KR101379678B1 - digital camera - Google Patents

Abstract

A digital camera is disclosed.

The disclosed digital camera includes an imaging element having a first aspect ratio; An image of a subject is imaged on the imaging device, and the image is captured by a subject at a first angle of view defined by a first focal length to form a first image corresponding to the first aspect ratio, or defined by a second focal length. A lens optical system capable of zooming to photograph a subject at a second angle of view and to form a second image corresponding to a second aspect ratio smaller than the first aspect ratio, and having negative distortion; A zooming instruction unit for indicating a first shooting mode according to the first angle of view and a second shooting mode according to a second angle of view; And a correction unit for correcting the negative distortion of the image formed in the imaging device.

Description

Digital camera {Digital camera}

The present invention relates to a digital camera capable of adjusting the aspect ratio of the screen output.

In general, a screen size having a 4: 3 aspect ratio is used as a screen of an imaging optical device such as a digital camera or a mobile phone camera. An imaging device such as a CCD or a CMOS having a 4: 3 size is used for the imaging optical device. However, recently, various technologies such as HDTV, satellite broadcasting, and the like have been developed, and a wider size of 16: 9 is preferred for such a new broadcasting scheme. While demand for 16: 9 wide screens is increasing, imaging devices still use 4: 3 sizes. In this case, the 4: 3 size image must be converted to the 16: 9 size image.

FIG. 1 is a diagram for describing a method for displaying a screen having an aspect ratio (a: b ') of 16: 9 by using an imaging device 100 having an aspect ratio (a: b) of 4: 3. In the 16; 9 mode, a method of implementing a 16: 9 screen (area B) by blocking light entering the upper and lower portions (area A) of the imaging device is used. When using this method, the amount of light entering the imaging device is reduced, and there is a problem of reducing the number of pixels of the imaging device.

The present invention provides a digital camera capable of adjusting the aspect ratio of a screen without changing the number of pixels for displaying an image.

A digital camera according to an embodiment of the present invention, an imaging device having a first aspect ratio; An image of a subject is imaged on the imaging device, and the image is captured by a subject at a first angle of view defined by a first focal length to form a first image corresponding to the first aspect ratio, or defined by a second focal length. A lens optical system capable of zooming to photograph a subject at a second angle of view and to form a second image corresponding to a second aspect ratio smaller than the first aspect ratio, and having negative distortion; A zooming instruction unit for indicating a first shooting mode according to the first angle of view and a second shooting mode according to a second angle of view; And a correction unit for correcting the negative distortion of the image formed in the imaging device.

The negative distortion may range from -15% to -9%.

The first aspect ratio may be 4: 3, and the second aspect ratio may be 16: 9.

The lens optical system may include first to fourth lens groups having positive, negative, positive, and positive refractive powers, and the first lens group may include at least one bonding lens.

The focal length of the bonded lens may range from 90 mm to 150 mm.

The lens optical system may include first to third lens groups having negative, positive and positive refractive powers, and the first lens group may include at least one lens having negative refractive power.

The focal length of the lens having negative refractive power may range from -9.5 mm to -8.0 mm.

Hereinafter, a digital camera according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 2, the digital camera according to the present invention includes an imaging device 10 on which an image is formed, a lens optical system 20 for forming an image on the imaging device, and a zooming for zooming the lens optical system 20. Including the indicating unit 30. The imaging device 10 has a first aspect ratio, for example, an aspect ratio of 4: 3, and a charge coupled device (CCD) or a CMOS (CMOS) may be used. The lens optical system can zoom and cause negative distortion on an image of a subject to be imaged on the imaging device. The lens optical system includes a first photographing mode for photographing a subject at a first angle of view defined by a first focal length and a second photographing mode for photographing a subject at a second angle of view defined by a second focal length. In the first photographing mode, the imaging device 10 forms an image corresponding to the first aspect ratio, and in the second photographing mode, a second image corresponding to a second aspect ratio smaller than the first aspect ratio is formed. The lens optical system 20 gives negative distortion to the image of the subject to reduce the image. The negative distortion may be determined according to the difference between the first aspect ratio and the second aspect ratio, and may range from -15% to -9%. This is to form a second image corresponding to the second aspect ratio by giving sufficient distortion to the photographed image of the subject, and after forming the image on the imaging device, adjusting the aspect ratio without deteriorating the angle of view and the number of pixels through distortion correction by digital signal processing. can do. Referring to FIG. 3, a second image I ₁ having negative distortion caused by the lens optical system 20 in the second photographing mode is input to the imaging device 10, and the second image I ₁ is distortion corrected. The distortion is corrected by the element 40 and then displayed on the screen according to the selected screen mode. The distortion corrected image is indicated by I ₂ . As shown in FIG. 3, the image photographed at the second angle of view is distorted and imaged in the imaging device without being cut off.

4 shows a lens optical system according to a first embodiment of the present invention. The lens optical system 20 includes first to fourth lens groups G1, G2, G3, and G4 having positive, negative, positive, and positive refractive powers, and can zoom. The first lens group G1 includes at least one bonding lens. For example, the first lens group G1 includes first to third lenses 1, 2, and 3, and the first lens 1 and the second lens 2 are combined lenses C1. ) The focal length of the bonding lens C1 may range from 90 mm to 150 mm. When the focal length is smaller than 90mm, the power of the lens group increases, so that the distortion becomes small, making it difficult to implement a distorted image for a desired aspect ratio. If the focal length is larger than 200mm, the power is small, so the distortion is large, and there is an advantage in controlling the aspect ratio, but it becomes difficult to miniaturize the optical system. 5 shows aberration diagrams of the lens optical system according to the first embodiment.

An image distorted through the lens optical system 20 is formed on the imaging device 10. Distortion and angle of view are adjusted according to the shooting mode. For example, the first aspect ratio may be 4: 3 and the second aspect ratio may be 16: 9. In the first photographing mode, the subject is photographed at the first angle of view, and in the second photographing mode, the subject is photographed at the second angle of view, and the second angle of view is wider than the first angle of view. When the captured image is to be viewed on the 16: 9 screen, the second shooting mode is selected to shoot. In the second photographing mode, the image photographed at the second angle of view is negatively distorted and imaged on the imaging device. The negative distortion ranges from -15% to -9% and can be adjusted according to the aspect ratio in the second photographing mode. When the second aspect ratio is 16: 9, when the distortion in the second shooting mode is larger than -9%, the image corresponding to 16: 9 is not corrected. When the second aspect ratio is smaller than -15%, the distortion is corrected. The correction may be excessive and image quality may deteriorate.

 6 shows another embodiment of a lens optical system including a group 4 lens, and FIG. 7 shows aberration diagrams of the lens optical system.

8 illustrates an example in which the lens optical system 20 includes first to third lens groups G1, G2, and G3 having negative, positive, and positive refractive powers. The first lens group G1 includes a lens having at least one negative refractive power, and the focal length of the lens ranges from -9.5 to -8.0 mm. When the focal length is larger than -8.0 mm, the refractive power of the lens group becomes large, so that the distortion becomes small and the performance deteriorates. In the case of smaller than -9.5 mm, the refractive power becomes small, so that the performance is improved, but miniaturization of the optical system becomes difficult.

The definitions of aspherical surfaces in the embodiment of the present invention are as follows.

The aspherical shape of the zoom lens according to the present invention can be expressed by the following equation with the x-axis as the optical axis direction and the y-axis as the direction perpendicular to the optical axis direction. Where x is the distance from the vertex of the lens to the optical axis direction, y is the distance in the direction perpendicular to the optical axis, k is a conic constant, A, B, C and D are aspheric coefficients, and c represents the inverse number (1 / R) of the radius of curvature at the apex of the lens.

The present invention specifically includes lenses according to optimization conditions for implementing miniaturization of the zoom lens through various embodiments according to the following designs.

Hereinafter, f denotes the combined focal length of the entire lens system, FNO denotes the F number, R denotes the radius of curvature, and Dn denotes the center thickness of the lens or the distance between the lens and the lens, respectively. Sto represents an aperture, D1, D2, D3, D4, and D5 represent a variable distance, and * represents an aspherical surface.

≪ Embodiment 1 >

 f; 4.1400 16.1372 64.1707

FNO; 2.9096 4.7385 6.9080

  Lens surface R Dn Glass

   obj infinity D1-

     1 59.042 0.947 909 268.272737

     2 22.010 4.000 834810.427207

     3 398.407 0.118-

     4 24.777 2.363 506801.790201

     5 92.418 D2-

     6 * -146.024 0.789 805844.452276

     7 * 6.001 2.517-

     8 -14.718 0.632 658345.576741

     9 10.921 0.892-

    10 12.755 1.688 846663.237848

    11 -61.458 0.700 713000.539389

    12 -253.692 D3-

   sto infinity 0.150-

    14 * 6.956 2.700 648797.584512

    15 * -25.583 0.262-

    16 13.387 1.887 496997.816084

    17 -36.054 0.500 860874.306272

    18 5.838 0.248-

    19 13.338 1.700 526 263.525413

    20 -19.995 D4-

    21 * 336.804 1.445 550352.701008

    22 -10.890 D5-

    23 infinity 0.789 516798.641983

    24 infinity-

The following shows the aspherical coefficients.

  Lens face

     6 K: -605.277891

         A: 2.727001e-005 B: 1.339952e-007 C: -7.015570e-010

         D: -1.016942e-011

     7 K: -0.014698

         A: -1.618051e-004 B: -4.077212e-006 C: -1.217523e-008

         D: 2.817257e-009

    14 K: -1.000000

        A: -2.028860e-005 B: -1.734778e-006 C: 2.100951e-009

         D: 0.000000e + 000

    15 K: -1.000000

         A: 1.229912e-005 B: -2.055859e-006 C: 1.708299e-009

         D: 0.000000e + 000

    21 K: 0.000000

        A: -5.857059e-004 B: 1.043012e-005 C: -8.630426e-007

        D: 2.711687e-008

Next, the variable distances D1, D2, D3, D4, and D5 of the zoom lens according to the first embodiment are shown for the wide-angle end, the intermediate end, and the telephoto end.

  Variable distance wide-angle end telephoto end

     D1 infinity infinity infinity

     D2 0.600 12.769 23.032

     D3 16.702 6.984 1.263

     D4 6.127 17.183 28.864

     D5 0.500 0.150 0.150

≪ Embodiment 2 >

 f; 4.0430 16.0372 64.2065

FNO 2.9065 5.1181 7.0807

 Lens surface R Dn Glass

   obj infinity D1-

     1 61.821 0.947 906810.274081

     2 21.906 4.000 834810.427207

     3 769.998 0.118-

     4 24.866 1.711 501633.803510

     5 99.640 D2-

     6 * -129.857 0.789 803918.453624

     7 * 6.157 2.711-

     8 -14.283 0.632 657066.577757

     9 10.755 0.849-

    10 12.368 1.831 846663.237848

    11 -60.267 0.700 713000.539389

    12 infinity D3-

   sto infinity 0.150-

    14 * 6.946 2.700 648952.584382

    15 * -26.321 0.238-

    16 12.870 1.901 496997.816084

    17 -39.789 0.500 858973.302125

    18 5.777 0.263-

    19 13.213 1.700 533320.504101

    20 -20.135 D4-

    21 * -124.754 2.112 523674.751278

    22 -10.135 D5-

    23 infinity 0.789 516798.641983

    24 infinity

  Lens face

     6 K: -208.216298

         A: 3.326562e-005 B: 2.959123e-007 C: -1.176842e-010

         D: -4.705344e-011

     7 K: 0.038651

         A: -1.413214e-004 B: -2.414092e-006 C: -2.225768e-008

         D: 6.539683e-009

    14 K: -1.000000

         A: -2.028860e-005 B: -1.734778e-006 C: 2.100951e-009

         D: 0.000000e + 000

    15 K: -1.000000

         A: 1.229912e-005 B: -2.055859e-006 C: 1.708299e-009

         D: 0.000000e + 000

    21 K: 0.000000

        A: -5.347078e-004 B: 1.043598e-005 C: -8.892467e-007

        D: 2.930431e-008

   Variable distance wide-angle intermediate telephoto

     D1 infinity infinity infinity

     D2 0.600 10.572 22.918

     D3 16.406 6.024 1.263

     D4 5.153 18.485 28.713

     D5 4.152 3.096 1.854

≪ Third Embodiment >

 f; 6.0001 9.7584 16.6798

FNO 3.3357 4.4457 6.1467

  Lens surface R Dn Glass

   obj infinity D1-

     1 -24.842 0.500 502608.678431

     2 5.491 1.701-

     3 * 20.396 2.394 819837.340834

     4 * 543.274 D2-

   sto infinity 0.397-

     6 4.382 1.540 825207.439486

     7 -19.712 0.500 782939.259608

     8 6.184 0.289-

     9 * -30.308 0.777 579910.504812

    10 * -26.900 D3-

    11 19.352 1.800 496997.816084

    12 -24.579 D4-

    13 infinity 0.300 516798.641983

    14 infinity 0.500-

    15 infinity 0.500 516798.641983

    16 infinity

  Lens face

     3 K: 3.991365

          A: 1.236457e-004 B: -1.831147e-005 C: 1.717528e-006

          D: -4.542397e-008

     4 K: 0.000000

          A: -1.931739e-004 B: -2.399374e-005 C: 1.854340e-006

          D: -6.683890e-008

     9 K: 0.000000

          A: 3.483632e-003 B: 6.190985e-004 C: -3.899381e-005

          D: -1.559442e-006

    10 K: 0.000000

         A: 7.309402e-003 B: 7.827382e-004 C: 3.721940e-005

         D: -4.785345e-006

  Variable distance wide-angle end telephoto end

     D1 infinity infinity infinity

     D2 13.147 6.755 1.200

     D3 5.806 11.608 18.037

     D4 3.242 1.361 0.100

<Fourth Embodiment>

 f; 5.9789 9.8666 17.9368

FNO 3.3053 4.3544 6.1833

  Lens surface R Dn Glass

   obj infinity D1-

     1 -23.353 0.500 522344.649258

     2 5.532 1.631-

     3 * 19.891 2.397 822 316.318203

     4 * 544.210 D2-

   sto infinity 0.161-

     6 4.407 1.499 824856.439707

     7 -17.233 0.500 774145.261320

     8 6.234 0.299-

     9 * -27.582 0.764 580011.564709

    10 * -24.766 D3-

    11 21.200 1.800 496997.816084

    12 -23.115 D4-

    13 infinity 0.300 BSC7_HOYA

    14 infinity 0.500-

    15 infinity 0.500 BSC7_HOYA

    16 infinity

   Lens face

     3 K: 3.639191

          A: 1.159165e-004 B: -1.831085e-005 C: 1.702646e-006

          D: -4.555819e-008

     4 K: 0.000000

          A: -2.079995e-004 B: -2.428738e-005 C: 1.829733e-006

          D: -6.648625e-008

     9 K: 0.000000

          A: 3.521390e-003 B: 6.086325e-004 C: -4.062501e-005

          D: -9.973923e-007

    10 K: 0.000000

          A: 7.293330e-003 B: 7.696860e-004 C: 3.194562e-005

          D: -3.700199e-006

   Variable distance wide-angle end telephoto end

     D1 infinity infinity infinity

     D2 13.147 6.755 1.200

     D3 6.069 11.969 19.778

     D4 3.221 1.306 0.276

The present invention provides a digital camera that can adjust the aspect ratio of the screen without deteriorating the angle of view or the number of pixels. When outputting a wide screen from a digital camera having an imaging device having an aspect ratio of a: b, the photographed image of the subject is negatively distorted to be imaged on the imaging device and then output to the screen through distortion correction.

The above-described embodiments are merely illustrative, and various modifications and equivalent other embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of protection of the present invention should be determined by the technical idea of the invention described in the following claims.

1 is a view for explaining a conventional aspect ratio adjustment method.

2 is a block diagram of a digital camera according to an embodiment of the present invention.

3 is a view for explaining an aspect ratio adjustment method of a digital camera according to an embodiment of the present invention.

4 shows a lens optical system according to the first embodiment.

5 is an aberration diagram of the lens optical system according to the first embodiment.

6 shows a lens optical system according to the second embodiment.

7 is an aberration diagram of the lens optical system according to the second embodiment.

8 shows a lens optical system according to the third embodiment.

9 is an aberration diagram of the lens optical system according to the third embodiment.

10 illustrates a lens optical system according to the fourth embodiment.

11 is an aberration diagram of the lens optical system according to the fourth embodiment.

Claims (7)

An imaging device having a first aspect ratio; An image of a subject is imaged on the imaging device, and the image is captured by a subject at a first angle of view defined by a first focal length to form a first image corresponding to the first aspect ratio, or defined by a second focal length. A lens optical system capable of zooming to photograph a subject at a second angle of view and to form a second image corresponding to a second aspect ratio smaller than the first aspect ratio, and having negative distortion; A zooming instruction unit for indicating a first shooting mode according to the first angle of view and a second shooting mode according to a second angle of view; And a correction unit for correcting the negative distortion of the image formed on the imaging device. The method according to claim 1, And said negative distortion ranges from -15% to -9%. 3. The method of claim 2, And wherein the first aspect ratio is 4: 3 and the second aspect ratio is 16: 9. 4. The method according to any one of claims 1 to 3, The lens optical system includes a first to fourth lens group having a positive, negative, positive, positive refractive power, wherein the first lens group comprises at least one of the bonding lens. 5. The method of claim 4, And the focal length of the bonded lens is in the range of 90 mm to 150 mm. 4. The method according to any one of claims 1 to 3, The lens optical system may include first to third lens groups having negative, positive, and positive refractive powers, and the first lens group includes at least one lens having negative refractive power. The method according to claim 6, And a focal length of the lens having the negative refractive power ranges from -9.5 mm to -8.0 mm.

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