Television signal display apparatus

Abstract: A television signal display apparatus of the present invention includes a main picture quality adjustment value memory for storing a picture quality adjustment value set according to viwer's preference; a sub picture quality adjustment value memory for storing a picture quality adjustment value preliminarily set for every aspect ratio; a microcomputer for calculating an optimum picture quality adjustment value for a new aspect ratio from the picture quality adjustment values read from the main and sub picture quality adjustment value memories, setting the optimum picture quality adjustment value in a picture quality adjusting circuit and making an aspect ratio selecting circuit work. When the aspect ratio is changed, the viewer can watch a picture having the same picture quality as before and having no incongruity due to a picture quality difference produced by aspect ratio selection even for so dark picture as ABL does not work.

Description: BACKGROUND OF THE INVENTION The present invention relates to a color television signal display apparatus having a function to compensate picture quality variation due to aspect ratio selection. When an aspect ratio of a picture is changed, as long as a picture quality adjustment value of a television receiver is not changed, an anode current per unit area of picture on a cathode ray tube (CRT, hereafter) is small for a large screen size. Accordingly, the picture has sometimes been felt to be darker in brightness, lower in color saturation or lower in contrast than viewer's desire. For example, Japanese Patent Laid-Open 5-183834 is proposed as a countermeasure. That is, ABL limiting resistors are selected or a plurality of picture quality adjustment values are set according to viewer's desire and the picture quality adjustment value can be selected out of the picture quality adjustment values. The function of aspect ratio selection is explained below, referring to drawings. FIG. 4 is a block diagram of an ABL selecting circuit in accordance with the prior art. The symbol 111 is a CRT. The symbol 112 is a flyback transformer (FBT, hereafter). The symbols 113 and 114 are ABL limiting resistors to limit an anode current of CRT 111. The symbol 115 is a diode for ABL clamping. The symbol 116 is an ABL limiting resistor selecting switch for changing a limiting value of an anode current due to ABL action by short circuiting ABL limiting resistor 114. The function of an ABL selecting circuit in accordance with the prior art configured like the above is explained below, referring to FIG. 4. In FIG. 4, when a picture is displayed with a 4:3 aspect ratio, ABL limiting resistor selecting switch 116 is in an off-position and the resistance of the ABL limiting resistor is a summation of the resistances of ABL limiting resistors 113 and 114. As a result, the anode current limited by ABL action is set small. When a picture is displayed with a 16:9 aspect ratio, ABL limiting resistor selecting switch 116 is in an on-position and the resistance of the ABL limiting resistor is a resistance of only ABL limiting resistor 113. As a result, the anode current limited by ABL action is set to a larger value than the value at 4:3 aspect ratio. Thus, the maximum anode current of a CRT when a bright picture is displayed with a 16:9 aspect ratio can be made larger than that when displayed with a 4:3 aspect ratio and the anode current per unit area of picture can be made nearly constant even if the aspect ratio varies. However, these countermeasures are for a case when the ABL circuit works at a comparatively bright picture but when the picture is comparatively dark the ABL circuit does not work, and the effect is unexpected. Further, viewers must manually select for a good performance such as color saturation, picture sharpness, etc. EP-A-0606855 discloses a television display apparatus comprising: aspect ratio selecting command means for outputting an aspect ratio selecting command signal to select an aspect ratio of a displayed picture; picture quality adjustment value storing means for storing a picture quality adjustment value preliminarily set to get a picture quality corresponding to various kinds of aspect ratios of picture; aspect ratio selecting process means for outputting an aspect ratio selecting signal which varies the aspect ratio of the displayed picture to an aspect ratio selecting means by said aspect ratio selecting command signal outputted from said aspect ratio selecting command means, for reading out a picture quality adjustment value corresponding to an aspect ratio to be selected from said picture quality adjustment value storing means, and for outputting a picture quality selecting signal to select a picture quality adjustment value of the displayed picture to a picture quality adjusting means; picture quality adjusting means for selecting a picture quality adjustment value by a picture quality selecting signal outputted from said aspect ratio selecting process means; and aspect ratio selecting means for selecting an aspect ratio of the picture by an aspect ratio selecting signal outputted from said aspect ratio selecting process means, wherein said aspect ratio selecting command means comprises: first aspect ratio selecting command means for outputting a first command signal to select an aspect ratio of a displayed picture by an aspect ratio selecting command from a viewer. An article by Nakagaki et al entitled "Wide Aspect TV Receiver with Aspect Detection and Non-Linear Control for Picture Quality" published in IEEE Transactions on Consumer Electronics, Vol 40, No. 3 at pages 743-751 discloses controlling picture quality automatically in a non-linear way using FUZZY-inference. Summary of the Invention The present invention provides a television signal display apparatus comprising: aspect ratio selecting command means for outputting an aspect ratio selecting command signal to select an aspect ratio of a displayed picture; picture quality adjustment value storing means for storing a picture quality adjustment value preliminarily set to get a picture quality corresponding to various kinds of aspect ratios of picture; aspect ratio selecting process means for outputting an aspect ratio selecting signal which varies the aspect ratio of the displayed picture to an aspect ratio selecting means by said aspect ratio selecting command signal outputted from said aspect ratio selecting command means, for reading out a picture quality adjustment value corresponding to an aspect ratio to be selected from said picture quality adjustment value storing means, and for outputting a picture quality selecting signal to select a picture quality adjustment value of the displayed picture to a picture quality adjusting means; picture quality adjusting means for selecting a picture quality adjustment value by a picture quality selecting signal outputted from said aspect ratio selecting process means; and aspect ratio selecting means for selecting an aspect ratio of the picture by an aspect ratio selecting signal outputted from said aspect ratio selecting process means, wherein said aspect ratio selecting command means comprises: first aspect ratio selecting command means for outputting a first command signal to select an aspect ratio of a displayed picture by an aspect ratio selecting command from a viewer; characterised in that the aspect ratio selecting command means further comprises: second aspect ratio selecting command means for outputting a second command signal to select an aspect ratio of a displayed picture by an aspect ratio discriminating signal included in an input signal; in that the picture quality adjustment value storing means comprises: main picture quality adjustment value storing means for storing a main picture quality adjustment value set by a picture quality adjusting signal from a viewer; and sub picture quality adjustment value storing means for storing a sub picture quality adjustment value preliminarily set at a production line and the like of a television signal display apparatuses; and in that the aspect ratio selecting process means comprises: means for calculating said main picture quality adjustment value read out from said main picture quality adjustment value storing means and said sub picture quality adjustment value read out from said sub picture quality adjustment value storing means and calculating a picture quality adjustment value suitable for a viewer's desire even in a picture having a new aspect ratio; means for outputting a picture quality selecting signal set to said newly calculated picture quality adjustment value to said picture quality adjusting means; and means for outputting an aspect ratio selecting signal to vary the aspect ratio of the displayed picture to an aspect ratio selecting means by said first or second command signal from said aspect ratio selecting command means. By providing with the above configuration, the television signal display apparatus can always automatically adjust the picture quality so as to get an optimum picture quality for a new aspect ratio at every aspect ratio selection. Furthermore, an optimum picture quality for viewer's desire can be automatically obtained due to the addition of a memory to store various kinds of picture quality adjustment values set by the viewer in the above-described configuration and determining the new picture quality adjustment values considering these picture quality adjustment values at every aspect ratio selection. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a main part which automatically adjusts a picture quality variation due to aspect ratio selection in a television signal display apparatus in accordance with an example of the present invention. FIG. 2 is a block diagram of a main part which automatically adjusts a picture quality variation due to aspect ratio selection in a television signal display apparatus in accordance with a preferred embodiment of the present invention. FIG. 3 is a flow chart showing a function of a circuit which automatically adjusts a picture quality variation due to aspect ratio selection in a television signal display apparatus in accordance with a preferred embodiment of the present invention. FIG. 4 is a circuit diagram of an ABL selecting circuit which compensates a picture quality variation due to aspect ratio selection in accordance with the prior art. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a block diagram of a main part which automatically adjusts a picture quality variation due to aspect ratio selection in a television signal display apparatus in accordance with an example of the present invention. In FIG. 1, an aspect ratio selecting command signal 6 which is an output signal from an aspect ratio selecting command means 1 is supplied to an aspect ratio selecting process means 2. Aspect ratio selecting process means 2 supplies an aspect ratio selecting signal 8 to an aspect ratio selecting means 4 and at the same time, supplies an information read from a picture quality adjustment value storing means 5 storing picture quality adjustment values to a picture quality adjusting means 3 as a picture quality selecting signal 7. The function of a television signal display apparatus configured as above is explained below, referring to FIG. 1. In FIG. 1, when an aspect ratio selecting command signal 6 outputted from an aspect ratio selecting command means 1 is inputted to an aspect ratio selecting process means 2, aspect ratio selecting process means 2 outputs an aspect ratio selecting signal 8 to an aspect ratio selecting means 4 and selects an aspect ratio of a picture to be displayed on a CRT and at the same time, reads out a picture quality adjustment value corresponding to an aspect ratio newly selected from a picture quality adjustment storing means 5 storing picture quality adjustment values preliminarily set at for example, a production process of television signal display apparatuses and outputs a picture quality selecting signal 7 through a D/A converter or a bus line (both are not shown) and sets the picture quality adjustment value read out from picture quality adjustment value storing means 5 in picture quality adjusting means 3. Thus, viewers can watch a picture without noticing any picture quality variation due to aspect ratio difference at every aspect ratio selection. The adjustment of the picture quality adjustment values stored in picture quality adjustment value storing means 5 is different from the adjustment of only the brightness by selecting an ABL limiting resistor in the prior art and can arbitrarily select brightness, contrast, color saturation, hue, picture sharpness, etc. Thus, the present invention presents a television signal display apparatus which can always automatically display an optimum picture quality, independent of its aspect ratio. FIG. 2 is a block diagram of a main part which automatically adjusts a picture quality variation due to aspect ratio selection in a television signal display apparatus in accordance with a preferred embodiment of the present invention. An aspect ratio selecting command signal 61 is outputted from first aspect ratio selecting command means 11 commanding to select an aspect ratio. Another aspect ratio selecting command signal 62 is outputted from second aspect ratio selecting command means 12 commanding to select an aspect ratio by an aspect ratio discriminating signal obtained from an input signal, for example, an ED-2 signal (ED is a short form of Extended Definition and ED-2 is a kind of new television system in Japan) or a television signal outputted from a VCR (Video Cassette Recorder). The aspect ratio selecting command signals 61 and 62 are supplied to a microcomputer 21 working as aspect ratio selecting process means. The microcomputer 21 supplies an aspect ratio selecting signal 8 and a picture quality selecting signal 7 to aspect ratio selecting means 41 and picture quality adjusting means 31, respectively. A picture quality adjusting signal 9 used for setting a picture quality by the viewer is inputted to microcomputer 21. A main picture quality adjustment value storing means 51 storing a main picture quality adjustment value set by the viewer and sub picture quality adjustment value storing means 52 storing a sub picture quality adjustment value preliminarily set, for example, at a production line of television signal display apparatuses are connected to microcomputer 21. The function of a television signal display apparatus configured like the above is explained below, referring to FIGs. 2 and 3. Step 1: Aspect ratio selecting command signal 61 or 62 is inputted to microcomputer 21. Step 2: Microcomputer 21 discriminates a new aspect ratio inputted. Step 3: Microcomputer 21 supplies an aspect ratio selecting signal 8 to aspect ratio selecting means 41. Step 4: Microcomputer 21 selects an aspect ratio of the picture. Step 5: At the same time, microcomputer 21 reads out from main picture quality adjustment value storing means 51 a main picture quality adjustment value of the picture of which picture quality was set by the viewer and has been watched by the viewer, before selecting an aspect ratio. Step 6: Microcomputer 21 reads out from sub picture quality adjustment value storing means 52 a sub picture quality adjustment value of the picture according to the aspect ratio newly set. Step 7: Microcomputer 21 works as operation means for calculating a new picture quality adjustment value from the picture quality adjustment values read out just before and produces a new picture quality adjustment value according to viewer's preference for a picture having a new aspect ratio. Step 8: Microcomputer 21 outputs a picture quality selecting signal 7 through a D/A converter or a bus line (both are not drawn). Step 9: Microcomputer 21 sets the new picture quality adjustment value produced at step 7 in picture quality adjusting means 31. Thus, viewers can watch a picture in the picture quality according to their preference for any aspect ratio without noticing any picture quality variation due to aspect ratio difference at every aspect ratio selection without any manual adjustment by them. Thus, the present invention presents a television signal display apparatus which can automatically display an optimum picture quality according to the viewer's preference and independent of its aspect ratio. It is obvious that a television receiver is included in a television signal display apparatus described above.

Claims: A television signal display apparatus comprising: aspect ratio selecting command means (1) for outputting an aspect ratio selecting command signal (6) to select an aspect ratio of a displayed picture; picture quality adjustment value storing means (5) for storing a picture quality adjustment value preliminarily set to get a picture quality corresponding to various kinds of aspect ratios of picture; aspect ratio selecting process means (2) for outputting an aspect ratio selecting signal (8) which varies the aspect ratio of the displayed picture to an aspect ratio selecting means (4) by said aspect ratio selecting command signal (6) outputted from said aspect ratio selecting command means (1), for reading out a picture quality adjustment value corresponding to an aspect ratio to be selected from said picture quality adjustment value storing means (5), and for outputting a picture quality selecting signal (7) to select a picture quality adjustment value of the displayed picture to a picture quality adjusting means (3); picture quality adjusting means (3) for selecting a picture quality adjustment value by a picture quality selecting signal (7) outputted from said aspect ratio selecting process means (2); and aspect ratio selecting means (4) for selecting an aspect ratio of the picture by an aspect ratio selecting signal (8) outputted from said aspect ratio selecting process means (2), wherein said aspect ratio selecting command means (1) comprises: first aspect ratio selecting command means (11) for outputting a first command signal (61) to select an aspect ratio of a displayed picture by an aspect ratio selecting command from a viewer; characterised in that the aspect ratio selecting command means (1) further comprises: second aspect ratio selecting command means (12) for outputting a second command signal (62) to select an aspect ratio of a displayed picture by an aspect ratio discriminating signal included in an input signal; in that the picture quality adjustment value storing means (5) comprises: main picture quality adjustment value storing means (51) for storing a main picture quality adjustment value set by a picture quality adjusting signal from a viewer; and sub picture quality adjustment value storing means (52) for storing a sub picture quality adjustment value preliminarily set at a production line and the like of a television signal display apparatuses; and in that the aspect ratio selecting process means (2, 21) comprises: means for calculating said main picture quality adjustment value read out from said main picture quality adjustment value storing means (51) and said sub picture quality adjustment value read out from said sub picture quality adjustment value storing means (52) and calculating a picture quality adjustment value suitable for a viewer's desire even in a picture having a new aspect ratio; means for outputting a picture quality selecting signal (7) set to said newly calculated picture quality adjustment value to said picture quality adjusting means (3, 31); and means for outputting an aspect ratio selecting signal (8) to vary the aspect ratio of the displayed picture to an aspect ratio selecting means (4, 41) by said first or second command signal (61, 62) from said aspect ratio selecting command means (1, 12, 13). A television signal display apparatus as recited in claim 1, wherein an adjusting factor of a picture quality adjustment value stored in the picture quality adjustment value storing means (5) comprises at least one of brightness, contrast, color saturation, hue and picture sharpness of a displayed picture.

Inventors: YOSHIMI OSAMU, YOSHIMI, OSAMU
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1996
Main classification: H04N5
IPC codes: H04N5