Video signal producing apparatus and video signal producing method

• US 6,628,324 B1
• Filed: 04/11/2000
• Issued: 09/30/2003
• Est. Priority Date: 09/30/1999
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Mitsubishi Electric Semiconductor Application Engineering Corp.
• Inventors: Onishi, Yasushi, Hosotani, Osamu
• Primary Examiner(s): LEE, MICHAEL
• Application Number:
  US09/546,522
• Time in Patent Office: 1,267 Days
• Field of Search: H04/N 1.700, H04/N 1.702, 348/179, 348/181, 348/182, 348/183, 348/188, 348/569, 348/570, 348/563, 348/173, 348/177, 348/178, 348/180, 348/189, 348/190
• US Class Current: 348/177
• CPC Class Codes: H04N 17/045 Self-contained testing apparatus
• CPC Class Codes: H04N 5/445 for displaying additional information H04N5/50 takes precedence

Abstract

When a manufacturer or a user desires to adjust a Braun tube, it is required to display a test pattern satisfying setting conditions of display modes on the Braun tube. To set the display modes of the test pattern, a plurality of horizontal synchronizing signals and a vertical synchronizing signal are generated by a timer circuit for each field. Also, display modes (for example, shape, position, size, color and luminance) of a type of characters having the same shape are set in an OSD circuit to set the display modes of the test pattern composed of the characters having the same shape. Thereafter, a composite video signal of the test pattern satisfying the display modes is produced on the basis of the horizontal synchronizing signals and the vertical synchronizing signal in the OSD circuit, and the test pattern is displayed on the Braun tube according to the composite video signal. Accordingly, because the composite video signal of the test pattern satisfying the display modes can be produced without using any private circuit, the video signal producing apparatus can be produced in a small size and at a low cost.

Claims

1. A video signal producing apparatus, comprising:

synchronizing signal generating means for generating a plurality of horizontal synchronizing signals and a vertical synchronizing signal complying with a prescribed video signal broadcasting standard;

setting means for setting a display mode of two or more characters to set the display mode of a test pattern composed of the characters; and

video signal producing means for producing a composite video signal of the test pattern satisfying the display mode set by the setting means according to the horizontal synchronizing signals and the vertical synchronizing signal generated by the synchronizing signal generating means.

2. A video signal producing apparatus according to claim 1, wherein the display mode of the characters set by the setting means is a display shape of the characters, a display position of each character, a display size of the characters, a display color of each character or the luminance of each character.

3. A video signal producing apparatus according to claim 1, wherein the luminance of the characters is set to a particular luminance degree by the setting means as a setting condition of the display mode of the characters, and the video signal producing means comprises

an output circuit for selecting a particular electric potential value corresponding to the particular luminance degree of the characters from three or more electric potential values including an electric potential value corresponding to black and an electric potential value corresponding to white and setting the electric potential of a pattern signal corresponding to the characters in the composite video signal to the particular electric potential value.

4. A video signal producing apparatus according to claim 1, further comprising:

renewing means for controlling the synchronizing signal generating means to generate a plurality of horizontal synchronizing signals and a vertical synchronizing signal complying with a new video signal broadcasting standard in place of the horizontal synchronizing signals and the vertical synchronizing signal complying with the prescribed video signal broadcasting standard.

5. A video signal producing apparatus according to claim 1, further comprising:

changing means for controlling the setting means to set the display mode of the characters to a new setting condition in place of a predetermined setting condition of the display mode.

6. A video signal producing apparatus according to claim 1, wherein the test pattern is obtained by combining the characters having the same shape set by the setting means.