GB2261504A

GB2261504A - Regulating the exposure of a user's skin to ultraviolet radiation

Info

Publication number: GB2261504A
Application number: GB9124463A
Authority: GB
Inventors: Aharon Factor; Philip Schryber; Mark Wein
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-18
Filing date: 1991-11-18
Publication date: 1993-05-19
Also published as: GB9124463D0

Abstract

Apparatus to regulate the exposure of a user's skin to ultraviolet (UV) radiation comprises a sensor means (10, 11) to generate a signal representative of the intensity of UV radiation to which skin is exposed, a processor and warning means (19, 22). A display (19) shows the cumulative dose of UV radiation received. An alarm (22) sounds when the maximum dose (dependent on skin type and protection factor selected (50, 51)) is received. The device can advise the protection factor that should be worn, based on radiation received over a short test period. The sensor and display may be separate units, connected by cable or radio signal. <IMAGE>

Description

APPARATUS FOR USE IN REGULATING THE EXPOSURE OF A USER'S SKIN TO ULTRAVIOLET RADIATION The present invention relates to apparatus for use in regulating the exposure of a user's skin to ultraviolet radiation.

In recent times there has been much concern regarding the cancerous effects of sunlight on the skin. It has been recognised that exposure to ultraviolet light can cause skin cancer and risks are involved in long exposure to the sun for the purpose of tanning.

The present invention provides apparatus for use in regulating the exposure of a user's skin to ultraviolet (W) radiation comprising sensing means operable to generate a signal representative of the intensity of W radiation to which the skin is exposed and warning means operable in response to the signal to produce an indication to the user of action to be taken to regulate the exposure of skin appropriate to the sensed intensity.

Thus the user can regulate the exposure of his or her skin to ultraviolet radiation to minimise risks of sunburn and cancer.

In a first preferred embodiment the warning means comprises processor means for processing the signal generated by the sensing means to generate a signal corresponding to an attenuation factor of barrier means and display means for displaying to the user of the device the attenuation factor of barrier means corresponding to the signal generated by the processor means.

The present invention determines what attenuation factor of barrier means the user requires for specific intensities of sunlight.

In a second preferred embodiment the warning means comprises processor means for integrating the signal generated by the sensing means over a time period and for generating a signal corresponding to cumulative sensed W radiation, and display means which receives the signal generated by the processor means and displays to the user a display indicative of the cumulative sensed W radiation.

The present invention thus also provides means by which a person can guage how long he or she should expose his or her skin to ultraviolet radiation.

Indeed the present invention can provide a device for both recommending an attenuation factor of barrier means and also for monitoring exposure to the ultraviolet radiation.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a block diagram showing schematically a first embodiment of the invention.

Figure 2 is a block diagram showing schematically a second embodiment of the invention.

Figure 3 depicts a first preferred display for the apparatus of the invention.

Figure 4 depicts a second preferred display for the apparatus of the invention.

Figure 5 shows a first preferred selector for the apparatus of the invention.

Figure 6 shows a second preferred selector for the apparatus of the invention.

Figure 7 shows a third preferred selector for the apparatus of the invention.

Figure 8 is a block diagram showing schematically a third embodiment of the invention.

Referring to Figure 1, the preferred embodiment can be seen to comprise an ultraviolet detector 10 which is the light sensing means of the device. The ultraviolet detector 10 is a photodiode sensitive only to ultraviolet light. It has been previously determined that ultraviolet light is the cause of sunburn and is also the cause of skin cancer. In use, the user of the device will position it such that the ultraviolet detector 10 receives the same intensity of radiation as the user.

The signal output from the ultraviolet detector 10 is initially amplified by the preamplifier 11. The signal is then further amplified at 12 by a gain which is variable. The gain is varied by the user of the device via an input 50 to the device. The input 50 is a skin pigment selector. The user of the device decides what skin type he or she has and varies the skin pigment selector accordingly, thereby varying the gain of the amplifier 12.

The amplified signal produced by amplifier 12 is passed through a low pass filter 13 which limits the bandwidth of the signal to 1Hz. The output of low pass filter 13 is a frequency limited signal having a voltage proportional to the intensity of the ultraviolet light falling on the detector 12.

The output of the low pass filter 13 is received by a voltage controlled oscillator 14. The signal generated by the oscillator 14 is a signal of constant amplitude and varying frequency having a square waveform. The frequency of the signal generated by the oscillator 14 is proportional to the voltage of the output signal of the low pass filter 13.

The signal generated by oscillator 14 is transmitted to a digital divider 15. The divider 15 operates in one of two different modes depending on what selection the user makes via an input switch 16.

The user can use the switch 16 to switch the device off by disconnecting the circuit from a power source (eg. battery or solar cell) or to select one of two modes of operation which shall be called "exposure mode" and "factor mode".

In "factor mode" the device can be used to recommend an attenuation factor of barrier means (e.g.

suntan cream, suntan lotion, sun umbrella etc.) to the user, calculated on the basis of the user's skin type and the intensity of the ultraviolet radiation.

In "exposure mode" the user inputs both his or her skin type and also the attenuation factor of the barrier means used, the device calculating a recommended maximum exposure in terms of W energy received by the user (integral of intensity of sensed ultraviolet over time of exposure) and showing on an LCD screen the percentage of recommended exposure already elapsed. The device will also issue an audible warning when the user has been exposed to sunlight for the maximum recommended exposure.

In "factor mode" the number of oscillations of the output signal of the oscillator 14 for a fixed time period is calculated. This is done by gating the output of the voltage controlled oscillator 14 for the fixed time period. The number of oscillations during the fixed time period is counted by counter 17, after division by divider 18. The divider 18 divides by a suitable constant K1 such that the counter 17 counts a number of oscillations corresponding to an attenuation factor of the barrier means used by the user.

The output of the counter 17 is forwarded to a display driver 18 which then displays the recommended factor on an LCD display 19.

A clock 20 and a control logic circuit 21 are provided to facilitate operation of the divider 15, counter 17 and display driver 15.

In "exposure mode" the output of the voltage controlled oscillator 14 is not gated, but is monitored continuously. The counter 17 counts the number of oscillations of the signal generated by the voltage controlled oscillator 14 after division of the signals by a suitable constant K2 by the divider 15 and then by the attenuation factor of the barrier means used. The attenuation factor of the barrier means used is entered by the factor selector 51.

In "exposure mode" the device continually monitors the received sunlight and integrates the sensed intensity with time to output an "exposure" signal as an energy level of cumulative W radiation sensed over the time of exposure.

The counter 17 counts the number of oscillations as a percentage of a preprogrammed fixed total. The output signal of the counter 17 is then output to the display driver 18 which displays on the LCD screen 19 a figure which is the percentage of recommended exposure that has already been received. When the maximum exposure recommended is reached the counter 17 outputs a signal to a sounder 22 which issues an audible warning to the user of the device.

In the preferred embodiment of the invention the input to the voltage controlled oscillator is a signal chosen to be of a voltage varying between 0V and 4V, the voltage being proportional to the intensity of the ultraviolet radiation light incident on the photodiode and also proportional to the gain selected by the skin pigment selector. The frequency of the output of the voltage controlled oscillator is Vin*256/Vref where Vin is the input signal and Vref is 4V.

In "factor mode" the output of the VCO is gated for one second and divided by 16 by the divider. The output is then counted by the counter. Hence the output of the counter after one second is the recommended attenuation factor for the barrier means used, which in the case of suntan cream which can vary between 1 and 16.

In the "exposure mode" the output of the VCO is not gated and is divided by 2048 by the divider 1C3 and then divided by the attenuation factor of the barrier means, which is input into the counter via the selector.

The divided output is counted by the counter and the output of the counter is the percentage of recommended exposure already received (i.e. ratio of cumulative sensed W radiation to preprogrammed maximum value of cumulative UV radiation for a particular skin type). When the figure 99 is reached the counter is halted and an audible warning given by the warning device 22. The division by 2048 defines the minimum exposure duration possible to be around thirteen minutes. The maximum exposure time can be selected by varying the pre-amplification circuit, but will generally be chosen to allow a maximum of eight hours with the lowest attenuation factor setting.

In the preferred embodiment, the attenuation factor of the barrier means will be entered by the user by the binary coded decimal switch.

When the device is operating in "exposure" mode the user can continually alter the attenuation factor input to the device to take account of, for instance, removal of sun tan cream by swimming. The device alters its monitoring function accordingly during the period of removal of sun tan cream.

In a preferred embodiment the device would be provided with "swim" and "hold" functions. Buttons or switches would be provided to enable the "swim" and "hold" functions. On selection of the "swim" functions the user would switch the device to maximum sensitivity (i.e. the device would consider that a suntan protection factor 1, the lowest factor, is used). This enables the user to easily adjust the monitoring function of the device when he or she decides to swim either away from the protection of a sun shade or with only a non-waterproof skin protection lotion applied.

In addition a second "swim" function selection could be provided to enable the user to control the monitoring function of the device if he or she wishes to use a waterproof lotion only when swimming. The device would switch from using the SPF factor originally input by the user to a specific SPF factor. For this function to be effective the user would have to use waterproof lotion of a protection factor already specified for the second swim function of the device.

The "hold" function of the device would be used by the user when he or she puts on clothing or enters a building out of sunlight. The "hold" function would be selected by the user by means of a switch connected to the counter 17. On selection of the "hold" function the counter would cease counting the number of pulses of the pulsed signal it receives and would store a value equivalent to the number of pulses already received on selection of the "hold" function.

When the "hold" function is deselected by the user then the counter 17 would be enabled and would continue counting.

In Figure 2 an embodiment of the invention can be seen with a first "swim" function selector 23 for selecting maximum sensitivity, a second "sun" function selection 24 for selecting a specific SPF factor corresponding to a factor of waterproof lotion used by the user and a "hold" function switch 25 for stopping the monitoring of the ultraviolet radiation.

The "swim" function selectors are connected to the divider 15 and act as factor selectors, selecting the SPF factor used by the divider in its division process.

The "hold" function selector 25 is connected to the counter 17 and causes the counter 17 to cease counting and to hold a particular count until the "hold" function selector 25 is operated by the user to deselect the "hold" function.

In a further preferred embodiment an alarm device is incorporated in the device to warn the user should the device become covered in use. This can be simply done by incorporating a logic gate 26 connected to the output sensor 10 and mode switch 16. If the device is switched on (in either factor or exposure mode) and no or low (below a specified minimum) current or voltage is generated by the ultraviolet detector 10 then the logic circuit 26 will cause the sounder 22 to issue a warning signal to the user. The logic circuit 26 can be seen in figure 2.

The two functions of the device ("factor" mode and "exposure" mode) would preferably both be used in conjunction by the user of the device. The user would preferably first select factor mode to determine a recommended attenuation factor and then input the same attenuation factor into the device after selecting exposure mode.

The exposure display of the device could take several forms. For instance, LCD display devices could be selected to display the exposure signal generated by the device as a numerical percentage or in the form of a bar chart. A rotary dial display 27 is shown in Figure 3 and a bar display 28 is shown in Figure 4.

The skin pigment selector 50 could have as shown in Figure 5 a dial 29 with a pointer 30 movable in registration with a skin colour bar 31 of varying pigmentation. The rotary dial could be turned by the user, to move between a dark area and a light area, a continuous variation on skin colour being displayed adjacent the dial. A second dial selector 32 is shown in Figure 6 in a housing 33 for the device. The skin tone shading can be seen through a window 34 in the housing 33. A third type of skin pigment selector 35 can be seen in Figure 7 with a pointer 36 movable linearly over a shading scale 37.

In an additional embodiment of the device there would be provided the ability to switch between data for separate users so that several members of a family could simultaneously use the device and select their own output data as required.

In the embodiment described in detail above, the ultraviolet detector 10 is integral with the device.

This need not be the case and the applicant envisages use of a remote detector which could be positioned on a hat worn by the user or the surface of a bag carried by the user or on clothing worn by the user. The remote sensor would be connected by an umbilical to the rest of the device.

Alternatively one portion of the device could be a radio signal transmitter and the other portion a radio receiver. The transmitting portion would at least incorporate the W detector 10 and the receiver portion would at least incorporate the display 19 and sounder 22. The receiver portion would be kept close to the user but the transmitter portion could be located away from the user. Thus the detector could be placed in a direct steady exposure to the W radiation while the user could wear the receiver portion and be free to move about without concern that the UV detector 22 is not in direct exposure to the W radiation. An example of such a receiver/transmitter system is shown schematicaly in Figure 8, with a first half 38 having a radio transmitter 39 and a second half 40 having a radio receiver 41.

In all embodiments the device would preferably be provided with a protective casing or covering which would preferably be proof against water, sand, etc.

The W detector 10 described above could be any type of W detector which generates an electrical signal and could include filter lenses or intensifying lenses.

The device could be provided with a connection to personal stereo headphones such that an alarm signal is given through the headphones.

From the foregoing it will be appreciated that the present invention provides a light monitoring device which can monitor the exposure of a person to ultraviolet radiation and can also recommend an attenuation factor for the barrier means used by the user.

Claims

CLAIMS:

1. Apparatus for use in regulating the exposure of a user's skin to ultraviolet (W) radiation comprising: sensing means operable to generate a signal representative of the intensity of W radiation to which skin is exposed and warning means operable in response to the signal to produce an indication to the user of action to be taken to regulate the exposure of skin appropriate to the sensed intensity.

2. Apparatus as claimed in Claim 1 wherein the warning means comprises: processor means for processing the signal generated by the sensing means to generate a signal corresponding to an attenuation factor of barrier means for protection of the user's skin, and display means for displaying to the user of the device the attenuation factor corresponding to the signal generated by the processor means.

3. Apparatus as claimed in Claim 1 wherein the warning means comprises: processor means for integrating the signal generated by the sensing means over a time period and for generating a signal corresponding to the cumulative sensed W radiation and display means which receives the signal generated by the processor means and displays to the user a display indicative of the cumulative sensed UV radiation.

4. Apparatus as claimed in Claim 3 wherein the processor means can alternatively process the signal generated by the sensing means to generate a signal corresponding to an attenuation factor of barrier means for protection of the user's skin, the display means can alternatively display to the user of the device the attenuation factor of the barrier means corresponding to the signal generated by the processor means, and selection means is provided which is operable by the user to select whether the processor means generates a signal corresponding to the attenuation factor of barrier means or the cumulative sensed W radiation and the display means displays a corresponding output.

5. Apparatus as claimed in Claim 3 or Claim 4 wherein input means is provided which is operable by the user of the device to input to the processor means a signal corresponding to the factor of barrier means used and wherein the processor means varies its output in accordance with the input signal.

6. Apparatus as claimed in any one of claims 3, 4 or 5 wherein the warning means further comprises means for generating an audible noise or a visible signal when the processor means generates a signal corresponding to the cumulative sensed W radiation which is equal to or greater than a preprogrammed maximum cumulative sensed UV radiation.

7. Apparatus as claimed in any one of claims 2 to 6 wherein input means is provided which is operable by the user of the device to select a skin type and wherein the output of processor means varies in accordance with the skin type selected.

8. Apparatus as claimed in any one of claims 2 to 7 wherein the processing means comprises: a voltage controlled oscillator which generates a signal of fixed amplitude and a variable frequency dependent on the voltage of the signal generated by the sensing means, a digital divider for dividing the signal generated by the voltage controlled oscillator, and a digital counter for counting the number of oscillations of the divided signal and generating a signal corresponding to the total number counted.

9. Apparatus as claimed in Claim 2 or Claim 4 wherein the processing means comprises: a voltage controlled oscillator which generates a signal of fixed amplitude and a variable amplitude dependent on the voltage of the signal generated by the sensing means, a digital divider for dividing the signal generated by the voltage controlled oscillated by a programmed constant and a digital counter which counts the number of oscillations of the divided signal in a fixed time period and generates a signal indicative of the number counted.

10. Apparatus as claimed in Claim 5 wherein the processor means comprises; a voltage controlled oscillator which generates signals of fixed amplitude and a variable frequency dependent on the voltage of the signal generated by the ultraviolet sensing means, divider means which divides the signal generated by the voltage controlled oscillator by a fixed constant and by the factor of barrier means as input by the user using the input means, and a digital counter which counts the number of oscillations of the divided signal as a proportion of a preprogrammed constant, generating a signal indicative of the proportion.

11. Apparatus as claimed in Claim 10 wherein a first selector is provided which is operable by the user to select whether the divider divides the signal generated by the voltage controlled oscillator by the factor of barrier means input by the user or by a minumum factor of barrier means.

12. Apparatus as claimed in Claim 10 or Claim 11 wherein a switch is provided which is operable by the user to stop the counter from counting oscillation and to store the number counted in memory, which switch is also operable to restart the counter counting oscillations in addition to the number in memory.

13. Apparatus as claimed in any one of the preceding claims wherein the sensing means of the apparatus includes a radio transmitter for generating a radio signal representative of the intensity of W radiation to which the user's skin is exposed and the warning means comprises a radio receiver for receiving the transmitted signal.

14. Apparatus as claimed in any one of the preceding claims having alarm means for warning the user if the sensing means cease to be exposed to W radiation in use of the device.

15. Apparatus as claimed in any one of the preceding claims wherein the sensing means are remote from the warning means.

16. Apparatus for use in regulating the exposure of a user's skin to ultraviolet radiation substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.