JP5305740B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device equipped with an input function.

  2. Description of the Related Art A touch panel-mounted liquid crystal display device is known that combines a touch panel (input device) that can input a predetermined signal corresponding to a touched position when the liquid crystal display screen is touched with a finger or a touch pen. In a device provided with such a liquid crystal display device with a touch panel, the operation of the device, the selection of the function, and the like can be performed by touching the screen (touch panel), and thus the operation of the device is facilitated. For this reason, the above-mentioned liquid crystal display device with a touch panel is widely used in information devices such as a car navigation system and a portable information terminal.

  Conventionally, a resistance film method or the like is generally known as a coordinate detection method of a touch panel. This resistive film type touch panel is relatively low cost and can be externally input only by being mounted on the surface of a liquid crystal display screen. Such a resistive film type touch panel liquid crystal display device is described in Patent Document 1, for example.

  However, a liquid crystal display device equipped with a touch panel such as the above-described resistive film method has a disadvantage in that display quality is deteriorated because the reflection of external light occurs or the transmittance of display light decreases when the touch panel is bonded. It was. Moreover, since it is necessary to attach a touch panel separately on a liquid crystal display screen, there also existed a problem that it was difficult to achieve thickness reduction of a liquid crystal display device.

Therefore, conventionally, a liquid crystal display device in which a liquid crystal display panel incorporates a touch panel function (input function) by incorporating an optical sensor element in each pixel of the liquid crystal display panel is known. In this liquid crystal display device, light reflected from an object to be detected such as a finger or a touch pen by external light such as sunlight or light of a video signal emitted from the liquid crystal display panel is detected by a photosensor element built in the pixel. Then, coordinate detection (position detection) is performed by a detection signal from the optical sensor element. As described above, in the conventional liquid crystal display device with the built-in photosensor element, it is not necessary to attach a separate touch panel on the liquid crystal display screen. be able to.
JP 2003-162375 A

  However, in the above-described conventional liquid crystal display device incorporating a photosensor element, when the light sensor element detects light reflected from a detection object by external light such as sunlight, the touch panel function is provided in a dark environment. There is a problem that it becomes difficult to use. On the other hand, when the light reflected from the object to be detected by the light of the video signal emitted from the liquid crystal display panel is detected by the optical sensor element, the touch panel function can be used even in a dark environment. There is an inconvenience that the emitted light needs to be made quite strong. As a result, it is difficult to use a dark design for the design of the display image.

  The present invention has been made in order to solve the above-described problems, and one object of the present invention is to reduce the display quality while suppressing a decrease in display quality, and to provide a dark environment. However, an object is to provide a liquid crystal display device that can use the input function and is not restricted by the design of the display image.

  In order to achieve the above object, a liquid crystal display device according to an aspect of the present invention includes a liquid crystal display panel including a pixel region in which a plurality of pixels are two-dimensionally arranged, and facing one main surface of the liquid crystal display panel. And an illumination unit that irradiates the pixel region of the liquid crystal display panel. In the pixel region of the liquid crystal display panel, a plurality of wavelength conversions that convert visible light from the illumination unit into invisible light and emit the converted invisible light to the other main surface side opposite to the main surface. An element and a plurality of optical sensor elements that detect invisible light wavelength-converted by the wavelength conversion element are formed.

  In the liquid crystal display device according to this one aspect, as described above, in the pixel region of the liquid crystal display panel, visible light from the illumination unit is converted into invisible light, and the converted invisible light is on the side opposite to one main surface. By forming a plurality of wavelength conversion elements that emit to the other main surface side, invisible light can be emitted from the plurality of wavelength conversion elements in the pixel region of the liquid crystal display panel. In addition, by forming a plurality of photosensor elements that detect invisible light in the pixel area of the liquid crystal display panel, light reflected from a detection object such as a finger by invisible light emitted from the pixel area (invisible light) Can be detected by the optical sensor element. Therefore, since coordinate detection (position detection) can be performed based on the detection signal detected by the optical sensor element, coordinate detection (position detection) can be performed without using outside light such as the sun. As a result, the input function can be used even in a dark environment.

  In the liquid crystal display device according to one aspect, the light used for coordinate detection (position detection) is invisible light emitted from the wavelength conversion element, so that the user does not perceive the presence or absence of the light emission. For this reason, no matter how invisible light is emitted (emitted), the display image (display image) displayed on the display screen is not affected. Thus, unlike coordinate detection (position detection) using the light of the video signal emitted from the liquid crystal display panel, the display image (display video) picture creation is devised to perform coordinate detection (position detection). Therefore, coordinate detection (position detection) can be performed without being restricted by the design of the display image (display video).

  In the configuration described above, the liquid crystal display panel can have an input function (touch panel function) by forming the wavelength conversion element and the optical sensor element in the pixel region. For this reason, there is no need to attach an input device such as a touch panel on the display screen, and accordingly, the liquid crystal display device can be made thinner. In addition, it is possible to suppress a decrease in display quality caused by attaching the input device.

  In the liquid crystal display device according to the above aspect, the invisible light converted by the wavelength conversion element is preferably infrared light, and the photosensor element is an infrared light receiving element that detects infrared light. If comprised in this way, since infrared light reflects on the surface of many substances, it can reflect efficiently with to-be-detected bodies, such as a finger | toe which approached the display screen. For this reason, coordinate detection (position detection) can be performed with high accuracy by receiving the reflected light from the detection object by the infrared light receiving element. Moreover, since infrared light does not damage a substance, it can be suitably used as invisible light.

  In the liquid crystal display device according to the one aspect described above, preferably, the wavelength changing element has a multilayer structure in which a red filter layer and a near-infrared phosphor layer are formed from the illumination unit side. It has the function of transmitting the red light wavelength component in the visible light from the illumination unit, and the near-infrared phosphor layer has the function of converting the red light transmitted through the red filter layer into near-infrared light. ing. If comprised in this way, while being able to convert easily the visible light irradiated from the illumination part into the near-infrared light which is invisible light, it is easy to convert the converted near-infrared light of a liquid crystal display panel. The light can be emitted from the pixel region to the other main surface.

  In the liquid crystal display device according to the above aspect, preferably, the plurality of wavelength conversion elements are two-dimensionally arranged at a predetermined interval in the pixel region, and the plurality of photosensor elements are two-dimensionally arranged. The pixel regions are two-dimensionally arranged at a predetermined interval so as to correspond to the wavelength conversion elements. With this configuration, it is possible to use the input function even in a dark environment, and the detection accuracy of coordinate detection (position detection) is improved in addition to not being restricted by the design of the display image. be able to.

  In the liquid crystal display device according to the above aspect, the plurality of wavelength conversion elements are preferably arranged in the vicinity of the corresponding optical sensor elements. If comprised in this way, the detection accuracy of coordinate detection (position detection) can be improved more.

  The liquid crystal display device according to the above aspect may be configured such that at least some of the plurality of pixels include a wavelength conversion element and an optical sensor element.

  In this case, preferably, each of the plurality of pixels includes a wavelength conversion element and an optical sensor element. With this configuration, invisible light can be emitted from each of the pixels, and reflected light from the detection target can be detected at each of the pixels, so that coordinate detection (position detection) can be detected. The accuracy can be further improved.

  In the liquid crystal display device according to the above aspect, the liquid crystal display panel includes a first substrate and a second substrate that is disposed closer to the illumination unit than the first substrate and faces the first substrate with a predetermined interval therebetween. And a liquid crystal layer sandwiched between the first substrate and the second substrate. On the main surface of the second substrate on the first substrate side, a plurality of pixel electrodes are formed. Preferably, a counter electrode facing the pixel electrode is formed on the main surface of the second substrate side.

  In the configuration including the pixel electrode and the counter electrode, the wavelength conversion element is preferably formed on the main surface of the first substrate on the second substrate side and between the first substrate and the counter electrode. In addition, when a voltage is applied between the pixel electrode and the counter electrode, invisible light is emitted from the wavelength conversion element to the other main surface side of the liquid crystal display panel at a predetermined period. When the detection signal detected by the optical sensor element coincides with the predetermined period, the position information of the detected object is acquired. If comprised in this way, even when invisible light injects into the pixel area of a liquid crystal display panel from the outside, the positional information on a to-be-detected body can be detected correctly.

  In this case, the liquid crystal display panel is preferably configured to be able to emit invisible light from the plurality of wavelength conversion elements at different periods. With this configuration, when the detection signal detected by the optical sensor element matches the period of the invisible light emitted from the wavelength conversion element corresponding to the optical sensor element, the position information of the detection target is acquired. Can be configured. And by configuring in this way, for example, when invisible light hits a metal accessory such as a ring or a bracelet, and the reflected light reflected by the metal accessory or the like is detected by an optical sensor element at an unexpected position However, it can be determined that the detection signal detected by the optical sensor element is not due to invisible light emitted from the corresponding wavelength conversion element. Accordingly, it is possible to suppress the inconvenience of erroneous input due to reflected light from a metal accessory or the like. As a result, the position information of the detection target can be detected with higher accuracy.

  In the liquid crystal display device according to the above aspect, the liquid crystal display panel further includes a color filter including a plurality of types of filter layers that transmit light in different wavelength regions, and the pixels of the liquid crystal display panel are configured as color pixels by the color filter. May be.

  In this case, the color filter can be configured to include at least three types of filter layers of red, blue, and green.

  In the configuration in which the wavelength conversion element and the optical sensor element are provided in the pixel, it is preferable that the wavelength conversion element and the optical sensor element are arranged close to each other.

  As described above, according to the present invention, it is possible to reduce the thickness while suppressing deterioration in display quality, it is possible to use the input function even in a dark environment, and A liquid crystal display device free from design restrictions can be easily obtained.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating a configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 2 is a plan view illustrating a pixel configuration of a liquid crystal display device according to an embodiment of the present invention. FIG. 3 is a block diagram of a liquid crystal display device according to an embodiment of the present invention. 4 to 10 are views for explaining the structure of a liquid crystal display device according to an embodiment of the present invention. First, a structure of a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the liquid crystal display device according to one embodiment is configured as a transmissive liquid crystal display device, and includes a backlight unit 10 and a liquid crystal display panel 20. The backlight unit 10 is an example of the “illumination unit” in the present invention.

  As shown in FIG. 3, the liquid crystal display device according to the embodiment includes a control unit 60, a pixel drive circuit unit 70, a photosensor element drive circuit unit 80, a backlight drive circuit unit 90, and a power supply circuit unit. 100, an image signal input interface 110, and an external system interface 120.

  The backlight unit 10 includes a light source (not shown) such as an LED (Light Emitting Diode), and a light guide plate (not shown) that converts light from the light source into planar light. As shown in FIG. 1, white light (visible light) is emitted from the light emitting surface 10a. The backlight unit 10 is arranged on the back surface (one main surface) side of the liquid crystal display panel 20. That is, the liquid crystal display panel 20 is arranged above the light emission surface 10a of the backlight unit 10 so that the back surface (one main surface) of the liquid crystal display panel 20 and the light emission surface 10a of the backlight unit 10 face each other. ing.

  As shown in FIG. 4, the liquid crystal display panel 20 includes a display area (pixel area) 20a for displaying an image, and the liquid crystal display panel 20 is provided by the backlight unit 10 (see FIG. 1) arranged on the back side. White light (visible light) is irradiated on the entire surface of the display area 20a from the back side of the display. In the display area 20a, as shown in FIG. 2, a plurality of pixels 21 are arranged in a two-dimensional matrix. Each of the plurality of pixels 21 is configured as a color pixel by a color filter 43 described later. Specifically, each of the plurality of pixels 21 includes three sub-pixels 21R, 21G, and 21B of red (R), green (G), and blue (B), which are the three primary colors of light.

  Here, in the present embodiment, each of the plurality of pixels 21 receives the near-infrared element 22 that emits near-infrared light and the near-infrared light in addition to the three sub-pixels 21R, 21G, and 21B. And an optical sensor element 23 composed of a near-infrared light receiving element. As shown in FIG. 1, the near-infrared element 22 converts visible light (white light) emitted from the backlight unit 10 into near-infrared light that is invisible light, and the converted near-infrared light is displayed on a liquid crystal display. It has a function of sending (emitting) from the display area 20a (see FIG. 4) of the panel 20 to the front (one main surface) side. Further, the optical sensor element 23 detects light reflected by a detection target (such as a finger) by invisible light (near infrared light) emitted from the near infrared element 22. The near-infrared element 22 and the optical sensor element 23 are arranged close to each other in the same pixel. The near-infrared element 22 is an example of the “wavelength conversion element” in the present invention.

  The liquid crystal display panel 20 has an active matrix structure. Specifically, the liquid crystal display panel 20 includes an array substrate 30 and a counter substrate 40 as shown in FIGS. The array substrate 30 and the counter substrate 40 are arranged to face each other with a predetermined interval by a plurality of spacers (not shown). The array substrate 30 and the counter substrate 40 are bonded to each other by a sealing material (not shown) disposed at the peripheral edge of both substrates. Further, as shown in FIG. 1, a liquid crystal layer 50 is sandwiched between the array substrate 30 and the counter substrate 40 by the array substrate 30, the counter substrate 40, and a sealing material (not shown). The liquid crystal layer 50 is made of, for example, TN (Twisted Nematic) liquid crystal.

  The array substrate 30 includes a glass substrate 31 that is an insulating substrate that transmits light. On the upper surface of the glass substrate 31 (on the main surface on the counter substrate 40 side), a plurality of thin film transistors (TFTs) 32 (see FIG. 6) functioning as switching elements are formed in an array. A plurality of pixel electrodes 33 are formed on the upper surface of the glass substrate 31, as shown in FIGS. Each of these pixel electrodes 33 is formed in a substantially rectangular shape extending in the Y direction when seen in a plan view. Each of the plurality of pixel electrodes 33 is connected to the drain electrode of the TFT 32.

  In the present embodiment, each pixel 21 includes four pixel electrodes 33. Of the four pixel electrodes 33, three pixel electrodes 33a are provided to drive the three sub-pixels 21R, 21G, and 21B of red (R), green (G), and blue (B), respectively. . The remaining pixel electrode 33 b is provided for driving the near infrared element 22.

  In addition, a plurality of scanning lines 34 (see FIG. 6) extending in the horizontal direction (X direction) are formed on the upper surface of the glass substrate 31 so as to be aligned in the vertical direction (Y direction). A plurality of signal lines 35 (see FIG. 6) extending in the direction (Y direction) are formed to be aligned in the horizontal direction (X direction). The TFT 32 described above is arranged at each position where the scanning line 34 and the signal line 35 intersect. As shown in FIG. 6, the gate electrode of the TFT 32 is connected to the scanning line 34, and the source electrode of the TFT 32 is connected to the signal line 35.

  As shown in FIG. 1, the counter substrate 40 includes a glass substrate 41, which is an insulating substrate that transmits light, like the array substrate 30. On the upper surface of the glass substrate 41 (on the main surface on the array substrate 30 side), a counter electrode 42 facing the pixel electrode 33 is formed. The counter electrode 42 is one electrode common to all pixels on the glass substrate 41. The pixel electrode 33 and the counter electrode 42 described above are each formed of a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). The glass substrates 41 and 31 are examples of the “first substrate” and the “second substrate” in the present invention, respectively.

  Further, between the liquid crystal layer 50 and the pixel electrode 33 and between the liquid crystal layer 50 and the counter electrode 42, an alignment film 24 (24 a and 24 b) for controlling the alignment of the liquid crystal molecules constituting the liquid crystal layer 50. ) Are respectively formed. The alignment film 24 is made of, for example, a polyimide resin and is subjected to an alignment process (for example, a rubbing process).

  Further, the color filter 43 described above is provided between the glass substrate 41 and the counter electrode 42 on the main surface of the glass substrate 41 (counter substrate 40) on the array substrate 30 (glass substrate 31) side. Yes. The color filter 43 includes a plurality of types of filter layers that transmit light in different wavelength regions. Specifically, the color filter 43 includes three types of filter layers: a red filter layer 43R, a green filter layer 43G, and a blue filter layer 43B. As shown in FIG. 2, each of these filter layers has a substantially rectangular shape extending in the Y direction when seen in a plan view. As shown in FIG. 1, the filter layers correspond to the corresponding pixel electrodes 33 (33a). It is formed so as to face each other. The color filter 43 is formed using, for example, a polyimide resin containing a colorant such as a pigment or a dye. Further, the gap between the filter layers is colored black so as not to transmit light. That is, a light shielding layer 44 in which a large number of black bands are arranged in a matrix is formed in the gap between the filter layers.

  One pixel of the liquid crystal display panel 20 includes three filter layers, a red filter layer 43R, a green filter layer 43G, and a blue filter layer 43B.

  Here, in this embodiment, as shown in FIGS. 1 and 2, the glass substrate 41 and the counter electrode are on the main surface of the glass substrate 41 (counter substrate 40) on the array substrate 30 (glass substrate 31) side. The near-infrared element 22 is provided between the color filter 43 and the color filter 43. As shown in FIG. 2, the near-infrared element 22 has a substantially rectangular shape extending in the Y direction when viewed in plan, like the filter layer, and faces the pixel electrode 33 (33b). Further, it is formed on the glass substrate 41. The near-infrared element 22 is disposed between the blue filter layer 43B and the red filter layer 43R of the adjacent pixel 21. Further, the near-infrared element 22 has a multilayer structure (two-layer structure) in which a red filter layer 22a and a near-infrared phosphor layer 22b are sequentially formed from the backlight unit 10 side. The red filter layer 22a has a function of transmitting only the wavelength component of red light among the white light (visible light) emitted from the backlight unit 10. The near infrared phosphor layer 22b has a function of converting red light transmitted through the red filter layer 22a into near infrared light.

  Further, in the present embodiment, as shown in FIGS. 5 and 7, the plurality of photosensor elements 23 described above are formed in a matrix on the upper surface of the array substrate 30 (glass substrate 31). The optical sensor element 23 is formed in a substantially rectangular shape extending in the X direction when seen in a plan view. Further, on the upper surface of the glass substrate 31, as shown in FIG. 7, a plurality of drive electrodes 25-1 to 25-m for applying a voltage for driving the photosensor element 23 and a plurality of drive electrodes 26 are applied. -1 to 26-n and an output electrode 27 for outputting a detection signal (sensor signal) from the optical sensor element 23 are formed. The drive electrodes 25-1 to 25-m extend in the vertical direction (Y direction) and are arranged in the horizontal direction (X direction). The drive electrodes 26-1 to 26-n are arranged in the horizontal direction ( It extends in the (X direction) and is aligned in the vertical direction (Y direction). In the counter substrate 40, the region facing the optical sensor element 23 is in a state where the color filter 43 and the near infrared element 22 are not formed.

  A plurality of storage capacitors 28 (see FIG. 6) are formed on the upper surface of the glass substrate 31 (array substrate 30) on which the TFTs 32 are formed. One electrode of the storage capacitor 28 is connected to the drain electrode of the TFT 32 as shown in FIG. Therefore, the storage capacitor 28 is a load of the TFT 32 in parallel with the liquid crystal capacitor 29 formed by the pixel electrode 33 and the counter electrode 42 facing each other with the liquid crystal layer 50 interposed therebetween.

  As shown in FIG. 1, a linearly polarizing plate 51 is disposed on the outer surface side of the array substrate 30, and a linearly polarizing plate 52 is disposed on the outer surface side of the counter substrate 40. The linearly polarizing plate 51 and the linearly polarizing plate 52 are arranged such that their polarization axes are 90 °.

  The pixel drive circuit unit 70 includes a scanning circuit unit 71 and a signal circuit unit 72, and is disposed in a peripheral region of the liquid crystal display panel 20, as shown in FIG. The pixel drive circuit unit 70 has a function of driving the pixel 21 having the coordinates designated by the control unit 60. Further, as shown in FIG. 6, one end of the scanning line 34 is connected to the scanning circuit unit 71, and one end of the signal line 35 is connected to the signal circuit unit 72.

  As shown in FIG. 4, the optical sensor element drive circuit unit 80 includes a horizontal drive circuit unit 81 and a vertical drive circuit unit 82, and is a liquid crystal different from the region where the pixel drive circuit unit 70 is disposed. The display panel 20 is arranged in a peripheral area. One end of drive electrodes 25-1 to 25-m is connected to the horizontal drive circuit unit 81, and one end of drive electrodes 26-1 to 26-n is connected to the vertical drive circuit unit 82. Yes.

  The photosensor element 23 is composed of a phototransistor as shown in FIG. The collector of the phototransistor is connected to the vertical drive circuit unit 82 (see FIG. 9) via the drive electrode 26, while the emitter of the phototransistor is connected to the horizontal drive circuit via the resistor R and the drive electrode 25. It is connected to the part 81 (see FIG. 9). An output electrode 27 for outputting a sensor signal is connected between the emitter and the resistor R. If the output level of the sensor signal is weak, an amplifier circuit or the like may be added after the output electrode 27 to amplify the output level of the sensor signal. As shown in FIG. 9, the optical sensor element drive circuit unit 80 drives the optical sensor element 23 at the coordinates specified by the control unit 60 and sends the sensor signal of the optical sensor element 23 to the control unit 60. It has a function.

  The control unit 60 converts an image signal input from the outside via the image signal input interface 110 (see FIG. 3) into R (red), G (green), and B (blue), and the contents of the image signal. Then, after determining the coordinates of the pixel to be driven and the signal level of each sub-pixel, the converted image signal is output to the pixel drive circuit unit 70. The control unit 60 also outputs a drive signal for the near infrared element 22 to the pixel drive circuit unit 70. That is, the near-infrared element 22 is driven by the control unit 60 in a predetermined pattern (predetermined cycle) independently of driving of the pixels 21 (sub-pixels 21R, 21G, and 21B).

  Further, as shown in FIG. 9, the control unit 60 outputs a coordinate designation signal of the optical sensor element 23 to the optical sensor element drive circuit unit 80, and a sensor signal (optical sensor) from the optical sensor element 23 of the designated coordinate. Read the state of the element 23). Further, as shown in FIGS. 3 and 9, the control unit 60 includes a memory unit 61 that stores a sensor signal from the optical sensor element 23. In the memory unit 61, as shown in FIG. A predetermined number (for example, six times) of sensor signals output from the optical sensor element 23 are stored every predetermined time.

  As shown in FIG. 3, the backlight drive circuit unit 90 has functions of controlling the lighting and extinguishing of the backlight unit 10 according to instructions from the control unit 60 and adjusting the brightness. The power supply circuit unit 100 generates output power required from input power and supplies power to each unit.

  FIG. 11 is a schematic view for explaining the operation of the liquid crystal display device according to the embodiment of the present invention. 12 and 13 are timing charts showing driving signals for driving the optical sensor elements of the liquid crystal display device according to the embodiment of the present invention. Next, the operation of the liquid crystal display device according to the embodiment of the present invention will be described with reference to FIGS. 1, 3, 4 and 6 to 13. In the following description, the pixel array of the liquid crystal display device is described as an m × n pixel array.

  First, as shown in FIG. 3, the backlight unit 10 is turned on via the backlight drive circuit unit 90 according to an instruction from the control unit 60. Thereby, as shown in FIG. 11, white light (visible light) is emitted from the light emission surface 10 a of the backlight unit 10. When the emitted white light passes through the linearly polarizing plate 51, only light having an angle parallel to the polarization angle is transmitted. That is, by passing through the linearly polarizing plate 51, only the linearly polarized component of the white light emitted from the backlight unit 10 is transmitted, and the transmitted linearly polarized light A is incident on the liquid crystal layer 50.

  On the other hand, as shown in FIG. 3, when an image signal is input from the outside to the control unit 60 via the image signal input interface 110, the input image signal is R (red), G ( Green) and B (blue), and after determining the coordinates of the pixel to be driven and the signal level of each sub-pixel based on the content of the image signal, the converted image signal is converted into the pixel drive circuit unit 70. Is output.

  When an image signal is output to the pixel driving circuit unit 70, as shown in FIG. 6, a scanning voltage is sequentially supplied from the scanning circuit unit 71 of the pixel driving circuit unit 70 to the scanning line 34, and scanning in which the pulse voltage is supplied. All of the TFTs 32 connected to the line 34 are turned on. At this time, when a signal voltage based on an image signal is applied to the signal line 35 from the control unit 60 (see FIG. 3) via the signal circuit unit 72 of the pixel drive circuit unit 70, the drain electrode of the TFT 32 Then, charges are injected into the pixel electrode 33 (see FIG. 1) of the liquid crystal capacitor 29 connected thereto. Then, the electrode potential becomes the same level as the potential (signal voltage) of the signal line 35, and a potential difference is generated between the pixel electrode 33 (see FIG. 1) and the counter electrode 42 (see FIG. 1). This potential difference changes the alignment of the liquid crystal. Note that the other electrode of the storage capacitor 28 is connected to the scanning line 34 scanned one time before, and the TFT 32 is turned on at the next pulse voltage by the storage capacitor 28 and a signal voltage is applied. Until then, the potential of the pixel electrode 33 is maintained.

  Since the liquid crystal in which the orientation has been changed exhibits the characteristic of bending the polarization axis of linearly polarized light by 90 °, as shown in FIG. 11, the linearly polarized light A transmitted through the portion in which the orientation has changed in the liquid crystal layer 50 has a polarization axis of 90. The light is bent and incident on the color filter 43 and the near-infrared element 22. On the other hand, when there is no potential difference between the pixel electrode 33 and the counter electrode 42, the alignment of the liquid crystal does not change. For this reason, the linearly polarized light A that passes through the portion of the liquid crystal layer 50 where the alignment does not change passes through the liquid crystal layer 50 with the polarization angle controlled by the linear polarizing plate 51. The transmitted linearly polarized light A is incident on the color filter 43 and the near-infrared element 22. In FIG. 11, the linearly polarized light B whose polarization axis is bent is indicated by hatched arrows.

  When the linearly polarized light incident on the color filter 43 passes through each filter layer, only light of a specific wavelength component is transmitted and emitted to the linearly polarizing plate 52 side as red light, green light, or blue light. Is done. On the other hand, for the linearly polarized light incident on the near-infrared element 22, only the red light wavelength component of the white light (visible light) is first transmitted by the red filter layer 22a. Next, the red light transmitted through the red filter layer 22a is converted into near-infrared light which is invisible light by the near-infrared phosphor layer 22b and emitted to the linearly polarizing plate 52 side.

  Here, since the polarization axis of the linearly polarizing plate 52 is shifted by 90 ° with respect to the linearly polarizing plate 51, only the linearly polarized light B whose polarization axis is bent by 90 ° by the liquid crystal layer 50 is transmitted through the linearly polarizing plate 52. And visualized. As a result, by controlling the potential difference between each pixel electrode 33 (see FIG. 1) and the counter electrode 42 (see FIG. 1), the color pixel can emit light. The based image can be displayed on the display area 20a (see FIG. 4) of the liquid crystal display panel 20.

  Further, by controlling the potential difference between the pixel electrode 33 and the counter electrode 42, the front surface (see FIG. 4) of the display area 20a (see FIG. 4) of the liquid crystal display panel 20 in a predetermined pattern (period) independent of the image signal. Near infrared light (invisible light) can be emitted to the other main surface) side. The driving of the near-infrared element 22 can be controlled independently of the image display sub-pixels 21R, 21G, and 21B, and therefore has no effect on the display image displayed on the liquid crystal display panel 20. Not give.

  Then, as described above, the near-infrared light is emitted from the display area 20a (see FIG. 4) of the liquid crystal display panel 20, and the display screen of the liquid crystal display panel 20 is touched with a detection object such as a finger 200. The near-infrared light is reflected by the detection object, and the reflected light B1 is detected (received) by the optical sensor element 23. The detected signal is converted into a sensor signal of a logic level (Low (hereinafter, L) or High (hereinafter, H): light is received at H), and is sent to the controller 60 as shown in FIG.

  Reading the sensor signal from the optical sensor element 23 supplies the drive electrode 26 with an H level drive signal Y (applies a positive voltage) and supplies the drive electrode 25 with an L level drive signal X (GND level). To the state of For example, when reading the sensor signal of the optical sensor element 23 at the coordinates (p, q), as shown in FIG. 12, an H level drive signal Y (q) is supplied to the drive electrode 26-q to drive it. An L-level drive signal X (p) is supplied to the electrode 25-p. In this way, the optical sensor element 23 at the coordinates (p, q) is in the active state, so that the sensor signal can be sent to the control unit 60 via the output electrode 27 as shown in FIG. .

  The sensor signal from the optical sensor element 23 sent to the control unit 60 is stored in the optical sensor element input table (see FIG. 10) of the memory unit 61. Thereafter, as shown in FIG. 10, a reading process is performed a predetermined number of times (for example, six times) for the same coordinate at a predetermined interval (for example, 0.1 second). Then, if it is confirmed that the read data of the specific coordinate matches the drive pattern of the near infrared element 22, it is determined that the detected object is close to the specific coordinate. For example, when the output level (drive pattern) of the near-infrared element 22 is “L, H, L, H, H, L”, the coordinates (p, Since the read data of q) is “L, H, L, H, H, L” and matches the output level (driving pattern) of the near-infrared element 22, it is detected at the coordinates (p, q). It is judged that there is a proximity of the body.

  For example, in the coordinates (m, 1), coordinates (1, 2), coordinates (2, 2), and coordinates (m, n), the read data is “L, L, L, L, L, L”. Therefore, in the optical sensor element 23 of these coordinates, near infrared light is not detected, and it is determined that there is no proximity of the detected object. Further, for example, at the coordinates (m, 2) and the coordinates (1, 3), the read data is “H, H, H, L, H, H”. However, since it does not coincide with the output level (drive pattern) of the near-infrared element 22, it is determined that the noise is external light or the like. For this reason, it is determined that there is no proximity of the detected object at this coordinate. Further, for example, at the coordinates (1, 1) and the coordinates (2, 1), the read data is “H, H, H, H, H, H”, and in this case as well, the output of the near-infrared element 22 Does not match the level (drive pattern). In this case, since near-infrared light is always detected, it is determined that it is affected by near-infrared light due to external light such as sunlight. For this reason, it is determined that there is no proximity of the detected object even at this coordinate. Therefore, with the above configuration, even when near-infrared light from outside light such as sunlight is mixed, the position (coordinates) touched by the detection target can be accurately detected. That is, it is possible to suppress the occurrence of malfunction.

  When it is determined that there is an approaching object at a predetermined coordinate, the control unit 60 determines that the touch panel (a predetermined position on the display screen) has been pressed. When it is determined that the touch panel is pressed, the control unit 60 sends a press detection signal (detection detection signal) and its coordinates (detection coordinates) to the external system interface 120 (see FIG. 3). Thereby, the position (coordinates) with which the detection target such as the finger 200 comes into contact is detected based on the light detected by the optical sensor element 23 of the liquid crystal display panel 20.

  The data stored in the sensor signal input table shown in FIG. 10 is shifted to the right one by one when the next reading is performed, and the read data is stored in the “current” column.

  Further, the output level (drive pattern) of the near-infrared element 22 may be the same pattern (cycle) for all of the plurality of near-infrared elements 22 or may be a different pattern (cycle). Thus, if it is configured to have different patterns (periods), for example, near-infrared light (invisible light) emitted to metal accessories such as rings and bracelets hits and is reflected by metal accessories etc. Even when light is detected by the optical sensor element 23 at an unexpected position (coordinates), the sensor signal detected by the optical sensor element 23 is a near-infrared light emitted from the corresponding near-infrared element 22 ( It can be determined that it is not caused by invisible light. Accordingly, it is possible to suppress the inconvenience of erroneous input due to reflected light from a metal accessory or the like. As a result, the position information of the detection target can be detected with higher accuracy.

  Also, when using the touch panel function (input function), the position (coordinates) to be touched is often determined in advance, so it may be sufficient to determine whether or not the position (coordinates) has been touched (detected). Many. In such a case, by outputting a coordinate designation signal from the control unit 60 to the optical sensor element drive circuit unit 80, only the optical sensor element 23 having the designated coordinates is driven, and the sensor from the optical sensor element 23 is driven. You may make it read a signal.

  On the other hand, when reading sensor signals from all the optical sensor elements 23, it can be performed as follows. That is, as shown in FIG. 13, an H level drive signal Y (1) is supplied to the drive electrode 26-1 (see FIG. 7) (a positive voltage is applied), and the drive electrodes 25-1 to 25-m (FIG. 7), L level drive signals X (1) to X (m) are sequentially supplied. As a result, the optical sensor elements 23 at coordinates (1, 1) to coordinates (m, 1) are sequentially activated, and sensor signals from coordinates (1, 1) to coordinates (m, 1) are sequentially read. Next, as shown in FIG. 13, an H level drive signal Y (2) is supplied to the drive electrode 26-2 (a positive voltage is applied), and an L level drive is applied to the drive electrodes 25-1 to 25-m. Signals X (1) to X (m) are sequentially supplied. Thereby, the sensor signals from the coordinates (1, 2) to the coordinates (m, 2) are sequentially read. By repeating such an operation up to the drive electrode 26-n, sensor signals from the optical sensor element 23 at all coordinates (coordinates (1, 1) to coordinates (m, n)) are read.

  In the liquid crystal display device according to the present embodiment, as described above, white light (visible light) from the backlight unit 10 is converted into near-infrared light (invisible light) in the display region (pixel region) 20a of the liquid crystal display panel 20. A plurality of near infrared elements 22 in the display region 20a of the liquid crystal display panel 20 are formed by forming a plurality of near infrared elements 22 that convert and emit the converted near infrared light to the front side of the liquid crystal display panel 20. Can emit near-infrared light. Further, by forming a plurality of optical sensor elements 23 for detecting near-infrared light in the display area 20a of the liquid crystal display panel 20, the near-infrared light emitted from the display area 20a is used to detect a finger or the like. The reflected light (near infrared light) can be detected by the optical sensor element 23. And since coordinate detection (position detection) can be performed by the sensor signal from the optical sensor element 23, coordinate detection (position detection) can be performed without using outside light such as the sun. As a result, the input function (touch panel function) can be used even in a dark environment.

  In the present embodiment, since the light used for coordinate detection (position detection) is invisible light (near infrared light) emitted from the near infrared element 22, the user perceives the presence or absence of the light emission. There is no. Therefore, no matter how near-infrared light is emitted (emitted), the display image (display image) displayed on the display screen (display region 20a) is not affected. Thus, unlike the case where coordinate detection (position detection) is performed using the light of the video signal output from the liquid crystal display panel 20, a picture of a display image (display video) is created in order to perform coordinate detection (position detection). Since there is no need to devise, coordinate detection (position detection) can be performed without being restricted by the design of the display image (display video).

  In the above-described configuration, the liquid crystal display panel 20 (liquid crystal display device) can have an input function (touch panel function) by forming the near infrared element 22 and the optical sensor element 23 in the display region 20a. . For this reason, there is no need to attach an input device such as a touch panel on the display screen, and accordingly, the liquid crystal display device can be made thinner. In addition, it is possible to suppress a decrease in display quality caused by attaching the input device.

  In this embodiment, the near-infrared element 22 is configured in a multilayer structure in which the red filter layer 22a and the near-infrared phosphor layer 22b are formed from the backlight unit 10 side, so that the backlight can be easily obtained. The white light (visible light) emitted from the unit 10 can be converted into near-infrared light which is invisible light, and the converted near-infrared light can be easily converted from the display area 20a of the liquid crystal display panel 20 to the front. Can be emitted to the side.

  Further, in the present embodiment, by forming the near-infrared element 22 and the optical sensor element 23 in each of the plurality of pixels 21, near-infrared light can be emitted from each of the pixels 21. Since each pixel 21 can detect reflected light from the detection target, the detection accuracy of coordinate detection (position detection) can be further improved.

  In the present embodiment, the near-infrared element 22 is disposed on the main surface of the glass substrate 41 (counter substrate 40) on the array substrate 30 (glass substrate 31) side, between the glass substrate 41 and the counter electrode 42. In addition, the near-infrared element 22 is driven at a predetermined cycle (drive pattern) by controlling the potential difference between the pixel electrode 33 and the counter electrode 42 by being provided in parallel with the color filter 43. Can do. Then, when the detection pattern (sensor signal from the optical sensor element 23) detected by the optical sensor element 23 coincides with the driving pattern (predetermined period) of the near-infrared element 22, the position information of the detected object is acquired. By configuring so that near-infrared light different from the near-infrared light emitted from the near-infrared element 22 is incident (mixed) into the display region 20a of the liquid crystal display panel 20 from the outside by external light such as sunlight. ), The position information (coordinates) of the detected object can be detected correctly. That is, malfunction can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, an example in which near infrared light can be emitted from the display area of the liquid crystal display panel has been described. However, the present invention is not limited thereto, and invisible light other than near infrared light can be emitted. It may be configured.

  Moreover, in the said embodiment, although the example which formed the near-infrared element and the optical sensor element in each of several pixels was shown, this invention is not restricted to this, In some pixels of several pixels, You may form a near-infrared element and an optical sensor element. Moreover, you may form a near-infrared element and a photosensor element in a separate pixel.

  In the above embodiment, an example in which a near-infrared element and a photosensor element are formed in a pixel has been described. However, the present invention is not limited to this, and a near-infrared element and a photosensor element are formed outside a pixel. Also good.

  In the above embodiment, an example in which the liquid crystal display panel is configured in an active matrix structure has been described. However, the present invention is not limited to this, and an active matrix can be used as long as a near-infrared element can be driven independently of a pixel. You may comprise in structures other than a structure. For example, the near-infrared element may be driven by forming a passive matrix structure.

  In the above embodiment, an example in which the liquid crystal layer is composed of TN liquid crystal has been described. However, the present invention is not limited to this, and the liquid crystal layer may be composed of liquid crystal other than TN liquid crystal.

  Note that the arrangement of the sub-pixels of the liquid crystal display panel may be a delta arrangement as shown in FIG. 14, for example. Specifically, the red (R), green (G), and blue (B) sub-pixels 301R, 301G, and 301B and the near-infrared element 322 are formed in a substantially square shape when viewed in plan. Are arranged as shown in FIG. Thereby, the pixel 300 including the three sub-pixels 301R, 301G, and 301B, the near-infrared element 322, and the optical sensor element 323 and arranged in a delta shape can be configured.

It is sectional drawing which showed the structure of the liquid crystal display device by one Embodiment of this invention. 1 is a plan view illustrating a pixel configuration of a liquid crystal display device according to an embodiment of the present invention. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention. It is a perspective view of the liquid crystal display panel in the liquid crystal display device by one Embodiment of this invention. It is a top view for demonstrating the structure of the array board | substrate of the liquid crystal display device by one Embodiment of this invention. It is a circuit diagram which shows a part of circuit formed in the display area in the liquid crystal display device by one Embodiment of this invention. It is the schematic for demonstrating the connection state of the optical sensor element and drive electrode of the liquid crystal display device by one Embodiment of this invention. It is an equivalent circuit diagram of an optical sensor element. 1 is a block diagram illustrating a part of a liquid crystal display device according to an embodiment of the present invention. It is the figure which showed an example of the content of the optical sensor element input table of a memory part. It is the schematic for demonstrating operation | movement of the liquid crystal display device by one Embodiment of this invention. 4 is a timing chart illustrating a driving signal for driving the optical sensor element of the liquid crystal display device according to the embodiment of the present invention. 4 is a timing chart illustrating a driving signal for driving the optical sensor element of the liquid crystal display device according to the embodiment of the present invention. It is the top view which showed the pixel structure of the liquid crystal display device by the modification of one Embodiment.

Explanation of symbols

10 Backlight unit (lighting unit)
20 Liquid crystal display panel 20a Display area (pixel area)
22 Near-infrared element (wavelength conversion element)
22a Red filter layer 22b Near infrared phosphor layer 23 Photosensor element 25, 26 Drive electrode 27 Output electrode 30 Array substrate 31 Glass substrate (second substrate)
33 Pixel electrode 40 Counter substrate 41 Glass substrate (first substrate)
42 Counter electrode 43 Color filter 50 Liquid crystal layer 51, 52 Linearly polarizing plate 60 Control unit 61 Memory unit 70 Pixel drive circuit unit 80 Photosensor element drive circuit unit 90 Backlight drive circuit unit

Claims (4)

A liquid crystal display panel including a pixel region in which a plurality of pixels are two-dimensionally arranged;
An illuminating unit facing one main surface of the liquid crystal display panel and irradiating a pixel region of the liquid crystal display panel;
In the pixel region of the liquid crystal display panel, the visible light from the illumination unit is converted into invisible light, and the converted invisible light is emitted to the other main surface side opposite to the one main surface. A wavelength conversion element and a plurality of optical sensor elements that detect invisible light wavelength-converted by the wavelength conversion element are formed ,
The wavelength changing element has a multilayer structure in which a red filter layer and a near infrared phosphor layer are formed from the illumination unit side,
The red filter layer has a function of transmitting the wavelength component of red light in visible light from the illumination unit,
The near-infrared phosphor layer has a function of converting red light transmitted through the red filter layer into near-infrared light, and a liquid crystal display device. A liquid crystal display panel including a pixel region in which a plurality of pixels are two-dimensionally arranged;
An illuminating unit facing one main surface of the liquid crystal display panel and irradiating a pixel region of the liquid crystal display panel;
In the pixel region of the liquid crystal display panel, the visible light from the illumination unit is converted into invisible light, and the converted invisible light is emitted to the other main surface side opposite to the one main surface. A wavelength conversion element and a plurality of optical sensor elements that detect invisible light wavelength-converted by the wavelength conversion element are formed,
Invisible light converted by the wavelength conversion element is infrared light,
The optical sensor element, Ri Oh infrared light receiving element for detecting the infrared light,
The wavelength changing element has a multilayer structure in which a red filter layer and a near infrared phosphor layer are formed from the illumination unit side,
The red filter layer has a function of transmitting the wavelength component of red light in visible light from the illumination unit,
The near-infrared phosphor layer converts red light that has passed through the red filter layer into near-infrared light.
A liquid crystal display device characterized by having a function . A liquid crystal display panel including a pixel region in which a plurality of pixels are two-dimensionally arranged;
An illuminating unit facing one main surface of the liquid crystal display panel and irradiating a pixel region of the liquid crystal display panel;
In the pixel region of the liquid crystal display panel, the visible light from the illumination unit is converted into invisible light, and the converted invisible light is emitted to the other main surface side opposite to the one main surface. A wavelength conversion element and a plurality of optical sensor elements that detect invisible light wavelength-converted by the wavelength conversion element are formed,
The liquid crystal display panel is
A first substrate;
A second substrate disposed closer to the illumination unit than the first substrate and facing the first substrate at a predetermined interval;
A liquid crystal layer sandwiched between the first substrate and the second substrate,
On the main surface of the second substrate on the first substrate side, a plurality of pixel electrodes are formed, while on the main surface of the first substrate on the second substrate side, facing the pixel electrodes. A counter electrode is formed,
The wavelength conversion element is formed on a main surface of the first substrate on the second substrate side, and is formed between the first substrate and the counter electrode.
By applying a voltage between the pixel electrode and the counter electrode, invisible light is emitted from the wavelength conversion element to the other main surface side of the liquid crystal display panel at a predetermined period. And
The liquid crystal display device according to claim 1, wherein position information of an object to be detected is acquired when a detection signal detected by the optical sensor element coincides with the predetermined period . A liquid crystal display panel including a pixel region in which a plurality of pixels are two-dimensionally arranged;
An illuminating unit facing one main surface of the liquid crystal display panel and irradiating a pixel region of the liquid crystal display panel;
In the pixel region of the liquid crystal display panel, the visible light from the illumination unit is converted into invisible light, and the converted invisible light is emitted to the other main surface side opposite to the one main surface. A wavelength conversion element and a plurality of optical sensor elements that detect invisible light wavelength-converted by the wavelength conversion element are formed,
The liquid crystal display panel is
A first substrate;
A second substrate disposed closer to the illumination unit than the first substrate and facing the first substrate at a predetermined interval;
A liquid crystal layer sandwiched between the first substrate and the second substrate,
On the main surface of the second substrate on the first substrate side, a plurality of pixel electrodes are formed, while on the main surface of the first substrate on the second substrate side, facing the pixel electrodes. A counter electrode is formed,
The wavelength conversion element is formed on a main surface of the first substrate on the second substrate side, and is formed between the first substrate and the counter electrode.
By applying a voltage between the pixel electrode and the counter electrode, invisible light is emitted from the wavelength conversion element to the other main surface side of the liquid crystal display panel at a predetermined period. And
When the detection signal detected by the optical sensor element coincides with the predetermined period, the position information of the detected object is acquired,
The liquid crystal display panel is configured to be capable of emitting invisible light from the plurality of wavelength conversion elements at different periods .

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