JPH0320785A - Color display control device - 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 Field of Industrial Application The present invention relates to a color display control device for a personal computer or the like.

2. Description of the Related Art In recent years, color display control devices such as computers have come to be used, which incorporate a look-up table and a DA converter.

A conventional color display control device will be described below.

FIG. 2 is a diagram showing the structure of a conventional color display control device.
is an n-bit image signal, 2 is a data latch that temporarily stores image signal 1, 3 is n-bit rough data stored in data latch 2 and output, 4 is a decoder that decodes latch data 3 into 2n pieces, 5 is 2n decoded signals decoded by decoder 4, 6 is 2nX3
A lookup table with an m-bit structure, 7 is the R brightness data of zero bits output from the lookup table 6,
8 is the l-bit G luminance data output from the lookup table 6, 9 is the ugly bit B luminance data output from the lookup table 6, and 1o is the heavy bit R that converts the R luminance data into an analog value. DA converter for
11 is a multi-bit G DA converter that converts the G luminance data 8 into an analog value, 12 is an l-bit B DA converter that converts the B luminance data 9 into an analog value, and 13 is an output from the R DA converter 10. 14 is an analog G signal output from the G DA converter 11, and 15 is an analog B signal output from the B DA converter 12.

Regarding the color display control device configured as above,
The operation will be explained below.

First, when an n-bit wide image signal 1 is input, the data is held by the data latch 2 for a portion. The held data is output as latch data 3, and the decoder 4 selects one decode signal from among 2n decode signals.

The decoded signal 6 is input to the address terminal of the lookup table 6. Lookup table 6 is 2nX3
Since the memory has an m-bit configuration, one decode signal selected from among the decode signals 5 included in each of the 2n address signals is 3 at the input address.
One bit of data is read. The 311-bit data is divided into three l-bit digital luminance data, each consisting of R luminance data 7, G luminance data 8, and B luminance data 9. The R color data 7 is input to the R DA converter 1o and converted into an R signal 13. Similarly, G luminance data 8 is G
The B luminance data 9 is input to the B DA converter 12 and becomes the B signal 14.
Convert to 6.

Since there are 3m bits of brightness data output at one time from the lookup table 6, the number of types of colors that can be expressed is 23m.
There are colors. Do not rewrite lookup table 6.
The types of colors that can be displayed are 2n. Tsuori 2
This makes it possible to display 2n colors out of 3m colors.

For example, when m=e, n=8, 218=262,144
It is possible to display 28=256 colors. 3 by having lookup table 6! n less than II bits
3m bits of expressible color can be created using bits of image data.

Problems to be Solved by the Invention However, in the conventional structure described above, when changing the brightness of the entire display screen, all data in the lookup table 6 must be rewritten, but rewriting takes time. The problem was that it was not possible.

The present invention solves the above-mentioned conventional problems, and aims to provide a color display control device that can easily and quickly change brightness.

Means for Solving the Problems To achieve this object, the color display control device of the present invention has a configuration in which the brightness can be controlled by including a control device that can control digital brightness data bit by bit after the lookup table. This is what we are trying to solve.

By combining this function with the function, the brightness can be changed instantaneously, and the digital brightness data output from the look-up table can be converted into digital brightness data with different gradations.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration diagram of a color display control device according to an embodiment of the present invention. In FIG. 1, 16 is an R brightness attenuation switch that can switch between fixing the lower 1 bit of the R brightness data 7 output from the lookup table 6 to O or using the brightness data from the lookup table. The brightness attenuation external control signal for R that controls
9, 17 is a G brightness attenuation switch that can switch between fixing the lower 1 bit of G brightness data 8 to 0 or using look-ahead table brightness data. The control signal 20.18 is a brightness attenuation switch for B that can switch between fixing the lower 1 bit of B brightness data 9 to O or using the brightness data of the look add table, and an external brightness attenuation control for B that controls this. Signals 21 and 22 are R luminance signals, 23 is a G luminance signal, and 24 is a B luminance signal.

Note that 1 is an image signal, 2 is a data latch, 3 is latch data, 4 is a decoder, 6 is a decode signal, and 10 is a D for R.
A converter, 11 is D person converter for G, 1 2id
In the B/D converter, 13 is an analog R signal, 14 is an analog G signal, and 15 is an analog B signal, which are the same as those in the conventional example.

The operation of the color composition apparatus of this embodiment configured as described above will be explained below.

First, when the R brightness attenuation external control signal 19 provided externally becomes active, the lower 1 bit of the 7 R brightness data m bits output from the lookup table is sent to the 16 R brightness attenuation switch. Then, switch to 0 from the lookup table data.

For example, assuming that the bit width m of the R color data of 7 is 3, as shown in Figure 3, 1 is the same as O, 3 is the same as 2, 6 is the same as 4, and 7 is the same as 6. Tonashi, 22 R
can reduce the level of the luminance signal for R of 10
After passing through the DA converter, it is possible to reduce the brightness of R color in the analog R signal 13.

Although the explanation has been made for the R color, the same operation is performed for G and B as well.

As described above, according to this embodiment, the brightness can be adjusted by using a switch that sets the lower 1 bit of each m-bit data of R, G, and B to O from the data in the lookup table, and by making this switch controllable from the outside. can be instantly removed,
Further, in this embodiment, the number of bits is 1 bit, but by increasing the number of bits, mosaic-like graphic art can be expressed when displayed on an analog RGB monitor.

In this embodiment, the attenuation of brightness has been described, but it goes without saying that it is also possible to increase the brightness.

Further, the control signal may be placed in each pit of the digital color data in the lookup table, or the control signal may be placed in one pit at a time in the digital color data of the lookup table.
You can make it into a book, and you can set it as you like.

A register may be used to control the control signal, and the control may be controlled by a microprocessor.

Effects of the Invention The present invention provides an excellent color display control device that has the effect of instantaneously changing the brightness by providing a control device that can control digital brightness data from a look-up table in bit units. This is something that can be achieved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a color display control device according to an embodiment of the present invention, Fig. 2 is a block diagram of a conventional color display control device, and Fig. 3 is a block diagram of a conventional color display control device. Image signal input terminal, 2...Data latch, 3...
... Latch data, 4 ... Decoder, 6.
...Decoded signal, 6...Lookup table, 7...R luminance data, 8...
・G brightness data, 9...B brightness data, 10・
...DA converter for R, 11...DA converter for G, 12...I) converter, 13...Analog signal,' 1 4・
... Analog G signal, 16 ... Analog B signal, 19 ... R brightness attenuation switch, 17
・・・・・・Brightness attenuation switch for G, 1B・・・・・・
Brightness attenuation switch for B, 19... Brightness attenuation external control signal for R, 2o... Brightness attenuation external control signal for G, 21.4-Brightness attenuation external control signal for B, 22・・・
. . . R luminance signal, 23 . . . G luminance signal, 24 . . . B luminance signal.

Claims (1)

[Claims] A storage device that stores digital brightness data of red (R), green (G), and blue (B), a control device that can control the digital brightness data from the storage device in bit units, and the control device A color display control device comprising a DA converter for converting controlled digital luminance data into a signal level displayable on an analog RGB monitor.