JP2005345799A - Visual field angle control panel and display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To limit the visual field angle of a display screen according to the situation. <P>SOLUTION: A visual field angle control panel is provided with light transmissive substrates T1 and T2, a liquid crystal layer LB interposed between the substrates T1 and T2 and first and second polarizing plates 6 and 11 disposed on the outer sides of the substrates T1 and T2 to the liquid crystal layer LB, respectively. The substrates T1 and T2 include electrodes EL1 and EL2 disposed on substrates 7 and 9 so as to face each other and applying an electric field to the liquid crystal layer LB and alignment layers 8 and 10, respectively covering the electrodes EL1 and EL2 adjacently to the liquid crystal layer LB. The alignment layers 8 and 10 are constituted by the combination of first and second alignment sections A1 and A2, respectively cooperating with the polarizing plates 6 and 11 and regulating the alignment direction of liquid crystal molecules for reducing the transmittance of light traveling in direction inclined to one side and to the other side, from the front direction nearly vertical to the surfaces of the substrates, when voltage is applied between the electrodes EL1 and EL2, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a viewing angle control panel that limits the viewing angle of a display image and a display device including the viewing angle control panel.

  For example, liquid crystal display devices are widely used as monitor displays for personal computers, portable information terminals, televisions, car navigation systems, and the like.

  A liquid crystal display device generally includes a display panel including a matrix array of a plurality of liquid crystal pixels, and a control circuit that controls the display panel. A typical display panel has a structure in which a liquid crystal layer is sandwiched between an array substrate and a counter substrate. The array substrate has a plurality of pixel electrodes arranged in a matrix, and the counter substrate has a common electrode facing the pixel electrodes. The pixel electrode and the common electrode constitute a liquid crystal pixel together with the pixel region of the liquid crystal layer disposed between these electrodes, and the liquid crystal molecule arrangement in the pixel region is controlled by an electric field corresponding to the voltage between the pixel electrode and the common electrode.

  In general, as a characteristic of a liquid crystal display panel, a viewing angle dependency is known in which luminance changes depending on a direction in which an image is observed. For this reason, research has been actively conducted to increase the viewing angle of liquid crystal display panels so that images can be observed with uniform brightness from any direction. On the other hand, for example, in the use of a monitor display incorporated in an automatic teller machine (ATM) of a bank or the like, a display image is not shown except for customers who deposit or withdraw cash in front of the monitor display. On the contrary, a narrow viewing angle is required. Similarly, a monitor display of a mobile phone is also required to have a narrow viewing angle with respect to creation and browsing of mail.

Conventionally, a light emission angle limiting filter is known as a technique for narrowing the viewing angle of a liquid crystal display panel (see, for example, Patent Document 1). The light emission limiting filter allows light to pass through in the thickness direction of the sheet-like body, that is, the direction orthogonal to the plane of the sheet-like body, but does not pass light having an angle greater than the waveguide angle of the optical waveguide. . Therefore, by arranging this filter so as to overlap the display screen, the image displayed on the display screen can be viewed from the front, but cannot be viewed from other directions.
JP 2002-297044 A

  By the way, in recent years, bank ATMs have been installed in convenience stores and the like, making it possible to use ATMs for shopping. In such installation locations, ATM monitor displays are often used to display convenience store advertisements. However, when the light emission limiting filter as described above is arranged so as to overlap the display screen, the result is that the advertisement cannot be shown except for a specific customer who uses the ATM.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a viewing angle control panel and a display device capable of substantially limiting the viewing angle of a display screen depending on the situation.

  According to the present invention, there is provided a viewing angle control panel that selectively limits a viewing angle of a display screen, a pair of light transmissive substrates, a liquid crystal layer sandwiched between the pair of light transmissive substrates, and a liquid crystal layer The first and second polarizing plates are respectively disposed outside the pair of light transmissive substrates, and the pair of light transmissive substrates are disposed on the pair of substrates so as to face each other, and an electric field is applied to the liquid crystal layer. And first and second alignment films that cover the first and second electrodes, respectively, adjacent to the liquid crystal layer, and the first and second alignment films are first and second polarizations, respectively. In cooperation with the plate, the orientation direction of the liquid crystal molecules reduces the light transmittance toward the direction inclined to the one side from the front direction substantially perpendicular to the substrate surface when a voltage is applied between the first and second electrodes. The first alignment portion to be defined and substantially perpendicular to the substrate surface when a voltage is applied Combinations The configured viewing angle control panel and the second alignment portion defining the alignment direction of liquid crystal molecules to reduce the transmittance of light toward the direction which is inclined to the other side is provided with respect to the surface orientation.

  In addition, according to the present invention, a display panel that displays an image on a display screen and a viewing angle control panel that is placed on the display panel and limits the viewing angle of the image displayed on the display panel are provided. The panel includes a pair of light transmissive substrates, a liquid crystal layer sandwiched between the pair of light transmissive substrates, and first and second polarizing plates respectively disposed outside the pair of light transmissive substrates with respect to the liquid crystal layer. The first and second electrodes are arranged on the pair of substrates so as to face each other and apply an electric field to the liquid crystal layer, and the first and second adjacent to the liquid crystal layer. The first and second alignment films each covering the electrodes, the first and second alignment films cooperate with the first and second polarizing plates, and the substrate surface during voltage application to apply a voltage between the first and second electrodes From the front direction almost perpendicular to the direction toward one side A first alignment unit that aligns liquid crystal molecules in a direction that reduces light transmittance, and a direction that reduces light transmittance toward a direction inclined to the other side with respect to a front direction substantially perpendicular to the substrate surface when a voltage is applied. A display device is provided that is configured in combination with a second alignment portion that aligns liquid crystal molecules.

  In these viewing angle control panels and display devices, light is applied in a direction inclined to one side and a direction inclined to the other side from a front direction substantially perpendicular to the substrate surface when a voltage is applied between the first and second electrodes. The transmittance of the film partially decreases. That is, the image information of the display image is partially lost in directions other than the front. Conversely, unless a voltage is applied between the first and second electrodes, the image information of the display image is not impaired even in directions other than the front. Therefore, it is possible to substantially limit the viewing angle of the display screen depending on the situation.

  Hereinafter, a display device according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 schematically shows a cross-sectional structure of the display device, and FIG. 2 schematically shows a circuit structure of the display device shown in FIG. The display device 1 includes a display panel DSP that displays an image, a viewing angle control panel VAC that is arranged to overlap the display panel DSP and selectively restricts the viewing angle of an image displayed on the display panel DSP, and an external PCB substrate, for example. And a control unit CNT for controlling the display panel DSP and the viewing angle control panel VAC.

  The display panel DSP has a structure in which a liquid crystal layer LA is sandwiched between a light transmissive substrate (array substrate) AR and a light transmissive substrate (counter substrate) CT. The array substrate AR has, for example, a plurality of pixel electrodes PE arranged in a matrix on a transparent insulating substrate 1 such as glass, and an alignment film 2 that covers these pixel electrodes PE. Further, the counter substrate CT includes a common electrode CE that is disposed on a transparent insulating substrate 3 such as glass and is opposed to the plurality of pixel electrodes PE, and an alignment film 4 that covers the common electrode CE. The alignment axes of the alignment films 2 and 4 are set so as to be shifted from each other by a predetermined angle by rubbing treatment. The array substrate AR and the counter substrate CT are bonded together by the outer edge seal member SL with the alignment films 2 and 4 facing inside. The liquid crystal layer LA is obtained by injecting a nematic liquid crystal material from a liquid crystal injection port which is an opening of the outer edge seal member SL after bonding the array substrate AR and the counter substrate CT, and sealing with a sealing member after this injection. . The nematic liquid crystal material has, for example, positive dielectric anisotropy and is twisted and aligned between the array substrate AR and the counter substrate CT. Further, the polarizing plate 5 is attached to the array substrate AR on the side opposite to the alignment film 2, and the polarizing plate 6 is attached to the counter substrate CT on the side opposite to the alignment film 4. The gap between the array substrate AR and the counter substrate CT is maintained constant by, for example, a spherical spacer SP. Each pixel electrode PE and common electrode CE are made of a transparent electrode material such as ITO, for example, and are arranged between the pixel electrode PE and common electrode CE and controlled to a liquid crystal molecular arrangement corresponding to the electric field from these electrodes PE and CE. A liquid crystal pixel PX is configured together with the region of the liquid crystal layer LA.

  The viewing angle control panel VAC has a structure in which a liquid crystal layer LB is sandwiched between the light transmissive substrate T1 and the light transmissive substrate T2. The light transmissive substrate T1 includes a first electrode EL1 that is disposed so as to be spread over the transparent insulating substrate 7 such as glass, and an alignment film 8 that covers the first electrode EL1. The light-transmitting substrate T2 includes a second electrode EL2 disposed on a transparent insulating substrate 9 such as glass and facing the first electrode EL1, and an alignment film 10 covering the second electrode EL2. The alignment axes of the alignment films 8 and 10 are set so as to be shifted from each other by a predetermined angle by rubbing treatment. The light transmissive substrates T1 and T2 are bonded together by the outer edge seal member SL with the alignment films 8 and 10 inside. Similarly to the display panel DSP, the liquid crystal layer LB is injected with a nematic liquid crystal material from a liquid crystal injection port which is an opening of the outer edge seal member SL after the light transmissive substrate T1 and the light transmissive substrate T2 are bonded together. It is obtained by sealing with a stop member. The nematic liquid crystal material has a positive dielectric anisotropy, for example, and is twisted and aligned between the light-transmitting substrates T1 and T2. Further, the polarizing plate 5 is attached to the light-transmitting substrate T1 on the side opposite to the alignment film 8, and the polarizing plate 11 is attached to the light-transmitting substrate T2 on the side opposite to the alignment film 10. Note that the gap between the light-transmitting substrates T1 and T2 is maintained constant by, for example, a spherical spacer SP as in the display panel DSP. The first electrode EL1 and the second electrode EL2 are made of a transparent electrode material such as ITO, and the liquid crystal layer LB is controlled to a liquid crystal molecular arrangement corresponding to the electric field from the first electrode EL1 and the second electrode EL2.

  Here, the alignment films 8 and 10 cooperate with the polarizing plates 6 and 11 and are tilted to one side from the front direction substantially perpendicular to the substrate surface when a voltage is applied between the first and second electrodes EL1 and EL2. Alignment portion A1 for aligning liquid crystal molecules in a direction that reduces the light transmittance toward the direction and the light transmittance toward the direction inclined to the other side with respect to the front direction substantially perpendicular to the substrate surface when a voltage is applied. It is comprised by the combination with 2nd orientation part A2 which orientates a liquid crystal molecule to direction.

  As shown in FIG. 2, the actual array substrate AR is further arranged along a plurality of gate lines Y (Y1 to Ym) arranged along a row of the plurality of pixel electrodes PE and a column of the plurality of pixel electrodes PE. A plurality of source lines X (X1 to Xn), a pixel switching element W arranged in the vicinity of the intersection position of the gate lines Y and the source lines X, and a plurality of gate lines Y at a rate of one in one horizontal display period. A vertical driver YD for sequentially driving and a horizontal driver XD for driving a plurality of source lines X while each gate line Y is driven are provided. Each pixel switching element W is made of, for example, a polysilicon thin film transistor. In this case, the gate of the thin film transistor is connected to one gate line Y, and the source-drain path is connected between one source line X and one pixel electrode PE. Note that the vertical driver YD is configured using a polysilicon thin film transistor formed simultaneously with the pixel switching element W in the same process. The horizontal driver XD is an integrated circuit (IC) chip mounted on the array substrate AR by COG (Chip On Glass) technology. All the pixels PX have an auxiliary capacitor Cs. These auxiliary capacitors Cs are obtained by electrically connecting a plurality of auxiliary capacitor lines capacitively coupled to the pixel electrodes PE in a plurality of rows on the array substrate AR side to the common electrode CE.

  The control unit CNT includes a controller 15, a common voltage generation circuit 16, a gradation reference voltage generation circuit 17, a viewing angle control panel drive circuit 18, and a switch control circuit 19. The controller 15 converts an analog RGB video signal supplied from the outside into a digitized video signal VIDEO, and displays the image on the display panel DP as an image, a common voltage generation circuit 16, a gradation reference voltage generation circuit 17, and a vertical driver YD. The horizontal driver XD is controlled. The common voltage generation circuit 16 generates a common voltage Vcom for the common electrode CE on the counter substrate CT. The gradation reference voltage generation circuit 17 generates a first predetermined number of gradation reference voltages VREF used for converting a digital display signal obtained for each pixel PX from the digital video signal VIDEO into a pixel voltage. The pixel voltage is a voltage applied to the pixel electrode PE with reference to the potential of the common electrode CE.

  The controller 15 controls the control signal CTY for sequentially selecting a plurality of gate lines Y for each vertical scanning period and the display signal for the pixels PX for one row included in the video signal VIDEO for each horizontal scanning period (1H). A control signal CTX or the like for assigning each to a plurality of source lines X is generated. Here, the control signal CTX includes a horizontal start signal that is a pulse generated every horizontal scanning period (1H) and a horizontal clock signal that is a pulse generated by the number of source lines in each horizontal scanning period. The control signal CTY is supplied from the controller 15 to the vertical driver YD, and the control signal CTX is supplied from the controller 15 to the horizontal driver XD together with the digital video signal VIDEO.

  The vertical driver YD sequentially selects a plurality of gate lines Y under the control of the control signal CTY, and supplies a scanning signal for making the pixel switching element W conductive to the selection gate line Y. In the present embodiment, the plurality of pixels PX are sequentially selected one row at a time in one horizontal scanning period.

  On the other hand, the horizontal driver XD sequentially converts the digital video signal VIDEO into serial-parallel conversion under the control of the control signal CTX, and converts the display signal for the pixels PX for one row into an analog pixel voltage with reference to the gradation reference voltage VREF.

  That is, in the display panel DSP, the vertical driver YD outputs a scanning signal to one gate line Y every horizontal scanning period, and the horizontal driver XD sets the pixel voltage for the pixels PX for one row every horizontal scanning period. Output to the source lines X1 to Xn in parallel. The pixel voltages on these source lines X1 to Xn are respectively supplied to the corresponding pixel electrodes PE via one row of pixel switching elements W driven by the scanning signal. The common voltage Vcom is output from the common voltage generation circuit 16 to the common electrode CE in synchronization with the output timing of the pixel voltage. In the common voltage generation circuit 16, the polarity of the common voltage Vcom is alternately inverted every horizontal scanning period, for example. Accordingly, in the horizontal driver XD, the pixel voltage is inverted in polarity with respect to the center level of the common voltage Vcom. In this way, the display panel DSP controls the transmittance of the liquid crystal layer for each pixel corresponding to the video signal, thereby modulating the backlight light by the liquid crystal layer LA and displaying an image on the polarizing plate 6 serving as a display screen. To do.

  The viewing angle control panel drive circuit 18 is turned on / off by an external control signal or a switch control circuit 19, and a drive voltage whose polarity is periodically inverted is applied between the first electrode EL1 and the second electrode EL2 of the viewing angle control panel VAC. By applying, it is possible to limit the viewing direction of the image displayed on the display screen of the display panel DSP to the vicinity of the front. The switch control circuit 19 is configured to control the viewing angle control panel drive circuit 18 in response to a sensor input signal from, for example, a human sensor.

  FIG. 3 shows an example of the circuit configuration of the viewing angle control panel driving circuit 18 shown in FIG. The viewing angle control panel driving circuit 18 generates a clock signal 21 that generates a clock signal that is a timing for polarity inversion of the first electrode EL1 and the second electrode EL2, and the amplitude of the clock signal obtained from the clock generation circuit 21 is the first electrode. An amplitude adjustment circuit 22 that adjusts as a drive voltage applied between EL1 and the second electrode EL2, and an on / off switch circuit 23 that selectively supplies the drive voltage obtained from the amplitude adjustment circuit 22 to the viewing angle control panel VAC. including. As the drive voltage is supplied, the first electrode EL1 and the second electrode EL2 are set to potentials whose polarity is inverted at a period equal to one frame (vertical scanning) period, for example, as shown in FIG. The potential difference between the electrode EL1 and the second electrode EL2 is always constant. In the viewing angle control panel VAC, the orientation portions A1 and orientation portions A2 described above are arranged two-dimensionally and alternately, and the orientation portion A1 has a direction inclined to one side from the front direction substantially perpendicular to the substrate surface. The second light transmitting portion A2 reduces the light transmittance toward the direction inclined to the other side with respect to the front direction substantially perpendicular to the substrate surface. The transmittance decreases as the drive voltage adjusted by the amplitude adjustment circuit 22 increases. Each of the alignment portion A1 and the alignment portion A2 has a square planar shape including, for example, 10 × 10 pixels. As a result, the display image is masked with the checker pattern shown in FIG. 5 for the direction inclined to one side with respect to the front direction, and the check pattern shown in FIG. 6 is masked for the direction inclined to the other side with respect to the front direction. .

  In the present embodiment, when a voltage is applied between the first and second electrodes EL1, EL2, light is transmitted in a direction inclined to one side and a direction inclined to the other side from the front direction substantially perpendicular to the substrate surface. Since the rate is partially reduced, the image information of the display image is partially lost in directions other than the front. Conversely, unless a voltage is applied between the first and second electrodes, the image information of the display image is not impaired even in directions other than the front. Therefore, it is possible to substantially limit the viewing angle of the display screen depending on the situation.

  If the display device is for ATM, when a customer using the ATM performs a deposit or withdrawal operation on the front of the display device, specifically the front of the display panel DSP, this customer is detected by a human sensor or the like. If detected, the viewing angle control panel VAC can limit the viewing angle of the display screen in response to the input signal from the human sensor. In other words, when there is no customer who uses ATM, the viewing angle of the display screen can be prevented from being limited.

  Next, a display device according to a second embodiment of the invention will be described with reference to the accompanying drawings. FIG. 7 schematically shows a cross-sectional structure of the display device. This display device is the same as that of the first embodiment except that the touch panel TP is placed on the viewing angle control panel VAC as a position coordinate input tool. For this reason, in FIG. 7, the same part as 1st Embodiment is represented by the same referential mark, and the overlapping description is abbreviate | omitted.

  The touch panel TP has a structure in which a pair of light transmissive substrates P1 and P2 are close to each other and face each other. The light transmissive substrates P1 and P2 have transparent insulating substrates 31 and 32, and first and second transparent conductive films 33 and 34 formed on the transparent insulating substrates 31 and 32, respectively. The transparent conductive films 33 and 34 are resistors such as ITO (Indium Tin Oxide) having a uniform resistance distribution. The transparent insulating substrates 31 and 32 are bonded to each other so that the transparent conductive films 33 and 34 are slightly spaced apart and overlapped by the peripheral sealing material SL disposed along the outer edge. The transparent insulating substrate 31 is attached to the polarizing plate 11 of the viewing angle control panel VAC. A space surrounded by the peripheral sealing material SL between the transparent insulating substrates 31 and 32 is filled with, for example, an inert gas 5b (or liquid). Further, in this space, the gap material 35 is sprayed in order to maintain the transparent conductive films 33 and 34 in a non-contact state except for a portion pressed by the pointer member 36 as shown in FIG. In the case of ATM, the pointer member 36 is substituted with a customer's fingertip. Here, the sheet resistance of the transparent conductive film 33 is about 10 ohms per unit area, and the sheet resistance of the transparent conductive film 34 is about 500 ohms per unit area.

  FIG. 9 shows a configuration of a position detection circuit using the touch panel TP shown in FIG. The transparent conductive films 33 and 34 each have a rectangular shape corresponding to the display screen of the display panel DSP. The striped electrode E0 is made of, for example, a conductive film formed by printing or a metal film such as silver. For example, the stripe-shaped electrode E0 extends along the side that is one end of the transparent conductive film 34 in the horizontal axis (X-axis) direction and is connected to this side to be transparent. It is formed on the insulating substrate 32. Here, a constant voltage source 37 such as a battery is connected to the electrode E0 on the transparent insulating substrate 32 side. In this case, the current flowing from the contact point of the transparent conductive films 33 and 34 to the transparent conductive film 32 changes depending on the transparent conductive films 33 and 34 and the wiring resistance of the peripheral circuit. The striped electrodes EX1 and EX2 are made of a metal film such as silver, and are along the two short sides, which are both ends of the transparent conductive film 33 in the horizontal axis (X-axis) direction, and are connected to these two short sides, respectively. 31 is formed. The striped electrodes EY1 and EY2 are made of a metal film such as silver, and are transparent along the two long sides which are both ends of the transparent conductive film 33 in the vertical axis (Y-axis) direction. It is formed on the insulating substrate 32. Two current detectors SA1, SA2, SA3, SA4 are provided for the electrodes EX1, EY1, EX2, EY2, respectively.

  The current detection unit SA1 measures a current Ix1 flowing through the transparent conductive film 33 from the contact point of the transparent conductive films 33 and 34 toward the electrode EX1, and the current detection unit SA2 is directed from the contact point of the transparent conductive films 33 and 34 to the electrode EY1. The current Iy1 flowing through the transparent conductive film 33 is measured, the current detection unit SA3 measures the current Ix2 flowing through the transparent conductive film 33 from the contact point of the transparent conductive films 33 and 34 toward the electrode EX2, and the current detection unit SA4 is transparent conductive. A current Iy2 flowing through the transparent conductive film 33 from the contact point of the films 33 and 34 toward the electrode EY2 is measured. The measured values of these currents Ix1, Iy1, Ix2, and Iy2 are supplied to the processor circuit 38 from the current detectors SA1 to SA4. The processor circuit 38 converts the measured values of the currents Ix1, Iy1, Ix2, and Iy2 into an arithmetic expression that defines the relationship between the X coordinates of the contacts with these four currents and an arithmetic expression that defines the relationship between these four currents and the Y coordinates of the contacts, respectively. By substituting and performing arithmetic processing, the X coordinate and Y coordinate of the contact points of the transparent conductive films 33 and 34 are obtained. Further, the processor circuit 38 turns on / off a signal indicating that one of the current detection units SA1 to SA4 has detected the current that flows when the transparent conductive films 33 and 34 are pressed by the pointer member 36 and come into contact therewith. The circuit 23 is supplied as an external control signal. Note that the peripheral circuits such as the processor circuit 38 and the current detection units SA1 to SA4 are arranged outside the peripheral sealing material SL in the touch panel TP. For example, when these peripheral circuits are arranged on the transparent insulating substrate 32, a peripheral circuit forming region is provided on the transparent insulating substrate 31 outside the peripheral sealing material SL.

  In this embodiment, a constant voltage source 37 such as a battery that outputs a voltage E2 is connected to the electrode E0 on the transparent insulating substrate 32 side. In this case, the current flowing from the contact point of the transparent conductive films 33 and 34 to the transparent conductive film 33 changes depending on the wiring resistance of the transparent conductive films 33 and 34 and the peripheral circuit, but flows from the contact point of the transparent conductive films 33 and 34. The currents are shunted to the currents Ix1, Iy1, Ix2, and Iy2 directed to the electrodes EX1, EY1, EX2, and EY2, respectively, corresponding to the resistance ratios in the X-axis and Y-axis directions. Therefore, the measured values of the currents Ix1, Iy1, Ix2, and Iy2 are respectively substituted into an arithmetic expression that defines the relationship between the X coordinates of the contacts with these four currents and an arithmetic expression that defines the relationship between these four currents and the Y coordinates of the contacts. Thus, the X and Y coordinates of the contact points of the transparent conductive films 33 and 34 can be obtained by performing the calculation process.

  If the display device is for ATM, the customer who uses the ATM is positioned in front of the display device, specifically, in front of the display panel DSP, and touches the touch panel TP while viewing the image displayed on the display panel DSP. It can be operated to deposit or withdraw cash. Furthermore, the viewing angle control panel VAC can limit the viewing angle of the display screen only when the processor circuit 38 detects that the operation of the touch panel TP has been started. In other words, when there is no customer who operates the touch panel TP, the viewing angle of the display screen can be prevented from being limited.

  FIG. 10 shows a modification of the display device shown in FIG. In this modification, the transparent insulating substrate 31 of the touch panel TP is attached to the transparent insulating substrate 9 in place of the polarizing plate 11 of the viewing angle control panel VAC, and the polarizing plate 11 is attached to the transparent insulating substrate 32 outside the touch panel TP. Attached.

  In this configuration, since the transparent insulating substrates 3 and 9 made of the same material are in contact with each other, a problem occurs when the polarizing plate 11 made of a material different from the substrates 3 and 9 is interposed between the substrates 3 and 9. It is possible to prevent a decrease in transmittance due to desired light reflection. From the viewpoint of preventing a decrease in transmittance, the touch panel TP and the viewing angle control panel VAC may be integrally configured using a common light-transmitting substrate that also serves as the transparent insulating substrates 3 and 9 described above.

  FIG. 11 shows a modification of the display device shown in FIG. This modification is applied when the display panel DSP is other than the liquid crystal display panel and does not have the polarizing plate 6 shown in FIG. In this case, the polarizing plate 39 is attached to the transparent insulating substrate 7 of the viewing angle control panel VAC. Thereby, for example, an organic EL panel or the like can be used as the display panel DSP.

  FIG. 12 shows a first modification of the viewing angle control panel 18 shown in FIG. In this modification, the controller 15 is configured to supply a vertical synchronization signal generated in the control of the display panel DSP to the clock generation circuit 21 as a timing signal for polarity inversion of the first and second electrodes EL1, EL2.

  FIG. 13 shows a second modification of the viewing angle control panel 18 shown in FIG. In this modification, a counter frequency dividing circuit 51 is further provided. The counter frequency dividing circuit 51 counts and divides the horizontal synchronization signal generated by the controller 15 in the control of the display panel DSP or the data transfer clock signal, thereby dividing the timing signal for polarity inversion of the first and second electrodes EL1, EL2. Is a timing circuit that generates and supplies the clock to the clock generation circuit 21.

  FIG. 14 shows a third modification of the viewing angle control panel 18 shown in FIG. In this modification, a frequency filter frequency dividing circuit 52 is further provided. The frequency filter frequency dividing circuit 52 divides the composite sync signal of the analog RGB video signal supplied to the controller 15 so as to filter the horizontal sync component while leaving the vertical sync component, so that the first and second electrodes EL1,1 and EL2 are divided. This is a timing circuit such as a mono multivibrator that generates a polarity inversion timing signal for EL2 and supplies it to the clock generation circuit 21.

  In the first to third modifications described above, it is possible to prevent display unevenness due to a shift in polarity inversion on the display panel DSP side and polarity inversion on the viewing angle control panel VSC side.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change variously further.

  The control unit CNT is preferably configured to operate with a DC power supply voltage obtained from at least one of a solar battery, a dry battery, and a power supply terminal of a computer such as a USB terminal.

  In addition, the control unit CNT is configured to include a switch control circuit that turns on the switch circuit 23 using a change in an input signal input from any of a touch panel TP, a human sensor, and an external switch provided additionally. May be.

  The switch control circuit may be configured to turn off the switch circuit 23 when it is not re-triggered within a certain time.

  The switch circuit 23 may be controlled by a switch control signal from the processor circuit 38 of the touch panel TP provided additionally.

  The switch circuit 23 may be controlled by a switch control signal input from the outside so as to maintain an on state and an off state that are set in advance based on an image displayed on the display panel.

  Further, the control unit CNT may be configured to include a switch control circuit that changes the state of the switch circuit 23 based on an input signal input from any of a touch panel, a voice microphone, and an external switch that are additionally provided. Good.

  Further, the viewing angle control panel VAC not only changes both the potentials of the first and second electrodes EL1 and EL2 as shown in FIG. 4 by periodic polarity inversion of the drive voltage, but also, for example, as shown in FIG. Alternatively, one potential of the first and second electrodes EL1, EL2 may be fixed as a reference potential, and the other potential may be changed with respect to the reference potential.

  In the above-described embodiment, the case where the touch panel TP is a current detection resistive film type that detects the currents Ix1, Iy1, Ix2, and Iy2 in order to obtain the X and Y coordinates of the contacts of the transparent conductive films 33 and 34 will be described. However, this touch panel TP may be any system such as a voltage detection resistance film system, an optical system, and a capacitance system as conventionally known.

It is a figure which shows roughly the cross-section of the display apparatus which concerns on one Embodiment of this invention. It is a figure which shows roughly the circuit structure of the display apparatus shown in FIG. FIG. 3 is a diagram illustrating an example of a circuit configuration of a viewing angle control panel driving circuit illustrated in FIG. 2. It is a wave form diagram which shows the electrical potential change of the 1st and 2nd electrode of the viewing angle control panel shown in FIG. It is a figure which shows the checker pattern which masks a display image about the direction inclined to the one side with respect to the front direction in the display apparatus shown in FIG. It is a figure which shows the checker pattern which masks a display image about the direction which inclined in the other side with respect to the front direction in the display apparatus shown in FIG. It is a figure which shows roughly the cross-section of the display apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the state by which the touch panel shown in FIG. 7 was pressurized by the pointer member. It is a figure which shows the structure of the position detection circuit using the touch panel shown in FIG. It is a figure which shows the modification of the display apparatus shown in FIG. It is a figure which shows the modification of the display apparatus shown in FIG. It is a figure which shows the 1st modification of the viewing angle control panel shown in FIG. It is a figure which shows the 2nd modification of the viewing angle control panel shown in FIG. It is a figure which shows the 3rd modification of the viewing angle control panel 18 shown in FIG. It is a figure which shows the electric potential of the 1st and 2nd electrode of the viewing angle control panel set to the relationship different from the relationship shown in FIG.

Explanation of symbols

  DSP ... display panel, VAC ... viewing angle control panel, TP ... touch panel, T1, T2 ... light transmissive substrate, LB ... liquid crystal layer, 6, 11 ... polarizing plate, EL1, EL2 ... first and second electrodes, 8, DESCRIPTION OF SYMBOLS 10 ... Orientation film, 18 ... Viewing angle control panel, 19 ... Switch control circuit, 21 ... Clock generation circuit, 22 ... Amplitude adjustment circuit, 23 ... Switch circuit.

Claims (18)

A viewing angle control panel that selectively restricts the viewing angle of a display screen, comprising: a pair of light transmissive substrates; a liquid crystal layer sandwiched between the pair of light transmissive substrates; and A first polarizing plate and a second polarizing plate disposed on the outside of the pair of light transmissive substrates, respectively, and the pair of light transmissive substrates are disposed on the pair of substrates so as to face each other, and an electric field is applied to the liquid crystal layer. And first and second alignment films that cover the first and second electrodes, respectively, adjacent to the liquid crystal layer, and the first and second alignment films are the first and second alignment films, respectively. And a liquid crystal that cooperates with the second polarizing plate to reduce the transmittance of light traveling from the front direction substantially perpendicular to the substrate surface to the direction inclined to one side when a voltage is applied between the first and second electrodes. A first alignment section defining the orientation direction of the molecule and the front It is composed of a combination with a second alignment portion that defines the alignment direction of liquid crystal molecules that reduces the light transmittance toward the direction inclined to the other side with respect to the front direction substantially perpendicular to the substrate surface when a voltage is applied. A characteristic viewing angle control panel. A display panel that displays an image on a display screen; and a viewing angle control panel that is arranged on the display panel and selectively restricts a viewing angle of an image displayed on the display panel. A light transmissive substrate, a liquid crystal layer sandwiched between the pair of light transmissive substrates, and first and second polarizing plates respectively disposed outside the pair of light transmissive substrates with respect to the liquid crystal layer. The first and second electrodes that are disposed on the pair of substrates so as to face each other and apply an electric field to the liquid crystal layer, and the liquid crystal layer adjacent to the liquid crystal layer. First and second alignment films covering the first and second electrodes, respectively, and the first and second alignment films cooperate with the first and second polarizing plates, and a voltage is applied between the first and second electrodes. Is almost perpendicular to the substrate surface when a voltage is applied. A first alignment section that aligns liquid crystal molecules in a direction that reduces the light transmittance toward a direction inclined from the front direction toward one side, and the other direction with respect to the front direction substantially perpendicular to the substrate surface when the voltage is applied. A display device comprising a combination with a second alignment portion that aligns liquid crystal molecules in a direction that decreases the transmittance of light directed toward a direction. The display device according to claim 2, wherein the display panel is a liquid crystal display panel having a polarizing plate that also serves as the first polarizing plate. The display device according to claim 2, wherein a touch panel is disposed as an input tool for position coordinates so as to overlap the viewing angle control panel. The display device according to claim 2, wherein the second polarizing plate is disposed outside the touch panel. The display device according to claim 2, further comprising a control circuit that controls the display panel and the viewing angle control panel. The control circuit applies a clock generation circuit for generating a clock signal serving as a polarity inversion timing for the first and second electrodes, and an amplitude of the clock signal obtained from the clock generation circuit between the first and second electrodes. The display device according to claim 6, further comprising an amplitude adjustment circuit that adjusts the drive voltage to be adjusted. The display device according to claim 7, wherein the control circuit further includes a switch circuit that selectively supplies the driving voltage obtained from the amplitude adjustment circuit to the viewing angle control panel. The control circuit is configured to supply a vertical synchronization signal generated in the control of the display panel to the clock generation circuit as a timing signal for polarity inversion of the first and second electrodes. 9. The display device according to 8. The control circuit generates the clock by generating a timing signal for polarity inversion of the first and second electrodes from any one of a horizontal synchronizing signal, a data transfer clock signal, and a composite synchronizing signal generated in controlling the display panel The display device according to claim 8, further comprising a timing circuit that supplies the circuit. The control circuit generates a polarity inversion timing signal for the first and second electrodes from one of a vertical synchronization signal and a horizontal synchronization signal supplied together with a video signal from the outside in the control of the display panel, and the clock generation circuit The display device according to claim 8, further comprising a timing circuit for supplying to the display. The display device according to claim 6, wherein the control circuit is configured to operate with a DC power supply voltage obtained from at least one of a solar battery, a dry battery, and a computer power supply terminal. The control circuit includes a switch control circuit that turns on the switch circuit triggered by a change in an input signal input from any one of a touch panel, a human sensor, and an external switch provided additionally. 9. The display device according to 8. 14. The display device according to claim 13, wherein the switch control circuit is configured to turn off the switch circuit when it is not re-triggered within a predetermined time. 9. The display device according to claim 8, wherein the switch circuit is controlled by a switch control signal from a position detection processor circuit of a touch panel additionally provided. 9. The switch circuit according to claim 8, wherein the switch circuit is controlled by a switch control signal input from the outside so as to maintain a preset ON state and OFF state based on an image displayed on the display panel. The display device described. The control circuit includes a switch control circuit that changes a state of the switch circuit based on an input signal input from any one of a touch panel, a voice microphone, and an external switch additionally provided. The display device described in 1. The display device according to claim 4, wherein the touch panel and the viewing angle control panel are integrally configured using a common light-transmitting substrate.

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