Abstract:
A projection television includes a video processor to process input video signals, a single CRT to project light according to the processed video signals, a color wheel located in a front of the CRT to filter the light projected from the CRT into predetermined colored light, and a controller to control a rotation of the color wheel according to the input video signals. The projection television uses the color wheel to realize colored light by dividing light produced by the single CRT.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit under 35 U.S.C. §119 from Korean Patent Application No. 2004-108893, filed on Dec. 20, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present general inventive concept relates to a projection television, and more particularly, to a color projection television with a single cathode ray tube (CRT).  
         [0004]     2. Description of the Related Art  
         [0005]      FIG. 1  illustrates a conventional projection television.  
         [0006]     As illustrated in  FIG. 1 , the conventional projection television employs three CRTs. Each CRT projects one of red, green, and blue to realize a color image.  
         [0007]     That is, each CRT projects one of the red, the green, and the blue to realize the color image and has one of red, green and blue colored-lenses that are attached to a front part of the corresponding one of the CRTs.  
         [0008]     However, as illustrated in  FIG. 1 , in case of using the three CRTs, it is complicated to control an axis of each CRT, an optical axis and an adjustment of a total conjugate length (TCL). A convergence may occur due to a difference of locations of the CRTs. Therefore, a special step for the adjustment of the convergence may be required.  
       SUMMARY OF THE INVENTION  
       [0009]     The present general inventive concept provides a projection television that uses a color wheel as to realize colored images by dividing light emitted from a single CRT into colored lights.  
         [0010]     Additional aspects and/or advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present general inventive concept.  
         [0011]     The foregoing and/or other aspects of the present general inventive concept may be achieved by providing a projection television comprising a video processor to process input video signals, a single CRT to project light according to the processed video signals, a color wheel located in a front of the CRT to filter the light projected from the CRT into predetermined colored-light corresponding to the respective processed video signals, and a controller to control a rotation of the color wheel according to the input video signals.  
         [0012]     The video processor may process the input video signals to divide into R, G, and B signals, and to merge or arrange the R, B, and G signals in a sequence, and the CRT projects the light according to the merged R, G, and B signals in the sequence.  
         [0013]     The controller may control the color wheel to filter the light into red, green and blue colored-light based on the R, G, and B signals corresponding to the light which is projected from the CRT.  
         [0014]     The colored light may comprise red, green and blue colored-light and the color wheel may comprise red, green and blue color filters to generate the red, green and blue colored-light from the projected light.  
         [0015]     The CRT may comprise a colorless lens through which the light projected from the CRT is transmitted.  
         [0016]     The controller may control the color wheel to rotate according to a predetermined period corresponding to a frequency of the input video signals.  
         [0017]     The foregoing and other aspects of the present general inventive concept may also be achieved by providing a projection television including a single CRT to project light according to a video signal, a color wheel having a plurality of filters to receive the light and to generate colored light, a mirror to reflect the colored light and a screen to project the reflected colored light as an image.  
         [0018]     The foregoing and other aspects of the present general inventive concept may also be achieved by providing a projection television including a housing, a single CRT disposed in the housing to project a first, a second, and a third light according to a first, a second, and a third video signal, a color wheel disposed in the housing to generate a first, a second and a third colored light according to the projected first, second and third light, respectively, a mirror to sequentially reflect the first, second and third colored-light, and a screen to display an image according to the reflected first, second and third colored light. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
         [0020]      FIG. 1  illustrates a conventional projection television.  
         [0021]      FIG. 2  is a control block diagram of a projection television according to an embodiment of the present general inventive concept.  
         [0022]      FIG. 3  is a perspective view of a projection television according to an embodiment of the present general inventive concept. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Reference will now be made in detail to the embodiment of the present general inventive concept, illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below so as to explain the present general inventive concept by referring to the figures.  
         [0024]     As shown in  FIG. 2 , a projection television according to an embodiment of the present general inventive concept comprises a video processor  10 , an antenna  11 , a single CRT  20 , a color wheel  30 , a mirror  40 , a screen  50  and a controller  60 .  
         [0025]     The video processor  10  processes an input video signal, for example a broadcasting signal received through the antenna  11 , and may comprise a tuner (not shown) that selects a channel of the broadcasting signal so as to receive the broadcasting signal according to the selected channel. The video processor  10  may process other input video signals besides the broadcasting signal.  
         [0026]     The video processor  10  decodes, amplifies and processes the input video signal such as the broadcasting signal, and outputs the processed signals to the CRT  20 . The input video signal is separated into R, B, and G signals during processing by the video processor  10 , and the R, B, and G signals are provided to the CRT  20  after being merged or arranged in a sequence.  
         [0027]     The CRT  20  transforms the R, G, and B signals from the video processor  10  into optical signals, for example, light corresponding to the R, G, and B signals, and outputs the light. The CRT  20  comprises a cathode, an electron gun, a deflection yoke, a phosphor, a lens, etc.  
         [0028]     The electron gun installed in the cathode of the CRT  20  emits cathode electrons according to the R, G, B signals processed by the video processor  10 , and the cathode electrons are scanned through a tube toward an anode. Then the deflection yoke deflects the electrons in the up, down, right and left directions when the electron gun transforms the sequence of R, G, B signals into the electrons to be scanned.  
         [0029]     The electrons are transformed into light by landing on a fluorescent substance. Brightness of an image on the screen  50  is proportional to the number of electrons because an intensity of a stimulus to the fluorescent substance depends on the number of electrons.  
         [0030]     Accordingly, the light intensity is modulated or changed depending on the number of the electrons when the electrons are transformed into light.  
         [0031]     The CRT  20  comprises a lens, and the lens comprises a colorless C-lens. The light passing through the C-lens is output as light such as a white light (comprising components having wave lengths between 290 nm˜810 nm).  
         [0032]     After passing through the C-lens, the light is divided into red, green and blue colored-light by the color wheel  30  disposed in front of the C-lens at a predetermined distance.  
         [0033]     The color wheel  30  comprises red, green and blue color filters. When the optical signals according to R, G and B signals are projected through the CRT  20 , the optical signals are transformed into red, green or blue colored-light by the color filter.  
         [0034]     The red, green and blue colored-light are projected to the screen  50  after being reflected by the mirror  40 . Accordingly a user may see a colored image displayed on the screen  50 , corresponding to the input video signal.  
         [0035]     The controller  60  controls the video processor  10  and the CRT  20 . The controller  60  may be realized by a micro controller or other devices suitable to perform the intended purpose. The controller  60  controls the rotation of the color wheel  30  and based on the R, G and B signals the respective colored-light is projected from the CRT  20 .  
         [0036]     Also, the controller  60  controls the rotation of the color wheel  30  to rotate with a predetermined frequency, the frequency being determined based on a frequency of the input video signals.  
         [0037]     As an example, the color wheel  30  rotates 60 times per second when the frequency is 60 Hz in a national television system committee (NTCS) method, and the CRT  20  projects the light based on the R, G and B signals in sequence whenever the color wheel  30  rotates. In contrast to the conventional projection television, when the number of CRTs is three the CRTs scan the respective beam of the electron in each of the three CRTs. However, the single CRT  20  according to the present general inventive concept scans a beam of the light three times faster than the conventional projection television.  
         [0038]     The controller  60  controls a frequency of rotation of the color wheel  30  based on the frequency of the input video signals projected from the CRT  20  and the R, G and B signals corresponding to the input video signal. Also, the controller  60  controls the light to divide into red, green and blue colored-light by passing through the color filter on the color wheel  30 .  
         [0039]     In other words, the controller  60  controls the color wheel  30  to filter the light into the red, green and blue colored-light based on the order of the R, G and B signals in the sequence.  
         [0040]     The controller  60  controls the change of the light into the red, green and blue colored-light by controlling the color wheel  30  to rotate according to a determined period, and to locate the color wheel  30  so that the R, G, and B color filters disposed in front of the CRT  20  correspond to the respective R, G, or B signal in the sequence.  
         [0041]     The configuration of the embodiment of the projection television according to the present general inventive concept will be described by referring to  FIG. 3 .  
         [0042]     As shown in  FIGS. 2 and 3 , the projection television includes a housing  70  to accommodate a CRT, a color wheel, a mirror and a screen and the light projected from the CRT  20  is divided in the red, green and blue colored-light by passing through the color wheel  30 . The color wheel  30  comprises the red, green and blue color filters in sequence, and rotates according to the frequency of the input video signal and correlated with the sequence of the R, G and B signals by the controller  60 .  
         [0043]     The red, green and blue colored-light resulting from the light passing through the color wheel  30  are reflected on the mirror  40  and projected onto the screen  50 . Accordingly, a user may see a colored image corresponding to the input video signal.  
         [0044]     A location of the colored-light incident on the screen  50  is determined by an angle of reflection, and the angle of the reflection is controlled by the deflection yoke as described above.  
         [0045]     Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.