The GOLF DISC AND FLYING DISC AND MULTIPURPOSE PICK UP TOOL is a lightweight, collapsible, segmented shaft fitted with a durable suction cup. The suction cup provides a vacuum adhesion on either side, or any location, on the golf disc or flying disc or other generally flat and smooth objects. The disc or object can then be picked up (retrieved) from any surface or obstacle within reach. A flick of the finger to the suction cup edge breaks the vacuum and the tool and disc or object are separated. The tool can be deployed and used with one hand. The tool can be carried and used as extended or folded and stowed.

Disc golf is played and scored just as a game of regular "ball" golf. Instead of balls, plastic flying discs are used. Golf discs are smaller and heavier than the common "Frisbee" type disc. There are pole mounted, elevated metal baskets for "holes" and common Tee-Off pads from which to throw a disc. The game is scored just as regular golf: A player is given a designated number of throws to score "even", also known as "par". A player may throw any number of times, depending on course, weather conditions and skill. Thrown (played) golf discs can land anywhere one can imagine: flat on the ground, in weeds, in water, in bushes or trees, in crevices, or under logs.
Need for this Tool:
In a typical single game of 18 hole, par 3 per "hole" disc golf, one can expect to bend or squat down and pick up a disc at least 54 times, if one is lucky to make "even" par. A typical golf game can require a thrower to pick up discs 100s of times. A typical practice session can also cause a player to throw and pick up discs 100s of times. My invention eliminates squatting, bending, reaching, or stooping for ones' discs or other objects. This tool is deployed and readied with one hand, in one motion, and retrieves the disc quickly and securely. It is a time saver and a back saver. Other generally flat and smooth objects and items such as playing cards, poker chips, or cell phones are similarly easily retrieved.
FIG. 1:
Item 1 is the suction cup
Item 2 is the cotter pin
Item 3 is the metal tubing coupling sleeve
Item 4 is the fiberglass segment
Item 5 is the "Shock Cord" (stretch cord)
Item 6 is a knot tied in the cord
Item 7 is a plastic cap
Item 8 shows the staking positions on item 3
FIG. 2:
Items 1, 2, 3, 4,7 and 8 as visible in a finished, unfolded, deployed tool.
Technical Design Description (Specification):
GOLF DISC AND FLYING DISC AND MULTIPURPOSE PICK UP TOOL is a multi-segmented, collapsible, hollow fiberglass shaft, (thick-walled tubing), fitted with a suction cup at the distal end. The segments (Item 4) are fiberglass tubing ⅜ inches in diameter with an ⅛ diameter through-hole and each segment is 11 inches total length. All three segments have a two inch long metal tubing coupling sleeve (Item 3) attached to one end by friction, glue and punch staked (Item 8). The sleeve is attached one inch from end on the segment. The coupling sleeves have sufficient inside diameter to loosely receive the next segment. The distal segment coupling sleeve serves as the fixation point of the suction cup. All exposed fiberglass ends are beveled and sanded for fit and finish. The segments have a measured length of stretch cord (shock cord) (Item 5) running through the center and tied (Item 6) at either end with sufficient pre-stretch as to allow the deployed tool segments to fit snug enough to pick up a disc without disjoining, but loose enough to allow pulling apart the segments for folding (stowing). The proximal segment has a plastic cap (Item 7) slid over the end to dress the tool and protect the stretch cord knot. The distal end of the tool has a one inch diameter durable plastic suction cup (Item 1) slid in and pinned horizontally to the bottom coupling. The pin (Item 2) attaches through two holes drilled directly across from one another. Other diameter suction cups can be attached in the same manner. Note: Segments can be made of fiberglass, aluminum, or other plastics or metals. I chose fiberglass because of lightness, strength, and durability.
How I Made it:
Cut three like sizes of measured fiberglass tubing. These lengths of fiberglass tubing are now the "segments" (Item 4). Cut three like sizes of metal tubing. These lengths of metal tubing sleeves are now the "couplings" (Item 3). The couplings will have an inside diameter sufficient as to allow a tight fit on the outside ends of the segments during assembly.
Secure a segment and glue and force fit a length of coupling to one end. Slide the ends together for half the distance of the coupling. Assemble two more identical segments. Secure each segment in a suitable vise holding the segment on the coupling end. Stake punch the segment couplings once in the center equidistant from the ends to trap the glued sections together (Item 8).
Secure one segment. This segment will be the "distal" segment. Locate coupling end. Clamp coupling. Using a machine drill, drill two holes in a sufficient perpendicular location horizontally so as to slide a small cotter pin through the coupling. Locate the holes in sufficient location so as to be in the center of the protruding mounting stub on the suction cup. These three assembled segments are now the "finished segments". Slide the finished segments together, male-female order. These finished segments are now the tool, without the suction cup. The tool, as positioned properly, will have a coupling at the distal end and a finished fiberglass end at the proximal end.
Secure a length of shock cord (Item 5) sufficient to pass through the tool with enough excess length needed to tie a simple overhand knot (Item 6). Slide the shock cord all the way through the joints.
The shock cord end shall be flame heated on the ends to dress the cord, prohibit fraying, and facilitate easy insertion through the segments. On the non-drilled (proximal) end, tie a common overhand knot. On the distal end, grasp the shock cord and pull so as to cause a pre-tensioned state of the cord. Place a common clothespin at the coupling to hold the tensioned cord so as to make tying off the cord easier. Tie a simple overhand knot, cut the excess, and dress the frayed end as described above. Allow the cord to contract and pre-tension the tool. Locate the distal end. Secure a suction cup (Item 1). Pre-drill a hole of sufficient size as to allow a small cotter pin (Item 2) to pass through. Drill the hole horizontally in the center of the suction cup stub. Slide the pre-drilled stub end into the pre-drilled coupling. Slide a sufficient size cotter pin through the coupling and suction cup. To finish and secure the cup assembly, bend the cotter pin ends accordingly. Friction fit a small plastic cap (Item 7) on the proximal end to dress and protect the shock cord knot and provide comfort to the user. The finished tool is painted, covered, or adorned for durability and aesthetics.
Tool Deployment Procedure (How To Use):
Secure a tool in the folded (stowed) position. With either hand, grasp the proximal (non-suction cup end) of the pick up tool. While holding the top section, simply allow the remaining segments to gravitate down and snap automatically and positively in place. Locate the disc or object to pick up. The suction cup end of the tool is then pressed against either side of the disc, back or front, as landed in play. Positive and tight suction is quickly and easily attained. The disc is "locked" and the disc may be raised for storage or further play. The tool can be "stuck" to any area of the disc. Middle placement is not required. For instance, if only a small edge of the disc protrudes from under a log, the tool can lock on to just enough disc to allow the suction cup to press in. This entire operation can be done one-handed and takes seconds. A quick flick of a finger to the edge of the suction cup breaks the suction seal and the disc comes free from the tool. The tool can be folded back up and stowed or carried fully extended (deployed).
Design Uniqueness:
My design is vastly different than any other design for the following reasons: Tool can be fully extended and locked with one hand, using one motion. Other designs make use of both hands for extension and "lock" of the folding tubular sections and then both hands are needed for screwing on various attachments. This tool design uses a small, strong, and durable suction cup device which attaches to, and locks on the disc utilizing a vacuum. This action enables the person retrieving the disc to lift the disc to a position to easily grasp the disc. Other designs such as a hook of any type can only drag the disc and one still has to bend, reach or grasp in some other way, the retrieved disc.
A typical golf "disc" is a solid, smooth plastic and typically lands flat when thrown. A disc golf disc is unlike a traditional "Frisbee" flying disc because the disc golf disc is smaller, heavier, and flatter. There are no holes, ledges or other areas in which a hook can be placed for positive retrieval. Any "hook" type retriever can only drag the disc. This dragging and hooking action will certainly scratch, gouge and mar the disc. My design positively and securely grabs the disc, and will not come free until removed by the disc golfer. Disc can be retrieved and removed from the suction device all with the same hand. This device really picks up the disc and gets it back into the golfers hand. It doesn't merely hook the disc and require the player to carefully drag or suspend the disc so it can be quickly grabbed before it can again fall to the ground.
My design enables a disc golfer, for instance, to retrieve a disc from under the water or above in a tree without the disc being merely hooked and moved to another location and perhaps falling back into the water or out of the tree onto the ground. My design eliminates this fatal design flaw in that the disc remains securely locked onto the tool until the disc golfer physically disengages the suction cup by simply breaking the suction with a finger or finger nail.
My design will enable a physically challenged player to retrieve a disc off any surface without any bending at all. This action is accomplished in one motion: pointing the tool (device) at the disc, lowering the device to either the front or back of the disc and gently pushing the suction cup onto the disc. Then, the disc is brought to any level or position to facilitate removal for storage or throwing. One need not bend, stoop, or squat.
My design is truly a one-handed tool, and those golfers (players) confined to a wheelchair or are otherwise disabled can play disc golf and retrieve their own discs quickly and easily. With the tool in the stowed (folded) position, simply holding the top section and flicking the hand downward "sets" the device for use. This design of loose fitting tubular section ends and a tight length of shock cord enables the tool to be quickly flicked and extended with one hand, in one motion. This design uses lightweight fiberglass tubes with steel sleeves pressed and glued between them for a positive slip fit.
Other designs require a machining of tubes to have an end fit into another end without the sleeve and is impractical to build because this type of section-connective joint would have to start with a solid fiberglass rod and be drilled and machined to male and female ends accordingly. The other designs only use a metal "hook" type mechanism which must be screwed onto the end of the tool. This action itself takes two hands and adds a step for tool setup and use. Then, the hook must be carefully positioned under the disc and the player must be balanced, steady and lucky enough to pick up the disc. Another design uses a heavy and cumbersome clamping mechanism and is not practical or useful.
My design has a suction cup semi-permanently attached by way of friction and a small, horizontal cotter pin, or clip, or alternately, friction mounted utilizing a small stub. The cup itself can bend and wobble, allowing retrieval of discs at extreme angles. Cups can be user-substituted or changed after normal wear causes degradation of suction. This design is 33 inches in length consisting of 3 sections of 11 inches. This overall length is the average length of a walking cane. This size, as collapsed, allows the device to be carried in a pocket, a pouch, or zipped inside the golf bag. This is a proven design and two identical models have been made and field tested under all weather and disc golfing conditions.

Golf disc and flying disc and multipurpose pick up tool


The present invention is directed to the use of compounds of Formula (I), as active principals for treating skin conditions and compositions containing these compounds

1. Field of Invention
The present invention relates to a new class of compounds for use as active principals for topical treatment of skin conditions, to compositions containing these compounds and to methods of treating skin conditions using these compounds and compositions. Compounds of the class include those of Formula (I):
wherein, R4 is (CR5R6-CR7R8-X1)n-CR9R10R11; n is an integer from 1 to 18; R1, R2, R3, R5, R6, R7, R8, R9, R10 and R11, are independently hydrogen or non-hydrogen substituents, with preferred non-hydrogen substituents including alkyls, alkenyls, oxa-alkyls, aralkyls and aryls; and X, X1, Y and Z are independently, 0, NH or S, with preferred compounds including those in which X, X1, Y and Z are each oxygen and R1, R2, R3, R5, R6, R7, R8, R9, R10 and R11 are each hydrogen.
2. Description of the Prior Art
Dermal use of alpha hydroxyacids having an all carbon backbone is described in U.S. Pat. No. 5,091,171. Cosmetic compositions using 2-hydroxyalkenoic acid are disclosed, for example, in U.S. Pat. No. 5,108,751. Such compounds must have an unsubstituted alpha hydoxy group on a carbon backbone and are purportedly used to impart beneficial effects to the skin. However, the trend is away from the use of such alpha hydroxyacids since they necessitate low operational pH ranges that for the most common forms, i.e. glycolic and lactic acids, are known to cause skin irritations.
Topical formulations comprising straight, all carbon backbone, dicarboxylic acids have been proposed as replacements for alpha hydroxyacids. For example, U.S. Pat. Nos. 4,292,326, 4,386,104 and 5,385,943 describe the use of dicarboxylic acids having 7 to 13 carbon atoms for various skin indications. Similarly, U.S. Pat. No. 4,885,282 states that a 4 to 18 carbon dicarboxylic acid compound is useful for the treatment of skin disorders.
The problem with the use of these dicarboxylic acids is their inherent insolubility in aqueous solutions. Such solutions make up the majority of cosmetic delivery systems. Also, dicarboxylic acids that have all carbon backbones are solid at ambient temperatures, extremely difficult to work with and, if a solution is achieved, the result is an aesthetically unpleasant mixture unsuitable for cosmetic use.
Therefore, there is a need for a compound or class of compounds that can be used as mild, exfoliating actives for topical treatment of skin.
There is also a need for a mild, exfoliating topical composition that contains a water soluble compound that can be manufactured into an aesthetically acceptable cosmetic or dermatologic products.
It is an object of the present invention to provide a water soluble compound or class of such compounds that can be manufactured into an aesthetically acceptable, mild, exfoliating composition for topical use.
It is another object of the present invention to provide topical compositions with such water soluble compounds that have multiple skin care benefits.
It is a further object of the present invention to provide a new, dermatologic and cosmetic use for oxa acids.
These and other objects will become evident from the following disclosure.
The basic compound of this invention is a compound of the following Formula (I):
wherein, R4 is (CR5R6-CR7R8-X1)n-CR9R10R11; n is an integer from 1 to 18; R1, R2, R3, R5, R6, R7, R8, R9, R10 and R11, are independently hydrogen or non-hydrogen substituents.
X, X1, Y and Z are independently, 0, NH, or S. Preferred are those compounds in which X, X1, Y and Z are all oxygen. Most preferred are those compounds in which X, X1, Y and Z are each oxygen, and R1, R2, R3, R5, R6, R7, R8, R9, R10 and R11, are each hydrogen.
The preferred non-hydrogen substituents include alkyls alkenyls, oxa-alkyls, aralkyls and aryls. Examples of non-hydrogen substituents include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, heptyl, octyl, nonyl, dodecanyl, methoxy, ethoxy, propoxy, butoxy, cyclohexenyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, cyclobutyl and cyclohexanyl.
Exemplary compounds of Formula (I) include 3,6-dioxaheptanioic acid (CH3-0-CH2-CH2-0-CH2-COOH); 7,7-dimethyl-3,6-dioxaheptanoic acid ((CH3)2CH-0-CH2-CH2-0-CH2-COOH); 3,6-dioxaheptanoic acid ethyl ester (CH3-0-CH2-CH2-0-CH2-COOC2H5); 3,6-dioxaheptanoic acid amine (CH3-0-CH2-CH2-0-CH2-CONH2); 3,6-dioxaheptanoic acid dodecyl ester (CH3-0-CH2-CH2-0-CH2-COOC12H25); 2-phenyl-3,6-dioxaheptanoic acid (CH3-0-CH2-CH2-0-CH(Phe)-COOH); 2-benzyl-3,6-dioxaheptanoic acid (CH3-0-CH2-CH2-0-CH(CH2Phe)-COOH); 2-methyl-3,6-dioxaheptanoic acid (CH3-O-CH2-CH2-O-CH(CH3)-COOH); 3-amino-6-oxaheptanoic acid (CH3-O-CH2-CH2-NH-CH2-COOH); 3,6,9-trioxadecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 2-phenyl-3,6,9-trioxadecanoic acid (CH2-O-CH2-CH2-O-CH2-CH2-O-CH(Phe)-COOH); 2-benzyl-3,6,9-trioxadecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH(CH2-Phe)-COOH); 2-decyl-3,6,9-trioxadecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH (C10H21)-COOH); 3,6,9,12-tetraoxatridecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 3,6,9,12,15-pentaoxahexadecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 2-methyl-3,6,9-trioxadecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-CH(CH3) -COOH) ; 10,10-dimethyl-3,6,9-trioxadecanoic acid ((CH3)2CH-O-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 2-ethyl-3, 6,9,12-tetraoxatridecanoic acid (CH3-O-CH2-CH2-O-CH2-CH2-O-C2-CH2-O-CH(C2H5)-COOH); 10-phenyl-3,6,9-trioxadecanoic acid (Phe-CH2-O-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 3,6,9-trioxadecanoic acid ethyl ester (CH3-O-CH2-CH2-O-CH2-CH2-O-CH2-COOC2H5); 3,6,9-triaminodecanoic acid (CH3-NH-CH2-CH2-NH-CH2-CH2-NH-CH2-COOH); 3,6,9,12-tetraaminotridecanoic acid (CH3-NH-CH2-CH2-NH-CH2-CH2-NH-CH2-CH2-NH-CH2-COOH); 9-amino-3,6-dioxadecanoic acid (CH3-NH-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 6,9-diamino-3-oxadecanoic acid (CH3-NH-CH2-CH2-NH-CH2-CH2-O-CH2-COOH); 3,6,9-trithiodecanoic acid (CH3-S-CH2-CH2-S-CH2-CH2-S-CH2-COOH); 9,12-dithio-3,6-dioxatridecanoic acid (CH3-S-CH2-CH2-S-CH2-CH2-O-CH2-CH2-O-CH2-COOH); 9-amino-3,6-dioxadecanoic acid monoamide (CH3-NH-CH2-CH2-O-CH2-CH2-O-CH2-CONH2); 3,6,9-trioxadecanoic acid monoamide (CH3-O-CH2-CH2-O-CH2-CH2-O-CH2-CONH2); 10,10-dimethyl-3,6,9-trioxadecanoic acid amide (CH3)2CH-O-CH2-CH2-O-CH2-CH2-O-CH2-CONH2); 10,10-dimethyl-3,6,9-trioxadecanoic acid ethyl ester ((CH3)2CH-O-CH2-CH2-O-CH2-CH2-O-CH2-COOC2H5); 10,10-dimethyl-3,6,9-trioxadecanoic acid heptadecanyl ester ((CH3)2CH-O-CH2-CH2-O-CH2-CH2-O-CH2-COOC17H35) ; and 10,10-dimethyl-3,6,9-trioxadecanoic acid ((CH3)2CH-O-CH2-CH2-O-CH2-CH2-O-CH(CH3)-COOH)
Compounds of Formula (I) are described as intermediates useful in the making of curing agents and hardeners for epoxy resins in U.S. Pat. Nos. 5,017,675 and 5,319,004, both assigned to Hoechst AG. German Published Application No. DE-A-2936123 describes the preparation of such epoxy resin intermediate compounds. Such compounds are also commercially available from Hoechst AG.
Compounds of Formula I can also be prepared from commercially available polamines, polyols and polythiols by routine chemical reactions well known to those skilled in the art such as amidation, catalytic oxidation, esterification and other well known organic chemistry synthetic protocols, as described in organic chemistry textbooks including March, Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 3rd ed., John Wiley Interscience (1985) and Carey et al. Advanced Organic Chemistry, 3rd ed., Parts A and B, Plenum Press, New York (1990).
The oxa acid compounds useful in the topical compositions of this invention can also be in the form of derivatives that are converted back to an acidic form by action of hydrolytic enzymes in the skin such as glycosidases, phosphatases, esterases and amidases. Examples of suitable derivatives include esters of Formula I compounds with aliphatic alcohols, carbohydrates, amides, lactones and anhydrides
As defined herein, all compounds of Formula (I), and derivatives thereof, will be referred to collectively as xe2x80x9coxa acidsxe2x80x9d and/or xe2x80x9coxa compoundsxe2x80x9d and/or xe2x80x9coxa acid compoundsxe2x80x9d.
A xe2x80x9ctopical applicationxe2x80x9d refers to spreading or laying directly onto the surface of skin. A xe2x80x9ctopical compositionxe2x80x9d refers to a composition intended to be directly layed onto or spread on the surface of skin. An xe2x80x9ceffective amountxe2x80x9d means an amount of a compound or a composition sufficient to induce a positive change (e.g. normalization of desquamation) in the skin condition to be treated such as those attributed to, accompanied or exacerbated by abnormal desquamation. A xe2x80x9cphysiologically acceptable vehiclexe2x80x9d or a xe2x80x9csuitable topical vehiclexe2x80x9d refers to drugs, cosmetics, medicaments or inert ingredients that are suitable for use in direct contact with human tissues without undue toxicity. All percentages refer to weight percent based on the total weight of the topical composition.
In accordance with the invention, oxa compounds are used as active principals in topical applications to treat various skin conditions attributed to, accompanied by or exacerbated by abnormal desquamation. Such conditions include, but are not limited to, dry skin, ichthyosis, palmar and plantar hyperkeratoses, dandruff, lichen simplex chronicus, Dariers disease, keratoses, lentigines, age spots, melasmas, blemished skin, acne, psoriasis, eczema, pruritis, inflammatory dermatoses, striae distensae (i.e. stretch marks), warts and calluses.
The compounds are unexpectedly and surprisingly found to be useful as active agents in topical preparations for treating signs of dermatological aging, both photoaging and intrinsic aging, including skin wrinkles such as fine wrinkling in the eye area or xe2x80x9ccrows feetxe2x80x9d or fine wrinkles around the mouth area, irregular pigmentation, sallowness, loss of skin resilience and elasticity.
Oxa compounds and topical compositions containing them are also useful for treating disorders associated with the nails, cuticles and hair such as ingrown hair, folliculitis and Pseudofolliculitis barbae. The present compounds also soften hair and promote the elimination of hair ingrowths, making the compounds of Formula (I) useful in shaving compositions.
The oxa compounds can be incorporated into the compositions as free acids or as corresponding salts derived by neutralization with organic or inorganic bases, such as triethanolamine, arginine, lysine, potassium hydroxide, sodium hydroxide, lithium hydroxide and ammonium hydroxide.
When used in combination with a physiologically acceptable vehicle to form a topical composition, the effective amount of the oxa acid compound can be within the range from about 0.1% to about 95%. Both the effective amount and the frequency of application will vary within this range based on the particular skin condition treated, the age and physical condition of the person under treatment, the severity of the condition, the duration of treatment, the nature of concurrent treatments, the specific compound or compositions employed, the particular vehicle utilized to deliver the compound or compositions, and other like factors within the knowledge and expertise of those skilled in the art.
The efficacy of the oxa acid compounds in treating skin conditions has been found to be affected by the pH of the composition. Thus, it is believed desirable to maintain the pH of the composition in the acid range pH  less than 7.0, preferably pH less than 5.0, most preferably in the pH range between 3.5 and 4.0. The pH of the composition can be adjusted by adding water soluble salts formed by strong bases (e.g. KOH, NaOH, NHOH) and weak acids (e.g. phosphoric acid, acetic acid, lactic acid, carbonic acid). Examples of such salts include potassium biphosphate, sodium phosphate, sodium acetate, sodium lactate and the like. Other methods useful for adjusting the pH of topical compositions are known to those skilled in the art.
Compositions of the present invention have clear advantages over alpha hydroxyacid formulations, including superior mildness. Formulations containing alpha hydroxyacids, such as glycolic and lactic acids, can cause substantial discomfort to some individuals and symptoms of severe skin irritation in others, upon facial application. While being significantly gentler to skin than glycolic acid formulations, the oxa acid compositions of the present invention are highly effective in normalizing the desquamation of the upper stratum corneum. Such normalization is required to alleviate the skin conditions listed above.
The topical compositions of the present invention also have advantages over compositions containing dicarboxylic acids including better water solubility and superior stratum corneum desquamatory activity. Oxa acids easily dissolve in water to concentrations of at least 20 to 30% by weight. Therefore, oxa acids have now been found to allow a much wider range of composition flexibility. Dicarboxylic acids of moderate to long chain length, which have straight, all-carbon backbones, are virtually insoluble in water and other aesthetically acceptable vehicles. This severely limits the choice of delivery vehicles for the dicarboxylic acids. The desquamatory activity of such dicarboxylic acids is also questionable. For example, tests have demonstrated that formulations containing 5% and 10% dodecanedioic acid do not produce any normalizing effect on stratum corneum desquamation beyond that of its vehicle alone.
Some specific examples of vehicles found to be suitable for use with the oxa acids include:
(1)(a) about 2 wt. % to about 10 wt. % glycerin, (b) about 1 wt. % to about 10 wt. % propylene glycol, (c) about 0.1 wt. % to about 2 wt. % hydroxyethyl cellulose, (d) about 0.1 wt. % to about 1 wt. % imidazolidilyl urea, and (e) about 0.01 wt. % to about 2 wt. % disodium-EDTA;
(2)(a) about 1 wt. % to about 10 wt. % glycerin, (b) about 1 wt. % to about 10 wt. % propylene glycol, (c) about 1 wt. % to about 10 wt. % octyl palmitate, (d) about 1 wt. % to about 10 wt. % myristyl myristate,(e) about 1 wt. % to about 6 wt. % cetearyl alcohol/Ceteareth-20, (f) about 0.5 wt. % to about 6 wt. % glyceryl monostearate, (g) about 0.1 wt. % to about 2 wt. % hydroxyethyl cellulose, (h) about 0.1 wt. % to about 1 wt. % imidazolidilyl urea, (i) about 0.05 wt. % to about 0.5 wt. % methyl paraben, and (j) about 0.01 wt. % to about 2 wt. % disodium-EDTA; and
(3)(a) about 2 wt. % to about 10 wt. % glycerin, (b) about 1 wt. % to about 10 wt. % octyl palmitate, (c) about 1 wt. % to about 10 wt. % myristyl myristate, (d) about 1 wt. % to about 7 wt. % cetearyl alcohol/Ceteareth-20, (e) about 1 wt. % to about 10 wt. % propylene glycol, (f) about 1 wt. % to about 6 wt. % glyceryl monostearate, (g) about 0.1 wt. % to about 2 wt. % hydroxyethyl cellulose, (h) about 0.1 wt. % to about 1 wt. % imidazolidilyl urea, (i) about 0.05 wt. % to about 0.5 wt. % methyl paraben, and (j) about 0.01 wt. % to about 2 wt. % disodium-EDTA.
The topical compositions of the present invention can be made as lotions. A first or more basic lotion comprises: about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid; and, the remainder water. A second lotion has about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid; about 0.5 wt. % to about 50 wt. % of an emollient; about 0.1 wt. % to about 30 wt. % of an emulsifier; and, the remainder water. The second lotion may also contain up to about 10 wt. % of a preservative; from about 0.1 wt. % to about 3 wt. % of a fragrance; and up to about 5 wt. % of a dye or a pigment.
The topical composition of the invention can also be formulated as a cream. A first or more basic cream comprises about 0.1 wt. % to about 95 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid; from about 0.5 wt. % to about 50 wt. % of an emollient; about 0.1 wt. % to about 6 wt. % of a thickener; and, the remainder water. A second, preferred cream comprises about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid; from about 0.5 wt. % to about 50 wt. % of an emollient; about 0.1 wt. % to about 30 wt. % of an emulsifier; about 0.1 wt. % to about 6 wt. % of a thickener; and, the remainder water.
The oxa acid can be combined with most conventional emollients including mineral oil, petrolatum, paraffin, ceresin, ozokerite, microcrystraline wax, perhydrosqualene dimethyl polysiloxanes, methylphenyl polysiloxanes, silicone-glycol copolymers, triglyceride esters, acetylated monoglycerides, ethoxylated glycerides, alkyl esters of fatty acids, fatty acids and alcohols, lanolin and lanolin derivatives, polyhydric alcohol esters, sterols, beeswax derivatives, polyhydric alcohols and polyethers, and amides of fatty acids. Other suitable emollients can be found in Sagarin, Cosmetics, Science and Technology, 2nd Ed., vol. 1, pp. 32-43 (1972), the contents of which are incorporated herein by reference.
The emulsifiers that can be cationic, anionic, nonionic, amphoteric, or a combination thereof. Nonionic emulsifiers are preferred. Exemplary nonionic emulsifiers are commercially available sorbitans, alkoxylated fatty alcohols and alkyl polyglycosides. Anionic emulsifiers may include soaps, alkyl sulfates, monoalkyl and dialkyl phosphates, alkyl sulphonates and acyl isothionates. Other suitable emulsifiers can be found in McCutcheon, Detergents and Emulsifiers, North American Edition, pp. 317-324 (1986), the contents of which are incorporated herein by reference.
The preservatives suitable for use with the present compositions include alkanols, especially ethanol and benzyl alcohol, parabens, sorbates, urea derivatves, and isothiazolinones.
While such lotions or creams can be made using conventional homogenization methods known to those skilled in the art, it is also possible to use a process of microfluidization that involves co-mixing the aqueous phase and the oil phase of such creams and lotions in a high-pressure homogenizer that reduces the emulsion particle size dramatically to about {fraction (1/400)}th the size of those in creams and lotions prepared without applying high pressure. Microfluidization allows one to prepare elegant stable creams and lotions containing effective amounts of an oxa acid without the use of traditional emulsifiers and surfactants.
The topical compositions of the invention can also be formulated as a micro-emulsion. A first, basic micro-emulsion system comprises about 0.1 wt. % to about 50 wt., preferably from about 1 wt. % to about 30 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid; from about 0.5 wt. % to about 20 wt. % of a hydrocarbon; from about 0.5 wt. % to about 20 wt. % of an oil; and, the remainder water. A second, more preferred micro-emulsion system comprises about 1 wt. % to about 20 wt. % of the oxa acid; from about 0.5 wt. % to about 15 wt. % of a hydrocarbon; from about 1 wt. % to about 15 wt. % of an oil; from about 0.1 wt. % to about 10 wt. % of a fatty alcohol; up to 30 wt. % of a nonionic surfactant; and, the remainder water.
The topical compositions of the present invention can be formulated as oil-in-water or water-in-oil emulsions, gels, lotions, ointments, sticks, sprays, tapes, patches. The inventive compositions can also be in the form of a multiphase emulsion, such as a water-in-oil-in-water type emulsion as disclosed in U.S. Pat. No. 4,254,105, incorporated herein by reference. The compositions of the present invention can also be formulated as triple emulsions of the oil-in-water-silicone fluid type disclosed in U.S. Pat. No. 4,960,764, incorporated herein by reference.
The compositions of the invention can also be made as a liposomal formulation, for example, according to the methods described in Mezei, J. Pharmaceut. Pharmacol., vol. 34, pp. 473-474 (1982), or modification thereof. In such compositions, droplets of the oxa acid solution can be entrapped inside the liposomal vesicles with the shell of the liposome being a phospholipid or other suitable lipids (e.g. skin lipids). To form a topical composition, the liposomes can then be added to any carrier system described above according, for example, to the preparation modes, uses and compositions of topical liposomes described in Mezei, Topics in Pharmaceutical Sciences, Breimer et al. Eds., pp. 345-358, Elsevier Science Publishers BV, New York (1985), incorporated herein by reference, or according to the reverse-phase evaporation method described in Szoka et al., Proc. Nat. Acad. Sciences, vol. 75, pp. 4194-4198 (1978), and Diploses et al., J. Soc. Cosmetic Chemists, vol. 43, pp93-100 (1992), each of which is incorporated herein by reference. Solutions of oxa acids can also be entrapped in polymeric vesicles with a shell consisting of a suitable polymeric material, such as gelatin, cross-linked gelatin, polyamide, poylacrylates and the like, to form a vesicle that is then incorporated into the topical composition.
The compositions of the present invention may include an oxa acid compound as the only active ingredient, or may use the oxa acid compound in combination with other cosmetic and pharmaceutical actives and excipients. Suitable other cosmetic and pharmaceutical agents include, but are not limited to, antifungals, vitamins, sunscreens, retinoids, antiallergenic agents, depigmenting agents, anti-inflammatory agents, anesthetics, surfactants, moisturizers, exfolients, stabilizers, preservatives, antiseptics, thickeners lubricants, humectants, chelating agents and skin penetration enhancers, as well as the emulsifiers, emollients, fragrances and colorants discussed above.
Examples of suitable thickening agents include xanthan gum, xanthan gum brine tolerant, hydroxypropyl cellulose, hydroxyethyl cellulose, carbopol and gum acacia, Sepigel 305 (available from Seppic Co., France), vee-gum or magnesium aluminum silicate.
In topical compositions, oxa acids are also compatible with, and their utility can be enhanced by, humectants, such as urea, PCA, amino acids, certain polyols and other compounds with hygroscopic properties.
Topical compositions can also be formed to contain about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid, in combination with a keratolytic agent, such as salicylic acid and benzoyl peroxide, and skin lightening agents such as kojic acid benzoquinone, licorice derivatives, ascorbic acid and its derivatives (e.g. magnesium ascorbyl phosphate), and glycerhetinic acid and its derivatives.
From about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acid can be used to form a topical formulation in combination with organic and inorganic sunscreens, such as titanium dioxide, zinc oxide, benzylidene camphor, anthranilates, butylmethoxydibenzoylmethane, naphtholsulphonates and cinnamic acid derivatives. Of these, butylmethoxydibenzoylmethane and cinnamic acid derivatives are preferred.
Topical compositions of the invention can also contain about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids co-formulated with (i) retinoids such as retinol, retinoic acid, retinyl palmitate, retinyl propionate, retinyl acetate, isotretinoin as well as synthetic retinoid mimics; (ii) hormonal compounds such as estriol, estradiol, estrone or conjugated estrogens; (iii) alpha-hydroxyacids or polyhydroxy alpha-hydroxy acid such as glycolic acid, lactic acid, tartaric acid, gulonic acid and other carboxylic acids and their monomeric, polymeric, cyclic or acyclic derivatives; (iv) alpha-keto acids such as pyruvic acid, 2-oxopropanoic acid, 2-oxobutanoic acid, 2-oxopentanoic acid, and the like.
From about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids can also be utilized for additional benefits in topical formulations containing one or more of the following:
(i) vitamins including, for example, enzyme co-factors such as vitamin B6, vitamin B12, vitamin D3, 1,25-dihydroxy vitamin D3, vitamin B1, vitamin B2, vitamin K, vitamin E, tocotrienols and their derivatives, nicotinic acid and its esters, pantothenic acid and it esters, panthenol, folic acid and its derivatives, choline, carnitine and substances without formal vitamin status or xe2x80x9cpseudo vitaminsxe2x80x9d such as vitamin F or cis,cis-linoleic acid, vitamin M or pteroylglutamic acid, vitamins B10 and B11, sesame seed factor, termitin, penicin, insectine, hypomycin and mycoine, vitamin L or anthranilic acid, vitamin L2 or adenylthiomethyl-pentose, myoinositol or cis-1,2,3,5-trans-4-6-cyclohexanehexol and its esters, especially phytic acid, laetrile or 1-mandelo-nitrile-beta-glucuronic acid, amygdalin, vitamin B15 or pangamic acid, vitamin B13 or orotic acid, vitamine H3 or procaine hydrochloride, vitamin U or methyl-sulfonium salts of methionine, and pyrroloquinoline quinone;
(ii) antifungal-agents including, for example, clotrimazole, ketoconazole, miconazole, naftifine, tolnaftate, amphotericin B, nystatin, 5-fluorocytosine, griseofulvin, haloprogin, of which tolnaftate, haloprogin and miconazole are most preferred;
(iii) self-tanning agents including, for example, as dihydroxyacetone and lawsone, of which dihydroxy-acetone is most preferred;
(iv) anti-mycobacterial agents such as erythromycin, tetracyclin and related compounds, especially doxycyclin and methacyclin, cephalosporins, penicillins, macrolides, peptide compounds such as novobiocin, vancomycin, oleandomycin paromomycin, leucomycine, amphomycin with macrolide molecules, quinolone derivatives and other compounds that interfere with bacterial cell wall synthesis, membrane function, RNA metabolism, purine, pyrimidine and protein synthesis, respiration or phosphorylation;
(v) topical analgesics such as lidocaine, benzocaine, butacaine, tetracaine, clove oil and eugenol, of which benzocaine and lidocaine are most preferred;
(vi) lipidic compounds essential for the skin""s barrier function including, for example, ceramides, essential fatty acids and their esters, especially glycerides, xcfx89-hydroxy fatty acids and their esters derived with alkanols through carboxylic hydroxyl or with, other fatty acids at the omega-hydroxyl, the latter type being most preferred, with phospholipids, cholesterol and its esters, such as cholesteryl hemisuccinate and cholesteryl phospate of which cholesterol phospate and essential fatty acids are most preferred, phytosterols, cholestanol and its derivatives. The lipidic compounds can be added to a topical composition either as singular molecular entities or as a complex mixture of lipids derived from either synthetic, animal or plant sources; p1 (vii) antiallergenic agents and H1 and/or H2 antihistamines, such as diphenylhydramine, clemizole, antazoline, thenaldine, phenyltoloxamine citrate, tricyclic antiallergenics such as ketotifene, dithiadene and 3-thienylsulfide of thiadene, H2-receptor blockers, especially burimamide, metiamide and cimetidien, cromolic acid and its salts;
(viii) the oxa-acids can be used with topical anti-inflammatory agents that can reduce inflammation. These anti-inflammatory agents are used at concentrations from about 0.025 wt. % to 10 wt. %, preferably, 0.5 wt. % to 1 wt. %, with the concentration of the anti-inflammatory adjusted upward or downward depending upon the potency of the utilized agents. Examples of steroidal anti-inflammatories that can be used with oxa acids include hydrocortisone, hydroxytriamcilone, alpha-methyl dexamethasone, dexamethasone phosphate, beclamethasone dipropionate, hydrocortisone valerate, hydrocortisone cyclopentylpropionate, prednisolone, and mixtures thereof, with the most preferred being prednisolone and hydrocortisone; and
(ix) non-steroidal anti-inflammatories can also be employed, such as described in Rainsford, Antiinflammatory and Anti-Rheumatic Drugs, Vols. I-III, CRC Press, Boca Raton, Fla. (1985), and specific examples of suitable NSAID""s including, for example, oxicams (e.g. piroxicam, isoxicam), fenamic acid derivatives, meclofenamic acid derivatives (e.g. sodium meclofenamate), flufenamic acid derivatives, mefenamic acid derivatives, propionic acid esters, such as ibuprofen, naproxen, benoxaprofen, flubiprofen, ketoprofen, suprofen, of which ibuprofen is most preferred; pyrazolidinediones, of which phenylbutazone is most preferred; acetic acid derivatives, such as diclofenac, fenclofenac, indomethacin, sulindac, of which indomethacin is most preferred; salicylic acid derivatives, such as, for example, asprin, disalacid, and benorylate, of which aspirin and disalacid are most preferred.
The compositions of the present invention may also include safe anti-inflammatory products of natural origin shown to possess anti-inflammatory activity, such as aloe vera extracts, extracts from genus Rubis (Rubia Cordifolia), extracts from genus Commiphom (Commiphora Mukul), willow bark, matricarria flowers, arnica flower, comfrey root, fenugreek seed and the like known to those skilled in the art.
Topical compositions of the invention can contain from about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids in combination with antioxidants with phenolic hydroxy functions such as gallic acid derivataives (e.g. propyl gallate), bio-flavonoids (e.g. quercetin, rutin, aidzein, genistein), ferrulic acid derivatives (e.g. thyl ferrulate, sodium ferrulate), 6-hydroxy-2,5,7,tetramethylchroman-2-carboxylic acid. The compositions may also contain effective concentrations of water soluble antioxidants such as uric acid, reductic acid, tannic acid, rosmarinic acid and catechins.
Also of benefit is a coformulation from about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids with nitric oxide synthase inhibitors that reduce skin redness, vasodilation and inflammatory reactions, especially in response to electromagnetic and ionizing radiation or to the action of chemically or biochemically aggresive compounds. The nitric oxide synthase inhibitors can be added at concentrations from about 0.05 wt. % to 10 wt. %, most preferably from 1 wt. % to 3 wt. %, and selected from the group including guanidine derivatives, especially monoaminoguianidine and methylguanidine, L-arginine derivatives, especially NG-nitro-L-arginine and its esters, NG-monomethyl-L-arginine, 2-iminopipperidines and other 2-iminoazaheterocycles.
Other possible anti-oxidants that the composition may contain are those that have one or more thiol functions (-SH), in either reduced or non-reduced form, such as glutathione, lipoic acid, thioglycolic acid, and other sulfhydryl compounds. The levels of sulfhydryl anti-oxidants should not exceed 0.5 wt. % for cosmetic uses of the composition but may be higher for pharmaceutical uses as dictated by the considerations of efficacy. The composition may also include inorganic antioxidants, such as sulfites, bisulfites, metabi-sulfite, or other inorganic salts and acids containing sulfur in oxidation state +4. The preferred level of inorganic sulfur-containing antioxidants is from about 0.01 wt. % to about 0.5 wt. % with the most preferred level between about 0.1 wt. % and about 0.4 wt. %.
Compositions of the invention can also include from about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids coformulated with about 0.025 wt. % to about 5 wt. %, with 0.5 wt. % to 2 wt. % preferred and with 0.5 wt. % to 1 wt. % most preferred, of compounds known to be electron spin-traps such as nitrones, N-tertbutyl-nitrone and xcex1-(4-pyridyl-l-oxide)-N-tertbutyl-nitrone or other compounds known to form free radicals with half-life times of more than one minute.
From about 0.1 wt. % to about 90 wt. %, preferably from about 1 wt. % to about 50 wt. %, and most preferably about 5 wt. % to about 20 wt. % of the oxa acids can also be used in compositions that contain insect repellents such as, aliphatic, cyclic or aromatic amides, citronella oil, terpineol, cineole, neem oil and terephthalic acid and its esters. Other suitable insect repellents can be found in Technical Bulletin No. 1549 from the U.S. Department of Agriculture or in their Agricultural Handbook Nos. 69, 340 and 461.
The oxa acid-containing topical compositions of the present invention can also contain skin cooling compounds such as, by way of example, menthol, menthyl glycerol, asymmetrical carbonates, thiocarbonates and urethanes, N-substituted carboxamides, ureas or phosphine oxides such as described in J. Cosmet. Chem., vol. 29, p. 185 (1978), menthyl lactate, and menthone glycerine acetal.
The general activity and mildness to skin of the present topical compositions can also be enhanced by neutralization to pH 3.5 to 7.0, most preferably from pH 3.7 to 5.6, with one or more amphoteric and pseudoamphoteric compounds such as glycine, alanine, valine, serine, thionine, methionine, leucine, asparagine, histidine, glutamic acid, glutamine, lysine, cystine, cystein, tryptophan, serine, phenylalanine, citrulline, creatine, proline, 3- or 4-hydroxyproline, 5-hydroxylysine, ornithine and its derivatives, 3-aminopropanoic acid and other aminocarboxylic acids, canavanine, canaline, homoarginine, taurine, aminoaldonic acids and aminosugars, aminouronic acid, aminoaldaric acid, deacetylated hyaluronic acid, hyalobiuronic acid, chondrosine, desulfated heparin, neuraminic or sialic acid, methionine sulfone, glycylglycine, chondroitin, D,L-sphingosine, sphingomyelin, ophidine, glucagon, homocarnosine, phosphatidyl serine, cocoamphoglycine, phosphatidyl ethanolamine, cysteinesulfinic acid, glutathione, amphoteric inorganic oxides, polyamidoamines, polyamidoamine-based dendrimers, sodium hydroxymethylglycinate and polyethylene amine.
The utility and mildness of the present topical compositions can also be enhanced by certain chelating agents incorporated into the composition at levels from about 0.01 wt. % to about 25 wt. %, more preferably from about 0.5 wt. % to about 10 wt. %, and most preferably from about 1 wt. % to about 5 wt. %. Suitable examples of chelating agents include those that have a high affinity for zinc, calcium, magnesium, iron and/or copper ions, such as ethylene-diamine-tetra-acetic acid, (ethylenedioxy)-diethylene-dinitrilo-tetra-acetic acid, salicylaldoxime, quinolinol, diaminocyclohexane-tetra-acetic acid, diethylene-triamino-penta-acetic acid, dimethylglyoxime, benzoin oxime, triethylenetetramine, desferrioxamine or mixtures thereof.
The present invention also includes methods by which these compounds can be used to address the aforementioned skin conditions. Such methods include topically applying an effective amount of one or more compound of Formula (I) to the affected skin areas, normally once or twice daily. Such methods also include topically applying a composition containing an effective amount of one or more compounds of Formula (I) in a physiologically acceptable vehicle to the affected skin areas, normally once or twice daily. The methods of the present invention include the topical application of the compounds of Formula (I) in concentrations of up to 100%, when such compounds are a liquid at ambient temperature (e.g. 3,6,9-trioxaun-decanedioic acid), and when using the oxa compounds, for example, for skin peels or for softening hair.
The following examples are illustrative of the present invention and are not intended to limit the invention.

Oxa acids and related compounds for treating skin conditions

Abstract: wherein R4 is (CR5R6-CR7R81-X1)n-CR9R10R11; n is an integer from 1 to 18; R1, R2, R3, R5, R6, R7, R8, R9, R10 and R11, are independently, herein defined and X, X1, Y and Z are independently, 0, NH or S.


A lighting fixture (1010) has a fluorescent tube (1012) and a plurality of emitters (1022-1032). A color sensor (1016) detects light that has been totally internally reflected within a diffuser (1014) and provides a color feedback signal to a feedback control circuit (1020) to control the light output from the fixture (1012).

The present invention relates to an illumination control system for Light Emitters such as Light Emitting Diodes (LEDs), to lighting fixtures embodying such control and to methods of controlling Light Emitters.
The present applicant's earlier application WO 03/022009 (the contents of which are incorporated herein by reference) addresses, inter alia, an issue of colour coordination when multiple light sources at different wavelengths are combined to provide a composite output. Driving multiple light sources, such as LEDs, using Pulse Amplitude Modulation (PAM) provides appreciable advantages over alternative techniques such as Pulse Width Modulation (PWM) and Pulse Frequency Modulation (PFM)
The present invention provides a number of enhancements to the disclosures therein.
A first aspect of the present invention addresses the problem of how to obtain a feedback signal for an optical sensor from a plurality of light emitters.
In accordance with the first aspect a lighting fixture is provided comprising a plurality of light emitters whose light, in operation, passes through a cover and an optical sensor arranged to detect light that has been totally internally reflected in the cover.
The cover may be a lens, diffuser, scatterer or simply a protective layer of glass, plastic or any other suitable transparent or translucent material. The light that is totally internally reflected within the cover is a representative sample in terms of colour and intensity of the light passing through the cover. By arranging an optical sensor to capture some of this light, an effective optical feedback loop may be formed.
The term light used herein is intended to include light having a range of wavelengths e.g. in the visible part of the spectrum as well light having a specific wavelength e.g. photons and is to be construed accordingly.
Preferably, the light emitters comprise LEDs. The optical sensor may detect any suitable characteristic of the light reflected in the cover, for example the optical sensor may comprise a colour sensor and/or an amplitude (intensity) sensor.
Preferably, a feedback circuit is provided responsive to the output of the optical sensor to control the plurality of emitters. For example, to allow change and the control of correlated colour temperature (CCT) and colour rendering index (CRI).
Preferably, the arrangement of the sensor and feedback circuit is such that the lighting fixture automatically complies and maintains control of intensity and/or colour output of the plurality of emitters in accordance to predetermined characteristics.
Preferably, the plurality of light emitters include at least two different types, for example LEDs having a different characteristic wavelength (colour) or a different form such as organic and inorganic LEDs.
Preferably, the plurality of light emitters comprise at least one or more phosphor-light emitting diode(s) that emit a broadband visible spectral wavelength and at least one or more light emitting diode(s) that emit substantially monochromatic light within different wavelengths. This is beneficial for correlated colour temperature (CCT) and colour rendering index (CRI).
Preferably, a control circuit is provided comprising means for driving the two different types of LEDs to desired light intensities during coincident drive periods.
Preferably, means is provided to alter at least one of duration and repetition frequency of the drive period, for example the drive periods may start in response to an external signal.
Preferably, a drive circuit is provided for the plurality of LEDs, the drive circuit comprising power control means for controlling the amount of power supplied to at least one LED, means for measuring the intensity of the light emitted by the at least one LED, the power control means being responsive to the intensity of the light emitted wherein the power control means is arranged to drive the at least one LED at a power greater than specified.
Preferably, a temperature sensor is mounted in proximity to an LED to track the junction temperature thereof and a feedback circuit is preferably provided for ensuring that the power supplied to the LED is, at least in part, responsive to the junction temperature thereof. The temperature sensor may be mounted in the same package as the LED.
Preferably, a lighting control circuit is provided for intermittently driving the plurality of light emitters and receiving feedback information from at least one feedback sensor, the control circuit comprising means for ameliorating transient effects on the output of the feedback sensor, for example an averaging circuit.
Preferably, the means for eliminating transient effects include a delay between the actuation of at least one of the plurality of light emitters and the receiving of feedback information from the at least one feedback sensor.
Preferably, a lighting control circuit is provided for driving at least one LED and for receiving colour information from the optical sensor, the sensor being located to receive light from at least one other light source which does not comprise an LED, the control unit comprising means for driving the at least one LED in response to the colour information received from the sensor regarding the light from the at least another light source.
Preferably, the means for driving the at least one LED are further responsive to colour information received from the sensor which colour information is derived from light generated by both the at least one LED and the at least one other light source.
Preferably, the other light source is a fluorescent light source but other types of light sources may be employed for example, an incandescent light source, a high intensity discharge light source, a tungsten light source, a sodium light source, a metal halide light source and any other suitable light source.
Preferably, at least one or more thermoelectric cooling device(s) is provided to modulate the junction temperature(s) of the light emitting diodes and a microprocessor, field programmable gate array (FPGA) or digital signal processor (DSP) or an electronic logic circuit (ELC) adapted to control said thermoelectric cooling device(s).
Preferably, a current feedback monitor is provided for monitoring and correcting the current driving the thermoelectric cooling device(s) in response to the monitored condition(s).
Preferably, said at least one thermoelectric cooling device is a solid-state heat pump of the Peltier-effect type or a combined heat sink and electric fan unit.
Preferably, a light shaping diffuser is positioned to spatially arrange the light output of the illumination system and to provide a defined beam output that is spatially invariant in colour, colour temperature and colour rendering index properties.
Preferably, a multi-element light emitting diode beam collimating system is provided to convert wide beam angle light emitting diodes to narrow beam angle light sources.
Preferably, the multi-element beam-collimating system contains at least one non-imaging optic, preferably a micro-diffractive non-imaging optic, and at least one imaging optic for light emitting beam collimation.
Preferably, the collimated LED beam is combined with an adjustable multi-element lens system to allow the projection of images through an aperture wherein the outgoing beam angle can be adjusted. Preferably, more than two optical lens are employed. Preferably the collimated LED beam comprises a plurality of synchronised pulsed LED light sources.
Preferably, a data connection interface such as a TCP/IP type controller is provided enabling the fixture to be controlled through a standard computer network and the Internet.
A second aspect of the present invention permits sophisticated control based on ambient light conditions to be effected with little or no increase in component count compared with comparable approaches.
According to a second aspect of the invention, there is provided a lighting control circuit for pulsed driving of a plurality of light emitters and receiving optical output information from at least one optical sensor, the control circuit comprising means for receiving information concerning the light output of the light emitters while at least one of the light emitters is actuated and for receiving information concerning ambient light output when none of the light emitters are activated.
By the second aspect of the present invention, an optical sensor is arranged so that it detects both light issuing from the light emitters and also ambient light. The fact that, when using synchronized pulsed driving, there are OFF periods in which no light is produced by the light emitters means that the same sensor can be read during this period to provide an ambient reading. Control circuitry may then exploit this extra information to effect the control of the light emitters. This may be of particular relevance in the automotive field where collisions are particularly common at dawn and dusk. By factoring in the ambient light conditions, the control circuitry may be arranged to provide a safer environment for the driver.
Preferably the circuit further comprises a feedback circuit for controlling the drive to the plurality of light emitters in response to the actuated light output and ambient light output.
According to a third aspect of the invention, there is provided a lighting control circuit for driving at least two optical emitters having different wavelength characteristics and for receiving a signal from a sensor which sensor can detect wavelength information, the control circuit comprising means for altering the amount of drive applied to the at least two optical emitters in response to colour information derived from the sensor.
Preferably, the one or more sensors consist of a plurality of Silicon PIN diodes with appropriate wavelength filters or a plurality of organic light detectors with appropriate wavelength filters or a spectrometer or a solid-state colour camera detector.
Preferably, the one or more sensors consist of a device that efficiently converts photon energy into electrical energy at predefined wavelength intervals. For example, the photon energy may be converted into electrical energy that represents one of two states, either to provide the electrical energy of the sensor as a representation of the photon energy seen by the human eye, or a representation of the true optical power.
A fourth aspect of the present invention addresses a problem of limited operating range. It is well known that LEDs are non-linear devices and if they are driven at too low a voltage they will, at best, be somewhat inefficient in terms of light output per electrical power input and at worst will fail to generate any light at all.
The fourth aspect of the present invention addresses this by providing synchronised driving waveforms in which at least one additional operating regime is added to the operating range. In this regime the period and/or the mark-space ratio of the pulse driving signal is altered from that used in a pure PAM regime.
A fifth aspect of the invention addresses applications in which a minimum light output is required. Once such application is automotive lighting in which the minimum light output will typically be specified by the relevant regulatory body. A difficulty arises where the light output deteriorates over time such as is the case with LEDs. (Compare this with the catastrophic failure that occurs when filament lamps reach the end of their lives). Because the deterioration of light output will be gradual it will probably not be discernible to the user, or in the case of the car, a driver. While the diminished light output will be detectable at a roadworthiness test station using special equipment, such tests are typically not conducted very frequently and so a considerable period of time could elapse without a driver realising that his or her lamps are dimmer than they ought to be.
According to the fifth aspect of the present invention there is provided a drive circuit for at least one LED which also has means for receiving an intensity measurement of the light emitted by at least one LED. By driving the LED or LEDs in a fixture to higher and higher currents (beyond the recommended values specified by the manufacturer) the light output will be maintained at an acceptable intensity beyond the period of useful life of the LED or fixture. In addition, the increased power supply to the LED will eventually cause thermally-induced failure and it will then be clear that the LED or fixture needs replacing. This aspect of the invention, therefore, not only extends the useful life of an LED or LED fixture but also ensure that the LED or fixture are replaced in a timely fashion.
A sixth aspect of the invention provides enhanced thermal feedback. In the applicant's previous patent application, WO 03/022009, temperature sensors are disclosed for the purpose of measuring ambient temperature. However, the inventors have now come to appreciate that it is also important to measure the junction temperature of the LED. In high-power and high-efficiency LED lighting systems the junction temperature is an important control parameter. However, measurement of the junction temperature directly has not hitherto been possible.
According to the sixth aspect, a temperature sensor is provided in sufficient proximity to the LED billet to track the junction temperature thereof. The present inventors have discovered that by mounting a temperature sensor sufficiently close to the LED billet (possibly even within the same housing) the detected temperature is found to track the junction temperature with a negative offset of around 5° C. over the temperature range of interest.
A seventh aspect of the present invention is concerned with improving the quality of the feedback signals in the closed loop control circuits for light emitters. Particularly in noisy environments and as drive pulses become shorter, there is a danger that feedback signals, be they current feedback, temperature feedback or optical feedback, will be corrupted by transient effects.
This is addressed, in accordance with the seventh aspect, by sampling at a given delay and/or integrating (low pass filtering) the feedback signal prior to feeding the signal to the control circuitry.
According to an eighth aspect of the present invention a wavelength or colour detector is provided to sample the combined output of at least two different LEDs having different wavelengths, the drive to the at least two LEDs being responsive to the output of the detector. One possible arrangement is that at least two LEDs comprise a white phosphor-based LED and a monochromatic LED.
According to a ninth aspect of the present invention an LED compensation system is provided for another type of light emitter such as a fluorescent tube. By sensing the colour of the output of the tube (and preferably the colour of the light from the tube and LEDs combined), control of, inter alia, colour temperature may be effected. This may be used to compensate for aging and/or to customise the characteristics of a fluorescent (or other) fitting.
According to a tenth aspect of the present invention a lighting system is provided comprising at least one LED light source and a collimating system to produce a collimated light output from said at least one LED light source.
The collimating system may comprise a light shaping diffuser. The light shaping diffuser may be combined with a multi-element micro-refractive optic.
In another arrangement, the collimating system may comprise a non-imaging element and an imaging element. The non-imaging element could consist of a micro-diffractive optical system or a holographic optical element.
The collimated light output may be employed in a light projection system to provide a projected image of an aperture or object placed at the aperture.
According to an eleventh aspect of the present invention a lighting control system is provided in which a controller is utilized to control one or more remote lighting fixtures via a data connection interface.
According to a twelfth aspect of the present invention apparatus comprising a plurality of light sources, preferably synchronized collimated LED light sources, combined with an adjustable multi-element lens system capable of varying the outgoing beam angle.
Preferably, the apparatus can be employed in a projection system for the projection of images through an aperture.
FIG. 1 shows driving waveforms of four colour channels covering red, green, blue and amber parts of the visible spectrum that are driven by a PWM technique. It is clear that for particular colour settings, the LED cluster will exhibit several different colours and intensities that makes it impossible, especially for use with solid state TV cameras, to adequately control colour, intensity, correlated colour temperature (CCT) and colour rendering index (CRI). FIG. 1 assumes that all colour channels are synchronised at TO but in practice this may not occur and further colour and intensity discrepancies would result.
FIG. 2 shows an alternative method for driving LEDs, that of Pulse Frequency Modulation (PFM). PFM utilises pulses of equal amplitude and duration that are generated at a rate determined by the signals' frequency but again this technique does not enable true colour mixing or precise CCT control when two or more wavelengths or colours are used within an LED cluster. The figure illustrates how using PFM leads to very poor colour mixing, CCT and CRI properties as well as different signal frequencies for each colour channel.
An additional method of driving LEDs is that of Pulse Amplitude Modulation (PAM) which controls the current through each LED colour channel by varying the amplitude of the current. This method has many advantages for driving LEDs such that all of the colour channels can be pulsed at exactly the same time enabling true control of colour mixing, CCT and CRI. FIG. 3 illustrates such PAM driving waveforms. While square waves are shown it should be noted that other waveforms such as trapezoidal or even analogue waveforms such as sinusoidal may be used.
FIG. 24 illustrates the principles underlying the first embodiment of the invention by way of a timing diagram. FIG. 24(a) shows the PAM driving waveforms for red (R), green (G) and blue (B) emitters at a low intensity. Unfortunately, since LEDs are non-linear devices, driving them at very low current levels results in inefficient driving or in extreme cases, no driving at all.
To address this, the present embodiment may vary the pulse width of the driving waveforms. FIG. 24(b) illustrates the same amount of power being applied to each of the three colour channels but the power is located in pulses of around half the previous duration. The intensity of the drive can thus be increased to a level at which each LED or LEDs are driven in a more efficient, or in a preferred arrangement linear, operating region. Because the duration of the pulses has been reduced, the overall light output is still at the (low) desired level.
FIGS. 24(c) and 24(d) illustrate the opposite scenario in which a very high intensity is required and this may even be sufficiently high to place the LEDs themselves at risk. Instead of using the 50% mark-space ratio shown in FIG. 24(c), the pulse ON time is lengthened within a cycle to permit a lower absolute drive amplitude to be applied to the LEDs. This is shown in FIG. 24(d).
Alternatively, the width of the individual pulse may be maintained while altering the pulse repetition period (lengthening for low light values and shortening for high light values). As in the first alternative, this permits an appropriate level of drive to be applied to LED or LEDs for a given power output. Note that this differs from PFM in that the colour outputs remain synchronised.
Both the PWM and PFM techniques are widely utilised within LED based lighting and display applications as they often assume that the light will be received by the human eye. As the human eye (FIG. 15a) has an integrating function, it is assumed that colour discrepancies will not be noticed provided the pulse repetition frequency is above a few hundred Hertz. However, this is not applicable to solid state camera systems in which illumination of the subject using PWM will result in flicker and poor colour balance. It should also be noted that the current generation of high brightness inorganic semiconductor LEDs available from LumiLEDs Lighting of San Jose, Calif., USA advise using somewhat lower modulation frequencies than this.
FIG. 4 shows a block diagram of an illumination control system 100 according to the first embodiment. The system comprises a microprocessor 1 used to control the system and to generate amplitude modulation signals in response to inputs from a temperature sensor module 2 and a colour sensor module 3. A load drive section 4 receives inputs from both the microprocessor 1 and the load current feedback module 6. It also has an output connected to the load 5 which in turn provides an output to the load current feedback module. An optional thermoelectric drive section 7 has inputs from the microprocessor and a cooling load feedback module 9. The section 7 has an output connected to a thermoelectric load module 8 which in turn provides an output to the cooling load feedback module 9. An optional communications module 10 provides bi-directional data communication between the microprocessor and one or more external devices or controllers. An external lighting synchronisation module 11 is provided to form an interface to an external synchronisation signal such as from a solid state camera when such synchronisation is required.
A temperature sensor module 2 includes a plurality of temperature sensors (13), the colour sensor feedback module 3 includes at least one and preferably a plurality of colour sensors 12 and the load drive section includes at least one and preferably a plurality of load drivers (not shown) for driving a plurality of loads. The load current feedback module comprises a plurality of load current feedback sensors while the thermoelectric drive section 7 includes a plurality of thermoelectric drivers (not shown) used to drive a plurality of cooling loads 16 and the thermoelectric current feedback module contains a plurality of cooling load current feedback sensors.
The embodiment operates as follows. A required light intensity and colour are received from an external controller via communications module 10. The microprocessor then calculates the appropriate drive intensities for each of the different colour channels within the system. In doing so, any feedback from the optical colour feedback module 3 will be taken into account. The microprocessor will then determine the drive current, pulse width and pulse repetition frequency that best matches the required intensities in each channel. For instance, that channel with the lowest required intensity must be driven at a sufficiently high drive level to ensure illumination, while that channel at the highest required intensity must not be driven to such a level (considering the thermal feedback from the temperature sensing module 2) that the Load LEDs are jeopardised. Once appropriate pulse widths and intensities have been calculated, the load drive section 4 is instructed to apply the appropriate pulses to the loads—always within the requirement that the duration and timing of the pulses on each channel are the same. This results in synchronised control.
Where one or more colour channels require a much lower drive intensity than other channels is may be appropriate not to drive some of the LEDs in that or those colour channels.
The Load Drive Section 4 and the load current feedback module 6 cooperate to control the current through the load LEDs to ensure both adequate drive and overload protection.
Referring to the block diagram of FIG. 5 a second embodiment of the illumination control system 100 is shown. In this embodiment the communications module 10 communicates not with a microprocessor but with a logic control circuit embodied in an ASIC 91. In this embodiment the temperature feedback is applied to the load drive section 4, as is the optical colour feedback from module 3. The optional thermoelectric drive section has been omitted.
The ASIC 91 is designed to perform the functions (with the exception of the temperature and colour feedback) previously performed by the microprocessor in the first embodiment. The ASIC may comprise a small, cheap Field Programmable Gate Array (FPGA) such as the Xilinx XC9572XL from Xilinx Inc. San Jose Calif., USA to a mixed signal ASIC carrying additional circuitry for the illumination control system and even further circuitry for any system integrated therewith.
FIG. 6 shows an embodiment of a pulse signal generator 21 which provides a pulse modulator clock signal output 19 to the load drive section 4 and a corresponding sample-and-hold output signal 20 for the load current feedback module 6. The pulse modulator clock input may be derived from either the microprocessor 1 or an ASIC 91 with a defined frequency and duty cycle. The frequency and duty cycle may be programmed by changing data values held within registers of the microprocessor 1 or by timing synchronisation pulses within the ASIC 91 to enable the illumination system 100 to vary its frequency or duty cycle according to the in tended application. An application brief from Agilent Technologies entitled PULSED OPERATING RANGES FOR ALINGAP LEDS VS PROJECTED LONG TERM LIGHT OUTPUT PERFORMANCE recommends typical duty cycle ratios for common LED-based applications. By utilising one or more output pins located on the microprocessor 1 a highly stable duty cycle and frequency can be achieved which in turn enables precise control of colour synchronisation and therefore CCT and CRI. Additional advantages are a reduction in external component requirements and the ability to change the frequency and duty cycle from software operating on the microprocessor 1.
In general the illumination control system will be operated in a non-continuous pulse mode of operation that will provide current to the LED loads 15 through the load drive section 4. In practice the load current feedback circuits will benefit from amelioration of transient effects in the sensed current. In this embodiment this is achieved using a sample and hold circuit to ensure that the pulse modulated colour synchronised current feedback control signal is maintained during a time period when the Load LEDs are not energised. Without such a circuit, the control system is likely to see transient switching voltages which could result in unsettled drive currents through the loads 15 producing variations in the intensity of the LED light output. A delay is advantageously added to reduce the effect of the initial switching transient.
An inverted and time delayed clock signal relative to the pulse modulator clock signal 19 is thus derived. The sample and hold output signal 20 and clock output signal 19 can be created using NPN transistor Q1 and resistor R2 to invert the pulse modulator clock signal input from a microprocessor 1 or ASIC 91. The inverted signal is buffered and inverted by the dual input NAND gate (U1a) with its output connected directly to both inputs of NANDgate (UIc) and also to one of the inputs of NAND gate (U1b) and to the other input of the NAND gate (U1b) via resistor (R3) capacitor (C1) network. The resistor capacitor (RC) network provides a time delay according to a well known formula and typical values of R3 is 68 kOhms and C1 is 1 nF which provides a time constant of around 68 microseconds. The signal is then inverted and delayed again by U1c and the RC network R4 and C2 with a final inversion by NANDgate (U1d) to create the pulse modulator clock signal output 19 that represents the ON portion of the duty cycle in FIG. 3. To those of skill in the art, selection of appropriate component values can be performed to accommodate values of maximum and minimum desired values of modulation signal frequency. Equally, alternative circuits to perform the requisite function could readily be designed the skilled person.
This technique is also applicable to the other feedback circuits within the system such as the colour feedback circuit.
FIG. 7 shows the electrical schematic of an embodiment of the load drive section 4 with a load current feedback module 6 whereby a pulse modulated colour synchronised control signal 30 is formed to drive a voltage controlled current source or load driver (31), such as an n-channel MOSFET through a differential amplifier (U3a) and analogue switching arrangement (U4a, U4b). The pulse modulated colour synchronised control signal is created by combining the amplitude modulated control signal 27 using the output of a Digital to Analogue Converter (DAC) U2 and the current feedback control signal is generated using a sense resistor, which is consequently pulse modulated by employing an analogue switching network using the pulse modulator clock signal outputs representing the time periods Ton (19) and Toff (20).
An exemplary DAC is the 14 pin TLC5620 with serial programming interface available from Texas Instruments Incorporated, Dallas Tex., USA. In the current embodiment the DAC is used to generate an amplitude modulated control signal 27 in the form of a voltage output, which is created as a proportion of the DAC3s input reference voltage 26 using an 8-bit data register representing one of 256 different voltage levels between ground and the DAC's reference voltage input. Therefore, by selecting the appropriate value to be stored in the DAC's data register an amplitude (or voltage) of the pulse modulated colour synchronised control signal 30 can be altered accordingly. The DAC's input reference voltage 26 may be generated using a standard voltage divider arrangement containing two resistors R5 and R6 in series between the logic supply voltage and Ground. A typical value for R5 and R6 is 2 k2 Ohms, which provides a DAC input reference voltage 26 of approximately 50% of the logic supply voltage, or 2.5 volts. From the foregoing description it will be appreciated that the DAC's input reference voltage 26 may be provided using alternative techniques.
The amplitude modulated control signal 27 output is modified by programming the DAC (U2) using a serial interface which is connected to a microprocessor 1 or ASIC 91. To program the DAC with a new output voltage the microprocessor or ASIC sets the DAC Load control line 22 high and then clocks in a command byte followed by a data byte on the DAC Data line 24. Once all the bits have been clocked in, the DAC load control line is pulsed low to transfer the data from the serial input register to the selected DAC data register. When the DAC LDAC control line 25 is set high during serial programming and then pulsed low the DAC data register value is transferred to the DAC output directly. The DAC LDAC control line 25 enables each of the four DACs outputs to be updated simultaneously enabling precise synchronisation of all DAC output channels. The command and data bytes are clocked into the DAC (U2) on the falling edge of the DAC clock line 23 provided by either a microprocessor or ASIC. FIG. 8 is a timing diagram illustrating the sequence for programming the DAC, where the command bits are set to instruct to write the data contained within the data byte to the DAC determined by the channel select bits A0 and A1. The range bit RG controls the DAC output range. When RING is set low, the output range is between the applied reference voltage and GND, and when RING is set high, the range is between twice the reference voltage and GND.
Referring to FIG. 7, the amplitude modulated control signal voltage is fed to a non-inverting amplifier (U3a) configured to provide a continuous differential output voltage generated by the voltage difference between the amplitude-modulated control signal voltage 27 and the current feedback control signal voltage 28. The current feedback control signal voltage is generated by a load feedback current sensor 14 in the form of a sense resistor (Rsense) used to measure the current flowing from a power source (+Vdd) through the load 15 and the load driver MOSFET 31 to GND. The sense resistor may be connected between the source terminal of the load driver MOSFET and ground to generate a small voltage (Vs) which is proportional to the load current that flows thorough the load 15. A low value is preferred for Rsense to minimise dissipation and the resistor commonly comprises a discrete metallic resistor with zero temperature coefficient such as manganin or constantin. The sense resistor may comprise a portion of track on the Printed Circuit Board (PCB).
A pulse modulated colour synchronised control signal 30 is created by connecting the output voltage from the differential operational amplifier (U3a) stage to the input (B1) of a two-channel, single-pole double-throw analogue switch (U4a) through a resistor (R13). The second input (DO) of the analogue switch (U4a) is connected directly to circuit ground while the output (A) of the analogue switch (U4a) is connected to the gate electrode 30 of the load driver MOSFET 31 through a coupling resistor R9. The control input (S) of the analogue switch (U4a) is connected to the pulse modulator clock signal output 19 which connects the appropriate input DO or D1 of the analogue switch (U4a) to the output (A) according to the logic level 0 or 1 of the pulse modulator clock output signal 19 respectively. During the ON period Ton, of the pulse modulator clock output signal 19 the analogue switch (U4a) output (A) is connected to the coupling resistor (R9) and charges the capacitor (C3) which produces a voltage potential proportional to the output voltage of the differential operational amplifier (U3a). However, during the off period, Toff, the analogue switch (U4a) output (A) is connected to circuit ground and ensures that the load driver MOSFET 31 does not allow current to pass through the load 15. The voltage potential across the capacitor (C3) remains stable and does not discharge during the time period, Toff, as the inputs D1 and BO of the analogue switches U4a and U4b become high impedance ensuring little or no current discharge occurs.
During the off time period, Toff, of the sample-and-hold output signal 20 the input DO of the analogue switch (U4b) is connected to output (A) and hence to the coupling resistor (RIO) enabling the voltage potential (Vs) across the sense resistor (Rsense) or current feedback control signal voltage 28 to appear at the negative input of the operational amplifier (U3a). A protection diode (D1) is used to protect the operational amplifier (U3a) from negative voltage spikes that may occur during a failure of the microprocessor 1 or ASIC 91. Accordingly, during the on time, Ton, of the sample-and-hold output signal 20 the input (D1) of the analogue switch (U4b) is connected to output (A) leaving a high impedance state at the input (DO). The capacitor (C3) ensures that a voltage is maintained during the timing period, Toff, of the pulsed modulated colour synchronised control signal and therefore does not require a large transition current through the load driver MOSFET when entering the timing period, Ton, thus ensuring the current through the load 15 is stable.
A Zobel filter is present across the load drive signal 33 and the circuit ground in the form of resistor (RI I) and capacitor (C4) in series. The presence of a Zobel filter ensures that the load 15 appears resistive at high frequencies and helps to ensure oscillation is attenuated at high frequencies. Typical values for the resistor (RI 1) in 10 Ohms and capacitor (C4) is 10 nanoFarad.
In one alternative embodiment of the load drive section 4 and the load current feedback module 6 shown in FIG. 9, the continuous amplitude modulated control signal 27 is generated by combining two timing signals (one timer represents frequency and the other duty cycle) to form a timing control signal 90 from a microprocessor 1 or ASIC 91. The timing control signal is then integrated through a low pass filter in the form of a resistor/capacitor network. The foregoing embodiment has considerable advantages in practice as the DAC uses low cost passive components and the DAC resolution is software-configurable. Alternatively, the timing control signal 90 may be generated by a dedicated PWM timer within the microprocessor I or ASIC 91 and produces continuous output voltage with an amplitude resolution proportional to the resolution of the input timing control signal 90. Similar DAC conversion techniques are well known to those skilled in the art.
In yet another separate embodiment of the load drive section 4 shown in FIG. 10 up to 4 separate load driver 4 and four separate load current feedback sensor 14 channels can be are used to invert the serial line data input 57 and slow down the transistor operation. Typical values for capacitor CS and resistor R14 are 100 pF and 22 Kohms respectively.
FIG. 21 shows a lighting arrangement 1010 in accordance with an embodiment of the present invention. A fluorescent tube 1012 is shown arranged in traditional fashion between a reflector 1036 (shown in section) and a diffuser 1014. Light output from the tube passes through the diffuser either directly or via the reflector which is typically shaped and arranged to minimise the amount of "wasted" light.
However, such fluorescent tubes deteriorate with age and, to counter this, a feedback circuit 1020 and six LEDs 1022-1032 are provided to compensate. The diffuser 1014 is provided with a colour sensor 1016 which detects light that has been totally internally reflected within the diffuser. This light will be representative of the light passing through the diffuser and so the output of the sensor 1016 provides a colour feedback signal to the feedback control circuit 1020 via signal line 1018.
The feedback control circuit is arranged to respond to the output of the colour sensor 1016 to control the light issuing from the fixture. To this end the circuit 1020 is connected via line 1034 to six amber LEDs 1022, 1024, 1026, 1028, 1030, 1032 which are mounted in the reflector 1036. Because of the nature of the deterioration of fluorescent tubes, adding some amber light provides compensation for the aging process. As the tube 1012 deteriorates still further, a greater amount of light will be provided by the LEDs to compensate. The closed loop feedback provided by the colour sensor 1016, feedback control circuit 1020 and the LEDs allows at least one colour parameter (for example colour temperature) to be consistently maintained.
The fluorescent tube 1012 may be arranged to be separately removable since the lifetime of such tubes is typically 1000 hours while the lifetime of LEDs is typically 10000 hours. Alternatively, since LEDs are comparatively cheap, they could be incorporated with the tube and discarded when the tube is renewed.
While the colour sensor 1016 is shown as sensing the output from the whole fixture, i.e. the fluorescent tube and the LEDs, it is possible for the sensor to be arranged to detect only the output from the fluorescent tube.
While this embodiment has been described as providing compensation for the aging of the fluorescent tube, it should be noted that it could equally be used to set a desired characteristic, such as colour temperature, for a tube of any age. Since fluorescent tubes are currently provided in various colour temperatures for various purposes, this would allow manufacturers and dealers in fluorescent tubes to reduce their inventory with attendant reduction in cost.
Moreover, this embodiment of the invention may equally be applied to other non-LED sources of light that deteriorate with age or which would benefit from the ability to provide custom colour features such as incandescent lamps.
FIG. 22 shows another embodiment 1100 of the present invention that exploits the total internal reflection of light within a diffuser, lens or cover. The control circuitry has been omitted for clarity. The embodiment may preferably be a headlamp for a car but this aspect of the invention is applicable to a wide range of lighting fixtures.
A circuit board 1102 carries a number of LEDs of which five 1104, 1106,1108,1110 and 1112 are shown. Light from these LEDs passes through a cover 1114 which may be a lens, diffuser etc. constructed from glass or plastics. By the nature of such an arrangement, some of the light incident upon the cover 1114 will be totally internally reflected within the cover as depicted by the zigzag lines. A portion of this totally internally reflected light will impinge upon an optical sensor 1116 mounted somewhere on the periphery of the cover.
The sensor 1116 could be a colour sensor as used in the embodiment shown in the previous figure or it might simply be an intensity sensor an required by the following embodiment. By utilising such as sensor, the collective output of a large number of LEDs may be sensed using a single sensor. This has the benefit over mounting one or more sensors on the circuit board of sensing the entire light output and will not be distorted by the performance (or otherwise˜of individual LEDs.
FIG. 23 shows a diagrammatic graph of LED light intensity 1202 and drive current 1204 over time.
Imagine that light intensity 1202 is generated in response to current 1204 towards the left hand side of the graph. In the case of a car headlamp, for example, there is a minimum acceptable intensity value determined by the regulatory authorities. In other applications there will be a minimum specification of light output and this value is illustrated by the horizontal broken line 1206.
After a long usage time the output of the LED will deteriorate as illustrated by the downward turn of curve 1202 at time A. At time B the intensity of the LED output falls below specification. One possibility here would be to detect this and light a warning light on the dashboard of the car (or somewhere else on another, non-automotive, light fitting) to inform the driver that his or her lighting unit needs to be replaced. However, this would quite likely be ignored as the deterioration in intensity would probably not be discernable to the driver.
In the present embodiment, this is addressed by increasing the current drive provided to the LED at time B to cause the light intensity to follow the dot-dash line 1208 (i.e. continue at or above the minimum output level). As a consequence of this the LED will fail catastrophically at time C as shown by the line 1210. The advantages are that the lifetime of the LED is extended beyond that at which it fails to perform to specification and the catastrophic failure ensures that the driver or other user has to replace the LED, lighting unit or fixture and cannot continue to operate a failing unit with the attendant safety implications.
Conventional LED devices usually emit a radiant light pattern at large beam angles that restricts their use for applications where a defined beam output is required. FIG. 25 shows a LED beam collimating system 200 that provides a degree of illumination beam output control to convert the light output from a LED source 220 to a more usable light source with collimated light output characteristics.
As shown a light shaping diffuser 210 can be placed directly in front of the LED light source 220 containing LED's of different wavelength characteristics 230, 232, 234, 236 to enable the light output of the illumination system to be spatially invariant in terms of colour, colour temperature and colour rendering index properties.
The light shaping diffuser 210 could also be utilised to change the beam pattern of the LED beam collimating system 200 from a typical Gaussian beam output to a square, elliptical, line or some other required beam profile.
FIG. 26 shows how a multi-element LED beam collimating system can be utilised to convert one or more wide beam angle LED's to a narrow angle light source providing a highly collimated LED beam output by utilising a combination of multi-element micro refractive elements 300 aligned to the LED dies contained within the LED source 320 and a light shaping diffusing element 340. Combining a multi-element micro refractive optic and a light shaping diffuser enables a compact, lightweight highly collimated LED source to be obtained.
Referring now to FIG. 27, a further embodiment of the invention is shown incorporating a configuration whereby a non-imaging diffractive 400 and an imaging element 420 are combined to provide a highly collimated beam output from the LED source 430.
The non-imaging element 400 could consist of a micro diffractive optical system or a holographic optical element to concentrate the light emitted from the LED source 430 without maintaining any of the spatial characteristics of the LED's 440, 442, 444, 446. The second imaging element 420 could consist of a lens and provides enhanced collimation and beam control.
This arrangement enable the use of the LED light source 430 in a large number of lighting application such as image projection systems, whilst maintaining high light efficiency.
FIG. 28 shows a light projection arrangement 500 in accordance with an embodiment of the present invention. A LED source 510 is shown with an arrangement containing an array of one or more LED emitters 520, 522, 524, 526. The light output from the LED source 510 passes through a multi-element light emitting diode beam collimating system 530 into an aperture arrangement 540 that can contain an object that can be projected using a series of imaging lenses 550, 552, 554 that can be continuously adjusted to provide a projected image of the aperture or object placed at the aperture with a continuously variable beam profile output. The imaging lenses 550, 552, 554, may contain a combination of aspheric or spherical surfaces to provide the required imaging properties.
This arrangement utilises the advantages of non-imaging and imaging optics to provide a highly efficient compact, low cost, low weight lighting projection system.
FIG. 29 shows another embodiment of the invention whereby a plurality of lighting fixtures 620 are controlled and coordinated utilising a system 600 through the use of a Local Area Network (LAN), a Wide Area Network (WAN) 610 or the Internet utilising 630 TCP/IP protocols.
This communication technique provides a considerable advantage as standard IT infrastructures may be utilised to control a large network of lighting fixtures in a variety of topologies with low cost.
For example, one controller 600 could be connected via the Internet 630 to a remote site located anywhere in the World, shown as 640 & 650, and control the lighting scene automatically and communicate lighting fixture control and diagnostic information in real time mode.
The various aspects of the invention described herein are applicable, unless the context indicates otherwise, to PAM driving techniques and, albeit with possible reduction in performance, to PWM, PFM and other non-PAM driving techniques.
The present disclosure extends to any novel feature or combination of features disclosed herein whether express or implied and to any generalisation thereof.

Illumination control system for light emitters