CN1301425C

CN1301425C - Single pixel drive circuit for transmission and reflection type LCD

Info

Publication number: CN1301425C
Application number: CNB03119821XA
Authority: CN
Inventors: 林孝义; 温志坚
Original assignee: Toppoly Optoelectronics Corp
Current assignee: TPO Displays Corp
Priority date: 2003-03-04
Filing date: 2003-03-04
Publication date: 2007-02-21
Anticipated expiration: 2023-03-04
Also published as: CN1527261A

Abstract

The present invention relates to a driving circuit of a single pixel of a penetration and reflection type liquid crystal display. Different analog digital signal converters are respectively used for controlling a gamma correcting signal of a penetration type liquid crystal capacitor and a gamma correcting signal of a reflection type liquid crystal capacitor, and the display quality of the penetration and reflection type liquid crystal display can be improved. The present invention comprises a first transistor, a second transistor, a first signal converter and a second signal converter, wherein the gate terminals of the first transistor and the second transistor are commonly coupled to a scan line; the first signal converter is coupled with the source terminal of the first transistor through a first data line; the second signal converter is coupled with the source terminal of the second transistor through a second data line; the drain terminal of the first transistor is coupled to the penetration type liquid crystal capacitor; the drain terminal of the second transistor is coupled to the reflection type liquid crystal capacitor.

Description

The driving circuit of the single pixel of penetrating reflective LCD

Technical field

The present invention relates to a kind of driving circuit of LCD, particularly relate to a kind of driving circuit of penetrating reflective LCD.

Background technology

Gently, thin, short, become the primary consideration of flat-panel screens technology for a short time, and liquid crystal panel has appeared vividly more and has become the main flow of present display.Panel of LCD can be divided into active and passive type, and its reaction velocity of active matrix liquid crystal display, resolution, image quality and dynamic image are all good than passive type, along with the demand of user for high image quality, display panel is transformed into full-color already by monochrome, and pay attention to day by day for the power consumption of LCD, number of color, resolution etc., therefore have to adopt reaction velocity comparatively fast, more to meet the active-matrix panel that dynamic image is used, therefore adopt the active-matrix panel to become present technological trend.

The display technology of present a kind of hot topic is low-temperature polysilicon film transistor panel of LCD (LTPS TFT-LCD), advantages such as its tool high brightness, low power consumption, super-resolution degree, high image quality and reaction velocity are fast are most advanced and the most competitive technology in the TFT-LCD industry.

In order to reduce the consumed power of panel, equal orientating reflex formula of present most technological trend (Reflective Type) or the development of penetrating reflective (Transflective Type) liquid crystal panel.The pattern that penetrates (transmissive mode) of penetration reflecting type liquid crystal display panel and the brightness of all using same character used in proper names and in rendering some foreign names Maqu line to proofread and correct each picture element with reflective-mode (reflectivemode) at present.Yet the penetration liquid crystal has different characteristics with reflection type liquid crystal, therefore the character used in proper names and in rendering some foreign names Maqu line of proofreading and correct is also inequality, use same character used in proper names and in rendering some foreign names Maqu line then can influence its image quality, therefore a kind of real necessity that belongs to of driving circuit of improving the image quality of penetrating reflective LCD.

Summary of the invention

In view of above problem, fundamental purpose of the present invention is to provide a kind of driving method of penetrating reflective LCD, uses the image display quality that improves the penetrating reflective LCD.

Therefore, for achieving the above object, the penetrating reflective LCD that the present invention is disclosed includes a first transistor and a transistor seconds, and its gate terminal coupled in common is to the one scan line; One first signal converter is by the source terminal coupling of one first data line and this first transistor; And one second signal converter, by the source terminal coupling of one second data line and this transistor seconds.

Wherein, this drain electrode end of this first transistor is coupled to this penetration liquid crystal capacitance, and this drain electrode end of this transistor seconds is coupled to this reflection type liquid crystal electric capacity.

For making purpose of the present invention, structure, feature and function thereof there are further understanding, in conjunction with

Embodiment is described in detail as follows.

Description of drawings

Fig. 1 is the driving circuit for the known single pixel of penetration reflective liquid-crystal display; And

Fig. 2 is the driving circuit for the single pixel of penetration reflective liquid-crystal display of the present invention.

The drawing reference numeral explanation

10 ... the scan shift working storage

11 ... sweep trace

20 ... the data shift working storage

21 ... signal converter

22 ... data line

24 ... transistor

25 ... the penetration liquid crystal capacitance

26 ... reflection type liquid crystal electric capacity

27 ... reflection type liquid crystal electric capacity

28 ... the penetration liquid crystal capacitance

31 ... first signal converter

32 ... second signal converter

41 ... first data line

42 ... second data line

51 ... the first transistor

52 ... transistor seconds

61 ... storage capacitors

62 ... storage capacitors

Embodiment

The technology of penetration reflecting type liquid crystal display panel is the utilization that makes full use of environment light source and can reduce backlight, utilization is done the reflecting surface of a small skew as reflecting plate on picture element, the veiling glare of image and surface reflection is separated, and make light source concentrate and being distributed in certain visual angle of control light, and reflex to observer's direction, not only effectively promote the utilization factor of light, the brightness of panel also promotes with contrast thereupon, and the reflecting system that therefore how to improve light utilization efficiency becomes a technical task that needs to be resolved hurrily then.

In the LCD, each picture element all is to adopt the interleaved mode of X, Y-axis to drive, and reach the high data density display effect in the mode of active-matrix (active-matrix addressing) in the at present disclosed technology, it has preferable display effect and resolution, the mode that is adopted is the transistor that utilizes thin film technique to make, and utilizes scanning method to select the Push And Release of any one display dot (pixel).On glassly draw netted tiny conducting wire as transmission line, electrode is arranged the matrix switch that forms by thin film transistor (TFT), then there is a gauge tap in the place of intersecting at each circuit, though driving signal scans and mistake in each display dot apace, but have only on the electrode selecteed display dot in the transistor matrix to obtain being enough to drive the voltage of liquid crystal molecule, the contrast that makes the liquid crystal molecule axle steer form " bright or dark ", not selecteed display dot are exactly the contrast of " dark or bright " naturally.

And the fundamental purpose that the penetrating reflective panel of LCD proposes is to reduce the power attenuation of liquid crystal panel, is to utilize the reflection of extraneous light to reduce the use in backlight source, to reduce the loss of power.Therefore, have a penetrating region (Transparent Area) and echo area (ReflectiveArea) in each picture element, image signal is then controlled by data line in the picture element.

The penetration reflecting type liquid crystal display panel that known technology is disclosed, can be divided into an echo area (Reflective Area) and penetrating region (Transparent Area) according to liquid crystal characteristic, the demonstration of echo area is to be provided by reflection type liquid crystal, and the demonstration of penetration is to be provided by the penetration liquid crystal.The seen image quality of user is the result after proofreading and correct via character used in proper names and in rendering some foreign names Maqu line, and the gamma correction of echo area and penetrating region is to use same character used in proper names and in rendering some foreign names agate calibration curve to adjust brightness.

So-called character used in proper names and in rendering some foreign names Maqu line is meant the respective function curve between its input value and the output valve, and when an ancient woman's ornament agate value was 1, curve was 45 degree straight lines, promptly imports and to export concentration identical.Be lower than 1 an ancient woman's ornament agate value and will cause the output brightening, be higher than 1 an ancient woman's ornament agate value and will cause the output darkening, it is big more that an ancient woman's ornament agate value and 1 differs, and curvature of curve is more little.And because the characteristic of an ancient woman's ornament Maqu line, gama correcting can not influence the concentration territory of image, and just influence the distribution of concentration, that is the brightening of arriving of user's visual experience (when an ancient woman's ornament code value less than 1) or darkening (when an ancient woman's ornament agate value greater than 1) image, gama correcting mainly acts on the middle tone part.When an ancient woman's ornament agate value of using greater than 1 the time, highlights can be compressed and dark portion is expanded, when an ancient woman's ornament agate value of using less than 1 the time, highlights is expanded and dark portion is compressed.

Be depicted as the driving circuit of the single picture element of known LCD as " Fig. 1 ", scan shift working storage (Scan Shift Register) 10 is in order to control one scan line 11, which pixel signal is luminous in the decision matrix, data shift working storage (Data Shift Register) 20 is in order to controlling signal converter 21, data line 22 is in order to the switch of oxide-semiconductor control transistors 24, and by transistor 24 driving penetration liquid crystal capacitances 28 and reflection type liquid crystal electric capacity 27, that is make liquid crystal turn to control light to pass through.Penetration liquid crystal capacitance 28 is to be provided by signal converter 21 with the character used in proper names and in rendering some foreign names Maqu line correctiong signal of reflection type liquid crystal electric capacity 27.

When sweep trace 11 scannings are luminous with selected a certain picture element, correctiong signal can pass through a signal converter 21, analog signal is converted to digital signal, import signal in penetrating region electrode and echo area electrode correcting luminance via data line 22 by transistor 24, that is, penetration liquid crystal capacitance 28 in the same picture element is to proofread and correct by same character used in proper names and in rendering some foreign names agate calibration curve with reflection type liquid crystal electric capacity 27, but because the cause of penetration liquid crystal capacitance and reflection type liquid crystal electric capacity self character makes that the result who utilizes same character used in proper names and in rendering some foreign names Maqu line to proofread and correct is not satisfactory.

Therefore, the present invention is directed to above-mentioned problem and propose a solution, shown in " Fig. 2 ", for improving the image quality of penetration liquid crystal capacitance and reflection type liquid crystal electric capacity, the data line of its oxide-semiconductor control transistors switch is controlled with different signal converters.As shown in Figure 2, the driving circuit of single pixel includes one first signal converter, 31, the second signal converters 32, the first transistor 51, transistor seconds 52, and pixel then is made of a penetration liquid crystal capacitance 25 and a reflection type liquid crystal electric capacity 26.

Grid (Gate) coupled in common of the first transistor 51 and transistor seconds 52 is to sweep trace 11, the source electrode of the first transistor 51 (Source) is coupled to first data line 41, drain electrode (Drain) is coupled to penetration liquid crystal capacitance 25, source-coupled to the second data line 42 of transistor seconds 52, drain electrode (Drain) is coupled to reflection type liquid crystal electric capacity 26.

First signal converter 31 is via the switch of first data line 41 with control the first transistor 51, and second signal converter 32 is via the switch of second data line 42 with control transistor seconds 52.When sweep trace 11 is selected this pixel, cooperate the control of first data line 41 and second data line 42, make the first transistor 51 and transistor seconds 52 be opened, and penetration liquid crystal capacitance 25 its correctiong signals are proofreaied and correct its brightness by first signal converter 31 via the first transistor 51.Similarly, the correctiong signal of reflection type liquid crystal electric capacity 26 is proofreaied and correct its brightness by second signal converter 32 via transistor seconds 52.

Wherein, first signal converter 31 and second signal converter 32 are to be an analog digital signal converter.The first transistor 51 is a thin film transistor (TFT) (Thin Film Transistor with transistor seconds 52; TFT) and penetration liquid crystal capacitance 25 also is parallel with a storage capacitors 61, in order to keep the voltage of liquid crystal capacitance 25.Reflection type liquid crystal 26 is parallel with a storage capacitors 62 equally, in order to keep the voltage of liquid crystal capacitance 26.

Use different signal converters to handle for reflection respectively with the character used in proper names and in rendering some foreign names agate calibration curve of penetrating component, can produce influences quality preferably.And, need not need in order to improve renewal frequency (refresh) to sacrifice the time of charging.

Though the present invention discloses as above with aforesaid preferred embodiment; right its is not in order to limit the present invention; any those of ordinary skills; without departing from the spirit and scope of the present invention; can do some changes and retouching, so protection scope of the present invention is looked this instructions appending claims and is defined.

Claims

1. the driving circuit of the single pixel of penetrating reflective LCD, this single pixel includes a penetration liquid crystal capacitance and a reflection type liquid crystal electric capacity, includes:

One the first transistor, this first transistor have a gate terminal, one source pole end and a drain electrode end;

One transistor seconds, this transistor seconds have a gate terminal, one source pole end and a drain electrode end;

One first signal converter is by the source terminal coupling of one first data line and this first transistor; And

One second signal converter is by the source terminal coupling of one second data line and this transistor seconds;

2. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this first data line is in order to controlling the switch of this first transistor, and drives this penetration liquid crystal capacitance.

3. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this second data line is in order to controlling the switch of this transistor seconds, and drives this reflection type liquid crystal electric capacity.

4. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this first transistor is a thin film transistor (TFT).

5. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this transistor seconds is a thin film transistor (TFT).

6. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this first signal converter is an analog digital signal converter.

7. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this second signal converter is an analog digital signal converter.

8. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this penetration liquid crystal capacitance also is parallel with a storage capacitors.

9. the driving circuit of the single pixel of penetrating reflective LCD as claimed in claim 1, wherein this reflection type liquid crystal electric capacity also is parallel with a storage capacitors.