CN1580885A - Transflective LCD panel - Google Patents

Abstract

The present invention provides a semi-transmissive liquid crystal display panel. The liquid crystal display panel has a transmission area and a reflection area, and includes an upper substrate, a lower substrate, a reflection plate, a first liquid crystal layer and a second liquid crystal layer. The lower substrate is opposite to the upper substrate. The reflection plate is formed on the lower substrate and is located in the reflection area. The first liquid crystal layer and the second liquid crystal layer are sealed between the upper substrate and the lower substrate. The first liquid crystal layer corresponds to the transmission area, and the second liquid crystal layer corresponds to the reflection area. The second liquid crystal layer is doped with a chiral substance. When a voltage is applied, the liquid crystal molecules in the middle section of the first liquid crystal layer are arranged roughly in a manner with a tilt angle θ, and the liquid crystal molecules in the second liquid crystal layer are twisted in addition to the tilt angle.

Description

Transflective LCD panel

technical field

The present invention relates to a transflective liquid crystal display panel (Liquid Crystal Display Panel, LCD Panel), more specifically, relates to a method of making the liquid crystal molecules in the transmissive area and the reflective area have different helical pitches (Pitch) to improve the liquid crystal display. Efficient transflective liquid crystal display panel.

Background technique

With the advancement of technology, transflective liquid crystal display panels are increasingly playing an important role in the market. Especially in the current era where the communication industry is extremely developed, transflective liquid crystal display panels can be applied, for example, in the display screens of mobile phones, so that users can clearly identify the information displayed on the screen in a dark room or in a very bright outdoor. content.

FIG. 1 shows a schematic diagram of a traditional twisted nematic (Twisted Nematic, TN) transflective liquid crystal display panel. The TN transflective liquid crystal display panel 100 has a transmissive area 102 and a reflective area 104 . The transflective liquid crystal display panel 100 also includes an upper substrate 106 , a lower substrate 108 , a reflection plate 110 and a liquid crystal layer 112 . The lower substrate 108 is opposed to the upper substrate 106 . The reflective plate 110 is formed on the lower substrate 108 and located in the reflective area 104 . The liquid crystal layer 112 is sealed between the upper substrate 106 and the lower substrate 108 . In addition, a common electrode (not shown in the figure) is formed on the lower surface of the upper substrate 106 , and a pixel electrode (not shown in the figure) is formed on the upper surface of the lower substrate 108 . An upper polarizer 130 is disposed above the upper substrate 106 , and a lower polarizer 132 and a backlight module 134 are disposed below the lower substrate 108 .

When no voltage is applied to the common electrode and the pixel electrode, the TN transflective liquid crystal display panel 100 is in a bright state (Bright State). At this time, the light 120 provided by the backlight module 134 passes through the lower polarizer 132 , the liquid crystal layer 112 in the penetrating region 102 and the upper polarizer 130 , while the light 122 provided by the external environment passes through the upper polarizer 130 and the reflection region After the liquid crystal layer 112 of 104 is reflected by the reflector 110 , it passes through the liquid crystal layer 112 of the reflective region 104 and the upper polarizer 130 again to emit. It can be seen from FIG. 1 that the light path of the light 122 is twice the light path of the light 120 . In this way, when designing, it is often impossible to take into account the requirements of the transmission mode corresponding to the transmission area 102 and the reflection mode corresponding to the reflection area 104 , and it is difficult to optimize the light efficiency of both the transmission mode and the reflection mode.

In addition, the vertical alignment (Vertical Alignment) transflective LCD panel also encounters the problem of not being able to balance the light efficiency of the reflective mode and the transmissive mode, and the situation is even more serious than that of the TN transflective LCD panel.

Contents of the invention

In view of this, the object of the present invention is to provide a semi-transparent liquid crystal display panel, by doping the liquid crystal layer in the reflection area with a chiral substance, the liquid crystal layer in the reflection area can simultaneously produce a polarization rotation effect (Polarization Rotation) on the light. Effect) or Phase Retardation Effect (Phase Retardation Effect), and can simplify the design, so that both the transmission mode and the reflection mode can easily achieve good light efficiency.

According to the purpose of the present invention, a kind of transflective liquid crystal display panel is proposed. The liquid crystal display panel has a penetrating area and a reflection area. The liquid crystal display panel includes an upper substrate, a lower substrate, a common electrode, a pixel electrode, a reflector, a first four A quarter-wavelength retardation plate and a second quarter-wavelength retardation plate, a first linear polarizer and a second linear polarizer, a first alignment film and a second alignment film, a first liquid crystal layer and a second liquid crystal layer . The lower substrate is opposite to the upper substrate. The common electrode is formed on the first surface of the upper substrate. The pixel electrode is formed on the first surface of the lower substrate and is opposite to the common electrode. The reflection plate is formed on the first surface of the lower substrate and located in the reflection area. The first quarter-wavelength retardation plate is disposed above the second surface of the upper substrate. The first linear polarizing plate is arranged above the first quarter-wavelength retardation plate. The second quarter-wavelength retardation plate is disposed below the second surface of the lower substrate. The second linear polarizing plate is disposed under the second quarter-wavelength retardation plate. The first alignment film covers the common electrode, and the second alignment film covers the pixel electrodes and the reflection plate; and the first liquid crystal layer and a second liquid crystal layer are sealed between the upper substrate and the lower substrate. The first liquid crystal layer corresponds to the transmissive area, and the second liquid crystal layer corresponds to the reflective area. The second liquid crystal layer is doped with chiral substances. Wherein, when a voltage is applied between the common electrode and the pixel electrode, the liquid crystal molecules in the middle section of the first liquid crystal layer are generally arranged in a manner with an inclination angle. The liquid crystal molecules in the second liquid crystal layer also generate twist (Twist) in addition to the tilt angle.

According to another object of the present invention, a transflective liquid crystal display panel is provided. The liquid crystal display panel has a transmissive area and a reflective area. The liquid crystal display panel includes an upper substrate, a lower substrate, a common electrode, a pixel electrode, a reflector, a first quarter-wave retardation plate and a second quarter-wave retardation plate, a first linear polarizer and a second linear polarizer. A linear polarizer, a first vertical alignment film and a second vertical alignment film, and a first liquid crystal layer and a second liquid crystal layer. The lower substrate is opposite to the upper substrate, and there is a gap between the upper substrate and the lower substrate. The common electrode is formed on the first surface of the upper substrate. The pixel electrode is formed on the first surface of the lower substrate and is opposite to the common electrode. The reflection plate is formed on the first surface of the lower substrate and located in the reflection area. The first quarter-wavelength retardation plate is disposed above the second surface of the upper substrate. The first linear polarizing plate is arranged above the first quarter-wavelength retardation plate. The second quarter-wavelength retardation plate is disposed below the second surface of the lower substrate. The second linear polarizing plate is disposed under the second quarter-wavelength retardation plate. The first vertical alignment film covers the common electrode, and the second vertical alignment film covers the pixel electrodes and the reflection plate. The first liquid crystal layer and the second liquid crystal layer are sealed between the upper substrate and the lower substrate and separated by walls. The first liquid crystal layer corresponds to the transmissive area, and the second liquid crystal layer corresponds to the reflective area, and the liquid crystal molecules in the first liquid crystal layer and the second liquid crystal layer are negative type liquid crystal molecules. The second liquid crystal layer is doped with a chiral substance. Wherein, when a voltage is applied between the common electrode and the pixel electrode, the liquid crystal molecules in the middle section of the first liquid crystal layer are generally arranged with a tilt angle, and the liquid crystal molecules in the second liquid crystal layer, in addition to producing a tilt angle, Twist also occurs, and the helical pitch of the liquid crystal molecules in the second liquid crystal layer is greater than or equal to four times the gap when twisted.

In order to make the above-mentioned purposes, features, and advantages of the present invention more obvious and easy to understand, the preferred embodiments are specifically cited below, together with the accompanying drawings, and are described in detail as follows:

Description of drawings

FIG. 1 shows a schematic diagram of a conventional twisted nematic transflective liquid crystal display panel.

FIG. 2A is a schematic diagram of a transflective liquid crystal display panel in a dark state according to the first embodiment of the present invention.

FIG. 2B is a schematic diagram of a transflective liquid crystal display panel in a bright state according to the first embodiment of the present invention.

FIG. 3 shows a transmittance spectrum diagram of a liquid crystal display panel using two polarizers whose light transmission axes are parallel to each other.

Figures 4A and 4B show the relationship between the applied voltage (V) and the transmittance for the liquid crystal display panel shown in Figures 2A and 2B, wherein Figure 4A shows the transmittance of the transmittance region , and what is shown in FIG. 4B is the forward reflectivity of the reflective region.

FIG. 5 is a graph showing the relationship between the applied voltage and the forward reflectivity for a single-gap vertical alignment transflective liquid crystal display panel not doped with chiral substances.

FIG. 6A is a schematic diagram of a transflective liquid crystal display panel in a dark state according to the second embodiment of the present invention.

FIG. 6B is a schematic diagram of the transflective liquid crystal display panel in the bright state according to the second embodiment of the present invention.

Figures 7A and 7B show the relationship between the applied voltage (V) and the transmittance for the liquid crystal display panel shown in Figures 6A and 6B, wherein Figure 7A shows the transmittance of the transmittance region , and what is shown in FIG. 7B is the forward reflectivity of the reflective region.

Detailed ways

The significance of the present invention is that by doping the negative liquid crystal molecules in the reflection area with chiral substances, the liquid crystal layer in the reflection area can simultaneously produce a polarization rotation effect (Polarization Rotation Effect) or a phase retardation effect (Phase Retardation Effect) on light. In this way, the light efficiency of the transmissive area and the reflective area can be improved between the fixed gap between the upper substrate and the lower substrate.

first embodiment

Please refer to Fig. 2A and Fig. 2B, wherein Fig. 2A shows a schematic diagram of a transflective liquid crystal display panel in a dark state (Dark State) according to the first embodiment of the present invention, and Fig. 2B shows is a schematic diagram of the transflective liquid crystal display panel in the Bright State according to the first embodiment of the present invention. The transflective liquid crystal display panel 200 has a transmissive area 202 and a reflective area 204 . The liquid crystal display panel 200 includes an upper substrate 206, a lower substrate 208, a reflector 210, a first quarter-wave retardation film 226A and a second quarter-wave retardation film 226B, a first linear polarizer 228A, and a second linear polarizer 228A. Linear polarizer 228B, first half-wavelength retardation film 230A and second half-wavelength retardation film 230B, first vertical alignment film 242 and second vertical alignment film 244, and first liquid crystal layer 212A and The second liquid crystal layer 212B.

The lower substrate 208 is opposite to the upper substrate 206 , and there is a gap G between the upper substrate 206 and the lower substrate 208 . The common electrode 222 is formed on the first surface 206A of the upper substrate 206 , and the pixel electrode 224 is formed on the first surface 208A of the lower substrate 208 and is opposite to the common electrode 222 . The reflective plate 210 is also formed on the first surface 208A of the lower substrate 208 and located in the reflective area 204 .

The first quarter-wavelength retardation plate 226A is disposed above the second surface 206B of the upper substrate 206 . The first half-wavelength retardation film 230A is disposed above the first quarter-wavelength retardation film 226A, and the first linear polarizer 228A is disposed above the first half-wavelength retardation film 230A. The second quarter-wave retardation plate 226B is disposed below the second surface 208B of the lower substrate 208 . The second half-wavelength retardation film 230B is disposed under the second quarter-wavelength retardation film 226B, and the second linear polarizer 228B is disposed under the second half-wavelength retardation film 230B. The backlight module 234 is disposed under the second linear polarizer 228B to provide the required light L1. Wherein, when the quarter-wavelength retardation plate and the half-wavelength retardation plate are used together, they can be equivalent to a broadband quarter-wavelength retardation plate.

The light transmission axis (Trans-axis) of the first linear polarizer 228A and the second linear polarizer 228B is orthogonal, and the first quarter-wavelength retardation plate 226A and the second quarter-wavelength retardation plate The optical axis (Optical Axis) of 226B is orthogonal, and the first half-wavelength retardation plate 230A and the second half-wavelength retardation plate 230B are also orthogonal. In this embodiment, the angle between the light transmission axis of the first linear polarizer 228A and the X-axis is 0 degrees, the angle between the light transmission axis of the second linear polarizer 228B and the X-axis is 90 degrees, and the first four The included angle between the optical axis and the X-axis of the one-quarter wavelength retardation plate 226A is 75 degrees, the included angle between the optical axis and the X-axis of the second quarter-wavelength retardation plate 226B is -15 degrees, and the first half The angle between the optical axis of the wavelength retardation plate 230A and the X-axis is 15 degrees, and the angle between the optical axis and the X-axis of the second half-wavelength retardation plate 230B is 105 degrees as an example for illustration.

The first vertical alignment film 242 covers the common electrode 222 , and the second vertical alignment film 244 covers the pixel electrodes 224 and the reflection plate 210 . The first liquid crystal layer 212A and the second liquid crystal layer 212B are sealed between the upper substrate 206 and the lower substrate 208 . The first liquid crystal layer 212A corresponds to the transmissive region 202 , and the second liquid crystal layer 212B corresponds to the reflective region 204 . Wherein, the included angle between the rubbing direction of the first vertical alignment film 242 and the second vertical alignment film 244 in the rubbing process (Rubbing) is 180 degrees.

In addition, a color filter (Color Filter) (not shown) is formed on the first surface 206A of the upper substrate 206, and on the first surface 208A of the lower substrate 208, a thin film transistor (Thin Film Transistor, TFT) (not shown) is formed. drawn). The liquid crystal display panel has a plurality of scan lines (Scan Line) and data lines (Data Line) (not shown). The gate of the thin film transistor is controlled by the scan line, the drain of the thin film transistor is connected to the data line, and the source of the thin film transistor is electrically connected to the pixel electrode 224 . The reflection plate 210 and the pixel electrode 224 can be electrically connected to control the movement of the liquid crystal molecules. Wherein, when the scanning line is working, the pixel data is transmitted to the pixel electrode via the data line and the thin film transistor. At this time, the voltage applied between the common electrode 222 and the pixel electrode 224 will change the arrangement of the liquid crystal molecules.

Wherein, the liquid crystal molecules of the first liquid crystal layer 212A and the second liquid crystal layer 212B are negative type liquid crystal molecules. The first liquid crystal layer 212A is isolated from the second liquid crystal layer 212B by a wall 246 . The negative liquid crystal molecules in the second liquid crystal layer 212B are also doped with chiral substances.

When no voltage is applied between the common electrode 222 and the pixel electrode 224, the liquid crystal molecules in the first liquid crystal layer 212A and the second liquid crystal layer 212B are aligned vertically to the first vertical alignment film 242 and the second vertical alignment film 244, At this time, the liquid crystal display panel 200 is in a dark state, as shown in FIG. 2A . When a voltage is applied between the common electrode 222 and the pixel electrode 224, the liquid crystal molecules in the middle section of the first liquid crystal layer 212A are substantially aligned with an inclination angle θ. The twist angle of the liquid crystal molecules in the middle segment is relatively small, and it can be considered that there is no polarization rotation effect. Since the second liquid crystal layer 212B is doped with a chiral substance, the chiral substance will twist the liquid crystal molecules of the second liquid crystal layer 212B. Therefore, the liquid crystal molecules of the second liquid crystal layer 212B are arranged in such a way that in addition to the tilt angle θ, the liquid crystal molecules are also twisted (Twist), which has a larger twist angle, and thus has a polarization rotation effect. At this time, the liquid crystal display panel 200 is in a bright state, as shown in FIG. 2B .

Wherein, the tilt angle θ is the liquid crystal director (LC director), that is, the angle between the long axis direction of the liquid crystal molecules and the normal vector (Y direction) of the first vertical alignment film 242 . The liquid crystal molecules of the second liquid crystal layer 212B are generally twisted in a plane with an angle of about (90-θ) degrees with the XZ plane. In FIG. 2B , the liquid crystal molecules in the middle layer of the second liquid crystal layer 212B are twisted by nearly 90 degrees as an example for illustration. Wherein, the thickness of the liquid crystal layer when the liquid crystal molecules are twisted by 360 degrees is defined as a helical pitch. FIG. 2B takes an example in which the thickness of the second liquid crystal layer 212B is about 1/4 of the helical pitch for illustration.

When the concentration of doped chiral substances is different, the helical pitch of the liquid crystal molecules will also be different. In the present invention, when the concentration of the doped chiral substance makes the helical pitch of the liquid crystal molecules in the second liquid crystal layer 212 larger than 4 times the gap G, a better effect can be obtained. In the present invention, the included angle between the rubbing direction of the first vertical alignment film 242 and the second vertical alignment film 244 is 180 degrees, and doping with a chiral substance at an appropriate concentration, so that the liquid crystal molecules in the middle layer of the second liquid crystal layer 212B are twisted close to 90 degrees. In addition, an ideal helical pitch of liquid crystal molecules in the second liquid crystal layer 212 is about 20-40 micrometers (μm).

Generally speaking, when the light passes through the liquid crystal layer, the light will be affected by the polarization rotation effect or phase retardation effect of the liquid crystal molecules. Please refer to FIG. 2B, in the first liquid crystal layer 212A, light L3 is mainly affected by the phase delay effect of liquid crystal molecules, while in the second liquid crystal layer 212B, light L4 is not only affected by the phase delay effect of liquid crystal molecules, The polarization rotation effect of the liquid crystal molecules also affects the light L4 to a considerable extent.

In order to achieve good light efficiency, the phase difference (Retardation) Δnd must be designed for different modes. For a liquid crystal display panel with only a transmissive mode, the thickness of the liquid crystal layer required for the twisted nematic mode of FIG. 1 is greater than that of the first liquid crystal layer 212A shown in FIGS. 2A and 2B . However, if the second liquid crystal layer 212B shown in FIG. 2A and FIG. 2B is used to realize a transmissive liquid crystal display panel, the liquid crystal layer thickness of the second liquid crystal layer 212B required is also greater than that shown in FIGS. 2A and 2B during implementation. The illustrated thickness of the liquid crystal layer of the first liquid crystal layer 212A may be approximately twice the thickness of the liquid crystal layer of the first liquid crystal layer 212A. Please refer to FIG. 2B, for the second liquid crystal layer 212B used in the reflective region of the present invention, since the optical path length of the light L4 in the reflection mode is twice the optical path length of the light L3 in the transmission mode, the light L4 can be regarded as Penetrating through twice the thickness of the second liquid crystal layer 212B, so when the present invention designs the gap G between the upper substrate 206 and the lower substrate 208 required to achieve good light efficiency for the use of the first liquid crystal layer 212A, the gap G is also suitable for using the second liquid crystal layer 212B, so that good light efficiency can still be obtained after the light L4 is reflected by the reflector 210 .

The polarization of the light rays L1 , L2 , L3 and L4 in FIG. 2A and FIG. 2B is briefly described as follows.

Please refer to Figure 2A. When no voltage is applied between the common electrode 222 and the pixel electrode 224, in the penetrating region 202, the light L1 emitted by the backlight module 234 passes through the second linear polarizer 228B, and the light L1 turns into a direction along Z directionally polarized linearly polarized light. When the light L1 continues to pass through the second half-wavelength retardation plate 230B and the second quarter-wavelength retardation plate 226B, the light L1 turns into circularly polarized light, which is assumed to be right-handed circularly polarized light. When the light L1 continues to pass through the first liquid crystal layer 212A, since the liquid crystal molecules of the first liquid crystal layer 212A are aligned vertically to the first vertical alignment film 242, no phase retardation effect will be generated on the light L1, so the light L1 is still For right-handed circularly polarized light. When the light L1 continues to pass through the first quarter-wavelength retardation plate 226A and the first half-wavelength retardation plate 230A, the light L1 turns into linearly polarized light polarized along the Z direction, and is linearly polarized by the first linearly polarized light Plate 228A blocks. At this time, the penetration region 202 is in a dark state.

Please refer to FIG. 2A again. When no voltage is applied between the common electrode 222 and the pixel electrode 224, in the reflective region 204, after the light L2 incident from the surrounding environment passes through the first linear polarizer 228A, the light L2 is converted to be polarized along the X direction of linearly polarized light. When the light L2 continues to pass through the first half-wavelength retardation plate 230A and the first quarter-wavelength retardation plate 226A, the light L2 turns into left-handed circularly polarized light. When the light L2 continues to pass through the second liquid crystal layer 212B, since the liquid crystal molecules of the second liquid crystal layer 212B are arranged in a manner perpendicular to the first vertical alignment film 242, no phase retardation effect will be produced on the light L2, so the light L2 is still For left-handed circularly polarized light. After the light L2 is reflected by the reflector 210, the light L2 turns into a right-handed polarized light. When the light L2 passes through the first quarter-wavelength retardation plate 226A and the first half-wavelength retardation plate 230A again, the light L2 turns into a linearly polarized light polarized along the Z direction, and is linearly polarized by the first linearly polarized light Plate 228A blocks. At this time, the reflective region 204 is also in a dark state.

Please refer to Figure 2B. When a voltage is applied between the common electrode 222 and the pixel electrode 224, the liquid crystal molecules of the first liquid crystal layer 212A will be inclined due to the influence of the electric field, and the present invention will design the phase difference Δnd of the liquid crystal molecules of the inclined first liquid crystal layer 212A is a value equal to one-half the wavelength (λ/2). In the transmission area 202, the light L3 emitted by the backlight module 234 passes through the second linear polarizer 228B, the second half-wave retardation film 230B and the second quarter-wave retardation film 226B, Light L3 turns into right-handed circularly polarized light. When the light L3 continues to pass through the first liquid crystal layer 212A, the light L3 will turn into left-handed circularly polarized light. When the light L3 continues to pass through the first quarter-wavelength retardation plate 226A and the first half-wavelength retardation plate 230A, the light L3 turns into linearly polarized light polarized along the X direction and can pass through the first linearly polarized light Plate 228A. At this time, the penetrating region 202 is in a bright state.

Please refer to FIG. 2B again. When a voltage is applied between the common electrode 222 and the pixel electrode 224, the liquid crystal molecules of the second liquid crystal layer 212B will be inclined due to the influence of the electric field. The liquid crystal molecules of the second liquid crystal layer 212B can cause the light to produce polarization rotation and phase retardation at the same time. In the present invention, the influence of the inclined liquid crystal molecules of the second liquid crystal layer 212B on the polarization state of the incident light is equivalent to the phase difference value Δnd being approximately equal to Quarter wavelength (λ/4) wave plate. In the reflective area 204 , after the light L4 incident from the surrounding environment passes through the first linear polarizer 228A, the light L4 is converted into linearly polarized light polarized along the X direction. When the light L4 continues to pass through the first half-wavelength retardation plate 230A and the first quarter-wavelength retardation plate 226A, the light L4 turns into a left-handed circularly polarized light. When light L4 continues to pass through the second liquid crystal layer 212B, is reflected by the reflector 210, and passes through the second liquid crystal layer 212B again, the effect of passing through the second liquid crystal layer 212B twice and being reflected by the reflector 210 will make the light L4 still is left-handed polarized light. After the light L4 passes through the first quarter-wavelength retardation plate 226A and the first half-wavelength retardation plate 230A again, the light L4 turns into linearly polarized light polarized along the X direction and can pass through the first linearly polarized light Plate 228A. At this time, the reflection area 204 will be in a bright state.

Now, the method of doping the chiral substance in the second liquid crystal layer 212B and the method of forming the partition walls 246 are described as follows.

The method of doping the chiral material in the second liquid crystal layer 212B is as follows: firstly, doping the tunable chiral material (Tunable Chiral Material, TCM) in the first liquid crystal layer 212A and the second liquid crystal layer 212B simultaneously. Then, exposure is performed from the back of the liquid crystal display panel 200 (ie, the back of the reflection plate 210 ), so that the tunable chiral substance in the penetrating region 202 is unwound. By making the first liquid crystal layer 212A and the second liquid crystal layer 212B obtain different exposure amounts, the effective concentration of the chiral substance in the second liquid crystal layer 212B is greater than the effective concentration of the chiral substance in the first liquid crystal layer 212A. This doping method will make both the first liquid crystal layer 212A and the second liquid crystal layer 212B doped with chiral substances, however, the effective concentration of the chiral substances in the first liquid crystal layer 212A can be made very small, and The effect of twisting the liquid crystal molecules of the first liquid crystal layer 212A is negligible to obtain the first embodiment of the present invention.

However, even if the liquid crystal molecules in the first liquid crystal layer 212A are twisted, as long as the helical pitch corresponding to the first liquid crystal layer 212A is larger than the helical pitch corresponding to the second liquid crystal layer 212b, the purpose of the present invention can also be achieved.

The partition wall 246 can be formed in the following ways. (1) Adding an appropriate amount of monomer (Monomer) to the liquid crystal layer, and forming a partition wall 246 between the transmissive area 202 and the reflective area 204 by using a photolithographic mask and an exposure process. (2) A partition wall 246 is formed between the penetrating area 202 and the reflecting area 204 by means of exposing, developing, and etching a photoresist or an organic material.

In addition, the twist angle of the liquid crystal molecules can also be adjusted by adjusting the elastic coefficient of the liquid crystal.

The simulation results of the first embodiment of the present invention are described as follows.

Please refer to FIG. 3 , which shows a transmittance spectrum diagram of a liquid crystal display panel using two polarizers whose light transmission axes are parallel to each other. The horizontal axis is the wavelength of light, while the vertical axis is the transmittance. It can be seen from FIG. 3 that the upper limit of the transmittance of the liquid crystal display panel at this time is 0.35.

Please refer to Figures 4A and 4B, which show the relationship between the applied voltage (V) and the transmittance for the liquid crystal display panel shown in Figures 2A and 2B, where Figure 4A shows the transmittance The transmittance of the region, while the forward reflectivity of the reflective region is shown in Figure 4B. 4A and 4B use the liquid crystal of model MJ961213, the gap G between the upper substrate 206 and the lower substrate 208 is 4.5 microns, the helical pitch of the second liquid crystal layer 212B in the reflective region 204 is 16 microns, and the liquid crystal molecules are tilted when no voltage is applied. The angle is 89 degrees as an example for simulation. When the maximum operating voltage is 4V, the transmittance of the transmissive region is about 0.33, and the forward reflectivity of the reflective region is about 0.34, as shown in FIG. 4A and FIG. 4B respectively. It can be seen that in the first embodiment of the present invention, when the transmissive region 202 and the reflective region 204 have the same gap G between the upper substrate 206 and the lower substrate 208, both the transmissive region 202 and the reflective region 204 can achieve High transmittance and high light efficiency.

Conversely, if the second liquid crystal layer 212B of the liquid crystal display panel shown in FIGS. 2A and 2B is not doped with a chiral substance (that is, a conventional single gap (single gap) vertical alignment type transflective liquid crystal display panel) , the forward reflectivity of the reflective region 204 will be severely reduced. Please refer to FIG. 5 , which shows the relationship between the applied voltage (V) and the forward reflectivity for a vertically aligned transflective liquid crystal display panel with a single gap not doped with chiral substances. It can be seen from FIG. 5 that when the voltage is greater than 2.9V, the higher the applied voltage, the lower the forward reflectivity will be. It can be seen that the vertical alignment transflective liquid crystal display panel with a single gap cannot achieve good transmittance in both the reflection area and the transmission area. However, the present invention does solve the problem that the traditional liquid crystal display panel cannot take into account the light efficiency of the reflective mode and the transmissive mode.

second embodiment

In the first embodiment, two quarter-wavelength retardation plates and two half-wavelength retardation plates are used to be equivalent to two wide-band quarter-wavelength retardation plates. Whereas, in the second embodiment, instead of using a half-wave retardation plate, only two quarter-wave retardation plates are used. In this way, the object of the present invention can also be achieved.

Please refer to FIG. 6A and FIG. 6B, wherein, FIG. 6A shows a schematic diagram of a transflective liquid crystal display panel in a dark state according to the second embodiment of the present invention, and FIG. 6B shows the second embodiment of the present invention. A schematic diagram of the transflective liquid crystal display panel of the embodiment in a bright state. In the transflective liquid crystal display panel 600 , the first quarter-wavelength retardation plate 626A is disposed above the second surface 606B of the upper substrate 606 . The first linear polarizer 628A is disposed above the first quarter-wavelength retardation plate 626A. The second quarter-wave retardation plate 626B is disposed below the second surface 608B of the lower substrate 608 . The second linear polarizer 628B is disposed under the second quarter-wave retardation plate 626B.

The first linear polarizer 628A is perpendicular to the light transmission axis (Trans-axis) of the second linear polarizer 628B, and the first quarter-wavelength retardation plate 226A is perpendicular to the second quarter-wavelength retardation plate 226B. Optical axis (Optical Axis) is also orthogonal. In this embodiment, assuming that the angle between the light transmission axis of the first linear polarizer 628A and the X-axis is 0 degrees, and the angle between the light transmission axis of the second linear polarizer 628B and the X-axis is 90 degrees, the first four The angle between the optical axis of the quarter-wavelength retardation plate 626A and the X-axis is 45 degrees, and the angle between the optical axis and the X-axis of the second quarter-wavelength retardation plate 626B is -45 degrees.

The simulation results of the second embodiment of the present invention are now described as follows.

Please refer to FIG. 7A and FIG. 7B, which shows the relationship between the applied voltage (V) and the transmittance for the liquid crystal display panel shown in FIG. 6A and 6B. Among them, FIG. 7A shows the transmittance The transmittance of the region, while the forward reflectivity of the reflective region is shown in Figure 7B. 7A and 7B use the liquid crystal of model MJ961213, the gap G' between the upper substrate 606 and the lower substrate 608 is 4.2 microns, the helical pitch of the liquid crystal molecules in the second liquid crystal layer 612B of the reflective region 604 is 16 microns, and the liquid crystal molecules are not When the voltage is applied, the inclination angle is 89 degrees as an example for simulation. When the maximum operating voltage is 4V, the transmittance of the transmissive region 602 is about 0.3, and the forward reflectivity of the reflective region 604 is about 0.34, as shown in FIG. 7A and FIG. 7B respectively. It can be seen that, in the second embodiment of the present invention, when the transmissive region 602 and the reflective region 604 have the same gap G′ between the upper substrate 606 and the lower substrate 608, the transmissive region 602 and the reflective region 604 are also both Can achieve high transmittance and high light efficiency.

In the preferred embodiment of the present invention, although the included angle between the rubbing directions of the first vertical alignment film and the second vertical alignment film in the rubbing process is 180 degrees as an example for illustration, the present invention is not limited thereto. The included angle between the rubbing directions of the first vertical alignment film and the second vertical alignment film in the grinding process of the present invention may be any angle other than 180 degrees. Different included angles will cause different twist angles of the liquid crystal molecules.

The invention has the advantage that it can effectively simplify the design of the transflective liquid crystal display panel, so that both the transmissive mode and the reflective mode of the transflective liquid crystal display panel can easily achieve better light efficiency.

In summary, although the present invention has been described above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various changes without departing from the spirit and scope of the present invention. and modification, so the protection scope of the present invention should be determined by the content defined in the claims.

Claims (13)

1. A transflective liquid crystal display panel, the liquid crystal display panel has a penetrating area and a reflection area, and the liquid crystal display panel comprises: upper substrate; The lower substrate is opposite to the upper substrate; a common electrode formed on the first surface of the upper substrate; A pixel electrode is formed on the first surface of the lower substrate and is opposite to the common electrode; a reflective plate formed on the first surface of the lower substrate and located in the reflective area; a first quarter-wavelength retardation plate configured above the second surface of the upper substrate; The first linear polarizing plate is configured above the first quarter-wavelength retardation plate; a second quarter-wavelength retardation plate configured below the second surface of the lower substrate; The second linear polarizer is configured under the second quarter-wave retardation plate; a first alignment film and a second alignment film, the first alignment film covers the common electrode, and the second alignment film covers the pixel electrodes and the reflector; and The first liquid crystal layer and the second liquid crystal layer are sealed between the upper substrate and the lower substrate, the first liquid crystal layer corresponds to the transmissive area, and the second liquid crystal layer corresponds to the reflective area, and the second liquid crystal layer is doped with a chiral substance ; Wherein, when a voltage is applied between the common electrode and the pixel electrode, the liquid crystal molecules in the middle section of the first liquid crystal layer are generally arranged with a tilt angle, and the liquid crystal molecules in the second liquid crystal layer, in addition to producing a tilt angle, Torsion also occurs. 2. The liquid crystal display panel as claimed in claim 1, wherein the first liquid crystal layer is separated from the second liquid crystal layer by a partition wall. 3. The liquid crystal display panel as claimed in claim 1, wherein there is a gap between the upper substrate and the lower substrate, and the helical pitch of the liquid crystal molecules in the second liquid crystal layer is greater than or equal to four times the gap when twisted. 4. The liquid crystal display panel as claimed in claim 3, wherein the helical pitch is about 20-40 microns. 5. The liquid crystal display panel according to claim 1, wherein the chiral substance is an adjustable chiral substance, and the first liquid crystal layer is also doped with the adjustable chiral substance, wherein, by making the first liquid crystal layer and The second liquid crystal layer receives different exposure amounts, so that the effective concentration of the chiral substance in the second liquid crystal layer is greater than the effective concentration of the chiral substance in the first liquid crystal layer. 6. The liquid crystal display panel according to claim 1, wherein both the first alignment film and the second alignment film are vertical alignment films, and the liquid crystal molecules of the first liquid crystal layer and the second liquid crystal layer are negative type liquid crystal molecules , when no voltage is applied between the common electrode and the pixel electrode, the liquid crystal molecules of the first liquid crystal layer and the second liquid crystal layer are perpendicular to the first vertical alignment film. 7. The liquid crystal display panel according to claim 1, wherein the liquid crystal display panel further comprises a first half-wavelength phase difference plate and a second half-wavelength phase difference plate, and the first half-wavelength phase difference plate is The wavelength retardation plate is disposed between the first quarter-wavelength retardation plate and the first linear polarizing plate, and the second half-wavelength retardation plate is disposed between the second quarter-wavelength retardation plate and the first linear polarizer. between two linear polarizers. 8. A transflective liquid crystal display panel, the liquid crystal display panel has a penetrating area and a reflection area, and the liquid crystal display panel includes: upper substrate; The lower substrate is opposite to the upper substrate, and there is a gap between the upper substrate and the lower substrate; a common electrode formed on the first surface of the upper substrate; A pixel electrode is formed on the first surface of the lower substrate and is opposite to the common electrode; a reflective plate formed on the first surface of the lower substrate and located in the reflective area; a first quarter-wavelength retardation plate configured above the second surface of the upper substrate; The first linear polarizing plate is configured above the first quarter-wavelength retardation plate; a second quarter-wavelength retardation plate configured below the second surface of the lower substrate; The second linear polarizer is configured under the second quarter-wave retardation plate; a first vertical alignment film and a second vertical alignment film, the first vertical alignment film covers the common electrode, and the second vertical alignment film covers the pixel electrode and the reflector; and The first liquid crystal layer and the second liquid crystal layer are sealed between the upper substrate and the lower substrate and separated by a partition wall. The first liquid crystal layer corresponds to the transmissive area, while the second liquid crystal layer corresponds to the reflective area. The first liquid crystal layer corresponds to the reflective area. The liquid crystal molecules in the second liquid crystal layer are negative liquid crystal molecules, and the second liquid crystal layer is doped with a chiral substance; Wherein, when a voltage is applied between the common electrode and the pixel electrode, the liquid crystal molecules in the middle section of the first liquid crystal layer are generally arranged with a tilt angle, and the liquid crystal molecules in the second liquid crystal layer, in addition to producing a tilt angle, Twisting is also generated, and the helical pitch when the liquid crystal molecules of the second liquid crystal layer are twisted is equal to or greater than four times the gap. 9. The liquid crystal display panel as claimed in claim 8, wherein the helical pitch is about 20-40 microns. 10. The liquid crystal display panel as claimed in claim 8, wherein the liquid crystal display panel further comprises a first 1/2 wavelength phase difference plate and a second 1/2 wavelength phase difference plate, and the first 1/2 wavelength phase difference plate The wavelength retardation plate is disposed between the first quarter-wavelength retardation plate and the first linear polarizing plate, and the second half-wavelength retardation plate is disposed between the second quarter-wavelength retardation plate and the first linear polarizer. between two linear polarizers. 11. A transflective liquid crystal display panel, the liquid crystal display panel has a penetrating area and a reflection area, and the liquid crystal display panel includes: upper substrate; The lower substrate is opposite to the upper substrate, and there is a gap between the upper substrate and the lower substrate; a common electrode formed on the first surface of the upper substrate; A pixel electrode is formed on the first surface of the lower substrate and is opposite to the common electrode; a reflective plate formed on the first surface of the lower substrate and located in the reflective area; a first quarter-wavelength retardation plate configured above the second surface of the upper substrate; The first linear polarizing plate is configured above the first quarter-wavelength retardation plate; a second quarter-wavelength retardation plate configured below the second surface of the lower substrate; The second linear polarizer is configured under the second quarter-wave retardation plate; a first vertical alignment film and a second vertical alignment film, the first vertical alignment film covers the common electrode, and the second vertical alignment film covers the pixel electrodes and the reflector; and The first liquid crystal layer and the second liquid crystal layer are sealed between the upper substrate and the lower substrate and separated by a partition wall. The first liquid crystal layer corresponds to the transmissive area, while the second liquid crystal layer corresponds to the reflective area. The first liquid crystal layer The liquid crystal molecules in the first liquid crystal layer and the second liquid crystal layer are negative type liquid crystal molecules, the first liquid crystal layer is doped with a chiral substance with a first concentration, and the second liquid crystal layer is doped with a chiral substance with a second concentration; Wherein, the second concentration is greater than the first concentration. 12. The liquid crystal display panel according to claim 11, wherein the chiral substance is an adjustable chiral substance, and by making the first liquid crystal layer and the second liquid crystal layer obtain different exposure amounts, the second concentration is greater than the first concentration. 13. The liquid crystal display panel as claimed in claim 11, wherein the liquid crystal display panel further comprises a first half-wavelength retardation plate and a second half-wavelength retardation plate, and the first half-wavelength retardation plate The wavelength retardation plate is disposed between the first quarter-wavelength retardation plate and the first linear polarizer, and the second half-wavelength retardation plate is disposed between the second quarter-wavelength retardation plate and the first linear polarizer. between two linear polarizers.

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