JPH0243073U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 is a block diagram of a display device using a raster scan method showing an embodiment of this invention, Fig. 2 is a block diagram of a luminance brightness inversion control circuit showing an embodiment of this invention, and Fig. 3 is a block diagram of a conventional display device. FIG. 1 is a configuration diagram of a display device using a raster scan method. In the figure, 1 is an interface section, 2 is a synchronous clock generating section, 3 is a symbol generating section, 4 is a combining section, 5 is a display section, and 6 is a brightness/dark inversion control circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An interface unit generates a video signal, a vertical synchronization signal, and a horizontal synchronization signal by synchronously separating a composite video signal applied from the outside, and a synchronization clock signal is generated by the horizontal synchronization signal generated by the interface unit. a synchronous clock generating section that generates a synchronous clock signal; a symbol generating section that generates a video signal of a symbol such as a character or figure based on the synchronous clock signal generated by the synchronous clock generating section; and a symbol generating section that generates a symbol generated by the symbol generating section. a synthesizing section that synthesizes the video signal, the video signal, the vertical synchronizing signal, and the horizontal synchronizing signal synchronously separated by the interface section to generate a display signal, and the display signal synthesized by the synthesizing section, In a display device using a raster scan method that is composed of a display section that displays an image and a symbol, that is, a display device using a raster scan method that displays symbols such as characters and figures superimposed on an externally input image. In order to automatically invert the brightness of the symbol according to the brightness of the entire image area of the display section, an average brightness level detection circuit that detects the average brightness level of the video signal in the entire image area, and an average brightness level detection circuit that detects the average brightness level of the video signal in the entire image area, A reference signal source that sets the contrast inversion level to a predetermined value in advance, and the average brightness level of the video signal in the entire image area detected by the average brightness level detection circuit and the brightness of the symbol set by the reference signal source. A comparison circuit that compares the inversion levels and generates an output signal according to the magnitude thereof, a brightness brightness inversion circuit that inverts the brightness of the symbol, and a brightness brightness inversion circuit that inverts the brightness of the symbol using the video signal of the symbol and the brightness brightness inversion circuit described above. 1. A display device using a raster scan system, characterized in that a brightness brightness inversion control circuit comprising a switching circuit for switching between a video signal of a symbol and a video signal of a symbol according to an output signal of the comparison circuit is added.