TW201326736A - Light detector for sunscreen thickness measurement and method thereof - Google Patents

Abstract

The present invention discloses a light detector for sunscreen thickness measurement and the method thereof, specifically to a non-ultraviolet light sensing device collecting non-ultraviolet light reflection intensity data from the surface of the human skin. The device eliminates the effect of different skin tone has from different people by subtracting the light intensity detected before the application of the sunscreen from the light intensity detected after the application of the sunscreen.

Description

Light sensing device for measuring thickness of sunscreen lotion and method thereof

The present invention relates to a light sensing device for a sunscreen lotion and a method therefor.

Ultraviolet rays (wavelength: 290 ~ 400nm) in sunlight contain different wavelength bands, among which UVB (wavelength: 290 ~ 315nm) has weaker ability to penetrate the skin, but the energy is strong, so it is easy to cause sunburn or burn on the surface of human skin, so For the general purpose of high sun protection factor (SPF) coefficient sunscreen lotion to be isolated. There are two principles of sun protection: using sunscreen lotion to reflect light from the sun, or using sunscreen lotion to absorb light to prevent direct contact with human skin. Generally, the identification of sunscreen lotion ability is based on the above sun protection principle, and the amount of penetration, absorption, or reflection of ultraviolet light is measured by the interaction of ultraviolet light and sunscreen lotion components.

Measuring the amount of ultraviolet light penetration is applied to the front side of a glass or light-transmissive test piece, and the ultraviolet light is irradiated from above the front surface, and the photoreceptor is placed on the back side of the glass or the test piece to perform integral operation of the transmitted light. The measurement of the amount of ultraviolet light absorption is calculated by using the total energy absorbed by the photosensitive wafer per unit time. Since the two measures the amount of UV light penetration and absorption, and both are directly irradiated with ultraviolet light, it is impossible to directly apply the sunscreen lotion to the surface of the human skin. Since the penetration measurement fails to consider that the glass or the light-transmissive test piece also absorbs the characteristics of ultraviolet light, it may cause the same amount of penetration of the sunscreen lotion with different SPF coefficients, that is, the same sunscreen effect, in terms of accuracy. Still controversial.

In addition to the above identification methods, tests for directly applying sunscreen lotions to human skin have also been developed. US Patent Application Publication No. US20100226861 A1 considers the resistance of individual skin color differences to ultraviolet light doses, and the difference in different sunscreen lotions, thus developing a sunscreen emulsion that is doped with a fluorescent chromophore, which is emulsion soluble. And has an absorption peak greater than 400 nm. The invention is characterized in that the amount of sunscreen lotion on the skin is calculated by detecting the excitation light emitted by the fluorescent molecule at another longer wavelength following the Stoke's shift. Unlike the transmissive or absorptive measurements described above, this reflective measurement removes the effect of differences in individual skin color and sunscreen lotion composition on the measurement results, resulting in a pure amount of sunscreen lotion. However, this fluorescent molecule is not doped into a commercially available sunscreen lotion, and thus the usability is limited.

U.S. Patent No. 4,629, 910 discloses a sunscreen lotion device which requires the user to input their skin tone by themselves, and the device will give the user a warning of sunburn in accordance with the dose of ultraviolet light at that time. It can be seen that when the test is carried out on human skin coated with a sunscreen lotion, the difference in individual skin color affects the interpretation of the sunburn warning. The above invention takes this into consideration, and the user selects and inputs his own skin color among the six skin color gradations to calculate the resistance to the ultraviolet light dose. However, the difficulty in use is that the user does not necessarily be able to determine his skin tone rating by himself. Therefore, a sunscreen device that completely removes skin color differences and does not require additional fluorescent molecules in the sunscreen lotion will greatly improve the usability and accuracy.

One embodiment of the present invention discloses a light sensing device for a sunscreen lotion comprising: a non-ultraviolet light source, a light sensor, a control and logic unit, a switch, and a display unit. The non-ultraviolet light source directly illuminates the human skin, and the photo sensor senses a reflection intensity analog signal of the non-ultraviolet light source on the human skin; the control and logic unit includes a microprocessor and a switch, wherein the microprocessor Converting the reflection intensity analog signal into a digital signal and storing the digital signal, the switch switches a reflection intensity information processing mode; the display unit displays the operation result in the microprocessor.

Another embodiment of the present invention discloses a light sensing device including a non-ultraviolet light source, a light sensor, a control and logic unit, and a display unit. The non-ultraviolet light source illuminates the human skin; the light sensor senses a reflection intensity of the non-ultraviolet light source on the human skin; the control and logic unit includes an amplifying unit and a skin tone regulating unit configured to amplify the light sensation The analog signal from the detector determines the voltage at a second input; the display unit displays the result of the signal in the control and logic unit.

The technical features and advantages of the present disclosure have been broadly described above, and the detailed description of the present disclosure will be better understood. Other technical features and advantages of the subject matter of the claims of the present disclosure will be described below. It will be appreciated by those skilled in the art that the present invention may be practiced with the same or equivalents. It is also to be understood by those of ordinary skill in the art that this invention is not limited to the spirit and scope of the disclosure as defined by the appended claims.

The invention estimates the thickness of the sunscreen lotion 13 on the surface of the human skin by measuring the reflection intensity of a non-ultraviolet light. One reason for selecting the non-ultraviolet light is to prevent the ultraviolet light from directly illuminating the human skin. Figure 1 is a schematic enlarged view of the surface of a human skin 10, wherein the skin layer 11 is coated with a sunscreen lotion 13 which is invisible to the naked eye. When the sunlight 15 is irradiated, the ultraviolet rays, especially the UVB band, are reflected in the following material interfaces. , absorption, and penetration: 1) interface of air with the sunscreen lotion 13, 2) interface of the sunscreen lotion 13 with the skin layer 11. The intensity of the reflected light measured in the case of Fig. 1 is the sum of the reflected light intensities occurring in the above 1) and 2) interfaces. If the same measurement is performed on the surface of the human body to which the sunscreen lotion 13 has not been applied, the intensity of the reflected light corresponding to the above 2) interface is obtained, and the intensity of the reflected light of the human body surface to which the sunscreen lotion 13 is applied is subtracted from the surface reflected light of the human body before the application. Intensity, the intensity of the reflected light contributed by the sunscreen lotion 13 alone can be obtained. This intensity corresponds to the thickness of a particular sunscreen lotion 13. The thicker the sunscreen lotion, the stronger the intensity of the reflected light, allowing the user to know if the remaining sunscreen lotion 13 thickness still has sufficient sun protection.

As shown in FIG. 2, a light sensing device 20 of the present invention has a non-ultraviolet light source 21 and a photo sensor 22 corresponding to the non-ultraviolet light source 21, the photo sensor 22 having the largest band in the non-ultraviolet light source 21 The quantum efficiency, and the photosensor receives non-ultraviolet light 25 that is reflected by the human skin layer 11 (with or without the sunscreen lotion 13 applied). The analog signal (ie, current) generated by the photo sensor 22 enters a control and logic unit 23. After the user selects the information processing mode, the control and logic unit 23 performs a logic operation, and the operation result in the processing mode Will be output and displayed on a display24.

An embodiment of the invention discloses a light sensing device as shown in FIG. 3, wherein the non-ultraviolet light source 30 of FIG. 3 is a light emitting element having a wavelength of 430-550 nm. Before the application of the sunscreen lotion, the user needs to move a switch 31 located in a control and logic unit 33 to the reflection intensity information processing mode (1) 31a. When the non-ultraviolet light enters the light sensor 32, the Light sensor 32 will generate a first reflected intensity signal. This first reflection intensity analog signal (current) will be passed to a microprocessor 35 for logic operation. The microprocessor 35 of this embodiment performs a storage step and a comparison step in the reflection intensity information processing mode (1). One of the analog/digital conversion (ADC) units 35a digitizes the signal and stores it in a memory 35b. When a liquid crystal screen 34a on the display 34 displays an English letter (shown as P in FIG. 3), it means that the device has finished detecting the skin color of the user, and the user can apply the sunscreen lotion and proceed to the next step. . The memory 35b pre-stores a database of reflection intensities of different skin colors at different light intensities, and the measurement signals are compared with the database to complete the skin color interpretation.

In this embodiment, the skin color of the human body is roughly divided into six grades according to the number of melanin pigments, for example, pale, fair, medium, orange, dark, black. (black). As shown in FIG. 3, the liquid crystal screen 34a displays the English letter P, that is, the result of the user's skin color interpretation is pale. According to the above six skin color classifications, other possible letters are: F, M, O, D, and B.

When the user applies the sunscreen lotion and moves the switch 31 to the reflection intensity information processing mode (2) 31b, the photo sensor 32 generates a second reflection intensity signal through the same non-ultraviolet light reflection intensity measurement. Similarly, the second reflection intensity analog signal (current) will be passed to a microprocessor 35 for logic operation. The microprocessor 35 performs a subtraction operation here, subtracting the first reflected intensity signal previously stored in the memory 35b from the second reflected intensity signal, and converting the result into a sunscreen lotion thickness and displaying A number is on a liquid crystal screen 34b on the display 34. An Arabic numeral 5 is shown in Fig. 3 on the liquid crystal screen 34b, representing a sunscreen emulsion thickness of 20 microns after conversion. Based on this information, the user can judge whether the sunscreen lotion 13 needs to be thickened to ensure the sunscreen effect. In this embodiment, the non-ultraviolet light source 30 used for the measurement before and after the application of the sunscreen lotion has the same wavelength.

If the user is the same person, the skin color interpretation in the embodiment only needs to be performed once at the time of initial use, and the second or subsequent sunscreen lotion thickness measurement only needs to maintain the switch 31 in the reflection intensity information processing mode (2), that is, Measurements can be made.

An embodiment of the invention discloses a light sensing device as shown in FIG. 4, wherein the non-ultraviolet light source 40 of FIG. 4 is a light emitting element having a wavelength of 430-550 nm. The control and logic unit 43 of FIG. 4 includes a primary differential amplifier 45 and a set of secondary differential amplifiers 46. The user needs to modulate a skin tone control knob 47 located in a control and logic unit 43 to reflect the resistance setting of the device. As shown in FIG. 4, the skin tone control knob 47 has six light to dark color patches representing the settings of different skin tones. When the user rotates the skin tone control knob 47, the variable resistor R1 is substantially adjusted, and the effective voltage of a second input terminal 45b of the main differential amplifier 45 is also modulated. Since the skin tone control knob 47 performs a continuous resistance modulation, the user's skin tone will be precisely defined, rather than being roughly classified into any of the six levels.

When the non-ultraviolet light generates a first reflection intensity from the human skin from which the sunscreen lotion is not applied, the photo sensor 42 generates an analog signal to enter a first input of the main differential amplifier 45. 45a. The skin color interpretation is based on the fact that when the main differential amplifier 45 performs a differential operation, the result is zero, that is, when the voltage V1 of the first input terminal 45a is equal to the voltage V2 of the second input terminal 45b, the difference is The result of the operation obtained by the amplifier 45 is zero. At this time, no signal enters the secondary differential amplifier 46, so the skin color determination light 44a on the display 44 lights up, indicating that the user's skin color interpretation step is completed.

After the skin color interpretation step is completed, the user can apply the sunscreen lotion and perform the step of measuring the thickness of the sunscreen lotion. When the non-ultraviolet light rays generate a second reflection intensity from the human skin to which the sunscreen lotion is applied, the photo sensor 42 generates an analog signal to enter a first input end of the main differential amplifier 45. 45a, generating a voltage V1. At this time, the voltage V2 of the second input terminal 45b still maintains the result of the previous skin color interpretation. Therefore, the main differential amplifier 45 performs a differential operation result, that is, the gain value and (V1-V2). The product of this will enter the secondary differential amplifier 46 for step division. Then one of the sunscreen lotion indicator light 44b on the display 44 will illuminate to inform the user if the thickness of the sunscreen lotion applied is too thin, for example, less than 2 microns; or moderately, for example, between 2 microns and 20 Between microns; or safe, for example, greater than 20 microns. In the present embodiment, the non-ultraviolet light source 40 used for the measurement before and after the application of the sunscreen lotion is the same wavelength.

If the user is the same person, the skin color interpretation stage in the embodiment only needs to be performed once at the time of initial use, and the second or subsequent measurement only needs to maintain the skin color adjustment knob 47 at the original position, and the measurement can be performed.

Figure 5 shows experimental data for the relative reflectance of different brands of sunscreen lotions for different wavelengths. The relative reflectance of different brands of sunscreen lotions is almost the same in the wavelength range of 430-550 nm. Therefore, non-ultraviolet light sources can use blue or green light-emitting elements. Since the light-emitting element is small in size, power-saving, and long in service life, it is suitable for integration with a photo sensor in the embodiment of the present invention, such as a photodiode or a cadmium sulfide (CdS) photoresistor, and a circuit.

The technical content and the technical features of the present disclosure have been disclosed as above, but those skilled in the art should understand that the teachings and disclosures of the present disclosure are disclosed without departing from the spirit and scope of the disclosure as defined by the appended claims. Can be used for various substitutions and modifications. For example, many of the processes disclosed above may be implemented in different ways or in other processes, or a combination of the two.

Moreover, the scope of the present invention is not limited to the particular process, machine, manufacture, composition, means, method or method of the particular embodiments disclosed. It should be understood by those of ordinary skill in the art that, based on the teachings of the present disclosure, the process, the machine, the manufacture, the composition of the material, the device, the method, or the steps, whether present or future developers, The revealer performs substantially the same function in substantially the same manner, and achieves substantially the same result, and can also be used in the present disclosure. Accordingly, the scope of the following claims is intended to cover such <RTIgt; </ RTI> processes, machines, manufactures, compositions, devices, methods or steps.

10. . . hand

11. . . Skin layer

13. . . Sunscreen lotion

15. . . sunlight

20. . . Light sensing device

21, 30, 40. . . Non-ultraviolet light source

22, 32, 42. . . Light sensor

23, 33, 43. . . Control and logic unit

24, 34, 44. . . monitor

25. . . Non-ultraviolet light

31. . . switch

31a. . . Reflection intensity information processing mode (1)

31b. . . Reflection intensity information processing mode (2)

34a, 34b. . . LCD screen

35. . . microprocessor

35a. . . Analog/digital conversion unit

35b. . . Memory unit

44a. . . Skin color determination indicator

44b. . . Sunscreen smear indicator

45. . . First stage differential amplifier

45a. . . First input

45b. . . Second input

46. . . Second stage differential amplifier

47. . . Skin tone control knob

Figure 1 shows a schematic view of a human hand skin coated with a sunscreen lotion;

2 is a block diagram showing the main part of a light sensing device;

3 shows a block diagram of an optical sensor, control and logic unit, and display of an embodiment;

4 shows a block diagram of a photosensor, control and logic unit, and display of another embodiment;

Figure 5 shows experimental data for the relative reflectance of different brands of sunscreen lotions for different wavelengths.

11. . . Skin layer

13. . . Sunscreen lotion

20. . . Light sensing device

twenty one. . . Non-ultraviolet light source

twenty two. . . Light sensor

twenty three. . . Control and logic unit

twenty four. . . monitor

25. . . Non-ultraviolet light

Claims (13)

A light sensing device for measuring the thickness of a sunscreen lotion, comprising: a non-ultraviolet light source configured to illuminate human skin; and a light sensor configured to sense a reflection intensity of the non-ultraviolet light source on human skin Analog signal; a microprocessor comprising: a analog/digital conversion unit configured to convert a reflected intensity analog signal into a digital signal; and a memory unit configured to store the digital signal; a switch configured to switch a reflection intensity information processing mode, wherein the processing mode comprises: a first mode, storing a first reflection intensity information into the memory unit; and a second mode, storing a second reflection intensity information in the memory unit The first reflection intensity information is subtracted to produce an operation result; and a display unit configured to display an operation result in the microprocessor. The light sensing device of claim 1, wherein the non-ultraviolet light source is a light emitting element having a wavelength between 430 nm and 550 nm. The light sensing device of claim 2, wherein the first reflection intensity information is generated by the light source and a human skin that is not coated with a sunscreen lotion, wherein the second reflection intensity information is smeared by the light source and the smear The sunscreen lotion is produced by the same human skin action. The light sensing device of claim 2, wherein the display unit displays at least one skin color information and the reflected intensity of the non-ultraviolet light source on the human skin. A light sensing device for measuring the thickness of a sunscreen lotion, comprising: a non-ultraviolet light source configured to illuminate human skin; and a light sensor configured to sense a reflection intensity of the non-ultraviolet light source on human skin Analog signal; a control and logic unit comprising: an amplifying unit having a first input and a second input, configured to amplify an analog signal transmitted by the photo sensor; and a skin tone control unit configured to Adjusting the input voltage of the second input according to the skin color; and a display unit configured to display the operation result of the analog signal in the control and logic unit. The light sensing device of claim 5, wherein the display unit displays at least one skin color information and the reflection intensity analog signal of the non-ultraviolet light source on the human skin. The light sensing device of claim 5, wherein the non-ultraviolet light source is a light emitting element having a wavelength between 430 nm and 550 nm. The optical sensing device of claim 7, wherein the amplifying unit is a differential amplifier, and the step of amplifying the differential amplifier is a product of a gain value and a difference between the two input signals. The light sensing device of claim 8, wherein the skin tone control unit comprises a variable resistor. A method for measuring the thickness of a sunscreen lotion comprises the steps of: measuring a human skin without applying a sunscreen lotion to obtain a first light reflection intensity; applying a sunscreen lotion to human skin; measuring the skin of the human body by applying a sunscreen lotion Obtaining a second light reflection intensity; and subtracting the second light reflection intensity from the first light reflection intensity to obtain a thickness of the sunscreen emulsion. According to the method of claim 10, the step of measuring the first light reflection intensity comprises adjusting a variable resistance. According to the method of claim 10, the measuring step comprises using a non-ultraviolet light source and a non-ultraviolet light sensor. According to the method of claim 10, the measuring steps all use light sources of the same wavelength.