JP2014215405A - Imaging element and microscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a reduction in resolution of a stereoscopic photographed image in an imaging element of stereoscopic photographed images used for an optical device with a relatively large F number.SOLUTION: An imaging element includes a pair of light receiving elements arranged in each of lenses arranged in matrix and receive light from a subject, where one of the pair of light receiving elements outputs pixel signals constituting one of a pair of photographed images having parallax to display a stereoscopic photographed image of the subject, and the other of the pair of light receiving elements in the row direction outputs pixel signals constituting the other of the pair of photographed images; and a dead zone that is provided between the pair of light receiving elements to separate the pair of light receiving elements in the row direction. When the length in the row direction of the pair of light receiving elements is p, and the width in the row direction of the dead zone is d, 0.04≤p/f≤0.08 is satisfied, and thereby a loss in the light receiving amount due to the dead zone is reduced.

Description

  The present invention relates to an image sensor having a light receiving element pair that is arranged for each lens arranged in a matrix and receives light from a subject, and a microscope apparatus having the image sensor.

  There is known a microscope apparatus that displays a magnified image of an observation object as a three-dimensional image. Such a microscope apparatus captures an enlarged image of an object to be observed by an objective lens with an image sensor, and displays a stereoscopic image on a display screen. The imaging device used here has a configuration for capturing a pair of captured images having parallax for displaying a stereoscopic captured image. Specifically, the imaging device includes a pair of light receiving elements that form a pair on the left and right for each microlens arranged in a matrix. Light from the object to be observed that has passed through the microlens (hereinafter referred to as subject light) forms an image on the light receiving surface of the light receiving element pair. The light receiving element pair corresponds to a pixel pair (hereinafter referred to as a picture element) constituting a captured image pair, and the left eye receiving element for the left eye and the right eye receiving element for the right eye. Pixel signals constituting the image are output. An example of such an image sensor is described in Patent Document 1.

Japanese Patent No. 4027113

  The image sensor has a dead zone that separates the light receiving elements with a certain width between the light receiving element pairs corresponding to the respective picture elements in order to obtain a good stereoscopic effect of the stereoscopic image. The dead zone is an area or a structure that does not transmit subject light and does not itself output a pixel signal by photoelectric conversion. The dead zone prevents subject light to be received by the left eye light receiving element from entering the right eye light receiving element and subject light to be received by the right eye light receiving element from entering the left eye light receiving element. As a result, it is avoided that the left and right subject lights are mixed and the stereoscopic effect of the stereoscopic image is lowered.

  However, due to providing a dead band with a certain width, the following problems arise. That is, when a part of the subject light to be received by the original light receiving element reaches the dead zone, the subject light of that part does not contribute to the generation of the pixel signal. If the amount of subject light that is lost in this way is large, the resolution of the captured image pair, that is, the stereoscopic image may be lowered. In particular, a microscope or the like requires a relatively large F-number on the image side in order to obtain a desired magnification, and accordingly, subject light passes through the microlens of the image sensor with a relatively small inclination. As a result, the ratio of the subject light that reaches the dead zone between the light receiving element pair in the subject light that has passed through the microlens increases when viewed for each pixel. Then, the above problem becomes more serious.

  Therefore, an object of the present invention made in view of the above problems is to reduce the resolution of a stereoscopic image in an imaging element for a stereoscopic image used in a relatively large F-number optical device such as a microscope. An object of the present invention is to provide an imaging device that can be prevented, and a microscope apparatus including the same.

In order to solve the above problems, an imaging device according to one aspect of the present invention is a light receiving element pair that is arranged for each lens arranged in a matrix and receives light from a subject, and one of the light receiving element pairs. The light receiving element outputs a pixel signal constituting one of the captured image pairs having parallax for displaying the stereoscopic image of the subject, and the other light receiving element in the row direction of the light receiving element pair, A light receiving element pair that outputs a pixel signal that constitutes the other of the captured image pairs; and a dead zone provided between the light receiving element pair so as to separate the light receiving element pair in a row direction, When the length in the row direction of the pair is p and the width in the row direction of the dead zone is d,
0.04 ≦ p / f ≦ 0.08
It is characterized by being.

When the focal length of the lens is f and the shift amount of the light receiving element from the rear focal point of the lens in the optical axis direction of the light from the subject is Δz,
−f / 10 ≦ Δz ≦ f / 10
It is good to be. further,
1/20 · p ≤ d ≤ 1/7 · p
It is good to be.
The lens may have a curved surface to be pointed.

  Another aspect of the present invention is a microscope apparatus that includes the above-described image sensor and captures an enlarged image of an observation object using the image sensor.

  Even when a relatively large F number is used for the image sensor and the image pickup apparatus of the present invention, it is possible to prevent the resolution of the stereoscopic image from being lowered.

It is a figure which shows the structural example of the principal part of a microscope apparatus. It is a block diagram which shows the structure of an imaging device. It is a figure which shows the structure of an image pick-up element. It is a figure explaining the image side F number of an imaging device, and the light reception area | region of a light receiving element. It is a figure explaining the image side F number of an imaging device, and the light reception area | region of a light receiving element. It is a figure explaining a dead zone. It is a figure which shows a response | compatibility with the magnification etc. of an objective lens, and an image side F number. It is a figure which shows the structure of the image pick-up element of 3rd Example. It is a figure which shows the structure of the image pick-up element of 3rd Example. It is a figure which shows the light receiving element pair in an Example.

  Embodiments of the present invention will be described below.

  FIG. 1 shows a configuration example of a main part of a microscope apparatus according to this embodiment. This microscope apparatus 1 is an example of a transmission type microscope apparatus. In the microscope apparatus 1, the light source 10 generates light 120 that passes through the subject. The built-in filter 102 selectively transmits visible light out of the light 120. The field stop 104 passes light corresponding to a preset field among the light 120 that has passed through the built-in filter 102. The mirror 105 reflects the light 120 and enters the condenser lens 107 through the window lens 106. The condenser lens 107 collects the light 120 that has passed through the internal aperture stop 108 and irradiates the object 122 with the light 120. The objective lens 109 refracts the light 120 transmitted through the object to be observed 122, that is, the subject light 121 and passes it through the imaging lens 110. The spectroscope 111 splits the subject light 121 that has passed through the imaging lens 110 and guides a part thereof to the eyepiece lens 112, the other part, and the imaging device 10. The eyepiece 112 refracts the subject light 121 and forms an enlarged image of the object 122 on the naked eye 114. Thus, the observer observes an enlarged image of the object to be observed with the naked eye 114. On the other hand, the imaging device 10 captures, for example, displays an enlarged stereoscopic image of the observation object 122 imaged by the subject light 121.

  FIG. 2 is a block diagram illustrating a configuration of the imaging apparatus 10. The imaging device 10 captures a pair of captured images having parallax for displaying a stereoscopic captured image of a subject (observed object) based on the subject light 121. The imaging device 10 includes an imaging element 20, an image processing unit 22, a control unit 24, a storage unit 26, and a display unit 28. The image sensor 20, the image processing unit 22, the control unit 24, the storage unit 26, and the display unit 28 are connected to a bus 29 and configured to be able to transmit and receive various signals to and from each other.

  When the subject light 121 is incident through the objective lens 109, the imaging element 20 captures a pair of captured images for the left eye and the right eye having parallax based on the subject light 121, and configures each captured image. A pixel signal is output. Each captured image is composed of pixels arranged in a matrix, and the number of pixels constituting one frame of the captured image is, for example, 640 × 480 pixels to 4000 × 3000 pixels (however, the number of pixels in one frame and the aspect ratio). The ratio need not be limited to this numerical range). The imaging element 20 is a complementary metal oxide semiconductor (CMOS) or a charge coupled device (CCD) having a light receiving element arranged corresponding to each pixel, and generates and outputs a pixel signal by the light receiving element. The pixel signal is generated and output for each frame, for example. The pixel signal is a signal indicating a gradation value of, for example, R (Red), G (Green), or B (Blue) color for each pixel. The pixel signal is a digital signal obtained by A / D converting an output signal from the light receiving element, for example.

  The image processing unit 22 performs predetermined image processing such as color, luminance correction, and distortion correction, and data compression / decompression on captured image data including pixel signals for one frame. For example, the image processing unit 22 performs image processing on captured image data for each frame. The image processing unit 22 is a processor such as a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit).

  The storage unit 26 is a frame memory that stores captured image data before and / or after image processing. The storage unit 26 is, for example, an SRAM (Static Random Access Memory) or a DRAM (Dynamic RAM). Alternatively, the storage unit 26 may include a device for reading and writing data to various storage media such as a hard disk and a portable flash memory.

  The display unit 28 displays a stereoscopic captured image based on the captured image data. The display unit 28 includes, for example, an LCD (Liquid Crystal Display) including a polarizing filter corresponding to the parallax between the left and right eyes and a control circuit thereof. The display unit 18 displays left and right captured image data having parallax, and displays a stereoscopic captured image that allows the user to perceive a stereoscopic effect.

  The control unit 24 sends control signals to the image sensor 20, the image processing unit 22, the storage unit 26, and the display unit 28 to control the operation of the imaging device 10 in an integrated manner. The control unit 24 is a microcomputer, for example.

  FIG. 3A is a configuration diagram in a plane (XY plane) perpendicular to the optical axis direction of the main part of the image sensor 20. The imaging device 20 includes a light receiving element pair 32P that is disposed for each micro 30 lens arranged in a matrix and receives light from a subject. The light receiving element pair 32P includes light receiving element pairs 32R and 32L adjacent in the row direction (X-axis direction). One light receiving element 32R outputs a pixel signal constituting one (for example, for the right eye) of a pair of captured images having parallax for displaying a stereoscopic image of the subject, and the other light receiving element 32L The pixel signal constituting the other (for example, for the left eye) of the captured image pair is output. Further, the imaging device 20 has a dead zone 38 provided between the light receiving element pair 32P so as to separate the light receiving element pair 32P in the X-axis direction. The dead zone 38 is an area or a structure that does not transmit subject light and does not itself output a pixel signal by photoelectric conversion. The dead zone 38 may be provided between the light receiving element pairs 38P in the X-axis direction.

  FIG. 3B is a cross-sectional view of the main part of the image sensor 20 along the optical axis direction (Z-axis direction). Subject light 121 is incident on the image sensor 20 via the objective lens 109. The subject light 121 passes through the objective lens 109 through the entrance pupil 33 and the exit pupil 34 having a diameter corresponding to the stop 31. The subject light 121 is collected by the microlens 30, and light having a wavelength corresponding to the color of the color filter 36 reaches the light receiving element 32. Thus, a subject image is formed on one of the light receiving elements 32L and 32R of the light receiving element pair 32P by any of R, G, and B light. The microlens 30 is, for example, a spherical lens having a pointed bent surface. Alternatively, the microlens 30 may be a cylindrical lens that bends in the X-axis direction.

  Looking at each light receiving element pair 32P, the left light beam 121L of the subject light 121 with respect to the optical axis 300 is incident on the left eye light receiving element 32L, and the right light beam 121R is incident on the right eye light receiving element 32R. Then, the light receiving element 32L generates and outputs a pixel signal of a pixel constituting the left-eye captured image. On the other hand, the light receiving element 32R generates and outputs a pixel signal of a pixel constituting a right-eye captured image. The light receiving element 32 is, for example, a photodiode included in a CMOS or CCD.

  The dead zone 38 separates the light receiving elements 32R and 32L in accordance with the width thereof in the X-axis direction. The dead zone 38 may be constituted by, for example, a wiring layer that transmits an input signal or an output signal of the light receiving element 32. In addition, for example, when the light receiving element 32 is configured by a back-illuminated CMOS and wiring is built in, the dead zone 38 may be configured by a light shielding film (wall) made of a light shielding member. Furthermore, by providing the dead zone 38 between the light receiving element pairs 38P in the X-axis direction, it is possible to reduce mixing of subject light between adjacent picture elements. Alternatively, a light shielding wall 37 that separates the microlens 30 in the row direction (X-axis direction) or the column direction (Y-axis direction) may be provided in the space between the microlens 30 and the light receiving element 32.

  4 and 5 are diagrams for explaining the F-number on the image side of the imaging apparatus 10 and the light receiving region of the light receiving element 32. FIG. 4A and 4B are simplified cross-sectional views of the main part of the image sensor 20. 4A and 4B correspond to the case where the F number on the image side is relatively small and the case where it is relatively large, respectively. 4A and 4B show subject light 121R and 121L that pass through the highest exit pupil of the objective lens 109 in each case. As shown in FIGS. 4A and 4B, when the F number on the image side is relatively small, the incident angle θ of the subject lights 121R and 121L on the macro lens 30 increases. On the other hand, when the F number is relatively large, the incident angle θ of the subject lights 121R and 121L becomes small.

  FIGS. 5A and 5B are plan views of the light receiving element pair 32P (light receiving elements 32R and 32L) in the cases of FIGS. 4A and 4B, respectively. 5A and 5B, the light receiving region 109a in the light receiving element pair 32P is shown in each case. The light receiving area 109 corresponds to the exit pupil image of the objective lens 109. As shown in FIGS. 5A and 5B, when the F number on the image side is relatively small, the light receiving region 109a corresponds to the increase in the incident angle θ of the subject light 121R and 121L in the macro lens 30. Will grow. On the other hand, when the F number is relatively large, the light receiving region 109a becomes relatively small corresponding to the decrease in the incident angle θ of the subject light 121R and 121L.

  FIGS. 5C and 5D show the light receiving region 109 in the case where the microlens 30 is formed of a cylindrical lens bent in the row direction. FIGS. 5C and 5D correspond to the cases of FIGS. 4A and 4B, respectively. In the case of a cylindrical lens, when the F number on the image side is large, a light receiving region 109 having a narrow width in the row direction is formed. On the other hand, when the F number on the image side is small, a light receiving region 109 having a wide width in the row direction is formed. In the case of a cylindrical lens, the size of the light receiving region 109 is larger than that in the case of a spherical lens.

  Here, in the light receiving region 109a, the portion of the subject light that overlaps the dead zone 38 does not contribute to the formation of the pixel signal and is damaged. This leads to problems in cases where the F number is relatively small and large, respectively.

  For example, when the F-number on the image side is relatively small, the light receiving area 109a itself becomes large, the overlap with the dead band 38 between the light receiving elements 32R and 32L, and the dead band 38 provided between the adjacent light receiving element pair 32P. The amount of received light is lost due to the overlap. In this case, the light passing through the vicinity of the extended portion of the light receiving region 109a, that is, the highest portion of the exit pupil of the objective lens 109 is damaged. This means that the pixel signal of the most parallax portion of the captured image pair cannot be obtained. Therefore, the stereoscopic effect of the stereoscopic captured image may be impaired.

  On the other hand, when the F number on the image side is relatively large, the light receiving area 109a itself becomes small, and the amount of received light is further impaired by the overlap with the dead zone 38 between the light receiving elements 32R and 32L. In particular, in a microscope, a relatively large F number is used to enlarge an object to be observed at a desired magnification. As a result, the light receiving area 109 becomes relatively small and the amount of received light decreases, but when the amount of received light is further impaired, the resolution of the stereoscopic image is lowered.

  In view of the above problems, the dead zone 38 in the present embodiment is configured as follows in order to minimize the loss of the amount of received light.

FIG. 6 is a diagram illustrating the dead zone 38 in the present embodiment. FIG. 6 shows the following dimensions in the cross-sectional view of the main part of the image sensor 20.
Distance a from the center of the micro lens 30 to the color filter 36 a
The thickness b of the color filter 36
Distance c from color filter 36 to light receiving surface of light receiving element 32
Width d of dead zone 38 in the X-axis direction
Length p of light receiving element 32 in the x-axis direction

  Here, FIG. 7 shows the correspondence between the magnification and numerical aperture (NA) of the objective lens 109, the adjustment magnification of the imaging device 10, the numerical aperture (NA) on the image side, and the F number on the image side. When the objective lens 109 of 5 to 100 times is used and the adjustment magnification of the imaging device 10 is 1 or 0.5 times in each case, the numerical aperture on the image side is 0.00095 (minimum) to 0.06. (Maximum), and accordingly, the F number is 8.3 (minimum) to 52.6 (maximum).

Then, when the F number is 8.3 (minimum), the light receiving region 109a of the light receiving element pair 32P is maximized. Therefore, at this time, the loss of the amount of received light can be suppressed by selecting the focal length f of the microlens 30 so that the radius of the light receiving region 109a approximates the length p of the light receiving element 32 in the x-axis direction. Such a condition is expressed by the following equation 1.
[Formula 1] 0.04 ≦ p / f ≦ 0.08
In particular, when p / f = 0.06, the radius of the light receiving region 109a is closest to the length p of the light receiving element 32 in the x-axis direction, so that the loss of received light amount can be minimized.

On the other hand, when the F number is 52.6 (maximum), the light receiving area 109a is minimum. Therefore, at this time, by selecting the width d of the dead band 38 and the length p of the light receiving element 32 in the x-axis direction so that the width d of the dead band 38 between the light receiving element pair 32P is smaller than the radius of the light receiving region 109a. The loss of the amount of received light can be suppressed. Such a condition is expressed by the following equation 2.
[Formula 2] 1/20 · p ≦ d ≦ 1/7 · p

The position of the exit pupil of the imaging lens 110 in the microscope apparatus 1 is set to infinity. Therefore, a preferable correspondence relationship between the focal length f of the microlens 30 and the shift amount Δz of the light receiving element 32 on the optical axis 300 with respect to the back focal point of the microlens 30 is expressed by the following Expression 3.
[Formula 3] −f / 10 ≦ Δz ≦ f / 10

  By configuring the focal length f of the microlens 30, the width d of the dead zone 38, and / or the length p of the light receiving element 32 in the x-axis direction so that any one or more of the above formulas 1 to 3 is satisfied. In order to obtain a desired enlargement ratio with the microscope apparatus 1, it is possible to suppress the loss of the amount of received light when using an arbitrary F-number on the image side. Therefore, it is possible to avoid the problem that the stereoscopic effect and resolution of the stereoscopic image due to the loss of the amount of received light are reduced.

  In addition, when the microlens 30 is configured by a spherical lens, the light receiving region 109a is smaller than when the microlens 30 is configured by a cylindrical lens. Therefore, the influence of the loss of the amount of light received by the dead zone 38 is larger than that of the cylindrical lens. Therefore, in the present embodiment, the loss of received light amount can be more advantageously suppressed in the case of the spherical lens than in the case of the cylindrical lens.

  Next, examples in the present embodiment will be described.

[First embodiment]
The first embodiment is a case where the light receiving element 32 is constituted by a CCD having wiring on its surface. In this case, the dead zone 38 is constituted by wiring, for example. In the first embodiment, the dimensions shown in FIG. 6 are as follows.
Distance a from the center of the micro lens 30 to the color filter 36: 146 μm
Color filter thickness b: 2 μm
Distance c from color filter 36 to light receiving surface of light receiving element 32: 2 μm
Dead zone 38 X-axis width d: 0.5 μm (one side width: 0.25 μm)
Length p of the light receiving element 32 in the x-axis direction: 5 μm

Further, the characteristics of the microlens 30 and the color filter 36 in the first embodiment are as follows.
Focal length fL of the micro lens 30: 100 μm
Curvature radius r of microlens 30: 50 μm
Refractive index n1: 1.5 of the material of the microlens 30
Refractive index n2 of the color filter 36: 1.5
Refractive index n3 of the medium (SiO2) between the color filter 36 and the light receiving element 32: 1.46

  In the first embodiment, when the F number of the objective lens 109 is 8.3, the size of the light receiving region 109a is 12 μm in diameter (6 μm in radius). The ratio of the amount of light lost due to the incident on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 16.4%.

  In the first example, when the F number of the objective lens 109 is 52.6, the size of the light receiving region 109a is 1.9 μm in diameter (0.95 μm in radius). At this time, the ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 33%.

[Second Embodiment]
The second embodiment is a case where the light receiving element 32 is constituted by a backside wiring type CMOS. In this case, the dead zone 38 is composed of a light shielding member formed into a flat film. In the second embodiment, the dimensions shown in FIG. 6 are as follows.
Distance from the center of the micro lens 30 to the color filter 36 a: 71 μm
Color filter thickness b: 2 μm
Distance c from color filter 36 to light receiving surface of light receiving element 32: 2 μm
Dead zone 38 X-axis width d: 0.2 μm (width on one side: 0.1 μm)
Length p of the light receiving element 32 in the x-axis direction: 3 μm

Further, the characteristics of the microlens 30 and the color filter 36 in the second embodiment are as follows.
Focal length fL of microlens 30: 50 μm
Curvature radius r of microlens 30: 25 μm
Refractive index n1: 1.5 of the material of the microlens 30
Refractive index n2 of the color filter 36: 1.5
Refractive index n3 of the medium (SiO2) between the color filter 36 and the light receiving element 32: 1.5

  In the second embodiment, when the F number of the objective lens 109 is 8.3, the size of the light receiving region 109a is 6 μm in diameter (3 μm in radius). The ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 4.3%.

  In the second embodiment, when the F number of the objective lens 109 is 52.6, the size of the light receiving region 109a is 0.95 μm in diameter (0.475 μm in radius). At this time, the ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 26.6%.

[Third embodiment]
8 and 9 are diagrams showing the configuration of the third embodiment. FIG. 8 is a schematic cross-sectional view of the entire image sensor 20, and FIG. 9 is a schematic cross-sectional view of the main part of the image sensor 20. In the third embodiment, a Si substrate 71 provided with a light receiving element 32 is covered with a microlens array 72 provided with a microlens 30, and the microlens array is supported by a support member such as a support 74 provided on the Si substrate. Configured as follows. In this case, the microlens 30 to the color filter 36 are filled with air. According to this manufacturing method, even if an existing microlens array is used, the distance between the microlens 30 and the color filter 36 can be easily adjusted by adjusting the support member.

In the third embodiment, the dimensions shown in FIG. 9 are as follows.
Microlens thickness t: 30 μm
Distance from the bottom surface of the microlens to the color filter 36 a: 96.6 μm
Color filter thickness b: 2 μm
Distance c from color filter 36 to light receiving surface of light receiving element 32: 2 μm

Dead zone 38 X-axis width d: 0.7 μm (one side width: 0.35 μm)
Length p of the light receiving element 32 in the x-axis direction: 8 μm

Further, the characteristics of the microlens 30 and the color filter 36 in the third embodiment are as follows.
Focal length fL of the micro lens 30: 125 μm
The radius of curvature r of the microlens 30 is 62.5 μm.
Refractive index n1: 1.5 of the material of the microlens 30
Refractive index n2 of the color filter 36: 1.5
Refractive index n3 of the medium (SiO2) between the color filter 36 and the light receiving element 32: 1.46

  In the third embodiment, when the F number of the objective lens 109 is 8.3, the size of the light receiving region 109a is 15 μm in diameter (7.5 μm in radius). The ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 6%.

  In the third embodiment, when the F number of the objective lens 109 is 52.6, the size of the light receiving region 109a is 2.38 μm in diameter (radius 1.19 μm). At this time, the ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 37%.

[Fourth embodiment]
FIG. 10 shows a light receiving element pair 32P of the fourth embodiment. In the fourth embodiment, the dead zone 38 is also provided between the light receiving elements 32 in the column direction, that is, in the Y-axis direction on the XY plane. In this case, when the F number is small and therefore the light receiving region 109 is large, the amount of light received is also lost by the dead zone 38 provided between the light receiving elements 32 in the Y-axis direction. The fourth embodiment takes this into consideration.

In the fourth embodiment, the dimensions shown in FIG. 6 are as follows (the same as the first embodiment).
Distance a from the center of the micro lens 30 to the color filter 36: 146 μm
Color filter thickness b: 2 μm
Distance c from color filter 36 to light receiving surface of light receiving element 32: 2 μm
Dead zone 38 X-axis width d: 0.5 μm (one side width: 0.25 μm)
Length p of the light receiving element 32 in the x-axis direction: 5 μm
In the fourth embodiment, the width d of the dead zone 38 in the Y-axis direction is the same.

Further, the characteristics of the microlens 30 and the color filter 36 in the fourth embodiment are as follows, as in the first embodiment.
Focal length fL of the micro lens 30: 100 μm
Curvature radius r of microlens 30: 50 μm
Refractive index n1: 1.5 of the material of the microlens 30
Refractive index n2 of the color filter 36: 1.5
Refractive index n3 of the medium (SiO2) between the color filter 36 and the light receiving element 32: 1.46

  In the fourth embodiment, when the F number of the objective lens 109 is 8.3, the size of the light receiving region 109a is 12 μm in diameter (6 μm in radius). The ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 20.4%. Note that when compared with the first embodiment, the fourth embodiment has the dead zone 38 between the light receiving elements 32 in the Y-axis direction, so that the ratio of the lost light amount is larger than that of the first embodiment.

  In the fourth embodiment, when the F number of the objective lens 109 is 52.6, the size of the light receiving region 109a is 1.9 μm in diameter (0.95 μm in radius). At this time, the ratio of the amount of light lost due to incidence on the dead zone 38 out of the amount of light incident on the microlens 30 corresponding to one picture element (light receiving element pair 32P) is suppressed to about 42.7%.

  As described above, according to the present embodiment, in order to obtain a desired enlargement ratio in the microscope apparatus 1, even if an arbitrary F-number on the image side is used, loss of received light amount can be suppressed. Therefore, it is possible to avoid the problem that the stereoscopic effect and resolution of the stereoscopic image due to the loss of the amount of received light are reduced.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each means, each step, etc. can be rearranged so that there is no logical contradiction, and a plurality of means, steps, etc. can be combined or divided into one. .

10: Image pickup device 20: Image pickup device 30: Micro lens 32: Light receiving device 38: Dead zone

Claims (5)

A pair of light receiving elements arranged for each lens arranged in a matrix and receiving light from a subject, and one light receiving element of the pair of light receiving elements has a parallax for displaying a stereoscopic image of the subject. A pixel signal that constitutes one of the captured image pairs, and the other light receiving element in the row direction of the light receiving element pair outputs a pixel signal that constitutes the other of the captured image pairs. An element pair;
A dead zone provided between the light receiving element pair so as to separate the light receiving element pair in the row direction,
When the length in the row direction of the light receiving element pair is p and the width in the row direction of the dead zone is d,
0.04 ≦ p / f ≦ 0.08
An image sensor characterized by being. In claim 1,
The focal length of the lens is f,
When the shift amount of the light receiving element from the rear focal point of the lens in the optical axis direction of the light from the subject is Δz,
−f / 10 ≦ Δz ≦ f / 10
An image sensor characterized by being. 3. The method according to claim 1, further comprising 1/20 · p ≦ d ≦ 1/7 · p.
An image sensor characterized by being. In any one of Claims 1 thru | or 3,
The lens has a curved surface to be pointed,
Image sensor. A microscope apparatus comprising the imaging device according to claim 1, wherein the imaging device captures an enlarged image of the object to be observed.

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