JPS5859691A - Color television device using color liquid crystal display element - Google Patents

Abstract

PURPOSE:To give linearity to luminance, by using a color liquid crystal display element instead of the conventional color cathode-ray tube to display a color picture and performing the reverse gamma correction to correct again the gamma correction which is performed when the color cathode-ray tube is used. CONSTITUTION:The color video signal transmitted from a broadcasting station is applied to mixing circuits 14-16 as primary color signals where a luminance signal EY is subtracted. The luminance signal EY is inputted to a reverse gamma correcting circuit 13, and the part, which is subjected to the gamma correction processing, included in the transmitted signal is corrected again and is restored to the original state to output a signal EY', and this signal is inputted to mixing circuits 14-16. Primary color signals ER', EB', and EG' are outputted from mixing circuits 14-16. These primary color signals are applied to an input transforming circuit 17 and have levels and amplitudes adjusted and are converted to serial signals alternately in order by a signal switching circuit 18. Primary color signals outputted from the signal converting circuit 18 are digitized in an AD converter 21 and are stored in a shift register 22. Stored primary color signals are inputted to a color liquid crystal display element LCD through a Y driver 24.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color television device using a color liquid crystal display element.

In recent years, various attempts have been made to develop picture tubes to replace color cathode ray tubes, and one of them has been proposed to utilize a color liquid crystal display element made of gold.6 The present invention is based on the present invention.

A television device that can display color images using such a color liquid crystal display element! 1 has been improved in order to obtain linearity of its brightness. In other words, the brightness-grid ζ-pressure characteristic of a conventional color cathode ray tube draws a curve as shown in Figure 1, so this is completely canceled out. Then, the optical signal is output after performing the required gamma correction so that it becomes a straight line when combined. The second figure shows the relative human car relative output characteristic curve W4 of the gamma correction circuit, which draws a curve opposite to the luminance-glue voltage characteristic curve shown in the first factor.

An embodiment of the present invention will be described below based on the drawings. FIG. 5 shows the cross-sectional structure of a color liquid crystal display element that displays a color image.
(1) front glass substrate, (2) rear glass substrate, R
,G,B,R,o,13. -...- are formed on the inner surface of the front glass substrate (1), and (3) LD, a transparent insulating film made of acrylic resin, etc. are formed on the inner surface of the front glass substrate (1).
XI Ke, polarized confectionery R1G%B on the insulating film (3)...
The scan applied in the direction of extension of ... and the direction of the i hundred angle is
Ym, n are signal W poles formed on the inner surface of the rear glass substrate (2) facing the polarizing elements R, G, B--. A (4) and (5) are scan electrodes XI, which are formed of a transparent conductive film such as scan t&Xl, signal W pole signal, nii, tin oxide SnO2, indium oxide Xn20s, etc.
, and the signal electrodes 'frn, n, and can be formed by applying an organic resin such as polyimide with a spinner. These orientations h(4) (5)
are subjected to rubbing treatment in directions 90'' different from each other to impart alignment characteristics that orient liquid crystal molecules in a certain direction.

(6) 11. The alignment film (41(61) is a nematic liquid crystal with positive anti-electrical anisotropy filled between
5) The molecular structure that has been rotated by 90@mξ due to the regulating force, that is, Lyste.

It is said to be Donematifuku e1 formation. (7) Rear glass substrate (2) The color polarizing element R disposed outside
, G, B, . . . , a polarizing plate with a polarization plane perpendicular to (
8) is a white light source. In the figure, the electric field applied area is shown as ON, and the non-applied area is shown as OFF. In the ON area, the light emitted from the white light source (8) passes through the polarizing plate (7). through fl
i[becomes linearly polarized light and passes through the liquid crystal (6) as Il! The light then enters the color polarizing elements R, G, B, . . . . However, the polarization plane of these color polarizing elements R, G%B...
Since it is perpendicular to the polarization plane of the linearly polarized light coming from the rainbow, the colors of the red, green, blue, etc. lights at the colored end of each element are combined using the primary colors on the outgoing side, and any desired color is created. Mixed colors are displayed. On the other hand, in the OFF region, the linearly polarized light transmitted through the polarizing plate (7) is
Liquid crystal (6) VC rotated 90” and color polarizing element R
, G%B... Reach 7. In this case, the polarization plane of the rotated linearly polarized light and the polarization plane of the color polarizing elements R, G%B, etc. match, so the linearly polarized light is transmitted,
Appears as a white background on the display side.

FIG. 4 shows the specific configuration of the scanning electrode x1 and the signal electrodes Ym, n, and a four-rate signal is transmitted onto one scanning electrode Xi in a quadruple layer in which poles Yxx% Y1g, Y13, and Y14 face each other. It is a "III-polar structure" called a matrix.

Portions a1, az, and az indicated by diagonal lines in the figure correspond to color polarizing elements R, G, and BK, respectively, and these six portions constitute one set of display pixels. In order to reproduce the existing color television image, it is necessary to use 1m60,
If the signal type 1igYm, n4C is set to m-160, n-4, it is quite possible.

FIG. 5 shows color liquid crystal display elements I and C having the above-mentioned configuration.
The circuit system for driving D.1 is shown, (9) (2) Qll is,
Each primary color signal from the cuff-video signal transmitted from the broadcasting station:
：Divide the luminance signal E! The terminal az is a terminal to which the red difference No. 1d git, the blue difference signal gn, and the green difference signal go from which the subtracted red difference signal gn and the green difference signal go are input, and az is a terminal to which the luminance signal gy described above is input. The inverter is an inverse gamma correction circuit that inputs the luminance signal needle, and functions to re-correct the part of the transmitted signal 1 that has been subjected to gamma correction processing and return it to its original state.

<141 (15IQ. is each color difference signal ER, ga, ta
is one input, and the corrected output E! from the inverse gamma correction circuit I is taken as one input. R mixed circuit, B mixed circuit, Q where ′ is the other human power
In the mixing circuit, each color difference signal ER, gn, go and the modified luminance signal E'! ' are mixed to produce primary color signals g rtt, Eml, g
Output el. (1?) are these primary color signals g
R', WB'JG' level and amplitude
input transformation circuit, the a-th input is the primary color signal Wx',
A signal switching circuit that converts g ml, EG' into a serial signal that outputs 42 signals alternately in order, a minus, 15Kf (by manually inputting a horizontal synchronizing signal with a frequency of Z, 2.4M) with a frequency of iZ ( The oscillator that outputs the d signal counts i, that is, 262.5 times, of the horizontal synchronizing signal 525H necessary for displaying the m-image using a counter that counts the 0 output of this oscillator.

This is done by inputting the vertical synchronizing signal V, which is output every 262.5M period, as a reset signal. υ is an A/i) converter that performs physcial conversion of the primary color signals sequentially output from the signal switching circuit;
2) is a shift register that stores A/D converted primary color signals, and these signal switching circuits [1, A/D converter αυ and shift register (2) are driven by the output of the oscillator as]. .

(to) is a latch circuit to which the contents of the shift register @ are transferred, and is controlled by a clock signal outputted from the counter (2) every 8H period, and its contents are changed. ■ is,
Based on the contents of the latch circuit, the driver that supplies the video signal to the cuff liquid crystal display element LCD receives the signal output from the counter every 262.5M period. A shift register is operated manually as a data signal, and a shift operation is performed using a clock signal outputted from the counter 2 every 8H period. (to) is a driver that moves the scanning electrode x1 of the color liquid crystal display element LCD based on the contents of the shift register. Of the 262.5 H of horizontal synchronization 4i4, the signal actually involved in image compensation is about 240H, so if 8H and 2 scans are made, 30 scanning electrodes will be sufficient.In this example 1
:, F+ means horizontal synchronization signal 1H19H, 17H...
The display is performed using the video signals extracted every 8H, as shown in . In addition, if the number of scanning electrodes is increased, image followability can be improved, but a more precise pattern is required due to the electrode structure of the cuff-liquid crystal display element. ``Let me explain one thing.

This correction circuit 0 calculates the characteristics of the light output (brightness #i) B m' with respect to the input (grid voltage) Bm in the cathode ray tube. and output E! It is given between '. That is, the input Ex and output E of the correction circuit t13
Between Y′, i xt = K E Y2.2 °−°−°
To °121: A constant holds true. A specific example will be explained based on FIG. 6. Dl is a silicon diode, Dl is a germanium diode, and the respective forward drop voltages are Va and VB (
T expressed as VG<VB).

R3 is a resistor K connected in series with the silicon diode D1.
sR2 is a resistor connected in series to the germanium diode D2, and each series circuit is connected in parallel with the resistor R1. The input side of this parallel circuit T, that is, the anode terminals of the diodes D1 and Dl are connected to the input terminal Q3, and the luminance signal E! is input, and the output side, that is, the diode L)t
, Dl are connected to the e input terminal of the comparator υ. Comparator V! It is grounded via the ΦΔ input terminal resistor R4 of η. RO is a resistance interposed between the e input terminal and the output terminal of the comparator (B), and (to) is the output E Y
' is the output terminal from which it is taken out. In the circuit diagram having such a configuration, the following three cases can be considered depending on the value of the human power signal lx. Note that the amplitude of input EY is 0 to 1v.
shall be.

1) jNY < VG < VB (if D, m x'
= -T-RY 1) If Ve < Ey < Vg tD, Yl=
If EY 1Rz 1) Vo < va ≦-Rx, then Y, (
RIR2+1 (2R1R11R1) Ro EY-1--
'R*Pressure 25 ---- In the above three cases, by appropriately setting the value of the resistance RoR1R2Rs, a curve that approximately satisfies Equation 21 can be obtained. This is shown as a solid line in Figure 7. If we now set vQ==α25V%V8=0.7y,
The value of each resistor is chosen to be Ro=5, Ω, f(t=).

The color television device of the present invention as described above uses a color liquid crystal display element in place of the existing color cathode ray tube, and is capable of displaying color images and supplementing the unique characteristics of the tube. By providing an inverse gamma correction circuit that further corrects the gamma correction that has been made,
It becomes possible to provide linearity to the brightness of the image, and it is possible to obtain an image with stable brightness.

[Brief explanation of the drawing]

! Figure 141 is a curve diagram showing the brightness-grid voltage characteristics of a cathode ray tube. Figure 2 is a curve diagram showing relative human power-relative output characteristics. Figure 3 is a cross-sectional view of the cuff-liquid crystal display element.
The figure is an electrode pattern diagram of the same element, Figure 5 is a circuit block diagram of an embodiment of the present invention, Figure 6 is a circuit diagram specifically showing an inverse gamma correction circuit, and Figure 17 is a curve showing luminance input-luminance output characteristics. It is a diagram. L CD-...color liquid crystal display element, side...reverse gamma correction circuit, α-hiro...R mixing circuit, μS...B mixing circuit, Kan...G mixing circuit, Q7)...manpower metamorphic circuit,
a signal conversion circuit, a hot water... oscillator, circle... counter, t2υ... A/D converter, low... shift register, (to)... Foote circuit, U Buddha... ·driver. Procedural amendment (spontaneous) March 3, 1986 Commissioner of the Japan Patent Office 1 Indication of the case Patent Application No. 157751 of 1982 2 Name of the invention Cuff-TV device using color liquid crystal display element 6 Patent applicant address: 2-18 Keihan Hondori, Moriguchi City Name (188) Sanyo Electric Co., Ltd. Representative: Kaoru Iue 4 Agent address: 2-18 Keihan Hondori, Moriguchi City Contact information: Telephone (Tokyo ) 835-1111 Patent Center Resident Kamata 6, Detailed description of the invention column of the specification subject to amendment Attached drawing 6, 1 volume of amendment 0 Amended the statement 1IR2 on page 9, line 6 in the specification to IR2 do. 0 In the specification, si@7th line lR2R5 is corrected to t RIR2R11. Correct it to ``Mei Mkai@9Th line 14 r8.99'' to rg, 9 to Ω''. @In attached drawing! Correct Figure 5 as shown in the attached sheet.

Claims (1)

[Claims] 1. A color television device that receives a gamma-corrected color image signal transmitted from a broadcasting station and displays it in color on a color liquid crystal display element, comprising means for inversely gamma-correcting the received color image signal. A color television device using a color liquid crystal display element characterized by a tube arrangement and linearity in brightness characteristics.