Abstract:
In the case of a food processor ( 1 ) having a base unit ( 2 ) and having a work container ( 40 ) that can be placed on a housing wall ( 3 ) of the base unit ( 2 ), and having a cover ( 47 ) for the work container ( 40 ), retaining means ( 55 ) for retaining both the work container ( 40 ) on the base unit ( 2 ) and the cover ( 47 ) on the work container ( 40 ) are provided, wherein the retaining device (55) comprises at least one retaining member ( 70, 71 ) provided on the inside of the cover ( 47 ) and a retaining member ( 57 ) provided on a shaft configuration ( 9 ) comprising a drive shaft ( 10 ).

Description:
FIELD OF INVENTION  
       [0001]     This invention relates to a high brightness scrolling colour display system. In particular, this invention relates to a liquid crystal colour projection system.  
       BACKGROUND OF INVENTION  
       [0002]     A scrolling colour projector, such as described in “Single Panel Reflective LCD Projectors”, by Volke Blume, in Displaytechnik, Fernseh- und Kino-Technich, no. 1-2/2002, produces full colour images from a single light modulator, such as a liquid crystal on silica (LcoS) panel, by illuminating the panel with multiple stripes of coloured light (red, green, blue) that continuously scroll, from top to bottom, over the liquid crystal panel.  
         [0003]     American patent no. U.S. Pat. No. 6,540,362 discloses a scrolling colour projection system having an increased number of red, green and blue scrolling colour stripes achieved by a lenticular lens array and a second lens array for collimating the plurality of stripes. The collimated stripes are scrolled over the liquid crystal panel by using rotating prisms.  
         [0004]     Further, American patent application no. US 2002/0191154 discloses a single panel colour liquid crystal display (LCD) projector, shown in  FIG. 1   a . The LCD projector system  100  utilising a scrolling colour system, wherein un-polarized light is split into constituent red, green and blue coloured light beams, and which LCD projection system  100  comprises a light source  102 , colour separating means  104 , a substantially non-absorptive polarizing element  106 , a polarizing beam splitter  108 , a light valve or modulator  110 , and a projection lens  112 . The light valve or modulator  110  is adapted to receive incident light and to impress a desired image upon the incident light, which image is then projected by the projection lens  112 . The colour separating means  104  comprises dichroic colour filters  114 ,  116 ,  118  and  120 , prisms  122 ,  124  and  126 , and the reflecting mirrors  128  and  130 . The colour separating means  104  generate scrolling and coloured light beams by rotating the prisms  122 ,  124  and  126 .  
         [0005]     The phase and rotation of the prisms  122 ,  124  and  126  are important, because each stripe of coloured light must be projected and scrolled on the light valve or modulator  110  at specific times in relation to video information (electrical scan) that is also provided to the light valve or modulator  110 . That is, the red, green and blue stripes of light must be present on a line of the display concurrently with the presentation of the corresponding video information.  
         [0006]     The American patent no. U.S. Pat. No. 6,540,362, the American patent application no. U.S. Pat. No. 2002/0191154 and the article entitled “Single Panel Reflective LCD Projectors”, which are hereby incorporated in the present specification by reference, describe scrolling colour projection systems utilising red, green and blue colour stripes. In these types of projection systems, the red, green and blue colour beams are scrolled geometrically separated over the display panel, and as such setting requirements on the display panel size to obtain an efficient filling of the light path with the light that originates from the light source. This can best been explained using the etendue principles within projection systems, such as described. in “Optimized light sources for projection displays”, by H. Mönch et al, in Society for Information Display international symposium may 18-20, 1999, Digest of technical papers, Volume XXX, pp 1076-1079, (SID 99 Digest).  FIG. 1   b  shows the collectable lumen for a 100W, 1.0 mm arc UHP lamp as function of the etendue of the optical light path. On the x-axis the location of typical (3-panel based) projection systems are indicated for various panel sizes. Where in 3-panel projection systems the each individual panel is illuminated with one of the primary colours red, green and blue; in the scrolling colour projection systems these three coloured light areas are imaged on separated positions of one and the same panel. To obtain, however, the same amount of collected lumens from the light source, the total display area that is illuminated with light needs in the single panel system the same as in the 3-panel systems; meaning that a three 0.7″ panel projection system will use the same amount of collected lumens from the light source than a √{square root over (3)}*0.7=1.2″ single panel scrolling colour projection system. Due to these etendue limitations of these prior art projection systems, single panel scrolling colour projection systems have the advantage that only 1 panel is required instead of 3, however at a √{square root over (3)} etendue penalty, meaning that either a lower system efficiency needs to be accepted at similar display size, or a √{square root over (3)} diagonal times larger panel needs to be applied to collect the same amount of lumens from the projection light source.  
       SUMMARY OF THE INVENTION  
       [0007]     It is an object of the present invention to provide a multiple primary scrolling colour system, which system increases usable etendue of a projection lamp without increasing the size of a display panel.  
         [0008]     A particular advantage of the present invention is the provision of a system having expanded colour gamut.  
         [0009]     This object is obtained according to a first aspect of the present invention having characterizing features as described in the characterizing part of claim  1 .  
         [0010]     Further embodiments are obtained according to the first aspect of the present invention as described in dependent claims  2 - 19 . 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0011]     The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawing, wherein:  
         [0012]      FIG. 1   a , shows a block diagram of a prior art projection system,  
         [0013]      FIG. 1   b , shows a graph of the collectable lumen for a 100W, 1.0 mm arc UHP lamp as function of the etendue of the optical light path,  
         [0014]      FIG. 2 , shows an illumination window according a prior art projection system,  
         [0015]      FIG. 3 , shows an illumination window according to a first embodiment of the present invention,  
         [0016]      FIG. 4 , shows a graph: of colour space in a projection system, and  
         [0017]      FIG. 5 , shows the illumination window according to the preferred embodiment of the present invention utilising a series of filters. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0018]     In the following description of the various embodiments, reference is made to the accompanying drawing which form a part hereof, and in which are shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.  
         [0019]      FIG. 1  shows, as described above, a projection system  100 , which may be a scrolling colour liquid crystal on silicon(LcoS) projection system, and shows the rotating prisms  122 ,  124 ,  126  for generating a scrolling colour effect on an illumination window. By positioning slits  132 ,  134  and  136  before each rotating prisms  122 ,  124  and  126  sharp colour bars are obtained on the display panel. Each slit  132 ,  134  and  136  is illuminated by its corresponding colour red, green or blue and is imaged on a display panel through the prisms  122 ,  124  and  126 .  
         [0020]     A display panel in this context should be construed as a light valve means or light modulating means such as a transmissive liquid crystal display, a reflective liquid crystal on silicon or a reflective Micro Electrical Mechanical based display such as a DMD panel.  
         [0021]      FIG. 2 , shows an illumination window  200  as obtained by prior art system and projected on to a display panel. The illumination window  200  has red  202 , green  204  and blue  206  scrolling colour bars. The widths  208 ,  210 , and  212  of the respective slits  214 ,  216 , and  218  determines the widths of the colour bars  202 ,  204 , and  206 . The widths  208 ,  210 , and  212  are selected so as to generate exactly three colour bars  202 ,  204 , and  206  on the display panel. Coloured images are generated by writing each line in the display panel with new colour information as soon as a new colour starts to appear on the corresponding row in the display panel.  
         [0022]      FIG. 3 , shows an illumination window  300  projected on to a display panel, which illumination window  300  has six scrolling colour bars, namely a purple  302 , a red  304 , a yellow  306 , a green  308 , a cyan  310 , and a blue  312  colour bar. The six colour bars are generated by extending the widths  208 ,  210 , and  212 , shown in  FIG. 3  as extended widths  314 ,  316 ,  318   a  and  318   b . Hence slits  320 ,  322 , and  324  (where slit  324  is shown as two separate parts  324   a  and  324   b ) are wider than slits  214 ,  216 , and  218 , shown in  FIG. 2 , so that the red, green and blue colour bars  304 ,  308  and  312  partly overlap each other. The overlaps generate mixed colour bars namely purple  302 , yellow  306  and cyan  310 .  
         [0023]     Each pixel of the display panel is driven sequentially relative to time so that the total amount of light per colour balances the colour as required by each pixel. Since the red, green and blue colour bars  304 ,  308  and  312  cover a greater area of the display panel, the throughput of the light path is increased and a greater amount of light from the projector light source is collected and guided through the projection system thereby achieving a higher brightness. In case each of the red, green and blue colour bars  304 ,  308  and  312  covers  50 % of the display area, a 0.7″ 3-panel projection system will use the same amount of collected lumens from the light source than a √{square root over (2)}* 0.7=0.99″. This means that a projection system according to the present invention will approximately supply the same brightness with a 0.99″ display panel that a scrolling colour projection system using a 1.2″ display panel according to the prior art.  
         [0024]     According to the preferred embodiment of the present invention one of the slits  320 ,  322  and/or  324  allows a wider wavelength range to be channelled through to associated prisms  122 ,  124 , and/or  126 .  
         [0025]      FIG. 4 , shows a graph of colour space designated in entirety by reference numeral  400  in a projection system. The first set of colours (primaries red  402 , green  404  and blue  406 ) defines a complete span  408  of colour space of the projection system. The second set of colours (primaries cyan  410 , yellow  412  and purple  414 ) comprises primaries which generate high brightness values. The second set of colours are generated by combining the first set of colours, that is cyan=green+blue; yellow=red+green; and purple=blue+red.  
         [0026]     In prior art projection systems the full spectrum of the light source is generally not effectively utilised. Especially the spectral parts around the 500 nm (490 to 510 nm) and around the 600 nm (590 to 610 nm) is filtered away since these parts de-saturate the primary red, green and blue colours. However, since the projection systems according to the present invention generates mixed colour bars  302 ,  306 , and  310 (purple, yellow, and cyan), the wavelength ranges around 500 nm and around 600 nm may now be utilised in the cyan and yellow colour bars  306 ,  310 . Hence in the preferred embodiment the full 480 to 590 nm wavelength range is channelled through the green prism, the green colour de-saturates resulting in a green colour point with a low “y” value in the “x”-“y” colour space  400 . By adding filters, shown in  FIG. 5  as reference numerals  502 ,  504 , and  506 , before the green prism a compensation of the low “y” value is achieved. Thus a 490 to 580 nm wavelength range filtering is added for the Green colour bar  308 , pushing the “y”-value of the green primary  404  back to its desired value. A 480 to 510 nm wavelength range filtering is added for the yellow colour bar  306  and a 560 to 590 nm wavelength range filtering is added for the cyan colour bar  310 . The brightness of the yellow and cyan colour bars  306  and  310  is increased, while their colour points, shown in  FIG. 4  as reference numerals  410 ′,  412 ′,  414 ′, are pushed outside the old colour space  400  as defined by the red  402 , green  404  and blue  406  primary colours.  
         [0027]     According to an alternative embodiment of the present invention the cyan and yellow filter in the green slit, which filters also transmit parts of the complementary colours. That is, the cyan filter transmits part of the yellow and the yellow filter transmits part of the cyan. This pushes the points  410 ′,  412 ′ and  414 ′ back to original points  410 ,  412  and  414 , while the 480 to 510 mn and 560 to 590 nm wavelength ranges increase the brightness.  
         [0028]     In a further alternative embodiment of the present invention the system comprises wave guides for guiding the colours towards the predetermined positions in front of the prisms ( 122 ,  124  and  126 ).  
         [0029]     Where the preferred embodiment in this disclosure uses rotating prisms as scrolling means for sweeping colours over the display panel, the invention may in alternative embodiments comprise different types of scrolling means such as spinning wheels, rotating drums, rotating polygan mirrors, MEM based scanners, LCD based scanners and more.