CN105589178B - High-low temperature confocal and stray light-free optical system - Google Patents

Abstract

The invention discloses a high-low temperature confocal and stray light-free optical system, which is sequentially provided with the following components from an object side to an image side: the first lens (1), the said first lens (1) is the spherical lens of glass with negative focal length; the second lens (2), the said second lens (2) is a plastic aspheric lens with negative focal length; a third lens (3), wherein the third lens (3) is a plastic aspheric lens with a positive focal length; a diaphragm (100); the fourth lens (4), the said fourth lens (4) is the spherical lens of glass with positive focal length; a fifth lens (5), wherein the fifth lens (5) is a plastic aspheric lens with a negative focal length; a sixth lens (6), wherein the sixth lens (6) is a plastic aspheric lens with a positive focal length; a photosensitive chip (200). The invention has simple structure, high and low temperature confocal, high pixel, small distortion, high transmittance, wear resistance and no stray light.

Description

A high and low temperature confocal, stray light free optical system

【Technical field】

The invention relates to an optical system, more specifically a high-low temperature confocal and stray-free optical system.

【Background technique】

At present, the lenses used in monitoring and vehicle lenses generally have such shortcomings: the high and low temperature of the lens is not confocal; the distortion of the ultra-wide-angle lens is large; the transmittance of the image plane is not enough, there is color cast; The lens improves certain aspects at the expense of other aspects. For example, in order to achieve high and low temperature confocal and high pixels, more lenses are used, and even lanthanum series glass is used to make the image surface have color cast, stray light and ghosting. In some cases, it cannot meet consumers' requirements for bright and refreshing image quality, or the distortion of the ultra-wide-angle lens has not been corrected at all, and there is a defect of large distortion.

Therefore, the present invention just produces based on above deficiency.

【Content of invention】

The purpose of the present invention is to overcome the deficiencies of the prior art and provide an optical system with simple structure, high and low temperature confocal, high pixel, small distortion, high transparency, wear resistance, no stray light and super wide angle.

The present invention is achieved through the following technical solutions:

A high and low temperature confocal, stray light-free optical system, characterized in that: from the object side to the image side, there are:

The first lens 1, the first lens 1 is a glass spherical lens with a negative focal length;

The second lens 2, the second lens 2 is a plastic aspheric lens with a negative focal length;

The third lens 3, the third lens 3 is a plastic aspheric lens with a positive focal length;

Aperture 100;

The fourth lens 4, the fourth lens 4 is a glass spherical lens with a positive focal length;

The fifth lens 5, the fifth lens 5 is a plastic aspheric lens with a negative focal length;

The sixth lens 6, the sixth lens 6 is a plastic aspheric lens with a positive focal length;

Photosensitive chip 200.

The above-mentioned high and low temperature confocal, stray light free optical system is characterized in that a protective glass 300 is provided between the sixth lens 6 and the photosensitive chip 200 .

The above-mentioned high and low temperature confocal, stray light free optical system is characterized in that: the first lens 1, the second lens 2 and the third lens 3 are meniscus lenses, and the fourth lens 4 and The sixth lens 6 is a biconvex lens, and the fifth lens 5 is a biconcave lens.

The above-mentioned high and low temperature confocal, stray light free optical system is characterized in that: the aspheric surface shapes of the second lens 2, the third lens 3, the fifth lens 5 and the sixth lens 6 satisfy the following equation:

In the formula, the parameter c is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, and k is the coefficient of the conic conic curve; when the k coefficient is less than -1, the surface curve of the lens is double curve, when the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse, when the k coefficient is equal to 0, the lens surface curve The curve is circular, and when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the aspheric coefficients respectively.

Compared with prior art, the present invention has following advantage:

1. The present invention uses a small amount of plastic aspheric lenses plus lower-priced glass spherical lenses, and at the same time focuses on the elimination of stray light and ghost images during design, so that the lens transmittance is greatly increased, and stray light and ghost images are completely eliminated. Eliminate and solve the shortcomings of the existing ultra-wide-angle lenses that generally use multiple spherical glass lenses, resulting in low transmittance, color cast, serious stray light and ghosting.

2. The present invention corrects the distortion so that the entire picture can be imaged clearly, and solves the disadvantage of the existing ultra-wide-angle high-pixel lens due to large peripheral distortion and picture accumulation, which leads to the inability to reflect the peripheral resolution.

3. The high and low temperature focus overlap of the present invention realizes the consistency of image quality in different environments, and solves the problem that the existing high-pixel surveillance lens cannot achieve confocal at high and low temperature, or can focus well at normal temperature (20°C) when white light is generated Finally, under the high and low temperature environment, there will be severe focus misalignment and image blurring.

4. The structure of the present invention is simple, and the performance of the produced lens is excellent, which is suitable for popularization and application.

【Description of drawings】

Figure 1 is a schematic diagram of the present invention.

【Detailed ways】

The present invention will be further described below in conjunction with accompanying drawing:

A high and low temperature confocal, stray light-free optical system, which is sequentially equipped from the object side to the image side:

The first lens 1, the first lens 1 is a glass spherical lens with a negative focal length;

The second lens 2, the second lens 2 is a plastic aspheric lens with a negative focal length;

The third lens 3, the third lens 3 is a plastic aspheric lens with a positive focal length;

Aperture 100;

The fourth lens 4, the fourth lens 4 is a glass spherical lens with a positive focal length;

The fifth lens 5, the fifth lens 5 is a plastic aspheric lens with a negative focal length;

The sixth lens 6, the sixth lens 6 is a plastic aspheric lens with a positive focal length;

Photosensitive chip 200.

The second lens 2, the third lens 3, the fifth lens 5 and the sixth lens 6 are plastic aspheric lenses, the first lens 1 and the fourth lens 4 are glass spherical lenses, and the corresponding expansion of different materials The coefficients are different, and different surface shapes are designed to make the surface shapes complementary at high and low temperatures, so that the image quality of the lens remains unchanged at high and low temperatures. The present invention adopts 4 pieces of plastic lenses and 2 pieces of glass lenses, the number of lenses is small, and different lens materials are reasonably matched. Under the premise of ensuring the image quality of the lens, the use of as few lenses as possible can improve the overall transmittance and increase the lens transmittance. Dramatically increased, stray light and ghosting are completely eliminated. The present invention adopts reasonable material matching of plastic lenses and glass lenses, and according to the positive and negative focal lengths of each lens, can rationally distribute the refractive index Nd and the Abbe number Vd value, so that the corresponding lens can be selected according to different refractive indices and Abbe numbers. Specific materials; in addition, the spectral design matching the photosensitive chip 200 is adopted, thereby ensuring the consistency of the image quality, color and chip, and realizing the uniformity of the entire picture.

A protective glass 300 is provided between the sixth lens 6 and the photosensitive chip 200 .

The first lens 1, the second lens 2 and the third lens 3 are meniscus lenses, the fourth lens 4 and the sixth lens 6 are biconvex lenses, and the fifth lens 5 is a biconcave lens, Thereby each eyeglass is brought into play to the maximum effect, thereby the distortion of the present invention is very little. Moreover, the specific shape of each lens also takes into account the level that the current technology can achieve, and achieves a reasonable structural layout.

The aspherical surface shapes of the second lens 2, the third lens 3, the fifth lens 5 and the sixth lens 6 satisfy the following equation:

In the formula, the parameter c is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, and k is the coefficient of the conic conic curve; when the k coefficient is less than -1, the surface curve of the lens is double curve, when the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse, when the k coefficient is equal to 0, the lens surface curve The curve is circular, and when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the aspheric coefficients respectively.

Below is the actual design case of the present invention:

where R corresponds to the formula The reciprocal of c, that is, c=1/R.

Aspheric coefficients for each aspheric surface:

k alpha ₂ alpha ₃ alpha ₄ alpha ₅ S3 3.212 3.5E-003 -2.1E-004 2.3E-006 8.3E-008 S4 -2.31 0.0161 9.8E-005 -5.213E-005 -1.898E-006 S5 0.15 -6.1E-004 3.89E-004 -2.3E-005 -9.8E-008 S6 -56.32 1.1E-002 6.5E-004 -5.82E-004 2.376E-004 S9 0.85 3.75E-003 -4.1E-004 -3.5E-004 2.3E-004 S10 -120 0.0016 7.31E-004 -5.33E-005 -6.32E-005 S11 -26 4.5E-003 -1.233E-004 3.02E-005 1.35E-006 S12 -3.212 -5.73E-003 2.9E-004 5.62E-005 -8.5E-006

Claims (3)

1. a kind of high/low temperature is confocal, without veiling glare optical system, it is characterised in that：It is equipped with successively from object side to image side：

First lens (1), first lens (1) are that focal length is negative glass spherical lens；

Second lens (2), second lens (2) are that focal length is negative plastic aspheric lens；

3rd lens (3), the 3rd lens (3) are that focal length is positive plastic aspheric lens；

Diaphragm (100)；

4th lens (4), the 4th lens (4) are that focal length is positive glass spherical lens；

5th lens (5), the 5th lens (5) are that focal length is negative plastic aspheric lens；

6th lens (6), the 6th lens (6) are that focal length is positive plastic aspheric lens；

Sensitive chip (200)；First lens (1), the second lens (2) and the 3rd lens (3) are meniscus shaped lens, described The 4th lens (4) and the 6th lens (6) be biconvex lens, the 5th lens (5) be biconcave lens；

First lens towards the surface (S1) of object side radius of curvature for 29.24, towards image side surface (S2) song Rate radius is 5.68, and the effective diameter on first lens (1) towards the surface (S1) of object side is the 15.2, table towards image side The effective diameter in face (S2) is 10.2, and the thickness of first lens (1) is 0.7；

The radius of curvature on second lens (2) towards the surface (S3) of object side is 12.4, the surface (S4) towards image side Radius of curvature is 2.33, second lens (2) towards the surface (S3) of object side effective diameter for 9.96, towards image side The effective diameter on surface (S4) is 6.9, and the spacing of second lens (2) and the first lens (1) is 1.8, described second The thickness of lens (2) is 1.33；

The radius of curvature on surface (S5) of the 3rd lens (3) towards object side for 4.6, towards image side surface (S6) song Rate radius is 9.6, and the effective diameter on surface (S5) of the 3rd lens (3) towards object side is the 6.7, surface towards image side (S6) effective diameter is 3.76, and the spacing of the 3rd lens (3) and the second lens (2) is 2.23, and the described the 3rd thoroughly The thickness of mirror (3) is 4.297；

The spacing of the diaphragm (100) and the 3rd lens (3) is 1.048, and the effective diameter of the diaphragm (100) is 2.73；

The radius of curvature on surface (S7) of the 4th lens (4) towards object side is 10.055, the surface (S8) towards image side Radius of curvature for -3.997, the effective diameter on surface (S7) of the 4th lens (4) towards object side is 6.86, towards picture The effective diameter on the surface (S8) of side is 6.86, and the spacing of the 4th lens (4) and diaphragm (100) is 0.029, described The thickness of 4th lens (4) is 3.62；

The radius of curvature on surface (S9) of the 5th lens (5) towards object side for -4, towards image side surface (S10) song Rate radius is 11, and the effective diameter on surface (S9) of the 5th lens (5) towards object side is the 3.51, surface towards image side (S10) effective diameter is 4.275, and the spacing of the 5th lens (5) and the 4th lens (4) is the 0.104, the described the 5th The thickness of lens (5) is 0.4；

The radius of curvature on surface (S11) of the 6th lens (6) towards object side is 5.4, the surface (S12) towards image side Radius of curvature is -4, and the effective diameter on surface (S11) of the 6th lens (6) towards object side is 5.27, towards image side The effective diameter on surface (S12) is 5.54, and the spacing of the 6th lens (6) and the 5th lens (5) is 0.13346, described The 6th lens (6) thickness be 2.51.

2. high/low temperature according to claim 1 is confocal, without veiling glare optical system, it is characterised in that：6th lens (6) protective glass (300) is equipped between sensitive chip (200).

3. high/low temperature according to claim 1 is confocal, without veiling glare optical system, it is characterised in that：Second lens (2), the aspherical surface shape of the 3rd lens (3), the 5th lens (5) and the 6th lens (6) meets below equation： In formula, parameter c is Curvature corresponding to radius, y are radial coordinate, and unit is identical with length of lens unit, and k is circular cone whose conic coefficient；Work as k When coefficient is less than -1, the face shape curve of lens is hyperbola, and when k-factor is equal to -1, the face shape curve of lens is parabola；When When k-factor is between -1 to 0, the face shape curve of lens is ellipse, and when k-factor is equal to 0, the face shape curve of lens is circle Shape, when k-factor is more than 0, the face shape curve of lens is oblateness；α₁To α₈Asphericity coefficient is represented respectively.