Abstract:
An illumination system for motor vehicles, which contains both parking/daytime running lights of one color and turn signal lights of another color. The invention detects whether parking lights are being displayed and, if so, flashes a parking light alternately with its adjacent turn signal light, rather than constantly illuminating the parking light while flashing the adjacent turn signal light.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a light and/or signaling device for motor vehicles and, more particularly, to a lighting and/or signaling device adapted to control the activation of parking/DRL light and a proximately located turn signal light so that the turn signal light is not diminished by the light from the parking/DRL light. 
     2. Description of the Related Art 
     In some vehicle markets, a white park lamp is often combined with an amber front turn signal lamp. This is acceptable because the park lamp is allowed to turn off when the front turn signal is activated. The problem comes about when this same configuration is proposed for the North American market. In North America, once the park lamp is on, it must remain on by regulation. So in the case where a white park lamp and an amber front turn lamp is optically combined, when the front turn lamp turns on, the amber color is diminished due to the white park lamp. This results in a configuration in which the perception is that the park lamp remains on throughout the activation of the front turn, but the turn lamp amber color may not appear as purely amber. 
     One solution to this problem was that the park lamp was converted to an amber park lamp or the white park lamp was separated from the front turn lamp for the North American market. 
       FIG. 1  is a front view of a generic vehicle  3 . The vehicle  3  is equipped with parking lights  4 , which are also used as daytime running lights (DRL). The parking or DRL lights  4  function primarily to make the vehicle  3  more visible to third parties, such as the drivers of other vehicles, during the daytime when functioning as a DRL, and at night when functioning as a parking light and the DRL is a higher intensity function than the parking light function. In other words, it should be understood that the park function is different from the DRL function even though they are they same lamp. 
     The vehicle  3  is also equipped with headlights  5 , which serve a different primary function, namely, to illuminate external objects at night, and make them visible to the person driving vehicle  3 . The headlights  5  generally consume more power than do the parking or DRL lights  4 . The vehicle  3  is further equipped with turn signals  6 , which indicate a direction of an upcoming turn by the vehicle  3 . 
     The parking lights  4  are commonly white in color, and they are often illuminated whenever the vehicle  3  is operational. The turn signals  6  are commonly amber in color, and one of them is illuminated by flashing during a turn, but generally not at other times when the vehicle  3  is being driven. 
     This particular combination of white parking lights  4  with amber turn signals  6 , together with the constant illumination of the white parking lights  4 , can affect the visibility of the turn signals  6 . 
     That is, the white light emitted by a parking light  4 , which is adjacent to an amber turn signal  6 , can dilute, as it were, the light of the amber turn signal  6 . This dilution can make the amber turn signal  6  less visible. By analogy, a street lamp in a parking lot will appear very bright at midnight, when it is the only light source present. However, at noon the street light appears far less bright because another light source is present, namely, the sun, which dilutes the light of the street lamp. It may be thought that the dilution of the turn signal can be reduced by extinguishing the white parking lights  4  while the amber turn signal  6  operates. However, government regulations in some localities prohibit this. 
     In addition, the arrangement of  FIG. 1  requires equipment which can be viewed as complex. As the exploded view or inset  7  in  FIG. 2  shows, each parking or DRL lights  4  requires a housing  4 B, a lens  4 C, and a light source  4 D, such as a light-emitting diode, or LED. Similarly, each turn signal  6  can require its own housing  6 B, its own lens  6 C, and its own light source  6 D. Additional equipment to that shown in the simplification of  FIG. 2  can also be required. All these items add cost and logistical complexity to the manufacturing and assembly of the vehicle  3 . 
     What is needed, therefore, is a signaling and/or lighting system and method that overcomes one or more of the problems in the prior art. 
     SUMMARY OF THE INVENTION 
     One object of one embodiment of the invention is to provide an improved lighting and/or signaling system for vehicles. 
     A further object of one embodiment of the invention is to provide an improved system of turn signals for vehicles. 
     Still another object is to provide a system and method that optically combines a white park lamp and an amber turn signal lamp in a manner that light from the amber turn signal lamp is not diminished due to the white park lamp. 
     In one form of one embodiment of the invention, when a driver issues a turn signal, but when parking lights are illuminated, the invention creates a flashing signal comprising a sequence of flashes of white light are interspersed with, or alternate with, a sequence of flashes of amber light, such as white-amber-white-amber etc. 
     This is accomplished in one aspect of one embodiment of the invention by utilizing two adjacent lights in a particular manner. The adjacent lights are colored white and amber. The procedure can be divided into two steps. In step  1 , the invention illuminates the amber light and extinguishes the white light. In step  2 , the invention illuminates the white light and extinguishes the amber light. Then steps  1  and  2  are repeated. 
     In one aspect, one embodiment of the invention comprises a lighting and/or signaling device for a motor vehicle, comprising at least one first light source for producing a first colored light and at least one second light source, a control system which energizes the at least one second light source to produce a blinking or pulsing light in response to a switch or lever being actuated, the blinking or pulsing light having a light on period and a light off period, and energizes the at least one first light source to produce the first colored light during the light off period and does not energize the at least one first light source. 
     In another aspect, another embodiment of the invention comprises a lighting and/or signaling device for a motor vehicle having a turn signal actuator, operable by a driver of the vehicle, to generate a turn indicator light, said lighting and/or signaling device comprising a plurality of front parking or DRL lights, each of which (1) emits a first colored light, and (2) is located adjacent a respective turn signal light that emits said turn indicator light of a second color that is different from said first colored light, comprising a control system which causes said turn signal light to flash alternately with its adjacent parking or DRL light. 
     In still another aspect, another embodiment of the invention comprises a lighting and/or signaling device for a motor vehicle which has a left parking or DRL light, a right parking or DRL light, a left turn signal light associated with said left parking or DRL light and a right turn signal light associated with said right parking or DRL light, said lighting and/or signaling device comprising a first signal line which receives a first actuation signal for both right and left parking or DRL lights, a second signal line which receives a second actuation signal for at least one of the right or left turn signal lights, a control which, in response to the first and second actuation signals, causes either (i) said left parking or DRL light and said left turn signal light to flash, but alternately with each other, or (II) said right parking or DRL light and said right turn signal to flash, but alternately with each other. 
     In yet another aspect, another embodiment of the invention comprises a lighting and/or signaling system for a motor vehicle comprising a) a parking or DRL light source and a turning signal light source on left and right sides of the motor vehicle, b) a first switch (S 1 ) selectively operable by a driver of the motor vehicle to generate either a right turn signal or a left turn signal, c) a control which i) steadily illuminates said parking or DRL light source and does not illuminate said turning signal light source when no turn signal is requested, ii) does not illuminate said parking or DRL light source and alternately illuminates said turning signal light source when said parking or DRL light source is activated and said driver has activated said first switch (S 1 ). 
     In still another aspect, another embodiment of the invention comprises a lighting and/or signaling device for a motor vehicle, operated by a driver, which contains a left front parking light, a right front parking light, a left front turn signal light, and a right front turn signal light, said lighting and/or signaling device comprising a) a switch by which the driver can use to selectively issue a request for a left turn signal or a right turn signal, b) a control which i) responds to the request for the left turn signal by detecting whether the parking lights are illuminated and A) if not, flashing the left front turn signal light and B) if so, alternately flashing the left front parking light with the left front turn signal light, while maintaining the right front parking light steadily illuminated, and ii) responds to the request for the right turn signal by detecting whether the parking lights are illuminated and, A) if not, flashing the right front turn signal light and B) if so, alternately flashing the right front parking light with the right front turn signal light, while maintaining the left front parking light steadily illuminated. 
     In still another aspect, another embodiment of the invention comprises a lighting and/or signaling circuit for a motor vehicle, operated by a driver, which contains (1) a left front parking light, (2) a right front parking light, (3) a left front turn signal light, and (4) a right front turn signal light, said lighting and/or signaling circuit comprising a) a first switch (S 1 L), b) an oscillator (V 1 L) which produces a pulse train comprising voltage pulses, c) a second switch (S 2 L) which receives the pulse train, d) a third switch (S 2 R) which receives the pulse train, e) a first transistor (Q 1 L) which is induced by closure of the first switch (S 1 L) to actuate the left front parking light, f) a second transistor (Q 1 R) which is induced by closure of the first switch (S 1 L) to actuate the right front parking light, g) a third transistor (Q 4 L) which is induced by the pulse train when passed by closure of the second switch (S 2 L) to periodically actuate the left front turn signal light, h) a fourth transistor (Q 4 R) which is induced by the pulse train when assed by closure of the third switch (S 2 R) to periodically actuate the right front turn signal light, i) a fourth transistor (Q 2 L) which is actuated by the pulse train when passed by closure of the second switch (S 2 L), which shuts off the first transistor (Q 1 L) when the left front turn signal is actuated, and j) a fifth transistor (Q 2 R) which is actuated by the pulse train when passed by closure of the third switch (S 2 R), which shuts off the second transistor (Q 1 R) when the right front turn signal is actuated. 
     This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the following bullet list and the claims. The lighting and/or signaling device wherein said first colored light is white and said at least one second light source is amber. 
     The lighting and/or signaling device wherein said at least one first light source and said at least one second light source both comprise at least one semiconductor light source. 
     The lighting and/or signaling device wherein said at least one first light source comprises a plurality of white parking or DRL light sources at a front of the vehicle, and a plurality of amber light sources, at least one of which is one adjacent each of said plurality of white parking or DRL light sources, and said visual signal is produced by alternately flashing one of said parking or DRL light sources with its adjacent amber light source. 
     The lighting and/or signaling device wherein said first light source does not produce said first light when said second light sources produces a second color and said second light source does not produce said second light when said first light source produces said first color. 
     The lighting and/or signaling device wherein each of said plurality of said front parking or DRL light sources comprises at least one LED that generates a white light, and said turn signal light being an LED that generates an amber light, said control system alternately flashing said first colored light from said parking or DRL light source and its adjacent turn indicator light. 
     The lighting and/or signaling device wherein said parking or DRL light source does not produce said parking or DRL light when said turn signal light produces said turn indicator light and said turn signal light does not produce said turn indicator light when said parking or DRL light source produces said first colored light. 
     The lighting and/or signaling device in which, when both said first and second actuation signals are present the right and left parking or DRL lights are always illuminated, but either the right or left parking or DRL light is dark when its adjacent right or left turn signal light, respectively, is illuminated. 
     The lighting and/or signaling circuit in which the left front turn signal light flashes alternately with the left front parking light when second switch (S 2 L) is closed when the parking lights are illuminated. 
     The lighting and/or signaling circuit in which the right front turn signal light flashes alternately with the right front parking light when third switch (S 2 R) is closed when the parking lights are illuminated. 
     The lighting and/or signaling circuit in which the right front parking light remains steadily illuminated when the second switch (S 2 L) is closed when the parking lights are illuminated. 
     The lighting and/or signaling circuit in which the left front parking light remains steadily illuminated when the third switch (S 2 R) is closed when the parking lights are illuminated. 
     These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING FIGURES 
         FIG. 1  illustrates a generic vehicle of the prior art; 
         FIG. 2  illustrates schematically a prior art parking or daytime running lights and turn signal lights in exploded view of the vehicle shown in  FIG. 1 ; 
         FIGS. 3A, 3B, 3C, and 3D  illustrate a prior art sequence of flashing of lights of a prior art vehicle of  FIG. 1 ; 
         FIGS. 4A, 4B, 4C, and 4D  illustrates flashing of the lights under one embodiment of the invention; 
         FIGS. 5A, 5B, 5C, and 5D  illustrate the flashing of  FIG. 4  in isolation; 
         FIG. 6  illustrates one form of one embodiment of the invention in which DRL and turn signal light sources are contained within a single housing; 
         FIGS. 7A, 7B, 7C, 7D, and 7E  illustrate the flashing of the park and turn signal light sources contained within the single housing as in  FIG. 6 ; 
         FIG. 8  contains images A through D, which illustrate a sequence of flashing implemented by one form of the invention; 
         FIGS. 9A-13  illustrate an electronic circuit, in various conditions, which implements one form of the invention; 
         FIG. 14  illustrates how the circuits of  FIGS. 9A-13  control lights on both the left and right sides of a vehicle; 
         FIG. 15  is a simplified view of  FIG. 14  and compares it with the prior art; 
         FIGS. 16A and 16B  is a truth table and timing diagrams, respectively, illustrating operation of one form of the invention; and 
         FIG. 17  illustrates requirements of flashing times for turn signals in North America. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An operation of one type of a prior-art turn signal will first be described in order to emphasize benefits achieved by the invention. 
     In brief, in  FIG. 3B , a right-hand turn signal  6   a  flashes an amber light on and off while the two white parking or DRL lights  4  remain continuously illuminated. This event will be explained step-wise. In  FIG. 3A , the vehicle  3  displays white parking or DRL lights  4 , but no turn signal. In  FIG. 3B , the right-hand turn signal  6   a  is momentarily illuminated and emits the amber light. The dilution described earlier may occur at this time. 
     Then, in  FIG. 3C , the right-hand turn signal  6   a  temporarily goes dark between flashes. Next, in  FIG. 3D , the situation of  FIG. 3B  is repeated, wherein the right-hand turn signal  6   a  is again illuminated. The sequence of  FIGS. 3A through 3D  continues until the turn by the vehicle  3  is completed and the turn signal is cancelled. 
     In contrast, the embodiments described herein provide control of the parking and DRL lights and turn signal lights in various embodiments or environments, such as when the lights are housed in separate housings ( FIGS. 4A-4D ) or when they are housed in a common housing as illustrated in  FIGS. 6-9B  Both illustrative embodiments will now be described.  FIGS. 4A-4D  illustrate operation of one embodiment of the invention and shows right parking or DRL light sources  10  adapted to generate white light in a vehicle V which are clearly separate from right turn signal lamp or light source  12  which is adapted to generate amber light. It should be understood, however, that these colors could be different if desired. Left parking or DRL light sources  14  and left turn signal light sources  16  are also provided. In brief, in  FIG. 4B , when the turn signal or light source  12  is illuminated, it generates an amber color and the adjacent parking or DRL light source  10  does not generate the white light or different color. Then, when the amber turn signal or light source  12  is extinguished, the adjacent white parking or DRL light source  10  is re-illuminated. That is, the white parking or DRL light source  10  and the amber turn signal lamp or light source  12  are not illuminated together, but they alternate in white and amber emitting light, respectively. Thus, both the parking or DRL light source  10  and turn signal lamp or light source  12  flash, but alternating. The same functionality applies to the left-hand parking or DRL light source  14  and the left-hand turn signal lamp or light source  16 . 
     However, this particular flashing of both the amber turn signal lamp or light source  12  and the adjacent parking or DRL light source  10  only occurs when the parking or DRL light source  10  is illuminated and a turn signal request occurs at the same time. At other times, when the parking or DRL light source  10  is illuminated, but no turn signal request is issued, the white parking or DRL light source  10  remains continuously illuminated in the usual manner. Alternatively, if the parking or DRL light source  10  is off and a turn signal request is issued, the turn signal light source  12  flashes in the conventional manner. Again, the left-hand parking or DRL light source  14  and turn signal light source  16  operate similarly. 
     To repeat, in one form of one embodiment of the invention, the amber light generated by the turn signal light source  12  in  FIG. 3B  and its adjacent white parking or DRL light source  10  are caused to flash alternately. That is, when the turn signal light source  12  is on, the adjacent parking or DRL light source  10  is off. Conversely, when the turn signal light source  12  is off, the adjacent parking or DRL light source  10  is on. The sequence will be explained step-wise. 
     In  FIG. 4A , the parking or DRL light source  10  generates white light and the parking or DRL light source  10  is continuously illuminated during normal operation of the vehicle V. In  FIG. 4B , the right-hand turn signal light source  12  is momentarily illuminated when there is a call for a right-hand turn signal. At this time, one embodiment of the invention extinguishes or terminates the adjacent parking light, which is also located on the right-hand side of the vehicle V. Then, in  FIG. 4C , the amber light from the right-hand turn signal light source  12  is extinguished, as occurs during normal flashing of a turn signal, the right-hand parking or DRL light source  10  generates white light and becomes illuminated. Then, as in  FIG. 4D , when the right-hand turn signal light source  12  becomes illuminated again, as occurs during normal flashing, the amber light is generated, but the adjacent parking or DRL light source  10  is extinguished. The sequence of  FIGS. 4A through 4D  continues until the turn by the vehicle V is completed, and the turn signal is cancelled. The same sequence applies to the left-hand parking light or DRL light source  14  which generates white light and adjacent left-hand turn signal light source  16  which generates amber light. 
     It should be understood that during the sequence of  FIG. 4A-4D , the opposite side parking or DRL light source remains illuminated at all times. In the example, the left-hand parking or DRL light source  14  remains illuminated continuously, and its adjacent turn signal light source  16  ( FIGS. 4A-4D ) remains dark at all times during activation of the right hand turn signal. 
     This alternate illumination of (1) the right-hand turn signal  12  and (2) its adjacent parking or DRL light  10  reduces or eliminates the dilution described above. Further, this operation gives the appearance that the parking light signal  10  remains continuously illuminated during the operation of the turn signal  12 . 
       FIGS. 5A-5D  illustrate the sequence of  FIG. 4  in simpler terms using just the parking or DRL light sources  10  and turn signal light sources  12 . In  FIG. 5A , the turn signal light source  12  is off, and its adjacent parking or DRL light source  10  is on. In  FIG. 5B , the turn signal light source  12  is on in response to a driver actuating a turn signal level or switch (not shown) inside the vehicle V. Note that when the turn signal light source  12  is on, its adjacent parking or DRL light source  10  is off. In  FIG. 5C , the turn signal light source  12  is off, and the adjacent parking or DRL light source  10  is on. In  FIG. 5D , the turn signal light source  12  is on, and the adjacent parking or DRL light source  10  is off. This sequence continues until the turn signal is cancelled. 
     The previous embodiment was described using a conventional parking or DRL light and turn signal housings (i.e., one for each function).  FIGS. 6 and 7A-8  illustrate another form of an embodiment of the invention, wherein the parking light and turn signal light are not visibly separated and are housed in a common housing. A single lighting and/or signaling device  20  contains light sources  10  and  12  in the form of light-emitting diodes or LEDs  22  and  24 , respectively, within a single housing  20   a , which is covered by a conventional single lens  26 . The parking or DRL LED  22  is white in color and acts as the parking light. LED  24  is amber in color to provide a turn signal, both as described above. In one embodiment, the light sources are two chips from a single LED (called bichip LED). According to another embodiment, each light source are a chip of a single LED (called monochip), LEDs being distinct from one other. 
     Alternately, two different separate or integral lenses ( FIG. 6 ) can be used, separated at a divider  26   a . Further, one lens or a portion  26   b  of the lens  26  that covers or is in front of the turn indicator LED  24  may be colored amber to act as a filter to generate amber light, even if a white diode were used as the turn indicator LED  24 . 
     It is important to note that with the arrangement of  FIG. 6 , only a single housing  20   a  is required for this embodiment. Note also that the LEDs  22  and  24  are hidden behind the lens  26  and permit or facilitate a more global integration of lamp designs and, advantageously, a reduction in space required for the separate functions. For ease of illustration, a single LED  22  and LED  24  for each function is presented, but it should be understood that a plurality of LEDs may be used for each function. 
       FIGS. 7A-7D  illustrate in simplified form the single housing  20   a  and LEDs  22  and  24 . During operation, the operation sequence shown in  FIGS. 7B-7E  occur. In  FIG. 7B , the parking or DRL light source or LED  22  is illuminated, and generates light that is white. The turn signal light source or LED  24  is off at this time. In  FIG. 7C , the parking or DRL light source or LED  22  is off, and the turn signal light source or LED  24  is illuminated and generates light that is amber in color. In  FIG. 7D , the parking or DRL light source or LED  22  is illuminated and generates light that is white. The turn signal light source or LED  24  is off at this time. In  FIG. 7E , the parking or DRL light source or LED  22  is off. The turn signal light source or LED  24  is illuminated and generates light that is amber in color. 
       FIG. 8  illustrates a significant feature of one embodiment of the invention. The turn signal, which is visually transmitted to other drivers, comprises two colors which alternate in time. The colors are white and amber in this case, and they can be viewed as time-multiplexed. This approach is different from an ordinary turn signal, which comprises a single flashing color. 
     In  FIG. 8 , the single-housing  20   a  approach of  FIGS. 6 and 7A-7B  is utilized. In  FIG. 8 , image A illustrates two white parking lights being projected or generated by the parking or DRL light source or LED  22  on each side of the vehicle V. In image B, a left-hand turn signal has been actuated by the driver, so the left-hand white parking light source or LED  22  is turned off and has been replaced by a display of the amber turn signal light generated by the turn signal light source or LED  24 . Note that the amber light emanates from the same single housing  20   a  and lens  26  as the previous white parking light did. 
     In image C of  FIG. 8 , the amber light of image B is turned off and is replaced by the white parking or DRL light generated by parking or DRL light source or LED  22  which is energized. Then, in image D, the left-hand parking light generated by the parking or DRL light source or LED  22  is turned off and is replaced by the amber light generated by parking or DRL light source or LED  24  which is energized. 
     Therefore, in the sequence of  FIG. 8 , a turn signal on the left side of the vehicle V (as viewed by the driver), takes the form of a light which flashes white, then amber, then white, then amber, and so on. In contrast, an ordinary turn signal flashes, for example, amber, then nothing, then amber, then nothing, and so on. Of course, the right-hand turn signal or light source or LED  24  and parking or DRL light source LED  22  operate in the same manner in the illustrative embodiment. 
     A control system  30  implements the operation for the embodiments described above.  FIGS. 6 and 9A-13  illustrate details of such a control system. Prior to explaining those  FIGS. 6 and 9A-13 , a simplified equivalent circuit or control shown in  FIG. 9A , will first be explained for ease of understanding. 
     In  FIG. 9A , a voltage source V 2  represents the main battery of the vehicle V of  FIG. 8 . In  FIG. 9A , switch S 1  represents a parking light switch so that the parking or DRL light source  10  is always energized during predetermined conditions under control of the driver, and switch S 2  represents a turn signal switch (not shown), which is commonly under the control of the operator of the vehicle and is typically on the left side of the steering wheel, at least in cars commonly used in the United States. 
     When the switch S 1  is closed (for example, when the vehicle V is started or the driver actuates the parking lights) and switch S 2  is open, the control circuit  30  in  FIG. 8  causes switch Q 1  in  FIG. 9A  to close, in a manner described later herein, thereby energizing parking or DRL light source or LED  22  to generate the white parking or DRL. The turn signal light source or LED  24  is not energized and remains dark. 
     When the switch S 2  alone is closed, as when the driver actuates a turn signal, and switch S 1  remains open, the control circuit  30  in  FIG. 8  causes switch Q 4  in  FIG. 9A  to close and open at a rate of about 1.51 Hertz (Hz). This causes the turn signal light source or LED  24  to flash at that same rate of about 1.51 Hz. The parking or DRL light source or LED  22  is not energized and remains dark during flashes of the turn signal light source or LED  24 . The switch Q 2  remains OFF because the switch S 1  is open 
     If both switches S 1  and S 2  are closed, as when the parking lights are on and the driver actuates a turn signal, the control circuit  30  causes switch Q 1  to periodically open and close, and switch Q 4  to assume the opposite state. That is, if Q 1  is closed, then Q 4  is open. If Q 1  is open, then Q 4  is closed and so on. This causes one, but not both, of either parking or DRL light source or LED  22  or the turn signal light source or LED  24  to illuminate. This alternate illumination is indicated and summarized by a plot or timing diagram TD in  FIG. 16B . Switch Q 2  in  FIG. 9A  assists this function to diphase the TI signal from DRL/PL therefore you have opposite state on DRL/PL signal detailed on  FIG. 16B . 
       FIG. 9B  shows the switches S 1  and S 2  of  FIG. 9A . Block SW in  FIG. 9B  contains definitions, which will be utilized to facilitate understanding. As block SW shows, when switch S 1  is open, it is defined as being in state A. When closed, switch S 1  is defined to be in state B. When switch S 2  is open, it is defined as being in state C, and when closed, switch S 2  is defined as being in state D. For ease of understanding, reference is made to the parking or DRL light source or LED  22  only, but this description applies to the parking or DRL light sources  10  and  14  mentioned earlier. Hence, the description herein relative to the turn signal light source or LED  24  equally applies to the turn signal light sources  12  and  16 . 
     In  FIG. 9B , voltage sources V 2  and V 3  represent the main battery of the vehicle V. As in  FIG. 9A , switch S 1  controls the parking or DRL light source or LED  22 . If that switch SI is open in  FIG. 9B , then the drain D 1  of Field Effect Transistor (FET) Q 1  is floating, so no current can pass to the parking or DRL LED  22 , which remains off, as indicated. 
     Transistor Q 2 , which is an NPN Bipolar Junction Transistor, BJT, does nothing at this time. It behaves as an open circuit because its base B 2  is pulled to ground by resistor R 2 , which shuts off Q 2 . Also, its collector C 2  is not applied to a source voltage at this time (because switch S 1  is open), which means that no current can pass through the transistor Q 2 . 
     As in  FIG. 9A , switch S 2  controls the turn signal light source or LED  24 . For simplicity, only a single switch S 2  is shown. However, in practice, there are two such conventional switches, both identical in function. One controls the left-side turn signal, and the other controls the right-side turn signal.  FIG. 14 , later explained, provides an example of left and right side operation. 
     When switch S 2  in  FIG. 9B  is open, as shown, the gate G 4  of FET Q 4  is pulled to ground by resistor R 5 , causing Q 4  to act as an open circuit. No current flows through the turn signal light source or LED  24 , so it is off. 
     Therefore, in  FIG. 9B , switches S 1  and S 2 , which are both open, cause both the parking or DRL light source or LED  22  and the turn signal light source or LED  24  to be off at this time. 
     In  FIG. 10 , switch S 1  is closed. This pulls gate G 1  of transistor Q 1  to a higher voltage, thereby turning on Q 1 . In turn, this causes current  11  to flow through parking or DRL light source or LED  22 . However, BJT Q 2  is off because its base B 2  is pulled low as explained earlier. This is true even though its collector C 2  now has a voltage applied by way of resistor R 1 . In addition, FET Q 4  is off, for the reasons explained in connection with  FIG. 9B . 
     Therefore, at this time, with switch S 1  closed and switch S 2  open, the parking or DRL light source or LED  22  is ON and the turn signal light source or LED  24  is off. 
     In  FIG. 11 , an example of switch S 2  being closed (i.e., a call for turn signal) and switch S 1  open (indicating no parking or DRL lamp) will now be explained. As shown, switch S 1  is open and switch S 2  is closed in the example. FET Q 1  is off because its drain D 1  is floating as is its gate G 1 . The parking or DRL light source or LED  22  receives no current and is, therefore, off. 
     The closed switch S 2  pulls the base B 2  of BJT Q 2  to a high voltage. However, since switch S 1  is open, there is no voltage applied to collector C 2  of BJT Q 2 , so BJT Q 2  is off. 
     The closed switch S 2  applies the train of voltage pulses indicated by V 1  to the gate G 4  of FET Q 4 . When a high pulse, VHI, is applied, transistor Q 4  turns on, and the turn signal light source or LED  24  is pulsed to go on. When a low pulse, VLO, is applied, transistor Q 4  turns off, terminating the current through turn signal light source or LED  24 . 
     Therefore, in  FIG. 11 , the parking or DRL LED  22  is off, and the turn signal light source or LED  24  pulses or flashes on and off. 
     In  FIG. 12 , both switches S 1  and S 2  are closed. This will occur when the parking or DRL light source or LED  22  is illuminated, and the driver activates a turn signal by turning the turn signal lever (not shown) on the steering column (not shown). The circuit of  FIG. 12  will reside in one of two conditions at this time, depending on whether VHI or VLO of voltage train V 1  passes through switch S 2 . 
     Assume that VHI is passed through switch S 2  in  FIG. 12 . VHI pulls the base B 2  of BJT Q 2  to a high voltage, thereby turning on BJT Q 2 . In turn, that pulls the collector C 2  to a low voltage, thereby pulling the gate G 1  of FET Q 1  to a low voltage. This turns off FET Q 1 , so parking or DRL light source or LED  22  is turned off at this time. 
     Note that voltage VHI is also applied to the gate G 4  of FET Q 4 , thereby turning on FET Q 4 , which turns on the turn signal light source or LED  24 . 
     Therefore, in  FIG. 12 , when VHI of voltage train V 1  is passed by switch S 2 , the parking or DRL light source or LED  22  is off and the turn signal light source or LED  24  is on. 
     In  FIG. 13 , it is assumed that VLO of voltage train V 1  is passed by switch S 2 . That applies a low voltage to the base B 2  of BJT Q 2 , thereby turning off BJT Q 2 , which turns off the turn indicator LED  24 . In this regard, voltage VLO is also applied to the gate G 4  of FET Q 4  and pulls the gate G 4  to a low voltage. This turns off FET Q 4 , thereby turning off turn indicator LED  24 . 
     Now the gate G 1  of FET Q 1  is pulled to a high voltage, by way of resistor R 1  being connected to voltage V 2 . This turns on FET Q 1 , thereby illuminating parking or DRL light source or LED  22 . 
     Therefore, in  FIG. 13 , the parking or DRL LED  22  is pulsed on when the turn signal light source or LED  24  is pulsed off. 
     To repeat, when switches S 1  and S 2  are both closed, the situation alternates between that of  FIG. 12  and that of  FIG. 13 . When parking or DRL light source or LED  22  goes or is pulsed on, the turn signal light source or LED  24  is off. When the latter turn signal light source or LED  24  goes or is pulsed on, parking or DRL light source or LED  22  is off. 
     From one point of view, in  FIGS. 12 and 13 , switches S 1  and S 2  both attempt to turn on their respective LEDs. Switch S 1  attempts to turn on the parking or DRL light source or LED  22 . Switch S 2  attempts to turn on the turn signal light source or LED  24 , but only when VHI is applied to switch S 2 . However, VHI turns off the transistor Q 2 , thereby turning off FET Q 1 . 
     Consequently, the event which turns on FET Q 4 , namely, the occurrence of VHI, serves to also turn off FET Q 1 , by turning on BJT Q 2 . So the parking or DRL light source or LED  22  and turn signal light source or LED  24  are forced into opposite states. When one is on, the other is off. 
     ADDITIONAL CONSIDERATIONS AND ADVANTAGES 
     1. A significant feature of one embodiment of the invention is that both lamps or LEDs  22  and  24  in  FIG. 6  can be contained within the single housing  20   a  as shown in  FIGS. 6-7E , compared with the dual-housing approach of the embodiment of  FIGS. 4A-5D . This can reduce manufacturing and assembly costs. Further, the LEDs  22  and  24  can be more closely spaced together in the single housing  20   a  shown in  FIG. 6  compared to the two housing approach shown in  FIGS. 4A-5D , thereby reducing size and space requirements. This provides the result that, when the LEDs  22  and  24  alternate in illumination, they resemble a single flashing item through lens  26 , which alternately produces white and amber light. This situation is contrasted with the embodiment of  FIGS. 4A-5D  wherein any analogous flashing would be perceived as a flashing light which jumps left and right between 10 and 12 (for a right-hand turn or 14 and 16 for a left-hand turn), similar to a so-called “wig-wag” crossing lights used at railroad crossings. 
     2. One characteristic of the single housing  20   a  in  FIG. 6  is that two separate, independently operable, illumination assemblies (one pair on each side of the vehicle V) are not present or required, as in the prior art shown in  FIG. 2 . 
     3. It should be understood that the control system or circuit  30  of  FIGS. 9A and 9B  will control, for example, the turn signal on the left side of the vehicle V and the parking light or DRL also on the left side of the vehicle V. That is, LED  22  is located on the left side, as is LED  24 . The identical control system or circuit  30  controls the turn signal and parking light or DRL on the right side of the vehicle V. These two control systems are represented separated by blocks  30 A and  30 B in  FIG. 6 . It should be understood that the control system or circuit  30  may be a separate component integrated on the same printed circuit board as the control circuit components (not shown) in each light housing, such as light housing  20   a . Alternatively, the control system or circuit  30  could be provided on a separate printed circuit board mounted with other vehicle electronics (not shown), such as with conventional turn signal electronics. 
     4. Although preferred, the single-lens, single housing  20   a  approach of  FIG. 6  is not required. The dual-housing system of  FIGS. 4A-5D  can be used with the embodiments of the invention. 
     5.  FIG. 14  illustrates the components labeled as LEFT SIDE are analogous to those described in  FIGS. 9A-13  and operate similarly. Those components control light sources or LEDs  22 L and  24 L, which are on the left side of the vehicle V. The components labeled RIGHT SIDE control light sources or LEDs  22 R and  24 R, which are on the right side of the vehicle V. 
     There are at least two differences between the LEFT SIDE and RIGHT SIDE components. One is that switch S 1  is eliminated from the RIGHT SIDE. Switch S 1 L controls both light sources or LEDs  22 L and  22 R. 
     A second difference is that no additional voltage train V 1  (as shown in  FIGS. 9B-13 ) is shown on the RIGHT SIDE. A single voltage train V 1 L is provided. It is used by the LEFT SIDE or the RIGHT SIDE components when needed, but not both at once. 
     In  FIG. 14 , switch S 1 L turns both park lamp LEDs on and off in the manner described earlier relative to  FIGS. 9B-13 . If switch S 1 L is off or open, then (1) switch S 2 L operates the left turn signal light source or LED  24 L, and (2) switch S 2 R operates the right turn signal light source or LED  24 R, in the manner described earlier relative to  FIGS. 9B-13 . If switch S 1 L is on or closed, then if switch S 2 L is closed, the left parking or DRL light source or LED  22 L flashes alternately with the left turn signal light source or LED  24 L in the manner described earlier. The right parking or DRL light source or LED  22 R is illuminated continuously and right turn signal light source or LED  24 R is off. 
     If switch S 1 L is closed and if switch S 2 R is closed, the right parking or DRL light source or LED  22 R flashes alternately with the right turn signal light source or LED  24 R. Note that the left parking or DRL light source LED  22 L is illuminated continuously and left turn signal light source or LED  24 L is off. 
     During normal operation, an interlock IL in  FIG. 15  is generally provided to prevent turn indicator switches S 2 L and S 2 R from being actuated simultaneously because simultaneous actuation would imply issuance of a simultaneous turn in both the left and right directions. In contrast, if a hazard warning signal were initiated, the hazard warning signal would flash both sides at the same time. 
     The apparatus of  FIG. 14  prevents a parking lamp LED from illuminating at the same time as its adjacent turn signal LED. For example, if left turn signal light source or LED  24 L is energized or illuminated, then the circuit  30  prevents left parking or DRL light source or LED  22 L from illuminating simultaneously. Those two light sources or LEDs  22 L and  24 L are required to illuminate or flash alternately at different times as explained earlier. 
     6. For ease of understanding,  FIG. 15  includes a simplified representation of  FIG. 14 . The bracket labeled PRIOR ART indicates that LEDs PL and SL are controlled independently by respective switches SA and SB. (In practice a relay or equivalent, not shown, may be interposed between a switch and the LED, to handle a large current.) That is, the operation of switch SB does not affect the illumination of LED PL. They are independent. 
     In contrast, the embodiments being described provide the control system and circuit  30  within the bracket labeled  30 . The control system and circuit  30  makes the operation dependent as explained above. For example, the left park lamp LED, labeled PL-L, cannot operate independently from the left turn signal LED, labeled SL-L. Further, because of the interlock IL, the left turn signal LED, labeled SL-L, cannot operate independently of the right turn signal LED, which is labeled SL-R. 
     7.  FIG. 16A  is a truth table that summarizes the different operational states and illustrates one type of dependency in the operation. When both switches S 1  and S 2  in  FIG. 9A  are open, both LEDs  52  and  53  are off, as  FIG. 16 , top row, indicates. 
     As illustrated in the second row of  FIG. 16 , when switch S 1  is open and switch S 2  is closed, the appropriate turn signal flashes and no parking lights are displayed. 
     As the third row of  FIG. 16  indicates, when switch S 1  is closed and switch S 2  is open, the parking or DRL lights go on, but no turn signal illuminates. 
     As the last row in  FIG. 16  indicates, when both switches S 1  and S 2  are closed, the appropriate turn signal light source or LED  24  alternates with its adjacent parking light source or LED  22 . It should be understood that the non-adjacent parking light source or LED  22  illuminates continuously and the other turn signal light source or LED  22  is off. 
     8.  FIG. 17  illustrates the range of flash rates for a turn signal allowed in North America. This illustrates that a primary factor which would be allowed to change is the flash rate/frequency of the turn signal, which would affect the countering flash of the parking or DRL light source throughout the duration of the turn signal. 
     This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the bullet list in the Summary of the Invention and the claims. 
     While the system, apparatus, process and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus, process and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.