Method for controlling video signal circuit, display device and computer

• US 20040196271A1
• Filed: 09/17/2003
• Published: 10/07/2004
• Est. Priority Date: 03/19/2001
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Kaneyasu, Isamu
• Application Number:
  US10/663,644
• Publication Number:
  US 20040196271A1
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 1/16 the pattern of rectangular co-ordinates extending over the whole area of the screen, i.e. television type raster
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/10 Special adaptations of display systems for operation with variable images
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4318 by altering the content in the rendering process, e.g. blanking, blurring or masking an image region image enhancement or restoration in general G06T5/00
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/8153 comprising still images, e.g. texture, background image
• CPC Class Codes: H04N 5/148 Video amplifiers amplifiers in general H03F
• CPC Class Codes: H04N 5/57 Control of contrast or brightness

Abstract

An object is to display both still images and moving images in good condition. A preamplifier circuit (311) for amplifying a supplied video signal S1 and adding a bias voltage Vba to the same, an output circuit (312) for amplifying power of the signal supplied from the preamplifier circuit (311) and inverting the same, and a variable bias circuit (314) for changing a level of the bias voltage Vba added in the preamplifier circuit (311) are provided. The preamplifier circuit (311) changes its gain Ga in accordance with the change of the bias voltage Vba by the variable bias circuit (314).

Claims

1. A method for controlling a video signal circuit including a preamplifier circuit for amplifying a video signal and adding a bias voltage to the same and an output circuit for amplifying power of the signal that is delivered from the preamplifier circuit, wherein

a level of the bias voltage that is applied by the preamplifier circuit is changed in accordance with contents of the video signal.

2. The method according to claim 1, wherein the level of the bias voltage is changed in accordance with the video signal that is either a video signal related to a still image or a video signal related to a moving image.

3. A video signal circuit comprising:

a preamplifier circuit for amplifying a supplied video signal and adding a bias voltage to the same;

an output circuit for amplifying power of the signal that is delivered from the preamplifier circuit; and

a variable bias circuit for changing a level of the bias voltage that is added in the preamplifier circuit.

4. The video signal circuit according to claim 3, wherein the output circuit amplifies power of the signal that is delivered from the preamplifier circuit and inverts the same.

5. The video signal circuit according to claim 3, wherein the preamplifier circuit has a variable gain that is changed within the maximum amplitude of the output signal in accordance with the change of the bias voltage by the variable bias circuit.

6. A display device for displaying images on a screen in accordance with a video signal, comprising:

a preamplifier circuit for amplifying a supplied video signal and adding a bias voltage to the same;

an output circuit for amplifying power of the signal that is delivered from the preamplifier circuit; and

a variable bias circuit for changing a level of the bias voltage that is added in the preamplifier circuit in accordance with an adjustment signal.

7. The display device according to claim 6, wherein the variable bias circuit increases the bias voltage if the video signal relates to a still image and decreases the bias voltage if the video signal relates to a moving image.

8. The display device according to claim 6, further comprising a reception circuit for receiving a video type signal for discriminating whether the video signal relates to a still image or to a moving image, wherein

the variable bias circuit uses the video type signal as the adjustment signal for changing the level of the bias voltage.

9. The display device according to claim 6, further comprising an operation portion for adjusting the level of the bias voltage, wherein

the variable bias circuit uses a signal from the operation portion as the adjustment signal for changing the level of the bias voltage.

10. A computer system comprising a computer body and a display device for displaying images on a screen in accordance with a video signal generated in the computer body, comprising:

a video signal circuit including

a preamplifier circuit for amplifying the video signal and adding a bias voltage to the same,

an output circuit for amplifying power of the signal that is delivered from the preamplifier circuit,

a reception circuit for receiving a video type signal related to contents of the video signal, and

a variable bias circuit for changing a level of the bias voltage that is added in the preamplifier circuit in accordance with the video type signal;

a video detection portion for generating the video type signal; and

a transmission portion for transmitting the generated video type signal to the reception circuit.

11. A computer that can display images on a screen of a display device in accordance with a generated video signal, comprising:

a video detection portion for generating a video type signal for discriminating the video signal that is either a video signal related to a still image or a video signal related to a moving image; and

a transmission portion for transmitting the generated video type signal to the display device.

12. The computer according to claim 11, further comprising a table indicating a relationship between a file name of a program for generating a video signal and the video type signal, wherein

the video detection portion refers to the table for generating the video type signal.

13. A computer program that is used for a computer that can display images on a screen of a display device in accordance with a generated video signal, the program makes the computer perform the steps of:

generating a video type signal for discriminating the video signal that is either a video signal related to a still image or a video signal related to a moving image; and

transmitting the generated video type signal to the display device.

14. A recording medium that can be read by a computer and stores the computer program according to claim 13.