Adjustment of light exposure of the skin

Abstract: Systems for improving the probability for good health and decreasing the risk of cancer and disease comprise: controlling the indoor spectral radiation environment partial body exposure in an amount above 0.6 MED, but not exceeding 0.2 MED per day by irradiating the body with an artificial light source.

Description: The disclosed invention relates to apparatus to adjust the light exposure of the skin. Diet, exercise, sleep, genetics and the environment are factors generally recognized as strongly influencing health. Sunlight as a detrimental environmental factor causing skin cancer and other conditions is often discussed. The beneficial effects of sunlight have had much less attention. For many individuals moderate additions to ultraviolet sunlight exposure as in outdoor work, careful sunbathing, lamp or through a UV-transmitting window exposure can provide systemic benefits. The benefits include: decreased blood pressure, decreased resting heart rate, increased cardiac output, reduced blood cholesterol, increased liver glycogen stores, reduced blood sugar, increased muscular strength and endurance, increased resistance to infections, increased oxygen carrying capacity of the blood, increased adrenaline in tissues, increased stress tolerance, and increased hormones, Kime, 1 . DE-A-31 20 431 discloses a UV-transmitting glazing. It describes how modem medical research has revealed that the metabolic and hormonal balance is controlled by the "energetic proportion" of the optic tract. For this reason, it is necessary to provide the organism with as much natural light as possible. US-A-2,205,353 discloses a window with a cellophane or other transparent flexible material as a sunray member. Either the window is closed and the glass breaks down and excludes the health rays of the sun or the window is open and the sunray member is used which transmits UV lights. US-A-1,343,322 discloses a sash with a set of recesses in a vertical column and a catch permitting positioning of a window in a discrete number of vertically displaced positions. US-A-4,328,853 discloses a folding screen formed by a plurality of successively hinged, rigid, radiation-controlling planar panels supported so the screen can be opened (or extended) and closed (or collapsed). Adjacent panels are supported only at their edges, by a hinge member having symmetrical back-to-back tubular channels. The hinge member possesses sufficient rigidity to permit hinged, side-by-side coaction of the panels from a stacked, generally vertical relationship when the screen is collapsed, to an undulating planar relationship when the screen is opened, which relationship is essential if the screen is to be collapsed without binding. The screen is translatable on a pair of parallel, mono-level tracks, and operated by a flexible drive member extending along a rail and connected to the screen's leading ("lead") panel. A novel skylight including a curb assembly, a "bubble" (or "dome") and a folding screen translatable to-and-fro below the bubble is also disclosed. The curb assembly is mounted on a curb provided on the roof and the assembly includes an access panel which allows access to the folding screen housed in the assembly. The access panel is adjacent the skylight's bubble which is mounted on the walls of the curb assembly. This construction of the curb assembly permits maintenance of the folding screen without disturbing the seal of the bubble on the walls. GB-A-536,127 discloses window shutters comprising inter-connected pintle shuttering operated simultaneously by common means assembled as a unitary structure which may be secured to the existing glazing bars or to roof purlins. The horizontal purlins support glazing bars on which the glazing is mounted. The shutters are formed of corrugated sheet metal panels pivoted on angle rails secured to the bars by clips. Each shutter is provided at the ends with a right-angled bracket and the apices are connected by links. The shutter next the actuating means is braced and connected to the actuating means by a toggle or link to which is pivoted a nut. The nuts for shutters on opposite sides of the actuating means are threaded on a right and left handed screw supported in brackets on spacers on a girder disposed below the actuating gear, the glazing here being replaced by steel sheets. The screw is rotated by a chain gear driven by hand or motor from inside the building. In a modification the angle bars support transverse braced steelwork structures to carry the screw actuating gear. A flexible operating means opening the shutters against the influence of a spring is also described. The proper exposure of skin to solar radiation especially in a changing environment is important to promote health and reduce the risk of disease. An indoor deficiency in ultraviolet B (280 nm to 315 nm) is common. The minimum dose requirement established by the Health Council of the Netherlands, 1986, World Health Organization 85 is 55 MED/year or about 0.15 MED/day. However, multiple exposures over one MED (minimum erythemal dose) greatly increase the risk of skin cancer. Previous devices such as those disclosed in the above-mentioned documents do not provide means to limit the exposure to the desired range and at the same time to enable unrestricted day-lighting and visibility through the window. The purpose of the described embodiments of this invention is to provide apparatus to increase the exposure of the skin when the exposure might be deficient such as during dark winter days and decrease the exposure when the exposure might be excessive such as during bright spring and summer days. The proper exposure of skin to solar radiation especially in a changing environment is important to promote health and reduce the risk of disease. An indoor deficiency in ultraviolet B (280 nm to 315 nm) is common. Excessive dietary vitamin D intake with associated problems results from attempts to compensate for the ultraviolet B exposure deficiency. Methods to increase the indoor ultraviolet B (UV-B) exposure, to avoid a deficiency in exposure and possible vitamin D deficiency while minimizing the risk of over exposure are included. Irregular exposure such as excessive weekend and vacation sunlight exposure for persons working indoors during the week is a common problem. Irregular exposure is prevalent in developed countries and is a factor in the increasing incidence of the possibly fatal melanoma of the skin. Another purpose of this invention is to provide apparatus to obtain a better balance in the day-to-day ultraviolet exposure of the skin. According to the invention there is provided apparatus for controlling ultraviolet transmission to the skin; that is for the exposure of the skin to optical radiation. The embodiments preferably obtain a skin exposure favorable to a good health and avoidance of disease; provide a skin exposure for formation of an appropriate amount of vitamin D to the skin so excessive vitamin D in the diet can be reduced or eliminated; maintain the warmth and comfort in cold environment provided by similar devices without adjustable features; provide a device that is durable, easy to adjust and has a pleasing appearance; provide apparatus to adjust the internal ultraviolet, visible and infrared radiation environment to levels suitable for an individual with particular characteristics; provide apparatus to adjust the inside optical radiation environment for an improved balance through the changing seasons; provide apparatus to keep the skin irradiance low to keep the risk of detrimental effects, including skin cancer, low; and/or provide apparatus to have whole body radiation to reduce the cholesterol in the skin, artery plaque and other tissue. According to the invention, apparatus is provided to have whole body radiation to generate vitamin D at the lowest possible irradiation (to keep the detrimental risk low); and to have whole body radiation over a long time period to allow the body blood pool to circulate through the irradiated skin. According to an aspect of the present invention there is provided a window as specified in claim 1. The window may be a skylight or a vehicle sunroof. The preferred embodiment provides an ultraviolet transmitting window for persons needing additional exposure. This makes it possible to reduce or eliminate the need for dietary vitamin D with potential associated problems. Care in bright season exposure enables the yearly exposure to be reduced even with increases in the dark season exposure. The intake of five servings of fruits and vegetables, low in vitamin D content, each day helps to reduce the intake of the many other foods with high vitamin D content for persons with excess vitamin D intake. The use of a window or skylight in the bathroom enables whole body irradiation without requiring additional time for a person with a busy schedule. The bathroom is the room often kept warm enough for an unclothed person in cold areas far from the equator. The use of an adjustable window or less exposure time allows a reduced exposure during spring and fall seasons when outdoor sunlight exposure and diet provide part of the recommended daily allowance of vitamin D. Exercise clubs, gymnasiums and indoor swimming pools are areas where clothing exposing more skin than usual is worn. These areas offer opportunity for closer to whole body irradiation during the dark seasons. The benefits of exercise are obtained and the exposure is achieved at the same time without requiring additional time for busy persons. Exposure values needed in dark seasons for some persons Since outdoor workers have lower mortality rates than indoor workers, exercise and an increased exposure for indoor workers may improve health. Outdoor workers obtain an exposure of about 10% of the ambient environment while indoor workers obtain about 3% for a weekly average, WHO, 2 . The exposure of office workers could be increased by a factor of about 3.3, along with increased exercise, and an overall improvement in health may be achieved. Overall, there is a need for an appropriate level of skin irradiation for various wavelengths to obtain beneficial effects for health. A deficiency in exposure may occur especially for dark skin persons in cold dark seasons. There is a need to have moderation in the exposure and avoid overexposure especially in hot bright seasons for light skin persons. There is a need for balance in the exposure through the seasons, particularly in the latitudes with large fluctuations in the environment. As there is a need for recommended daily allowances for different diet items without excesses, there is a need for an appropriate daily skin irradiation for different wavelengths without excessive overexposure. Preferably the ranges are 0.02 MED for whole body exposure to 0.2 MED for 10% of whole body exposure for vitamin D generation. Multiple exposures over one MED greatly increase the risk of skin cancer. The minimum dose requirement established by the Health Council of the Netherlands, 1986, World Health Organization, 2, is 55 MED per year or about 0.15 MED per day. This value is slightly less than the above value of 0.2 MED per day value for a person with 10% whole body exposure. Relative to the amount of energy for longer wavelengths favorable for use with the UV-B exposure, one study was conducted for light exposure effects on carbohydrate metabolism. Pincussen, 3, found the relative energy in the ultraviolet and visible regions in sunlight produces favorable maximum ratios of glucose to lactic acid in the blood and maximum ratios of glycogen to lactic acid in the liver and muscle in animal carbohydrate metabolism experiments. By use of the sunlight spectrum the exposure energy for longer wavelengths can be estimated. These exposure values can then be modified as necessary for special purposes and individual requirements. The sufficiency of the combined effects of exposure and dietary vitamin D intake is indicated by the circulating vitamin D in the blood. The measurement of 25-OHD provides a convenient means to verify experimentally the satisfactory functioning of windows and outdoor exposure habits in maintaining recommended vitamin D levels. Garland, 4, recommends a 25-OHD level of 27 to 41 ng/ml to maintain a low risk of colon cancer. For eye protection during indoor exposure it is desired a window be mounted high with low reflecting surfaces to keep the irradiance in the UV blue region low. To irradiate a large fraction of the body it is desired the window be placed at an angle rather than directly overhead. To avoid eye irradiation and irradiate a large fraction of the body a window might be placed upward toward the ceiling relative to a standing position in a shower or in front of a mirror. In bedrooms and hospital rooms, indirect visible lighting with a shaded lamp on the wall irradiating the wall and ceiling over the top of the head of a reclining person is desirable for eye comfort. Since most materials have a low UV-B reflectivity the UV-B irradiation for a reclining person can be directed toward the person from an over-the-head wall location. There are advantages to have vitamin D generation by light exposure rather than obtaining vitamin D from the diet or supplements. In areas not too far from the equator where sufficient sunlight is available year round a bathroom window, other room window, door or skylight with adjustable UV transmission offers a potential lower cost than a lamp requiring electrical power use. A UV transmitting skylight can provide higher room irradiance for indoor sunbathing in cool weather than a window with perpendicular farther in angle from the sun direction when the sun is high in the sky (the time of greatest UV transmission through the atmosphere). The use of a skylight in a bathroom enables whole body irradiation during the periods when clothes do not usually cover most of the skin. Cholesterol Kime, 1 , describes how plaque in arteries is reduced by sun exposure of the skin. First, the cholesterol in the skin is reduced by light exposure converting the cholesterol to vitamin D and other compounds. When the cholesterol in the skin is maintained low for a long period using the light exposure the plaque in the arteries begins to decrease. High blood pressure associated with the plaque decreases as the plaque is removed. To obtain reduced plaque in the arteries and the potential heart disease risk reduction associated with plaque reduction it may be necessary to avoid excessive dietary cholesterol. In experiments with rabbits Altschul, 5, demonstrated serum cholesterol and arteriosclerosis could be reduced by ultraviolet irradiation of the skin. Reduction in exposure in bright seasons In many areas overexposure in bright seasons is a growing problem as indicated by the increasing mortality from melanoma of the skin. Chronic exposure of untanned skin and many sunburns are risk factors for melanoma of the skin. Summer exposure on weekends while being inside the rest of the week and vacations to brighter areas can be associated with increased risk of melanoma of the skin. For a person with sensitive skin the number of MED's in a three hour exposure in midday is as high as 15 at the equator and 10 at 40 degrees latitude, WHO, 2, table 3.3. By staying out of the direct sunlight when the shadow is shorter than the person is tall the protection factor is 2.7 or greater, Holloway, 6. The shadow rule for solar UV-B protection is: sunburn is more likely when shadows are shorter than objects are high. This is a convenient method for reducing the possibility of overexposure and sunburn especially of children in the early summer. For darker seasons when insufficient sunlight is a common problem the midday exposure when the shadows are the shortest are preferred. At high latitudes in darker seasons even the shortest shadow in midday is longer than the person is tall. Balancing the exposure throughout the week and year For indoor workers, a reduction in the weekend and vacation overexposure by clothing style and avoiding the midday bright direct sunlight can help balance the exposure, reduce the exposure and reduce the risk of skin cancer. Tanning booths have the disadvantage they are usually used for high intensity irregular exposures to provide an excessively dark stressful tan with associated skin damage. Frequent moderate exposures with light or no tanning is much less stressful for the skin. Since outdoor workers generally have a lower mortality than indoor workers exercise and light exposure with moderate tanning may be of benefit to many persons. Avoidance of overexposure by high sensitivity individuals For some individuals with increased sensitivity to UV-B radiation the avoidance of excess ultraviolet exposure may be essential. Xeroderma pigmentosum, sarcoidosis, Bell, 7 , and other conditions require special care in controlling any UV-B exposure. Light skin persons living in bright climates have high sensitivity to sunlight relative to those with darker skin better adapted for the local climate. In the U.S. light skin persons living in southern bright climates typically have problems with summer over exposure. Dark skin persons living in the northern darker climate typically have greater problems with winter under exposure. Summary For good health, exposure to a variety of wavelengths is needed, a balance in the exposure from day to day and throughout the year is necessary. Avoidance of overexposure by having moderation in the exposure is essential to prevent skin cancer and other disorders. Excess vitamin D in the diet should be avoided. The diet should be balanced including sufficient fruits, vegetables and antioxidants. A bright environment is desirable for a feeling of well being and avoiding psychological depression. The described embodiments can enhance the probability for good health and reduce the risk of diseases associated with solar radiation exposure and diet for those persons with deficient, excess or non-balanced exposure and diet. A key feature is the use of whole body exposure when possible. This enables the use of very low irradiances for short periods. A slight reduction in the bright season exposure can then more than offset the increased dark season exposure. This results in an overall reduction in the risk of skin cancer. Several techniques are possible to increase the UV-B exposure in cold dark seasons when a deficiency in UV-B exposure is common. Embodiments of the present invention as described by the appended claims are described below, by way of example only, with reference to the accompanying drawings, in which FIG. 1 is an oblique view of an embodiment of the window assembly. FIG. 2 is an enlarged horizontal sectional view taken along line 7-7 of FIG. 1. FIG. 3 is a schematic view of an embodiment of the vehicle sun roof. FIG. 4 is a schematic view of an embodiment of a skylight with adjustable ultraviolet radiation transmission controlled by a motor drive. FIG. 5 is a sectional view taken along line 17-17 of FIG. 4. Adjustable ultraviolet transmission window FIG. 1 is an adjustable window, 11, of known construction which is currently available. The sections are positioned for intermediate ultraviolet transmission. Referring now to the sectional view in FIG. 2 , the outer frame, 12, along with the side supports, 13, are used to support the movable windows 19, 22, and 18. The ultraviolet transmitting window is the outer window, 19. The windows in the middle, 22, and inner, 18, units block the ultraviolet UV-B (280 - 315 nm) radiation. A window insert, 24, is held by a grommet, 27. The window is guided along the track by the guide, 26. The retractable pins, 34, enable the window to be positioned manually using the handles, 31. The pins are held engaged in positioning holes, 43, by the springs, 45, located in holders 40. Referring now to FIG. 1, for maximum ultraviolet transmission, the inner window, 18, is lowered so the outer ultraviolet transmitting window, 19, is unobscured. For maximum blocking of the ultraviolet radiation the inner window, 18, is raised to the top to block the ultraviolet radiation passing through the outer window, 19. For intermediate ultraviolet transmission, the inner window, 18, is positioned at an intermediate position as illustrated in FIG. 1. The UV transmitting window, 19, has an insert, 44, composed of material that is substantially transparent to light rays from the ultraviolet, visible, and part of the infrared solar spectrum. The UV blocking sections, 18, and 22, are substantially transparent to the visible and infrared solar radiation. The side frames, 13, hold the windows and allows them to be positioned for high, intermediate or very low ultraviolet radiation transmission. To raise or lower a window the two positioning pin handles, 31, are moved toward each other by actuator means to release the pins from the positioning holes freeing the window. The window is then moved up or down by actuators and the pins are released when the window is in the desired position. When the pins engage the holes the window is held in place and the actuators can be released. The material of which the ultraviolet transmitting window, 19, insert, 44, is composed is an optically transmitting material such as ultraviolet transmitting glass or plastic similar to the materials described by Driscoll, 8 , and by Sliney, 9 , hereby incorporated into the present application by this reference. Briefly the materials are glasses such as Pyrex , trademark, that transmit a fraction of the ultraviolet B radiation and are not extremely high in cost. Other glasses such as Vycor , trademark and fused silica transmit a higher fraction of the ultraviolet radiation but the cost is prohibitive for many applications. Materials, such as Corex-D and some older types of Plexiglas, trademark, have high transmission in the UV-B. Many of the plastic materials are not solar resistant and darken upon long-term exposure to sunlight and are satisfactory only for low exposure. The material of which the ultraviolet B radiation blocking inserts, 23 and 24, are composed is conventional window glass or plastic. The general UV-B non-direct solar radiation environment in a room is increased when the UV-B transmitting area is increased. In any area with direct solar irradiation through a specularly transparent window the area irradiated by UV-B is increased when the UV-B transmitting area is increased. The direct irradiation is not altered. The risk of overexposure is reduced by use of a diffusely UV-B transmitting window 19, insert, 44, of the preferred embodiment. A meter can be used to measure the ultraviolet solar radiation transmitted by the window. Estimates of the appropriate exposure for a person with particular skin type is needed to determine the exposure time for window transmitted or lamp generated ultraviolet B radiation. Adjustable ultraviolet transmission sunroof FIG. 3 is an adjustable ultraviolet transmission sunroof, 65, for a vehicle, 60. The outer element, 62, is ultraviolet diffusely transmitting material. The inner sliding element, 64, blocks the ultraviolet radiation and attenuates the visible light. By positioning the inner sliding element, 64, the ultraviolet transmission can be adjusted. The method of operation is similar to the window in FIG. 1. The inner section, 64, is partially transparent to visible light to avoid glaringly bright light transmission when the sun is overhead. A person receiving too little or too much ultraviolet B radiation can adjust the sunroof, 65, for appropriate UV-B transmission. A person receiving sufficient UV-B radiation while outside the vehicle can position the sliding element, 64, to block the ultraviolet B radiation. Skylight with adjustable ultraviolet radiation transmission Fig. 4 is a skylight, 100, having body portion, 109, and lead screw, 102, for positioning of the UV-B blocking element, 101. A stationary UV-B blocking element, 104, is located at one end of the skylight. FIG. 5 is a sectional view along line 17-17 in FIG. 4 . A rider, 105, on the lead screw, 102, is attached to the movable UV-B blocking element, 101. The stationary blocking element, 104, is located near and parallel to the movable element, 101, as shown in FIG. 5. The drive motor, 103, can be remotely controlled to position the movable element to increase or decrease the area transmitting UV-B radiation. The outer element, 108, diffusely transmits ultraviolet, visible and part of the infrared solar radiation. The outer element also serves as a weather shield for rain, snow, sleet and wind. References: 1. Kime, Z. R.: "Sunlight"; World Health Publications, Penryn, CA. (1980). 2. World Health Organization (WHO). Environmental Health Criteria 160, Ultraviolet Radiation. Geneva 1994. 3. Pincussen, L.: Effect of ultraviolet and visible rays on carbohydrate metabolism. Arch. Phys. Therapy, X-ray, Radium 18:750-755;1937. 4. Garland, Cedric F., Frank C. Garland et al.: Colon cancer parallels rickets, pages 81-111 in: Calcium, Vitamin D and Prevention of Colon Cancer 1990. Edited by M. Lipkin, H. L. Newmark and G. Kelloff. CRC Press, Boco Raton, Fla. 5. Altschul, M. U.: Inhibition of experimental cholesterol arteriosclerosis by ultraviolet irradiation. NEJM: 249:96-99;1953. 6. Holloway, L.: Atmospheric sun protection factor on clear days: It's observed dependence on solar zenith angle and its relevance to the shadow rule for sun protection. Photochem. and Photobio. 56:229-234;1992. 7. Bell, N. H.: Endocrine complications of sarcoidosis. Endrocrinol. Metab. Clin. North Am. 20: 645-654; 1991. 8. Driscoll, W. G., Editor: Handbook of Optics, Optical Society of America, McGraw Hill Company, New York, 1978. pages 7-24 and 8-32. 9. Sliney, D. and Wolbarsht, M: Safety with Lasers and Other Optical Sources. Plenum Press, New York, 1980. page 495.

Claims: A window (11, 100, 65) including adjustable light transmitting sections (18, 19, 22, 108, 101, 62, 64) to control a spectral radiation environment interior to said window, at least one first section (19, 108, 62) for high ultraviolet transmission including transmission of ultraviolet B radiation; at least one second section (18, 22, 101, 64) for transmission of visible and infrared light while substantially blocking ultraviolet B radiation; frame means (12, 109) operable to hold said first and second sections in place and means (31, 102) for positioning said sections relative to each other. A window according to claim 1, comprising a third section (18, 22) with differing spectral transmission from said first section (19); and means (31) for moving said third section relative to said first and second sections. A window according to claim 1 or 2, including blinds to further control the light transmission through the sections. A window according to claim 1, 2 or 3, wherein the ultraviolet transmitting section is composed of a material selected from glass or plastic material. A window according to any preceding claim, wherein the means for moving said first section relative to said second section includes retractable pins (34). A window according to claim 5 wherein at least one handle (31) is provided to move said retractable pins. A window according to claim 1, wherein said window is a skylight (100), said skylight further including means on said frame means (109) for mounting said skylight to a support; and wherein said second section (101) is movable between a position substantially entirely blocking said first section and a position allowing said first section to transmit substantially all radiation. A window according to claim 7 wherein the means for moving said second section comprises a lead screw (102). A window according to claim 8, wherein said lead screw includes a rider (105) which is connected to said second section and enables said second section to be movable relative to said skylight and said first section (108). A window according to claim 1, wherein said window is a vehicle sunroof (65). A window according to claim 10, wherein the first section (62) is made of a material selected from glass and plastic materials and wherein the second (64) section is made of a material selected from glass and plastic materials. A window according to any preceding claim, wherein the ultraviolet transmitting section is the outermost section.

Inventors: CHUBB CHARLES R, ROTTLER LISA C, CHUBB, CHARLES R., ROTTLER, LISA C.
Applicants: CHUBB CHARLES R, ROTTLER LISA C, CHUBB, CHARLES R., ROTTLER, LISA C.
Application year: 1999
Main classification: E06B9
IPC codes: A41D7, A41D1, A61N5, A41D13