'96-03-07 16:35 FR0~ 2Jl`` ~ ~*.~ . 2 i / 1 L 4 4 P.5~42 ~arlable Color LED Device and LED Color Control D-vic~
Ba~hy~ d of the Invention Field of the Invention The present inven~ion relate~ to a variable color LE~ d~vice which emits various coloxs and ~n LED ~olor control de-vlce for controllin~ the emissi~n (vari~tions and in~ensi~y of color~) from the va~iable color ~ED device.
Descri~ion ~f the ~lated Art There have been lu~inescent element~ used conventionally wi~h various colored ligh~s (for ~xample, red, green). Particularly, ~ light emitting ~iode (LED) has be~n ~ell-known as a small a~d power-sa~ing device, ~na is use~ for various d~splay devlce~.
FI~ lA ~hows a top ViQW of a conventional LED
device. FIG. 1~ shows the cur~ent control cir~uit o the L~D d~vice. A~ L~D device 1 shown in FIG. lA
comprises d substr~te 2 provided with a luminescent diode 3. The lurineccent d~ode 3 is covered with a lens-shaped prote~tive transmission oover. A curren~
~ontrol circult is connected to the LE~ deviee 1 as 25 ~hown in FIG. lB. The ~urrent ~ontrol circui~
l6-03-07 16:35 FROM:~ *.:~4:~. 2 i / P.6~4Z
oomp~ ~e6 tel In~l units 4 an~ 5 an~ a vari~bl~
re~i~tanCQ 6. The termlnal unlts ~ and 5 are - co~na~t~d to a power source with the termin~l unit 4 directly connected to the cathode of the luminescent diode 3, and with the terminal unit 5 connected to the ~node of the 1~ e~cent dlode 3 through the variable resistance 6. The above described term~nal units 4 and 5 ~re connected to th~ extern~l power sourc~ ~not ~hown in ths attached dr~wings). When ~ bias voltage i~ applie~ in the forward directlon with the above descri~ed ocnfiguration, the lum;nescellt diode 3 e~it~
light. The color of the e~itted li~ht depends on the mat~rial of the configuration of the luminescent diode 3. For example, when the con~i~ur~tion refers to Ga-As in the p-n junotion, an i~xaxed light is emitted.
When the configu~ation ~e~ers to G~-P with an 02-dop~d ~miconduc~or, a red light is emitted. When the configuration refers to Ga-P with an Na-doped samiconductor, a g~een co~or is emitted. Furthermore, a luminesGent diode emittin~ a blue light h~s ~cently b~er~ developed for pract~cal use. The qu~ntity of llght emltte~ by a luminescent diode dep~nds on the electric current flowin~ through a bia~ électric voltage. Therefore, ~he quantity ~f lig~t ~an b~
changed by con~rollin~ the re~is~ance value of the ~-03-07 16:35 FRo~ 2~ Y*~ 4~ Ll 7 1 ~ q ~ F.7,'~2 var$able xesi~tance 6.
Such ~n LED device ~s dcsi~ned to emit li~ht of a single color irom a ~in~le unit. For example, even i a plur~lity of l-lr;n~R~ent diodes ~re mounted in a æinyle LED device, the lumine~cent diodes are to emit light of q single (same) color.
Assumin~ that such LED device~ are incorporated into ~ display device as picture elements, t~e pictu~e elements of a commvn di~lay device should be for lC~ v~ious colors. Therefore, acc:ording to the related a:rts, LED devic;es separ~tely emitting one o~ primdries ~re provided in three devi~e units t~ obtain a desired colo~ by mixing the luminescent c:olor~ from the three LEI;) devices. One LED device i~ ~bc~ut 3 - 5mm in diameter. The~efore, a combination of 3 LED devices fo~ optlcal th~ee primary colors makes a display picture elemen~ as ~ig as a circle circumscribing ths three LED devices. As a result, one ~isplay picture elem~nt iR l~ - 15mm in diameter.
It is 4 times as bl3 as a single L~ device, and is rath~r '~r~e as a display pic~ur~ element. Even if the three L~D devices are mounted closely to ea_h other, the clear~nce ~etween ~he luminescent diodes cann~t ~e small enough to appropriately mix optical three primary colors. ~he~eforOE, ~vsn i~ the mixed ~6-~3-07 16:36 FRo~ 2~ *~ P.8~42 2 ~ 4 ~
color may b~ ~c~eptable when viewed ~ro~ a distan~:e, it has the prob~em when viewed closely t~t op~ical thre~ primary colo~s c~nnot be sufficiently mixed, but are re~gnized separately. Under ~uch conditions, forming a displdy device using con~entional ~
devi~es, each of which cor~e~ponds ~o a di~lay picture e1e~ t, ~akes up ~ ver~ l~rge d1splay device, the~eby un~avorably li~itiny the use ~f the davioe to th~ case ~here the dev~ce is viewed from a dist~nce.
Furthermore, the LE~ devices for ~hs abov~
de~crib~d combin~tion should be pro~ded ~s many ~s the number of re~uested colors for each use.
Therefore, when the ~ deviees are prepared. three types o~ the LED devices should be assigned for optical three prim~ry coloxs. The LED devi~es should ~lso be as~igned to each type o~ light quantity cont~ol corre~ponding to the light mixin~ ratio~
Thus, there have been th~ pro~lems that the LE~
devices give the user~ trouble in appropriately maint~in~'ng the LED devices ~ b~ing classified cor~espondin~ to ea~h type of ~llmi~e.~cent color when they are manufactured and put on sales. The~e is another problem that the ~on~entional devlces require a considerably l~r~e store house to keep them i.n type ~S uni~A. Furthermore, ~n maintaining the dis~lay devi~e ~ 03-07 16:36 FROM:~2J~ $~ J. P.9~42 2 1 7 1 ~4i'1 conta nin~ the LED de~c~s, the lumi~e~cent colors and light ~uantity are lncorrectly managed in the prooe~s of main~aining the display devicQ cont~lning the LED
devices when a new ~ED de~ce i~ 1e~ibly used dep~n~tng on the l~inescent light. Additionall~, troublesome operations are required to prevent the problems f~om occux~ing.
S~mrnary of the Inven~lon The present inventlon aims at solving the above list~d problems associated with the prior ~rt technologies~ According to the pre~ent inventio~, An LED devi~ is provided ~y ~ounting a l.~ esc~nt diode ~it~ln~ each o~ optical th~ee ~rimary colors on a substr~te. This re~ers to ~ v~ria~le color LED
device. Tho varia41e color LED device comprises a current control circuit ~or controlling correspon~n~
to each color an electric c~rrent to be ~acæed to each 1~ in~CcQnt diode provided on the s~ætrate.
Confl~ured ~ d~cri~ed above iæ the LE~ color control devi~e~
Thus, the varidble ~olor LE~ devica c~n emit ~ny colors by config~ring the LED color control device ~ith th~ luminesccnt diodo emittiny e~ch color of 2s op~ical throe primary colors on a single substrate, - 36-03-07 16: 36 FROM~ ~ Y$~ J~ P. 10~42 -2i 71~4~
~nd by controlling for e~ch color the ~lectric current to the l~-in~cent diode, Thus, the LED ~evice can ba us~d ~ ~ small-8ize lumlne~nt displ~y picture element for v~ri~u~ color dlsplay devices, si~nal devices, et~.
That lS, the following effects can be ob~ained a~cording to the variabl~ color LE~ dhvic~ and LE~
color control device of the present inve~tion. First, since all co~ors can ba emitted by on~ va~iable color LE~ device, a small-size luminescent ~i~pla~ picture ~lement can be realizod for use outdoors and indoors in various co~or displ~y devlce, si~nal device, eto., there~y obt~inl ng an improved display picture image as Compare~ with the combinatlon of 3 L~D devlces each emlttin~ ~ single color. Second, whe~ the v~ri~ble cDlor LE~ ~evice ls used as a lumlnescent signal devic~ ~mittin~ vari~tions of oolors, the r~umber of ~l~nal lamps can be 1 re~ardles~ of the number of colors to be freely switched, thereby allowing much freedom ln designln~ the 6i~nal lamp ~or it~ lo~ion and arr~n~ement. Third, since ~ single varlable color LED devlce can be used to emit all colors, lt does not require sep~r~tely storing fo~ eac~ color in manu~actuxin~ and ~ale~ proce~ses. ~ven if it is incorpor~ted into ~ di~pl~y device, eto., the LED
l6-03-07 16:~6 FRa~ 2J~ *~ P. 11/42 ~i71244 dcvlce at har~d does not ha~o to be used only ~or a ~pec;~ fled color, thereby removt n~ trouble in storin~
th~ devic~, savin~ sto~age space for the stook, simplifyinç~ th~ assembly l?roces~, and allowin~ easy 5 m~intenance.
~rief Description of the Drawings FIG. lA ls a top view o ~he ~onven~ivnal LED
FI~. lB show~ the cu~re~t con~rol ~ir~it of the LE~ dev~ce;
FI~. 2A iS a top view of the variable color LE~
device a~ording to the first e~boaimen~ of the ~rQsant inVention;
FIG. 2~ is a ~ide view of the variable colo~ LED
devioe acco~ding to ~he firs~ embodim~nt of th~
FIG. 2C lc ~ bottom vi~w ~f th~ ~ariable color LED
device ~cc~rding t~ the ~irst embodiment ~f the 20 pr~sent in~entior~, FIG. 3 shows the variable color LE~ device and the current control circuit for controlling cu~rent of the ~evice accor~lng ~o the ~rst embodiment of ~he pre~nt in~ention;
~5 F~G. 4A ls a top view of the varlable color LED
36-03-07 16:37 FROM:~2~1"1`7*.~ ? ~ P.lZ~az device according to the second e~bodiment;
FIG. 4a s~ows the cirouit of the vaxiable cclo~
LED ~evice and c~rrent control circuit;
FIG. 5A shows the variable color LED device and current control circuit for controllin~ the c~rr~nt of the devlce according to the thtrd embodiment;
FIG. 5~ shows the vari~ble color LE~ device and GUrrent control circult for controlling the current of the device acco~ding to the fourth em~odi~lent;
FIG. 6 shows the variable color LED device and current control ci~cuit ~or controlling tha c~rrent of the device accordin~ ~o the ~i~th embodiment;
FIG, 7~ shows the variable color LE~ devic~ and current control clr~u$t fo~ cont~ollin~ the curren~
of the devi~ according to th~ si~th embodiment;
FIG. 7B shows the varia~l~ color LED device and curre~t ~ontrol circ~it for controll.in~ the current of the devtce accordin~ to the sev~nth ~mbodiment, FIG. 8 shows the variable color ~E~ de~ice configur~d to omit light in various colors limited ~y the seventh embodiment of the present invention: and FIG. 9 s~ows an e~ampl~ o~ the àpplication of th~
var$able color LED ~evice acco~aing to the preQ~nt invention to ~ si~nal lamp.
~6-0~-07 16:37 FROrl~ 4~ P.1~42 DescriptiOn c t~e Freferred r bo~ s The embodiment accordin~ to the pre~ent in~ention is desc~ibed below by referrin~ to the ~tt~hed drawlngs. FlG. ~A 18 the top view o~ the variable color LE~ device acco~ding to the first e~bodi~,ent of the present inventlon; FIG. 2~ is the ælde view of the devicéi ~nd FIG. 2C is the bottcm view of the device.
As shown in FIGs. 2A throll~h 2¢, ~ v~riqble c:ol~r 10 L~ device lO comprises ~ circular sub~trate 12 on a body 11. On the substrate 1~, three i~ in~Scent diodes R, ~, and ~ are mou~ted. A protective covex 13 covers the su~s~rate 12 ~nd ~ll these three luminescent di~des ~, G, and ~. Four tormlnal units 14~, 14g, 14b, and 14 are led from the bottom of the body 11.
The above described red luminescent dlode R em1~s red liyht. ~h~ gr~en luminescQnt diod~ G emits g~e~
light. The blu~ luminesoent diode ~ e~it~ ~lue l~ght.
The5e luminescent diodes R, G, and ~ ara arra~ged at equal intervals along the ~ircumference of the substrat~ 12. In ~IG. 2A, th~ luminescent diodes R, ~, and 3 a~e ax~ange~ s~ch tnat the cathode sides f~ce the center of the substrate 12 while the ~node si~es face ou~slde the substrate 12. ~he cathodes o~ the 96-03-07 16:~7 FRGI`1:~21~ $.j~4~. P.14~42 2~7124~
luminescent diodes R, G, and B are directly ~onne~ted to a common ~ermin~l unit 14 while the anodes ar~
separately connected to terminals 14r, 14g, and 14b through the current control circuit descrihed later.
~he protective cover 13 i~ made of ~ transmissible ~ateri~l. The tran_mission can b~ obt~ined throu~h a tran~parent or semltransparent material. However, it is desired that the ~at~r~al lS sem~transparent and photodlffu~ible so that the mixin~ of optical three primar~ color3 o~n be properly made.
FI~. 3 shows the connaction betw~n th~ vaxiable color LED device 10 and the current control circuit ~LED color control device). As ~hown in FIG. 3, tha c~thode of each of the luminescent diod~s R, G, zn~
~ is connect~d to the term~nal unit 14 while thQ anode of e~ch of the~ i3 connecte~ ~o the terminal units 14r, l~g, and 14~ through th~ vari~ble resiStan~es l~r, 16g, and 1~ ~f the c~rr~r.t control circuit 15.
The terminal unlts 14r, 14g, and 14b ~re ~onneoted to the plu~ terminal of the power source (not shown in th~ attachsd dxa~Jin3s~. ~he common terminql unit 14 i~ connected to the minus termin~l of the power souxce. The current that flows to th~ red luminescent dlode R aan ~e controlled by ad~usting the re~ist~nce v~lue of the v~riable ~esistan~e 16r. T~e size of th~
96-03-07 16: 37 FROM: ~2~ *.J~4~. P. 15~42 ;~ 2 ~ 4 current aontrols the amount of emisslon. Likewise, the a~ount of ~mission ~rom the lumine~cent diode G
can be controlled by adjustlng the resistance o~ the v~riable resist~nce l~g, ~nd the emount of emlsslon from the luminescent diode ~ ca~ be controlled by adjus~in~ the resistance of the v~iable resi~t~nce 16~.
The va~i~ble resista~ces 16r, 16g, ~nd l~b of the current control ci~c~it 15 axe not show~ in the atta~d drawi~gs. They can be pxovided in the body 11 shown in FIG. 2B, and their vaxiable re6i~tance units are interlocked with a sm~ orew th~t o~n ~e tuxned optional d~g~es ~lockwise or ~oun~Qrclockwiæe using ~ driver, etc. externally. Thus, the ~oltage ~cu~rent) of ~he three luminescent diodes R, ~, and ~ for op~ical three primary colors can be f~eely controlled. That i~, th~ quantity of' ligh~ o-f the 11 iney~nt dio~es R, G, or ~ can be optionally cont~olled whi~e tho ~E~ deYice is powered~ ~hus, the desired ll~r1nP-qcent color can be optionally ~et while usin~ the driver ~nd w~tching the en~ire lumiAescent color.
Since the variable color LED device 10 of t~e present invention ls prov~ded wlth the ll-m~n~ent diodes R, G, and a emitting optic~l three primAry 96-03-07 16:38 FRO1~ 2~" I`'Y$~ 2 i 7 l ~ ~ ~ P 16~42 colors, the varl~le color ~ED dev~ce c~n emit any tone of ~olor by ~x~ n~ the there colors.
For ~xa~ple, ~hen red is req~i~ed entir~ly, th~
resistan~e value o~ variab~e ~esistan~e 16r is de~eased to power o~ly t~e red l~minescent diode R, ~he reslstance values o~ ot~er variable re6i~tances 16~ and 16b ~re in~eased to the ~xi~u~ values to power off the lumlnescent dlodes B and G. When green is r~quired entirely, only th~ green luminescen~ diode G is powered whlle the lumine~cent diode~ R and ~ are powe~ed off. Like~se, when blue is requir~d entirely, only th~ blue lumine~oQnt diode ~ i~ powered while othe~ luminescent diodes R and ~ are p~wered of~. When ~he vari~ble col~r LED device tries to emit 15 any o~ the other aolors, the resistance value of each o~ ~he variabl~ re~i~tanoes 16r, 16g, and 16b is adjusted to appropri~tely control the amount of the electric c~rrent flowin~ to the l~min~ent diod~ R, G, or ~ sa that opti~ three prim~y ~o7ors are appropriately mixed to obtai~ a deslred color.
Each of the variable resistances are not provlded in the body 11, but ~an be mounted in ~n external perlpheral dev~oe. For example, the te~minal ur.i~s 14r, 14g, 1~, ~nd 14 ~re formed not as a flexib}e m~tal l~ad1 n~ llne but as a hard metal plug te~ lnæl 96-~3-07 16:38 FRO11:~ $~:J"4:J. 2 1 7 ~ ~4~ P.17/42 unit to real ize the simllar result b~ setting a varlable ~esi~tance ~etw~en th~ lnput terminal unit and output te~ l unit of the 40cket coupled to the plug terminal units. In this case, the resistance value ean be easily set if the va~iable re~istance ~s llnearly mounted ~long the ~xi~ of the sock~ with th6 ~o~ket shAped longer ~t it9 re~ por~ion. The resi~t~nc~ value can also be set easily ~y leading ~rom the side of the socke~ th~ leadlng li~e con~eo~in~ th~ socket to the pow~x s4urce, and by providing the ~etting unit of the ~ariable resistance with the top o~ a screw arran~ed at the rear portion ~f the soc~et. That ls, the socket can be optionally shaped as long ~s the v~ri~ble resi~t~nce can be properly set.
I~ a current control circuit is provided inside or outside the a~ove described sock~t or the vari~ble colo~ LED de~ioe, and lf the ~urrent control circuit is controlled by the displ~y oontrol cir~uit acco~din~
to a~ image signal, then the ~ariable colo~ ~ED device can also be used as a display pictuxe element of a dyn~mi~ ima~e~ The control b~ the di~play ~ontrol circuit can be made by pre~arin~ a look-up t~blo indiçating the relatio~ship between the intensity ~i~nal of the imags signal and ~ach va~ieble '96-03-07 16:38 FROM:~r2~ *.~ . P.18/42 21 11~
~e6i~ta~e of the curra~t con~rol ~irc~it ~rough which the di~pl~y picture element (varlable color LED
device) emit~ ht (colors~. Using tne lookup table, an im~ge sign~ n ~e converted in~o a variable resistanca control si~nal.
Thus, a luminescent pictu~e elemen~ th~t e~its various colors on a single ~ devi~e can be configured ac~ording to the present invention. The size o~ the emi~ting sur~ace of the ~E~ device is ~me millimeters long and is ver~ small. Therefore, very precise i~age c~n b~ o~tain~d wh~n th~ device is ~sed as a display pi~ture element of an outdoor display devica. It i~ obviou~ that a pr~Gise ima~e c~n be obtained when the device is used as a display lS picture element of an indoor displa~ device.
In the ~bove describe~ embodimen~, a total of 3 luminescent diodes, each o~ which is used to emit one of opti~al three prim~ry colors, are provided i~ a single ~ED device. ~wo lu~in~schnt diod~s ccn ~lso be pro~ided for each of opt~cal three primary colors.
Thls a~lication is described b~low ~s the s~cond e.. b~ nt of the present inventio~.
FI~. 4A and 4~ ~ho~ the se~ond embodiment in which two lumlnescent diodes are provided for ea~h of optical t~ree primary colors. FIG. 4A is a top ~iew 96-03-07 16:38 FRO~ 2J~ *~ P. l9i`~Z
~ 1 7 1 ~ Ll 41 of the varia~le c~lor LED de~ice. FIG. 4B sho~ ~h~
vaxi~ble color LE~ devica and th~ curren~ cont~ol circ~it for con~olling the aurrent~ As shown in FIG.
4A, a ~ariAble ~olor LED devic~ 20 i~ pr~vided with a tot~l o six luminescent diodes, that is, two red luminescent diodes Rl and R2, two green lu~ine~cent diodes Gl and G2, ~nd ~wc bl~e lumine~cent diode~
and B2 o~ a sub~trate 22.
Th~ variable color LE~ device 20 shown in FIG. 4A
ls similar, a~art from the n~m~r of terminal units, in sh~pe ~o the body 11 of the variable c~lor LE~
d~vi~e 10 shown in FIGs. 2B and 2C as viewed from the side and bottom (although the si~llarity i5 not shown in the ~tta~hed drawings). Th~ variab}e color L~
device 20 is sm~ller than 5mm in ~ia~eta~ of the emitting suI ~2c~, 4nd i~ very small and covered with a p~otective tr~nsmisslon cover at i~s top.
In thia case, the luminescent diodes Rl, R2, Gl, G~, B1, a~d B~ are arran~ed at equal intervals along the circumferen~e of the su~st~ate ~2. As s~own i~
FIG. 4B, the anodes of the lumlnescent diodes Rl, R2, Gl, G2, ~1, and B2 are connected ~o the terminal u~it 14 whlle the cathodes of them are connected to t~e te~min~l unit~ 14r-1, 14r-2, 14g-1, 14g-2, 14b-1, and l~b-2 throu~h the variable resistances 16r-1, 16r-2, 96-E~3-0~ 16:38 FR011:~2~ $;1~ p.Z0/4~
16~-l, 16g-2, 16b-1, and 16b-2 of a current control cixcuit 25. That ls, a total of 7 te.rminal units ax~
l~d from th~ bottom o the b~dy.
In the case according to the second embodiment, th~ tarm~nal un7ts 14r-l, 14r-2, 14g-l, l4g-2, 14b-l, and 14b-2 are connected to the pl~5 term~nal Gf the po~er source while the ~om~on terminal unit 14 is connected to the ~inus te~m~ nal of tne power source.
The amount of emie~ion from t~e r~d lu~in~cent diod~
Rl an~ R~ is a~usted b~ controlling the current -~ith th~ resistanc~ ~alu~s o~ th~ Ya~iabl~ re~i~tances 16r-l and 16r-2 properly adjusted. Likewise, the amount of ~ission from the green lu~inescent diodes Gl ~nd G2 is adJusted by controll~ng the resistan~e valu~s of the v~riable resistances 16~-1 and 16g-2. The amou~t of emlssion frPm the blue luminescent diodes Bl an~ ~2 ~s adjusted by controllin~ the resist~nce ~alues o the variable reslstances 16b-1 and 16b-2.
Alao in the second embodiment, ~s in the first ~0 embodi~ent, each o~ t~e variable resistances 16r-1 thxough 16b-1 of the c~r~ent contxol clxcuit 25 can be provided in the body unit, and sm~ll screws lntexlockln~ with the vaxlable units of the vaxlable resist~ce~ ~re turned using a driver, etc. to adjust the xesis~nce v~lues. Othexwise, the termlnal units '96-0:3-07 16:39 FRO1~ 2~ *~ Gj~ P.Z1~42 ~1 7 l ~44 14~, 14g, 14b, ~nd 14 are formed BS a hard metal plug term$nal unlt to realize the simllar result by setting va~iable xesistdnces 16r-1 throu~h 16b-2 batwe~n th~
input termin~l unit and output termir.~l unit of ~he S socket coupled to the plug terminal u~its. In thi~
ca~e, each of the varlable resistances 16r-1 through 16b-2 c~n be controlled using a lookup t~ble throu~h an external display cont~o~ clrcuit so that the devi~e can be used as ~ display picture element ~f a dyn~mic image.
Since the second em~odiment is tw~ time~ as many as the abo~e desc~ibed irst embodiment in n~mbe~ of lumines~en~ diodes, the amount of e~isslon from the luminescent diode is two tim~s ~s ~uch from the entire ~ariable color LED device 20. Therefore, even if the devi~e is used outdoors as a display picture el~ment of the di~play device, ~uffi~ient amount ~f emission (intenslty) can be obtained, thereb~ form~ng a precise i~nage .
According to the abDve de~ribed embo~ nt, the variable resistan~e and terminal on the ~no~e si~e are arranged such that t~ey co~respcnds one by one ta each lumine~cent ~lode. However, the axrangement and connection of the variable xesi~tanc~ and terminal on ~5 the anode side to the l~inescent diode are not 96-03-07 16::39 FROM:~2h" ~ ~*.~ . P.2Z/42 ~1712~4 limitcd to this embodiment. ~escribed ~elow as other embodi~ent6 are the arran~ment and connectton of the v~riable resist~n~e and terminal on the ~node side to the lllmine~ent diode.
FIG. SA shows the variable color LED device and the current control circuit for controlling the current according to the third embodiment. As in th~
second ~mbodiment, a va~iable color LE~ devlce 30 is provided with ~ luminescent diodes, ~nd their cathodes are connected to t~e common ~erminal 14. Ac~ordin~
to the emb~diment, on the ~node sides, l~mine~aent diodes Rl and R2 are conne~ted in parallel, ~ ine..scent diodes Gl ~nd G2 a~e connec~ed in parallel, and luminescent diodes Bl ~nd 132 are connected in parallel to the output terminals o the vari~ble re~i~tance~ 36r, 36~, and 36b respectively for each c~lor. The input terminal~ of the varia~le resistan~es 36r, 36g, and 36~ ~re connected to the terminals 34r, 34g, and 34~. This is the only di~ere~ce ~f th~ third embodi~ent fr~m th~ ~e~ond e~ho~ i m~nt . That is, ac~ording to the third embo~;~ent, two l~inesc~nt diodec ~re p~ovided for each color of opt~cal three p~imary colors. ~he curxent fo~ th~ luminescent diodes can be cont~olled ~S not individu~lly a~ in the secand embo~i ~n~, but 96-03-07 16:39 FROI~ 2t~ *,~ P.2~/42 ~171 ~4 collecti~el~ controlled fcr a p~ir of l~mlne5cent diodes fo~ the same col~r. In tht~ ca~e, when the variable color L~D device 30 is combined with ~
current control ctr~uit 3S, a total of ~ tGrminal unlt~ axe led.
FIG. 5B shows the variable color LED d~vic~ ~nd the ~urrent control ~ir~uit for controlling the ~urrent acco~dln~ to the fourth embodime~t. In this am~odiment, a vari~ color L~ device 40 is provided, as ln the s~oond dnd third embodiments, tha luminescen~ diodes Rl, ~2, Gl, G2, ~1, and ~2 with a pair o~ the diodes mount~d for each of optical three p~imary colors. ~owever, açcording to the fourth ~mbodiment, the luminescent diodes are ~ol~neGte~ in series for each color, end ~ p~ir of lumine~ce~t diodes connected in s~ries for ~ch ~olor (red luminescent dio~es RL an~ R2, green luminescent diodes G1 and ¢2; and ~lu~ min~ont diod~s ~1 and B2) ~re respectively connected to the output tel inals of the v~riable rQsistances 46r, 46g, and 46b respectively.
The input ter~inals of the va~iable resistances 46r, 46~, and 46~ are cor~ecte~ to the te~in~l units ~
44g, and 44b respectively. This is the dif~erence b~tween the third ~nd fourth embodiments, In the fouxth embodiment, a total of ~our terminal units a~e '96-03-07 16:39 FROM:~2J~ *.~ - P.24~'4Z
~712~4 led with the coni~ura~10n o~ the variable color LED
device 40 ccmbinad with ~he ~urrent control ~irauit 45.
The vari~ble color L~D device ~nd current control 5 circuit can be conflgured a6 ~ot being ~ombined with e~ch other in the third ~nd fourth embodiments. ~hat is, the current control clrcuit can be connected a~
an external device to the variable eolor LED device through a so~ket, etc. Also the variable resistanc~
can be controlled on the ~ispl~y in real time ~ccor~ing to the l~age sl~nal uslng the ~is~l~y control device ~nd lookup ta~le.
FIG. 6 shows the variable colo~ L~D device according to the fi$th embodiment ~nd tne current lS control circuit for controlling the current. FIG. 7A
show~ th~ vari~ble color LED device accordin~ to the SiXth embodiment and the curre~t control oircuit for controlling the current. FI~. 7~ ~hows the variable oolor LED devioe acc4rdin~ to th~ seventh ~-~o~ent and t~e current ~ontrol circuit for cantrollin~ the current.
A ~ariable color LED devi~e 50 ~hown in FIG. 6 accordtn~ to the fifth emb~di~ent is provided with tot~l of nine luminescent diode~, that is, three red .25 l~ ;nR.qc~nt dioda~ Rl, R2, and R3; three green 96-03-071640 FROM~2~ *.j~4~ 4 4 P.Z5~2 luminescent diodes ~ 2, and G3; ~n~ thre~ blue luminescent diodes ~ 2, an~ ~3 on the su~strate.
The variable color LE~ dovice 50 shown in FIG. 6 is also similar in shapQ, apart from the number of tenminal unlts, to the body 11 of the variable ~olor LED device iO shown in F~Gs. 2~ and 2C ~s bein~ viewed frorn the side and bottom. However, the similari~y i~3 not shown in the ~tached d~win~s. The variable color LED devica 50 can dl~o b~ ~ormed about 7 or ~
mm in diameter of ~he lumineccent surrace, and ~he de~ice ls covered with a transmissible protective cover.
The lu~inescent diodes R1, R2, ..., ~2, ~nd L3 are arranged along the circumference o the substrate ~t lS e~uAl intervals. The anodes are conne~te~ to ~he common terminal unit 14 while ~he oathod~s ~re conneoted to th~ t~rminal ~ni~s 14r-l, 14r-2, 14g-1, 14~-2, 14b-1, and 14b-2 thrcugh the va~iabl~
resl~ta~ces 5~r-l, 56r-2, 56r-~, 56g-l, 56g-2, 56g-3, 56b-1, 56b-2, and 56b-3 of a current control cir~uit 55. That is, if the v~ria~le color L~D d~vice 50 is ~.bineA with the cur~ent cont~ol circ~it 55, ~ total of 10 terminal ùnits ~r~ le~ fro~ the bottom o~ the body.
In this ~xample, te~min~l unlts 54r-1 through 54b-96-03~7 16:40 FROM:~2~ *.:J~4~ 44 P.~6/12 3 ~re con~ect~d to the plu~ terminal of t~e power so~rce ( not shown in th~ attached drawin~s ), an-l ~he -_ terminal unit 14 i~ connected to the minus terminal o~ the powex source. The amc~unt o~ emission 5 from the red lumine~cent dlodes Rl through R3 is controlled based on the resistance values of the variable resistances 56~ hrough 5~r-3. ~he a~oun~
of emission from the green l~ ne~cent diod~s ~1 ~hrough ~3 i6 controlled ~sed on the resistance valu~s of the ~ariable resistances ~g-l thro~h 5~g-3 T~e amount of emission irom the ~lue luminescent diodes B1 throu~h B3 is controll~d basad on the resistanc~ values of the variable resistances 56b-~through 56g-3.
A vari~ble aolor ~ED devi~e 60 ~ccording to ~he sixth e~bodiment shown in F~. '7~ is, as ln the fifth e~bodim~n~, is provided wit~ ~ total Of 9 lum1nescent diodes. The cathodes are connected to the ~ommon terminal unit 14 while the anodes of th~ three ~0 lumine~cent diodes ~or each color ~re connected to the outS;~ut tl3nninals of variable resist~nces 66r, 66g, and 66b in series. rrhe ln~u~ te~ i n~ of the va~iable resist~nces 66r, 66g, and 66~ are conn~cted to t~rminals 64r, 64g, and 64b. Thi~ is the difference 2S ~etween the fifth ~nd sixth embodlments. Th~
~-03-~7 16:40 FRO~ Y*,~~ 44 P Z7/42 according to the sixth embodimcnt, three l~mines~ent diode~ ar~ pr~vided or e~¢h o~ opt~cal three prlmary colors. The current ~hat flows to the luminescent diodes is not individually controlled as in the fifth S ~ ~o~i ent, ~ut a set of three luminescent diodes is aollectively controlled for the same lu~inescent color~ If the varlable color LED device 60 is ~n~ined with a cu~re~t control cir~uit 65, a total o~ ~ t~xminal unlt6 are led f~om the device.
A v~riable color L~ device 70 according to the ~eventh embodiment ~hown in FIG. 7~ is the s~me as the devic~ according to the fifth and sixth embodiments in that the three ra~ lumine~cent diGd~s Rl, R~, and ~, thr~e green luminesçent dio~es Gl, ~2, and G3, ~nd 15 ~hree blue luminescent diodes B1, ~2, a~d ~3 a~e provi~ed for respective ~ol~rs of optical thre~
prim~ry colors. Howe~er, according to the sevçnth ~mbodiment, t~ree luminescent ~iodes are co~ne~ted in series for each color, and a set of three lumineacent diodes con~ected in series (red l-~m1ne6cent diode-q ~l, R2, ~nd R3, ~reen lumine3c~nt diodes Gl, G2, ~nd G3;
and blue l~minP~ent diodes Bl, B~, and B3) ar~
aonnecte~ to the output ~erm~ ,C of variable resi~t~ncP~ 76r, 76~, and '7~ re~pectively. The i~put t~ ;~Als of the vari~b~e res~stAnC~ 7~r, 76g, and ~6-0~3-07 16:4E~ FRO1~ 2J~ *.:~4:~. P.28~42 2 1 1 1 ~4~
76b ar~ connec~ed t4 te~minal units 74rr 74y, ~nd 74b.
This i~ the differ~noe between the fifth and six~h embodiments. In th~ 5 embodiment, if the variable color LED device 70 is combined with a current ~ontrol circuit 75, a total of 4 termlnal units ~re led rom the devi~e.
In the fifth, sixth, an~ seventh embodiments, the variable color LE~ dovi~ is not combined with the current control Gircuit, ~u~ the current control circuit can be co~ne~t~d as an e~tern~l devioe t~ the variable color LED device through a socket, et~. The variable ~sistance c~n be controlled on the display in real time acco~ding to the lma~e signal using the display control device And loo~up ~a~le.
FIG. 8 sho~s ~n e~ample of the vari~bl~ color LE~
de~lce configu~ed ~o emit various lumi~es~ent colors limited by the seventh embodim~nt. Tho v~riable color LED device shown in FI~. 8 is provided with eight chip ~esl~tances 87 having res~ective r~sis~an~e values, two red lumi~sc~nt diodes R, fo~r green luminesc~nt diodes G, and two blue lu~inescent diodes ~ on a sub-~trate 82. Thus, the luminP~cent diodes do not helve to be equal in ~ ~bsr for ~3~ch color. In other w~rds, sin~e the ~uantit~ o~ ht of e~ch of the ~5 optical three prlmar~ ~olor~ ifi prede~ermined ~o emit 96-03-0'7 16:41 FRO1~ 2Jl~ $.~ . 2 1 7 1 ;~ P.29~4Z
a requested colo~, the number o the 1~1 ;n~cent dlodes can ba deteL ;~e~ accordin~ t~ the pre~etermined quantit~ of llght ~or ea~h of the optical three pr~mary colors. Furthermo~e, appropriately ~witchin~ the ~onnect~ons to the chip resistances enabl~fi a desired ~olor to be emitted from ~mong limited v~riations of colors. If ~ tri~ming reslstance (v~riably set ~s a ~esis~nce value by tri~ing ~ resis~ance chlp uslng, for example, a laser light) is used as a chip resist~ce for controlling the current of the ~arLable color LE~ d~vice, th~
re istance ~alue c~n be optionslly v~ried.
As described above, any num~er of l~minescent diodes c~n be used for ea~h of optical three prlm3ry colors in the variable color LED device o~ the pre~ent in~ention. It is obviou~ that the larser ~he number of the l- ~nescent diodes is, the larg~r guantity of light is emitte~. The eonfi~uratio~ of the ~urrent con~rol circuit and the connection to the c~rrent control circuit c~n be cont~olled depending on the confi~uratlon in ~aeh a~bodi~ent. Addition~lly, sin~e a lig~t of ~ny color can be emitted on a sln~le varlable color ~ED devi~e, the funct~ ons ~f plu~lity of ~onventional em$~tin~ devices can be performed by ~ single emitting device (~risble color 96-03~7 16:41 FR01~ $.j~. P.3E~/4Z
FI~. 9 sho~s an applic~tion of the variqble ~o]ar LED device fox uRe in th~ traffic signal lamp~. It shows a new variable color LE~ device according to ~he present ~ention ~elow a traffic ~ignAl ld~p shown just $or comparison. The traffic signal lamp shown in FIG. g comprise~ a red signal lamp 84; ~ yellow signal lamp 85. and a ~reen signal lamp 85. It functions ~9 traffic ~i~nal lamps by ~eq~entially e~ltting ~he thr~e colors. That i5, three emitting devices are usea to exclusively e~i~ a specif iod color. On tho other h~nd, using the varicble ~lor LED device according to the present i~vention, the system comprises only one signal lamp 87. qlhe eu~re~t control circuit controls ~or each color the electric current to ~he luminescen~ diode. When the varioble color LED devlce lndlcate~ red, ! t emits r~d light.
~Ih~n th~ variable ~olor LED dev~ce indic~te~ yellow, it emit~ yellow li s~ht . When thQ variable color I,EI~
20 dev~ ce indicates ~reen, it emits gre~rl light .