JPS61255386A - Display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] (11 The present invention relates to ORT (0 methods Ray T
ube) VB based on separate signal and dot clock
P.

The present invention relates to a display device that detects HBP.

[Prior art]

(2) In general, VBP and HBP naturally differ depending on the personal computer or other equipment, but they may also change depending on the software even in the same personal computer or equipment. If the VBP and HBP change, the screen position will shift, but this is not a big concern when using a CRT. However, frame memory etc. are VSa.

When driving based on HBC, dot clock, nVB
The changes in P and HBP are profound.

〔the purpose〕

(8) The present invention is a precautionary measure to deal with changes in VBP and HBP caused by equipment, software, etc. as described above, and automatically detects VBP and HBP to ensure that frame memory etc. are always in normal condition. The purpose is to make it work.

〔overview〕

(4) VBP detection according to the present invention is performed by VSC output from a personal computer or other equipment.

1180, is characterized by requiring only a video signal,
This is performed based on the video signal that appears first after VSC. H
BP detection is characterized in that only VSO, H2C, dot clock, and video signals are required, and VC is performed based on the video signal that appears first after HSC.

〔Example〕

(5) Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment.

FIG. 1 shows a (b) schematic diagram of an embodiment of a VBP detection circuit configured according to the present invention. Moreover, the timing chart is shown in FIG.

In Figure 1, the first stage Flip-Flop (hereinafter F
, F) are set at the rising edge of VSC and reset when the video signal appears. The second stage counter is H2O from the time F, 11' of the first stage is set.
The count starts completely and stops when it is reset. The value of the counter at this time is the number of rasters during which the first video signal appears from VSC. This value is V
By latching SC with an appropriately delayed VSCDELAY signal, VBP can be controlled. VSC
D] T! The counter is also reset at the same time by the LAY signal, and the same operation is repeated again when the next VSC comes. Next, FIG. 5 shows a circuit diagram of an embodiment of an HBP detection circuit constructed using an unconventional method. Further, the timing chart is shown in FIG. In Figure 5, F and F in the first row are H
It is set at the rising edge of 2C and reset when the video signal appears. The counter counts the number of dot clocks during this period and stops.

H80 DELAY which delayed H2C appropriately
By latching with one signal, it is possible to obtain the number of dot clocks in the video signal cylinder that appears first in the rask. This operation is returned for one frame 〈υ, and the smallest value among them is adopted as '1HBP.

〔effect〕

L6) As is clear from the above embodiments, according to the present invention, VBP and HBP can be automatically detected. Therefore, the VB of the television separate signal
Even when P and HBP change, the setting of the frame memory drive standard can be automated.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a VBP detection circuit to which the present invention is applied, and FIG. 2 is a timing chart thereof. FIG. 3 shows an embodiment of the HBP detection circuit to which the present invention is applied, and FIG. 4 is its timing chart. that's all

Claims (1)

[Claims] Using only the vertical synchronization signal (hereinafter referred to as VSC), horizontal synchronization signal (hereinafter referred to as HSC), and video signals output from a personal computer or other equipment, the vertical back porch is created based on the first video signal that appears after VSC. (Hereafter VB
Using only the vertical back porch automatic detection circuit that detects the vertical back porch (abbreviated as P), VSC, HSC, video signal, and dot clock, detects the horizontal back porch (hereinafter abbreviated as HBP) based on the video signal that appears first after HSC. A display device comprising: a horizontal back porch detection automatic detection circuit.