A TV-set having screen covering means

Abstract: Between the picture screen and a front glass of a TV-set is arranged a curtain system for covering the screen when the set is not in use. The curtain opens automatically in response to the set being switched on, though with such delay that it is not opened until the picture has been fully established. When the set is switched off the curtain is actuated to be closed, and only thereafter the set it­ self will be switched off.

Description: The present invention relates to a television set with a cabinet and a cover element connected therewith, the cover element being positionable over the front of the picture screen. Especially years ago it was quite common that television sets had a roll-front cabinet, and by that means it was possible to shut off the picture screen when not in use. Such an arrangement is for example disclosed by United States Patent US-A- 2 737 649. When the television is not being used the set is left with a dull grey picture screen, which is architectonically undesirable both in relation to a desired attractive appearance of the set itself and also by insistently reminding the people present in the room of the presence of the set. In a sense the said roll-front cabinet was an excellent means of facilitating the opening up and shutting off the screen as desired, but in general this as well as similar cover arrangements have been abandoned, e.g. simple doors in front of the picture tube, because there is no special user demand for the presence of such devices. The users have gradually accepted the visual presence of the picture screen, also when in its switched off mode it only has a dull grey appearance; even when given the possibility of closing a screen cover element, the users generally do not utilize this facility. The users have additionally and accordingly got used to accepting that when switching the set on or off certain picture distortions occur. By the present invention it has been realized that the user will not necessarily have to take any action to achieve a desirable covering of the dull, idle picture screen, nor will be compelled to accept having to look at an underqualified picture at the beginning and ending of the periods of use of the set. According to the invention an apparatus can be provided which automatically ensures covering up the picture screen depending on whether or not the set is actually in use, i.e. purely electrically controlled. A cover arrangement for the picture screen may well be controlled depending on the set being switched on and off, respectively. According to the invention it is even possible to arrange this control such that the cover arrangement after switch-on of the set does not open till the picture has been perfectly established, respectively that the covering be activated immediately at switch-off while the fading of the picture is automatically delayed until the covering has been completed, such that the user at switch on and off of the set will not experience the incorrect picture reproduction occurring during the respective initial and final phases. In the same way as in a cinema with a screen curtain the user will experience that a fully established picture is shown from the start, just as it is a full and undistorted picture that is covered at the end. In addition it will be achieved that the picture screen is kept covered up whenever the television set is not in use, as the cover arrangement is activated in immediate or automatic response to the user's operation of the set only to switch this set on or off, i.e. the user does not have to attend especially to activating the cover arrangement. The set can comprise time delay means or sensors for the appearance of a "normal picture" after the set has been switched on, such that when switched on the screen is not uncovered until the picture has become fully established, while correspondingly the set is not caused to be switched off until the cover arrangement has managed to completely cover the picture screen. The user will thus always experience a perfect picture also in the switch-on/off phases, also achieving that the dull, grey screen will be covered any time the set is not in use, without the user having to take other action than the usual switching on and off the set, i.e. without any special attention to the operation of the cover arrangement. The known roll-front or even corresponding doors may well constitute the cover arrangement of the present invention provided the relevant arrangement can be electrically activated. This, however, will cause various obvious inconveniences and according to a preferred embodiment of the invention a roller blind system is placed in the space between the picture screen and a front glass of the set, preferably in the form of two roller blinds which can be drawn horizontally from either side similarly to a partition curtain across a theatre stage or a cinema screen. The curtain fabric or sheet is in no way required to imitate a furniture front, but may have any reasonable design as a neutral or decorative cover element, all except dull grey. By the application of a partition curtain which is parted and gathered at the centre of the picture screen a harmonious symmetrical effect at the opening and closing operation will be implied, and moreover a comparatively fast opening can be achieved, which may be adapted to a comparatively short heating time of the picture tube. By a preferred moving mechanism for the partition curtain as described below it suffices to use a relatively small motor, and the entire curtain arrangement can be embodied in a simple and inexpensive manner. The invention which is further defined in the claims, is described in more detail in the following with reference to the drawing in which:- Fig. 1 is a schematic perspective view of a picture tube having a cover arrangement according to the invention, Fig. 2 is the same as seen from above and Fig. 3 is a detailed view of the lower end of a rewinding cylinder as used in the arrangement. In Fig. 1 is shown a picture tube 2, in front of which, on carrying parts not shown in a TV-cabinet, is placed a cover arrangement comprising a dividing curtain consisting of two curtain pieces 4 mounted on respective vertical cylinders 6 at opposite sides of the picture tube screen 8. Each of the cylinders 6 is coupled up with a central shaft 10 which at the top and bottom has a driving wheel 12 which by respective belt drives 14 is connected with respective pulleys 16 close to the vertical centre plane of the screen 8, but naturally placed a little above and a little below this, respectively. Through a gear box 18 the lower wheels can be driven in mutually opposite directions by means of a reversible motor 20. The free edges of the curtain pieces 4 are fastened to vertical supporting bars 22, each having respective upwardly and downwardly protruding parts 24, by which they are secured to the outer run of the respective belts 14. As shown in Fig. 2 the arrangement concerned is situated in the space between the picture screen 8 and a front glass 26 of the TV-cabinet. When the television set is turned off the curtain edges on the bars 22 are drawn tightly together at the centre of the picture screen 8 such that the screen be dimmed. The motor 20 is connected with a control unit not shown which after a certain lapse of time after switching on the set activates the motor 20 to drawing the curtain edges away to their respective sides while simultaneously rolling up the curtain pieces on the cylinders 6; the actual time delay is comparatively short as it only has to suffice for the picture at the screen to establish itself in good quality. When the set is switched off the control unit ensures that the first reaction to the switching off is that the motor 20 be activated to drawing the curtains across the screen and that the actual switching off with resulting brief picture deformation does not happen till after the curtain has been closed. It might, however, be acceptable that the turning off the set be effected simultaneously with the drawing the curtains. By the shown detailed arrangement, where the motor 20 provides both for moving the free edges of the curtain pieces 4 and for bringing about the related turnings of the rewinding cylinders 6 for winding and unwinding these pieces, the motor may be comparatively small as there will be no significant resistance to the movements. However, it may present a problem that the linear motion of the front edges of the curtains does not fully correspond to the speed by which the pieces are wound onto or unwound from the cylinders 6 is during winding or unwinding the winding diameter of the cylinders changes significantly. If it is desired to keep the curtain pieces taut, this problem, however, can easily be overcome by providing a resiliently yielding connection either between the drawing belts 14 and the related end parts 24 of the bars 22 or between the shafts 10 and the respective rewinding cylinders 6. The latter solution is illustrated in Fig. 3 where the cylinder 6 is shown drive connected to the shaft by a torsion spring 28 facilitating the required mutual motion during constant stretching of the associated piece of curtain. In Fig. 1 is schematically shown an on/off switch unit 26 for the TV-set and an associated delay unit 28, from which the motor 20 is energized with a required delay after 'ON' actuation for opening the curtain when the picture is ready. By 'OFF' actuation the motor 20 is energized immediately for closing the curtain, and then the TV-set is switched off when the curtain has been closed. In connection with the switching on of the set it is possible to detect electronically the establishing of a full and fully energized picture on the screen, and in that case the unit 28 may represent a detector for this purpose.

Claims: A television set with a cabinet and a cover element connected therewith, said cover being positionable over the front of the picture screen for covering the same when the set is not in use, the set being provided with control means for automatic motion of the cover element between its respective covering and uncovering positions in response to actuation of associated switch means; characterized in that the cover element (4) is placed in the space between the picture screen (8) and a front glass (26) in the cabinet and is constituted by roller blind or curtain means (4) mounted on rewinding means (6) outside the outer edge of the picture screen. A television set according to claim 1, characterized in that the control means (28) are designed so as to actuate, in response to the switching on the set, the removal of the cover element (4) from the screen with such a delay that the actuation is initiated only after the screen picture having been fully established. A television set according to claim 1 or 2, characterized in that the control means (28) are designed to respond to a switching off the set by first actuating the cover element (4) to be moved into its closed position and then causing the set to be switched off. A television set according to claim 1, characterized in that means (20, 16, 18, 14) are provided for motor driven motion both of the free curtain edge (22) inwardly over and away from the picture screen and of related means (6) for rolling the curtain out and up, respectively. A television set according to claim 4, characterized in that the curtain is divided into two parts (4), each half of it being connected with associated rewinding means (6) at either side of the picture screen. A television set according to claim 4 or 5, characterized in that there are inserted resiliently yielding members (28) in the drive connection between the driving means and either the free curtain edge(s) (22) or the respective rewinding means (6). A television set according to claim 6, characterized in that the resiliently yielding members are constituted by a torsion spring (28) inserted between the drive means (10) and the rewinding means (6).

Inventors: SKOVGAARD ALLAN, SKOVGAARD, ALLAN
Applicants: BANG & OLUFSEN AS, BANG & OLUFSEN A/S
Application year: 1989
Main classification: H04N5
IPC codes: H04N5