Abstract:
Laser display system having at least more than two lasers, and a display panel for receiving an electrical picture signal, and regulating a quantity of light from the laser to form an image based on the electrical picture signal, including a light superimposer of optical fibers for superimposing the lights from the lasers, thereby improving an optical efficiency to provide a bright and clear picture.

Description:
This application claims the benefit of the Korean Application No. P2003-0013083 filed on Mar. 27, 2003, which is hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to projection display systems, and more particularly, to a laser display system that uses a laser as a light source. 
   2. Background of the Related Art 
   Though a lamp has been used as a light source of a projection display system, recently, a laser display system is under development in which a laser is used in place of the lamp. The laser display system has advantages in that a clear picture can be provided since colors of a picture are clear, and close to pure colors, a range of reproduction of the colors is wide, and contrast of the picture is high. 
     FIG. 1  illustrates a related art laser display system. 
   Referring to  FIG. 1 , the related art laser display system is provided with a laser  10  for emitting a beam of light, a focusing device  120  for focusing the beam of light, an acousto-optic modulator (AOM)  130  for regulating transmission of the beam of light incident thereon from the focusing device  120  based on a picture signal, a polygon mirror  140  for turning, and reflecting the beam of light incident thereon from the AOM  130 , to provide a horizontal image of the picture signal, a galvanometer  150  for moving up/down at a fix angle repeatedly for providing a vertical image of the picture signal, and a screen  160  for displaying the images provided at the polygon mirror  140  and the galvanometer  150 . 
   The operation of the related art laser display system will be described. 
   The laser  110  emits the beam of light, and the focusing device  120  focuses the beam of light. Then, the AOM  130  regulates transmission of the focused beam of light in response to an electric signal related to the picture signal. 
   The polygon mirror  140  turns, and reflects the beam of light to provide the horizontal image, and the galvanometer  150  moves up/down at a fix angle repeatedly, to provide the vertical image of the picture signal. According to this, the screen  160  can display an image provided thus. 
     FIG. 2  illustrates a related art laser display system. 
   Referring to  FIG. 2 , the related art display system is provided with a laser  210  for emitting a beam of light, an illuminating device  220  for irradiating the beam of light to a display panel to be described later, a display panel  230  for regulating a quantity of light from the illuminating device  220  based on a picture signal, to provide an image, a projector  240  for enlarging and projecting the image, and a screen  250  for displaying the image. 
   The operation of the related art laser display system will be described. 
   When the laser  210  emits a beam of light, the illuminating device  220  irradiates the beam of light to the display panel  230 . Then, the display panel  230  regulates a quantity of light based on an electric picture signal, to form a picture to be displayed. The display panel  230  is in general an LCD (Liquid Display Panel). 
   Thereafter, the picture formed at the display panel  230  is enlarged at the projector  240 , and displayed on the screen  250 . 
   In the meantime, a red laser, a green laser, and a blue laser are used as the laser light source, for realizing a color picture. That is, by projecting a superimposed light of red, green, and blue colors to the screen, the user can watch the color picture. The lights are superimposed by the following method in the related art. 
     FIG. 3  illustrates a related art light superimposer. 
   Referring to  FIG. 3 , the related art light superimposer is provided with a red laser  310 , a green laser  320 , a blue laser  330 , first, and second filters  340 , and  350  each for transmitting, or reflecting a particular wavelength. 
   The related art light superimposer is operated as follows. 
   The first filter  340  superimposes lights from the red laser and the green laser, and the second filter  350  superimposes the light superimposed at the first filter  340  with a light from the blue laser, to display the superimposed light of the three colors on the screen  360 . 
   However, a system of the light superimposer in  FIG. 3  has problems in that there is a spatial limitation in arranging the light sources, leading a size of the system large because it is required that each of the first filter  340  and the second filter  350  is arranged at 45° from a path of light without fail, and the lights from the lasers are incident on the filter at 90° with respect to each other. 
   That is, if the 45° arrangement of the first filter  340  and/or the second filter  350  from the path of light fails, or the light incident on the filter at 90° with respect to each other fails, transmissivity of the filters  340  and  350  changes, to have non-uniform light distribution. 
     FIG. 4  illustrates a light superimposer of optical fibers. 
   That is, referring to  FIG. 4 , the light superimposer is provided with a red laser  410 , a green laser  420 , a blue laser  430 , and optical fibers  440  connected to the lasers respectively, for irradiating the color lights to the screen  450 . 
   The light superimposer of optical fibers reduces the spatial limitation caused by arrangement of the light source, to reduce a size of the system. However, putting output surfaces of the optical fibers together exactly on one plane has been very difficult. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a laser display system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide a laser display system which enables an effective superimposition of lights from more than two lasers. 
   Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the laser display system having two or more than two lasers as light sources, includes a light superimposer of optical fibers for superimposing beams of light from the lasers, a rotational color separator for separating a superimposed beam light into a red beam of light, a green beam of light, and blue beam of light in succession again, an illuminating device for irradiating the red, green, and blue beams of light separated in succession to a display panel to be described later, the display panel for receiving an electrical picture signal, and regulating a quantity of light from the illuminating device based on the electric picture signal, to form an image, and a controller for matching a color area of the beam of light from the rotational color separator to a color area of a color signal from the display panel. 
   The light superimposer makes total reflection of the beam of light incident thereon to proceed along a core of the optical fiber by using a difference of refractive indices between the optical fiber core and an optical fiber cladding. 
   The light superimposer includes at least one optical fiber inlet part for receiving the red, green, and blue beams of light, an optical fiber superimposing part having at least one optical fiber inlet part unitized into one for superimposing the red, green, and blue beams of light to form a white beam of light, and an optical fiber output part for providing the white beam of light. 
   In other aspect of the present invention, there is provided a laser display system including a red laser, a green laser, and a blue laser for emitting a red beam of light, a green beam of light, and a blue beam of light, a light superimposer of optical fibers for superimposing the red, green, and blue beams of light from the lasers respectively, an illuminating device for irradiating the superimposed light to a display panel, a display panel for receiving an electrical picture signal, and regulating a quantity of light incident thereon from the illuminating device to form an image based on the electrical picture signal, and a controller for receiving, and separating the picture signal into red, green, and blue signals, and turning on a relevant color laser in succession. 
   The light superimposer makes a light incident thereon to proceeds along an optical fiber core by reflecting the light totally by using a difference of refractive indices between the optical fiber core, and an optical fiber cladding. 
   The light superimposer includes at least one optical fiber inlet part for receiving the red, green, and blue beams of light, an optical fiber superimposing part having at least one optical fiber inlet part unitized into one for superimposing the red, green, and blue beams of light to form a white beam of light, and an optical fiber output part for providing the white beam of light. 
   It is to be understood that both the foregoing description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings; 
       FIG. 1  illustrates a diagram of one example of a related art laser display system; 
       FIG. 2  illustrates a diagram of another example a related art laser display system; 
       FIG. 3  illustrates a diagram of a related art light superimposer, schematically; 
       FIG. 4  illustrates a diagram of a related art light superimposer of optical fibers, schematically; 
       FIG. 5  illustrates a diagram of a laser display system in accordance with a first preferred embodiment of the present invention; 
       FIG. 6  illustrates a diagram of a superimposer of the present invention, schematically; 
       FIG. 7  illustrates a diagram of a rotational color separator of the present invention; 
       FIGS. 8A˜8D  illustrate a timing chart for describing a controller in accordance with a first preferred embodiment of the present invention; 
       FIG. 9  illustrates a diagram of a laser display system in accordance with a second preferred embodiment of the present invention; and 
       FIGS. 10A˜10E  illustrate a timing chart for describing a controller in accordance with a second preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
   First Embodiment 
     FIG. 5  illustrates a diagram of a laser display system in accordance with a first preferred embodiment of the present invention. 
   Referring to  FIG. 5 , the laser display system includes a red laser  511 , a green laser  512 , and a blue laser  513  for emitting a red beam of light, a green beam of light, and a blue beam of light respectively, a light superimposer  520  for superimposing the red beam of light, the green beam of light, and the blue beam of light, a rotational color separator  530  for separating the superimposed beam of light into the red beam of light, the green beam of light, and the blue beam of light in succession, an illuminating device  540  for irradiating the beams of light separated in succession to a display panel to be described later, a display panel  550  for receiving an electrical picture signal from a controller to be described later, and regulating a quantity of light from the illuminating device  540  based on the electrical picture signal, to form an image, a projector  560  for enlarging, and projecting the image, a screen  570  for displaying the enlarged image, and a controller  580  for matching a color area of the beam of light from the rotational color separator  530  to a color area of a color signal from the display panel  550 . 
   The operation of the laser display system of the present invention will be described with reference to the attached drawings. 
   The red laser  511 , the green laser  512 , and the blue laser  513  emit a red beam of light, a green beam of light, and a blue beam of light, respectively. As shown in  FIG. 6 , the red beam, the green beam, and the blue beam enter into relevant optical fiber input parts  620  of the light superimposer  520 . Then, the red beam, the green beam, and the blue beam are reflected totally owing to a difference of refractive indices between an optical fiber core  630  and an optical fiber cladding  640 , to proceed along respective optical fiber cores  630 , until the red, green, and blue beams are superimposed and turned into a white beam of light at an optical fiber superimposing part  650 . The optical fiber superimposing part  650  has respective optical fiber cores  630  unitized into one to form one optical fiber core. The white beam of light proceeds along the one optical fiber core until the white beam of light comes out of the optical fiber output part  660 . 
   The light superimposer  520  in  FIG. 6  requires no alignment of the white lights from the related art optical fiber output parts on one plane vertically, and no binding and fastening of the related art optical fiber output parts. 
   Then, the white light from the light superimposer  520  transmits the rotational color separator  530 , when the rotational color separator  530  separate the white light into red, green, and blue beams of light in succession, and provides to the display panel  550 . 
   The process will be described in more detail, with reference to  FIGS. 8A˜8D . 
   For forming a color picture by using the display panel  550 , a picture time period is divided into time periods of red, green, and blue color lights, and the red, green, and blue color lights are displayed on a screen in succession. That is, if the one picture time period is 1/60 seconds, the red, green, and blue color lights are displayed for 1/180 seconds respectively, to display the color picture. 
   Referring to  FIG. 7 , the rotational color separator  530  has R, G, B areas for transmitting red, green, and blue beams of light respectively, such that, when the white color is incident on one of the R, G, B areas as the rotational color separator  530  rotates, only a color of the area transmits. That is, the red, green and blue beams of light are separated in succession, and proceeds to the display panel  550 . 
   Then, the display panel  550  receives the red, green, and blue beams of light, and forms one color picture. That is, the controller  580  receives the picture signal, separates the picture signal into red, green, and blue color signals, and forwards to the display panel  550 . Then, the display panel  550  displays the red, green, and blue color signals in succession, to form one color picture. In this instance, for matching a color of light separated at the rotational color separator  530  to a color of light displayed on the display panel  550 , a sensor  710  is provided at the rotational color separator  530 , for sensing the color of light transmitted through the rotational color separator, and providing to the display panel  550  through the controller  580 . Then, the color of light separated at the rotational color separator  530  and the color of light displayed on the display panel  550  are synchronized, to form an exact color picture. 
   This will be described in more detail. 
   Referring to  FIG. 8B , the beam of light is irradiated to the display panel  550  from the rotational color separator  530  by the illuminating device  540 . In this instance, the beam of light simply has red, green, and blue color areas. Then, the controller  580  receives a picture signal (an electric signal having red, green, and blue colors mixed therein) as shown in  FIG. 8A , and transmits to the display panel  550  in synchronization to a sensor signal as shown in  FIG. 8C . Then, a color picture as shown in  FIG. 8D  is displayed on the display panel  550 . That is, a color of light the same with the rotational color separator  530  is displayed on the display panel  550 . 
   Thereafter, the picture formed on the display panel  550  is enlarged, and projected to the screen  570  by the projector  560 . 
   Second Embodiment 
     FIG. 9  illustrates a diagram of a laser display system in accordance with a second preferred embodiment of the present invention. 
   Referring to  FIG. 9 , the laser display system includes a red laser  911 , a green laser  912 , and a blue laser  913  for emitting a red beam of light, a green beam of light, and a blue beam of light, a light superimposer  920  for superimposing the red, green, and blue beams of light, an illuminating device  930  for irradiating the superimposed beam of light to a display panel to be described later, a display panel  940  for receiving the electric picture signal from a controller to be described later, and regulating a quantity of light incident thereon from the illuminating device  930  to form an image based on an electric picture signal, a projector  950  for enlarging, and projecting the image, a screen  960  for displaying the image, and a controller  970  for receiving, and separating the picture signal into red, green, and blue color signals, and turning on/off one of the lasers relevant to the red, green, and blue color signals in succession. 
   The operation of the laser display system of the present invention will be described with reference to the attached drawings. 
   The red laser  911 , the green laser  912 , and the blue laser  913  emit a red beam of light, a green beam of light, and a blue beam of light, respectively. As shown in  FIG. 6 , the red beam, the green beam, and the blue beam enter into relevant optical fiber input parts  620  of the light superimposer  920 . Then, the red beam, the green beam, and the blue beam are reflected totally owing to a difference of refractive indices between an optical fiber core  630  and an optical fiber cladding  640 , to proceed along respective optical fiber cores  630 , until the red, green, and blue beams are superimposed and turned into a white beam of light at an optical fiber superimposing part  650 . The white beam of light proceeds along one optical fiber core until the white beam of light comes out of the optical fiber output parts  660 . 
   The light superimposer  920  in  FIG. 6  requires no alignment of the white lights from the related art optical fiber output parts on one plane vertically, and no binding and fastening of the related art optical fiber output parts. 
   The white light from the optical fiber output part is irradiated to the display panel by the illuminating device, which will be described with reference to  FIGS. 10˜10E . 
   The controller  970  receives a picture signal (an electric signal having red, green, and blue color signals mixed therein) as shown in  FIG. 10A , separates the picture signal into the red, green, and blue color signals, and turns on/off the red laser  911 , the green laser  912 , and the blue laser  913  with reference to the separated signals, for providing the R, G, B color signals as shown in  FIGS. 10B˜10D  in succession. Then, a color picture as shown in  FIG. 10D  is displayed on the display panel  940 . That is, a picture signal the same with the picture signal provided to the controller  970  is formed on the display panel  940 . 
   Thereafter, the picture formed on the display panel  940  is enlarged, projected to, and displayed on the screen  960  by the projector  950 . 
   As has been described, the laser display system of the present invention has the following advantages. 
   The effective superimposition and display of the beams of light from the red laser, the green laser, and the blue laser permits to improve a light efficiency, to provide a bright and clear picture. 
   The uniform distribution of the beams of light from the red laser, the green laser, and the blue laser permits a uniform brightness of the picture. 
   The simple arrangement of the red, green, and blue lasers, and optical elements permits to fabricate a smaller laser display system. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.