JP2021021704A - Spectroscopic element, spectroscopic measurement device, image evaluation device, and image forming apparatus - Google Patents

Abstract

To provide a spectroscopic element that can simultaneously measure the spectral characteristics of a plurality of points, while reducing cost.SOLUTION: A spectroscopic element 30 has an area division unit 31 that includes a plurality of openings 32 arranged regularly and divides light incident from an object of measurement S by area with the openings 32; a spectroscopic unit 33 that divides the light passing through the openings 32; and a light receiving unit 34 that receives the light divided in the spectroscopic unit 33. When the incident angle of the light incident in the openings 32 is θ, the diameter of the openings 32 is φ, the interval between the adjacent openings 32 is l, and the distance between the area division unit 31 and light receiving unit 34 is d1, 2 d1 tanθ+φ≤l is satisfied.SELECTED DRAWING: Figure 1

Description

The present invention relates to a spectroscopic element, a spectroscopic measuring device, an image evaluation device, and an image forming device.

In an image forming apparatus for forming a color image on a recording medium such as paper, an image evaluation apparatus for measuring the color of the formed color image and performing color management to improve reproducibility and stability is known. There is.
In such an image evaluation device, it is necessary to accurately measure the color on the recording medium, and it is more desirable that a plurality of points such as a color chart can be measured at the same time. Therefore, a pinhole array in which light from a plurality of points to be measured is arranged in parallel, a spectroscopic element using a microlens array and an image sensor serving as a light receiving unit, and a plurality of points using such a spectroscopic element. There are known spectroscopic measuring devices (see, for example, Patent Documents 1, 2 and the like) that acquire the spectral characteristics of the above in parallel.
However, when a spectroscopic element incorporating such a microlens array is used, although the optical performance is improved, there is a problem of high cost.

Further, in the configuration in which the microlens array is simply removed from the spectroscopic element, not only a sufficient amount of light cannot be obtained, but also the incident light spreads according to the angle of incidence on the pinhole array, so that the incident light is incident on the image sensor. There is also concern about the problem of overlapping lights.
In order to eliminate such concerns, for example, the light projected on the image sensor may be designed to have a large interval, but it becomes difficult to reduce the size and increase the resolution, so that the spectral performance is maintained. There was a problem that it was difficult to reduce the cost.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a spectroscopic element capable of simultaneously measuring the spectral characteristics of a plurality of points while reducing the cost.

In order to solve the above-mentioned problems, the spectroscopic element of the present invention includes a plurality of regularly arranged openings, a region dividing portion that divides the light incident from the measurement target into regions by the openings, and passes through the openings. It has a spectroscopic unit that disperses the light and a light receiving portion that receives the light dispersed in the spectroscopic unit, and the incident angle of the light incident on the aperture: θ, the diameter of the aperture: φ, and adjacent to each other. When the distance between the matching openings is l and the distance between the region dividing portion and the light receiving portion is d ₁ , 2 · d · tan θ + φ ≦ l is satisfied.

According to the present invention, it is possible to measure the spectral characteristics of a plurality of points at the same time while reducing the cost.

It is a figure which shows an example of the whole structure of the image forming apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the structure of the image evaluation apparatus provided in the image forming apparatus shown in FIG. It is a figure which shows an example of the structure of the spectroscopic element shown in FIG. It is a figure which shows an example of the projection of the primary diffracted light in a light receiving part. It is a figure which shows an example of the projection of the primary diffracted light when the pitch of a pinhole is made excessively narrow. It is a figure which shows an example of the locus of the light flux transmitted through the inside of a spectroscopic element. It is a figure which shows an example of the structure of the spectroscopic element shown in the 2nd Embodiment. It is a figure which shows an example of the structure of the spectroscopic element shown in the 3rd Embodiment. It is a figure which shows an example of the projection of the primary diffracted light when the spectroscopic element of the 3rd Embodiment is used. It is a figure which shows an example of the structure of the spectroscopic element shown in 4th Embodiment. It is a figure which shows an example of the projection of the primary diffracted light when the spectroscopic element of 4th Embodiment is used. It is a figure which shows the comparative example of the structure of the image evaluation apparatus shown in FIG. It is a figure which shows the comparative example of the structure of the spectroscopic element shown in FIG.

As an example of the embodiment of the present invention, an image forming apparatus 101 for forming an image on a sheet S serving as a recording medium and a color image provided on the image forming apparatus 101 are measured and color management is performed. The schematic configuration of the image evaluation device 102 for improving the reproducibility and stability is shown.

As shown in FIG. 1, the image forming apparatus 101 includes an image evaluation apparatus 102, a paper feeding unit 103, a control unit 104, a scanning optical system 105, a photoconductor 106, and an intermediate transfer belt 107 which is an intermediate transfer body. And have.
The image forming apparatus 101 is also provided at the rearmost end of a conveying path 110 composed of a fixing portion 108 for fixing a toner image formed on the sheet S as an image and a roller or the like for conveying the sheet S. It has a paper ejection roller 109 for ejecting the paper.
In the description of the present embodiment, only the case where the image forming apparatus 101 operates as an electrophotographic full-color image forming apparatus that reads image information and forms an image on the surface of the sheet S will be described, but is limited to such a configuration. It's not something. For example, the configuration may be such that an image sent from another terminal is formed on the surface of the sheet S, or an inkjet method or the like may be used, and the present invention is not limited to a specific image forming method. ..

In the image forming apparatus 101, the paper feeding unit 103 has a paper feeding tray 103a and a paper feeding roller 103b for loading and storing the sheet S.
The scanning optical system 105 forms an image as a latent image on the photoconductor 106 as an electrograph.
The latent image formed on the photoconductor 106 is developed as a toner image by adhering to the toner, and then transferred as a toner image to the sheet S via the intermediate transfer belt 107.
The toner image transferred onto the sheet S is fixed as an image by applying heat and pressure in the fixing portion 108, and is discharged by the paper ejection roller 109.

Other configurations such as the paper feed unit 103, the control unit 104, the scanning optical system 105, the photoconductor 106, the intermediate transfer belt 107, the fixing unit 108, and the paper ejection roller 109 are general image forming. It has a configuration as a device, and the description thereof will be omitted.

In the present embodiment, the image evaluation device 102 is arranged after the fixing portion 108 and before the paper ejection roller 109, and acquires spectral characteristics from a part of the image on the sheet S after fixing. It is an image evaluation device that feeds back to the control unit 104 to perform color management, and is a spectroscopic measurement device for acquiring the spectral characteristics of the image formed on the sheet S.

As shown in FIG. 2, the image evaluation device 102 includes a light source 11 attached so as to illuminate the sheet S, an imaging lens 20 as an imaging means for imaging the light emitted on the sheet S, and spectroscopy. It has a spectroscopic imaging module 30 which is a spectroscopic element for acquiring characteristics.
The image evaluation device 102 receives an On / Off timing of the light source 11 and a signal from a light receiving unit provided in the spectroscopic imaging module 30 described later, and is an image evaluation control unit for acquiring color information of an image and the like. Has 40.
The image evaluation control unit 40 may be mounted as a function of the control unit 104 provided in the image forming device 101, or may be independently provided in the image evaluation device 102.

The image evaluation device 102 has spectroscopic characteristics of a plurality of positions in the measurement region P which is at least a part of the image formed on the surface of the sheet S which is conveyed in the direction indicated by A in FIG. In other words, it has a function as a spectroscopic measuring device that measures color information.
The image evaluation device 102 irradiates the sheet S with light from the light source 11, forms an image with the imaging lens 20 using the light reflected on the surface of the sheet S as incident light, and disperses the light with the spectroscopic imaging module 30.

FIG. 3 shows a specific configuration of the spectroscopic imaging module 30. In FIG. 3, for the sake of simplification of the description, the incident direction of light is set to the Z direction, and among the directions perpendicular to the Z direction, the direction corresponding to the width direction of the sheet S corresponds to the Y direction and the conveying direction of the sheet S. Let the direction be the X direction.
The spectroscopic imaging module 30 is provided on the incident side, that is, on the −Z direction side, includes a plurality of regularly arranged openings 32, and is a pinhole array that is a region dividing portion that divides the incident light from the sheet S by the openings 32. It has a 31 and a diffraction grating 33 which is a spectroscopic unit that disperses light that has passed through an aperture 32, and a line sensor 34 which is a light receiving unit that receives light.
In this embodiment, for the sake of simplification of the explanation, only the case where the image evaluation device 102 has one spectroscopic imaging module 30 will be described, but a plurality of spectroscopic imaging modules 30 may be arranged side by side. Specifically, for example, if the line sensor 34 is a line sensor capable of measuring up to a width of 100 mm, the three line sensors 34 may be arranged side by side to form a spectroscopic measuring device capable of corresponding to a so-called A4 size.

The pinhole array 31 is an opening in which the openings 32 are regularly arranged at least in the Y direction. In the present embodiment, for example, the diameter of the openings 32 is φ = 20 μm, and the spacing (pitch) of the openings 32 is l = 300 μm. Is formed in.
By providing the pinhole array 31 in this way, each of the openings 32 provided in the pinhole array 31 acts like a diaphragm that limits the incident light of the independent image pickup apparatus, and depending on the measurement position. It functions as an area division part that divides the area.
That is, the pinhole array 31 has incident light from a plurality of measurement positions (P1, P2, P3 ... Shown in FIG. 2) in the measurement region P, as shown in FIG. 3 as a main ray diagram as a broken line. However, it functions as a region dividing portion in which the region is divided according to each measurement position by the passing opening 32.

The diffraction grid 33 is a diffractive optical element (DOE) in which fine grooves are formed in a predetermined direction, and as schematically shown in FIG. 4, the transmitted incident light is diffracted by diffracting the transmitted incident light. It is projected onto the line sensor 34 as first-order diffracted light dispersed for each wavelength. Although the diffraction grating 33 is a diffraction grating in the present embodiment, it is not limited to the diffraction grating as long as it is an optical element capable of irradiating the line sensor 34 with the dispersed light. ..

The line sensor 34 is a light receiving unit for receiving the primary diffracted light of the diffraction grating 33. In the present embodiment, in the line sensor 34, as the light receiving surface 35 is schematically shown in FIGS. 4A and 4B, the primary diffracted light is from the −X, −Y direction to the + X, + Y direction, in other words, XY. It is dispersed so as to extend diagonally with respect to a plane.
FIG. 4A is a diagram schematically expressing the spectrum of the primary diffracted light by changing the shaded shape of the projection of the primary diffracted light corresponding to one aperture 32 according to the wavelength.
FIG. 4B is a diagram schematically showing the projection of the primary diffracted light on the light receiving surface 35 and what kind of signal such projection is detected on the light receiving surface 35. For example, Y2 is shaded in the drawing. As shown, it shows how to detect as the sum of the predetermined measurement lines along the X direction.
With such a configuration, the primary diffracted light that is region-divided by the pinhole array 31 and dispersed by the diffraction grating 33 is irradiated onto the line sensor 34.
In order to reduce noise, it is desirable that the 0th-order diffracted light and the second-order or higher-order diffracted light other than the primary diffracted light do not reach the light receiving surface 35 or are not imaged on the light receiving surface 35. Since the specific configuration that exerts such an effect is not directly related to the characteristic form of the present invention, the description thereof will be omitted.

The line sensor 34 generates a signal according to the intensity of the irradiated primary diffracted light and transmits it to the image evaluation control unit 40.
In this embodiment, the light receiving surface 35 is partitioned at predetermined intervals as shown in FIG. 4B, and has a pixel structure for detecting the intensity of the first diffracted light received at each coordinate position. Have. Specifically, the light receiving surface 35 detects the sum of the same rows along the X direction as the intensity of the primary diffracted light at each position of Y1, Y2, and Y3. Since the primary diffracted light is incident on the light receiving surface 35 in a state of being separated by wavelength, it is detected as incident light at any position in the region extending obliquely with respect to the XY plane according to the wavelength. It will be. That is, the color information at the measurement position on the sheet S can be known depending on which position of the light receiving surface 35 among Y1, Y2, Y3 ...

That is, in the present embodiment, the spectroscopic imaging module 30 divides the light beam corresponding to the measurement position on the sheet S into regions by the pinhole array 31, and disperses the color information of the image at the measurement position on the sheet S by the diffraction grating 33. Can be obtained by.

The image evaluation control unit 40 can correctly reproduce the color of the image formed on the sheet S by comparing the spectral characteristics of the sheet S to be measured acquired by the line sensor 34 with a predetermined reference value. Determine if it is.
It should be noted that such a determination may be made, for example, as to whether or not the images on the plurality of sheets S are the same, or a predetermined evaluation pattern on the surface of the sheets S such as a color chart. May be formed and the pattern for such evaluation is judged.
Further, by using the line sensor 34, the spectral characteristics can be obtained at the same time at a plurality of measurement positions in the direction orthogonal to the transport direction of the sheet S, in other words, in the width direction of the sheet S, so that a conventional single spectroscope or the like can be used. It can be faster than the image evaluation method using.

Based on the determination result obtained by the image evaluation control unit 40, the control unit 104 calibrates the color information of the image formed on the sheet S by the image forming apparatus 101. With such a configuration, the image forming apparatus 101 can improve the color reproducibility by using the image evaluation apparatus 102.
In the present embodiment, the image evaluation device 102 is located in the middle of the transport path 110, after the fixing portion 108, and before the paper ejection roller 109, and the sheet S is arranged in the transport path 110. The upper part is transferred by a member such as a roller.
However, any configuration may be used as long as the image evaluation device 102 can be operated relative to the sheet S, and the sheet S may be transferred or the image evaluation device 102 may be operated.

By the way, when simultaneously measuring a plurality of measurement positions using the spectroscopic imaging module 30 as described above, it is desirable that the incident lights from different measurement positions are arranged so as not to interfere with each other.
Here, FIG. 12 shows, as a comparative example, a spectroscopic apparatus 200 for simultaneously measuring a plurality of points using a pinhole array in which a plurality of openings 32'are regularly arranged.
Similar to the present embodiment, the spectroscopic apparatus 200 includes a light source 11 attached so as to illuminate the sheet S, and an imaging lens 20 as an imaging means for imaging the light irradiated on the sheet S. doing.
The spectroscopic device 200 also has a spectroscopic imaging module 30'.

As shown in FIG. 13, the spectroscopic imaging module 30'has a pinhole array 31'with an opening 32', a line sensor 34'which is a light receiving portion, a diffraction grating 33' which is a diffraction means, and a diffraction grating 33'. It has a microlens array 39'provided between the pinhole array 31'and the pinhole array 31'.
The microlens array 39'is a lens array in which a plurality of lenses 39a are regularly arranged according to the position of the aperture 32'.
The luminous flux that has passed through the opening 32'is collected by the lens 39a and received as a signal by the line sensor 34'.

In the configuration using the microlens array 39', the light flux passing through the aperture 32'is collected by the lens 39a, so that the spread of the light flux in the aperture 32' can be ignored. Therefore, the position of the image plane of the imaging lens 20 is usually arranged near the aperture 32'so that the vicinity of the aperture 32'plays the role of a so-called diaphragm.
However, although the light utilization efficiency of the spectroscopic imaging module 30'is improved by using such a microlens array 39', there arises a problem that the spectroscopic imaging module 30'itself becomes expensive. On the other hand, if the microlens is simply not used, the efficiency of light utilization will be lowered, and there is a concern that the accuracy will be lowered.

In order to solve this problem, the present invention sets the incident angle of the incident light incident on the opening 32: θ, the diameter of the opening 32 of the pinhole array 31: φ, and the pitch of the opening 32 of the pinhole array 31: l. When the distance between the array 31 and the line sensor 34: d ₁ , the equation (1) is satisfied.

The derivation of the mathematical formula (1) will be described.
Among the light rays passing through the aperture 32 among the light fluxes from the imaging lens 20, the light rays incident at the maximum incident angle θ are shown by a dashed line in FIG.
Although it is expressed discretely in FIG. 6 for the sake of explanation, in reality, light rays are continuously incident at a plurality of incident angles with the maximum incident angle θ.
As shown in FIG. 6, by satisfying the mathematical formula (1), different incident lights incident on the adjacent openings 32 at the maximum incident angle θ do not overlap with each other at the same place of the line sensor 34. ..
Therefore, by satisfying the mathematical formula (1), it is possible to prevent the incident light from being repeatedly irradiated to the same place in the line sensor 34, and to accurately spectroscopically measure the light at a plurality of measurement positions at the same time. it can.
In other words, there is always an interval represented by the gap α (≧ 0) between the spectroscopic images formed by the adjacent openings 32.

Further, in the present embodiment, the position z of the image plane of the imaging lens 20 is any position between the pinhole array 31 and the line sensor 34, in other words, a predetermined position in the spectroscopic imaging module 30. It is adjusted so that.
With this configuration, the focal point of the incident light is located between the pinhole array 31 and the line sensor 34 as shown in FIG. 6, so that the spread of the primary diffracted light of the diffraction grating 33 is the opening 32 as in the comparative example. It is suppressed for the configuration in which the focusing point is located.
Further, in such a configuration, the mathematical formula (2) is satisfied when the position z of the image plane of the imaging lens 20 is set and the distance from the position z of the image plane to the light receiving surface 35: d ₂ .

According to this configuration, since the primary diffracted light is not detected in duplicate on the light receiving surface 35, it is possible to acquire the spectral characteristics at a plurality of locations with high accuracy while further reducing the size of the spectroscopic imaging module 30 of the image evaluation device 102. ..
Needless to say, d ₁ > d ₂ and the position z of the image plane of the imaging lens 20 is closer to the light receiving surface 35 than the opening 32 of the pinhole array 31.
Therefore, the spectral characteristics of a plurality of points can be measured at the same time while keeping the pitch of the opening 32: l smaller.

As one of the modifications of the present invention, the second embodiment will be described with reference to FIG.
In each of the embodiments described below, parts having the same configuration as that of the first embodiment are designated by the same reference numerals and the description thereof will be omitted as appropriate.
As shown in FIG. 6, the spectroscopic imaging module 30 in the second embodiment has a pinhole array 31, a diffraction grating 33, and a line sensor 34, and is between the line sensor 34 and the pinhole array 31. It is configured as an integral structure in which the voids of the above are filled with an optical material 50 such as glass.
The optical material 50 may be any generally used optical material such as optical glass or resin.

According to such a configuration, it is possible to reduce the influence of the optical material 50 fluctuating the positional relationship between the pinhole array 31 and the line sensor 34 due to vibration or the like.

Further, as another modification, the third embodiment will be described with reference to FIGS. 8 and 9.
As shown in FIG. 8, the spectroscopic imaging module 30 in the third embodiment has a pinhole array 31, a diffraction grating 33, and a line sensor 34, and is between the pinhole array 31 and the diffraction grating 33. It has a cylindrical lens 37 which is arranged in the above and has a refractive power (power) only in the X direction.
As shown in FIGS. 9A and 9B, the primary diffracted light projected on the light receiving surface 35 does not have power in the alignment direction of the line sensor 34, so that the cylindrical lens 37 has no power. When integrating in each region of Y2, Y3, ..., The luminous flux can be focused in the X direction without changing the resolution in the Y direction in which the cylindrical lens 37 has no power. In other words, the projection of the primary diffracted light in the first embodiment as shown in FIG. 9A is the projection of the primary diffracted light in the third embodiment as shown in FIG. 9B. , The length Lx in the X direction can be shortened without changing the length Ly in the Y direction.
With this configuration, the spectroscopic image of the primary diffracted light becomes sharp, so that it becomes easy to obtain a light intensity sufficiently higher than the minimum light receiving sensitivity of the line sensor 34, and it becomes easy to suppress disturbance detection other than the primary diffracted light. The N ratio is improved.

Further, as another modification, the fourth embodiment will be described with reference to FIG.
As shown in FIG. 10, the spectroscopic imaging module 30 in the fourth embodiment has a pinhole array 31, a diffraction grating 33, and a line sensor 34, and is between the pinhole array 31 and the diffraction grating 33. It has a lenticular lens 38, which is arranged in and has a refractive power (power) only in the Y direction.

As shown in FIG. 10, the lenticular lens 38 has a shape in which a plurality of semi-cylindrical lenses are arranged in the Y direction.
By refracting the incident light in the Y direction with such a configuration, as shown in FIG. 11B, the line sensor 34 is primary in the Y direction with respect to the projection in the first embodiment shown in FIG. 11A. Since the projection of the diffracted light can be compressed, the pitch l of the opening 32 can be made smaller.

The spectroscopic imaging module 30 in the present invention has a plurality of regularly arranged openings 32, and separates the pinhole array 31 that divides the light incident from the sheet S into regions by the openings 32 and the light that has passed through the openings 32. It has a diffraction grating 33 and a line sensor 34 that receives the light dispersed by the diffraction grating 33.
Further, the incident angle of the incident light incident on the opening 32: θ, the diameter of the opening 32 of the pinhole array 31: φ, and the pitch of the opening 32 of the pinhole array 31: l, and the pinhole array 31 and the line sensor 34 Distance between: When d ₁ , the mathematical formula (1) is satisfied.
2 ・ d ₁・ tan θ + φ ≦ l… (1)
With such a configuration, it is possible to measure the spectral characteristics of a plurality of points at the same time while reducing the cost.

Further, the spectroscopic imaging module 30 according to the second embodiment of the present invention is integrated by filling the gap between the pinhole array 31 and the line sensor 34 with the optical material 50.
With such a configuration, the influence of vibration can be suppressed and a stable light receiving image can be obtained.

Further, in the spectroscopic imaging module 30 according to the third embodiment of the present invention, the cylindrical lens 37 is arranged between the pinhole array 31 and the diffraction grating 33.
With such a configuration, the spread of the primary diffracted light in the X direction is suppressed, and it becomes easy to secure a light intensity higher than the minimum sensitivity of the line sensor 34, so that the S / N ratio can be improved.

Further, in the spectroscopic imaging module 30 according to the fourth embodiment of the present invention, the lenticular lens 38 is arranged between the pinhole array 31 and the diffraction grating 33.
With such a configuration, the projection of the primary diffracted light in the Y direction of the line sensor 34 can be compressed, so that the pitch l of the opening 32 can be further reduced.

Further, in the present embodiment, the image evaluation device 102 is arranged on the spectroscopic imaging module 30 and the incident light side of the spectroscopic imaging module 30, and is an imaging optical system for imaging the light incident on the spectroscopic imaging module 30. It has a barrel imaging lens 20 and.
The image plane of the imaging lens 20 is located between the aperture 32 of the pinhole array 31 and the light receiving surface 35 of the line sensor 34.
According to this configuration, the incident angle θ of the incident light and the pitch l of the opening 32 can be made smaller than when the position of the image plane is designed in the opening 32 as in the conventional case, so that the mathematical formula (1) is satisfied. Such a spectroscopic imaging module 30 can obtain a sufficient resolution.

Further, in the present embodiment, the image evaluation device 102 has a transport path 110 as a moving means for moving the sheet S, and uses the spectroscopic imaging module 30 to measure the image formed on the sheet S as the spectral characteristics of the image. To evaluate.
According to such a configuration, the spectral characteristics of the entire surface of the sheet S can be acquired by relatively moving the sheet S and the image evaluation device 102.

Further, in the present embodiment, the image forming apparatus 101 has an image evaluation apparatus 102.
With such a configuration, an image is formed on the sheet S, and the image formed on the sheet S can be evaluated and calibrated by feedback control, so that the reproducibility of color information and the like of the image is improved.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and the present invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.

For example, in the present embodiment, only the usage mode in which the image evaluation device 102 is incorporated as a part of the image forming device 101 has been described, but the present invention is described as a single image evaluation device that evaluates an image on an arbitrary recording medium. May be applied.
Alternatively, it may be used as a spectroscopic measurement device for acquiring spectroscopic characteristics on a recording medium without the purpose of evaluating an image.
Further, in each of the above-described embodiments, an image forming apparatus for forming an image on the sheet S by an electrophotographic method has been described as an example, but the sheet S may be any recording medium capable of recording information on the surface, and is made of paper. , Coated paper, thick paper, OHP, plastic film, prepreg, copper foil and the like.

The effects described in the embodiments of the present invention merely list the most preferable effects arising from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not it.

30 Spectral element (spectral imaging module)
31 Area division (pinhole array)
32 Aperture 33 Spectroscopy (diffraction grating)
34 Light receiving part (line sensor)
35 Light receiving surface 37 Cylindrical lens 38 Lenticular lens 39'Microlens array 101 Image forming apparatus 102 Image evaluation apparatus (spectral measuring apparatus)
θ Light incident angle φ Aperture diameter l Distance between adjacent openings d1 Distance between region dividing part and light receiving part d2 Distance from image plane to light receiving part P1, P2, P3 Measurement position S sheet (recording medium)

Japanese Unexamined Patent Publication No. 2-100964

Claims (7)

A region division unit having a plurality of regularly arranged openings and dividing the light incident from the measurement target by the openings.
A spectroscopic unit that disperses the light that has passed through the aperture,
It has a light receiving unit that receives the light dispersed in the spectroscopic unit, and has a light receiving unit.
When the incident angle of the light incident on the aperture is θ, the diameter of the aperture is φ, the distance between the adjacent openings is l, and the distance between the region dividing portion and the light receiving portion is d ₁ .
2 ・ d ₁・ tan θ + φ ≦ l
A spectroscopic element characterized by satisfying. In the spectroscopic element according to claim 1,
A spectroscopic element characterized in that a gap between the region dividing portion and the light receiving portion is filled with an optical material and integrated. In the spectroscopic element according to claim 1 or 2.
A spectroscopic element characterized in that a cylindrical lens is arranged between the region dividing portion and the spectroscopic portion. In the spectroscopic element according to claim 1 or 2.
A spectroscopic element characterized in that a lenticular lens is arranged between the region dividing portion and the spectroscopic portion. The spectroscopic element according to any one of claims 1 to 4,
It has an imaging optical system, which is arranged on the region dividing portion side of the spectroscopic element and for forming an image of light incident on the spectroscopic element.
A spectroscopic measurement device characterized in that the image plane of the imaging optical system is located between the region dividing portion and the light receiving portion. The spectroscopic measuring device according to claim 5 and
It has a moving means for relatively moving the measurement target and the spectroscopic measuring device.
An image evaluation device characterized in that an image formed on a recording medium is used as a measurement target and the spectral characteristics of the image are evaluated using the spectroscopic measurement device. An image forming apparatus comprising the image evaluation apparatus according to claim 6.

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