JP2005020718A - Multifocal imaging device and mobile device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin multifocal imaging device that can be mounted on a mobile such as a cell phone or the like. <P>SOLUTION: The multifocal imaging device comprises: an image sensor placed on the same plane; and a plurality of imaging optical systems for each forming images of different imaging magnifications on different imaging areas on the image sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thin multifocal imaging device and a mobile device.

The miniaturization and high-definition of digital cameras are unknown, and recently, there is a problem of distinguishing between the form as a camera and the mobile phone with a camera (mobile).
Japanese Patent Laid-Open No. 10-107975 JP 2000-102040 A JP 2000-227332 A Japanese Patent Laid-Open No. 2001-61109

The current boundary of segregation is said to be about 1 million pixels, but in reality, mobile-equipped cameras are limited to a fixed focus because of the demand for thinning.
An object of the present invention is to obtain a thin multifocal imaging device that can be mounted on a mobile phone (mobile).

  A multifocal imaging device according to the present invention sets a plurality of different imaging areas on an image sensor arranged on the same plane, and forms a plurality of images with different imaging magnifications on the plurality of imaging areas, respectively. The image forming optical system is provided.

  The plurality of imaging areas are preferably formed on a single image sensor.

  The imaging areas formed by the imaging optical systems that form a plurality of different images can be separated without overlapping each other, or can be partially overlapped and shared.

  In order to mechanically select any one of the plurality of imaging areas, it is preferable to provide means for shielding an optical path other than the selected area.

  In the multifocal imaging device of the present invention, any optical element of each imaging optical system can be modularized with an optical element of an imaging optical system different from the imaging optical system to which the optical element belongs.

  Specifically, for example, on the most object side of a plurality of imaging optical systems, the object side surface is a plane common to each optical system, and the image side surface is a lens surface unique to each optical system. It is preferable to arrange the outer plane common optical element.

  A part of the object-side plane of the outer-plane common optical element can be overlapped as an optical path of a plurality of imaging optical systems, and the planar size can be reduced by overlapping.

  In addition, by arranging a modularized intermediate optical element block having a lens element unique to each imaging optical system between the outer plane common optical element and the image sensor, the configuration is simplified. Assemblability can be improved.

  In the multifocal imaging device of the present invention, according to another aspect, a plurality of imaging optical systems, a first lens module integrated with optical elements for each imaging optical system located on the object side, A second lens module (intermediate optical element block), which is integrated between the lens elements for each imaging optical system, located between the first lens module and the image sensor, and a plurality of imaging optical systems. A single image sensor having an imaging area can be used.

  In order to reduce the cost by making the lens elements in a plurality of imaging optical systems common, each imaging optical system is provided with at least one common lens element that differs only in the relative position in the optical axis direction. The shooting distance and focal length can be changed.

  The plurality of imaging optical systems can vary the shooting distance (focal position or imaging magnification), but it is practical to make the focal distance of at least one optical system different from the focal distance of other optical systems. is there.

  For example, focal lengths corresponding to telephoto, standard, and wide-angle can be given to the plurality of imaging optical systems. Specifically, the focal length of the optical system with the longest focal length is preferably 1.5 times or more the focal length of the optical system with the shortest focal length.

  In addition, a focal length corresponding to a macro can be given to a plurality of imaging optical systems. Specifically, a coupling optical system that focuses on an object point at a distance of 200 times or less of the focal length is preferable.

  In front of the plurality of imaging areas, it is preferable to arrange a single infrared cut filter or a single optical low-pass filter for all the imaging areas in accordance with the properties of the image sensor.

  The multifocal imaging device of the present invention is useful when mounted on a mobile device such as a mobile phone.

  ADVANTAGE OF THE INVENTION According to this invention, the multi-focal imaging device which can be mounted in mobiles, such as a mobile phone, is ultra-thin.

  1 and 2 are conceptual diagrams in which a multifocal color imaging device according to the present invention is mounted on a mobile phone 10. An imaging window 11 is formed on one surface of the mobile phone 10, and an LCD panel 12 as display means is provided on the other surface.

  A multifocal imaging device 20 having four imaging areas (image forming areas) distributed in a plane is located in the imaging window 11 (mobile phone 10). The multifocal imaging device 20 shown in FIGS. 3 to 7 includes, in order from the object side, an outer surface common optical element 21, four different optical elements 22A, 22B, 22C and 22D located on different optical axes, a common red An outer cut filter 23 and a single color image sensor (color CCD, solid-state image sensor) 24 are located.

  The outer-plane common optical element 21 includes an incident surface whose surface on the object side forms a plane 21p, and the image-side surface forms lens surfaces 21A, 21B, 21C, and 21D for each imaging optical system. The surfaces 21A to 21D cooperate with the optical elements 22A to 22D (lens elements for each imaging optical system) to form four imaging optical systems A, B, C, having different focal lengths (imaging magnifications). D is constituted. The infrared cut filter 23 is a single plane parallel plate that covers the four imaging optical systems A to D. Instead of the infrared cut filter 23, a single optical low-pass filter that covers the four imaging optical systems A to D may be installed. Between the four imaging optical systems, an optical path separation wall 28 is installed as an optical path separation element for separating the optical paths.

  Images by the four imaging optical systems A to D are formed in different areas on the single image sensor 24. In this embodiment, the rectangular imaging area of the image sensor 24 is divided into 4 × 2 × 2. Assuming that the size and the number of pixels of the image sensor 24 are 1/4 "(diagonal length) and 1280 × 1024 (≈1.3M), the size and the number of pixels of one imaging area are, for example, 1/8" 640 × 512 (≈0.3M).

  The imaging optical system A has a wide-angle focal length imaging optical system in which the image-side surface 21A of the outer-plane common optical element 21 is a concave surface and the optical element 22A is a positive lens. The object is fixed in a focused state with respect to an object (approximately 1000 times the focal length of the optical system A).

  The imaging optical system B is a macro imaging optical system that constitutes the macro state of the imaging optical system A. The image-side surface 21B and the optical element 22B of the outer-plane common optical element 21 are the same as the surface 21A and the optical element 22A of the imaging optical system A, respectively, but the optical element (positive lens) 22B is moved from the optical element 22A to the object. By disposing it closer, an optical system that focuses on a macro area object (a close object, an object having a focal length of 200 times or less of the focal length of the imaging optical system B) is configured.

  The imaging optical system D is an imaging optical system having a telephoto focal length, and the overall length is increased by forming the image-side surface 21D of the outer-plane common optical element 21 as a convex surface and the optical element 22D as a positive lens. Thus, an imaging optical system having a focal length approximately three times that of the imaging optical system A is formed.

  The image forming optical system C is an image forming optical system having an intermediate focal length between the image forming optical system A and the image forming optical system D. The lens surface 21C and the optical element 22C of the outer plane common optical element 21 include image forming optics. The optical system A is the same as the lens surface 21A and the optical element 22A of the system A, but the optical element (positive lens) 22C is the entire system as a unique optical element positioned closer to the object than the optical element (positive lens) 22A. An imaging optical system having a focal length approximately twice as large as that of the image forming apparatus is formed.

  As shown in FIG. 8, the image sensor 24 is connected to an arithmetic processing unit (CPU) 30. When the release switch 32 is pressed, image signals of four image forming areas on the image sensor 24, that is, A to D are displayed. The image signals of different focal lengths imaged via the are taken into the arithmetic processing unit 30. The selection means 33 selects one of the four image signals in advance or after imaging and displays it on the LCD panel (display means) 12. The arithmetic processing unit 30 is provided with a storage unit 34 and stores the selected image.

  That is, since the images of the imaging optical systems A to D are formed in independent regions of the image sensor 24, a plurality of images can be obtained simultaneously. Of course, it is also possible to obtain an image of only a single imaging optical system by selecting the optical path mechanically or by software selection by image processing or the like.

  The object-side surface of the outer plane common optical element 21 is a plane 21p. As shown in FIGS. 4 to 7, the optical paths of the plurality of imaging optical systems A to D share a part of the lens surface. I use it.

  An ordinary zoom lens camera that changes the focal length by relatively moving each lens group on one optical axis also has a plurality of discontinuous focal length steps when zooming by electric control as in recent years. Therefore, the imaging device of this embodiment can be regarded as a zoom lens camera having a focal length of 3 steps (4 steps). Close to the zoom lens camera. Of course, the stored image signal can be transmitted, but the present invention is not limited to these transmission means.

  9 to 11 are examples in which the optical elements 22A, 22B, 22C, and 22D of the imaging optical systems A to D are configured from a single module (intermediate optical element block, molded body of synthetic resin material). It is. That is, the outer plane common optical element 21 is the first lens module, and the optical elements (lenses) 22A, 22B, 22C, and 22D are formed on the second lens module 22. The same components as those shown in FIGS. 3 to 7 are denoted by the same reference numerals. When modularized in this way, assembly and adjustment are simplified, and a small and thin multifocal imaging device can be easily obtained.

  Next, FIGS. 12 and 13 show an embodiment in which the image sensor 24 is divided into two, that is, an example in which two imaging optical systems A and B are configured. As shown in FIG. 12, the image sensor 24 having an aspect ratio of 4: 3 is divided into two at the center so that the pixels can be used without waste. The infrared cut filter 23 common to the imaging optical systems A and B and the single color image sensor (color CCD) 24 are the same elements as those in the above-described embodiment. The imaging optical systems A and B include a first lens module (outer plane common optical element) 25, a second lens module (intermediate optical element block, a synthetic resin material molded body) 26, and a third lens module (intermediate optical element). The first surface of the first lens module 25 is a flat surface 25p.

  The lens surfaces 25A and 25B of the second surface of the first lens module 25 are the same, and the first lens 26A and the second lens 26B of the second lens module 26 have the same lens shape with different positions in the optical axis direction. The first lens 27A and the second lens 27B of the third lens module 27 are the same. The second lens 26B of the lower image forming optical system B is positioned on the object side of the second lens 26A of the upper image forming optical system A, and the upper image capturing optical system focuses on a distant object. The lower part constitutes a photographing optical system for focusing on a short-distance object (macro). Optical path separation walls 28a, 28b, and 28c are disposed between the first lens module 25 and the second lens module 26, in front of the infrared cut filter 23, and between the infrared cut filter 23 and the image sensor 24, respectively. Thus, images formed by the imaging optical systems A and B are formed on the same image sensor 24 (without overlapping each other).

  With this multifocal imaging device, it is possible to select one of the images at the time of use, and the image with the higher contrast is discriminated softly by simultaneously processing the images at long and short distances. It is also possible to record automatically. In addition, since it is not necessary to mechanically have a focusing mechanism, it is possible to store an optical system capable of photographing an object in a wide distance range with high contrast in a very thin space in the optical axis direction.

  FIG. 14 is a modification of the embodiment of FIGS. 12 and 13, and shows different lens surface shapes that are configured in the first lens module (outer plane common optical element) 25, the second lens module 26, and the third lens module 27. It is an example. Similarly to the embodiment of FIG. 13, the lens surfaces 25A and 25B of the first lens module 25 are the same, and the first lens 26A and the second lens 26B of the second lens module 26 have different positions in the optical axis direction. The same lens shape is formed, and the first lens 27A and the second lens 27B of the third lens module 27 are the same. The second lens 26B of the lower imaging optical system B in the figure is located on the object side from the second lens 26A of the upper imaging optical system A, the upper is a short focal length (wide field angle), and the lower is long. The photographic optical system has a focal length (narrow field angle = high magnification).

  Also in this embodiment, similarly to the above-described long-distance and short-distance optical systems, it is possible to shoot with a wide field angle and a narrow field angle (high magnification) without moving each lens at all. Compared to a conventional photographing optical system that moves a lens and performs zooming and focal length switching, a moving mechanism is not required, so that the optical system can be efficiently stored in a narrow space. Moreover, it is excellent in impact resistance and is advantageous in terms of cost.

  15 and 16, the image sensor 24 is provided with overlapping portions AB in the wide-angle side and telephoto side imaging regions so that the entire imaging device is effectively used while maintaining the aspect ratio of the imaging screen before and after the division. An embodiment is shown. In this embodiment, the two imaging optical systems A and B having a wide-angle focal length and a telephoto focal length are similarly provided with a first lens module (outer plane common optical element) 25, a second lens module 26, and a third lens. The two lens surfaces 25A and 25B of the first lens module 25 and the two lens surfaces 27A and 27B of the third lens module 27 are the same. On the other hand, the two lenses 26 </ b> A and 26 </ b> B of the second lens module 26 are constituted by unique lenses for wide angle and telephoto, respectively.

  In this embodiment, since there is an overlapping portion of the image on the image sensor 24, an optical path selection means (means for shielding the optical path) 29 that shields the optical path other than the selected imaging optical system is connected to the second lens module 26. It is provided between the third lens modules 27.

  FIG. 17 shows an example in which the two image forming areas set in the image sensor 24 are divided without maintaining the aspect ratio of each image forming area while maintaining the aspect ratio of the original image sensor 24.

The image sensor 24 is preferably a single substrate, but may be divided into a plurality of sheets as long as the image sensor 24 is arranged in one plane (upper).

It is an external appearance example when the multifocal imaging device by this invention is mounted in a mobile telephone. It is an external appearance example of the display means (LCD) of the mobile phone. It is a front view which shows one Embodiment of the multifocal imaging device by this invention. FIG. 4 is a cross-sectional view taken along IV-IV in FIG. 3. It is sectional drawing which follows VV of FIG. It is sectional drawing which follows VI-VI of FIG. It is sectional drawing which follows the VII-VII of FIG. 1 is a block diagram of a multifocal imaging device according to the present invention. FIG. It is a perspective view which shows the structural example of the lens module of the multifocal imaging device by this invention. FIG. 10 is a transverse sectional view of the upper imaging optical system in FIG. 9. FIG. 10 is a transverse sectional view of the lower imaging optical system in FIG. 9. 1 is a front view of a multifocal imaging device according to the present invention having two imaging optical systems and independent imaging areas. FIG. It is sectional drawing which follows the XIII-XIII line | wire of FIG. FIG. 14 is a cross-sectional view showing an embodiment of another multifocal imaging device drawn corresponding to the cross-sectional view of FIG. 13. 1 is a front view of a multifocal imaging device according to the present invention in which there are two imaging optical systems and the imaging areas partially overlap. It is sectional drawing which follows the XVI-XVI line of FIG. It is a front view which shows the example which divided | segmented the aspect ratio of each image formation area, maintaining the aspect ratio of the original image sensor, without making two image formation areas set to an image sensor overlap.

Explanation of symbols

ABCD Imaging optical system 10 Mobile phone 11 Imaging window 12 LCD panel (display means)
20 Multifocal imaging device 21 25 External plane common optical element (first lens module)
21p plane 22A 22B 22C 22D optical element (lens element, lens surface)
22 Second lens module (intermediate optical element block)
23 Infrared cut filter 24 Image sensor 26 27 Lens module (intermediate optical element block)
28 28a 28b 28c Optical path separation wall (optical path separation element)
29 Optical path selection means (means to block the optical path)
30 arithmetic processing unit 32 release switch 33 selection means 34 storage means

Claims (18)

A multifocal system comprising: an image sensor arranged on the same plane; and a plurality of imaging optical systems that form images with different imaging magnifications in a plurality of different imaging areas on the image sensor. Imaging device. The multifocal imaging device according to claim 1, wherein the plurality of imaging areas are formed on a single image sensor. 3. The multifocal imaging device according to claim 1, wherein imaging areas formed by the imaging optical systems that form the plurality of different images are separated without overlapping each other. 3. The multifocal imaging device according to claim 2, wherein imaging areas formed by the respective imaging optical systems that form the plurality of different images partially overlap each other. 5. The multifocal imaging device according to claim 1, further comprising means for shielding an optical path other than the selected imaging area in order to select any one of the plurality of imaging areas. Focus imaging device. 6. The multifocal imaging device according to claim 1, wherein any one of the imaging optical systems includes an imaging optical system different from the imaging optical system to which the optical element belongs. Multifocal imaging device modularized with optical elements. 7. The multifocal imaging device according to claim 6, wherein the object side surface of the plurality of image forming optical systems is a plane common to the image forming optical systems, and the image side surface is formed of each image forming optical system. A multifocal imaging device in which an outer-plane common optical element including a lens surface for an optical system is arranged. 8. The multifocal imaging device according to claim 7, wherein a part of optical paths of the plurality of imaging optical systems overlaps on a plane on the object side of the outer plane common optical element. 9. The multifocal imaging device according to claim 7 or 8, wherein a modularized intermediate optical element block having lens elements for each imaging optical system is disposed between the outer plane common optical element and the image sensor. Multifocal imaging device. 10. The multifocal imaging device according to claim 1, wherein the plurality of imaging optical systems are integrated with optical elements for the respective imaging optical systems that are located on the object side. A second lens module, which is located between the first lens module and the image sensor, in which the lens elements for each imaging optical system are integrated, and a plurality of imaging areas for a plurality of imaging optical systems. A multifocal imaging device comprising a single image sensor. 11. The multifocal imaging device according to claim 1, wherein each imaging optical system is different only in a relative position in an optical axis direction, and has the same optical surface shape, lens thickness, and optical material. A multifocal imaging device having at least one element. 12. The multifocal imaging device according to claim 1, wherein at least one of the plurality of imaging optical systems has a focal length different from that of another optical system. 13. The multifocal imaging device according to claim 12, wherein a focal length of an optical system having the longest focal length among the plurality of imaging optical systems is 1.5 times or more of a focal length of an optical system having the shortest focal length. A multifocal imaging device. 14. The multifocal imaging device according to claim 1, wherein at least one of the plurality of imaging optical systems has an object point at a distance equal to or less than 200 times the focal length. A multifocal imaging device that is set to focus only. 15. The multifocal imaging device according to any one of claims 1 to 14, wherein a single infrared cut filter for all the imaging areas is arranged in front of the plurality of imaging areas. device. 16. The multifocal imaging device according to any one of claims 1 to 15, wherein a single optical low-pass filter for all imaging areas is arranged in front of the plurality of imaging areas. . 17. The multifocal imaging device according to claim 1, wherein an optical path separation element that separates optical paths of the plurality of imaging optical systems is disposed between the imaging optical systems. A mobile device comprising the multifocal imaging device according to claim 1.

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