JPH04104581A - On-screen display circuit for color television receiver - Google Patents

Abstract

PURPOSE:To prevent an on-screen display from jutting out from a television screen by switching a count set value little by little with a vertical display counter responding to changeover output. CONSTITUTION:A detection circuit 7 is provided to detect whether or not the oscillation frequency of the oscillation frequency output of an oscillation circuit 6 is more than a prescribed value. The oscillation frequency of the oscillation frequency output for on-screen display from the oscillation circuit 6 is changed according to the horizontal size of a television screen 1. When this oscillation frequency is changed to be more than the prescribed value, the changeover output for the count set value is supplied against the vertical display counter from the detection circuit 7. On the other hand, when the vertical size is adjusted according to the horizontal size, since a vertical display counter 4 switches the count set value little by little according to the input of this changeover output, a vertical area detection point is adjusted to be a prescribed position at all times even when the vertical size is changed. Thus, the on-screen display can be prevented from jutting out from the television screen.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an on-screen display circuit in a color television receiver.

(Prior art and its problems) FIG. 3 is a diagram showing a conventional on-screen display circuit and a television screen. The TV screen in the same figure shows a circle image,
As an on-screen display, a square-shaped display indicating the volume level is shown. In addition, FIG. 4 shows a circle image formed by enlarging the horizontal size and vertical size of the circle image in FIG.
FIG. 7 is a diagram showing the bar-shaped display with the lower portion missing, and is a diagram for explaining the problem of the conventional circuit.

Referring to these figures, we will explain the on-screen display function of conventional color television receivers.
First of all, in most color television receivers, when you adjust the volume level with a remote control, for example, as shown on the TV screen l in Figure 3, a video signal is generated, for example, for convenience of explanation. It is equipped with a so-called on-screen display function that can display information on the current volume level corresponding to the adjustment operation in a predetermined area 3 along with an image 2 shown by a circle. .

Note that this predetermined area 3 varies depending on the on-screen display data; for example, if it is a selected channel, it is the upper right corner of the TV screen l, or if it is an off timer, it is the upper left corner of the TV screen 1. Although there are various examples such as a corner, in this specification, for convenience of explanation, as just one example, the lower side of the television screen 1 is assumed to be the on-screen display area 3 for indicating the volume level.

For example, the on-screen display area 3 of the volume on the television screen 1 is Vp from the upper end A of the vertical direction V when the television screen is divided into a vertical direction V and a horizontal direction H.
The point B at this point is set as the vertical area detection point for the on-screen display, and the point D at the left side from C to H1 in the horizontal direction H is set as the horizontal area detection point for the on-screen display.

This setting applies to vertical display counter 4 and horizontal display counter 5.
This is done based on the respective count setting values.

That is, the vertical display counter 4, which is reset to the initial state by the count reset input, is displayed on the television screen 1, for example.
When the horizontal scan from the upper end A starts, the count of horizontal synchronizing pulses is started by the count start input, and when the horizontal scan reaches position B after passing the above Vp, the count value becomes the count setting value and turns on. A horizontal display counter 5 outputs a count output indicating that it is a vertical area detection point B regarding the screen display, and is reset by a count reset input. The count is started by a count start input synchronized with the horizontal synchronization pulse set to the left end C, and the count value becomes the count set value after Hp has elapsed and corresponds to the horizontal area detection point regarding the on-screen display. Output count output.

Then, based on the count outputs of both counters 4 and 5, it is determined that a required circuit (not shown) is the display area 3 for on-screen display data regarding the volume, and the volume data is displayed in a bar shape in the area 3 according to the determination. to be displayed. However, the volume level is indicated by hatching in the bar-shaped display.

By the way, if the horizontal size HS of the circular image 2 in Figure 3 is increased to the horizontal size HS' in Figure 4 due to the need for some kind of adjustment, the circular image will be distorted unless the vertical size VS is adjusted. 2 is distorted into an ellipse as shown by the dotted line, so its vertical size VS' is largely adjusted to match its horizontal size HS' to eliminate this distortion, and as a result, the circular image 2' in Fig. 4 is It is adjusted as follows.

However, when the vertical size is greatly adjusted from vS to vS', the following problems have been pointed out in on-screen display.

In other words, when the horizontal size itself becomes larger, the horizontal area detection point moves to the right of the TV screen 1, so in order to correct this and reach a predetermined detection point, for example, adjust the resistance value of the resistor R. There is no problem because you can change the oscillation frequency of the oscillation circuit 6 to a high value and set the horizontal area detection point to always be D, but if the vertical size becomes large, the area detection point will change like the horizontal size. Since there was no means to always adjust the value to point B, if the vertical size increases as it is, the input cycle of the horizontal synchronizing pulse to the vertical display counter 4 becomes longer, and the count value of the vertical display counter 4 increases. When the set value is reached, the position of Vp is not at point B in Figure 3, but at point B' in Figure 4.
point, that is, a point Vp'(>Vp) from the top of the television screen l.

In this case, the lower part of the bar-shaped display for on-screen display of volume, indicated by the dotted line, protrudes outside the television screen l, which is very inconvenient in terms of on-screen display.

Therefore, it is an object of the present invention to easily adjust the vertical size so that the on-screen display does not protrude outside the television screen.

(Means for Solving the Problems) In order to achieve this object, the on-screen display circuit of the present invention includes an oscillation circuit that outputs an oscillation frequency output for on-screen display, and an oscillation frequency of the oscillation frequency output. A detection circuit that detects whether the value is above a predetermined value, and outputs a switching output of the count setting value when it is detected as being above the predetermined value, and a detection circuit that counts horizontal synchronization pulses and changes the count value to the count setting value. a vertical display counter that outputs a count output indicating that it is a vertical area detection point for on-screen display on a television screen when , a horizontal display counter that counts the oscillation frequency output and outputs a count output indicating a horizontal area detection point for on-screen display on the television screen when the count value reaches a count setting value. It is characterized by the following:

(Function) The oscillation frequency of the oscillation frequency output for on-screen display from the oscillation circuit can be changed in accordance with the horizontal size of the television screen. Then, when this oscillation frequency changes and becomes equal to or higher than a predetermined value, a count setting value switching output is provided from the detection circuit to the vertical display counter.

On the other hand, when the vertical size is adjusted to match the horizontal size, the vertical display counter is switched to a smaller count setting value in response to this switching output input, so even if the vertical size changes, the vertical area is still detected. The dot is adjusted so that it is always in a predetermined position, and as a result, the on-screen display does not extend beyond the television screen.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 is a circuit diagram of an on-screen display circuit according to Embodiment 1 of the present invention, in which parts corresponding to those in FIG. 3 according to the conventional example are given the same reference numerals, and A detailed explanation of the parts will be omitted here.

In this embodiment, it is detected whether the oscillation frequency of the oscillation frequency output of the oscillation circuit 6 is equal to or higher than a predetermined value. When the high level output is
It is equipped with a detection circuit 7 that outputs a switching output of the count setting value of the vertical display counter 4, and the vertical display counter 4 counts horizontal synchronizing pulses as in the conventional case, and when the count value reaches the count setting value. A count output indicating a vertical area detection point regarding the on-screen display on the television screen 1 is outputted at 1, while the count setting value is set to the first one in response to the switching force input from the detection circuit 7. From the count setting value (for example 200) to the second count setting value (for example 180)
).

To explain in detail, the vertical size of the circle image 2 shown in FIG. 1 changes from HS to the horizontal size of the circle image 2 shown in FIG.
In line with the increase in horizontal size HS' such as When the circle image 2 shown in FIG. The timing when the count setting value of 1 is reached is point B' in Figure 4, and the lower part of the on-screen display area 3 is missing as shown in the figure, but in this example, the horizontal size is large. Accordingly, the oscillation frequency of the oscillation circuit 6 is adjusted to be higher by adjusting the resistance value of the resistor R, and as a result, the detection circuit 7 gives the vertical display counter 4 a high level detection output from a low level detection output. Become.

When the vertical display counter 4 receives the /% low level detection output from the detection circuit 7, its count setting value becomes the second count setting value, so it performs a predetermined timing at a faster timing than the first count setting value. A count output will be output. As a result, the vertical area detection point is always at point B instead of point B', and the on-screen display can always be at a predetermined display position even if the vertical size becomes large as shown in FIG.

(Effects of the Invention) As explained above, according to the present invention, when both the horizontal and vertical sizes of the television screen are adjusted, the oscillation frequency of the oscillation frequency output for on-screen display from the oscillation circuit is the same as that of the television screen. On the other hand, when this oscillation frequency changes and exceeds a predetermined value, the detection circuit provides a switching output of the count setting value to the vertical display counter. Since the count setting value can be changed to a smaller value in response to the input of the switching output, the vertical area detection point can be adjusted so that it is always at the predetermined position even if the vertical size changes, and as a result, the on-screen display When adjusting the vertical size so that the on-screen display does not protrude outside the television screen, it is possible to easily adjust the on-screen display so that it does not protrude outside the television screen.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an on-screen display circuit and a television screen according to an embodiment of the present invention, and FIG. 2 shows a circular image and a bar-shaped display with enlarged horizontal and vertical sizes. FIG. 3 is a diagram showing a television screen. The middle figure is a diagram showing a conventional on-screen display circuit and a television screen, and the fourth figure shows a circular image with enlarged horizontal and vertical sizes, with the lower part missing. FIG. 3 is a diagram showing a television screen on which a bar-shaped display is displayed. l... TV screen, 2... Circle image, 3... On-screen display area, 4... Vertical display counter, 5...
- Horizontal display counter, 6... oscillation circuit, 7... detection circuit.

Claims (1)

[Claims] (1) An oscillation circuit that outputs an oscillation frequency output for on-screen display, and an oscillation circuit that detects whether the oscillation frequency of the oscillation frequency output is greater than or equal to a predetermined value, and when it is detected that it is greater than or equal to the predetermined value, sets a count. a detection circuit that outputs a switching output of a value, and a count that counts horizontal sync pulses and that when the count value reaches a count set value, it is a vertical area detection point for on-screen display on the television screen; a vertical display counter that outputs an output and whose count setting value is switched to a smaller value in response to the input of the switching force; 1. An on-screen display circuit in a color television receiver, comprising: a horizontal display counter that outputs a count output indicating a horizontal area detection point regarding the on-screen display on the screen.