JP2014036298A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To image images having the same size and being in two directions, without adjusting the optical conditions of an optical system and to suppress the increase of the size of an apparatus.SOLUTION: A polarization device includes a first polarizing plate and a second polarizing plate. In the first polarizing plate, a polarizer layer is formed and the first polarizing plate reflects image light having one polarization component having one of polarization directions orthogonal to each other and transmits image light having the other polarization component. In the second polarizing plate, the polarizer layer is formed and the second polarizing plate transmits the image light having one polarization component having one of the polarization directions orthogonal to each other and reflects the image light having the other polarization component. The first polarizing plate and the second polarizing plate are provided so that an angle formed by the first polarizing plate and the second polarizing plate is a predetermined angle. The polarization component of the image light reflected by the first polarizing plate and transmitted through the second polarizing plate and the polarization component of the image light transmitted through the first polarizing plate and reflected by the second polarizing plate have the polarization directions orthogonal to each other.

Description

  The present invention relates to an imaging apparatus that captures images in two directions or images in the same direction.

  As this type of imaging apparatus, the one of Patent Document 1 is known. In the imaging apparatus disclosed in Patent Document 1, the first image light that is incident from one direction through the condenser lens and reflected from the reflecting mirror is incident from the other direction different from the one direction through the condenser lens. The second image light is guided to a polarization beam splitter (polarization device). The polarizing beam splitter includes one polarizing plate. On one surface of the polarizing plate, light of one polarization component is transmitted through the light incident on the surface of the two polarization components having the polarization directions orthogonal to each other. On the other surface of the polarizing plate, the light of the other polarization component is reflected among the light of the two polarization components having the polarization directions orthogonal to each other. When the first image light is incident on one surface of the polarizing plate of the polarization beam splitter, the image light of one polarization component of the two polarization components having the polarization directions orthogonal to each other in the first image light. Is transmitted to the other surface side of the polarizing plate. When the second image light is incident on the other surface of the polarizing plate in the polarizing beam splitter, the image light of the other polarization component of the second image light is reflected. To do. Then, the image light of one polarization component in the first image light and the image light of the other polarization component in the second image light are guided to the image sensor side that is in the same direction.

  An area division filter (optical polarization filter) is provided between the polarization beam splitter and the image sensor. The region dividing filter includes: a first region that transmits light of one polarization component, and a second region that transmits light of the other polarization component, out of two polarization components having polarization directions whose polarization directions are orthogonal to each other. Is formed in a strip shape, and a plurality of first regions and second regions are alternately arranged. The image light of one polarization component in the first image light and the image light of the other polarization component in the second image light are incident on the region dividing filter. In the area dividing filter, the image light incident from the polarizing device is separated into image light of one polarization component in the first image light through each first region, and the second light is transmitted through each second region. It separates into image light of the other polarization component in the image light. The separated image light of the two polarization components forms an image on all imaging regions of the imaging device. The image sensor outputs a photoelectrically converted image signal. Thereby, each image of the 1st image light and the 2nd image light which were image-processed based on the image signal is displayed on one screen on a monitor.

  However, in the imaging apparatus of Patent Document 1, the first image light collected by the condenser lens is guided to the polarization beam splitter through the reflection mirror, while the second image light condensed by the condenser lens is polarized. It leads directly to the beam splitter. Therefore, the first optical path length, which is the length of the optical path while the first image light reaches the polarization beam splitter, is equal to the optical path length of the first image light through the reflection mirror, and the second image light is the polarization beam splitter. Is longer than the second optical path length, which is the length of the optical path while arriving at. For example, the image light obtained by capturing an image in one direction in the imaging device as the left direction of the imaging device is used as the first image light, and the image in that direction is captured in the other direction in the imaging device as the right direction of the imaging device. The image light is the second image light. At this time, even if the object in the left direction from the imaging device and the object in the right direction from the imaging device have the same size and the same distance from the imaging device to each object, the left and right directions The sizes of the objects on the monitor screen that displays the image are different from each other. When the imaging apparatus is mounted on a vehicle as in Patent Document 1, the left and right images displayed on the monitor are different in size, resulting in images with different perspectives. For example, when the vehicle is approximately the same distance from the left and right, there is a possibility that the driver determines that the left image is close and that the right image is far away. Therefore, in order to make the sizes of the objects on the monitor screen the same, the optical conditions of the optical system had to be adjusted. Specifically, the positions of a plurality of lenses constituting the optical system are adjusted, and the lens power is adjusted. These adjustments require considerable technology and time, and are complicated. And since the whole apparatus must be comprised according to the 1st optical path length with a long optical path length, the enlargement of an apparatus will be caused.

  The present invention has been made in view of the above problems, and the objects thereof are as follows. It is an object of the present invention to provide an imaging apparatus capable of capturing images in two directions having the same size without adjusting the optical conditions of the optical system and suppressing the increase in size of the apparatus.

  In order to achieve the above object, the invention of claim 1 includes a polarizing device, an optical polarizing filter, and an imaging device, and the optical polarizing filter is provided between the polarizing device and the imaging device, and is polarized. A first region that transmits image light of one polarization component having one polarization direction among the polarization directions orthogonal to each other, and the other polarization component having the other polarization direction among the polarization directions orthogonal to each other. A plurality of second regions that transmit the image light of the first image light, and the polarization device captures the image light of one polarization component in the first image light captured from one of the two directions and the other direction. The image light of the other polarization component in the second image light is combined and polarized into one image light, and the optical polarization filter converts the image light incident from the polarization device into each first region. To separate the image light of one polarization component in the first image light and to the image light of the other polarization component in the second image light by passing through each second region, the two separated polarization components In the imaging device which photoelectrically converts the image light of the image by the imaging device and outputs an image signal, the polarizing device includes a first polarizing plate and a second polarizing plate, and the first polarizing plate is formed by a polarizer layer. And the image light of one polarization component having one polarization direction out of the polarization directions perpendicular to each other is reflected and the image light of the other polarization component is transmitted, and the second polarizing plate is a polarizer layer And the image light of one polarization component having one polarization direction among the polarization directions orthogonal to each other is transmitted and the image light of the other polarization component is reflected, and the first polarizing plate and the first polarization 2 polarizing plates The first polarizing plate and the second polarizing plate are provided so that a predetermined angle is a predetermined angle, and the polarization component of the image light transmitted through the first polarizing plate and the second polarizing plate are transmitted. The polarization components of the image light reflected by the first polarizing plate have polarization directions orthogonal to each other, and pass through the second polarizing plate and the polarization component of the image light that passes through the first polarizing plate, and then pass through the second polarizing plate. The polarization component of the image light reflected by the polarizing plate has a polarization direction orthogonal to each other.

  In the present invention, the first polarizing plate of the polarizing device reflects the image light of one polarization component having one polarization direction out of the polarization directions whose polarization directions are orthogonal to each other and transmits the image light of the other polarization component. On the other hand, the second polarizing plate of the polarizing device transmits the image light of one polarization component having one polarization direction among the polarization directions whose polarization directions are orthogonal to each other, and reflects the image light of the other polarization component. The first polarizing plate and the second polarizing plate are provided so as to form a predetermined angle. As a result, the image light of one polarization component incident from the back surface of the first polarizing plate and transmitted through the first polarizing plate enters from the back surface of the second polarizing plate, passes through the second polarizing plate, and passes through the first polarizing plate. It becomes one image light together with the image light of the other polarization component reflected by the plate. Then, the image light is emitted to the side where the first polarizing plate and the second polarizing plate face each other. The image light of the other polarization component incident from the back surface of the second polarizing plate and transmitted through the second polarizing plate is incident from the back surface of the first polarizing plate, passes through the first polarizing plate, and is reflected by the second polarizing plate. It becomes one image light together with the image light of one polarization component. Then, the image light is also emitted to the side where the first polarizing plate and the second polarizing plate face each other.

  Since the image light incident from the back surface of the first polarizing plate and the image light incident from the back surface of the second polarizing plate are reflected and transmitted by the polarizing device in substantially the same manner, the optical path length is the same. is there. The two polarization component image lights having different polarization directions emitted from the polarization device are separated into two polarization component image lights having polarization directions orthogonal to each other by the optical polarization filter. The sizes of the two images on the screen of the monitor generated based on the image signal after photoelectric conversion by the image sensor are displayed in substantially the same manner. Therefore, it is possible to capture images in two directions having the same size without adjusting the optical conditions of the optical system. In addition, since the optical path lengths of the image light captured from the back surface of the first polarizing plate and the image light captured from the back surface of the second polarizing plate are substantially the same, an increase in size of the apparatus can be suppressed.

It is the schematic which shows the structure of the imaging device of this embodiment. It is a figure which shows a response | compatibility of the positional relationship of an optical polarization filter and an image pick-up element. FIG. 3 is a cross-sectional view of FIG. 2. It is the schematic which shows the structure of Example 1 of the polarizing device in the imaging device which concerns on this embodiment. It is the schematic which shows the structure of Example 2 of the polarizing device in the imaging device which concerns on this embodiment. It is a schematic plan view which shows the optical path of the light which injects into Example 2 of a polarizing device. It is a schematic perspective view which shows the structure of Example 3 of a polarizing device. It is a schematic plan view which shows the optical path of the light which injects into Example 3 of a polarizing device. It is a schematic plan view which shows the optical path of the light which injects into Example 3 of a polarizing device. It is the schematic which shows the structure of a part of Example 1 of an imaging device. 1 is a schematic diagram illustrating an overall configuration of Embodiment 1 of an imaging apparatus. It is a schematic plan view which shows the mode of an imaging when Example 1 of an imaging device is mounted in a vehicle. It is a figure which shows the example of an image | video of a monitor apparatus. It is the schematic which shows the partial structure of Example 2 of an imaging device. It is the schematic which shows the whole structure of Example 2 of an imaging device. It is the schematic which shows the structure which mounts Example 2 of an imaging device in the vehicle. It is the schematic which shows a partial structure of Example 3 of an imaging device. It is the schematic which shows the whole structure of Example 3 of an imaging device. It is the schematic which shows a partial structure of Example 4 of an imaging device. It is the schematic which shows the whole structure of Example 4 of an imaging device. It is the schematic which shows the whole structure of Example 5 of an imaging device. It is a top view of a to-be-inspected object. It is a figure which shows the test | inspection image by Example 5 of an imaging device. It is the schematic which shows a partial structure of Example 6 of an imaging device. It is the schematic which shows the whole structure of Example 6 of an imaging device. It is the schematic which shows the structure which mounted Example 6 of the imaging device on the vehicle. It is the schematic which shows a partial structure of Example 7 of an imaging device. It is the schematic which shows the whole structure of Example 7 of an imaging device. It is the schematic which shows the partial structure of Example 8 of an imaging device. It is the schematic which shows the whole structure of Example 8 of an imaging device. It is the schematic which shows the structure which mounted Example 8 of the imaging device in the vehicle.

Hereinafter, an embodiment of an imaging apparatus according to the present invention will be described.
FIG. 1 is a schematic diagram illustrating a configuration of an imaging apparatus according to the present embodiment. In the present embodiment, the imaging apparatus 100 is arranged so that the optical axis of the imaging lens 104 is oriented in the horizontal direction, but the present invention is not limited to this. The imaging apparatus 100 includes a substrate 101, an imaging element 102, an optical polarization filter 103, and an imaging lens 104. Further, a polarization selection type cross prism 105 and a signal processing unit 106, which are examples of a polarization device described later, are provided in the front stage of the imaging lens 104. The image sensor 102 is mounted on the substrate 101. It is composed of a plurality of two-dimensionally arranged pixels that receive light transmitted through the optical polarization filter 103, and has a function of photoelectrically converting incident light for each pixel. Although each pixel of the image sensor 102 in FIG. 2 is illustrated in a simplified manner, in actuality, the image sensor 102 is configured by about several hundred thousand pixels arranged two-dimensionally. As the image sensor 102, for example, a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), or the like can be used. The optical polarization filter 103 is disposed at the subsequent stage of the imaging lens 104 and has a function of selectively transmitting a polarization component of light incident on the imaging element 102.

  The signal processing unit 106 generates and outputs captured image data obtained by converting an analog electrical signal (incident light amount to each pixel of the image sensor 102) that is photoelectrically converted by the image sensor 102 and output from the substrate 101 into a digital electrical signal. It has the function to do. The signal processing unit 106 is electrically connected to the image analysis unit 120. An electric signal (analog signal) is input from the image sensor 102 to the signal processing unit 106 via the substrate 101. The signal processing unit 106 generates a digital signal (captured image data) indicating the brightness (luminance) of each pixel on the image sensor 102 as captured image data from the input electrical signal, along with the horizontal / vertical synchronization signal of the image. Output to the image analysis unit 120. The image analysis unit 120 performs image processing based on an output signal from the imaging device in a vehicle mounting example described later, and is used for warning or vehicle control.

Next, the polarization separation SWS filter will be described.
FIG. 2 is a diagram showing the correspondence of the positional relationship between the optical polarization filter and the image sensor. FIG. 3 is a cross-sectional view of FIG. In the optical polarization filter 103, the filter substrate 103-1 is a transparent substrate that transmits incident light incident on the optical polarization filter 103 via the imaging lens 104 of FIG. A polarizing filter layer 103-2 is formed on the surface of the filter substrate 103-1 on the image sensor 102 side. A filling layer 103-3 is further formed so as to cover the polarizing filter layer 103-2. Of the light incident on the optical polarization filter 103, the light transmitted through the polarization filter layer 103-2 is incident on the pixel region of the image sensor 102. Polarizers corresponding to the pixel size of the image sensor 102 are formed in the polarizing filter layer 103-2 in a region-divided manner. As the polarizer, an S-polarized component transmission region and a P-polarized component transmission region are formed. In FIG. 3, the S-polarized component transmission region and the P-polarized component transmission region may be strip-shaped patterns. Here, a monochrome sensor is assumed as the image sensor, but the image sensor is not limited to this and may be a color sensor. In the region where the polarizing filter layer 103-2 is formed, images of the P-polarized component and S-polarized component regions are taken, and these are used for various information detection as a parallax image by forming a differential image as will be described later. used.

  FIG. 4 is a schematic diagram illustrating the configuration of the first example of the polarization device in the imaging apparatus according to the present embodiment. 4A is a schematic plan view, and FIG. 4B is a schematic perspective view. A polarizing device 200 shown in FIG. 4 includes at least two polarizing plates. The first polarizing plate 201 has a polarization plane in which, for example, a polarizer layer having a wire grid structure is provided on the surface of a flat substrate. The second polarizing plate 202 is disposed so that the edge of the second polarizing plate 202 abuts the edge of the first polarizing plate 201 and forms a predetermined angle θ, for example, a substantially right angle as shown in FIG. Yes. The 1st polarizing plate 201 and the 2nd polarizing plate 202 have the polarizing surfaces 201-1 and 202-1 which provided the polarizer layer of the wire grid structure, for example on the surface of a plane substrate. The polarizing plane 201-1 of the first polarizing plate 201 and the polarizing plane 202-1 of the second polarizing plate 202 are opposed to each other. The polarization directions in the wire grid structure of the first polarizing plate 201 and the second polarizing plate 202 are orthogonal to each other. Since the first polarizing plate 201 and the second polarizing plate 202 have no plate aberration, the light incident on each polarizing plate travels to the target optical path.

Next, the optical path of light incident on the polarizing device of Example 1 will be described.
In the light incident on the side surface 211 of the polarizing device 200 shown in FIG. 4A, the optical path is branched into the + Y direction and the −Y direction according to the polarization direction. In the optical path I1 of the light incident on the side surface 211 of the polarization device 200, the light in the polarization direction in the Y-axis direction (hereinafter, the polarization component in the direction parallel to the paper surface is called the P polarization component) is the polarizer layer of the first polarizing plate 201. Reflected by (not shown). Then, the light passes through a polarizer layer (not shown) of the second polarizing plate 202 and proceeds in the −Y direction. On the other hand, in the optical path I1 of the light incident on the side surface 211 in the polarizing device 200, the light in the polarization direction in the Z-axis direction (hereinafter, the polarization component in the vertical direction in the drawing is called the S polarization component) is polarized by the first polarizing plate 201. The light passes through the child layer (not shown), is reflected by the reflecting plate 203, and proceeds in the + Y direction. In the optical path I2 incident on the side surface 211 of the polarizing device 200, the light of the S polarization component is reflected by the polarizer layer (not shown) of the second polarizing plate 202 and passes through the polarizer layer (not shown) of the first polarizing plate 201. Transmits and proceeds in the + Y direction. On the other hand, in the optical path I2 incident on the side surface 211 of the polarizing device 200, the P-polarized component light passes through the polarizer layer (not shown) of the second polarizing plate 202, is reflected by the reflecting plate 204, and travels in the -Y direction.

  FIG. 5 is a schematic diagram illustrating the configuration of a second example of the polarization device in the imaging apparatus according to the present embodiment. FIG. 5A is a front view, and FIG. 5B is a perspective view. The polarizing device 200 shown in FIG. 5 is disposed so as to make a predetermined angle, for example, a substantially right angle as shown in FIG. 5, by abutting against the first polarizing plates 201 and 205 and the edge portions of the first polarizing plates 201 and 205. And at least the second polarizing plates 202 and 206. The polarizing plane of the first polarizing plate 201 and the polarizing plane of the second polarizing plate 202 are opposed to each other, and the polarizing plane of the first polarizing plate 205 and the polarizing plane of the second polarizing plate 206 are opposed to each other. For example, a polarizer layer having a wire grid structure is provided on each of the polarization planes of the first polarizing plates 201 and 205 and the second polarizing plates 202 and 206. The polarization directions in the wire grid structure of the first polarizing plate 201 and the second polarizing plate 202 are orthogonal to each other. The polarization directions in the wire grid structure of the first polarizing plate 205 and the second polarizing plate 206 are orthogonal to each other. Since the first polarizing plates 201 and 205 and the second polarizing plates 202 and 206 have no plate aberration, the light incident on each polarizing plate travels to the target optical path.

Next, the optical path of light incident on the polarizing device of FIGS. 5 and 6 will be described.
First, in FIG. 5, the light incident on the side surface 211 of the polarizing device 200 has its optical path branched into the + Y direction and the −Y direction according to the polarization direction. In the optical path I1 of light incident on the side surface 211 of the polarizing device 200, the light of the P-polarized component is reflected by the polarizer layer (not shown) of the first polarizing plate 201, and the polarizer layer (not shown) of the second polarizing plate 202. ) And proceed in the -Y direction. On the other hand, in the optical path I1 of the light incident on the side surface 211 in the polarizing device 200, the light of the S-polarized component is transmitted through the polarizer layer (not shown) of the first polarizing plate 201 and the polarizer layer ( (Not shown) and reflected in the + Y direction. The light of the S polarization component of the optical path I2 incident on the side surface 211 of the polarizing device 200 is reflected by the polarizer layer (not shown) of the second polarizing plate 202 and passes through the polarizer layer (not shown) of the first polarizing plate 201. Transmits and proceeds in the + Y direction. On the other hand, in the optical path I2 incident on the side surface 211 of the polarizing device 200, the P-polarized component light is transmitted through the polarizer layer (not shown) of the second polarizing plate 202, and the polarizer layer (not shown) of the first polarizing plate 205. ) And proceed in the -Y direction.

  In FIG. 6, the light incident on the side surface 212 of the polarizing device 200 has its optical path branched into the + Y direction and the −Y direction according to the polarization direction. In the optical path I3 incident on the side surface 212 of the polarizing device 200, the light of the S polarization component is reflected by the second polarizing plate 206, passes through the first polarizing plate 205, and travels in the −Y direction. On the other hand, in the optical path I3 incident on the side surface 212 of the polarizing device 200, the P-polarized component light passes through the second polarizing plate 206, is reflected by the first polarizing plate 201, and travels in the + Y direction. In the optical path I4 incident on the side surface 212 of the polarizing device 200, the P-polarized component light is reflected by the first polarizing plate 205, passes through the second polarizing plate 206, and travels in the + Y direction. On the other hand, in the optical path I4 incident on the side surface 212 of the polarizing device 200, the light of the S polarization component is transmitted through the first polarizing plate 205, reflected by the second polarizing plate 202, and travels in the −Y direction.

  FIG. 7 is a schematic perspective view showing the configuration of the third embodiment of the polarizing device. FIG. 8 is a schematic plan view showing an optical path of light incident on the third embodiment of the polarizing device. As shown in FIG. 7, the cross prism 10 has triangular prisms 1, 2, 3, 4 arranged so that apex angles 14, 24, 34, 44 of triangular prisms 1, 2, 3, 4 face each other and face each other. They are bonded together and bonded together. And the polarizing plate of the wire grid structure mentioned above is pinched | interposed between the triangular prisms 1, 2, 3, and 4 which oppose. By providing a triangular prism as in this embodiment, the plate aberration of the polarizing plate can be reduced.

  And as shown in FIG. 8, the planar shape of the cross prism 10 is substantially square. The cross prism 10 includes four triangular prisms 1, 2, 3, 4 having substantially right isosceles triangular prisms made of glass or the like, polarizing plates 5, 6, 7, 8 having a wire grid structure, and an adhesive layer 9. Yes. An adhesive layer 9 made of an adhesive and polarizing plates 5, 6, 7, and 8 are formed in gaps where the four triangular prisms 1, 2, 3, 4 face each other.

  The triangular prism 1 has three side surfaces 11, 12, 13, an apex angle 14 at which the side surfaces 12, 13 intersect at a substantially right angle, and is formed into a substantially right isosceles triangular prism. The triangular prism 2 has three side surfaces 21, 22, 23, an apex angle 24 at which the side surfaces 22, 23 intersect at a substantially right angle, and is formed into a substantially right isosceles triangular prism. The triangular prism 3 has three side surfaces 31, 32, 33, an apex angle 34 at which the side surfaces 32, 33 intersect at a substantially right angle, and is formed into a substantially right isosceles triangular prism. The triangular prism 4 has three side surfaces 41, 42, 43, an apex angle 44 at which the side surfaces 42, 43 intersect at a substantially right angle, and is formed into a substantially right isosceles triangular prism. The triangular prisms 1, 2, 3, and 4 are arranged such that the apex angles 14, 24, 34, and 44 abut each other.

  In the polarizing plate 5, a polarizer layer 52 is formed on a flat substrate 51, and the polarizer layer 52 is covered with a filling layer (not shown). Then, with respect to the light traveling from the ± X direction in the figure, the light having the polarization direction in the Y direction is reflected, and the light having the polarization direction in the Z direction is transmitted. In the polarizing plate 6, a polarizer layer 62 is formed on a flat substrate 61, and the polarizer layer 62 is covered with a filling layer (not shown). And the light which has a polarization direction in a Y direction permeate | transmits with respect to the light which progresses from +/- X direction in a figure, and the light which has a polarization direction in a Z direction reflects. In the polarizing plate 7, a polarizer layer 72 is formed on a flat substrate 71, and the polarizer layer 72 is covered with a filling layer (not shown). Then, with respect to the light traveling from the ± X direction in the figure, the light having the polarization direction in the Y direction is reflected, and the light having the polarization direction in the Z direction is transmitted. In the polarizing plate 8, a polarizer layer 82 is formed on a flat substrate 81, and the polarizer layer 82 is covered with a filling layer (not shown). And the light which has a polarization direction in a Y direction permeate | transmits with respect to the light which progresses from +/- X direction in a figure, and the light which has a polarization direction in a Z direction reflects.

  Further, the polarizing plate 5 is arranged with the polarizer layer 52 side facing the side surface 23 side of the triangular prism 2 with respect to the flat substrate 51. The filling layer surface (not shown) and the side surface 23 are bonded with an adhesive. The polarizing plate 6 is disposed with the polarizer layer 62 side facing the side surface 26 side of the triangular prism 2 with respect to the flat substrate 61. The filling layer surface (not shown) and the side surface 22 are bonded with an adhesive. The polarizing plate 7 is arranged with the polarizer layer 72 side facing the side surface 43 side of the triangular prism 4 with respect to the flat substrate 71. The filling layer surface (not shown) and the side surface 43 are bonded with an adhesive. The polarizing plate 8 is arranged with the polarizer layer 82 side facing the side surface 42 side of the triangular prism 4 with respect to the flat substrate 81. The filling layer surface (not shown) and the side surface 42 are bonded with an adhesive.

  The plane substrate 51 and the side surface 12 of the triangular prism 1 are joined with an adhesive. The flat substrate 61 and the side surface 33 of the triangular prism 3 are joined with an adhesive. The planar substrate 71 and the side surface 32 of the triangular prism 3 are joined with an adhesive. The flat substrate 81 and the side surface 13 of the triangular prism 1 are joined with an adhesive.

  The adhesive layer 9 is formed in a gap separating the triangular prisms 1, 2, 3, 4 and the polarizing plates 5, 6, 7, 8. The adhesive layer 9 is formed by performing a curing process of the adhesive in a lump, and adheres and fixes four triangular prisms and four polarizing plates. As this adhesive, an adhesive having good translucency, glass adhesion, and precision, such as an ultraviolet curable adhesive, is used.

Next, the optical path of light incident on the cross prism will be described with reference to FIGS.
As shown in FIG. 8, the light incident from the side surface 41 of the triangular prism 4 is branched in the + Y direction and the −Y direction according to the polarization direction. In the optical path I 1 of light incident on the side surface 41 of the triangular prism 4, the P-polarized component light in the polarization direction in the Y-axis direction is reflected by the polarizer layer 72 of the polarizing plate 7 and transmitted by the polarizer layer 82 of the polarizing plate 8. Then proceed in the -Y direction. On the other hand, in the optical path I 1 of light incident on the side surface 41 of the triangular prism 4, the light of the S polarization component in the polarization direction in the Z-axis direction is transmitted through the polarizer layer 72 of the polarizing plate 7 and the polarizer layer of the polarizing plate 6. Reflected at 62 and proceeds in the + Y direction. In the optical path I2 incident on the side surface 41 of the triangular prism 4, the S-polarized component light is reflected by the polarizer layer 82 of the polarizing plate 8, passes through the polarizer layer 72 of the polarizing plate 7, and proceeds in the + Y direction. On the other hand, in the optical path I2 incident on the side surface 41 of the triangular prism 4, the P-polarized component light passes through the polarizer layer 82 of the polarizing plate 8, is reflected by the polarizer layer 52 of the polarizing plate 5, and proceeds in the −Y direction.

  As shown in FIG. 9, the light incident from the side surface 21 of the triangular prism 2 is branched in the + Y direction and the −Y direction according to the polarization direction. In the optical path I3 incident on the side surface 21 of the triangular prism 2, the light of the S polarization component is reflected by the polarizer layer 62 of the polarizing plate 6 and travels in the −Y direction. On the other hand, in the optical path I3 incident on the side surface 21 of the triangular prism 2, the P-polarized component light is transmitted through the polarizer layer 62 of the polarizing plate 6, reflected by the polarizer layer 72 of the polarizing plate 7, and proceeds in the + Y direction. In the optical path I4 incident on the side surface 21 of the triangular prism 2, the P-polarized component light is reflected by the polarizer layer 52 of the polarizing plate 5, passes through the polarizer layer 62 of the polarizing plate 6, and proceeds in the −Y direction. On the other hand, in the optical path I4 incident on the side surface 21 of the triangular prism 2, the S-polarized component light is transmitted through the polarizer layer 52 of the polarizing plate 5, reflected by the polarizer layer 82 of the polarizing plate 8, and travels in the -Y direction.

  Here, the polarizing plates 5, 6, 7, and 8 may be polarizing plates that transmit the specific polarization component and reflect the light of the polarization component orthogonal to the specific polarization component. In the third embodiment, a polarizing plate in which polarizer layers 52, 62, 72, and 82 are formed on flat substrates 51, 61, 71, and 81, respectively, is used. A wire grid structure or the like may be used as the polarizer. As a material of the flat substrates 51, 61, 71, 81 of the polarizing plates 5, 6, 7, 8, the transparent material that can transmit light in the use band (for example, visible light region and infrared region), for example, glass, sapphire Crystal, etc. can be used. In this embodiment, it is preferable to use glass, particularly inexpensive and durable quartz glass (refractive index 1.46) or Tempax glass (refractive index 1.51). Moreover, it is not limited to glass, and plastic may be used. Use of plastic on the film is more preferable because the gap between the prisms can be narrowed.

Next, the polarizer layer will be described.
The polarizer layers 52, 62, 72, and 82 of the polarizing plates 5, 6, 7, and 8 have, for example, a polarizer layer formed in a wire grid structure, and the surface thereof is an uneven surface. This wire grid structure is a structure in which metal wires (conductor lines) made of metal such as aluminum and extending in a specific direction are arranged at a specific pitch. In the polarizer layer shown in FIG. 9, when light in the polarization direction in the groove direction is incident, it is reflected, and when light in the polarization direction perpendicular to the groove is incident, it is transmitted. By setting the wire pitch of the wire grid structure to a sufficiently small pitch (for example, ½ or less) compared to the wavelength band of incident light (for example, the wavelength of visible light: 400 [nm] to 800 [nm]), The effect of. That is, almost all the light of the electric field vector component that oscillates parallel to the longitudinal direction of the metal wire is reflected, and almost all the light of the electric field vector component that oscillates in the direction orthogonal to the longitudinal direction of the metal wire is transmitted. It can be used as a polarizer layer that produces a single polarization. In general, in a polarizer layer having a wire grid structure, when the cross-sectional area of the metal wire increases, the extinction ratio increases, and the transmittance of a metal wire having a predetermined width or more with respect to the periodic width decreases. Moreover, when the cross-sectional shape orthogonal to the longitudinal direction of the metal wire is a tapered shape, the wavelength dispersion of transmittance and polarization degree is small in a wide band and high extinction ratio characteristics are exhibited.

  And it has the following effects by forming a polarizer layer by a wire grid structure. That is, the wire grid structure can be formed using a widely known semiconductor manufacturing process. Specifically, after depositing an aluminum thin film on a flat substrate, patterning is performed, and the sub-wavelength uneven structure of the wire grid may be formed by a technique such as metal etching. In addition, since the wire grid structure is made of a metal material such as aluminum or titanium, there is an advantage that it is excellent in heat resistance and can be suitably used even in an environment where high temperatures are likely to occur. Since the wire grid structure is a submicron order structure, it is desirable to protect it when handling such as assembly is assumed.

Moreover, when closely bonding to another member (prism etc.), it is desirable to arrange | position in parallel and it is desirable that the filler is formed as a planarization layer. The filler is filled in the recesses between the metal wires of the polarizer layer. As the filler, an inorganic material having a refractive index lower than or equal to that of the planar substrate can be suitably used. The filler in Embodiment 3 is formed so as to cover the upper surface in the stacking direction of the metal wire portion of the polarizer layer. As the material for the filler, it is necessary to use a material that can flatten the uneven surface of the polarizer layer and does not interfere with the function of the polarizer layer. Therefore, it is preferable to use a material that does not have a polarization function. Further, it is preferable to use a low refractive index material whose refractive index is as close as possible to the refractive index of air (refractive index = 1). As a specific material of the filler, for example, a porous ceramic material formed by dispersing fine pores in ceramics is preferable. More specifically, porous silica (SiO ₂ ), porous magnesium fluoride (MgF), porous alumina (Al ₂ O ₃ ), and the like can be given.

Furthermore, the degree of these low refractive indexes is determined by the number and size (porosity) of pores in the ceramic. When the main component of the flat substrate is made of quartz or glass, porous silica (n = 1.2-1.26) can be preferably used. The method for forming the filler is not limited to this, but, for example, an SOG (Spin On Glass) method can be suitably used. Specifically, a solvent in which silanol (Si (OH) ₄ ) is dissolved in alcohol is spin-coated on a polarizer layer formed on a flat substrate, and then the solvent component is volatilized by heat treatment to remove the silanol itself. It can be formed by a dehydration polymerization reaction. The polarizer layer has a sub-wavelength sized wire grid structure, has low mechanical strength, and a metal wire is damaged by a slight external force. Since it is desired that the polarizing plate is disposed in close contact with the triangular prism, there is a possibility that the polarizing plate and the triangular prism are in contact with each other in the manufacturing stage.

  In the present embodiment, since the upper surface of the polarizer layer in the stacking direction is covered with the filler, it is possible to suppress a situation in which the wire grid structure is damaged when contacting the triangular prism. Further, by filling the recesses between the metal wires in the wire grid structure of the polarizer layer as in the present embodiment, it is possible to prevent foreign matter from entering the recesses.

  Next, an imaging apparatus according to an embodiment of an optical apparatus to which the above-described cross prism is applied will be described. FIG. 10 is a schematic diagram illustrating a partial configuration of the imaging apparatus according to the first embodiment. The present invention can be applied to an optical device that synthesizes light paths of P-polarized component light incident from the side surface 301 and S-polarized component light incident from the side surface 302 in the direction of the side surface 303. For example, the present invention can be applied to an imaging device described later. Further, the light incident on the side surface 303 can be applied to an optical device that emits a P-polarized component in the direction of the side surface 301 and emits an S-polarized component in the direction of the side surface 302. For example, it is suitable for an optical device in which an illumination light source is disposed on the side surface 303 side to split the polarized light.

  Next, a configuration of an imaging apparatus that is an example of the optical apparatus according to the embodiment will be described. FIG. 11 is a schematic diagram illustrating the overall configuration of the imaging apparatus according to the first embodiment. As shown in FIG. 11, in the imaging apparatus 400, an imaging element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the imaging element 402. A subject is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. The imaging apparatus 400 includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels as the optical filter 403. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404. The polarization-selective cross prism 300 polarization-reflects the S-polarized component light incident on the side surface 301 from the −Y direction and the P-polarized component light incident on the side surface 302 from the + Y direction in the direction of the side surface 303. As a result, an S-polarized image in the −Y direction and a P-polarized image in the + Y direction can be extracted. In contrast to a conventional imaging apparatus including a single imaging element and a single lens, which detects a subject in the + Z direction, in this embodiment, it is possible to shoot a subject in two directions in the ± Y direction. In addition, images in two directions can be detected independently and simultaneously.

  Here, the present imaging apparatus can be used, for example, as an apparatus mounted on a car to check both the left and right sides of the car as shown in FIG. The imaging device 500 is provided at the center of the front end of the automobile 501 and below the bumper, and a monitor device (see FIG. 12) installed on an instrument panel or the like near the driver's seat of the automobile 501. Yes. Information on both the left and right sides photographed by the imaging device is converted into a video signal, and as shown in FIG. 13, the information on both the left and right sides converted into the video signal is displayed on the monitor device 502 as left and right side images. Information on both the left and right sides of the automobile 501 can be acquired, and early information can be confirmed at an intersection where the left and right fields of view are difficult to see, and driving safety can be ensured.

  FIG. 14 is a schematic diagram illustrating a partial configuration of the imaging apparatus according to the second embodiment. As illustrated in FIG. 15, which is a schematic diagram of the overall configuration of the image pickup apparatus according to the second embodiment, the image pickup apparatus includes an image pickup element 402 mounted on a substrate 401, and an optical filter 403 disposed in close contact with the image pickup element 402. . Subject information is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. The optical filter 403 includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404. The polarization selective cross prism 300 polarization-reflects S-polarized component light incident on the side surface 301 from the −Y direction and P-polarized component light incident on the side surface 302 from the + Y direction in the direction of the side surface 303. As a result, an S-polarized image in the −Y direction and a P-polarized image in the + Y direction can be extracted.

  The imaging apparatus of FIG. 14 is the same as the imaging apparatus of FIG. 10 in terms of the optical system configuration of the imaging apparatus, but the imaging lens 404 to the substrate 401 are a fixed optical system, whereas a polarization selective cross prism is used. 300 is configured to be rotatable about the Z-axis. A well-known motor or the like may be used as the rotation method. By adopting such a configuration, it is possible to realize an imaging apparatus capable of acquiring 360-degree image information about the Z-axis center. A conventional imaging device including a single imaging element and a single lens detects a subject in one direction, but in the present embodiment, an image of 360 degrees about the Z-axis center can be taken. In addition, it is possible to detect images in two directions independently and simultaneously in ± Y. For this reason, since information per frame is twice that of the conventional imaging apparatus, high-speed imaging is possible.

  The imaging apparatus can be used, for example, as a vehicle equipped with an automobile and used to check the vehicle surrounding information as shown in FIG. The image pickup apparatus 601 equipped on the automobile ceiling and the monitor apparatus 602 installed on an instrument panel (instrument panel) or the like close to the driver's seat of the automobile are configured. Information around the vehicle imaged by the imaging device is converted into a video signal and displayed on the monitor device 602 as shown in FIG. If there is an obstacle, the information can be warned. Furthermore, it is possible to acquire 360-degree information around the automobile, and it is possible to detect parking assistance and traveling vehicle information around the host vehicle and use a warning to the driver, thereby ensuring driving safety. it can.

  17 and 18 are diagrams illustrating a configuration of the imaging apparatus according to the third embodiment. As shown in FIG. 18, in the imaging apparatus of the present embodiment, an imaging element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the imaging element 402. Subject information is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. Further, a lens 304 is provided in the vicinity of the side surface 301 and the side surface 302 of the polarization selective cross prism 300.

  The imaging apparatus according to the third embodiment includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels as the optical filter 403. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404. The polarization-selective cross prism 300 polarization-reflects the S-polarized component light incident on the side surface 301 from the −Y direction and the P-polarized component light incident on the side surface 513 from the + Y direction in the side surface 511 direction. As a result, it is possible to extract an S-polarized image in the −Y direction and a P-polarized image in the + Y direction.

  The image pickup apparatus according to the third exemplary embodiment includes a lens 304 for widening the field angle range. In order to widen the angle, a concave lens may be used. By adopting an optical system configuration such that the field angle range is, for example, 180 degrees or more, it is possible to take an image of 360 degrees about the Z axis as in the second embodiment. Compared to the second embodiment, no means for rotating is required, so that mechanical deterioration due to vibration or the like can be avoided, and an imaging device having a long life can be realized. In addition, since a 360-degree image can always be taken, it is possible to form a 360-degree image at a higher speed.

  By adopting such a configuration, it is possible to realize an imaging apparatus capable of acquiring 360-degree image information about the Z-axis center. A conventional imaging device including a single imaging element and a single lens detects a subject in one direction, but in the present embodiment, an image of 360 degrees about the Z-axis center can be taken.

  The imaging apparatus according to the third embodiment can be used, for example, as a vehicle equipped with an automobile, and as shown in FIG. The image pickup apparatus 601 equipped on the automobile ceiling and the monitor apparatus 602 installed on an instrument panel (instrument panel) or the like close to the driver's seat of the automobile are configured. Information around the vehicle imaged by the imaging device is converted into a video signal and displayed on the monitor device 602 as shown in FIG. If there is an obstacle, the information can be warned. Furthermore, it is possible to acquire 360-degree information around the automobile, and it is possible to detect parking assistance and traveling vehicle information around the host vehicle and use a warning to the driver, thereby ensuring driving safety. it can. Compared to the case of using the image pickup apparatus according to the second embodiment, there is an advantage that a processing load such as conversion from rotated image information to a peripheral image can be reduced.

  19 and 20 are diagrams illustrating a configuration of an imaging apparatus according to a fourth embodiment. As shown in FIG. 20, in the imaging apparatus of the present embodiment, an imaging element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the imaging element 402. Subject information is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. Further, a lens 304 is provided in the vicinity of the side surface 301 and the side surface 302 of the polarization selective cross prism 300.

  The imaging apparatus according to the fourth embodiment includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels as the optical filter 403. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404. The polarization-selective cross prism 300 polarization-reflects the S-polarized component light incident on the side surface 301 from the −Y direction and the P-polarized component light incident on the side surface 302 from the + Y direction in the direction of the side surface 303. As a result, it is possible to extract an S-polarized image in the −Y direction and a P-polarized image in the + Y direction.

  In the imaging apparatus according to the fourth embodiment, a known telecentric lens is provided as the imaging lens 404. A telecentric lens is a lens having a deep depth of field and a constant magnification within that range. Compared to the image pickup apparatus of the third embodiment, the distance between the image pickup lens 404 and the cross prism 300 can be increased. This makes it possible to simultaneously capture an image in the + Y direction and an image in the −Y direction at a distance from the imaging lens. A conventional imaging device including a single imaging element and a single telecentric lens detects a subject in the + Z direction, whereas in this embodiment, a 360-degree image centered on the Z axis can be taken.

  Example 5 of the imaging apparatus of the present embodiment is used, for example, as an industrial application, for inspection of scratches on the inner surface of a cylindrical object, inspection of a coating state after painting, etc., as shown in FIG. Is possible. The inspection device 700 includes an imaging device in which a cross prism 701 and an imaging lens portion (portion from the imaging lens to the substrate) are supported by a cylindrical casing 702, and a monitor device (not shown). As shown in FIG. 22, foreign objects 704 and 705 may be attached to a cylindrical inspection object 703. In this case, if the inspection apparatus 700 having the present imaging device is used, the attachment and position of the foreign matter are detected from the foreign matter image portions 704-1 and 705-1 displayed on the 360 degree image as shown in FIG. Can be identified. In this manner, information on the inside of the cylindrical object to be inspected can be acquired, and information such as defects that are difficult to see from the outside can be confirmed.

  24 and 25 are diagrams illustrating the configuration of the sixth embodiment of the imaging apparatus. As shown in FIG. 25, in the imaging apparatus of the present embodiment, an imaging element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the imaging element 402. Subject information is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. Further, triangular prisms 305 and 306 are arranged in the vicinity of the side surfaces 301 and 302 of the polarization selective cross prism 300.

  The imaging apparatus according to the sixth embodiment includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels as the optical filter 403. Further, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404, and triangular prisms 305 and 306 are disposed adjacent to the cross prism 300, respectively. The triangular prisms 305 and 306 have total reflection surfaces that reflect and reflect light from the + Z direction in the Y-axis direction. The polarization-selective cross prism 300 polarizes and reflects the S-polarized component light incident on the side surface from the -Y direction and the P-polarized component light incident on the side surface from the + Y direction in the side surface direction. As a result, it is possible to extract an S-polarized image in the −Y direction and a P-polarized image in the + Y direction.

  Unlike the imaging apparatus of the first embodiment, it is possible to simultaneously capture a P-polarized image and an S-polarized image in the + Z direction. Further, as apparent from FIG. 25, since there is a certain distance between the light ray effective ranges of the left and right triangular prisms 305 and 306, it is possible to form a parallax image from the P-polarized image and the S-polarized image. As described above, the image pickup apparatus according to the present exemplary embodiment is configured as a stereo image pickup apparatus capable of shooting the distance information to the subject. Compared to a conventional stereo image pickup apparatus in which two single lenses and a single lens are arranged in parallel, only one image pickup lens and one image pickup element are required, so that the cost can be reduced. In addition, in the conventional stereo imaging device, a distance measurement error due to a change in the baseline length due to thermal expansion of the housing supporting the lenses occurs. However, since this embodiment has only one imaging lens, such an error is suppressed. It is possible.

  The image pickup apparatus according to the sixth embodiment can be used, for example, for confirming the front of a vehicle as shown in FIG. The vehicle front confirmation device includes an image pickup device 801 installed near a rearview mirror inside an automobile windshield, and a signal processing device 802 for warning a driver and controlling the vehicle based on information from the image pickup device 801. It is comprised including. As a warning method to the driver, the obstacle information is warned by voice or the like using a speaker. As vehicle control, if there is an obstacle, the vehicle is decelerated. If the imaging device of this embodiment is used, it is possible to acquire not only image information in front of the vehicle but also distance information to the preceding vehicle or pedestrian in front of the vehicle, and if there is an obstacle, an early warning is given to the driver. Thus, driving safety can be ensured.

  27 and 28 are diagrams illustrating the configuration of an imaging apparatus according to a seventh embodiment. As shown in FIG. 28, in the imaging apparatus of the present embodiment, an imaging element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the imaging element 402. Subject information is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. Further, triangular prisms 305 and 306 are provided in the vicinity of the side surfaces 301 and 302 of the polarization-selective cross prism 300, and optical filters 307 and 308 having different characteristics on the left and right are provided in front of the left and right triangular prisms 305 and 306, respectively. Is arranged.

  In the image pickup apparatus according to the seventh embodiment, the optical filter 403 includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404, and two triangular prisms 305 and 306 are disposed adjacent to the cross prism 300. The triangular prisms 305 and 306 have total reflection surfaces that reflect and reflect light from the + Z direction in the Y-axis direction. The polarization-selective cross prism 300 polarization-reflects the S-polarized component light incident on the side surface 301 from the −Y direction and the P-polarized component light incident on the side surface 302 from the + Y direction in the direction of the side surface 303. As a result, it is possible to extract an S-polarized image in the −Y direction and a P-polarized image in the + Y direction.

  Unlike the imaging apparatus of the first embodiment, it is possible to simultaneously capture a P-polarized image and an S-polarized image in the + Z direction. The P-polarized image and the S-polarized image can be taken through optical filters 307 and 308, respectively. Two types of images in different wavelength bands in the + Z direction can be taken simultaneously, such as an IR cut filter as the optical filter 307 and an IR bandpass filter that transmits only IR light as the optical filter 308. The IR cut filter has a transmission wavelength range of 450 [nm] to 700 [nm], and the filter that transmits only IR light has a transmission wavelength range of 850 [nm] to 1000 [nm]. Whereas a conventional imaging device including a single imaging element and a single lens detects one type of subject in the + Z direction, the imaging device of the seventh embodiment utilizes the difference between the left and right optical filters, It is possible to extract shooting information of two types of subjects in the + Z direction. Also, two images can be detected independently and simultaneously.

  The image pickup apparatus according to the seventh embodiment can be used, for example, as a device for confirming the front of a vehicle as shown in FIG. The vehicle front confirmation device includes an imaging device 801 and a signal processing device 802 that are installed in the vicinity of a rearview mirror inside an automobile windshield. Information on preceding vehicles and pedestrians in front of the vehicle can be acquired, and if there is an obstacle, driving safety such as an early warning to the driver can be ensured. According to the imaging apparatus of the present embodiment, since an IR-cut image can be taken, daytime obstacle detection can be performed in a state where unnecessary external light information is excluded. Further, by providing the headlight with a near-infrared LED lamp or the like, it is possible to photograph an obstacle even at night.

  In place of the optical filters 306 and 307 of the seventh embodiment, different lenses may be arranged on the left and right so as to form different field distances on the left and right. For example, a short distance image and a long distance image can be taken simultaneously.

  29 and 30 are diagrams illustrating the configuration of an imaging apparatus according to an eighth embodiment. As shown in FIG. 30, in the image pickup apparatus of this embodiment, an image pickup element 402 is mounted on a substrate 401, and an optical filter 403 is disposed in close contact with the image pickup element 402. A subject is photographed through the imaging lens 404. A polarization selection type cross prism 300 is disposed in front of the imaging lens 404. Further, a lens 304 is disposed in the vicinity of the side surface 302 of the polarization selective cross prism 300. A triangular prism 305 is disposed in the vicinity of the side surface 301 of the polarization selective cross prism 300.

  The imaging apparatus according to the eighth embodiment includes a region-dividing polarization filter that can extract P-polarization information and S-polarization information in units of pixels as the optical filter 403. In addition, a polarization-selective cross prism 300 is disposed in front of the imaging lens 404. The polarization-selective cross prism 300 polarizes and reflects the S-polarized component light and the P-polarized component light incident on the side surface from the Z direction in the side surface direction. Thereby, it is possible to extract the S-polarized image and the P-polarized image in the Z direction.

  Unlike the image pickup apparatus according to the first embodiment, an image in the + Z direction by the triangular prism 305 and an image on the + Y direction side in which the angle of view is changed by the lens 304 can be taken. In contrast to the conventional imaging apparatus including a single imaging element and a single lens, which detects a subject in the + Z direction, the present invention can shoot subjects in the + Z direction and the −Y direction. In addition, images in two directions can be detected independently and simultaneously.

  For example, as shown in FIG. 31, the image pickup apparatus according to the eighth embodiment can be used to check the rear side of the automobile and the lower side of the vehicle side surface. The vehicle rear and side confirmation device includes an imaging device 901 installed near a side mirror of an automobile, and a monitor device 902 installed on an instrument panel (instrument panel) or the like near the driver's seat of the automobile. . It is possible to acquire image information such as vehicles and side grooves on the rear and side of the vehicle, and it is possible to ensure driving safety by photographing a portion that is difficult for the driver to see.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect 1)
The polarizing device includes a first polarizing plate and a second polarizing plate, and the first polarizing plate has one polarization direction among polarization directions in which a polarizer layer is formed and the polarization directions are orthogonal to each other. The second polarizing plate has one polarization direction among the polarization directions in which the polarizer layer is formed and the polarization directions are orthogonal to each other, reflecting the component image light and transmitting the other polarization component image light. The first polarizing plate and the second polarizing plate so that the image light of the polarization component is transmitted and the image light of the other polarization component is reflected, and the angle formed by the first polarizing plate and the second polarizing plate is a predetermined angle. The polarization component of the image light transmitted through the first polarizing plate and the polarization component of the image light transmitted through the second polarizing plate and reflected by the first polarizing plate have polarization directions orthogonal to each other, and The polarization component of the image light passing through the two polarizing plates and the first polarizing plate and reflected by the second polarizing plate Having mutually perpendicular polarization directions and the polarization component of the image light. According to this, as described in the first embodiment, the image light incident from the back surface of the first polarizing plate and the image light incident from the back surface of the second polarizing plate are reflected and transmitted by the polarizing device. Since the steps are performed in substantially the same manner, the optical path length is the same. For this reason, the image light of two polarization components having different polarization directions emitted from the polarization device passes through the first region and the second region of the optical polarization filter, and the image light of one polarization component and the other polarization It is separated into component image light. The magnitudes of two images generated based on the image signal by photoelectrically converting the separated two polarized light components by the image sensor are displayed on the monitor in the same manner. Therefore, it is possible to capture images in two directions having the same size without adjusting the optical conditions of the optical system. In addition, since the optical path lengths of the image light captured from the back surface of the first polarizing plate and the image light captured from the back surface of the second polarizing plate are substantially the same, an increase in size of the apparatus can be suppressed.
(Aspect 2)
In (Aspect 1), the polarizing device includes two first polarizing plates, and two second polarizing plates arranged so as to make a predetermined angle in contact with the edge of each first polarizing plate, Provided so that the polarization plane of one first polarizing plate faces the polarization plane of one second polarizing plate, and the polarization plane of the other first polarizing plate faces the polarization plane of the other second polarizing plate. The first polarizing plate and the second polarizing plate are provided so that the angle formed by the first polarizing plate and the second polarizing plate is a predetermined angle, and the second polarizing plate is reflected by the first polarizing plate. The polarization component of the image light that passes through the first polarizing plate and the polarization component of the image light that passes through the first polarizing plate and reflected by the second polarizing plate have polarization directions orthogonal to each other, pass through the second polarizing plate, and pass through the first polarizing plate. The polarization component of the image light reflected by the polarizing plate and the polarization component of the image light reflected by the second polarizing plate and transmitted through the first polarizing plate are orthogonal to each other. That has a polarization direction. According to this, as described in the first embodiment, the light incident from the side opposite to the back surface of one of the first polarizing plates and the front surface of the other second polarizing plate and the one of the second polarized light Light incident from the back surface of the plate and the side facing the front surface of the other first polarizing plate is reflected and transmitted by the polarizing device in substantially the same manner and has the same optical path length. For this reason, image light taken from the back surface of one first polarizing plate and the front surface of the other second polarizing plate, and the back surface of one second polarizing plate and the other first polarized light Image light taken from the side opposite to the front surface of the plate enters the polarizing device.
(Aspect 3)
In (Aspect 2) or (Aspect 3), a triangular prism is provided in at least one of the polarizing plates facing each other on the surface on which the polarizer layer is formed to constitute a cross prism. According to this, as described in the first embodiment, the plate aberration of the polarizing plate can be reduced.
(Aspect 4)
In (Aspect 3), the cross prism is rotated about the optical axis of the imaging lens to capture an image. According to this, as described in the first embodiment, it is possible to take an image of 360 degrees about the Z axis. In addition, since the information per frame is twice that of the conventional imaging apparatus, high-speed imaging is possible.
(Aspect 5)
In (Aspect 1) or (Aspect 2), a lens that widens the angle of view is provided in front of the first polarizing plate and the second polarizing plate, respectively. According to this, as described in the first embodiment, since the rotating means is not necessary, mechanical deterioration due to vibration or the like can be avoided, and an imaging device having a long life can be realized. In addition, since a 360-degree image can always be taken, it is possible to form a 360-degree image at a higher speed.
(Aspect 6)
In (Aspect 1) or (Aspect 2), a triangular prism is provided in front of the first polarizing plate and the second polarizing plate, respectively. According to this, as described in the first embodiment, it is possible to extract the S-polarized image in the −Y direction and the P-polarized image in the + Y direction.
(Aspect 7)
In (Aspect 6), optical filters having different transmission wavelength bands are provided in front of each triangular prism. According to this, as described in the first embodiment, two types of images in different wavelength bands in the + Z direction can be taken simultaneously, such as an IR bandpass filter that transmits only IR light as an optical filter.
(Aspect 8)
In (Aspect 1) or (Aspect 2), a triangular prism is provided in one stage of the first polarizing plate or the second polarizing plate, and the angle of view is widened in the other stage of the first polarizing plate or the second polarizing plate. Provide a lens. According to this, as described in the first embodiment, it is possible to extract the S-polarized image in the −Y direction and the P-polarized image in the + Y direction.
(Aspect 9)
In (Aspect 1) or (Aspect 2), the imaging lens is a telecentric lens. According to this, as described in the first embodiment, the telecentric lens is a lens having a deep depth of field and a constant magnification in the range. The distance between the imaging lens 404 and the cross prism 300 can be increased. This makes it possible to simultaneously capture an image in the + Y direction and an image in the −Y direction at a distance from the imaging lens. A conventional imaging device including a single imaging element and a single telecentric lens detects a subject in the + Z direction, whereas in this embodiment, a 360-degree image centered on the Z axis can be taken.
(Aspect 10)
The imaging device according to any one of (Aspect 1) to (Aspect 9) is mounted on a vehicle, and images in the left-right direction of the vehicle are taken. According to this, as described in the first embodiment, it can be used to check both the left and right sides of the automobile. Information on both the left and right sides photographed by the imaging device is converted into a video signal, and the information on both the left and right sides converted into the video signal is displayed on the monitor device as left and right side images. Information on both the left and right sides of the vehicle can be acquired, and early information can be confirmed at intersections where the left and right fields of view are difficult to see, thereby ensuring driving safety.
(Aspect 11)
The imaging device according to (Aspect 4) is mounted on a vehicle, and an image of 360 degrees around the vehicle is captured. According to this, as described in the first embodiment, the vehicle surrounding information can be used for confirming photographing. If there is an obstacle, the information can be warned. Furthermore, it is possible to acquire 360-degree information around the automobile, and it is possible to detect parking assistance and traveling vehicle information around the host vehicle and use a warning to the driver, thereby ensuring driving safety. it can.
(Aspect 12)
The cylindrical interior is imaged using the imaging device according to (Aspect 4). According to this, as described in the first embodiment, it can be used for inspection of defects on the inner surface of a cylindrical object, inspection of a coating state after painting, and the like. In some cases, foreign matter is adhered to the cylindrical object to be inspected. In this case, if the inspection apparatus having the present imaging device is used, the attachment and position of the foreign matter can be specified from the image portion of the foreign matter displayed on the 360-degree image by the monitor device. In this manner, information on the inside of the cylindrical object to be inspected can be acquired, and information such as defects that are difficult to see from the outside can be confirmed.
(Aspect 13)
The imaging device according to any one of (Aspect 1) to (Aspect 9) is mounted on a vehicle, and the front of the vehicle is imaged by the imaging device to obtain a stereo image. According to this, as described in the first embodiment, the parallax image can be formed from the P-polarized image and the S-polarized image because there is a certain distance between the light beam effective ranges of the left and right prisms. .
(Aspect 14)
In (Aspect 7), one of the optical filters is an IR cut filter, and the other of the optical filters is an IR bandpass filter. According to this, as described in the first embodiment, it is possible to extract shooting information of two types of subjects in the + Z direction using the difference between the left and right optical filters. Also, two images can be detected independently and simultaneously.
(Aspect 15)
The imaging device according to (Aspect 6) is mounted on a vehicle, and images are captured in two directions, the rear side and the lower side of the vehicle. According to this, as described in the first embodiment, it can be used to confirm the vehicle rear side and the vehicle side lower side of the automobile. It is possible to acquire image information such as vehicles and side grooves on the rear and side of the vehicle, and it is possible to ensure driving safety by photographing a portion that is difficult for the driver to see.

DESCRIPTION OF SYMBOLS 1 Triangular prism 2 Triangular prism 3 Triangular prism 4 Triangular prism 10 Cross prism 100 Imaging device 101 Substrate 102 Imaging element 103 Optical polarizing filter 103-1 Filter substrate 103-2 Polarizing filter layer 103-3 Filling layer 104 Imaging lens 105 Cross prism 106 Signal processing unit 120 Image analysis unit 200 Polarizing device 201 First polarizing plate 202 First polarizing plate 203 Second polarizing plate 204 Second polarizing plate 300 Cross prism 304 Lens 400 Imaging device 401 Substrate 402 Imaging element 403 Optical polarizing filter 404 Imaging lens 500 Imaging Device 501 Automobile 502 Monitor Device 601 Imaging Device 602 Monitor Device 700 Inspection Device 701 Cross Prism 702 Case 703 Object 704 Foreign Object 704-1 Foreign Object Image Part 705 Foreign Object 7 05-1 Image area of a foreign object

JP 2010-254085 A

Claims (15)

A polarizing device, an optical polarizing filter, and an imaging device, wherein the optical polarizing filter is provided between the polarizing device and the imaging device, and has one of the polarization directions orthogonal to each other. A plurality of first regions that transmit image light of one polarization component and a plurality of second regions that transmit image light of the other polarization component having the other polarization direction out of the polarization directions whose polarization directions are orthogonal to each other, One polarization component image light in the first image light captured from one of the two directions by the polarization device and one polarization component image light in the second image light captured from the other direction are 1 In the optical polarizing filter, the image light incident from the polarizing device is passed through each first region to be polarized in one of the first image lights. The image light is separated into component image light and separated into image light of the other polarization component in the second image light by passing through each second region, and the image light of the two separated polarization components is photoelectrically converted by the imaging device. In an imaging device that outputs an image signal,
The polarizing device includes a first polarizing plate and a second polarizing plate,
The first polarizing plate is formed with a polarizer layer, and reflects the image light of one polarization component having one polarization direction out of the polarization directions orthogonal to each other and transmits the image light of the other polarization component. And
The second polarizing plate includes a polarizer layer and transmits image light of one polarization component having one polarization direction out of polarization directions whose polarization directions are orthogonal to each other, and reflects image light of the other polarization component. And
The first polarizing plate and the second polarizing plate are provided so that an angle formed between the first polarizing plate and the second polarizing plate is a predetermined angle;
The polarization component of the image light transmitted through the first polarizing plate and the polarization component of the image light transmitted through the second polarizing plate and reflected by the first polarizing plate have polarization directions orthogonal to each other,
The polarization component of the image light transmitted through the second polarizing plate and the polarization component of the image light transmitted through the first polarizing plate and reflected by the second polarizing plate have polarization directions orthogonal to each other. Imaging device. The imaging device according to claim 1,
The polarizing device includes two first polarizing plates and two second polarizing plates that are arranged so as to make a predetermined angle in contact with the edge portions of the first polarizing plates. The polarizing plane of the plate and the polarizing plane of one second polarizing plate are opposed to each other, and the polarizing plane of the other first polarizing plate and the polarizing plane of the other second polarizing plate are opposed to each other,
The first polarizing plate and the second polarizing plate are provided so that an angle formed between the first polarizing plate and the second polarizing plate is a predetermined angle;
The polarization component of image light reflected by the first polarizing plate and transmitted through the second polarizing plate is orthogonal to the polarization component of image light transmitted through the first polarizing plate and reflected by the second polarizing plate. Having a polarization direction;
The polarization component of the image light transmitted through the second polarizing plate and reflected by the first polarizing plate and the polarization component of the image light reflected by the second polarizing plate and transmitted through the first polarizing plate are mutually An imaging apparatus having orthogonal polarization directions. The imaging device according to claim 1 or 2,
An imaging apparatus comprising a cross prism by providing a triangular prism in at least one of polarizing plates facing each other on a surface on which the polarizer layer is formed. The imaging device according to claim 3.
An image pickup apparatus for picking up an image by rotating the cross prism about an optical axis of an image pickup lens. The imaging device according to claim 1 or 2,
An imaging apparatus comprising a lens that widens an angle of view in front of the first polarizing plate and the second polarizing plate. The imaging device according to claim 1 or 2,
An imaging apparatus comprising a triangular prism in front of the first polarizing plate and the second polarizing plate, respectively. The imaging device according to claim 6.
An imaging apparatus comprising an optical filter having transmission wavelength bands different from each other in front of each triangular prism. The imaging device according to claim 1 or 2,
A triangular prism is provided in front of either the first polarizing plate or the second polarizing plate, and a lens that widens the angle of view is provided in front of either the first polarizing plate or the second polarizing plate. An imaging apparatus characterized by that. The imaging device according to claim 1 or 2,
The imaging device is a telecentric lens.   An image pickup apparatus comprising: the image pickup apparatus according to claim 1 mounted on a vehicle;   An imaging apparatus comprising: the imaging apparatus according to claim 4 mounted on a vehicle, and imaging an image of 360 degrees around the vehicle.   An imaging device characterized in that the inside of a cylindrical shape is imaged using the imaging device according to claim 4.   An imaging apparatus comprising: the imaging apparatus according to claim 1 mounted on a vehicle; and capturing a front image of the vehicle with the imaging apparatus to obtain a stereo image. The imaging device according to claim 7.
One of the optical filters is an IR cut filter, and the other of the optical filters is an IR bandpass filter.   An imaging apparatus comprising: the imaging apparatus according to claim 6 mounted on a vehicle;

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