Abstract:
An optical engine apparatus magnifying and projecting an image beam formed by a display device on a screen, the optical engine apparatus including a light source having a bulb generating light and a reflection mirror reflecting the light provided adjacent to the bulb; and an optical filter inclinedly provided to reflect light components unnecessary for forming an image back to the light source, and to reflect the light components toward a lower portion of the reflection mirror which is positioned below the bulb. With this configuration, loss of light generated from a light source and projected to a display device is minimized, and brightness is improved. In addition, an optical path transformation unit is accommodated in an accommodation casing minimizing leaking of the light to thereby maintain good quality and protect from contamination due to dust or foreign substances.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of Korean Patent Application No. 2004-33630 filed on May 12, 2004 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present general inventive concept relates to an optical engine, and more particularly, to an optical engine with an improved light source.  
         [0004]     2. Description of the Related Art  
         [0005]     An optical engine apparatus projects a light emitted from a light source toward a display device, such as a liquid crystal display (LCD) or a digital micro-mirror display (DMD), so as to form an image beam, and displays a picture by magnifying and projecting the image beam onto the screen.  
         [0006]     As an example of the optical engine, a projector is disclosed in Korean Patent No. 0202548, the projector comprising a light source including a lamp and a reflection mirror; a ultra violet ray/infrared radiation (UV/IR) filter vertically aligned to the light source and cutting the ultra violet ray and the infrared radiation; and a projection lens projecting an image beam formed through the LCD on a screen.  
         [0007]     However, as shown in  FIG. 7 , the UV/IR filter  140  of such a conventional projector is vertically aligned to the lengthwise direction of the light source, and thus the light emitted from a bulb  117  is reflected back to the light source together with unwanted ultra violet ray and infrared radiation by the UV/IR filter when the light is transmitted to the UV/IR filter  140 . Herein, the unwanted ultra violet ray and infrared radiation reflected back to the light source by the UV/IR filter are converged at the bulb  114  causing damage to the bulb  117 . Accordingly, the light source  116  incidently stops working, life expectancy of the light source  116  is shortened and its quality is degraded.  
       SUMMARY OF THE INVENTION  
       [0008]     Accordingly, it is an aspect of the present general inventive concept to provide an optical engine apparatus with a light source prevented from being damaged due to unwanted light so as to optimize quality of the light source while extending its life expectancy.  
         [0009]     Additional aspects and/or advantages of the 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 general inventive concept.  
         [0010]     The foregoing and/or other aspects and advantages of the present general inventive concept are achieved by providing an optical engine apparatus magnifying and projecting an image beam formed by a display device on a screen, the optical engine apparatus comprising a light source comprising: a bulb generating light and a reflection mirror reflecting the light provided adjacent to the bulb; and an optical filter inclinedly provided so as to reflect light components unnecessary for forming an image back to the light source, and to reflect the light components toward a lower portion of the reflection mirror which is positioned below the bulb.  
         [0011]     According to an embodiment of the present general inventive concept, the optical filter is inclinedly disposed with respect to a traveling line of the light from the light source so that an upper portion of the optical filter is inclined toward the light source and a lower portion of the optical filter is inclined away from the light source.  
         [0012]     According to an embodiment of the present general inventive concept, the optical filter is inclined leftward or rightward with respect to the traveling line of the light from the light source while the upper portion thereof is inclined toward the light source and the lower portion thereof is inclined away from the light source.  
         [0013]     According to an embodiment of the present general inventive concept, the optical filter cuts at least one of ultra violet rays and infrared radiation in the light emitted from the light source.  
         [0014]     According to an embodiment of the present general inventive concept, the optical engine apparatus further comprises a color wheel assembly to which the light passed through the optical filter is transmitted, and the optical filter is inclinedly coupled to a side of the color wheel assembly.  
         [0015]     According to an embodiment of the present general inventive concept, the color wheel assembly comprises an optical filter mounting part provided in a side of the color wheel assembly, and accommodating the optical filter to be inclined at a given angle; and an optical filter supporting bracket coupled to the optical filter mounting part and supporting the optical filter accommodated at the optical filter mounting part.  
         [0016]     The foregoing and other aspects and advantages of the present general inventive concept are also achieved by providing an optical engine apparatus magnifying and projecting an image beam formed by a display device on a screen, the optical engine apparatus comprising: a light source emitting light; and an optical filter inclined leftward or rightward with respect to a traveling line of the light from the light source, and cutting off the light components in the light emitted from the light source.  
         [0017]     According to an embodiment of the present general inventive concept, the optical filter cuts at least one of ultra violet rays and infrared radiation in the light emitted from the light source. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     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 accompany drawings of which:  
         [0019]      FIG. 1  is a combined perspective view of an optical engine apparatus according to an embodiment of the present general inventive concept;  
         [0020]      FIG. 2  is an exploded perspective view of the optical engine apparatus in  FIG. 1 ;  
         [0021]      FIG. 3  is an exploded perspective view of a color wheel assembly and a UV cut filter in  FIG. 2 ;  
         [0022]      FIG. 4  is a combined perspective view of the color wheel assembly and the UV cut filter in  FIG. 2 ;  
         [0023]      FIG. 5  is a schematic view of a light source and the UV cut filter;  
         [0024]      FIG. 6  is an exploded perspective view of a color wheel and a UV cut filter according to another embodiment of the present general inventive concept; and  
         [0025]      FIG. 7  is a schematic view of a light source and a UV cut filter according to a conventional optical engine apparatus.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures.  
         [0027]     As shown in  FIGS. 1 and 2 , an optical engine device may include a light source  10  generating light; a DMD panel  3  used as a display device on which the light emitted from the light source  10  is projected to form an image beam; and a projector  5  magnifying and projecting the image beam generated by the display device  3  to a screen of a projection television.  
         [0028]     Here, the light source  10  is seated on a base  1 , and an optical unit accommodation casing  2  is placed behind the light source  10  and coupled to the base  2 . The optical unit accommodation casing  2  accommodates various optical engine components such as a color wheel assembly  20  having a color wheel selectively sorting the light from the light source  10  by light of red (R), green (G) and blue (B), an illuminator  4  uniformizing the light passed through the color wheel assembly  20  and transforming a path of the uniformized light toward the display device  3 , and so on.  
         [0029]     The light source  10  may include a lamp assembly  11  emitting light and a lamp assembly cover  12  covering the lamp assembly  11 . The lamp assembly  11  may include a lamp main body  16  generating the light; a first and a second lamp supporters  14  and  15  respectively placed in front and behind the lamp main body  16  and supportably coupled to the lamp main body  16 ; and a lamp support housing  13  supportably seating the first and the second lamp supporters  14  and  15  and the lamp main body  16  to which the first and the second lamp supporters  14  and  15  are coupled on the base  1 .  
         [0030]     The lamp main body  16  may include a bulb  17  (see  FIG. 5 ) as a light source generating light; and a reflection mirror  18  reflecting the light from the bulb  17  to guide a traveling path of the light.  
         [0031]     The bulb  17  may be replaced with an arc discharge lamp such as a mercury lamp, a metal halide lamp and a xenon lamp, etc.  
         [0032]     The reflection mirror  18  is hemispherically shaped, and coupled to the bulb  17  by surrounding it while leaving a front portion of the reflection mirror  18  opened so that the light from the bulb  17  can be passed therethrough and transmitted to a UV cut filter  40  (to be described later). The reflection mirror  18  may be shaped like an oval having a position of the bulb  17  as a first focus point and another position to which the light is focused as a second focus point, or may be a parabolic reflection mirror having a position of the bulb  17  as the first focus point so that the light emitted from the bulb  17  can be parallelly reflected.  
         [0033]     Meanwhile, the bulb  17  of the lamp main body  16  emits unwanted ultra violet (UV) rays and infrared radiation (IR), which are useless to form an image, and the ultra violet rays are cut by an IR protection filter coated over an inner surface of the reflection mirror  18 , and the infrared radiation is cut by an optical UV cut filter  40 .  
         [0034]     In other words, the UN cut filter  40  is provided in a path between the light source  10  and the color wheel assembly  20 , and filters the light from the light source  10  allowing visible rays to be passed therethrough while reflecting the ultra violet rays back to the lamp main body  16 .  
         [0035]     As illustrated in  FIG. 3 , the optical UV cut filter  40  is inclinedly coupled to an optical filter mounting part  21  provided to a side of the color wheel assembly  20 , and supported by an optical filter supporting bracket  30  coupled to the color wheel assembly  20 .  
         [0036]     The optical UV cut filter  40  protects the color wheel from damage by filtering the light from the bulb  17  so as to allow the visible rays to be transmitted to the color wheel, and reflects the UV rays back to the reflection mirror  18  of the lamp main body  16 .  
         [0037]     As illustrated in  FIG. 3 , the optical filter mounting part  21  provided on the side of the color wheel assembly  20 , as well as the side itself, has an inclined surface  23  sunken and inclined at a given angel. The inclined surface  23  is inclined downward (or upward) so that the UV cut filter  40 , coupled to the optical filter mounting part  21  and cohered to the inclined surface  23 , can project the ultra violet rays reflected by the UV cut filter  40  to a lower portion of the reflection mirror  18 , as shown in  FIG. 5 . In other words, an upper portion of the UV cut filter  40  is inclined toward the light source  10  and the lower portion of the UV cut filter  40  is inclined away from the light source  10 . Although the UV cut filter  40  is inclined downward (or upward) as shown in  FIG. 5 , the UV cut filter  40  may be inclined to a left or right direction with respect to a traveling line of the light from the light source  10  while being inclined downward (or upward).  
         [0038]     The optical filter supporting bracket  30  is placed in front of the UV cut filter  40  and coupled to the optical filter mounting part  21  by coupling members  22 ,  31  and  32  to support the UV cut filter  40  accommodated at the optical filter mounting part  21 .  
         [0039]     The coupling members  22 ,  31  and  32  comprise a coupling boss  22  having a screw head and provided in the optical filter mounting part  21 ; a coupling hole  31  formed penetrating through the optical filter supporting bracket at a position corresponding to the coupling boss  22 ; and a screw  32  coupled to the coupling boss  22  through the coupling hole  31  and screwing the optical filter supporting bracket  30  to the optical filter mounting part  40 .  
         [0040]     In the optical engine apparatus with the foregoing configuration, the UV cut filter  40  is installed at a side of the color wheel assembly  20  following a method described hereinafter.  
         [0041]     First, as illustrated in  FIGS. 3 and 4 , the UV cut filter  40  is mounted to the optical filter mounting part  21  formed in the side of the color wheel assembly  20 . Here, the UV cut filter  40  is accommodated at the inclined surface  23  of the optical filter mounting part  21  so as to be inclined downward (or upward) due to the inclined surface  23 , which is also inclined downward (or upward). The optical filter supporting bracket  30  is screwed to the optical filter mounting part  21  by using the coupling members  22 ,  31  and  32  to place the optical filter supporting bracket  30  in front of the UV filter mounting part  21 . In other words, the coupling holes  31  of the optical filter supporting bracket  30  are provided to communicate with the coupling boss  22  of the optical filter mounting part  21 , and each screw  32  is inserted into the respective coupling hole  32  to screw the optical filter supporting bracket  30  to the coupling boss  22 .  
         [0042]     As shown in  FIG. 5 , if the UV cut filter  40  is inclined downward (or upward), the visible ray in the light emitted from the bulb  17  of the light source  10  are passed through the UV cut filter  40  and transmitted to the color wheel, and the IR is blocked by the IR protection filter coated over the inner surface of the reflection mirror  18 , and reflected to the reflection mirror  18  by the UV cut filter  40 . Herein, the UV cut filter  40  inclined downward (or upward) and thus the UV rays reflected back to the reflection mirror  18 , are not converged onto the bulb  17 , but converged at a lower portion of the reflection mirror  18  centering on the bulb  17 . Therefore, temperature in the lower portion of the reflection mirror  18  is balanced to the temperature in an upper portion of the reflection mirror  18  which is heated to a relatively high temperature. Accordingly, the balanced temperature distribution between the upper and the lower portions of the reflection mirror  18  preserves the light source  10  in a stable condition, thereby enhancing quality and extending life expectancy of the light source  10 . Further, as described the above, the UV rays are not converged onto the bulb  17 , and thus the bulb  17  does not incidently stop working due the converged UV rays.  
         [0043]     Meanwhile, according to the foregoing embodiment, the UV cut filter  40  is inclined downward (or upward), but it may be inclined leftward or rightward, as shown in  FIG. 6 . Hereinafter, repeated descriptions related to the foregoing embodiment and its configurational aspects will be skipped.  
         [0044]     As shown in  FIG. 6 , on a side of a color wheel assembly  20   a  is formed an optical filter mounting part  21   a  inclined leftward or rightward, and a UV cut filter  40   a  is mounted therein. In more detail, an optical filter supporting bracket  30   a  placed in front of the optical filter mounting part  21   a  is coupled to the optical filter mounting part  21   a  by coupling members comprising a coupling boss  22   a  provided in the optical filter mounting part  21   a  and having a screw head; a coupling hole  31   a  formed in the optical filter supporting bracket  30   a  with respect to the coupling boss  22   a ; and a screw  32   a  screwed to the coupling boss  22  to couple the optical filter supporting bracket  30   a  to the optical filter mounting part  21   a.    
         [0045]     If the UV cut filter  40   a  adhered to the inclined surface of the optical filter mounting part  21   a  and inclined leftward or rightward while being coupled to the optical filter supporting bracket  30   a , the UV ray is reflected back to the reflection mirror  18  by the UV cut filter  40   a.  Herein, the reflected UV rays are not converged onto the bulb  17  but converged onto a portion in the reflection mirror  18 , which is separated from the bulb  17 , and thereby preventing the bulb  17  from being damaged due to the converged UV ray.  
         [0046]     According to the embodiments, the UV cut filter  40  is inclined downward (or upward), or leftward (or rightward), but not limited thereto. The UV cut filter may be inclined toward various directions as long as the UV ray is not converged onto the bulb when the UV cut filter reflects the UV ray back to the reflection mirror.  
         [0047]     Further, according to the embodiments, the UV rays are cut by the IR protecting filter formed inside the reflection mirror, and the optical filter may be replaced with the UV cut filter cutting the UV ray only, a UV/IR cut filter cutting both of the UV ray and IR both, or an IR cut filter cutting the IR.  
         [0048]     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.