KR20080043693A - Wide-angle lens and optical system having the same - Google Patents

Abstract

A wide-angle lens and an optical system having the same are provided to detect a motion of an object around a sensor accurately by increasing light intensity around the sensor. An optical system includes a wide-angle lens(L). An object-side surface(2) of the wide-angle lens is convex toward an object. An image-side surface(3) of the wide-angle lens is convex toward an image on an optical axis. A refractive surface of at least one of the object-side and image-side surfaces is formed in an aspherical shape. The object-side surface of the wide-angle lens is arranged behind an aperture shutter(AS). The image-side surface of the wide-angle lens is arranged in front of an image forming surface(IP). A relation, 1.0 < TL/f < 3.5, is satisfied, where the TL is a distance from the aperture shutter to the image forming surface and the f is a focal distance of the optical system.

Description

Wide-angle lens and optical system having the same {Wide-angle lens And Optical System Having The Same}

The present invention relates to an optical system having a wide angle of view and to a miniaturization thereof, and more particularly, to a variety of surveillance devices, such as those mounted on a camera module of a small device such as a mobile communication terminal or a PDA, or for door monitoring or vehicle rear monitoring. The present invention relates to an optical system having a wide-angle lens and a wide-angle lens provided therein, which can implement an optical system for imaging that can be used in a camera or the like, or an optical system for sensing a motion of a subject.

The optical system for imaging mounted on a camera module of a small device such as a mobile communication terminal or a PDA, or used for various surveillance cameras such as door monitoring and vehicle rear monitoring is preferably small and has a wide photographing range at a short range.

In many cases, a combination of a plurality of lenses has been used to meet such demands, but this has been a cause of high cost and a difficulty in miniaturizing the optical system.

In addition, there have been attempts to use only one lens, but there are problems in that various aberration performances such as a small angle of view, distortion, spherical aberration, and the like are deteriorated.

Therefore, there has been a demand for an optical system for imaging that can realize a high angle of view while using only one lens, improve aberration performance, and secure an appropriate resolution.

Such a request is required not only for the optical system for imaging but also for the optical system for sensing for detecting the movement of an object (subject).

1 is a schematic diagram showing the principle of a conventional optical pointing device used for detecting a movement of a subject.

As shown in FIG. 1, a conventional optical pointing device is generally made of an LED or the like, and includes a light source unit 11 for irradiating light and light reflected from the subject 12 by light emitted from the light source unit 11. The lens unit 13 for condensing the light and the optical sensor 14 for detecting the movement of the subject 12 by detecting the image collected by the lens unit 13.

In the case of a general optical mouse, the subject 12 is formed of a pad corresponding to the ground or the ground. In the mouse, as the user moves the mouse, the relative movement of the subject (ground) is detected by the optical sensor 14. The pointing (positioning) operation is performed.

Recently, there is an attempt to apply such an optical pointing device to a mobile device such as a mobile communication terminal. Korean Patent Publication No. 534397 discloses a technique of applying an optical pointing device to a mobile communication terminal.

As such, the optical pointing device applied to the mobile communication terminal uses the surface of the finger as a subject, and detects the movement of the finger through the optical sensor 14 to perform the pointing operation.

However, in order to apply an optical pointing device to a mobile device such as a mobile communication terminal, the size of the optical system for sensing should be small, the amount of peripheral light can be secured, the distortion must be small, and the view angle should be limited.

Accordingly, there is a need for an optical system that can overcome at least some of the problems described above.

An object of the present invention is to provide a wide-angle lens capable of miniaturization, a wide angle of view and an appropriate resolution, and an optical system having the same.

In addition, an object of the present invention is to provide a wide-angle lens that can ensure a sufficient amount of ambient light, and can be implemented at a low cost and an optical system having the same.

As one aspect for achieving the above object, the present invention, the object side surface has a convex shape toward the object side, the upper surface has a convex shape from the upper side on the optical axis, at least one refractive surface of the object side surface and the upper surface is an aspherical surface Wide-angle lens consisting of; It includes, and provides an optical system having a wide-angle lens including only one of the wide-angle lens as a refractive lens.

Preferably, the image side surface of the wide-angle lens may have a concave or convex shape from the peripheral portion to the image side.

More preferably, when the object-side surface of the wide-angle lens is disposed behind the aperture stop and the image-side surface of the wide-angle lens is disposed in front of the imaging surface, the following conditional expression 1 Can be satisfied.

Conditional Expression 1 1.0 <TL / f <3.5

TL: distance from the aperture stop to the image plane

        f: focal length of optical system

Also preferably, when the object-side surface of the wide-angle lens is disposed behind the aperture stop and the image-side surface of the wide-angle lens is disposed in front of the image forming surface, the following conditional expression 2 is satisfied for the diagonal angle of view. Can be.

Conditional Expression 2 # 30 <FOV / TL <150

Where: FOV: Diagonal Angle of View

        TL: distance from the aperture stop to the image plane

Also preferably, the following Conditional Expression 3 may be satisfied with respect to the refractive index of the wide-angle lens.

조건 1.49 <N <1.67

Where N is the refractive index of the wide-angle lens

The wide angle lens collects light reflected from a subject to form an image on a sensor, and the subject may reflect light emitted from a light source unit.

In this case, when the object-side surface of the wide-angle lens is disposed behind the aperture stop, and the image-side surface of the wide-angle lens is disposed in front of the image forming surface, the following Conditional Expression 3 is given with respect to the refractive index of the wide-angle lens. The following conditional expression 4 may be satisfied with respect to the dimension of the optical axis direction, or the following conditional expression 5 may be satisfied with respect to the diagonal angle of view.

조건 1.49 <N <1.67

Conditional Expression 4 2.5 <TL / f <3.5

[Condition 5] # 80 <FOV / TL <150

Where N is the refractive index of the wide-angle lens

        TL: distance from the aperture stop to the image plane

        f: focal length of optical system

        FOV: Diagonal Angle of View

As another aspect, the present invention provides an object side surface having a convex shape on the object side, and an upper surface having a convex shape on the optical axis, wherein at least one of the refractive surface of the object side surface and the upper surface is an aspherical surface. A wide-angle lens is provided.

Preferably, the image side surface of the wide-angle lens may have a concave or convex shape from the peripheral portion to the image side.

More preferably, when the object-side surface of the wide-angle lens is disposed behind the aperture stop and the image-side surface of the wide-angle lens is disposed in front of the imaging surface, the following conditional expression 1 Alternatively, the following Conditional Expression 4 may be satisfied, the following Conditional Expression 2 or the following Conditional Expression 5 may be satisfied with respect to the diagonal angle of view, or the following Conditional Expression 3 may be satisfied with respect to the refractive index of the wide-angle lens.

Conditional Expression 1 1.0 <TL / f <3.5

Conditional Expression 2 # 30 <FOV / TL <150

조건 1.49 <N <1.67

Conditional Expression 4 2.5 <TL / f <3.5

[Condition 5] # 80 <FOV / TL <150

TL: distance from the aperture stop to the image plane

        f: focal length of optical system

        FOV: Diagonal Angle of View

        N: refractive index of wide angle lens

According to the present invention, since the optical system can be miniaturized and thinned, has a relatively wide angle of view, has a low distortion, and has an appropriate resolution to represent an image, it is mounted on a camera module of a small device such as a mobile communication terminal, a PDA, or a door monitoring device. It has an effect that it can be applied to imaging optical systems such as various surveillance cameras such as rear surveillance.

In addition, according to the present invention, since the optical system can be miniaturized and thinned, and has a wide angle of view, an excellent performance can be obtained even in a sensing optical system capable of detecting a movement of a subject.

And. According to the present invention, the image of the peripheral part of the sensor is clear by sufficiently securing the peripheral light amount, and the peripheral part of the sensor can detect the movement of the subject.

In addition, by using a plastic lens, not only can be reduced in weight, but also easy to manufacture, mass production is possible, and the manufacturing cost is low.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 to 5 and 8 are lens configuration diagrams of an optical system having a wide-angle lens according to various embodiments of the present invention.

In the lens configuration diagram below, the thickness, size, and shape of the lens may be somewhat exaggerated for description, and in particular, the shape of the spherical or aspherical surface shown in the lens configuration is merely an example and is not limited thereto.

The optical system having the wide-angle lens according to the present invention is not only a camera module mounted in a small device such as a mobile communication terminal or a PDA, but also an imaging system used for various surveillance cameras such as door monitoring and vehicle rear monitoring. It can also be used in the sensing optical system for detecting the movement of the.

2 to 5 and 8, the optical system according to an embodiment of the present invention is an aperture stop (AS), a wide-angle lens (L), an imaging surface (blocking the unnecessary light in order from the object side) IP is located. At this time, in the optical system according to the present invention, only one wide-angle lens L is used as a refractive lens having a curved refractive surface.

In addition, the imaging surface IP corresponds to an image sensor or an optical sensor, and the sensor detects light passing through the wide-angle lens L and converts the light into an electrical signal. Or CMOS (Compensation Metal Semiconductor).

Meanwhile, as shown in FIG. 8, an optical filter (OF) corresponding to an infrared filter, a cover glass, or the like may be installed between the wide-angle lens L and the imaging surface IP to improve optical performance. The optical filter OF is considered to have no influence on the optical characteristics of the optical system according to the present invention.

An optical system having a wide-angle lens according to an embodiment of the present invention has a wide shooting range, that is, a large field of view, suitable for imaging optical systems such as surveillance cameras, sensing optical systems, and the like. have. That is, the optical system according to the present invention needs to have a large field of view and a short focal length in order to be mounted on a mobile device such as a portable mobile communication terminal, a PDA, or a surveillance camera.

To this end, the optical system according to the present invention has a shape in which the object side surface 2 is convex toward the object side, as shown in FIGS. 2 to 5 and 8, and the upper side 3 is convex upward on the optical axis and the peripheral portion thereof. A wide-angle lens (L) having a concave or convex shape toward the image is provided.

In addition, in order to correct various aberrations such as spherical aberration and distortion, and to ensure proper resolution, at least one of the refractive surfaces of the object-side surface 2 and the image-side surface 3 of the wide-angle lens L is preferably made of an aspherical surface. In this case, although the image side surface 3 of the wide-angle lens L may be formed as an aspherical surface, as in the first to fifth embodiments to be described later, both the object side surface 2 and the image side surface 3 are formed as aspherical surfaces. May be

The object-side surface 2 of the wide-angle lens L collects the light incident from the object side to have a short focal length, and the image-side surface 3 collects the collected light to an image plane IP Spread wide to the periphery. To this end, the image side surface 3 of the wide-angle lens (L) preferably has one or more inflection points.

On the other hand, the optical system having a wide-angle lens according to the present invention can be used not only for the imaging optical system, but also for the sensing optical system for sensing the movement of the subject.

An example in which an optical system having a wide-angle lens according to the present invention is applied to an optical pointing device as an example of a sensing optical system will be described with reference to FIG. 11.

As shown in FIG. 11, the optical pointing device collects the light reflected from the subject 120 by the light source 110 irradiating light and the light emitted from the light source 110, and the wide-angle lens according to the present invention. The lens unit 130 is applied to the optical system having an optical sensor and an optical sensor (image sensor) 140 for detecting the movement of the subject 120 by detecting the image collected by the lens unit 130 (Fig. Corresponding to the upper surface IP].

The light source unit 110 may be formed of a high brightness light emitting diode (LED). However, the light source unit 110 is not limited thereto as long as the reflected light is recognized by the light sensor 140. Similarly, if the optical sensor 140 can also sense the movement of the subject 120 by reading the sensitivity of light, the type thereof is not particularly limited.

In addition, the subject 120 may be formed of a pad or the like corresponding to the ground or the ground like a general optical mouse. In this case, the subject 120 may be directly moved to sense the relative movement of the subject 120.

However, since the optical system having the wide-angle lens according to the present invention is particularly small, the optical system may be applied to an optical pointing device mounted on a mobile device such as a mobile communication terminal. In this case, the surface of the finger may correspond to the subject 120. Can be. That is, the pointing device may be configured to detect a movement of a finger surface corresponding to the subject 120 and perform a pointing (direction) operation while the pointing device is fixed.

On the other hand, the lens unit 130 is applied to the optical system having a wide-angle lens according to the present invention, it is possible not only to secure a wide field of view suitable for the pointing operation, it is also possible to miniaturize the pointing device.

That is, the lens unit 130 includes the wide-angle lens L as described above, and only the wide-angle lens L performs the function of the refractive lens. The configuration of the wide-angle lens L is as described above, and detailed description is omitted in order to avoid duplication.

Look at the effect of the following Conditional Expressions 1 to 5 under such an overall configuration.

Conditional Expression 1 1.0 < TL / f <3.5

Here, TL is the distance from the aperture stop AS to the imaging surface IP, and f is the focal length of the optical system.

Conditional Expression 1 relates to the dimension of the optical axis direction of the optical system, and is a condition regarding the miniaturization of the optical system according to the present invention.

If the deviation from the upper limit of the conditional formula 1, it is contrary to the miniaturization of the features of the present invention, the camera module mounted on a small mobile device such as a mobile communication terminal, PDA, or an optical system for imaging such as various surveillance cameras such as doors, vehicle rear monitoring, Or it is difficult to apply to the sensing optical system for detecting the movement of the subject.

On the contrary, if the condition is outside the lower limit of Equation 1, the ratio of ambient light becomes small, making it difficult to detect an image in the image sensor (light sensor) and deteriorating the manufacturability.

Conditional Expression 2 # 30 < FOV Of TL  <150

Here, FOV is a diagonal angle of view of the optical system, and TL is a distance from the aperture stop AS to the image plane IP.

Conditional Expression 2 is a conditional expression regarding the angle of view, and when it is out of the lower limit of Conditional Expression 2, the recognition distance of the subject becomes far, and the efficiency of the optical system is reduced. Lose.

조건 1.49 <N <1.67

Where N is the refractive index of the wide-angle lens.

Condition 3 is related to the material as a condition regarding the refractive index of the wide-angle lens (L).

That is, Conditional Expression 3 is for forming the wide-angle lens L from a plastic material, and considering the fact that at least one of the refractive surfaces of the wide-angle lens L is formed as an aspherical surface, it is a condition for manufacturing the lens with low cost and high productivity. .

If the upper and lower limits of Conditional Equation 3 are exceeded, the material cost increases, which is contrary to the viewpoint of low cost.

Conditional Expression 4 2.5 < TL / f <3.5

Here, TL is the distance from the aperture stop AS to the imaging surface IP, and f is the focal length of the optical system.

Conditional Expression 4, like Conditional Expression 1, relates to the dimensions of the optical axis direction of the optical system, and is a condition for miniaturization more suitable when used in the sensing optical system for detecting the movement of a subject.

If it is out of the upper limit of Conditional Expression 4, it is contrary to the miniaturization, which is a characteristic of the present invention, as in Conditional Expression 1, and it is difficult to be applied to a sensing optical system or an imaging optical system mounted on a camera module of a micro mobile device or used in various surveillance cameras.

On the contrary, if the condition is outside the lower limit of Equation 4, the amount of ambient light becomes small, making it difficult to detect an image in the image sensor (optical sensor), which makes it particularly difficult to apply to the sensing optical system.

Conditional Expression 5 80 < FOV Of TL  <150

Here, FOV is a diagonal angle of view of the optical system, and TL is a distance from the aperture stop AS to the image plane IP.

Conditional Expression 5 is a conditional expression relating to a photographing range (view angle) similarly to Conditional Expression 2, and is a condition regarding a photographing range more suitable when used in a sensing optical system that detects a movement of a subject.

If the deviation from the lower limit of Conditional Equation 5 is reduced, the efficiency of the optical system is reduced because the subject's recognition distance is far away. If the deviation is exceeded, the amount of ambient light decreases and the image around the image sensor (light sensor) is darkened. Becomes difficult.

Hereinafter, the optical system having the wide-angle lens L will be described through specific numerical examples.

As described above, all of the wide-angle lenses L of Examples 1 to 5 have a shape in which the object side surface 2 is convex toward the object side, and the image side surface 3 is convex upward on the optical axis and from the peripheral part to the image side. It has a concave shape. In particular, the refractive surface of at least one of the object-side surface 2 and the upper surface 3 is aspheric.

In addition, an opening diaphragm AS is provided in front of the object-side surface 2 of the wide-angle lens L to block unnecessary light, and an imaging surface is formed behind the image-side surface 3. (IP) is located. In this case, the imaging surface IP corresponds to an image sensor or an optical sensor, and the sensor detects light passing through the wide-angle lens L and converts the light into an electrical signal. Or CMOS (Compensation Metal Semiconductor).

8, an optical filter OF corresponding to an infrared filter, a cover glass, or the like may be provided between the wide-angle lens L and the imaging surface IP. OF) does not appear to affect the optical properties of the optical system according to the present invention in principle.

The aspherical surface used in each of the following examples is obtained from well-known Equation 1, and is used for the Conic constant (K) and the aspherical coefficients (A, B, C, D, and E), followed by the numerals. 'Represents a power of 10. For example, E21 has a 10 ^21, E-02 indicates the ^10-2.

Where Z is the distance from the apex of the lens to the optical axis direction

        Y: distance in the direction perpendicular to the optical axis

        c: inverse of the radius of curvature r at the vertex of the lens

        K: Conic constant

        A, B, C, D, E, F: Aspheric coefficient

[First Example ]

Table 1 below shows a numerical example of the optical system having a wide-angle lens according to the first embodiment of the present invention.

2 is a lens configuration diagram showing the lens arrangement of the optical system according to the first embodiment of the present invention.

In the first embodiment, the total focal length f of the optical system is 0.309 mm, the diagonal angle of view FOV is 100 °, and the distance from the aperture stop AS to the image plane IP is total. length (TL) is 0.9 mm.

In Table 1, * represents an aspherical surface, and the values of the koenic constant (K) and the aspherical coefficients (A, B, C, D, and E) according to Equation 1 are shown in Table 2 below. In Table 1, the distance between the image side surface 3 and the imaging surface 4 of the wide-angle lens is a value including the defocusing amount.

[Second Example ]

Table 3 below shows a numerical example of the optical system including the wide-angle lens according to the second embodiment of the present invention.

3 is a lens configuration diagram showing the lens arrangement of the optical system according to the second embodiment of the present invention.

In the second embodiment, the total focal length f of the optical system is 0.309 mm, the diagonal angle of view FOV is 100 °, and the distance TL from the aperture stop AS to the image plane IP is 1.01 mm. .

In Table 3, * represents an aspherical surface, and the values of the koenic constant (K) and the aspherical coefficients (A, B, C, D, and E) according to Equation 1 are shown in Table 4 below. In Table 3, the distance between the image side surface 3 and the imaging surface 4 of the wide-angle lens is a value including the defocusing amount.

[Third Example ]

Table 5 below shows a numerical example of the optical system having a wide-angle lens according to the third embodiment of the present invention.

4 is a lens configuration diagram showing a lens arrangement of an optical system having a wide-angle lens according to a third embodiment of the present invention.

In the third embodiment, the total focal length f of the optical system is 0.305 mm, the diagonal angle of view FOV is 100 °, and the distance TL from the aperture stop AS to the image plane IP is 0.96 mm. .

In Table 5, * represents an aspherical surface, and the values of the koenic constant (K) and the aspherical coefficients (A, B, C, D, and E) according to Equation 1 are shown in Table 6 below. In Table 5, the distance between the image side surface 3 and the imaging surface 4 of the wide-angle lens is a value including the defocusing amount.

[4th Example ]

Table 7 below shows a numerical example of the optical system having a wide-angle lens according to the fourth embodiment of the present invention.

5 is a lens configuration diagram illustrating a lens arrangement of an optical system having a wide-angle lens according to a fourth exemplary embodiment of the present invention, and FIG. 6 is a fourth aberration diagram of the fourth exemplary embodiment illustrated in FIG. 5. (a) shows spherical aberration, (b) shows astigmatism, and (c) shows distortion, and FIG. 7 is a graph showing MTF characteristics of the fourth embodiment shown in FIG.

Here, MTF (Modulation Transfer Function) depends on the spatial frequency of the cycle per millimeter, and is a value defined by the following equation (2) between the maximum intensity (Max) and the minimum intensity (Min) of light.

In other words, if the MTF is 1, it is most ideal. If the MTF value decreases, the resolution drops.

On the other hand, "S" in the astigmatism drawings below represents sagittal, and "T" represents tangential.

In the fourth embodiment, the total focal length f of the optical system is 0.75 mm, the diagonal angle of view FOV is 66 °, and the distance TL from the aperture stop AS to the image plane IP is 1.2373 mm.

In Table 7, * represents an aspherical surface, and the values of the conic constant K and the aspherical coefficients A, B, C, D, E, and F according to Equation 1 are shown in Table 8 below.

[5th Example ]

Table 9 below shows a numerical example of the optical system having a wide-angle lens according to the fifth embodiment of the present invention.

8 is a lens configuration diagram illustrating a lens arrangement of an optical system having a wide-angle lens according to a fifth embodiment of the present invention, and FIG. 9 is a view illustrating a fifth aberration diagram of the fifth embodiment shown in FIG. 8. (a) shows spherical aberration, (b) shows astigmatism, and (c) shows distortion, and FIG. 10 is an MTF graph of the fifth embodiment shown in FIG.

In the fifth embodiment, the total focal length f of the optical system is 1.2818 mm, the diagonal angle of view FOV is 66 °, and the distance TL from the aperture stop AS to the image plane IP is 1.939 mm. .

In Table 9, * represents an aspherical surface, and the values of the koenic constant (K) and the aspherical coefficients (A, B, C, D, and E) according to Equation 1 are shown in Table 10 below.

The values of Conditional Expressions 1 to 5 for the first to fifth embodiments are shown in Table 11 below.

As shown in Table 11 above, the first to fifth embodiments of the present invention satisfy conditional expressions 1 to 5, and in particular, an optical system having a wide-angle lens according to the present invention is used as a sensing optical system. It can be seen that Examples 1 to 3 satisfy Conditional Expressions 3 to 5.

Meanwhile, the first to third embodiments, which are suitable embodiments when the optical system according to the present invention is used as the sensing optical system, are compared with the peripheral portion (1.0 field) when compared with the amount of light on the optical axis (0.0 field), as shown in Table 12 below. The amount of light at is maintained at a high level of more than 50%. Further, the fourth and fifth embodiments are also more suitable for the optical system for imaging, but the amount of light at the peripheral portion (1.0 field) is maintained at a high level of approximately 50% (49% or more) as compared with the light amount on the optical axis (0.0 field). It can be confirmed that the optical system for sensing can be used sufficiently.

Therefore, the optical system having the wide-angle lens according to the present invention can confirm that the movement of the subject can be well detected not only in the vicinity of the optical axis but also in the periphery near the effective mirror, and can be effectively used for the sensing optical system.

The optical system of the first to third embodiments is a particularly suitable embodiment for the sensing optical system, but it is obvious that this embodiment can be applied to imaging optical systems such as surveillance cameras as in the optical systems of the fourth and fifth embodiments.

In addition, in the fourth and fifth embodiments, since the characteristics of the aberration are excellent as shown in Figs. 6 and 9, and the resolution is excellent as shown in Figs. Suitable for However, although the optical system of the fourth and fifth embodiments is a particularly suitable embodiment for the optical system for imaging, such an embodiment can be applied to the optical system for sensing as described in Table 12.

While the invention has been shown and described with respect to particular embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I want to make it clear.

1 is a schematic view of a typical optical pointing device.

2 is a lens configuration diagram of an optical system having a wide-angle lens according to a first embodiment of the present invention.

3 is a lens configuration diagram of an optical system having a wide-angle lens according to a second embodiment of the present invention.

4 is a lens configuration diagram of an optical system including a wide-angle lens according to a third embodiment of the present invention.

5 is a lens configuration of an optical system having a wide-angle lens according to a fourth embodiment of the present invention.

FIG. 6 is various aberration diagrams of the optical system illustrated in FIG. 5.

(a) is spherical aberration, (b) is astigmatism, and (c) is aberration diagram showing distortion.

7 is a graph showing the MTF characteristics of the optical system shown in FIG.

8 is a lens configuration diagram of an optical system including a wide-angle lens according to a fifth embodiment of the present invention.

FIG. 9 is a diagram of various aberrations of the optical system illustrated in FIG. 8;

(a) is spherical aberration, (b) is astigmatism, and (c) is aberration diagram showing distortion.

10 is a graph showing the MTF characteristics of the optical system shown in FIG.

11 is a schematic view of an optical pointing device in which an optical system having a wide-angle lens according to the present invention is used.

Explanation of symbols on the main parts of the drawings

110 ... light source 120 ... subject

130 ... Lens section 140 ... Light sensor

L ... wide-angle lens AS ... aperture aperture

IP ... imaging plane OF ... optical filter

1,2,3,4,5,6 ... face number

Claims (15)

A wide-angle lens having an object-side surface convex toward the object side, an image-side surface convex upward from the optical axis, and at least one refractive surface of the object-side surface and the image-side surface being an aspherical surface; And a wide-angle lens including only one wide-angle lens as a refractive lens. The method of claim 1, And an image-side surface of the wide-angle lens has a concave or convex shape from the periphery toward the image side. The method according to claim 1 or 2, When the object-side surface of the wide-angle lens is disposed behind the aperture stop, and the image-side surface of the wide-angle lens is disposed in front of the image forming surface, An optical system comprising a wide-angle lens, wherein the following conditional expression 1 is satisfied with respect to the dimension in the optical axis direction. Conditional Expression 1 1.0 <TL / f <3.5 TL: distance from the aperture stop to the image plane         f: focal length of optical system The method according to claim 1 or 2, When the object-side surface of the wide-angle lens is disposed behind the aperture stop, and the image-side surface of the wide-angle lens is disposed in front of the image forming surface, An optical system having a wide-angle lens, characterized by satisfying the following Conditional Expression 2 for a diagonal angle of view. Conditional Expression 2 # 30 <FOV / TL <150 Where: FOV: Diagonal Angle of View         TL: distance from the aperture stop to the image plane The method according to claim 1 or 2, An optical system having a wide-angle lens, wherein the following Conditional Expression 3 is satisfied with respect to the refractive index of the wide-angle lens. 조건 1.49 <N <1.67 Where N is the refractive index of the wide-angle lens The method according to claim 1 or 2, The wide-angle lens collects the light reflected from the subject to form an image on the optical sensor, The object is an optical system having a wide-angle lens, characterized in that for reflecting the light emitted from the light source. The method of claim 6, When the object-side surface of the wide-angle lens is disposed behind the aperture stop, and the image-side surface of the wide-angle lens is disposed in front of the image forming surface, An optical system comprising a wide-angle lens, wherein the following Conditional Expression 4 is satisfied with respect to the dimension in the optical axis direction. Conditional Expression 4 2.5 <TL / f <3.5 TL: distance from the aperture stop to the image plane         f: focal length of optical system The method of claim 7, wherein An optical system having a wide-angle lens, which satisfies the following Conditional Expression 3 with respect to the refractive index of the wide-angle lens, and the following Conditional Expression 5 with respect to a diagonal angle of view. 조건 1.49 <N <1.67 [Condition 5] # 80 <FOV / TL <150 Where N is the refractive index of the wide-angle lens         FOV: Diagonal Angle of View         TL: distance from the aperture stop to the image plane And an object side surface having a convex shape on the object side, and an image side surface having a convex shape on the optical axis, wherein at least one refractive surface of the object side surface and the image side surface is formed of an aspherical surface. The method of claim 9, The image side surface is a wide-angle lens, characterized in that the concave or convex shape from the peripheral portion to the image side. The method of claim 9 or 10, When the object side surface is disposed behind the aperture stop and the image side surface is disposed in front of the image forming surface, the wide angle lens satisfies the following conditional expression 1 in terms of the optical axis direction. Conditional Expression 1 1.0 <TL / f <3.5 TL: distance from the aperture stop to the image plane         f: focal length of optical system The method of claim 9 or 10, When the object side surface is disposed behind the aperture stop and the image side surface is disposed in front of the image forming surface, a wide angle lens is satisfied with respect to the following conditional expression 4 in terms of the optical axis direction. Conditional Expression 4 2.5 <TL / f <3.5 TL: distance from the aperture stop to the image plane         f: focal length of optical system The method of claim 11, And the object side surface is disposed behind the aperture stop, and the image side surface is disposed in front of the image forming surface, and satisfies the following conditional expression 2 for a diagonal angle of view. Conditional Expression 2 # 30 <FOV / TL <150 Where: FOV: Diagonal Angle of View         TL: distance from the aperture stop to the image plane The method of claim 12, And the object side surface is disposed behind the aperture stop, and the image side surface is disposed in front of the image forming surface, and satisfies the following conditional expression 5 for a diagonal angle of view. [Condition 5] # 80 <FOV / TL <150 Where: FOV: Diagonal Angle of View         TL: distance from the aperture stop to the image plane The method of claim 9 or 10, A wide-angle lens characterized by satisfying the following Conditional Expression 3 regarding the refractive index. 조건 1.49 <N <1.67 Where N is the refractive index of the wide-angle lens

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