JPH0115261Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is directed to a display device using a color matrix panel consisting of liquid crystal (LCD) elements, light emitting diode (LED) elements, etc.

(b) Conventional technology Recently, the development of LCD televisions using color LCD matrix panels (hereinafter simply referred to as color LCD panels) has been actively carried out.For example, the magazine "Nikkei Electronics No. 351" 59
An example of this is introduced on pages 211 to 240 of the publication (September 10, 2016).

The matrix panel display device used in such liquid crystal televisions is generally constructed as shown in Figure 6, in which three primary color display elements R, G, and B are repeated in the horizontal (row) and vertical (column) directions. A color LCD panel is arranged; 2 is a row driver circuit consisting of a shift register that sequentially selects each row of the panel; 3 is a row driver circuit that applies three primary color signals corresponding to each display element in the selected row; This column driver circuit is composed of a shift register 4 and a sample hold circuit 5. Also, 6 is a start pulse supplied to each driver circuit 2 and 4 above with reference to each horizontal and vertical synchronizing pulse HS and VS.
ST ₁ , ST _{2 and} a timing pulse generation circuit that generates the drive clock CP in the row direction; 7 is a color that sequentially derives the three primary color signals R, G, and B input in parallel one by one using the pulses HS and CP; This is a signal switching circuit.

Generally, the three primary color display elements R, G, and B of the color LCD panel 1 are composed of a combination pair of a monochrome liquid crystal element and a color filter disposed in front of the monochrome liquid crystal element.

The color signal switching circuit 7 is connected to each one of the LCD panels 1.
The three primary color signals R,
G and B are derived serially, but if the arrangement order of the display elements changes row by row as shown in the figure, the order in which the three primary color signals from the switching circuit 7 are derived also changes accordingly. It is necessary to switch each line. Therefore, when using the LCD panel 1 arranged as shown in the figure, the color signal switching circuit 7 has conventionally been replaced with two ternary (three-stage) ring counters 8 and 9 as shown in FIG. It consisted of a large number of analog switches S ₁ to S ₁₂ that were opened and closed in response to the output of each stage.

(c) Problems to be solved by the invention However, the conventional circuit described above requires a large number of analog switches, which leads to increased costs and hinders miniaturization and lower power consumption of the device. . Therefore, an object of the present invention is to provide a color signal switching circuit for a color matrix panel display device that eliminates the above-mentioned drawbacks.

(d) Means for Solving the Problems The present invention includes a presettable ternary first counter that counts the drive clock in the row direction of the color matrix panel, and a first counter that counts the horizontal synchronizing pulses and calculates the count value as described above. A color signal switching circuit is constituted by a second counter which presets the first counter and a switch means which serially derives the three primary color signals input in parallel in accordance with the output of the first counter.

(E) Effect According to the above structure of the present invention, the first counter is
Its initial value is set every horizontal period, i.e. 1 of the matrix.
Since the count value changes from the initial value as the driving clock arrives, the order in which the three primary color signals are derived from the switch means is determined by the output of the first counter, and is changed for each row. Switch over.

(F) Embodiment FIG. 1 shows an embodiment of the color signal switching circuit 7 according to the present invention, and numeral 11 counts and inputs the row direction driving clock CP output from the timing pulse generating circuit 6 of FIG. and horizontal sync pulse HS
The first counter is a ternary (three-stage) ring counter that can be preset and has a preset input of . 12R, 12G, and 12B are analog switches that are opened and closed by the outputs Qa ₁ to _{Qa 3} of each stage of this counter, and three primary color signals R, G, and B representing a color image are input to each analog switch, respectively. . Further, reference numeral 13 denotes a second counter consisting of a three-stage ring counter for counting the horizontal synchronizing pulse HS, and the output of each stage is applied as a preset input to the first counter 11. At that time, the first stage, middle stage of the second counter 13,
The outputs Qb ₁ , Qb ₂ , and Qb ₃ of the final stage are connected in this order to input terminals of the upper digit, middle digit, and lower digit of the first counter 11.

Here, for example, if the effective video section in one horizontal period in the case of a television signal is 50 μsec, and the number of display elements for one row of LCD panel 1 (Fig. 6) is 240, then the clock CP ₁ is horizontally synchronized. pulse HS
It is a 4.8MHz pulse synchronized with the first
As the start (count enable) signal given to the second counters 11 and 13, the start pulse (corresponding to the start of the video signal section within one vertical period) created by the timing pulse creation circuit 6 in FIG. 6 is used. Ru.

Therefore, after the first and second counters 11 and 13 are enabled by the start pulse ST ₁ , until the three horizontal synchronizing pulses HS arrive, that is, the first to third rows of the LCD panel 1. For the case where the eyes are driven, the counters 11 and 13
The state of the output of each stage is shown in Fig. 2. In the figure, the "initial value" of the first counter 11 is the state of the output of each stage immediately after the output of the second counter 13 is preset, and "clock No. 1" is the initial value. Clock CP from state
It represents the output state when one arrives,
The same applies to others.

Therefore, as can be seen from FIG. 2 and FIG. 3 showing the operating waveforms in this case, when the first row of the LCD panel 1 is driven, the three primary color signals R, G, B, R, G, B, ... are derived in this order, and when driving the second row, B, R, G, B,
In the order of R, G, ..., and in the third line, G, B, R,
G, B, R, ... are respectively derived in the order, and below,
It will be repeated in the same way. Therefore, the above panel 1
This corresponds to the arrangement order of the display elements above.

The three primary color signals thus sequentially led out to the output line 14 are sampled by the sample and hold circuit 5 shown in FIG. 6 and applied to the electrode leads of each column of the LCD panel 1. At that time, the sample hold circuit 5 controls the clock CP.
Sampling operation is performed at the falling timing of sampling pulses Q ₁ , Q ₂ , Q _{3 .} . . (see FIG. 5) outputted from the shift register 4 in synchronization with . Therefore, the first counter 11 in FIG.
As shown in the figure, a clock obtained by slightly delaying the clock CP using a simple delay circuit consisting of two inverters 15 and 16 and a CR integration circuit 17 is obtained.
It is desirable to supply CP′. In this way, the phase relationships between the three primary color signals R, G, B output from the color signal switching circuit 7 of FIG. 1 and the sampling pulses Q ₁ , Q ₂ , Q ₃ . . . are as shown in FIG. 5. Therefore, it is convenient to perform sampling when the above-mentioned signals R, G, and B have been switched and become sufficiently stable.

(g) Effects of the invention According to the color signal switching circuit of the invention, the number of required switching means is very small, so it can be realized at a low cost.Moreover, each switching means is not conductive at the same time. Power consumption is extremely low, and it also contributes to miniaturization of display devices.

[Brief explanation of the drawing]

Figures 1 to 5 relate to an embodiment of the present invention; Figure 1 is a circuit block diagram showing the main parts thereof, Figure 2 is a diagram for explaining the operation, and Figure 3 is a diagram showing the operation timing. , FIG. 4 is a diagram showing a circuit used in addition to the circuit of FIG. 1, and FIG. 5 is a diagram showing the phase relationship between the output signal of the circuit of FIG. 1 and the sampling pulse. FIG. 6 is a circuit block diagram showing a schematic configuration of a color matrix panel display device, and FIG. 7 is a circuit block diagram showing a conventional color signal switching circuit used in this device. 11...first counter, 13...second counter, 12R, 12G, 12B...analog switch (switch means).

Claims (1)

[Scope of utility model registration request] Provided in a display device using a color matrix panel in which the arrangement order of three primary color display elements arranged sequentially with the horizontal direction as the row direction is changed for each row, the primary color signals applied to each of the display elements are sequentially switched and derived. a presettable ternary first counter for counting drive clocks in the row direction of the panel; and a second counter for counting horizontal synchronizing pulses and presetting the count value in the first counter. and switching means for serially deriving one of the three primary color signals input in parallel in accordance with the output of the first counter.