the third lens E3 along the light incident direction in turn, the mirror numbers 7 and 8 represent two mirrors of the fourth lens E4 along the light incident direction in turn, the mirror numbers 10 and 11 represent two mirrors of the fifth lens E5 along the light incident direction in turn, the mirror number 12 represents the mirror of the sixth lens E6 towards the object side, the mirror number 13 represents the cemented surface of the sixth lens E6 and the seventh lens E7, and the mirror number 14 represents the mirror of the seventh lens E7 towards the image side.

[0084] In the embodiment of the utility model, Figure 2 is represented as a modulation transfer function (MTF) curve diagram of a visible light band, which represents the comprehensive resolution capability of an optical imaging system, in the diagram, the horizontal axis represents the spatial frequency, the unit is cycles per millimeter (cycles / mm), and the vertical axis represents the value of the modulation transfer function (MTF). The value of MTF is used to evaluate the imaging quality of the lens, and the value range is 0-1. It is particularly pointed out that the optical transfer function is a more accurate, intuitive and common way to evaluate the imaging quality of an optical imaging system. The higher and smoother the curve is, the better the imaging quality of the system is, and the stronger the restoration ability of the real image is. From Figure 2 It can be seen that the imaging area MTF of the center is greater than 0.6 when the spatial frequency of the visible light band is 100 lp / mm, and the imaging quality is good. Figure 3 is represented as a defocus curve diagram of the visible light band at 20 DEG C, from Figure 3It can be seen that the MTF of the lens is good, the focusing is convenient, and the defocus curve trends are consistent under different field angles; from Figure 4 and Figure 5 It can be seen that the defocus curves at low temperature-40℃ and high temperature 85℃ meet high resolution, the defocus curve focal point changes little, and the thermal drift effect is stable; Figure 6 The field curvature is represented by a field curvature graph, which is Figure 6 It can be seen that the field curvature value is controlled between-0.05mm and 0.05mm, and the smaller the field curvature value, the better the imaging quality of the lens; Figure 7 The relative luminance graph is represented by a relative luminance graph, which is Figure 7 It can be seen that the relative luminance of the maximum edge field is greater than 65%, the edge luminance is high, and clear imaging can still be achieved under the conditions of overcast, night and low brightness; Figure 8 The standard point column graph of the lens is shown.

Claims

1. A thermally stabilized electronic rearview mirror optical imaging system, characterized in that: Along the optical axis from the object plane to the image plane, the following components are included in sequence: first lens, second lens, third lens, fourth lens, aperture stop, fifth lens, sixth lens, seventh lens, filter, protective glass, and image plane; The first lens has a convex surface on the object side and a concave surface on the image side; The second lens has a convex surface on both the object plane and the image plane sides; The object plane side of the third lens is concave, and the image plane side is also concave. The fourth lens has a convex surface on both the object plane and the image plane sides; The fifth lens has a concave surface on the object plane side and a convex surface on the image plane side; The object plane side of the sixth lens is convex, and the image plane side is also convex. The seventh lens has a concave surface on the object plane side and a convex surface on the image plane side; The sixth and seventh lenses form a set of cemented lenses; And it satisfies the following relationship: 0.8<|f1 / f|<1.3; 1.3<|f2 / f|<1.8; 0.9<|f3 / f|<1.4; 0.9<|f4 / f|<1.4; 2.2<|f5 / f|<2.8; 4.6<|f6 / f|<5.1; 9.3<|f7 / f|<9.8; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the effective focal length of the entire optical imaging system.

2. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: The Abbe constants Vd1, Vd2, Vd3, Vd4, and Vd5 of the first lens are all greater than 31 and less than 43; the Abbe constant Vd6 of the sixth lens is greater than 69 and less than 73; and the Abbe constant Vd7 of the seventh lens is greater than 20 and less than 25.

3. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: The relative illumination of an optical imaging system satisfies the following condition: RI ≥ 65%.

4. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: The maximum holoimage height of an optical imaging system satisfies the following condition: IHmax≥7.688mm.

5. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: An optical imaging system must meet the following conditions: 2 < L / IHmax < 3 Where L represents the total length of the optical imaging system, and IHmax represents the maximum holoimage height.

6. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: The first lens is concave-convex, with the object side being convex and the image side being concave, and its optical power is negative. The second lens is biconvex, with a large convex surface on the object side and a small convex surface on the image side, and its optical power is positive. The third lens is biconcave, with a concave surface on the object side and a concave surface with a plateau on the image side, and its optical power is negative. The fourth lens is biconvex, with a convex surface on the object side and a convex surface on the image side, and its optical power is positive. The fifth lens is concave-convex, with the object side being concave and the image side being convex, and its optical power is positive. The sixth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is negative. The seventh lens is concave-convex, with the object side being concave and the image side being convex, and its optical power is negative.

7. The thermally stabilized electronic rearview mirror optical imaging system according to claim 1, characterized in that: When the working distance is infinite, the total focal length of the optical imaging system is f=5.28mm, FNO=2.0, and the maximum holographic height is 7.688mm.

Images