JPWO2019188264A1 - Light irradiation device - Google Patents

Abstract

The light irradiation device (100) is a light guide path that guides light from a plurality of light sources (101a, 101b) that emit light having different wavelengths and optical axes, and light from the plurality of light sources (101a, 101b) with a single-axis optical system. (102) is provided between the plurality of light sources (101a, 101b) and the light guide path (102), and the incident angle range of the light emitted from the plurality of light sources (101a, 101b) is expanded to expand the light guide path (102). It is provided with a lens (103) that is incident on one end of 102). Further, a light shield having a predetermined size on the optical axis of the light guide path (102) between the plurality of light sources (101a, 101b) and the lens (103) to prevent light from entering the light guide path (102). It may be provided with a part.

Description

The present invention relates to a light irradiation device that guides two light sources having different wavelengths and optical axes with a single-axis optical axis system.

By irradiating an object with two different light sources and dispersing the reflected light by wavelength, the state of the object can be detected by wavelength. A light irradiation detection device having such an optical system can be used, for example, for detecting caries teeth.

As a related technique, conventionally, for example, there is a technique of arranging a spherical lens between a light guide member (light guide) of an endoscope and a light source to make uneven brightness uniform (see, for example, Patent Document 1 below). ). Further, there is a technique for suppressing the difference between the center and the peripheral portion of the intensity distribution of the illumination light by a dimming mechanism for the light guide member (light guide) of the endoscope (see, for example, Patent Document 2 below). Further, there is a technique for obtaining a uniform intensity distribution by injecting a laser light source such as a projector with a condenser lens at an angle other than perpendicular to the incident end surface of the light guide means (see, for example, Patent Document 3 below). Further, there is a technique for suppressing a change in colored light in an optical fiber when a plurality of light sources having different wavelengths are mixed in the optical fiber (see, for example, Patent Document 4 below).

Japanese Unexamined Patent Publication No. 2003-126033 Japanese Unexamined Patent Publication No. 2015-195974 International Publication No. 2013/088466 Japanese Unexamined Patent Publication No. 2016-133737

However, the above-mentioned conventional technique cannot mix colors so as to reduce the light intensity pattern (color unevenness) of light sources having a plurality of wavelengths in a short light guide path. In the techniques of Patent Documents 1 to 3, the light source is monochromatic light and does not have a light source having a plurality of wavelengths. The technique of Patent Document 4 suppresses a change in emission color (color unevenness) in the optical axis direction while guiding an optical fiber, and cannot suppress color unevenness when the optical fiber is shortened.

The present invention provides a light irradiation device capable of suppressing color unevenness even if the length of the optical system is short by guiding light sources having a plurality of wavelengths with a uniaxial optical system in order to solve the above-mentioned problems caused by the prior art. The purpose is to do.

In order to solve the above-mentioned problems and achieve the object, the light irradiation device according to the present invention uses a plurality of light sources that emit light having different wavelengths and optical axes, and a single-axis optical system that emits light from the plurality of light sources. A light guide path for guiding light, a lens provided between the plurality of light sources and the light guide path, and a lens that expands the incident angle range of light emitted from the plurality of light sources and causes the light to enter one end of the light guide path. It is characterized by having.

Further, the light source is provided between the plurality of light sources and the lens, and has a light-shielding portion having a predetermined size on the optical axis of the light guide path and preventing the light from entering the light guide path. And.

Further, the lens is a spherical lens.

Further, the core diameter of the light guide path is the same as or smaller than the diameter of the spherical lens.

Further, the light-shielding portion is characterized by being an absorber or a reflector formed on the incident surface side of the lens.

Further, it is characterized in that light of a plurality of wavelengths incident from one end of the light guide path is irradiated to an object through the light guide path.

Further, light of a plurality of wavelengths incident from one end of the light guide path is irradiated to the object through the light guide path, and the surface state of the target object is detected based on the reflected light from the light guide path. It is characterized by.

Further, one of the plurality of light sources has a wavelength at which plaque fluoresces due to irradiation of the tooth as the object, and the other light source has a wavelength at which plaque does not fluoresce due to irradiation with the tooth. The light source is provided with a control circuit for detecting plaque based on the difference in light intensity of the reflected light when the one and the other light sources are driven in a time-divided manner.

According to the light irradiation device according to the present invention, a light source having a plurality of wavelengths is guided by a uniaxial optical system, and even if the length of the optical system is short, color unevenness can be suppressed.

FIG. 1 is a diagram showing a configuration example of the light irradiation device according to the first embodiment. FIG. 2 is a diagram showing light dispersion by the lens of the light irradiation device according to the first embodiment. FIG. 3 is a diagram showing a color distribution of a simulation result of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment. FIG. 4 is a diagram showing an analysis model of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment. FIG. 5 is a chart in which the analysis results of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment are quantified. FIG. 6 is a diagram showing a dispersed state of light of one wavelength among the two wavelength light sources. FIG. 7 is a diagram showing a configuration example of the light irradiation device according to the second embodiment. FIG. 8 is a chart in which the analysis results of light color unevenness due to the light-shielding portion of the light irradiation device according to the second embodiment are quantified. FIG. 9 is a chart showing the relationship between the size of the light-shielding portion of the light irradiation device according to the second embodiment and the color unevenness. FIG. 10 is a diagram showing another configuration example of the light irradiation device according to each embodiment. FIG. 11 is a chart illustrating a change in autofluorescence intensity depending on each position of the tooth. FIG. 12 is a diagram showing a configuration example of a plaque detection toothbrush. FIG. 13 is a diagram showing light dispersion by various lenses of the light irradiation device according to the third embodiment.

A preferred embodiment of the light irradiation device according to the present invention will be described in detail below with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration example of the light irradiation device according to the first embodiment. 1 (a) is a front view and FIG. 1 (b) is a side view. In FIG. 1, among the light irradiation detection devices 100, only the light irradiation device according to the main configuration of the first embodiment, that is, the light emitting structure portion is shown. The structure of the light detection portion of the light irradiation detection device 100 will be described later.

The light emitting structure portion 110 of the light irradiation detection device 100 includes light sources 1 and 2 (101) having different wavelengths, a light guide path 102, and a lens 103. The light source 1 (101a) and the light source 2 (101b) emit light having different wavelengths, and the light sources 1 and 2 (101a, 101b) are arranged close to each other, but have their respective optical axes. The center positions are separated by a predetermined distance (pitch) L. That is, the centers (optical axes) a and b of the light sources 1 and 2 (101a, 101b) each have an axis deviation of L / 2 with respect to the optical axis O of the light guide path 102.

In FIG. 1, the luminous flux emitted by the light sources 1 and 2 (101a, 101b) is parallel light, and the diameter W of the light guide path 102 (length in the vertical direction in the figure) W and the two light sources 1, 2 (101a, 101b). The diameters of the light sources W1 + W2 emitted by each of them are almost the same.

The light guide path 102 may be any member as long as it is a member that guides light, and for example, an optical fiber or a tubular reflector can be used. A lens 103 is provided between the light sources 1 and 2 (101a, 101b) and the light guide path 102. In the example of FIG. 1, the lens 103 is a spherical lens. The lens 103 expands the incident angle range of the lights A and B emitted from the light sources 1 and 2 (101a, 101b) and causes them to be incident on one end of the light guide path 102. The lens 103 is provided, for example, on the incident end surface of the optical fiber which is the light guide path 102, and disperses the angles of the light emitted from the light sources 1 and 2 (101a, 101b) according to the incident position in the light guide path 102. Propagate.

For example, the lens (spherical lens) 103 has a refractive index n = 1.51 and a diameter φ = 3.0 mm, and the light guide path 102 is made of acrylic resin and has a refractive index n = 1.49 and a core diameter φ (W). = 3.0 mm. As the light sources 1 and 2 (101a and 101b), surface emitting LEDs and LDs (Laser Diodes) are used, respectively. The light sources 1 and 2 (101a and 101b) each have a size of 1.5 mm × 3 mm, and the pitch L is 1.5 mm. For example, the wavelength of the light emitted by the light source 1 (101a) is 405 nm, and the wavelength of the light emitted by the light source 2 (101b) is 465 nm.

FIG. 2 is a diagram showing light dispersion by the lens of the light irradiation device according to the first embodiment. The lens 103 shown in FIG. 1 is a spherical lens, and the light dispersion by the spherical lens 103 will be described. FIG. 2 shows a dispersed state of light emitted from one of the light sources 1 (101a) arranged in the upper half of the optical axis O.

The luminous flux A of the parallel light incident on the spherical lens 103 changes the traveling direction in different angular directions depending on the position of the spherical lens 103 where it is incident and refracted. By providing the spherical lens 103 and expanding the incident angle range of the luminous flux A into the light guide path 102, light of two different wavelengths can be mixed and color unevenness can be eliminated.

The spherical lens 103 is not limited to being used for expanding the incident angle range. By using the lens 103, it is possible to expand the incident angle range, not limited to the spherical lens.

(Detection of mixed state of two wavelengths by optical simulation)
FIG. 3 is a diagram showing a color distribution of a simulation result of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment. Light of two wavelengths is incident on the light guide path (optical fiber) 102 by the light irradiation detection device 100 shown in FIG. 1, and light at each point in the light guide path 102 plane is analyzed by illumination analysis software. It shows the light intensity pattern (dispersed state).

The state without color unevenness means that the light patterns (intensity distributions) of the two wavelengths match in the light guide path 102 plane, and it is permissible to have the light intensity distribution in the plane. A state with color unevenness is a state in which the patterns of light of two wavelengths do not match, for example, each part in the plane has only the first wavelength in a certain part and only the second wavelength in another part. It is a state in which there is a difference in the light intensity distribution of wavelengths.

3 (a) and 3 (b) show the positions of the light guide path (optical fiber) 102 from the incident surface, respectively, and FIG. 3 (a) is 2 mm from the light guide path (optical fiber) 102 inlet (incident surface of the luminous flux A). (B) shows a light intensity pattern (dispersed state) in which each wavelength is combined at a position 14 mm from the incident surface.

These FIGS. 3 (a) and 3 (b) correspond to the structure of the light irradiation detection device 100 of the first embodiment, that is, the structure including the light guide path (optical fiber) 102 and the spherical lens 103, and the prior art. The light intensity pattern (distributed state) for the structure of only the optical fiber is shown.

According to the light irradiation detection device 100 of the first embodiment, the two colors are mixed at 2 mm in FIG. 3 (a), and the two colors are mixed at 14 mm in FIG. 3 (b) to eliminate the color unevenness. Is shown.

On the other hand, in the conventional structure of only an optical fiber without a spherical lens, the respective lights A and B are detected in FIGS. 3 (a) and 3 (b), indicating that the color unevenness is not eliminated. There is. As described above, according to the light irradiation detection device 100 of the first embodiment having the spherical lens 103, the distance is shorter than the structure of the prior art with respect to the optical axis (length) direction of the light guide path (optical fiber) 102. Color unevenness of light of wavelength can be eliminated.

Next, since the color distribution map shown in FIG. 3 is evaluated by the user who visually observes the image, the following digitization was attempted. Evaluation surfaces are installed at predetermined intervals in the optical axis (length) direction in the light guide path (optical fiber) 102, and each evaluation surface is divided by a predetermined size mesh (for example, 51 × 51) and incident on each mesh. The intensity of the light to be emitted was calculated for each wavelength. At this time, the difference in the intensity of light of two wavelengths was calculated for each mesh, the sum of all the meshes was taken, and the value divided by the total amount of light was taken as the degree of color unevenness.

Color unevenness = Σ (I light A-I light B [W]) / (I light A + I light B [W])

The smaller the degree of color unevenness, the smaller the difference (similar) in the light intensity patterns of the two wavelength light sources 1 and 2 (101a, 101b) in the light guide path 102 plane, and the smaller the color unevenness. ..

FIG. 4 is a diagram showing an analysis model of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment. In the analysis model 400 shown in FIG. 4, light is incident on the light guide path 1 (402) from the two wavelength light sources 1 and 2 (102a, 102b) via the spherical lens 1 (401). The spherical lens 2 (103) of the light irradiation detection device 100 and the light guide path 2 (light guide path 102) are arranged at the outlet (exit surface) of the light guide path 1 (402).

As for the structure corresponding to the prior art, a model is used in which the spherical lens 103 of FIG. 4 is removed and the light guide path 2 (light guide path 102) is brought close to the light guide path 1 (402).

FIG. 5 is a chart in which the analysis results of color unevenness of light having two wavelengths by the light irradiation device according to the first embodiment are quantified. The degree of color unevenness of light of two wavelengths based on the result of the analysis model shown in FIG. 4 is shown. The vertical axis represents the degree of color unevenness, and the horizontal axis represents the propagation distance of the light guide path 2 (light guide path 102).

As shown in FIG. 5, even in the structure of the prior art without the spherical lens 2 (103), the value of the color unevenness of the two wavelengths of light A and B becomes smaller as the propagation distance of the light guide path 102 becomes longer. (That is, color unevenness is reduced). However, in the range where the propagation distance is 30 mm or more, the value of the degree of color unevenness tends to increase (color unevenness occurs again).

On the other hand, in the structure having the spherical lens 2 (103) like the light irradiation detection device 100 of the first embodiment, the value of the degree of color unevenness is higher than that of the structure of the prior art over the entire propagation distance of the light guide path 102. It can be seen that the color unevenness is eliminated as compared with the conventional technique. In particular, the value of the degree of color unevenness sharply decreases in a range where the propagation distance is short, for example, in the range of 0 mm (optical inlet) to 14 mm, and the color unevenness is eliminated in a short distance for the light entering the light guide path 102. It is shown.

In the first embodiment described above, light from light sources 1 and 2 (101a, 101b) having different wavelengths is incident on the light guide path 102, which is a single light guide path. At this time, the centers (optical axes) a and b of the light sources 1 and 2 (101a, 101b) are displaced with respect to the optical axis O of the light guide path 102, but a lens 103 such as a spherical lens is located at the incident end of the light guide path 102. To place. As a result, the optical patterns of the light sources 1 and 2 (101a, 101b) having different wavelengths in the 102 planes of the light guide path (optical fiber) can be made similar in a short propagation distance, and color unevenness can be eliminated.

Conventionally, a structure that guides light into an optical fiber is known. When light is emitted from multiple locations and is parallel light of different wavelengths, the angles are preserved and propagated in the optical fiber, so there is no color mixing, or mixed colors and non-mixed areas alternate. Appears in. Further, when the light is not completely parallel light, the color unevenness is reduced as the light propagates over the optical fiber for a long distance.

Here, the material of the optical fiber includes plastic, quartz, and the like, but quartz is expensive and difficult to use for general consumer products and consumables. However, when low-cost plastic is used, autofluorescence occurs depending on the wavelength of light used. For example, in a fluorescence measuring instrument, the fluorescence from an object often has a weak light intensity with respect to the irradiation light, so even if plastic is used, a small amount, that is, the length (propagation distance) of the optical fiber is kept short. I have a request.

In this regard, in the prior art, unless a sufficient propagation distance (length of optical fiber) is secured, light from a plurality of light sources having different optical axes forms a separated pattern and irradiates the same region of the object with the same light intensity. It causes problems that cannot be caused. On the other hand, if an attempt is made to secure a sufficient length of the optical fiber, it becomes a rate-determining condition that hinders miniaturization.

On the other hand, according to the first embodiment, the light sources 1 and 2 (101a, 101b) having different wavelengths in the 102 planes of the light guide path (optical fiber) are dispersed by the refraction of the lens to disperse the light emission angle range. Since the light intensity pattern of the above can be made similar with a short propagation distance and color unevenness can be eliminated, the length (propagation distance) of the optical fiber can be kept short and the color unevenness can be eliminated even when plastic is used as the light guide path 102. it can. In addition, the use of plastic makes it possible to reduce the cost of the light irradiation device.

Further, in the first embodiment, the light irradiation detection device 100 is configured to irradiate an object with light having a different wavelength and detect the reflected light, but the present invention is not limited to this, and the object is irradiated with light having a different wavelength. It has the effect of suppressing color unevenness even if the configuration of the light irradiation device is as simple as possible.

(Embodiment 2)
In the second embodiment, the basic structure is the same as that of the light irradiation detection device 100 described in the first embodiment described above, and a configuration for reducing color unevenness with a shorter propagation distance will be described.

FIG. 6 is a diagram showing a dispersed state of light of one wavelength among the two wavelength light sources. In the configuration of the light irradiation detection device 100 of the first embodiment, the dispersed state of the light A emitted from one of the light sources 1 (101a) is shown.

The light that passes through the central portion of the spherical lens 103 and enters the light guide path (optical fiber) 102 travels in parallel with the light guide path (optical fiber) 102 because the angle change due to refraction is small. Therefore, a relatively long propagation distance is required for the first reflection to occur, and the light guide path 102 reaches the exit (emission end) with a relatively small number of reflections. In the example shown in FIG. 6, the light A passing through the central portion (near the optical axis O) of the spherical lens 103 is hard to be reflected, the light is biased (biased), and the light intensity of the lower half of the light guide path 102 is increased. It has been shown to be strong. Light that is not reflected or light that is reflected less frequently causes color unevenness.

In the second embodiment, the color unevenness is eliminated in a shorter transmission distance by removing the light passing through the central portion (near the optical axis O) of the optical fiber.

FIG. 7 is a diagram showing a configuration example of the light irradiation device according to the second embodiment. In the configuration shown in FIG. 7, the same components as those in the first embodiment are designated by the same reference numerals. In addition to each configuration of the incident structure portion 110 of the first embodiment, the incident structure portion 710 of the light irradiation detection device 100 of FIG. 7 shields light from the incident side of the spherical lens 103 on the optical axis O of the light guide path 102. The part 704 is arranged.

The light-shielding portion 704 is formed in a circular shape having a size of, for example, φ1.2 mm. The light-shielding portion 704 can be formed of an absorber that absorbs light directly on the incident side of the spherical lens 103. For example, the absorber can be formed by applying black ink to the spherical lens 103.

The light-shielding portion 704 may have a configuration that does not allow light of the formed size portion (φ1.2 mm) to pass to the light guide path 102 side, and has a reflector formed on the incident surface side on the optical axis O of the spherical lens 103. May be. As the reflector, for example, in the case of a metal film, it is desirable to arrange a black body or the like that absorbs the reflected light of the light-shielding portion 704 on the reflection side (around the light sources 1 and 2 and the like). In addition, as the reflector, a light scattering surface may be formed on the incident surface side on the optical axis O of the spherical lens 103. When the light-shielding portion 704 is a reflector of these metal films or a scattering surface, a black body or the like that absorbs the reflected light of the metal film or the scattering surface may be arranged on the light reflecting side (around the light sources 1 and 2). desirable.

Further, when the light sources 1 and 2 (101a and 101b) are configured to emit parallel light, the light shielding portion 704 is independently arranged at a position between the light sources 1 and 2 (101a and 101b) and the spherical lens 103. You may. For example, the light-shielding portion 704 may be formed on the exit surface of the light sources 1 and 2 (101a, 101b). Further, when the light sources 1 and 2 (101a, 101b) are LEDs, the light source is configured so that a part of the light emitting elements of the plurality of LEDs, that is, the light emitting element corresponding to the arrangement portion of the light shielding portion 704 is not provided. The 101 may have a function equivalent to the light-shielding portion 704.

FIG. 8 is a chart in which the analysis results of light color unevenness due to the light-shielding portion of the light irradiation device according to the second embodiment are quantified. Similar to the first embodiment, an analysis model is used to show the degree of color unevenness of light having two wavelengths. The vertical axis represents the degree of color unevenness, and the horizontal axis represents the propagation distance of the light guide path 102.

As shown in FIG. 8, it is shown that when the light-shielding portion 704 of the second embodiment is provided, the color unevenness is eliminated in a shorter distance than when the light-shielding portion 704 is not provided. In the example of FIG. 8, the value of the degree of color unevenness is the smallest in the portion where the propagation distance is 8 mm. Therefore, in the second embodiment, the color unevenness can be eliminated even if the length of the light guide path 102 is 8 mm or less (for example, about 5 mm to 8 mm).

FIG. 9 is a chart showing the relationship between the size of the light-shielding portion of the light irradiation device according to the second embodiment and the color unevenness. The color unevenness (color unevenness degree) for each different size of the light-shielding portion 704 is shown. The vertical axis represents the degree of color unevenness, and the horizontal axis represents the propagation distance of the light guide path 102. The characteristics of the light source 101, the light guide path 102, and the spherical lens 103 are the same as those in the first embodiment.

FIG. 9 shows the characteristics of the light-shielding portion 704 having a size of φ0.4 mm, φ1.0 mm, φ1.2 mm (Embodiment 2), and no light-shielding portion 704 (Embodiment 1). Of these sizes, as described in the second embodiment, when the light-shielding portion 704 has a diameter of 1.2 mm, the propagation distance is short and the value of the degree of color unevenness is the smallest (there is little color unevenness). For example, under the condition that the color unevenness value is 0.2 or less, the color unevenness value becomes the smallest when the size of the light-shielding portion 704 is φ1.2 mm and the transmission distance is the shortest. The value with the smallest degree of color unevenness at φ1.2 mm has a propagation distance of about 8.5 mm.

Next, when viewed at a short propagation distance, the characteristic of φ1.0 mm reduces the value of the degree of color unevenness. Next, φ0.4, and finally, there was no light-shielding part 704. If there is no light-shielding portion 704, that is, if the light-shielding portion 704 is not provided, and the color unevenness value is 0.2, the value will be around 0.2. It cannot be done and requires a longer propagation distance. According to FIG. 9, the smaller the size of the light-shielding portion 704 is, the longer the propagation distance is required with respect to the magnitude of the luminous flux of the light A and B emitted by the light sources 1 and 2 (101a and 101b), and the light guide path 102 is shortened. If this is the case, it has been shown that color unevenness occurs.

FIG. 10 is a diagram showing another configuration example of the light irradiation detection device according to each embodiment. 10 (a) and 10 (b) show a configuration example using a light source such as an LED that emits diffused light as the light source 101.

As shown in FIG. 10A, there are two collimating lenses whose centers are located on the optical axes a and b between the light sources 1 and 2 (101a and 101b) that emit diffused light and the spherical lens 103. 1101 (1101a, 1101b) is arranged. The collimating lens 1101 (1101a, 1101b) converts the diffused light emitted by the light sources 1 and 2 (101a, 101b) into parallel light and causes it to enter the spherical lens 103.

Further, in the example shown in FIG. 10B, one spherical lens whose center is located on the optical axis O between the light sources 1 and 2 (101a, 101b) that emit diffused light and the spherical lens 103. 1102 is placed. The spherical lens 1102 converts the diffused light emitted by the light sources 1 and 2 (101a, 101b) into substantially parallel light and causes it to enter the spherical lens 103. Here, the luminous flux of the light A of one light source 1 (101a) is emitted to the upper half of the spherical lens 103 (not emitted to the lower half of the light shielding portion 704), and the light flux of the other light source 2 (101b) is emitted. The luminous flux of the light B is set to the distance between the light sources 1 and 2 (101a, 101b) and the spherical lens 1102 so that the light flux is emitted to the lower half of the spherical lens 103 (not emitted to the upper half of the light shielding portion 704). adjust.

As shown in FIG. 10, the light emitted by the light sources 1 and 2 (101a, 101b) is not limited to parallel light and may be diffused light, and diffused light such as an LED may be used in addition to LD. Then, the light incident on the spherical lens 103 provided at the entrance (incident end) of the light guide path 102 may be made into parallel light by using the collimating lens 1101 (1101a, 1101b).

In the above description, it has been described that in each embodiment, the light intensity patterns in the light guide paths 102 planes of the light A and B having different wavelengths are approximated to suppress the color unevenness. Focusing mainly on the matching of light intensity patterns, the two light sources 101 (101a, 101b) emit light at the same time.

Here, according to the structures of the incident structure portions 110 and 710 of light of each embodiment, the distribution state of light in the light guide path 102 when only one light source 101a is driven to emit light, and the other light source 101b. The light distribution state in the light guide path 102 when only the light source is driven to emit light can be made substantially the same.

That is, even when either one of the light sources 101 is made to emit light, the light of the light distribution pattern approximated from the two light sources 101 can be emitted from the outlet (exit end) of the light guide path 102. Therefore, according to each of the above embodiments, not only when the light sources 101 (101a, 101b) having different wavelengths are simultaneously emitted, but also the light source 101a or the light source 101b having one of the wavelengths is emitted and driven one by one. Even in this case, the irradiated portion of the object can be surface-irradiated without any difference in the light intensity pattern of each wavelength and the irradiation state is not biased.

(Application example of light irradiation detection device)
Next, a plaque detection toothbrush will be described as an application example of the light irradiation detection device according to each of the above-described embodiments. The light irradiation detection device 100 shown in FIGS. 1 and 7 can be applied to, for example, a plaque detection toothbrush. Here, the above-mentioned object is a tooth, and irradiates the tooth with light A and B having different wavelengths.

Then, as the light sources having different wavelengths, the wavelength of the light A of the light source 1 (101a) is 405 nm, the wavelength of the light B of the light source 2 (101b) is 465 nm, and the light source 1 (101a) and the light source 2 (101b) are driven by time division. Then, at a certain time, only one of them is driven to emit light.

Here, when the tooth is irradiated with light of light A having a wavelength of 405 nm, a substance forming the tooth (enamel, dentin collagen, etc.) is excited, and fluorescence is generated from the tooth. When plaque is attached to the tooth, irradiation with light A (wavelength 405 nm) causes fluorescence having a peak in the wavelength band of 635 nm from the plaque. On the other hand, in the light of light B (wavelength 465 nm), fluorescence emission due to dental plaque does not occur.

FIG. 11 is a chart illustrating a change in autofluorescence intensity depending on each position of the tooth. The wavelength at which fluorescence was detected is 635 nm. The vertical axis is the light intensity and the horizontal axis is the tooth position Z. When looking only at the fluorescence intensity when irradiated with one of the excitation lights, it can be seen that if the tooth positions are different, autofluorescence is performed with different intensities. When comparing the light intensities when excited by light A (wavelength 405 nm) and light B (wavelength 465 nm), the fluorescence intensities are almost equal at the same position (for example, 0 [mm]) (for example, in the figure). P). However, it can be seen that the fluorescence intensity changes when the position of the tooth is moved.

Therefore, in the plaque detection toothbrush, it is necessary to irradiate the same position with two lights A (wavelength 405 nm) and light B (wavelength 465 nm) having different wavelengths. In this regard, according to the incident structure portions 110 and 710 of light described above, since both the lights A and B can be made to have an approximate light intensity pattern, the same position of the teeth is irradiated with the same intensity of light. be able to.

Then, the teeth are irradiated with light A and B of different wavelengths, and the fluorescence ratio of the wavelength C (fluorescence) detected by the light detector 1205 at 635 nm (of the light A and B) according to the accumulated state of the dental plaque of the tooth. The accumulated state of plaque can be detected based on the difference in light intensity).

FIG. 12 is a diagram showing a configuration example of a plaque detection toothbrush. In FIG. 12, the plaque detection toothbrush 1200 is composed of a main body portion (handle) 1210 and a toothbrush portion 1220. The main body 1210 includes an exterior case 1211 that is gripped by the user's hand.

The outer case 1211 is provided with a switch 1211a that receives an operation by the user of the plaque detecting toothbrush 1200. The outer case 1211 is waterproofed to prevent water from entering the inside of the outer case 1211. Inside the outer case 1211, a power supply 1212, two light sources 101 (101a, 101b) having different wavelengths, a coaxial optical system 1214, a photodetector 1215, a control circuit 1216, a notification device 1217, and the like are provided. The power supply 1212 supplies electricity to each part of the plaque detecting toothbrush 1200. The power supply 1212 may be a primary battery or a secondary battery.

The lights A and B emitted by the light sources 101 (101a and 101b) are incident on the coaxial optical system 1214. The coaxial optical system 1214 corresponds to the incident structure portions 110 and 710 of the above light. The coaxial optical system 1214 guides the lights A and B emitted from the light sources 101 (101a, 101b) to the toothbrush portion 1220 side, and detects the fluorescence of teeth and plaque incident from the toothbrush portion 1220 side on the photodetector 1215 side. Lead to.

The photodetector 1215 detects the intensity of light near a specific wavelength contained in the fluorescence derived from the coaxial optical system 1214, and outputs a signal corresponding to the detected fluorescence intensity to the control circuit 1216. The control circuit 1216 can be realized by a microcomputer provided with a CPU, various memories, signal input / output terminals, and the like, and drives and controls each part included in the plaque detection toothbrush 1200.

The control circuit 1216 drives and controls each part of the plaque detection toothbrush 1200. The control circuit 1216 controls ON / OFF of the light source 101 (101a, 101b) according to the signal output from the operated switch 1211a, or plaque based on the signal output from the photodetector 1215. The amount is calculated and a notification signal (a signal for notifying the user of the amount of plaque) according to the amount of plaque is output to the notification device 1217. Further, the control circuit 1216 switches the light source 101a of wavelength A and the light source 101b of wavelength B in a time division manner to drive light emission.

The notification device 1217 can be realized by, for example, a light emitting element such as an LED. In this case, the amount of plaque is notified by turning on or blinking the LED in a pattern based on the notification signal output from the control circuit 1216. Alternatively, the notification device 1217 may be realized by, for example, an eccentric motor instead of the LED. In this case, the amount of plaque can be notified by vibration by rotating the eccentric motor in a pattern based on the notification signal output from the control circuit 1216. Alternatively, the notification device 1217 may be realized by a buzzer or the like.

The toothbrush portion 1220 includes a neck 1221 connected to the main body portion 1210 and a toothbrush head 1222 provided at the tip of the neck 1221. The neck 1221 and the toothbrush head 1222 are provided with a light guide path 1223 so that one end is connected to the coaxial optical system 1214 and the other end is located on one side of the toothbrush head 1222.

The coaxial optical system 1214 corresponds to the incident structure portions 110 and 710 of the light of each of the above-described embodiments, and includes the light guide path 102 and the spherical lens 103.

The toothbrush head 1222 supports one end of a plurality of fibers (hair bundles) 1224. The light guide path 1223 is arranged so that the other end (hereinafter referred to as “sensor head”) 1223a located on the toothbrush head 1222 side is located between a plurality of fibers 1224 supported by the toothbrush head 1222. The sensor head 1223a is positioned at a position recessed toward the root side of the tips of the plurality of fibers 1224 supported by the toothbrush head 1222. The light guide path 1223 emits the excitation light emitted from the coaxial optical system 1214 from the sensor head 1223a to the outside of the plaque detecting toothbrush 1200.

For example, when a plurality of fibers 1224 supported by the toothbrush head 1222 are used while being abutted against the user's tooth, the excitation light emitted from the sensor head 1223a to the outside of the plaque detection toothbrush 1200 is applied to the tooth. .. When the teeth are irradiated with excitation light, substances that form the teeth (such as enamel and dentin collagen) are excited, and fluorescence is generated from the teeth.

When plaque is attached to the teeth, when light A (wavelength 405 nm) and light B (wavelength 465 nm) of the light source 101 (101a, 101b) are irradiated, fluorescence having a peak in the wavelength band 635 nm is generated from the plaque. .. The fluorescence generated from dental plaque is generated from protoporphyrin IX (abbreviation: PPIX), which is one of the metabolic products of bacteria contained in dental plaque. The fluorescence generated from plaque becomes small in the wavelength band around 600 nm.

Fluorescence generated from teeth and plaque is incident on the light guide path 1223 from the sensor head 1223a. The light guide path 1223 guides the fluorescence incident from the sensor head 1223a to the photodetector 1215 via the coaxial optical system 1214.

The control circuit 1216 is based on the spectrum of a predetermined wavelength range including the vicinity of the wavelength band 635 nm detected by the photodetector 1215 when the light source 101a of wavelength A and the light source 101b of wavelength B are time-divided and driven to emit light. Calculate the degree of adhesion of toothpaste.

According to the plaque detection toothbrush having the above configuration, it is possible to irradiate the teeth with light having different wavelengths in the light guide path surface with the same light intensity pattern. In addition, even if the length of the light guide path is shortened, all of these different wavelengths of light have the same light intensity pattern in the light guide path surface, and there is no difference in the light intensity distribution of each wavelength with respect to the teeth. Surface irradiation can be performed without bias in the irradiation state. And since the plastic fiber can be used for the light guide path for a short distance, the usage fee of the material that is the fluorescence emission source can be reduced and the autofluorescence can be suppressed as much as possible, and the cost and size of the plaque detection toothbrush can be reduced. It will be possible to achieve the conversion. Further, since the teeth can be irradiated with light of different wavelengths for detecting plaque without any difference in the light intensity distribution, it is possible to suppress the error and detect the plaque with high accuracy.

(Embodiment 3)
In the third embodiment, a modified example of the lens used in the above-mentioned light irradiation device will be described. Although the example of the spherical lens 103 has been described as the lens in the first embodiment and the second embodiment, the lens of the present invention is not limited to the spherical lens 103.

FIG. 13 is a diagram showing light dispersion by various lenses of the light irradiation device according to the third embodiment. 13 (a) to 13 (c) show the dispersed state of the light emitted from one of the light sources 1 (101a) arranged in the upper half of the optical axis O. FIG. 13A is a biconvex lens 103a having convex surfaces on the incident side and the outgoing side of light, respectively. FIG. 13B shows a plano-convex lens 103b having a convex surface on the incident side and a flat surface on the exit side of the light. FIG. 13C is a convex meniscus lens 103c having a concave surface on the incident side and a convex surface on the exit side of the light.

Even when the various lenses 103a to 103c shown in FIGS. 13 (a) to 13 (c) are used, the incident parallel light flux A depends on the position of the lenses 103a to 103c and is refracted. , Change the direction of travel in different angular directions. By providing these various lenses 103a to 103c to expand the incident angle range of the luminous flux A into the light guide path 102, light of two different wavelengths can be mixed and color unevenness can be eliminated. As described above, even when various lenses 103a to 103c are used, the incident angle range can be expanded in the same manner as the above-mentioned spherical lens 103.

According to the first embodiment described above, in the case of a configuration in which light from a light source having a different wavelength is incident on an optical fiber which is a single light guide path, the optical axis is deviated from the axis of the light guide path. Even if there is, a lens such as a spherical lens is arranged at the incident end of the light guide path. As a result, light of different wavelengths can be made to have a light intensity pattern approximated by a short propagation distance in the light guide path, and color unevenness can be eliminated. Then, according to the first embodiment, the length of the light guide path of the device can be shortened, and the size and cost of the entire device can be reduced. As described above, according to the first embodiment, the same region of the object can be irradiated with light of different wavelengths with the same light intensity through the light guide path, and the light guide path can be set to a shorter distance than before. It has the advantage of suppressing color unevenness.

Further, as in the second embodiment, a light-shielding portion having a predetermined size is provided on the optical axis of the light guide path at a position between a light source having a different wavelength and a lens provided at the entrance (incident end) of the light guide path. You may. Since this light-shielding part blocks light near the optical axis of the light guide path, it is possible to cut light that stays on the light axis and is not reflected or light that is reflected less frequently, and light of different wavelengths with a shorter propagation distance. It becomes possible to eliminate the color unevenness of. As a result, according to the second embodiment, the length of the light guide path of the device can be further shortened as compared with the first embodiment, and the size and cost can be reduced.

Further, as in the third embodiment, the lens provided at the entrance (incident end) of the light guide path is not limited to a spherical lens, and various lenses such as a biconvex lens, a plano-convex lens, and a convex meniscus lens can be used. By expanding the range of the incident angle of the light beam into the light guide path with any of the lenses, light of two different wavelengths can be mixed and color unevenness can be eliminated.

Lights from different wavelengths may be emitted simultaneously, or only one of the light sources may be emitted alternately. When they emit light at the same time, light of different wavelengths can be mixed without color unevenness. On the other hand, even when only one of the light sources is made to emit light, the light having an approximate light intensity distribution can be emitted from the exit (exit end) of the light guide path, and the light intensity of each wavelength can be emitted from the irradiated portion of the object. There is no difference (the irradiation state is not biased), and surface irradiation can be performed.

The present invention is not limited to application to a device that irradiates an object with light of different wavelengths through a light guide path and detects the surface state of the object by reflected light, and simultaneously emits light of different wavelengths to the light guide path. It can also be applied to a configuration in which an object is irradiated through. Even in this case, the color unevenness of the light irradiating the object can be suppressed.

As described above, the present invention is useful for a light irradiating device that irradiates an object by injecting light from a light source having a different wavelength off the axis into a single-axis light guide path. It is also suitable for light irradiation detection devices that require miniaturization, such as toothbrushes used to detect plaque in teeth.

100 Light irradiation detection device 101 (101a, 101b) Light source 102 Light guide path 103 Lens (spherical lens)
110,710 Incident structure part 704 Light-shielding part 1200 Dental plaque detection toothbrush 1210 Main body part 1211 Exterior case 1214 Coaxial optical system 1216 Control circuit 1220 Toothbrush part

Claims (8)

Multiple light sources that emit light with different wavelengths and optical axes,
A light guide path that guides the light of the plurality of light sources with a single-axis optical system, and
A lens provided between the plurality of light sources and the light guide path to expand the incident angle range of light emitted from the plurality of light sources so as to be incident on one end of the light guide path.
A light irradiation device characterized by being equipped with. It is characterized in that it is provided between the plurality of light sources and the lens, and has a light-shielding portion having a predetermined size on the optical axis of the light guide path and preventing the light from entering the light guide path. The light irradiation device according to claim 1. The light irradiation device according to claim 1, wherein the lens is a spherical lens. The light irradiation device according to claim 3, wherein the core diameter of the light guide path is the same as or smaller than the diameter of the spherical lens. The light irradiation device according to claim 2, wherein the light-shielding portion is an absorber or a reflector formed on the incident surface side of the lens. The light irradiation device according to claim 1, wherein light of a plurality of wavelengths incident from one end of the light guide path is irradiated to an object through the light guide path. It is characterized in that light of a plurality of wavelengths incident from one end of the light guide path is irradiated to the object through the light guide path, and the surface state of the target object is detected based on the reflected light from the light guide path. The light irradiation device according to claim 1. One of the plurality of light sources has a wavelength at which plaque fluoresces when the tooth as an object is irradiated, and the other light source has a wavelength at which plaque does not fluoresce when the tooth is irradiated. ,
The light irradiation device according to claim 7, further comprising a control circuit for detecting the plaque based on the difference in light intensity of the reflected light when the one and the other light sources are driven in a time-divided manner.

Images