Method and device for determining UV coverage on an irradiation target in real time

Abstract

To provide a method and a device for a real time determination of UV coverage on an irradiation target.SOLUTION: A first embodiment according to the present invention is a method for a real time determination of UV coverage on an irradiation target, which includes the steps of: irradiating an irradiation target with light right after a UV sunscreen is applied; detecting an amount of fluorescence emitted from the irradiation target in response to the light irradiation; storing the amount of fluorescence as reference data; irradiating the irradiation target with the light after prescribed time goes by, or after a prescribed stress is applied to the sunscreen; detecting an amount of fluorescence emitted from the irradiation target in response to the light irradiation and storing the amount of fluorescence as measurement data; and determining the UV coverage by dividing the amount of fluorescence of the reference data by the amount of fluorescence of the measurement data, in which the irradiation target includes at least one substance that emits the fluorescence in response to the light irradiation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method and device for determining UV coverage on an illumination target in real time. [Background technology]

[0002] Protecting an irradiation target, such as human skin, from ultraviolet light (UV protection) is important for skin health and beauty. After a formulation with UV protection, i.e., sunscreen, is applied to the irradiation target, the sunscreen is eventually removed by wiping the irradiation target with a towel or by stress to the sunscreen, such as the passage of time. To effectively protect the irradiation target, it is necessary to measure the current UV protection effect. However, because ultraviolet light is invisible to the human eye, the UV protection effect is also invisible. Therefore, consumers cannot visually inspect the extent to which the UV protection effect is maintained.

[0003] When the irradiation target is irradiated with UV light, fluorescent substances contained in the irradiation target, such as collagen, NADPH, and amino acids, emit fluorescence in the visible range, for example. The amount of UV light reaching the irradiation target, in other words, the UV protection effect of a sunscreen applied to the irradiation target, can be determined by measuring the amount of fluorescence.

[0004] A conventional method for determining UV protection effectiveness includes the following steps: First, UV light is irradiated onto an irradiation target before sunscreen application, and the amount of emitted fluorescence is stored as a baseline value. Next, UV light is irradiated onto the irradiation target after sunscreen application, and the amount of emitted fluorescence is stored as a measured value. The UV light striking the irradiation target is absorbed and / or scattered by the sunscreen, resulting in a decrease in the amount of fluorescence emitted and measured from the irradiation target. The decrease in the measured value compared to the baseline value is determined as UV coverage. After a predetermined time has passed since the sunscreen was applied, or after a predetermined stress, such as wiping with a paper towel, is applied to the sunscreen, the decrease in the measured value compared to the baseline value becomes smaller, due to, for example, less sunscreen being applied. Therefore, the UV protection effectiveness of a sunscreen can be evaluated from UV coverage.

[0005] However, it has been found that even a slight decrease in the UV protection of a sunscreen can have a noticeable effect on the illuminated target. For example, an SPF 50+ sunscreen has a UV coverage greater than 98%, and an SPF 30+ sunscreen has a UV coverage greater than 95%. Although the difference in UV coverage between an SPF 50+ sunscreen and an SPF 30+ sunscreen is very small, the amount of UV light reaching the illuminated target can be more than twice as great from the user's perspective. Therefore, a more user-oriented method of determining changes in UV coverage of an illuminated target is needed to provide users with more accurate and intuitive information. Summary of the Invention [Means for solving the problem]

[0006] The present invention provides a method and device for determining UV coverage on an illumination target in real time.

[0007] A first embodiment according to the present invention is a method for determining UV coverage on an illumination target in real time, comprising: irradiating the irradiation target with light immediately after applying the sunscreen; detecting an amount of fluorescence emitted from the illumination target in response to the light illumination and storing the amount of fluorescence as reference data; irradiating the irradiation target with light after a predetermined time has elapsed or after applying a predetermined stress to the sunscreen; detecting an amount of fluorescence emitted from the illumination target in response to the light illumination and storing the amount of fluorescence as measurement data; determining UV coverage by dividing the amount of fluorescence in the reference data by the amount of fluorescence in the measured data; The method is provided wherein the illumination target comprises at least one substance that emits fluorescence in response to light illumination.

[0008] According to a first embodiment of the present invention, the reference data and measurement data may be raw data output from the sensor or may be normalized by the root mean square of the amount of fluorescence detected over a predetermined wavelength range.

[0009] According to a first embodiment of the present invention, the light irradiated onto the irradiation target may be ultraviolet light in the UV-A or UV-B wavelength range.

[0010] According to a first embodiment of the present invention, the method may further comprise the step of presenting the determined UV coverage to a user as a color representation.

[0011] According to a first embodiment of the present invention, the method may further comprise the step of presenting an alert to the user to reapply sunscreen when UV coverage is below a predetermined threshold.

[0012] According to a first embodiment of the present invention, the irradiation target may be a dummy sample comprising at least one substance contained in human skin that emits fluorescence in response to irradiation with ultraviolet light, or the irradiation target may be human skin.

[0013] A second embodiment according to the invention is a device for determining UV coverage in real time, comprising: a light source that irradiates light onto an irradiation target, the irradiation target being coated with a sunscreen; an optical sensor for detecting the amount of fluorescence emitted from the illuminated target in response to illumination with light; a control unit for controlling the light source and the optical sensor; the control unit is configured to store, as reference data, an amount of fluorescence emitted from the illumination target in response to light irradiation immediately after applying the sunscreen on the illumination target; the control unit is configured to store as measurement data an amount of fluorescence emitted from the illumination target in response to illumination with light after a predetermined time has elapsed since application of the sunscreen or after application of a predetermined stress on the sunscreen; the control unit is configured to determine UV coverage by dividing an amount of fluorescence in the reference data by an amount of fluorescence in the measurement data; A device is provided in which the illumination target includes at least one material that emits fluorescence in response to light illumination.

[0014] According to a second embodiment of the present invention, the control unit may be configured to use raw data output from the optical sensor as reference data and measurement data, or may be configured to normalize the reference data and measurement data by the root mean square of the amount of fluorescence detected over a predetermined wavelength range.

[0015] According to a second embodiment of the invention, the light source may be configured to emit ultraviolet light in the UV-A or UV-B wavelength range.

[0016] According to a second embodiment of the invention, the device may further comprise a display unit configured to present the determined UV coverage as a color representation to a user.

[0017] According to a second embodiment of the present invention, the control unit may be configured to alert the user to reapply sunscreen when UV coverage is below a predetermined threshold.

[0018] According to a second embodiment of the present invention, the irradiation target may be a dummy sample comprising at least one substance contained in human skin that fluoresces in response to irradiation with ultraviolet light, or the irradiation target may be human skin. [Effects of the Invention]

[0019] According to embodiments of the present invention, a method and device are provided for determining UV coverage on an illumination target in real time. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram illustrating a device for determining UV coverage according to an embodiment of the present invention. [Figure 2] 1 is a schematic flow chart illustrating a method for determining UV coverage in accordance with the present invention. [Figure 3] FIG. 10 illustrates the change in UV coverage measured by a method for determining UV coverage according to an embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a display unit of a device for determining UV coverage, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] As shown in FIG. 1 , a device 1 for determining UV coverage according to some embodiments of the present invention may include a light source 2, an optical sensor 6, and a control unit 8 for controlling the light source 2 and the optical sensor 6. The light source 2 may emit light 16, including ultraviolet light, to illuminate an illumination target 10. The illumination target 10 may include at least one substance that emits fluorescence in response to light, particularly ultraviolet light. Fluorescence light 20 emitted from the illumination target 10 may impinge on the optical sensor 6. The optical sensor 6 may detect the amount of fluorescence 20. If light of a wide wavelength range, such as light 16 reflected and / or scattered on the illumination target 10 or ambient light, impinges on the optical sensor 6, noise or an increased background signal may occur. This may reduce the signal-to-noise ratio of the detected signal. Therefore, a filter (not shown) for passing only light having a predetermined wavelength range may be attached to the optical sensor 6 or disposed between the optical sensor 6 and the illumination target 10. The filter may pass light in a wavelength range that includes the wavelength of the fluorescent light 20, for example, a wavelength range between 390 nm and 500 nm.

[0022] The light source 2 may emit light 16 including ultraviolet light. For example, the light source 2 may emit light having a wide wavelength range including ultraviolet light, visible light, and infrared light. Alternatively, the light source 2 may emit only ultraviolet light. For example, the light source 2 may be a ultraviolet LED that emits monochromatic ultraviolet light having a UV-A or UV-B wavelength, or more specifically, ultraviolet light having a wavelength of 365 nm. Because such ultraviolet LEDs have low power consumption and a small form factor, ultraviolet LEDs are advantageously incorporated into portable and / or handheld devices. If the light 16 is reflected and / or scattered on the illumination target 10 and strikes the optical sensor 6, noise or an increased background signal may be generated. Therefore, the light source 2 may optionally include a filter that passes only light having a required wavelength range. Furthermore, to prevent the light 16 reflected on the illumination target 10 from striking the optical sensor 6, the light source 2 and the optical sensor 6 may each optionally include a polarizing filter.

[0023] The illumination target 10 may be, for example, human skin. Human skin includes at least one fluorescent substance that may emit, for example, fluorescence in the visible wavelength range in response to irradiation with light, particularly ultraviolet light. Such a substance may be, for example, collagen, NADPH, amino acids, etc. Alternatively, the illumination target 10 may be a dummy sample containing a fluorescent substance similar to that contained in human skin, such as pig skin, cultured human skin, and a human skin model gel.

[0024] A sunscreen 12 may be applied to the illumination target 10. The sunscreen 12 may include materials that absorb and / or reflect ultraviolet light.

[0025] The device 1 may include a display unit 22. The display unit 22 may have a function of presenting the measurement results to the user, for example. The display unit 22 may be controlled by the control unit 8.

[0026] In the following, a method 100 for determining UV coverage using a device 1 for determining UV coverage having such a configuration will be described with reference to FIG.

[0027] In step 102 , an illumination target 10 , for example human skin, is illuminated with light 16 emitted from a light source 2 immediately after application of sunscreen 12 .

[0028] In step 104, the illumination target 10 may emit fluorescent light in response to illumination with light, particularly ultraviolet light. The fluorescent light may have a wavelength in the visible range, for example.

[0029] In step 106, the amount of fluorescence emitted from the illumination target 10 is detected by the optical sensor 6. The optical sensor 6 may, for example, detect the amount of fluorescence in a predetermined wavelength range.

[0030] In step 108, the control unit 8 stores the amount of fluorescence detected by the optical sensor 6 as reference data. The amount of fluorescence may be normalized, for example, by the root mean square (RMS) of the amount of fluorescence detected over a predetermined wavelength range. Alternatively, the raw data output from the optical sensor 6 may be used as reference data.

[0031] In step 110, light 16 emitted from light source 2 is irradiated onto irradiation target 10 after a predetermined time has elapsed since application of the sunscreen or after a predetermined stress has been applied to sunscreen 12. The predetermined stress may be, for example, wiping with a paper towel and / or washing with water.

[0032] In step 112, the illumination target 10 emits fluorescent light in response to illumination with light, particularly ultraviolet light. The fluorescent light may have a wavelength in the visible light range, for example.

[0033] In step 114 , the amount of fluorescence emitted from the illumination target 10 is detected by the optical sensor 6 .

[0034] In step 116, the control unit 8 stores the amount of fluorescence detected by the optical sensor 6 as measurement data. The amount of fluorescence may be normalized, for example, by the root mean square (RMS) of the amount of fluorescence detected over a predetermined wavelength range. Alternatively, the raw data output from the optical sensor 6 may be used as measurement data.

[0035] In step 118, the control unit 8 determines the UV coverage by dividing the reference data by the measured data.

[0036] In step 120, the control unit 8 causes the display unit 22 to display the UV coverage. The display of the UV coverage may be performed, for example, by displaying a value. A graph may also be displayed. A color display may be displayed by a graph having multiple predetermined colors so that the user can understand the results more clearly and intuitively.

[0037] Thus, the method illustrated in FIG. 2 may determine UV coverage on the irradiation target 10 in real time.

[0038] For example, the light 16 irradiating the irradiation target 10 is blocked by the sunscreen 12 immediately after application, so the amount of detected fluorescence, i.e., the reference data, has a significantly small value. The UV coverage may be 100% because it is determined by dividing the reference data by itself. After a certain amount of time has passed since application of the sunscreen and / or after a certain stress has been applied to the sunscreen 12, the effectiveness of the sunscreen 12 in blocking the light 16 may decrease. Therefore, the amount of detected fluorescence, i.e., the measured data, increases. Because the reference data is divided by the measured data, the UV coverage will be a value less than 100%. If the effectiveness of the sunscreen 12 decreases, the UV coverage will decrease.

[0039] Table 1 shows a comparison of UV coverage measured by a conventional method and by a method according to an embodiment of the present invention immediately after application of sunscreen 12 and after a predetermined stress. The irradiation target 10 in Table 1 is a human forearm. Measurements were performed on five subjects, and the average values ​​of the measurements were used as data. PA++++ O / W SPF 50+ sunscreen 12 was applied at 2.0 mg / cm 2 was applied to the irradiation target 10. O / W sunscreen refers to a formulation in which oil is dispersed in water. The first and second stresses are wipes with a dry paper towel. The third stress is wipes with alcohol. The UV coverage by the conventional method is calculated by the following formula:

[0040]

number

[0041] In the above equation, x0 is the amount of fluorescence before applying sunscreen, and x mes is the fluorescence measurement at each step, for example, immediately after applying sunscreen or after the first, second, or third stress.

[0042] The UV coverage according to the method of the present invention is given by the following formula:

[0043]

number

[0044] In the above equation, x i is the amount of fluorescence immediately after applying sunscreen, and x mes is the measured fluorescence at each step, e.g., after the first, second, or third stress.

[0045] [Table 1]

[0046] The difference between the UV coverage immediately after applying the sunscreen and the UV coverage after the first stress, obtained by the conventional method, was 22.91 points, while the difference between the UV coverage immediately after applying the sunscreen and the UV coverage after the first stress, obtained by the method according to the present invention, was 48.74 points. It can be said that the sensitivity of the present invention to the decrease in UV coverage is more than twice that of the conventional method. Therefore, the method according to the present invention can evaluate the change in UV coverage caused by the application of stress with higher sensitivity. In other words, the method according to the present invention can evaluate the increase in the impact of UV light reaching the irradiation target 10, for example, human skin, caused by the decrease in the effectiveness of the sunscreen with higher sensitivity. Since the presence or absence of skin damage due to exposure to UV light is a major concern for users, the UV coverage obtained by the method according to the present invention, which can monitor the increase in UV light, may be a more user-oriented evaluation index for users to understand and use, compared to conventional UV coverage assessment methods based on blocked UV light or the decrease in UV light compared to bare skin.

[0047] FIG. 3 shows graphs illustrating the change in UV coverage obtained by the method of the present invention. FIGS. 3(a) and 3(b) show measurements on the cheek and forehead of a human face, respectively, where sunscreens of Type A and Type B formulations were applied. Type A is a formulation in which oil is dispersed in water (called an O / W type) and is mostly water. Type B is a formulation in which water droplets are dispersed in a continuous oil phase (called a W / O type). These are two representative flowable formulations commonly found on the market. TO represents the measurement result before applying the sunscreen. T1 represents the measurement result immediately after applying the sunscreen. T2 represents the measurement result after spraying water to simulate the stress of getting wet after applying the sunscreen. T3 represents the measurement result after 10 minutes of cycling. T4 represents the measurement result after wiping with a paper towel. As shown in FIGS. 3(a) and 3(b), it can be seen that UV coverage can be reproducibly measured on any area of ​​the face and at any stage. The results shown in Figures 3(a) and 3(b) show that the UV coverage of Type B sunscreen is slightly higher than that of Type A sunscreen, but this difference is substantially within the margin of error. Thus, the device and method of the present invention can reproducibly measure the UV coverage of any type of sunscreen formulation.

[0048] Figure 4 shows an example of a device 1 for determining UV coverage, according to some embodiments of the present invention. Figure 4(a) shows a schematic exterior view of device 1, and Figures 4(b) and 4(c) are exemplary diagrams of a display unit 22 of device 1. Display unit 22 may be appropriately shaped for aesthetic reasons to match the shape of enclosure 24 of device 1. In the example shown in Figure 4, display unit 22 has a circular shape because display unit 22 is disposed on the top surface of the generally cylindrical enclosure 24, but is not limited to this shape.

[0049] The device 1 may display the determined UV coverage to the user via the display unit 22. For example, the UV coverage may be displayed as a value shown in Table 1. Alternatively, the UV coverage may be provided as multiple levels, such as A, B, and C, so that the user can more intuitively understand the results. Alternatively, the color indication may be displayed as a color-coded graph. FIG. 4(b) shows high UV coverage, e.g., immediately after applying sunscreen. The display unit 22 indicates the UV coverage level as "A" and displays a color indication of a complete ring. FIG. 4(c) shows a state in which the UV coverage has decreased compared to FIG. 4(b). The UV coverage level is "B" and is displayed as a color indication with a missing part of the ring. Using such a display, the user can easily and intuitively inspect the change in UV coverage and recognize the status of the sunscreen.

[0050] Furthermore, device 1 may present an alert to the user, for example, when the determined UV coverage is lower than a predetermined threshold. For example, the alert may be embodied by an audible or visual display on display unit 22, or a display on the user's smartphone via a network. The alert may warn the user that the effectiveness of the sunscreen is decreasing and that the sunscreen should be reapplied.

[0051] While specific embodiments of the present invention have been described, it will be readily apparent to those skilled in the art that various changes, modifications, and improvements can be made without departing from the spirit and scope of the invention. [Explanation of symbols]

[0052] 1. Device for determining UV coverage 2 light source 6 Optical Sensor 8. Control Unit 10 Irradiation Target 12. Sunscreen 16 light 20 Fluorescence 22 Display unit 24 Enclosure

Claims

1. 1. A method for determining UV coverage on an irradiation target in real time, comprising: irradiating the irradiation target with light immediately after applying the sunscreen; detecting an amount of fluorescence emitted from the illumination target in response to the light illumination and storing the amount of fluorescence as reference data; irradiating the irradiation target with light after a predetermined time has elapsed or after applying a predetermined stress to the sunscreen; detecting an amount of fluorescence emitted from the illumination target in response to the light illumination and storing the amount of fluorescence as measurement data; determining a reduction in UV coverage by dividing the amount of fluorescence in the reference data by the amount of fluorescence in the measurement data and subtracting the resulting value from one; The method, wherein the illumination target comprises at least one material that emits fluorescence in response to the light illumination.

2. 2. The method of claim 1, wherein the reference data and the measurement data are raw data output from a sensor or root mean square normalized data of the amount of fluorescence detected over a predetermined wavelength range.

3. The method of claim 1 , wherein the light irradiated onto the irradiation target is ultraviolet light in the UV-A or UV-B wavelength range.

4. The method of claim 1 , further comprising presenting the determined UV coverage to a user as a color representation.

5. The method of claim 1 , further comprising the step of presenting an alert to a user to reapply the sunscreen when the UV coverage is below a predetermined threshold.

6. 2. The method of claim 1, wherein the irradiation target is a dummy sample including at least one substance contained in human skin that emits fluorescence in response to irradiation with ultraviolet light, or the irradiation target is human skin.

7. 1. A device for determining UV coverage in real time, comprising: a light source for irradiating an irradiation target with light, wherein a sunscreen is applied to the irradiation target; an optical sensor for detecting the amount of fluorescence emitted from the illumination target in response to the light illumination; a control unit for controlling the light source and the optical sensor; the control unit is configured to store as reference data the amount of the fluorescence emitted from the illumination target in response to the light irradiation immediately after applying the sunscreen on the illumination target; the control unit is configured to store as measurement data the amount of fluorescence emitted from the illumination target in response to the light illumination after a predetermined time has elapsed since application of the sunscreen or after a predetermined stress has been applied to the sunscreen; the control unit is configured to determine the reduction in UV coverage by dividing the amount of fluorescence in the reference data by the amount of fluorescence in the measurement data and subtracting the result from one; The device, wherein the illumination target comprises at least one material that emits fluorescence in response to the light illumination.

8. 8. The device of claim 7, wherein the control unit is configured to use raw data output from the optical sensor as the reference data and the measured data, or to normalize the reference data and the measured data by the root mean square of the amount of the fluorescence detected over a predetermined wavelength range.

9. The device of claim 7 , wherein the light source is configured to emit ultraviolet light in the UV-A or UV-B wavelength range.

10. The device of claim 7 , further comprising a display unit configured to present the determined UV coverage as a color representation to a user.

11. 8. The device of claim 7, wherein the control unit is configured to alert a user to reapply the sunscreen when the UV coverage is below a predetermined threshold.

12. 8. The device of claim 7, wherein the irradiation target is a dummy sample including at least one substance contained in human skin that emits fluorescence in response to irradiation with ultraviolet light, or the irradiation target is human skin.

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