Hair observation device

Abstract

To observe the inside state of a hair easily and elaborately.SOLUTION: A hair observation device 10 includes: an oscillation unit 20 for oscillating a laser beam with a wavelength of 900nm to 1300nm, both inclusive; a light collecting unit 30 for collecting the laser beam oscillated by the oscillation unit 20 to a hair S; a scanning unit for scanning the position of the laser beam collected by the light collection unit 30; a first detector 40 for detecting the laser beam that has passed through the hair S; and a second detector 41 for detecting the laser beam that has been reflected by the hair S.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hair observation device.

Background Art

[0002] Generally, as a method for observing the internal state of hair, a method using an electron microscope or an X-ray microscope is known. In the method using an electron microscope, preparations such as cutting and slicing of hair are required, and it is difficult to perform observation easily. Also, it is difficult to observe changes when the same hair is processed. In the method using an X-ray microscope, since the device for handling X-rays becomes large-scale, it is difficult to perform observation easily. Also, it is difficult to observe changes when the same hair is processed.

[0003] Regarding these methods, observation of the internal state of hair has been performed using infrared rays. Patent Document 1 describes a method for observing the internal state of hair by irradiating the hair with infrared rays and observing the reflected light. An infrared LED is used for the irradiation of infrared rays. Patent Document 2 describes a method for observing the internal state of hair by irradiating the hair with infrared rays and utilizing the phase difference when the infrared rays pass through the hair. An infrared LED is used for the irradiation of infrared rays.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The methods described in Patent Documents 1 and 2 use infrared LEDs for infrared irradiation. However, infrared LEDs are difficult to focus, which presents a challenge in observing the detailed internal state of hair. Furthermore, the methods in Patent Documents 1 and 2 use either reflected or transmitted light, and therefore do not necessarily allow for detailed observation of the internal state of hair. For this reason, there is a need for a method that can observe the internal state of hair in more detail.

[0006] This invention was made in view of these circumstances, and its purpose is to provide a hair observation device that allows for easy and detailed observation of the internal state of hair. [Means for solving the problem]

[0007] The hair observation device for solving the above problems comprises an oscillator that emits laser light with a wavelength of 900 nm to 1300 nm, a focusing unit that focuses the laser light emitted from the oscillator onto the hair, a scanning unit that scans the position of the laser light focused by the focusing unit, a first detection unit that detects the laser light that has passed through the hair, and a second detection unit that detects the laser light reflected by the hair.

[0008] The hair observation device described above preferably has an autofocus function that automatically adjusts the focus of the laser light focused by the light-collecting unit. The hair observation device described above preferably has an automatic tracking function that automatically tracks the position of the hair when the observation position of the hair is changed.

[0009] The hair observation device described above preferably has a depolarization image acquisition unit that acquires a depolarization image using laser light that has passed through the hair. The hair observation device described above preferably has a confocal image acquisition unit that acquires a confocal image using laser light reflected by the hair. [Effects of the Invention]

[0010] According to the hair observation device of the present invention, the internal state of hair can be observed simply and in more detail.

Brief Description of Drawings

[0011] [Figure 1] It is a schematic diagram showing the configuration of the hair observation device. [Figure 2] It is a graph showing the relationship between wavelength and light scattering. [Figure 3] It is a graph showing the relationship between wavelength and biocompatibility. [Figure 4] It is a schematic diagram showing a specimen for observation. [Figure 5] It is a comparison of images with and without a pinhole. [Figure 6] It is a schematic diagram showing the configuration of the autofocus function unit. [Figure 7] It is a graph showing the relationship between the position of the Z stage and the focus value. [Figure 8] It is an image comparing the focus according to the position of the Z stage. [Figure 9] It is a schematic diagram showing the configuration of the automatic tracking function unit. [Figure 10] It is a schematic diagram showing the operation of the automatic tracking function unit. [Figure 11] It is a schematic diagram showing the mechanism of the automatic tracking function unit. [Figure 12] It is a transmission image of an example and a comparative example. [Figure 13] It is a graph showing the intensity distribution of the transmitted laser light of an example and a comparative example. [Figure 14] It is a transmission image, a reflection image, and a depolarized image of an example.

Modes for Carrying Out the Invention

[0012] An embodiment in which the hair observation device of the present invention is embodied will be described. As shown in FIG. 1, the hair observation device 10 has an oscillation unit 20 that oscillates laser light with a wavelength of 900 nm or more and 1300 nm or less. The hair observation device 10 also has a condensing unit 30 that condenses the laser light oscillated from the oscillation unit 20 onto a hair S that is an observation target, and a scanning unit that scans the position of the laser light condensed by the condensing unit 30. As will be described later, the scanning unit is also referred to as an image acquisition device 35. The hair observation device 10 further has a first detection unit 40 that detects the laser light transmitted through the hair S and a second detection unit 41 that detects the laser light reflected by the hair S among the laser light condensed by the condensing unit 30.

[0013] As shown in FIG. 1, a plurality of lenses 11 and mirrors 12 are arranged in the hair observation device 10, and an optical path P is formed by these plurality of lenses 11 and mirrors 12. The laser light oscillated from the oscillation unit 20 passes through the scanning unit along the optical path P and reaches the condensing unit 30. The laser light transmitted through the hair S reaches the first detection unit 40 along the optical path P. The laser light reflected by the hair S travels in the reverse direction of the optical path P from the oscillation unit 20, is reflected by a beam splitter 13, and reaches the second detection unit 41. Further, a collimator 14 and a half-wave plate 15 are arranged in the optical path P.

[0014] Hereinafter, the direction from the oscillation unit 20 toward the hair S is taken as the front in the front-rear direction, and the reverse is taken as the rear in the front-rear direction. The front-rear direction does not necessarily have to extend linearly and may be bent along the optical path P.

[0015] The components of the hair observation device 10 will be described. <Regarding the oscillation unit 20> The oscillation unit 20 is a light source that oscillates laser light with a wavelength of 900 nm or more and 1300 nm or less. The laser light with a wavelength of 900 nm or more and 1300 nm or less is not particularly limited, and for example, a YAG laser, a Nd:YAG laser, etc. can be used.

[0016] The wavelength of the laser light emitted from the oscillation unit 20 is not particularly limited, but is preferably 1000 nm to 1200 nm, and more preferably 1050 nm to 1100 nm.

[0017] Figure 2 shows the relationship between the wavelength of light and light scattering. The horizontal axis represents wavelength, and the vertical axis represents the rate of light scattering. As shown in Figure 2, the shorter the wavelength, the more likely light scattering is to occur. Figure 3 shows the relationship between light wavelength and bioabsorption. The horizontal axis represents wavelength, and the vertical axis represents bioabsorption. As shown in Figure 3, when the wavelength exceeds 1300 nm, bioabsorption tends to increase, or in other words, biopermeability tends to decrease.

[0018] As shown in Figures 2 and 3, when the wavelength of the laser light is between 900 nm and 1300 nm, light scattering is suitably suppressed, and biocommunication is improved. Figures 2 and 3 were created with reference to Chunyan Li and Qiangbin Wang, ACS Nano 2018, 9654-9659 (2018).

[0019] <About the light-gathering section 30> The light-gathering unit 30 is composed of a known objective lens. As shown in Figure 1, the objective lens has a first objective lens 31 located behind the hair S and a second objective lens 32 located in front of the hair S. The first objective lens 31 and the second objective lens 32 are positioned facing each other with the hair S being observed in between.

[0020] The laser light emitted from the oscillator 20 is focused through the first objective lens 31. By focusing through the first objective lens 31, a microbeam can be formed. The laser light that has passed through the hair S is collected by the second objective lens 32 and reaches the first detection unit 40.

[0021] The first objective lens 31 can be referred to as a focusing objective lens. The second objective lens 32 can be referred to as a collecting objective lens. <Regarding the first detection unit 40> The first detection unit 40 is composed of a known photodetector. Examples of photodetectors include an InGaAs photodetector, which is a near-infrared photodetector. The photodetector outputs an electrical signal based on the light intensity of the detected laser light.

[0022] <Regarding the second detection unit 41> The second detection unit 41 is composed of a known photodetector. An example of a photodetector is an InGaAs photodetector, which is a near-infrared photodetector. The photodetector outputs an electrical signal based on the light intensity of the detected laser light.

[0023] As shown in Figure 1, the second detection unit 41 is positioned behind the XY scanner, which will be described later. The laser light, reflected by the hair S and traveling backward along the optical path P, is reflected by the beam splitter 13 on the optical path P and reaches the second detection unit 41.

[0024] <About the scanning unit> The scanning unit is composed of a known XY scanner. An example of an XY scanner is a galvanometer scanner. The XY scanner scans the position of the focal point formed by the light-gathering unit 30 on the XY plane. By scanning the position of the focal point on the XY plane, two-dimensional images of the transmitted and reflected images of the hair S can be obtained. Specifically, the spatial distribution of light intensity detected by the first detection unit 40 and the second detection unit 41 is acquired as a digital image. Therefore, the scanning unit also functions as an image acquisition device 35.

[0025] <Regarding other components> As shown in Figure 1, the hair observation device 10 also includes a mounting section (not shown) for placing the hair S to be observed. It also includes a depolarization image acquisition unit 50 that acquires a depolarization image using laser light transmitted through the hair S, and a confocal image acquisition unit 55 that acquires a confocal image using laser light reflected by the hair S.

[0026] Furthermore, it has an autofocus function unit 60 (see Figure 6) which is an autofocus device that automatically adjusts the focus of the laser light concentrated by the light-gathering unit 30. It also has an autotracking function unit 70 (see Figure 9) which is an autotracking device that automatically tracks the position of the hair S when the observation position of the hair S is changed.

[0027] Other components will be described below. <Regarding the mounting section> The mounting section consists of a stage on which the hair S to be observed is placed, and a drive mechanism for moving the stage to a predetermined position. The drive mechanism allows the stage to be moved to a predetermined position in both the horizontal and vertical directions. The stage also has an opening along its thickness to allow laser light to pass through.

[0028] There are no particular restrictions on the method for placing the hair S for observation onto the stage, and known methods can be used as appropriate. As shown in Figure 4, for example, a hair S to be observed is placed on a glass slide 45. Double-sided tape 46 is attached to the glass slide 45 as a spacer. A cover slip 47 is then placed on top of the tape to sandwich the hair S. A liquid with a refractive index close to that of the hair S, glass slide 45, and cover slip 47 is filled between the glass slide 45 and the cover slip 47. The liquid with a refractive index close to that of the hair S, glass slide 45, and cover slip 47 is not particularly limited, but liquid paraffin can be used as an example. Filling with liquid paraffin can improve the contrast of the image. A specimen 48 for observation is prepared by the above method.

[0029] Next, the observation specimen 48 is placed on the stage so that the hair S overlaps the opening of the stage. This ensures that when laser light is shone through the opening of the stage, the laser light penetrates the observation specimen 48.

[0030] <About the polarization-free image acquisition unit 50> As shown in Figure 1, the depolarization image acquisition unit 50 is composed of polarizing elements. The polarizing elements consist of a pair: a first polarizing element 51 installed immediately after the first objective lens 31, and a second polarizing element 52 installed immediately before the second objective lens 32. The combination of the first polarizing element 51 and the second polarizing element 52 is not particularly limited, but for example, a left-handed circular polarizer can be used for the first polarizing element 51 and a right-handed circular polarizer for the second polarizing element 52. The first polarizing element 51 and the second polarizing element 52 are installed facing each other so that background light does not pass through. The transmitted light that has passed through the first polarizing element 51 and the second polarizing element 52 is detected by the first detection unit 40, thereby enabling the acquisition of a depolarization image.

[0031] By having a polarization-depolarized image acquisition unit 50, even if polarization occurs depending on the orientation of the hair axis, for example, a polarization-depolarized image that is independent of the orientation of the hair axis can be acquired. Furthermore, the first polarizing element 51 and the second polarizing element 52 are configured not to be placed on the optical path P when a depolarized image is not being acquired. In other words, they are configured to be placed on the optical path P as needed to acquire a depolarized image.

[0032] <About the confocal image acquisition unit 55> As shown in Figure 1, the confocal image acquisition unit 55 consists of a pinhole 56 and a convex lens 57. The pinhole 56 and the convex lens 57 are installed between the beam splitter 13 and the second detection unit 41 on the optical path P. The position of the pinhole 56 coincides with the focal position of the convex lens 57. This makes it possible to produce a confocal effect.

[0033] As shown in Figure 5, if there is no pinhole 56, the image will be accumulated in the depth direction of the hair S. Therefore, the image will be unclear. In contrast, the presence of a pinhole 56 allows for the acquisition of clearer images in specific cross-sections due to the confocal effect. This makes it possible to understand the internal state in more detail.

[0034] <About the autofocus function unit 60> As shown in Figure 6, the autofocus function unit 60 has a Z-stage 61 that moves the stage on which the specimen 48 for observation is placed to any position in the focal axis direction of the first objective lens 31. It also has a conversion device 62 that converts the image acquired by the image acquisition device 35 into numerical values, and an evaluation device 63 that evaluates the focus value as a numerical value converted by the conversion device 62.

[0035] The autofocus unit 60 changes the position of the Z-stage 61 in a stepwise manner, and the image acquired at each position is converted into a focus value by the conversion device 62 and recorded. The evaluation device 63 determines the position of the Z-stage 61 that yields the highest focus value and moves the Z-stage 61 to that position. By performing this series of operations automatically, it becomes possible to automatically focus on the specimen 48 for observation.

[0036] The method for converting an image to a focus value in the conversion device 62 is not particularly limited. For example, a method for calculating the Brenner gradient, a method for calculating frequency-domain entropy (hereinafter also referred to as FDE), or a method for calculating the luminance variance of the image (hereinafter also referred to as Variance) can be employed. Among these, it is preferable to use a method for calculating the Brenner gradient.

[0037] Figure 7 shows the relationship between the position of the Z-stage 61 and the focus value in each of the above methods for converting an image to a focus value. Figure 8 shows the relationship between the position of the Z-stage 61 and the focus value in the method for calculating the Brenner gradient. Figures 1 to 3 in Figure 8 represent the images at positions 1 to 3 of the Z-stage 61 in Figure 7.

[0038] As shown in Figure 7, the method for calculating the Brenner gradient shows a greater variation in the focus value with respect to changes in the position of the Z-stage 61 compared to the methods for calculating the FDE or variance. Therefore, as shown in Figure 8, it becomes easier to determine the position of the Z-stage 61 that yields the highest focus value. In other words, it becomes easier to focus on the specimen 48 for observation.

[0039] The conversion device 62 and evaluation device 63 of the autofocus function unit 60 may be built into a computer. That is, the hair observation device 10 may include a computer as a component and be configured to automatically focus using the conversion device 62 and evaluation device 63 within the computer.

[0040] <About the automatic tracking function unit 70> As shown in Figure 9, the automatic tracking function unit 70 includes a hair axis analysis device 71 that analyzes the axial center position of the hair S (hereinafter also referred to as the hair axis) from the image of the hair S acquired by the image acquisition device 35, and a position determination device 72 that determines the position of the image when acquiring the next image from the hair axis analyzed by the hair axis analysis device 71.

[0041] In Figure 10, the lines curving horizontally represent a single hair S. Also, one of the multiple rectangles arranged horizontally represents the area of ​​the image 73 obtained at once. As shown in Figure 10, since the hair S is curved and extends, when acquiring multiple images 73 by changing the observation position, there is a risk that the hair S may extend beyond the image 73 if the region of image 73 is moved linearly.

[0042] As shown in Figure 11, the hair axis analysis device 71 binarizes the image 73 of the hair S to create a binarized image 73a. The hair axis is displayed as a thin line 74 using the binarized image 73a. Next, the position determination device 72 determines the position for acquiring the next image 73 so that the hair axis is in the center position. The position of the stage is adjusted based on the determination of the position determination device 72.

[0043] By automating this series of operations, when changing the observation position of the hair and acquiring image 73, it is possible to prevent the hair S from extending beyond image 73. The hair axis analyzer 71 and position determination device 72 of the automatic tracking function unit 70 may also be built into the computer. That is, the hair observation device 10 may include a computer as a component and be configured to automatically track the position of the hair S using the hair axis analyzer 71 and position determination device 72 within the computer.

[0044] The hair observation device 10 of the present invention can be replaced with other terms such as a near-infrared microscope. The operation and effects of this embodiment will now be described.

[0045] (1) By having a wavelength of laser light emitted by the oscillation unit 20 that is between 900 nm and 1300 nm, light scattering can be suitably suppressed while maintaining good biopenetration. Furthermore, since the hair observation device 10 has a first detection unit 40 that detects laser light transmitted through the hair S and a second detection unit 41 that detects laser light reflected by the hair S, it becomes possible to observe the internal state of the hair S in more detail.

[0046] Furthermore, compared to methods using electron microscopes or X-ray microscopes, this method requires no prior preparation, making it easy to observe the internal state of hair S. It also allows for the observation of changes when the same hair S is treated.

[0047] (2) By having an autofocus function unit 60, it becomes possible to automatically focus on the hair S. (3) By having an automatic tracking function unit 70, when changing the observation position of the hair S and acquiring an image, the hair S can be prevented from going outside the image.

[0048] (4) By having a polarization-depolarized image acquisition unit 50, even if polarization occurs depending on the orientation of the hair axis, a polarization-depolarized image that is independent of the orientation of the hair axis can be obtained. (5) By having a confocal image acquisition unit 55, a clearer image can be acquired in a specific cross-section. Therefore, it becomes possible to grasp the internal state in more detail.

[0049] (6) Compared to methods using electron microscopes or X-ray microscopes, the equipment can be made smaller, making it easier to transport. Therefore, it becomes possible to perform measurements at the user's location without having to go to a facility equipped with specific equipment. In other words, it becomes possible to perform measurements on-site.

[0050] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically. In this embodiment, the mounting section consisted of a stage and a drive mechanism for moving the stage to a predetermined position, but it is not limited to this configuration. The mounting section may consist only of a stage, without a drive mechanism. By having the mounting section consist only of a stage, the hair observation device 10 can be made smaller.

[0051] In this embodiment, the hair S to be observed was placed on a glass slide 45 and sandwiched between cover glass 47, but the embodiment is not limited to this configuration. The hair may be directly attached to the stage.

[0052] In this embodiment, the autofocus function unit 60 and the autotracking function unit 70 were performed by adjusting the position of the stage, but the system is not limited to this configuration. Instead of adjusting the position of the stage, the position of the light-gathering unit 30 may be adjusted.

[0053] • The hair observation device 10 of this embodiment had an autofocus function unit 60, but the autofocus function unit 60 may be omitted. Similarly, the autotracking function unit 70 may also be omitted.

[0054] • In this embodiment, the hair observation device 10 had a confocal image acquisition unit 55, but the confocal image acquisition unit 55 may be omitted. • The hair observation device 10 of this embodiment had a polarization-depolarized image acquisition unit 50, but the polarization-depolarized image acquisition unit 50 may be omitted.

[0055] In this embodiment, the hair observation device 10 had a collimator 14 and a half-wave plate 15 arranged in the optical path P, but at least one of the collimator 14 and the half-wave plate 15 may be omitted. [Examples]

[0056] The following describes an embodiment that further elaborates on the above-described example. (Example 1) In the hair observation device 10 shown in Figure 1, a YAG laser with a wavelength of 1064 nm was used as the oscillator 20 to observe hair S.

[0057] (Comparative Example 1) In the hair observation device 10 shown in Figure 1, a laser with a wavelength of 488 nm was used as the oscillator 20 to observe the hair S.

[0058] (Comparative Example 2) In the hair observation device 10 shown in Figure 1, a laser with a wavelength of 785 nm was used as the oscillator 20 to observe the hair S. In Comparative Examples 1 and 2, a silicon photodetector was used.

[0059] Figure 12 shows the transmission images obtained in Example 1 and Comparative Examples 1 and 2. Figure 13 shows the intensity distribution of the transmitted laser light in each example. Note that the intensity distribution in Figure 13 refers to the intensity distribution along the dotted line L shown in Figure 12.

[0060] As shown in Figure 12, in Comparative Example 1, the entire image was dark, and almost no contrast was obtained within the hair S. In Comparative Example 2, although the image contrast was improved compared to Comparative Example 1, it was not possible to observe the inside of the hair S in detail. In contrast, in Example 1, the image contrast was good, and it was confirmed that the inside of the hair S could be observed in detail.

[0061] As shown in Figure 13, it was confirmed that the contrast in Example 1 was more than five times higher than that in Comparative Examples 1 and 2. Figure 14 shows the transmitted image, reflected image, and depolarized image obtained from three different samples, Samples 1 to 3, in Example 1. As shown in Figure 14, the transmitted image is generally bright, allowing for detailed observation of the internal state. In the reflected image, the dark areas in the transmitted image are brightened and emphasized, allowing for detailed observation of the internal state that was difficult to observe in the transmitted image. In the depolarized image, internal distortions of the hair S can be observed as differences in brightness. From the above, it can be concluded that in Example 1, the internal state of the hair S could be observed simply and in more detail. [Explanation of Symbols]

[0062] 10 Hair observation device 11 lenses 12 Mirror 13 Beam Splitter 14 Collimator 15 Half wave plate 20 Oscillator 30 Light-gathering section 31. First objective lens 32. Second objective lens 35 Image acquisition device 40 First detection unit 41 Second detection unit 45 microscope slides 46 Double-sided tape 47 Cover glass 48 specimen 50 Polarization-free image acquisition unit 51. First Modification Element 52 Second Polarizing Element 55 Confocal image acquisition section 56 pinholes 57 Convex lens 60 Auto focus function section 61 Z Stage 62 Conversion device 63 Evaluation device 70 Automatic tracking function unit 71 Hair axis analysis device 72 Positioning device 73 images 73a Binarized image 74 Thin line L dotted line P optical path S Hair

Claims

1. An oscillator that emits laser light with a wavelength of 900 nm or more and 1300 nm or less, A focusing unit that focuses the laser light emitted from the aforementioned oscillating unit onto the hair, A scanning unit scans the position of the laser beam focused by the aforementioned focusing unit on the XY plane, A first detection unit detects the laser light that has passed through the hair and outputs an electrical signal based on the light intensity of the detected laser light, It has a second detection unit that detects the laser light reflected by the hair and outputs an electrical signal based on the light intensity of the detected laser light, In the scanning unit, the spatial distribution of light intensity detected by the first detection unit and the second detection unit is acquired as a digital image. Furthermore, the hair observation device is characterized by having a depolarization image acquisition unit that acquires a depolarization image using laser light that has passed through the hair, and a confocal image acquisition unit that acquires a confocal image using laser light reflected by the hair.

2. The hair observation device according to claim 1, further comprising an autofocus function unit that automatically adjusts the focus of the laser light concentrated by the light-collecting unit.

3. The hair observation device according to claim 1 or 2, further comprising an automatic tracking function unit that automatically tracks the position of the hair when the observation position of the hair is changed.

Images