JP6772548B2 - Imaging equipment and imaging system - Google Patents

Description

The present invention relates to an imaging device and an imaging system.

A "image of each lens of a subject" formed by a lens array in which a plurality of lenses are arranged is formed as a "compound eye image" on the light receiving surface of an image sensor common to the plurality of lenses, and the compound eye image is imaged by the image sensor. Various image pickup devices are known.
The "subject image by one lens" that constitutes the compound eye image formed on the light receiving surface is called the "individual eye image", and the area assigned to each individual eye image on the light receiving surface is the "individual eye area". Is called. That is, one individual eye image is formed for each individual eye region on the light receiving surface, and a compound eye image is formed as a set of individual eye images.
When a compound eye image is imaged for the same subject, the individual eye images constituting the compound eye image are slightly different from each other, and the amount of information obtained about the subject is larger than that when a single image of the subject is imaged. Therefore, for example, a compound eye image can be combined to obtain a "subject image with high resolution", and a spectroscopic filter can be used to obtain individual eye images having different colors from each other to obtain a compound eye image. A "subject image with excellent color reproducibility" can be obtained as a composite image of the individual eye image.

Examples of an image pickup apparatus that captures a compound eye image with an image pickup device include those described in Patent Documents 1 and 2.

An object of the present invention is the realization of a novel imaging device capable of acquiring image signals corresponding to a plurality of individual eye images forming a compound eye image for the same subject.

In the image pickup apparatus of the present invention, the image of the subject by the M lenses of the lens array in which the M (> 1) lenses are arranged is displayed on the light receiving surface of the image pickup element common to the M lenses. An imaging device that forms an image as an individual-eye image and acquires an image signal corresponding to the M individual-eye images, which is arranged between the lens array and the light-receiving surface and is arranged from the M lenses. A transmission spectroscopic filter means having one or more transmission spectroscopic filters that disperse light directed to a light receiving surface, and one or more absorption spectroscopic filters arranged between the lens array and the transmission spectroscopic filter means. The transmissive spectroscopic filter means transmits light having a transmission band I of one or more types for each of the M lenses , and the wavelength band is a non-transmission band I. The absorption type spectroscopic filter means transmits light in a transmission band II whose wavelength band is at least partially shared with the transmission band I for each of the M lenses, and the wavelength band is the non-transmissive light. It absorbs light in the non-transmissive band II, which has at least a part in common with the transmitted band I.

According to the present invention, it is possible to realize a novel imaging device capable of acquiring image signals corresponding to a plurality of individual eye images forming a compound eye image for the same subject.

It is a figure which shows the imaging state of the imaging apparatus as an explanatory diagram. It is a figure for demonstrating the reduction of stray light. It is a figure explaining one embodiment of the image pickup apparatus. It is a figure for demonstrating the lens array, the absorption type spectroscopic filter, the transmission type spectroscopic filter, and the image pickup element in the image pickup apparatus of FIG. It is a figure for demonstrating an image signal acquired by an image pickup device when light from a subject is imaged on a light receiving surface of an image pickup device through a lens, an absorption type spectroscopic filter, and a transmission type spectroscopic filter. It is a figure for demonstrating a specific example 1. It is a figure for demonstrating the specific example 2. It is a figure for demonstrating the specific example 3. It is a figure for demonstrating another embodiment of the image pickup apparatus. It is a figure which shows the example of another embodiment of the image pickup apparatus. It is a figure which shows another embodiment of the image pickup apparatus. It is a figure for demonstrating one embodiment of the image pickup system.

Hereinafter, terms and the like will be described prior to the description of the embodiments of the invention.
In the imaging apparatus of the present invention, two types of spectroscopic filter means, that is, a transmission type spectroscopic filter means and an absorption type spectroscopic filter means are used. The transmissive spectroscopic filter means is composed of "one or more transmissive spectroscopic filters", and the absorption spectroscopic filter means is composed of "one or more absorption spectroscopic filters".
The transmission type spectroscopic filter transmits "light having a wavelength in a certain wavelength band" set by design, and reflects light having a wavelength other than this wavelength band. The wavelength band through which light is transmitted is referred to as a "passband", but in the present invention, it is referred to as a "passband I" in order to clarify that it is a transmission band of a transmission type spectroscopic filter. Further, light having a wavelength other than the transmission band I is reflected by the transmission type spectroscopic filter. Although the reflectance is not exactly 100%, the transmittance of light having a wavelength other than the transmission band I is "substantially 0", and the light having this wavelength does not pass through the transmissive spectroscopic filter.
Therefore, the wavelength band other than the transmission band I in the transmission type spectroscopic filter is called "non-transmission band I". These "transmission band I and non-transmission band I" are defined as "similar to the above" even when the transmission type spectroscopic filter means is composed of a plurality of transmission type spectroscopic filters.

The absorption type spectroscopic filter transmits "light having a wavelength in a certain wavelength band" set by design, and absorbs light having a wavelength other than this wavelength band. The wavelength band through which light is transmitted is the "passband", but is referred to as the "passband II" in order to clarify that it is the transmission band of the absorption type spectroscopic filter. Further, light having a wavelength other than the transmission band II is absorbed by the absorption type spectroscopic filter and is not transmitted. In this case as well, the transmittance is "substantially 0". The wavelength band other than the transmission band II in the absorption type spectroscopic filter is called "non-transmission band II".
These "transmission band II and non-transmission band II" are also defined as "similar to the above" when the absorption type spectroscopic filter means is composed of a plurality of absorption type spectroscopic filters.

In the following, in each of the above spectroscopic filter means, the spectroscopic filter means composed of only one spectroscopic filter is simply referred to as a transmission type spectroscopic filter and an absorption type spectroscopic filter, and is composed of a plurality of spectroscopic filters. Those are referred to as transmission type spectroscopic filter means and absorption type spectroscopic filter means.

See FIG.
FIG. 1 shows an imaging state of an imaging device that acquires an image signal IMS corresponding to the subject 0 by forming an image of the subject 0 on the light receiving surface of the image sensor 3 with the lens 1. For the sake of simplicity, the lens 1 is single. In FIG. 1, reference numeral 2 indicates a transmission type spectroscopic filter means.
The surface of the image sensor 3 facing the transmissive spectroscopic filter means 2 is the “light receiving surface”.
When the object light from the subject 0 passes through the lens 1, it becomes "imaging light", passes through the transmissive spectroscopic filter means 2, and forms a subject image Im on the light receiving surface of the image sensor 3.
The transmission type spectroscopic filter means 2 is assumed to be composed of "one transmission type spectroscopic filter", and will be simply referred to as a transmission type spectroscopic filter 2 below.

The transmission type spectroscopic filter 2 has a “transmission band I” of a specific wavelength band and a “non-transmission band I” which is a wavelength band other than the transmission band I.
In general, the transmittance in the "transmission band I" of the transmission type spectroscopic filter is not uniform and has wavelength dependence. That is, even light having a wavelength within the transmission band I is partially "reflected" unless the transmittance for the light having this wavelength is 100%.

In FIG. 1, reference numerals LR1 and LR2 indicate light reflected by the “transmissive spectroscopic filter 2”. The light LR1 and the light LR2, together with the light contained in the non-transmissive band I of the transmissive spectroscopic filter 2, "light having a wavelength in the transmissive band I and reflected by the transmissive spectroscopic filter 2 as described above" as described above. Also exists.

The light LR1 and the light LR2 are incident on the lens 1, and a part of the light is reflected by the lens 1 and is incident on the transmission type spectroscopic filter 2. The light reflected by the lens 1 and incident on the transmissive spectroscopic filter 2 in this way is referred to as "re-incident light LR1 and LR2" for convenience. When referring to "light reflected by the transmissive spectroscopic filter 2 and incident on the lens 1," they are referred to as light LR1 and light LR2 as described above.

The re-incident light LR1 and LR2 include a part of the light of the non-transmissive band I and the light of the transmitted band I. Of the reincident light LR1 and LR2, the light having a wavelength within the transmission band I is transmitted through the transmission type spectroscopic filter 2 to the image sensor 3 side. The reincident light LR1 that has passed through the transmission type spectroscopic filter 2 is incident on the position Ig on the light receiving surface.
Further, the re-incident light LR2 is reflected by the inner wall of the housing 4 that holds the optical system and is incident on the position If on the light receiving surface. The position Ig and the position If where the re-incident light LR1 and the re-incident light LR2 are incident are originally "positions where the light should not be incident", and when the light is incident at such a position, it becomes noise with respect to the subject image Im.
Light that is directly incident on the position Ig on the light receiving surface via the transmissive spectroscopic filter 2 like the reincident light LR1 is called "ghost light", and like the reincident light LR2, a casing outside the optical system. The light incident on the position If on the light receiving surface via the body 4 or the like is called "flare light", and the combination of ghost light and flare light is called "stray light".

Since the stray light reaches the light receiving surface of the image sensor regardless of the subject, an error with respect to the true spectral information of the subject (difference between the spectral information of the subject that should be originally acquired and the spectral information of the subject that is actually acquired). ) Increases, and the image quality of the reconstructed subject image deteriorates.
In the image pickup apparatus of the present invention, the influence of such stray light can be effectively reduced.

The principle of reducing the influence of stray light will be briefly described with reference to FIG.
FIG. 2 is an explanatory diagram in the case of "reducing stray light" in the example shown as an explanatory diagram in FIG. 1, and those that are not considered to be confused are designated by the same reference numerals as those in FIG.
In FIG. 2, reference numeral Lt indicates light incident on the lens 1. Reference numeral 2 indicates a transmission type spectroscopic filter, and reference numeral 5 indicates an absorption type spectroscopic filter.
The total amount of incident light Lt is set to "L", the transmissive spectroscopic filter 2 transmits the incident light L1 at a transmittance of f (0 <f <1), and the absorption spectroscopic filter 5 transmits the incident light L1. It is assumed that Lt is absorbed at an absorption rate of "ab (0 <ab <1)".

FIG. 2A-1 shows a state in which the light Lt passes through the lens 1 and is incident on the transmission type spectroscopic filter 2, and the transmitted light component reaches the light receiving surface of the image pickup device 3. In FIG. 2A-1, a part of the light Lt incident on the transmissive spectroscopic filter 2 is reflected and becomes an optical LR and is incident on the lens 1. As described above, the light LR incident on the lens 1 is "stray light".
Since the transmittance of the transmissive spectroscopic filter 2 is f (0 <f <1), the ratio of reflected light is (1-f), and the amount of light LR is as shown in FIG. 2 (a-2). Total light intensity: Product of L and (1-f): {L × (1-f)}.

FIG. 2B-1 is an example of the case of the present invention, in which the absorption type spectroscopic filter 5 is arranged between the lens 1 and the transmission type spectroscopic filter 2.
An "absorption-type spectroscopic filter" is known to have a structure in which an absorber is mixed with glass.
When the light Lt passes through the lens 1 and is incident on the absorption spectroscopic filter 5, a part of the light Lt is absorbed by the absorption spectroscopic filter 5 and the rest is incident on the transmission spectroscopic filter 2. The light incident on the transmissive spectroscopic filter 2 is partially absorbed by the absorption spectroscopic filter 5 and the amount of light is "L × ab". Therefore, when reflected by the transmissive spectroscopic filter 2, the reflected light is reflected. The amount of light of is "L × ab × (f-1).

The light LR0 in which the reflected light has passed through the absorption spectroscopic filter 5 again is partially absorbed again by the absorption spectroscopic filter, and the amount of the light is “L × (ab) ² ×” as shown in FIG. 2 (b-2). (F-1) ”.

That is, the amount of light of the light LR0 is reduced by "(ab) ² " times as much as when the absorption type spectroscopic filter 5 is not used (FIG. 2 (a-2)), and the influence as stray light is effectively reduced. To.

Hereinafter, embodiments will be described.
FIG. 3 is a diagram showing one embodiment of the imaging device as an explanatory diagram.
In FIG. 3, reference numeral 01 is “subject”, reference numeral 10 is “individual lenses constituting the lens array”, reference numeral 50 is “absorption-type spectral filter”, reference numeral 20 is “transmission-type spectral filter”, and reference numeral 30 is “light receiving”. "Element" and reference numeral 40 indicate "a housing for accommodating an optical system portion and an imaging element", respectively.

The lens array is an array in which a plurality of (M) lenses that are optically equivalent are arranged.
In the following description, the number of lenses 10 constituting the lens array will be described as 4 (M = 4), but the number of lenses constituting the lens array is not limited to this. It can be set as appropriate even when M = 4.

Specific examples other than M = 4 include "an array of 16 lenses (M = 16) in 4 rows and 4 columns". The arrangement of the lenses is not limited to a square matrix, and in the above case, various arrangements such as an arrangement of "2 rows and 8 columns" are possible depending on the number of lenses.

As the size of each lens, a lens having a diameter of about 4 mm to 20 mm can be exemplified as a suitable example, but of course, the size is not limited to this.

The absorption spectroscopic filter 50 is an example of an absorption spectroscopic filter means composed of one absorption spectroscopic filter. The transmissive spectroscopic filter 20 is also an example of a transmissive spectroscopic filter means composed of one transmissive spectroscopic filter.

The image pickup element 30 is common to a plurality of lenses (four in the example in the description) constituting the lens array, and the light receiving surface is directed toward the transmission type spectroscopic filter 20.
FIG. 4 is a diagram for explaining the lens array, the absorption type spectroscopic filter 50, the transmission type spectroscopic filter 20, and the image pickup element 30 in the image pickup apparatus shown in FIG. 3, and these are viewed from the optical axis direction of each lens in the lens array. Shows the state.
The light receiving surfaces of the lens array LA, the absorption spectroscopic filter 50, the transmissive spectroscopic filter 20, and the image sensor 30 are all orthogonal to the optical axis of each lens of the lens array.

As shown in FIG. 4A, the lens array LA is a lens array LA in which four lenses 10A, 10B, 10C, and 10D are "arranged in two rows and two columns and integrated".
The absorption type spectroscopic filter 50 has absorption filter regions 50A to 50D corresponding to each lens 10A to 10D in the lens array LA on a one-to-one basis. The transmission type spectroscopic filter 20 also has transmission filter regions 20A to 20D corresponding to the individual lenses 10A to 10D in the lens array LA on a one-to-one basis.
The light receiving surface of the image sensor 30 has four light receiving regions 30A to 30D, and these light receiving regions correspond one-to-one with each of the lenses 10A to 10D.

That is, the lens 10A in the lens array LA corresponds to the "absorption filter region 50A, the transmission filter region 20A, and the light receiving region 30A", and the lens 10B corresponds to the "absorption filter region 50B, the transmission filter region 20B, and the light receiving region 30B". To do. Further, the lens 10C in the lens array LA corresponds to the "absorption filter region 50C, the transmission filter region 20C, the light receiving region 30C", and the lens 10D corresponds to the "absorption filter region 50D, the transmission filter region 20D, the light receiving region 30D". To do.
Therefore, when the object light from the subject 01 enters each lens of the lens array LA, it sequentially passes through the absorption filter region and the transmission filter region corresponding to one-to-one with these lenses, and the imaging action of each lens is performed. As a result, an image is formed as a subject image in the corresponding light receiving region.
FIG. 4D shows a state in which the image of the subject 01 is formed as an inverted image in each of the four light receiving regions 30A to 30D. These four subject images constitute a "compound eye image".

As described above, the "subject image by one lens" that constitutes the compound eye image formed on the light receiving surface is called the "individual eye image", and the area allocated to each individual eye image on the light receiving surface is It is called the "individual eye area". Therefore, each of the light receiving regions 30A to 30D is an "individual eye region", and each of the subject images individually imaged in these individual eye regions is an "individual eye image".

When the light from the subject becomes an imaged luminous flux by the lens and is imaged on the light receiving surface of the image pickup device through the absorption type spectroscopic filter and the transmission type spectroscopic filter, the image signal acquired by the image pickup device is referred to with reference to FIG. explain. FIG. 5 relates to, for example, an individual eye image formed in the individual eye region 30A shown in FIG. 4 (d).
At this time, the lens 10A of the lens array LA, the absorption filter region 50A, and the transmission filter region 20A are involved in the imaging of the individual eye image. For the sake of simplicity, it is assumed that the lens 10A does not absorb light.
The left figure (light rays from the subject) of FIG. 5 shows the spectral information of the object light from the subject, and the amount of light with respect to the wavelength shown on the horizontal axis is shown on the vertical axis in arbitrary units.
The “absorption-type spectroscopic filter” in FIG. 5 shows the spectral transmittance of the absorption filter region 50A. The "absorption characteristic" of the absorption type spectroscopic filter 50A is obtained by subtracting this spectral transmittance (%) from 100%.
The “transmission type spectroscopic filter” in FIG. 5 shows the spectral transmittance of the transmission filter region 20A, that is, the “transmission characteristic”.
The “sensor sensitivity” in FIG. 5 indicates the spectral sensitivity of the image pickup device (since the image pickup device is common to the lenses 10A to 10D, the spectral sensitivity is common to the individual eye regions 30A to 30D) in arbitrary units. ing.

When light having spectral information shown in "light rays from the subject" from the subject forms a subject image in the light receiving area 30A through the absorption filter area 50A and the transmission filter area 20A, it is output from the light receiving area 30A. sensor response value "," light from the object "in FIG. 5," absorption spectral filter ", given by" transmission spectral filter "," integration value obtained by integrating the "wavelength band product of sensor sensitivity". "
The same applies to the individual eye images formed in the other light receiving regions 30B, 30C, and 30D.
In the "absorption-type spectroscopic filter" shown in FIG. 5, the wavelength band having a transmittance of 0% is the "non-transmissive band II".
The wavelength band other than the non-transmissive band II is the “transmissive band II”.
In the "transmission type spectroscopic filter", the wavelength band having a transmittance of 0% is the "non-transmission band I", and the wavelength band having a transmittance of not 0% is the "transmission band I".
In the above description, "the transmittance is 0%" includes not only the case where the transmittance is strictly 0% but also the case where the transmittance is substantially 0%.

The transmission band II in the absorption type spectroscopic filter shown in FIG. 5 includes the “transmission band I in the transmission type spectroscopic filter”. Therefore, among the object light from the subject, the light transmitted through the absorption type spectroscopic filter can be transmitted through the transmission type spectroscopic filter and imaged on the light receiving surface.
The transmission band I in the transmission type spectroscopic filter does not necessarily have to be “included in the transmission band II in the absorption type spectroscopy filter” as in the above example, but the light transmitted through the absorption type spectroscopy filter and the transmission type spectroscopy filter is received. Needless to say, in order to be able to form a subject image on a surface, the transmission band II of the absorption type spectroscopic filter and the transmission band I of the transmission type spectroscopic filter must have " wavelength bands common to each other".

That is, the absorption type spectroscopic filter transmits "light in the transmission band I of the transmission type spectroscopic filter". When the entire transmission band I of the transmission type spectroscopic filter is not included in the "transmission band II of the absorption type spectral filter", the " wavelength band common to the transmission band II of the absorption type spectral filter" in the transmission band I ". Light reaches the light receiving surface.

That is, the absorption type spectroscopic filter has a transmission band II common to the wavelength band of the transmission band I of the transmission type spectroscopic filter, and has a non-transmission band II common to the non-transmission band I of the transmission type spectroscopic filter means.
Transmission band II absorptive spectral filter and the transmission band I of the transmissive spectral filter is a "common", the transmission band I (or transmission band II) is a wavelength band overlaps with a transmission band II (or transmission band I) In some cases, one wavelength band may be included in the other wavelength band. The same applies when the non-transmissive band I and the non-transmissive band II are common.

In the example in the explanation, the lens array LA has four lenses, and the absorption filter region, the transmission filter region, and the light receiving region (individual eye region) correspond one-to-one with each of the four lenses. However, various combinations are possible as the spectral characteristics (spectral transmittance characteristics) in the absorption filter region and the transmission filter region.

For example, the absorption filter regions 50A to 50D may have "same spectral transmittance characteristics" with each other, and the transmission filter regions 20A to 20D may also have "same spectral transmittance characteristics" with each other. The spectral transmittance characteristics of 50A to 50D do not have to be the same as each other, and the spectral transmittance characteristics of the transmission filter regions 20A to 20D do not have to be the same as each other.

For example, the absorption filter regions 50A and 50D are paired to have the same spectral transmittance characteristics, and the absorption filter regions 50B and 50C are paired to have the same spectral transmittance characteristics (the spectral transmittance characteristics of the absorption filter regions 10A and 10D). May have different). Alternatively, the absorption filter regions 50A to 50D may have different spectral transmittance characteristics from each other, and the transmission filter regions 20A to 20D may also have different spectral transmittance characteristics from each other.
In this way, when the absorption type spectroscopic filter and the plurality of filter regions of the transmission type spectroscopic filter do not have the same spectral transmittance characteristics, the filter regions having individual spectral transmittance characteristics are individually created. , Each spectroscopic filter can be configured by joining and integrating these.

A specific example will be described below.
"Specific example 1"
As a specific example 1, the absorption filter regions 50A to 50D have the same spectral transmittance characteristics (same transmission band I, the same non-transmission band I), and the transmission filter regions 20A to 20D also have the same spectral transmittance characteristics (same transmission band I). The case of having the same transmission band II and the same non-transmission band II) will be described.
See FIG.
The "same spectral transmittance characteristics" of the absorption filter regions 50A to 50D are as shown in "# 2" in the figure, and the "same spectral transmittance characteristics" of the transmission filter regions 20A to 20D are as shown in "# 1" in the figure. It is assumed that it is like. In this case, the "spectral transmittance characteristic of the absorption type spectroscopic filter and the transmission type spectroscopic filter combined" is as shown in "# 3" of FIG.
That is, light (# 3) having a wavelength in the "common wavelength band" of the transmission band II ("# 2") of the absorption type spectroscopic filter 50 and the transmission band I ("# 1") of the transmission type spectroscopic filter 20. Reaches each individual eye region on the light receiving surface to form an individual eye image.

Light in the non-transmissive band I of the transmissive spectroscopic filter 20 and in the transmissive band II of the absorption spectroscopic filter 50 is transmitted through the absorption spectroscopic filter 50 when reflected by the transmissive spectroscopic filter 20, and is therefore referred to as "stray light". Become.

Light in the non-transmissive band I of the transmissive spectroscopic filter 20 and in the non-transmissive band II of the absorption spectroscopic filter 50 is reflected by the transmissive spectroscopic filter 20, but is absorbed by the absorption spectroscopic filter 50. It does not become.
That is, the light in the “non-transmissive band II of the absorption type spectroscopic filter 50” in the non-transmissive band I of the transmission type spectroscopic filter 20 is “absorbed” by the absorption type spectroscopic filter 50, so that the transmission type spectral filter 20 Stray light is suppressed and the influence of stray light is reduced as compared with the case of using only.

For example, when the spectral transmittances of the transmissive spectroscopic filter and the absorption spectroscopic filter are as shown in FIG. 6 spectral transmittances: # 1 and # 2, light having a wavelength of 400 nm has transmission band I and transmission band II. Since it is contained in, it passes through both the transmission type spectroscopic filter and the absorption type spectroscopic filter and reaches the image pickup element (# 3).
Light having a wavelength of 500 nm is included in the non-transmissive band I and is included in the transmission band II, so that it is reflected by the transmission spectroscopic filter and passes through the absorption spectroscopic filter to become stray light. Are both included in the non-transmissive band I and the non-transmissive band II, so that they are reflected by the transmissive spectroscopic filter, but are absorbed by the absorption spectroscopic filter and do not become stray light.

In this example, by arranging the absorption type spectroscopic filter 50, light having wavelengths of 600 nm and 700 nm, which becomes stray light when only the transmission type filter 20 is used, can be absorbed by the absorption type spectroscopic filter, and the stray light can be suppressed. it can.

Incidentally, when a transmission type spectroscopic filter and an absorption type spectroscopic filter having the spectral transmittance characteristics of “# 1 and # 2” in FIG. 6 are used, the “spectral information acquired by the image sensor” is the characteristic of FIG. It is the product of # 2 and # 2, and is information on the subject image formed by the spectral transmittance characteristic as shown in # 3 of FIG.

"Specific example 2"
FIG. 7 shows the case of the specific example 2 which is a modification of the specific example 1 described above, and the spectral transmittance characteristics: # 1 and # 2 are the spectral transmittances of the transmission type spectral filter and the absorption type spectral filter, respectively. Shows the characteristics. In this case, the transmission band I (# 1) of the transmission type spectroscopic filter is "not completely included" in the transmission band II (# 2) of the absorption type spectroscopy filter, but these transmission band I and transmission band II are Light having a "common wavelength band overlapping each other" and having a spectral transmittance characteristic: # 3 which is a product of these reaches the image pickup element and forms a subject image.
For example, light having a wavelength of 400 nm is reflected by the transmissive spectroscopic filter because it is in the non-transmissive band I (# 1) of the transmissive spectroscopic filter, but is in the non-transmissive band II (# 2) of the absorption spectroscopic filter. Therefore, it is absorbed by the absorption type spectroscopic filter and does not become stray light.

On the other hand, for example, light having a wavelength of 550 nm is reflected by the transmissive spectroscopic filter because it is light (# 1) in the non-transmissive band I for the transmissive spectroscopic filter, but is reflected by the transmissive spectroscopic filter. Since it is the light inside (# 2), it passes through the absorption type spectroscopic filter and becomes stray light.

That is, the light contained in the transmission band II at the spectral transmittance: # 1 is stray light in the non-transmissive band I at the spectral transmittance I: # 1, but the light is spectroscopic at the non-transmissive band I at the spectral transmittance: # 1. Transmittance: Light contained in the non-transmissive band II of # 2 does not become stray light.

By using a transmission type spectroscopic filter or an absorption type spectroscopic filter having spectral transmittance as shown in FIGS. 6 and 7 as in Specific Examples 1 and 2, it is possible to "completely prevent" the generation of stray light. Even if it is not present, the generation of stray light can be effectively reduced.

In the examples of FIGS. 6 and 7, as a method of more effectively reducing the generation of stray light, the upper limit wavelength of the transmission band II in the spectral transmittance (# 2) of the absorption type spectroscopic filter is set to the spectroscopy of the transmission type spectroscopic filter. It is conceivable to approach the upper limit wavelength in the transmittance (# 1).

The spectral transmittances shown in FIGS. 6 and 7: # 1 and # 2 are examples, and the desired spectral transmittance in the “overlapping portion of the transmission band of the transmission type spectral filter and the transmission band of the absorption type spectral filter”. It is only necessary to realize the above, and the present invention is not limited to FIGS. 6 and 7.

Above, the absorption filter regions 50A to 50D of the absorption type spectroscopic filter 50 have "same spectral transmittance characteristics (same non-transmissive band II, same transmission band II)", and the transmission filter of the transmission type spectral filter 20. The case where the regions 20A to 20D also have "same spectral transmittance characteristics (same transmission band I, same non-transmission band I)" has been described.
The case where the absorption filter regions 50A to 50D of the absorption type spectroscopic filter 50 have different spectral transmittance characteristics and the transmission filter regions 20A to 20D of the transmission type spectral filter 20 also have different spectral transmittance characteristics will be described below. To do.
"Specific example 3"
FIG. 8 shows an example of the spectral characteristics of the absorption filter region and the transmission filter region.

In FIG. 8, the spectral transmittance characteristic of the transmission filter region 20A is shown as “A2”, and the spectral transmittance characteristic of the absorption filter region 50A is shown as “A3”. Similarly, the spectral transmittance characteristic of the transmission filter region 20B is shown as "B2", the spectral transmittance characteristic of the absorption filter region 50B is shown as "B3", the spectral transmittance characteristic of the transmission filter region 20C is "C2", and the absorption filter region. The spectral transmittance characteristic of 50C is shown as "C3". Further, the spectral transmittance characteristic of the transmission filter region 20D is shown as "D2", and the spectral transmittance characteristic of the absorption filter region 50D is shown as "D3".
The spectral transmittance characteristic of FIG. 8: A2 is a spectral transmittance characteristic that transmits “mainly blue light”, and the spectral transmittance characteristic: B2 is a spectral transmittance characteristic that transmits “mainly green light”. Similarly, the spectral transmittance characteristic: C2 is a spectral transmittance characteristic that transmits "mainly red light", and the spectral transmittance characteristic: D2 is a spectral transmittance characteristic that transmits "mainly light in the near infrared region". ..

When a transmission type spectroscopic filter and an absorption type spectroscopic filter having such spectral transmittance characteristics are used, the colors of the subject images, which are individual eye images formed in the individual eye regions (light receiving regions) 30A to 30D, are different from each other. The so-called "multi-band spectral information" can be acquired, and a "subject image having excellent color reproducibility" can be obtained as a composite image of individual eye images of different colors.

Similar to the example described above, for each subject light imaged in each individual eye region, "light in the non-transmissive band I in the transmissive filter region and light in the non-transmissive band II in the corresponding absorption filter region" is selected as an absorption filter. Stray light can be reduced by absorbing in the area.
The spectral transmittances shown in FIG. 8: A2, B2, C2, D2, A3, B3, C3, and D3 are also examples, and are not limited to this characteristic.

FIG. 9 shows another embodiment example.
In FIG. 9, reference numerals 1A and 1B indicate two lenses adjacent to each other in the lens array. The lens 1A corresponds to the absorption filter region 5A of the absorption spectroscopic filter, the transmission filter region 2A of the transmission spectroscopic filter, and the individual eye region DMA which is the light receiving region in the image sensor 30. Similarly, the lens 1B corresponds to the absorption filter region 5B of the absorption spectroscopic filter, the transmission filter region 2B of the transmission spectroscopic filter, and the individual eye region DMB which is the light receiving region in the image sensor 30.
As shown in the figure, consider the case where the light L10 is incident on the lens 1A.
At this time, the wavelength of the light L10 may be included in the transmission band II of the absorption filter region 5A and may be included in the non-transmission band I of the transmission filter region 2A. In such a case, the light L10 transmitted through the lens 1A and the absorption filter region 5A is reflected by the transmission filter region 2A to become the reflected light L11, but the reflected light L11 is transmitted through the absorption filter region 5A to the lens 1A. It may be incident on the adjacent lens 1B.
Then, the reflected light L11 is reflected by the lens 1B to become the reflected light L12, and is incident on the absorption filter region 5B. At this time, if the transmission band II of the absorption filter region 5B includes the wavelength of the reflected light L12 in the wavelength band, the reflected light L12 passes through the absorption filter region 5B and is incident on the transmission filter region 2B. When the transmission band I of the transmission filter region 2B includes the wavelength of the reflected light L12, the reflected light L12 passes through the transmission filter region 2B and reaches the individual eye region DMB as ghost light. The reflected light L11 or L12 may also be reflected by the inner wall of the housing 40 or the like to become flare light, and may be incident on the individual eye region DMA or the individual eye region DMB. The light L10 incident on the lens 1A in this way may act as stray light on the “individual eye region DMB corresponding to the lens 1B” across the individual eye region.

In this case, if the wavelength of the light L10 is included in the non-transmissive band II of the absorption filter region 5B, the reflected light L11 is absorbed by the absorption filter region B5 and does not become stray light for the individual eye region DMB.
That is, if the non-transmissive band I of the transmission filter region 2A corresponding to the individual eye region DMA is the non-transmissive band II of the absorption filter region 5B corresponding to the individual eye region DMB, it is reflected by the transmission filter region 2A. Stray light that was not absorbed in the absorption filter region 5A can be absorbed in the absorption filter region 5B corresponding to the individual eye region DMB, and "stray light that straddles the individual eye region" can be suppressed.

For example, the spectral transmittance characteristics of the absorption filter region 5A and the transmission filter region 2A are "A3" and "A2" in FIG. 8, respectively, and the spectral transmittance characteristics of the absorption filter region 5B and the transmission filter region 2B are shown in FIG. 8, respectively. Consider the case where it is "D3" and "D2".
If the wavelength of the light L10 incident on the lens 1A is 400 nm, this light passes through the absorption filter region 5A and the transmission filter region 2A and reaches the individual eye region DMA.
However, when the wavelength of the light L10 is 500 nm, this light passes through the absorption filter region 5A and is reflected by the transmission filter region 2A to become stray light. When such stray light "crosses the individual eye region" and reaches the absorption filter region B5, the light of 500 nm is absorbed because it is contained in the non-transmissive band II of the absorption filter region 5B, and the stray light with respect to the individual eye region DMB. It does not become.

When the wavelengths of the light L10 are 600 nm and 700 nm, these wavelengths are included in the transmission band II of the absorption filter region 5B, but are included in the non-transmission band I of the absorption filter region 5A. Therefore, since it is absorbed by the absorption filter region 5A, it does not become stray light for both the individual eye region DMA and the individual eye region DMB.
In this way, "stray light that straddles the individual eye region" is suppressed.

FIG. 10 shows an example of another embodiment of the imaging device.
As in FIG. 3, reference numeral 10 indicates an individual lens constituting the lens array, reference numeral 30 indicates an image sensor, and reference numeral 40 indicates a housing.
In the imaging apparatus shown in FIG. 10, the absorption type spectroscopic filter means is composed of "n absorption type spectroscopic filters 50-1, ... 50-n", and the transmission type spectroscopic filter means is "m pieces of transmission type spectroscopic filter". It is composed of "20-1 ... 20-m".

In the example described above, the non-transmissive band I in the transmission filter region and the non-transmissive band II in the absorption filter region are both described as having "transmittance 0", but in an actual spectroscopic filter, the non-transmissive band And 雖 often have a "finite transmittance".
In such a case, if only one absorption type spectroscopic filter is used, the light reflected by the transmission type spectroscopic filter means tends to pass through the absorption type spectroscopic filter and become "stray light".

Therefore, as in the example of FIG. 10, if a plurality of (n) absorption type spectroscopic filters 50-1 ... 50-n are used, the light reflected by the transmission type spectroscopic filter means and incident on the absorption type spectroscopic filter means. Can be sufficiently absorbed, and the generation of stray light can be effectively reduced. When the absorption type spectroscopic filter means is composed of n absorption type spectroscopic filters, stray light is suppressed by 2n times as compared with the case where there is only one absorption type spectroscopic filter.

Further, even if there is a finite transmittance in the non-transmissive band I of one transmissive spectroscopic filter, as shown in FIG. 10, the transmissive spectroscopic filter means is used with m (≧ 2) transmissive spectroscopic filters. By configuring the structure, it is possible to effectively reduce the transmission of "light that should be reflected in the non-transmissive band I" to the image pickup element 30 side, and the subject image reaches the light receiving surface of the image pickup element 30. The wavelength band of the light to be imaged can be effectively brought close to the transmission band I.

In other words, in one transmission type spectroscopic filter or one absorption type spectroscopic filter, even if the non-transmission band has "finite transmittance", the transmission type spectroscopic transmission filter means or absorption in which a plurality of these are laminated. As the type spectroscopic filter means, the transmittance of the non-transmissive band I and the non-transmissive band II can be made substantially zero.

In FIG. 11, of the two absorption spectroscopic filters 50-A and 50-B constituting the absorption spectroscopic filter, the absorption spectroscopic filter 50-A is used for the optical axis of the lens array (each lens forming the lens array). An example of the form in which the lens is arranged at an angle with respect to the 10 optical axes) is shown.

When the absorption spectroscopic filter 50-A is tilted with respect to the optical axis of the lens array, the reflection direction of stray light changes and the amount of stray light reaching the image sensor 30 changes. Therefore, the shape of the lens 10 and the housing 40 Stray light can be suppressed by adjusting the "tilt angle with respect to the optical axis" of the absorption type spectroscopic filter according to the shape of.

FIG. 12 shows an embodiment of an “imaging system” using the imaging device of the present invention as an explanatory diagram.
The image pickup system includes an image pickup device 100 and an image processing means 200.
The image processing means 200 has a control unit 210 configured as a computer or the like and an image processing unit 220. As the image pickup apparatus 100, the one of the present invention, such as the embodiment of the above-described embodiment, can be appropriately used.
The control unit 210 controls the image pickup device 100 and the image processing unit 220. That is, the control unit 210 controls the image pickup device 100 to output an image signal IMS corresponding to "a compound eye image formed as a set of individual eye images of the subject on the light receiving surface of the image pickup element". The image signal IMS is input to the image processing unit 220, and the image processing unit 220 under the control of the control unit 210 performs "image processing such as formation of a composite image" and outputs it as output information OPI.

As described above, according to the present invention, the following novel imaging apparatus and imaging system can be realized.
[1]
The image of the subject (01) by the M lenses of the lens array (LA) in which the M (> 1) lenses (10) are arranged is received by the imaging element (30) common to the M lenses. An imaging device that forms an image on a surface as M individual eye images and acquires an image signal (IMS) corresponding to the M individual eye images, and is arranged between the lens array and the light receiving surface. Then, between the transmission type spectroscopic filter means (20) by one or more transmission type spectroscopic filters that disperse the light from the M lenses toward the light receiving surface, and the lens array and the transmission type spectroscopic filter means. It has an absorption type spectroscopic filter means (50) by one or more arranged absorption type spectroscopic filters, and the transmission type spectroscopic filter means (20) has one or more kinds of wavelength bands for each of the M lenses. The light of the transmission band I is transmitted, the light of the non-transmission band I is made non-transmissive, and the absorption type spectroscopic filter means (50) has the wavelength band of the transmission band I for each of the M lenses. An imaging device that transmits light in a transmission band II that is at least partly common and absorbs light in a non-transmission band II whose wavelength band is at least partly common to the non-transmission band I (FIGS. 3, 9, and 10). , FIG. 11).

[2]
In the imaging apparatus according to [1], the transmission type spectroscopic filter means has a common transmission band I for the M lenses, and the absorption type spectroscopic filter means has the same transmission band I for the M lenses. An imaging device having a common non-transmissive band II (FIGS. 6 and 7) .

[3]
In the imaging apparatus according to [1], the M individual eye regions (30A to 30D) corresponding to the M lenses are individually separated by light having different wavelength bands of N (M ≧ N ≧ 2). An imaging device (FIGS. 3 and 8) in which the spectral transmittance characteristics of the transmissive spectroscopic filter means and the absorption spectroscopic filter means are defined so as to be exposed to .

[4]
[3] In the imaging apparatus according to the above, the transmission filter region is an individual region of the transmission type spectroscopic filter means for different individual eye regions, and the absorption filter is an individual region of the absorption type spectroscopic filter means for different individual eye regions. When it is a region, the absorption filter region of the absorption type spectroscopic filter means is set so that the non-transmission band I of one of the transmission filter regions becomes the non-transmission band II of the other absorption filter region in different individual eye regions. An image pickup device having defined spectral transmittance characteristics (Fig. 9) .

[5]
In the imaging apparatus according to any one of [1] to [4], the transmission spectroscopic filter means is composed of two or more transmission spectroscopic filters (50-1, ... 50-n). Imaging device (Fig. 10) .

[6]
The imaging apparatus according to any one of [1] to [5], wherein the absorption spectral filter means, an imaging apparatus that is more configured two or more absorption spectral filter (Figure 10).

[7]
In the image pickup apparatus according to any one of [1] to [6], an image pickup device in which one or more absorption spectroscopic filters are arranged at an angle with respect to the optical axis of the lens array (FIG. 11) .

[8]
Image processing that performs image processing on the image sensor (100) according to any one of [1] to [7] and the image signal corresponding to the M individual eye images acquired by the image sensor. An image pickup system (FIG. 12) having means (200) .

Although the preferred embodiment of the invention has been described above, the present invention is not limited to the specific embodiment described above, and the invention described in the claims unless otherwise limited in the above description. Various modifications and changes are possible within the scope of the above.
For example, the absorption spectroscopic filter means may be arranged between the transmission spectroscopic filter means and the light receiving surface. Even in this way, the stray light directed toward the image sensor can be effectively absorbed and the influence of the stray light can be suppressed.

The effects described in the embodiments of the present invention merely list suitable effects arising from the invention, and the effects according to the invention are not limited to "the ones described in the embodiments".

01 Subject
10 Individual lenses that make up the lens array
20 Transmission type spectroscopic filter (transmission type spectroscopic filter means)
50 Absorption-type spectroscopic filter (absorption-type spectroscopic filter means)
LA lens array
Lenses that make up a 10A-10D lens array
Transmission filter area corresponding to 20A to 20D lenses 10A to 10D
Absorption filter area corresponding to 50A to 50D lenses 10A to 10D
30A to 30D Light receiving area (individual eye area) corresponding to lenses 10A to 10D

Japanese Unexamined Patent Publication No. 2011-182237 JP-A-2007-304525

Claims (8)

The image of the subject by the M lenses in the lens array in which M (> 1) lenses are arranged is formed as M individual eye images on the light receiving surface of the image sensor common to the M lenses. An image sensor that acquires image signals corresponding to the M individual eye images.
Transmission spectroscopic filter means by one or more transmissive spectroscopic filters arranged between the lens array and the light receiving surface to disperse light from the M lenses toward the light receiving surface.
It has an absorption type spectroscopic filter means by one or more absorption type spectroscopic filters arranged between the lens array and the transmission type spectroscopic filter means .
The transmissive spectroscopic filter means transmits light having a transmission band I having one or more kinds of wavelength bands for each of the M lenses , and makes light having a non-transmissive band I non-transmitting.
The absorption spectroscopic filter means transmits light in a transmission band II whose wavelength band is at least partially shared with the transmission band I for each of the M lenses, and has a wavelength band at least a part of the non-transmission band I. An imaging device that absorbs light in the non-transmissive band II that is common to all . The imaging device according to claim 1.
An imaging device in which the transmission type spectroscopic filter means has a common transmission band I for the M lenses, and the absorption type spectral filter means has a non-transmission band II common to the M lenses . The imaging device according to claim 1 .
The transmissive spectroscopic filter means and the absorption so that the M individual eye regions corresponding to the M lenses are individually exposed to light in different wavelength bands of N (M ≧ N ≧ 2). An imaging device in which the spectral transmittance characteristics of the type spectroscopic filter means are defined . The imaging device according to claim 3 .
When each of the regions for different individual eye regions of the transmission type spectroscopic filter means is a transmission filter region and each of the regions of the absorption type spectroscopic filter means for different individual eye regions is an absorption filter region, in different individual eye regions, An imaging device in which the spectral transmittance characteristics of the absorption filter region of the absorption type spectroscopic filter means are defined so that the non-transmissive band I of one of the transmission filter regions becomes the non-transmission band II of the other absorption filter region. .. In the imaging device according to any one of claims 1 to 4.
An imaging device in which the transmission spectroscopic filter means is composed of two or more transmission spectroscopic filters . In the imaging device according to any one of claims 1 to 5,
An imaging device in which the absorption spectroscopic filter means is composed of two or more absorption spectroscopic filters . In the imaging device according to any one of claims 1 to 6.
An imaging device in which one or more absorption spectroscopic filters are arranged at an angle with respect to the optical axis of the lens array . The imaging device according to any one of claims 1 to 7.
An imaging system having an image processing means for performing image processing on image signals corresponding to the M individual eye images acquired by the imaging device.

Images