JP2017092679A - Electronic apparatus, optical element, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of capturing three-dimensional image data from which an excellent subject image is reproduced.SOLUTION: The imaging apparatus includes an imaging device 22. The imaging device comprises: an imaging device array 26 having an imaging plane on which a plurality of pixels 28 is arrayed in a matrix shape and in a two-dimensional shape; and a lenticular lens 25 which includes a plurality of cylindrical lenses 27, does not have refractive power in a second direction that crosses a first direction in which the plurality of pixels 28 is arrayed, at an angle larger than 0° and smaller than 90°, and is disposed at a front side of the imaging plane.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electronic device, an optical element, and an imaging element.

  Conventionally, a camera that receives incident light through a plurality of microlenses arranged in a two-dimensional manner is known (for example, Patent Document 1). When reproducing a captured image of such a camera, the resolving power in the vertical and horizontal directions is lower than when reproducing a captured image received without a microlens.

Special table 2008-515110 gazette

According to the first aspect of the present invention, the electronic device includes an imaging element having an imaging surface in which a plurality of pixels are arranged two-dimensionally, and a plurality of cylindrical lenses, and the plurality of pixels are arranged. A lenticular lens disposed on the imaging surface that does not have refractive power in a second direction intersecting the first direction at an angle greater than 0 degree and less than 90 degrees.
According to the second aspect of the present invention, the electronic apparatus has an imaging element having an imaging surface in which a plurality of pixels are arranged two-dimensionally, and a plurality of cylindrical lenses, and has a refractive power in a predetermined direction. A lenticular lens disposed on the imaging surface, and an optical member provided with an opening through which a part of the light passing through the optical system and going to the lenticular lens passes, the predetermined portion of the opening The width of the opening in the direction is smaller than the width of the opening in at least one of the other directions of the opening.
According to the third aspect of the present invention, the optical element is provided on a base material having two opposing surfaces, a plurality of cylindrical lenses provided on one of the two surfaces, and the other of the two surfaces. And a support portion made of a material having a thermal expansion coefficient equal to that of the material constituting the plurality of cylindrical lenses.
According to the fourth aspect of the present invention, the image pickup element is provided with the optical element of the third aspect on the image pickup surface.

The figure which shows typically the structure of the stereo image reproduction | regeneration system which concerns on 1st Embodiment. Sectional drawing which shows the structure of an imaging device typically Perspective view of image sensor Plan view of image sensor A diagram schematically showing the aperture viewed from the direction of the subject image Sectional view of AA cross section of image sensor The perspective view which shows the structure of a reproducing | regenerating apparatus typically Illustration of conversion process A diagram schematically showing the aperture viewed from the direction of the subject image

(First embodiment)
FIG. 1 is a diagram schematically illustrating a configuration of a stereoscopic image reproduction system according to the first embodiment. The stereoscopic image reproduction system 1 includes an imaging device (electronic device) 2 and a reproduction device 3. The imaging device 2 captures a three-dimensional subject image 4 and outputs three-dimensional image data 5. The reproduction device 3 reproduces a three-dimensional subject image 4x based on the three-dimensional image data 5. The observer 6 can observe the three-dimensional subject image 4x reproduced by the reproducing device 3.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the imaging device 2. The imaging device 2 includes an imaging optical system 21, a diaphragm 20, an imaging element 22, a control unit 23, and a display unit 24. The imaging optical system 21 condenses incident light toward the imaging element 22. The diaphragm 20 is provided with an opening through which a part of the light passing through the imaging optical system 21 toward the imaging surface of the imaging element 22 passes, and shields the remainder of the light. In FIG. 2, the diaphragm 20 is provided between a plurality of lenses constituting the imaging optical system 21, but the diaphragm 20 may be provided on the front side or the rear side of the imaging optical system 21. The image sensor 22 is an image sensor such as a CMOS or CCD. The configuration of the image sensor 22 will be described in detail later with reference to FIGS. The imaging element 22 outputs an imaging signal obtained by photoelectrically converting incident light.

  The control unit 23 controls each unit of the imaging device 2 including the imaging element 22. For example, the control unit 23 causes the image sensor 22 to photoelectrically convert incident light and causes the image sensor 22 to output an image signal. The control unit 23 creates three-dimensional image data of the subject image 4 by executing a conversion process described later on the imaging signal output from the imaging element 22. The control unit 23 records the created 3D image data on, for example, a recording medium (not shown) or transmits the data to the playback device 3 via a communication device (wired or wireless) (not shown). The display unit 24 is a display device having a display member such as a liquid crystal panel. The control unit 23 displays various setting screens on the display unit 24 and displays 3D image data on the display unit 24.

  FIG. 3 is a perspective view of the image sensor 22. The imaging element 22 includes a lenticular lens 25 and an imaging pixel array 26 provided on the rear side of the lenticular lens 25.

  The lenticular lens 25 is a lens array having a plurality of cylindrical lenses 27. The cylindrical lens 27 has a shape in which a cylinder is cut out by a plane parallel to the central axis. The cylindrical lens 27 is arranged so that the convex surface faces the subject image 4. In the following description, the width of the cylindrical lens 27 is expressed as a width w, and the focal length is expressed as a focal length f.

  The imaging pixel array 26 is disposed at a position away from the vertex of the convex surface of the lenticular lens 25 by a focal length f in the direction opposite to the subject image 4. That is, the distance from the apex of the convex surface of the cylindrical lens 27 to the imaging surface of the imaging pixel array 26 is equal to the focal length f. In FIG. 3, for the sake of convenience, the distance between the lenticular lens 25 and the imaging pixel array 26 is shown larger than the actual distance.

  On the imaging surface of the imaging pixel array 26, a plurality of imaging pixels 28 are squarely arranged in a two-dimensional manner along the x direction and the y direction. In the following description, the pitch of the imaging pixels 28 is denoted as pitch d.

  Subject light that has passed through one of the cylindrical lenses 27 is incident on each imaging pixel 28. A plurality of imaging pixels 28 correspond to one cylindrical lens 27. For example, the width w of the cylindrical lens 27 is configured to be about 10 times the pitch d of the imaging pixels 28.

  In FIG. 3, the cylindrical lens 27 and the imaging pixel 28 are shown exaggerated to be larger than actual. In practice, the individual cylindrical lenses 27 and the imaging pixels 28 are smaller than those shown in FIG. That is, the lenticular lens 25 has a larger number of cylindrical lenses 27, and the imaging pixel array 26 has a larger number of imaging pixels 28.

  FIG. 4 is a plan view of the image sensor 22. As described above, the cylindrical lens 27 has the width w. The center of the width w of the cylindrical lens 27 coincides with the vertex of the convex surface. In the direction v along the apex of the convex surface of the cylindrical lens 27, the cylindrical lens 27 does not have refractive power. In the following description, this direction v is referred to as the vertical direction v.

  The vertical direction v is neither parallel nor perpendicular to the y direction in which the imaging pixels 28 are arranged two-dimensionally. That is, the vertical direction v makes a predetermined angle θ with respect to the y direction. The angle θ is an angle larger than 0 degree and smaller than 90 degrees. The angle θ may be 0 degree.

  FIG. 5 is a diagram schematically showing the diaphragm 20 viewed from the direction of the subject image 4. The diaphragm 20 is provided with an opening 29. The opening 29 has a shape symmetrical with respect to a straight line s passing through the optical axis O of the imaging optical system 21. Specifically, it has a shape close to a rectangle defined by a pair of parallel lines L1 and L2 that are separated from the optical axis O by an equal distance. The straight line s forms the same angle θ as the vertical direction v shown in FIG. 4 with respect to the y direction in which the imaging pixels 28 are arranged two-dimensionally. That is, the straight line s is parallel to the vertical direction v. The opening width d1 of the opening 29 in the direction along the straight line s (vertical direction v) is smaller than the opening width d2 of the opening 29 in the direction orthogonal to the straight line s.

  The diaphragm 20 is configured to be able to change the size of the opening 29. For example, a pair of parallel lines L1 and L2 can be moved closer to or away from the straight line s by an actuator (not shown). Thereby, the opening width d1 of the opening 29 changes. The diaphragm 20 may be configured so that not only the opening width d1 but also the opening width d2 changes.

  If the subject image 4x (FIG. 1) to be reproduced is blurred in the vertical direction v (that is, the direction in which the cylindrical lens 27 does not have refractive power), the observer 6 feels uncomfortable. Therefore, in the vertical direction v, it is desirable to narrow down the diaphragm 20 to some extent to increase the depth of field. On the other hand, if the diaphragm 20 is narrowed in other directions, the resolution in the depth direction is reduced. Therefore, in the present embodiment, the imaging device 2 is provided with the diaphragm 20 shown in FIG. 5 in which the opening width of the opening 29 is different between the vertical direction v and the other direction.

  Note that the size of the opening 29 in the direction orthogonal to the vertical direction v is preferably determined based on the width w of the cylindrical lens 27. Specifically, when the F value determined from the opening width of the opening 29 in the direction orthogonal to the vertical direction v is compared with the F value determined from the width w of the cylindrical lens 27, the former does not become smaller than the latter. It is desirable to make it. If the former is smaller than the latter, the light passing through the adjacent cylindrical lenses 27 may enter one imaging pixel 28, which may hinder the reproduction of the subject image 4x.

  The size of the opening 29 in the vertical direction v is preferably determined according to the characteristics of the subject image 4. For example, when the subject image 4 has a pattern along the vertical direction v, it is desirable to make the size of the opening 29 in the vertical direction v smaller. A user who uses the imaging apparatus 2 may manually set the size of the opening 29 in the vertical direction v, or the control unit 23 analyzes the pattern of the subject image 4 to analyze the opening 29 in the vertical direction v. May be set automatically.

  6 is a cross-sectional view taken along the line AA of the image sensor 22 (FIG. 4). The lenticular lens 25 includes a plate-like base material (substrate) 252, a lens portion 251 formed on one surface of the base material 252, and a support portion 253 formed on the other surface of the base material 252. The base material 252 is made of glass, for example. The lens unit 251 and the support unit 253 are made of, for example, an ultraviolet curable resin (UV curable resin). The lenticular lens 25 is formed by, for example, the 2P method (Photoreplication Process). The lens unit 251 irradiates light containing ultraviolet rays (light of a predetermined wavelength band) after pouring UV curable resin into a mold for forming a lens shape or pressing the UV curable resin with a mold, for example. It is formed by doing.

  The lens portion 251 and the support portion 253 are made of the same material. That is, the thermal expansion coefficient of the material constituting the lens portion 251 and the thermal expansion coefficient of the material constituting the support portion 253 are equal. Therefore, when the lens unit 251 expands due to heat generated when light including ultraviolet rays is irradiated, the support unit 253 expands similarly.

  FIG. 7 is a perspective view schematically showing the configuration of the playback device 3. The reproducing device 3 includes a lenticular lens 35 and a display pixel array 36. The lenticular lens 35 is an optical element similar to the lenticular lens 25 included in the imaging device 2. That is, the lenticular lens 35 has a plurality of cylindrical lenses 37. The width w (FIG. 3) and the angle θ (FIG. 4) are the same as those of the lenticular lens 25.

  The display pixel array 36 is a display device such as a liquid crystal panel. The display pixel array 36 has a display surface on which a plurality of display pixels 38 are two-dimensionally arranged. The arrangement of the display pixels 38 is the same as the arrangement of the imaging pixels 28 in the imaging pixel array 26 included in the imaging device 2. In other words, the display pixel array 36 has a configuration in which the imaging pixel 28 in the imaging pixel array 26 is replaced with the display pixel 38.

  The principle of 3D image reproduction will be described with reference to FIG. Attention is paid to one light spot LP among the many light spots constituting the subject image 4. The light from the light spot LP is incident on the lenticular lens 25 with a certain spread, and is incident on the imaging pixels 28a, 28b, 28c, 28d, and 28e according to the direction from the light spot LP by the cylindrical lens 27. The imaging pixels 28a, 28b, 28c, 28d, and 28e each photoelectrically convert incident light and output a photoelectric conversion signal.

  As shown in FIG. 7, the reproducing device 3 includes a display pixel array 36 having a plurality of display pixels 38. The positional relationship between the lenticular lens 35 and the display pixel array 36 is the same as the positional relationship between the lenticular lens 25 and the imaging pixel array 26 shown in FIG. Accordingly, when an image captured by the image sensor 22 is displayed on the display pixel array 36, the light from the plurality of display pixels 38 is directed to the observer 6 in the direction opposite to the content described above. That is, light from different display pixels 38 corresponding to the imaging pixels 28 a, 28 b, 28 c, 28 d, and 28 e forms one light spot LP by the cylindrical lens 37. As described above, the three-dimensional subject image 4x imaged by the imaging device 2 is reproduced by the reproduction device 3.

  The above reproduction principle does not take into account the difference between the imaging direction and the observation direction, so that there is a problem that the depth is reversed. For example, when an image picked up by the image pickup device 22 is displayed as it is on the display pixel array 36, a light spot close to the image pickup device 2 is reproduced at a position close to the reproduction device 3, and a light spot far from the image pickup device 2 is reproduced. It is reproduced at a position far from the device 3. However, considering the viewpoint of the observer 6 as a reference, the light spot close to the imaging device 2 is reproduced at a position far from the observer 6, and the light spot far from the imaging apparatus 2 is reproduced at a position near the observer 6. Will end up. Therefore, in the present embodiment, the control unit 23 executes a conversion process described below. In the conversion process, the control unit 23 creates the three-dimensional image data 5 by reversing the depth of the image captured by the image sensor 22. Therefore, when the reproduction device 3 reproduces the subject image 4x based on the three-dimensional image data 5, the observer 6 can observe the subject image 4x with a correct depth.

  FIG. 8 is an explanatory diagram of the conversion process. Now, a direction h orthogonal to the vertical direction v is considered. In the following description, the direction h is referred to as the horizontal direction h. Consider one straight line parallel to the horizontal direction h. The control unit 23 reverses the output of the imaging pixel group 280 covered by one cylindrical lens 27 along the straight line. For example, the imaging pixel group 280 including the nine imaging pixels 28 illustrated in FIG. 8 is arranged along one straight line parallel to the horizontal direction h among the imaging pixels 28 covered by a certain cylindrical lens 27. A collection of imaging pixels 28. The control unit 23 converts the imaging signal output by each imaging pixel 28 constituting the imaging pixel group 280 so as to be reversed along the horizontal direction h. For example, the imaging signal output from the imaging pixel 28l illustrated in FIG. 8 is replaced with the imaging signal output from the imaging pixel 28r. The control unit 23 creates the three-dimensional image data 5 with the depth reversed by appropriately executing the above processing on the imaging signal while changing the position of the straight line little by little for all the cylindrical lenses 27. .

According to the embodiment described above, the following operational effects can be obtained.
(1) A lenticular lens 25 having a plurality of cylindrical lenses 27 is disposed on the light receiving surface (imaging surface) of the imaging pixel array 26. The plurality of imaging pixels 28 are arranged along the x direction and the y direction, and the lenticular lens 25 does not have refractive power in the vertical direction v, and the x direction and the vertical direction v, and the y direction and the vertical direction v are any. Also, a predetermined angle larger than 0 degree and smaller than 90 degrees is made. Since it did in this way, the three-dimensional image data which can reproduce a high-definition three-dimensional image with which a moire and a sub pixel are hard to be observed can be imaged. Further, the resolving power along the vertical direction v of the subject image when reproducing the captured image obtained by capturing the subject image having a pattern along the vertical direction v of the lenticular lens 25 reproduces the captured image received without the lenticular lens 25. It does not drop compared to the case of doing.

(2) The control unit 23 converts the image signal output from the image sensor 22 into 3D image data 5 in which the depth of the subject image 4 is reversed. Since it did in this way, the three-dimensional to-be-photographed image 4x which the observer 6 does not feel discomfort can be reproduced | regenerated.

(3) The lenticular lens 25 is provided on the base 252 having two opposing surfaces, a lens portion 251 including a plurality of cylindrical lenses 27 provided on one of the two surfaces, and on the other of the two surfaces. A support portion 253. The thermal expansion coefficient of the material constituting the plurality of cylindrical lenses 27 is equal to the thermal expansion coefficient of the material constituting the support portion 253. Since it did in this way, even if it is a case where the some cylindrical lens 27 expand | swells with heat or it loses heat and shrinks, the lenticular lens 25 maintains the original shape as a whole, and can suppress curvature and a bending. it can.

(4) The aperture 20 is provided with an opening 29 through which a part of the light passing through the imaging optical system 21 and going to the lenticular lens 25 passes. The opening 29 has a shape symmetrical with respect to a straight line s passing through the optical axis O of the imaging optical system 21, and the straight line s is parallel to the vertical direction v. The width d1 of the opening 29 in the vertical direction v of the opening 29 is smaller than the width d2 of the opening in the other direction of the opening 29. Since it did in this way, in the reproduced three-dimensional subject image 4x, it is possible to achieve both low blur and resolution in the depth direction.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
A functional unit different from the control unit 23 may execute the conversion process described above. For example, a conversion device that receives an imaging signal from the imaging device 2 and executes conversion processing to create the three-dimensional image data 5 may be provided separately from the imaging device 2 and the playback device 3. Alternatively, the playback device 3 may receive the imaging signal from the imaging device 2 and execute a conversion process to create the 3D image data 5. Further, the 3D image data 5 may be created by causing a computer provided separately from the imaging device 2 and the playback device 3 to execute a program including conversion processing.

(Modification 2)
The conversion process for reversing the depth may be omitted. Even in this case, the reproducing apparatus 3 can reproduce the three-dimensional subject image 4x. Instead of executing the conversion process, a reflection optical system may be added to the reproducing apparatus 3 so that the observer 6 can observe the subject image 4x whose depth is reversed.

(Modification 3)
The display unit 24 of the imaging device 2 may include a lenticular lens 35 and a display pixel array 36 as in the case of the playback device 3 described above. By doing in this way, the user of the imaging device 2 can simply confirm the captured three-dimensional subject image 4 and the usability of the imaging device 2 is improved.

(Modification 4)
The lenticular lens 25 of the imaging device 2 and the lenticular lens 35 of the reproducing device 3 do not necessarily have the same configuration. For example, the widths w may be different from each other. In this case, the ratio between the pitch d of the imaging pixels 28 and the pitch d of the display pixels 38 is desirably equal to the ratio between the width w of the lenticular lens 25 and the width w of the lenticular lens 35. In addition, the angle θ of the lenticular lens 25 of the imaging device 2 and the angle θ of the lenticular lens 35 of the reproducing device 3 do not have to be strictly coincident with each other, and do not deteriorate the quality of the reproduced subject image 4x. I do it.

(Modification 5)
The shape of the opening 29 is not limited to that shown in FIG. FIG. 9 shows diaphragms 20a and 20b having openings of other shapes. The diaphragm 20a shown in FIG. 9 has an elliptical opening 29a. The diaphragm 20b has a semicircular opening 29b. However, the present invention is not limited thereto, and an opening 29 having an arbitrary shape that is line-symmetric with respect to the straight line s can be provided.

Note that the electronic apparatus according to the present embodiment is not limited to the imaging apparatus (electronic apparatus) 2 as described above. For example, the present embodiment can be applied to a lens-integrated digital still camera or a video camera. Furthermore, the present embodiment can also be applied to a small camera module built in an electronic device such as a mobile phone, a smart phone, and a tablet PC, a surveillance camera, a visual recognition device for a robot, an in-vehicle camera, and the like.
Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Stereoscopic image reproduction system, 2 ... Imaging device, 3 ... Reproduction device, 22 ... Imaging device, 23 ... Control part, 25, 35 ... Lenticular lens, 26 ... Imaging pixel array, 27, 37 ... Cylindrical lens, 28 ... Imaging Pixel, 36 ... display pixel array, 38 ... display pixel

Claims (8)

An imaging device having an imaging surface in which a plurality of pixels are arranged two-dimensionally;
The imaging surface having a plurality of cylindrical lenses and having no refractive power in a second direction intersecting with a first direction in which the plurality of pixels are arranged at an angle larger than 0 degree and smaller than 90 degrees An electronic device comprising a lenticular lens disposed on the surface. The electronic device according to claim 1,
The plurality of pixels are arranged two-dimensionally in a matrix,
The electronic device in which the first direction is a column direction of the matrix. The electronic device according to claim 1 or 2,
An electronic apparatus further comprising a conversion unit that converts an imaging signal output by the imaging element into a signal in which the unevenness of a subject image is inverted. In the electronic device as described in any one of Claims 1-3,
The lenticular lens includes a substrate having two opposing surfaces, a plurality of cylindrical lenses provided on one of the two surfaces, and a support provided on the other of the two surfaces,
An electronic apparatus in which a coefficient of thermal expansion of a material constituting the plurality of cylindrical lenses is equal to a coefficient of thermal expansion of a material constituting the support portion. In the electronic device as described in any one of Claims 1-4,
An optical member provided with an opening through which a part of the light passing through the optical system and going to the lenticular lens passes,
An electronic device in which the width of the opening in the second direction of the opening is smaller than the width of the opening in at least one of the other directions of the opening. An imaging device having an imaging surface in which a plurality of pixels are arranged two-dimensionally;
A plurality of cylindrical lenses having no refractive power in a predetermined direction, and a lenticular lens disposed on the imaging surface;
An optical member provided with an opening through which a part of the light passing through the optical system and going to the lenticular lens passes,
An electronic device in which the width of the opening in the predetermined direction of the opening is smaller than the width of the opening in at least one of the other directions of the opening. A base material having two opposing surfaces, a plurality of cylindrical lenses provided on one of the two surfaces, and a coefficient of thermal expansion of a material provided on the other of the two surfaces and constituting the plurality of cylindrical lenses A support made of a material having a coefficient of thermal expansion equal to
An optical element comprising:   An imaging device comprising the optical device according to claim 7 provided on an imaging surface.

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