(19)
(11) EP 1 569 196 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
14.12.2005 Bulletin 2005/50

(43) Date of publication A2:
31.08.2005 Bulletin 2005/35

(21) Application number: 05250788.6

(22) Date of filing: 11.02.2005
(51) International Patent Classification (IPC)7: G09G 3/36, G09G 3/34
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL BA HR LV MK YU

(30) Priority: 11.02.2004 GB 0403077

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Kadoma-city, Osaka 571-8501 (JP)

(72) Inventor:
  • Taylor, Richard, c/o Matsushita Electric (UK) Ltd
    Pentwyn Ind. Estate, Cardiff CF23 7XB (GB)

(74) Representative: Davies, Gregory Mark 
Urquhart-Dykes & Lord LLP Three Trinity Court, 21-27 Newport Road
Cardiff CF24 0AA
Cardiff CF24 0AA (GB)

   


(54) Liquid crystal display


(57) An LCD display device such as a television or computer monitor comprises an LCD display 10, and a photo sensor 15 for sensing the ambient lighting level within a room in which the display 10 is situated. The device further comprises an electronic circuit for analysing the video content of a picture being displayed on the display 10, and a control circuit connected to both the output of the photo sensor 15 and video analysing circuit 13. The control circuit determines the brightness of a back light 11 which illuminates the LCD display 10. The brightness of the back light is dependent on the ambient lighting levels and the video content of the picture and is varied accordingly so as to optimise the contrast of the displayed picture.






Search report