JP3999887B2 - Light detection digitizing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light detection digitizer that detects a position through light, and more particularly to a light detection digitizer that can be incorporated into a display panel.
[0002]
[Prior art]
Conventionally, a semiconductor position detector called a PSD element has been developed. This irradiates a thin incident light beam to a pn junction surface having a large area, diverts a photocurrent at the irradiated portion in a plurality of directions, and measures them to determine the irradiation position of the incident light beam. It is a technology of detecting.
[0003]
[Problems to be solved by the invention]
On the other hand, in recent years, a type that combines a panel having a display function and a pen input panel has been developed. Conventionally, a so-called “hybrid method” in which various types of pen input panels and display panels are simply overlapped has been developed. It has been adopted. However, when the PSD element is attached to the entire surface of a display panel (for example, a liquid crystal display panel), there is a problem that the cost increases.
[0004]
On the other hand, a type in which a panel having a display function and a pen input panel are integrated has been developed, which uses, for example, electrostatic coupling between the pen input panel and the input pen, and the input pen and the pen input panel. There is a problem that a cord is required to connect between.
[0005]
Therefore, the present invention provides a technique for realizing a light detection type digitizer that can be incorporated in a liquid crystal display panel and does not require a cord for connecting an input pen and a pen input panel.
[0006]
[Means for Solving the Problems]
  According to a first aspect of the present invention, a plurality of first scanning lines, a plurality of second scanning lines intersecting with each of the first scanning lines, the first scanning lines, and the second scanning lines are provided. Provided in the vicinity of the intersection with the first scanning line and connected between the first scanning line and the second scanning line forming the intersection.A light detection digitizing method for a liquid crystal display panel having a liquid crystal display element, comprising: a series connection body of a light detection element and a transistor connected between the adjacent first scanning lines; The electrode is connected to the second scanning line, and when the second scanning line is activated, a signal is input from one of the first scanning lines to the series connection body, and the adjacent second one is A signal is detected from one scanning line.
[0007]
  According to a second aspect of the present invention, the optical detection digitizing according to the first aspect is provided.Jing methodBecauseThe light detection is performed in a period different from the display period of the liquid crystal display panel..
[0008]
  According to claim 3 of the present invention,Claim 1 orThe light detection digitizer according to claim 2.Jing methodBecauseThe photodetecting element has a configuration in which n-type amorphous silicon, i-type amorphous silicon, and n-type amorphous silicon are connected in series..
[0017]
  Claim of the invention5According to the present invention, a plurality of first scanning lines, a plurality of second scanning lines intersecting each of the first scanning lines, and a vicinity of an intersection of the first scanning line and the second scanning line A liquid crystal display cell connected between the first scan line and the second scan line forming the intersection;A light detection digitizing method for a liquid crystal display panel comprising:Each of the liquid crystal display cells includes a gate connected to the first scan line, a first current electrode connected to the second scan line, and a second current electrode.Placed at the position where only light reachesA transistor; a first pixel electrode connected to the second current electrode of the transistor; a liquid crystal body; and a second pixel electrode sandwiching the liquid crystal body together with the first pixel electrode.ShiA common AC signal is applied to the second pixel electrode of each liquid crystal display cell, and the first and second scanning lines are used.Leakage current of the transistor having an AC waveform of the AC signalA light detection digitizing method for detecting a signal.
A sixth aspect of the present invention is the light detection digitizing method according to the fifth aspect, wherein the light detection is performed in a period different from the display period of the liquid crystal display panel.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
A. Basic configuration of a light detection digitizer:
Liquid crystal display panels generally have liquid crystal display cells arranged in a matrix. Therefore, in order to incorporate the light detection type digitizer into the liquid crystal display panel, it is desirable to arrange the light detection elements in a matrix. In this section, a light detection type digitizer having light detection elements arranged in a matrix that can be incorporated into a liquid crystal display panel will be described.
[0019]
FIG. 1 is a plan view schematically showing the configuration of the light detection type digitizer described in this section and the next section. The column scanning lines X1 to X5 intersect with each of the row scanning lines Y1 to Y5, and a light detection element Sij is provided at the intersection of the row scanning line Yi and the column scanning line Xj (i = 1 to 1). 5, j = 1-5). The row scanning lines Y1 to Y5 are sequentially applied with a pulsed potential by the pulse voltage generation circuit 701 (hereinafter also referred to as “the row scanning line is activated”), and the detection circuit 702 uses the column scanning line. A current flowing through X1 to X5 is detected.
[0020]
As the light sensing element Sij, a single crystal, a semiconductor having a non-single crystal (including amorphous or polycrystalline) pn junction, or a non-single crystal semiconductor is employed. For example, silicon can be used as the semiconductor. In this case, it is desirable in terms of efficiency that the light incident on the light detection element Sij has a wavelength of 0.4 to 1.2 μm. The illuminance is desirably 100 lux or more. In addition, it is desirable in terms of characteristics that amorphous silicon does not contain phosphorus or boron.
[0021]
When the photodetecting element Sij is formed of a semiconductor having a pn junction, it is desirable in terms of efficiency and accuracy that the junction surface is substantially perpendicular to the light input direction. It is desirable to apply a reverse bias to the pn junction.
[0022]
Embodiment 1 FIG.
FIG. 2 partially shows a specific configuration of the light detection type digitizer according to the present exemplary embodiment. FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along a cutting line B1-B1 in FIG.
[0023]
The light detection type digitizer has a substrate 101 having an insulating surface at least on its surface, and column scanning lines X1 to X5 and light detection elements S11 to S55 are provided on the upper surface (FIG. 2 shows only a part of them). ing). One side of each of the light detection elements S11 to S55 is electrically connected adjacent to any one of the column scanning lines X1 to X5. Of the light detection elements S11 to S55, the side facing the side adjacent to the column scanning lines X1 to X5 has a protruding portion extending in parallel with the column scanning lines X1 to X5 from the row scanning lines Y1 to Y5. The column scanning lines X1 to X5 and the light detection elements S11 to S55 are, for example, SiO except for the top surfaces of the row scanning lines Y1 to Y5.₂It is covered with a light-transmitting insulating film 102 formed in (1). Further, the light-transmitting insulating film 102 and the row scanning lines Y1 to Y5 are made of, for example, SiO.₂It is covered with a translucent protective film 103 formed in (1).
[0024]
Among the photodetecting elements S11 to S55, the side adjacent to the column scanning lines X1 to X5 and the vicinity of the side where the protruding portions of the row scanning lines Y1 to Y5 are located are the column scanning lines X1 to X5 and the row scanning lines Y1 to Y1, respectively. In order to improve the electrical connection with Y5, it is desirable to increase the impurity concentration. FIG. 4C shows a cross-sectional view at the same position as FIG. 2B, and schematically shows the portion where the impurity concentration is increased by satin hatching.
[0025]
In the light detection type digitizer having such a configuration, for example, a case where light is input with a light pen into a region indicated by a circle in FIG. FIG. 3 is a cross-sectional view showing how the light L1 is incident by the light pen 700. As shown in FIG. FIG. 4 is a timing chart showing the translucent operation of the light detection digitizer.
[0026]
The row scanning lines Y1 to Y5 receive a pulse voltage line-sequentially by the pulse voltage generation circuit 701, and the current flowing through the column scanning lines X1 to X5 is detected by the detection circuit 702 each time. Since the light detection element S33 receives the light L1, a larger amount of photocurrent flows than other light detection elements. Therefore, when the row scanning line Y3 is activated, the current flowing through the column scanning line X3 is larger than the current flowing through the column scanning lines X1 to X5 in other cases. Therefore, it is possible to detect that the light is irradiated in the vicinity of the light detection element S33, that is, the position of the light pen 700.
[0027]
FIG. 5 shows another specific configuration of the light detection type digitizer. The figure (a) is a top view, The figure (b) is sectional drawing in the cutting line B2-B2 in the figure (a). The structure shown in FIG. 5 is different from the structure shown in FIG. 2 in that an optical filter FLij is added to each upper surface of the light detection element Sij (the boundary between the light detection element Sij and the insulating film 102). is doing. By setting the characteristics of the optical filter FLij so that only the vicinity of the wavelength of the light irradiated by the light pen 700 is transmitted, it is possible to suppress the influence of external light and to detect light more accurately. Of course, as shown in FIG. 2C, the impurity concentration of a part of the photodetecting elements S11 to S55 can be increased.
[0028]
Embodiment 2. FIG.
The configuration shown in FIG. 2 can also perform a light-shielding type operation when the light detection elements S11 to S55 are shielded and position detection is performed. This is because, for example, the region indicated by a circle in FIG.
[0029]
However, when the light detection digitizer is incorporated into the liquid crystal display panel, the light detection digitizer must be disposed closer to the operator than the liquid crystal display panel because of the operability of the input pen. Therefore, the light detection digitizer must transmit the display light of the liquid crystal display panel, that is, the transmitted light from the back surface or the reflected light of the incident light from the display surface. In order to meet such a requirement, it is necessary to employ a light-transmitting substrate 101 a as the substrate 101.
[0030]
FIG. 6 partially shows a specific configuration of the light detection type digitizer according to the present exemplary embodiment. The figure (a) is a top view, The figure (b) is sectional drawing in the cutting line B3-B3 in the figure (a). The light detection type digitizer shown in FIG. 6 is different from the light detection type digitizer shown in FIG. 2 in that the substrate 101 is replaced with a light-transmitting and insulating substrate 101a, and the bottom surface of each of the light detection elements Sij ( It has a structure in which a light shielding film SHij is additionally provided at the boundary between the light detection element Sij and the substrate 101a. Of course, also in the light detection type digitizer, the impurity concentration of a part of the light detection elements S11 to S55 can be increased as shown in FIG.
[0031]
FIG. 7 is a cross-sectional view showing how the external light LG is shielded by the light-shielding pen 703. FIG. 8 is a timing chart showing the light shielding type operation of the light detection digitizer.
[0032]
Since the external light LG from the upper surface side (protective film 103 side) of the light detection element Sij is shielded by using the light blocking pen 703, for example, above the light detection element S33, only the corresponding photocurrent is reduced. The position of the light shielding pen 703 can be detected. In addition, since the light shielding film SHij is provided, even if the substrate 101a is translucent, it is possible to prevent the display light of the liquid crystal display panel from being irradiated to the light detection element Sij from the lower surface, thereby avoiding false detection and accuracy deterioration. can do.
[0033]
Of course, the light detection type digitizer shown in FIG. 6 can be operated in a transmissive manner. In that case, the light detection element Sij may be sandwiched from above by the optical filter FLij and from below by the light shielding film SHij.
[0034]
In the example shown above, the case where the light detection element Sij is operated by the light pen 700 or the light shielding pen 703 from the protective film 103 side is shown. In this case, when a transmissive operation is performed, the backlight is irradiated from the substrate 101a side. However, of course, the backlight may be irradiated from the protective film 103 side, and the light detection element Sij may be operated by the light pen 700 or the light shielding pen 703 from the substrate 101a side. In this case, it goes without saying that the light shielding film SHij is provided on the protective film 103 side with respect to the light detection element Sij, and the optical filter FLij is provided on the substrate 101a side with respect to the light detection element Sij.
[0035]
B. Incorporating a light detection digitizer into a liquid crystal display panel:
In this section, various modes when the light detection type digitizer based on the mode shown in the previous section is incorporated on the display surface side of the liquid crystal display panel will be described.
[0036]
Embodiment 3 FIG.
FIG. 9 partially shows a specific configuration of the light detection type digitizer according to the present exemplary embodiment. The configuration shown in FIG. 9 is a direct matrix type below the configuration shown in FIG. 2, and a reflective liquid crystal display panel that reflects external light from the display surface to visually recognize the display is provided. can get. A light detection element of a light detection type digitizer is provided corresponding to each pixel of the liquid crystal display panel.
[0037]
FIG. 4A is a plan view, and FIGS. 2B and 2C are cross-sectional views taken along cutting lines B4-B4 and C4-C4 in FIG. 1A, respectively. However, in FIG. 6A, the structure below the liquid crystal LC is not shown in order to avoid complication of the drawing. However, the first pixel electrode Faij provided on the display surface side of the liquid crystal LC is indicated by a broken line. Further, in FIGS. 5B and 5C, spacers for partitioning the liquid crystal for each pixel are also omitted. Such simplification of the drawings is also performed in the following description of embodiments.
[0038]
Compared with the configuration shown in FIG. 2, the insulating film 102 is also provided below the lower surfaces of the photodetecting elements Sij and the column scanning lines Xj, and these are insulated from the first pixel electrodes Faij. Yes. That is, the insulating film 102 also functions as the light-shielding substrate 101a having the configuration shown in FIG. The light detection element Sij is designed to be smaller than the first pixel electrode Faij, and suppresses the extent to which the light detection element Sij hinders liquid crystal display.
[0039]
The first pixel electrode Faij is a transparent electrode such as ITO. Below the first pixel electrode Faij, a second pixel electrode Fbij is provided opposite to the first pixel electrode Faij and for applying a voltage across the liquid crystal element LC together with the first pixel electrode Faij. Yes. The second pixel electrode Fbij is formed of a metal including, for example, aluminum or silver and has a function of reflecting external light from the display surface.
[0040]
On the other hand, at least the surface of the column scanning line Gbj is provided on the insulating substrate 201 and is covered with the insulating film 202 together with the substrate 201, and is electrically connected to the second pixel electrode Fbij through a local through hole. The The first pixel electrode Faij is in contact with and electrically connected to the row scanning line Gai. Here, since a reflective liquid crystal display panel is illustrated, the substrate 201 and the insulating film 202 do not need to be translucent.
[0041]
In this way, by integrating the liquid crystal display panel and the light detection digitizer, it is possible to have both functions as a liquid crystal display and a pen input panel.
[0042]
The row scanning lines Gai and the column scanning lines Gbj for liquid crystal display are provided separately from the row scanning lines Yi and column scanning lines Xj for light detection, so that the light detection is performed separately from the timing for driving the liquid crystal display panel. The digitizer can be driven.
[0043]
Moreover, since the row scanning lines Yi and the column scanning lines Xj for light detection are respectively provided above the row scanning lines Gai and the column scanning lines Gbj for liquid crystal display, these scanning lines for the light detection digitizer are displayed on the liquid crystal display. It is hard to deteriorate visibility.
[0044]
In addition, a row scanning line Yi for light detection, a column scanning line Xj for light detection, a row scanning line Gai for liquid crystal display, and a column scanning line Gbj for liquid crystal display are arranged in order from the side farther from the display surface. Yes. Therefore, the column scan line Xj for light detection is between the row scan line Yi for light detection and the row scan line Gai for liquid crystal display, and the column scan line Xj for light detection and the column scan line for liquid crystal display. Since the liquid crystal display row scanning lines Gai are interposed between Gbj, interference between the two types of row scanning lines and between the two types of column scanning lines can be suppressed.
[0045]
Of course, similarly to the structure shown in FIG. 5, an optical filter FLij can be provided on the upper surface of the light detection element Sij. FIG. 10 is a cross-sectional view showing such a modification, and is a cross-sectional view corresponding to the portion shown in FIG. In such a modification, a cross-sectional view corresponding to the portion shown in FIG. 9C appears in the same manner as FIG. 9C.
[0046]
Further, similarly to the structure shown in FIG. 6, a light shielding film SHij can be provided on the lower surface of the light detection element Sij. FIG. 11 shows such a modification. FIG. 11A is a plan view, and FIGS. 11B and 11C are cross-sectional views taken along cutting lines B5-B5 and C5-C5 in FIG. is there. Furthermore, an optical filter FLij can be provided on the upper surface of the light detection element Sij. FIG. 12 is a cross-sectional view showing such a modification, and is a cross-sectional view corresponding to the portion shown in FIG.
[0047]
Embodiment 4 FIG.
Under the configuration shown in FIG. 2, a two-terminal active matrix type liquid crystal display panel can be provided, although it is not a direct matrix type. FIG. 13 is a cross-sectional view showing such a configuration, and is a cross-sectional view corresponding to the portion shown in FIG. In such a configuration, a cross-sectional view corresponding to the portion shown in FIG. 9B appears in the same manner as in FIG. 9 is different from the structure shown in FIG. 9 only in that a nonlinear element NLij is provided between the second pixel electrode Fbij and the column scanning line Gbj.
[0048]
Alternatively, a three-terminal active matrix liquid crystal display panel can be provided under the structure shown in FIG. FIG. 14 is a cross-sectional view showing such a modification, and FIGS. 14A and 14B are cross-sectional views corresponding to the portions shown in FIGS. 9B and 9C, respectively.
[0049]
Compared to the structure shown in FIG. 9, the following points are different. First, the first pixel electrode Faij is replaced with a continuous pixel electrode Fa. Therefore, the shape of the first pixel electrode Faij indicated by the broken line in FIG. 9A appears as the shape of the second pixel electrode Fbij in the present embodiment.
[0050]
A pair of current electrodes of the transistor Qij is connected between the second pixel electrode Fbij and the column scan line Gbj. A row scanning line Gai is laid under the second pixel electrode Fbij, the column scanning line Gbj, and the transistor Qij through an insulating film 203, which penetrates through the insulating film 203 in a cross section (not shown) to form the transistor Qij. Connected to the control electrode. The row scanning line Gai is provided on the substrate 201. Here, a reflective liquid crystal display panel is illustrated, so that the insulating film 203 does not need to be light-transmitting, like the substrate 201 and the insulating film 202.
[0051]
Even in such a structure, the column scan line Xj for light detection, the pixel electrode Fa, and the column scan line Gbj for liquid crystal display are arranged between the row scan line Yi for light detection and the row scan line Gai for liquid crystal display. Since the pixel electrode Fa is interposed between the column scanning line Xj for light detection and the column scanning line Gbj for liquid crystal display, each of the two types of row scanning lines is between two types of column scanning lines. Interference can be suppressed.
[0052]
Note that the pixel electrode Fa is not necessarily formed as a single connected body. For example, it may be continuous only in the direction in which the row scanning line Yi extends, and a metal wiring may be laid at a position appearing as the pixel electrode Fa in FIG. 5B, and the pixel electrode Fa may be connected.
[0053]
Of course, the optical filter FLij can be provided on the upper surface of the light detection element Sij, or the light shielding film SHij can be provided on the lower surface.
[0054]
Embodiment 5 FIG.
FIG. 15 partially shows a specific configuration of the light detection type digitizer according to the present exemplary embodiment. The configuration shown in FIG. 15 is a direct matrix type below the configuration shown in FIG. 2, and a transmissive liquid crystal that allows the external light applied from the side opposite to the display surface to pass through to visually recognize the display. Obtained by providing a display panel. A light detection element of a light detection type digitizer is provided for each pixel of the liquid crystal display panel.
[0055]
FIGS. 9A and 9B are cross-sectional views corresponding to the portions shown in FIGS. 9B and 9C, and the plan view appears in the same manner as FIG. 9A.
[0056]
Compared with the configuration shown in FIG. 9, a light-transmitting and insulating substrate 302 made of glass, for example, is used instead of the substrate 201 whose light-transmitting property is not required. Instead of the insulating film 202, a light-transmitting insulating film 303 is used. The second pixel electrode Fbij is also formed of a transparent electrode.
[0057]
Such a configuration has the same effect as the configuration shown in FIG. 9, although there is a difference between the reflective type and the translucent type.
[0058]
FIGS. 16A and 16B are sectional views showing modifications of the present embodiment, and correspond to FIGS. 15A and 15B, respectively. In the configuration shown in FIG. 16, in the configuration shown in FIG. 15, the second pixel electrode Fbij also serves as the column scanning line Gbj for liquid crystal display. The difference is that the insulating substrate 301 is provided. Such a configuration also has the same effect as in FIG.
[0059]
Embodiment 6 FIG.
A two-terminal active matrix liquid crystal display panel can also be provided in a light-transmitting light detection type digitizer. FIG. 17 is a cross-sectional view showing such a configuration, and is a cross-sectional view corresponding to FIG. 17 has a structure in which the substrate 201 and the insulating film 203 shown in FIG. 13 are replaced with a light-transmitting substrate 302 and a light-transmitting insulating film 303, respectively.
[0060]
A three-terminal active matrix liquid crystal display panel can also be provided. FIG. 18 is a cross-sectional view showing such a modification. 18A and 18B are cross-sectional views corresponding to FIGS. 15A and 15B, respectively. The substrate 201 and the insulating film 202 shown in FIG. In this structure, 203 is replaced with a light-transmitting and insulating substrate 302 and light-transmitting insulating films 304 and 303, respectively.
[0061]
Also in the light detection digitizer incorporated in the light-transmitting liquid crystal display panel shown in the fifth and sixth embodiments, the light filter FLij is provided on the upper surface of the light detection element Sij, and the light-shielding film SHij is provided on the lower surface. Needless to say, you can.
[0062]
Embodiment 7 FIG.
FIG. 19 is a cross-sectional view showing the configuration of the present embodiment. FIGS. 19A and 19B correspond to FIGS. 9B and 9C, respectively.
[0063]
In this embodiment mode, a light detection digitizer is incorporated in a reflective and direct matrix type liquid crystal display panel which performs color display. In a liquid crystal display panel that performs color display, a liquid crystal display cell performs display for each pixel, and a plurality of types of color filters are provided to face the liquid crystal display cell. In order to perform display for each pixel, a pair of three second pixel electrodes Fb32, Fb33, and Fb34 are opposed to one first pixel electrode Fa32. Then, the red transmission light filter 107, the green transmission light filter 108, and the blue transmission light filter 106 that face the second pixel electrodes Fb32, Fb33, and Fb34 through the first pixel electrode Fa32, respectively, are a protective film 103 and an insulating film, respectively. 102. A black mask 110 is sandwiched between the red transmission light filter 107, the green transmission light filter 108, and the blue transmission light filter 106. Further, a black mask 110 is provided above the horizontal scanning electrode Y3, and display light is separated between different filters.
[0064]
The red transmitted light filter 107 is provided to face the second pixel electrode Fb32 via the light detection element S32, so that the light detection element S32 efficiently receives red light. This is because when the photodetecting element is made of amorphous silicon, the intensity of the photocurrent is sensitive to the near infrared wavelength. In such a configuration, the number of column scanning lines Xj for light detection is approximately 1/3 of the column scanning lines Gbj for liquid crystal display.
[0065]
When a light detection digitizer is incorporated in a liquid crystal display panel that performs color display in this manner, it is not necessary to separately form a light filter FLij, and light having a wavelength with good sensitivity is given to the light detection element with a simple configuration. Therefore, accurate position detection can be performed while suppressing the influence of external light.
[0066]
Embodiment 8 FIG.
In the third to seventh embodiments, the case where the light detection elements Sij are discretely provided corresponding to each pixel has been described. However, the light detection elements may be continuously extended.
[0067]
20 is a plan view showing the configuration of the light detection digitizer according to the present embodiment, and FIGS. 21 and 22 are cross-sectional views taken along the cutting lines Z1-Z1 and Z2-Z2 shown in FIG. 20, respectively. Here, a case is shown in which a light detection grid DET having a pn junction and arranged in a grid is provided in a reflective liquid crystal display panel.
[0068]
A thin film transistor (TFT) T on a substrate 601 having an insulating surface at least_ijAnd a gate line G as a gate thereof._jThe projecting part from is functioning, and the source is the source line S_iThe drain is a pixel electrode E that reflects external light._ijAre connected to each other. However, in FIG. 20, the pixel electrode E_ijIn order to avoid complication of the drawing due to hidden lines, though the pixel electrode E is positioned closest to the paper surface, the pixel electrode E_ijIs indicated by a two-dot chain line, and the source line S located on the rear side of the drawing with respect to this is shown in FIG._iAnd transistor T_ijIs shown as a solid line.
[0069]
A p-type non-single crystal silicon 618 and an n-type non-single crystal silicon 617 are stacked in this order on an insulating substrate 601 with the electrode ELE as a base. The p-type non-single-crystal silicon 618 and the n-type non-single-crystal silicon 617 constitute a light detection grid DET and perform light detection in the same manner as the PSD element. Source line S_i, Gate line G_j, Transistor T_ijThe electrode ELE and the light detection grid DET are covered with a light-transmitting insulating film 602.
[0070]
The insulating film 602 has a pixel electrode E_ijThe liquid crystal body LC, the transparent electrode Fa, and the translucent protective film 603 are laminated in this order. Pixel electrode E_ijHas a function of reflecting light incident from the display surface (the protective film 603 side) as well as a function of driving the liquid crystal LC. Photodetection grid DET is gate line G_jAs for the extending direction of the pixel electrode E of the adjacent liquid crystal display cell_ij, E_{(i + 1) j}Between the source lines S_iAs for the extending direction of the gate line G_{j + 1}And pixel electrode E_ij, E_{(i + 1) j}In between, external light can be received through the insulating film 602, the liquid crystal LC, and the transparent electrode Fa. In a normal reflective liquid crystal display panel, the light-transmitting property of the insulating film 602 is not a problem. However, in this embodiment, the light-transmitting property of the insulating film 602 is required because external light needs to reach the light detection grid DET. . The same configuration is provided for other liquid crystal display cells.
[0071]
If a terminal is provided around the entire grating for the light detection grid DET configured in this manner, the position where light is incident can be detected based on the same principle as the PSD element. Even if the light detection grids DET are laid in parallel only in one direction, for example, the direction in which the gate lines or the source lines extend, even if they are not in a lattice shape, light detection along these directions is possible.
[0072]
Embodiment 9 FIG.
The light detection grid DET used in Embodiment 9 can also be applied to a translucent liquid crystal display panel. FIG. 23 is a partially broken plan view showing the configuration of the light detection digitizer according to the present embodiment, and FIG. 24 is a cross-sectional view taken along the cutting line ZZ shown in FIG.
[0073]
The configuration shown in the ninth embodiment is that the light detection grid DET and the gate line G_jThe electrode ELE is located on the source line S more than the light detection grid DET, the point that the substrate 601 is replaced with a light-transmitting and insulating substrate 601a._iTransistor T_ijIs different in that a light shielding film 604a is provided between the liquid crystal LC and the transparent electrode Fa. The backlight BL is given from the protective film 603 side, while the incident light L3 from the light pen is given from the substrate 601a side. That is, the display surface of the liquid crystal is on the substrate 601a side, and the back surface is on the protective film 603 side.
[0074]
In such a configuration, the light detection grid DET, the transistor T_ijDoes not disturb the LCD display. In other words, the light detection grid DET is connected to the source line S._iAnd gate line G_jCompared with the case where the area is not hidden below, a decrease in the area of the liquid crystal display is suppressed. Transistor T of light shielding film 604a_ijAs with the light shielding function for the source line S_iAnd gate line G_jFulfills the light blocking function for the light detection grid DET.
[0075]
The electrode ELE has a source line S with respect to the light detection grid DET._iAn arrangement is provided that is provided on the side and does not prevent the incident light L3 from reaching the light detection grid DET from the substrate 601a side.
[0076]
C. Photodetector digitizer sharing display scan line:
In the previous section, the light detection digitizer provided with the light detection scanning lines (Yi, Xj) independently of the display scanning lines (Gai, Gbj) has been described. However, in this section, the display scanning lines are used for light detection scanning. The technology used is also described.
[0077]
Embodiment 10 FIG.
FIG. 25 is a plan view conceptually showing the structure of the light detection digitizer used in the light detection digitizing method according to the present embodiment. The light detection digitizer shown in this embodiment also uses a transistor for driving liquid crystal, which is usually provided in a three-terminal active matrix liquid crystal display panel, for light detection.
[0078]
In the liquid crystal display panel, a plurality of sources and a plurality of gate lines are provided so as to cross each other. For example, the source line S_iAnd gate line G_jNear the intersection of the pixel cells M_ijIs provided. Pixel cell M_ijTransistor T_ijSource, drain and gate of the source line S_i, Pixel electrode E_ij, Gate line G_jIt is connected to the. Pixel electrode E_ijA liquid crystal body (not shown) is located above (on the front side of the drawing in the drawing), and a transparent electrode (not shown) is further provided as a second pixel electrode above the pixel electrode E._ijIn addition, the liquid crystal body is disposed therebetween. The same applies to other pixel cells. The transparent electrode is given a common potential in all the pixel cells by a common wiring (not shown), and the pixel electrode E_ijAt the same time, a voltage is applied to the liquid crystal.
[0079]
FIG. 26 shows a pixel cell M_ijIt is a circuit diagram which shows an electrical equivalent circuit. However, transistor T_ijStorage capacitor C connected to the drain of_ijIs not shown in FIG. Liquid crystal N_ijIncludes a liquid crystal body and transistor T_ijOn the side connected to the drain of the pixel electrode E_ijAnd a transparent electrode is disposed on the side connected to the common wiring line COM.
[0080]
In a display period for performing liquid crystal display, a predetermined fixed potential is applied to the common wiring line COM, while the gate lines G are sequentially lined up._jIs activated and the source electrode S_iA display signal is applied to the liquid crystal N_ijA voltage is applied to the display to display.
[0081]
On the other hand, in the light detection period for performing light detection, an AC signal, for example, a pulse wave is input to the common wiring COM. And gate line G_jAnd source line S_iMeasure the potential. The AC signal applied to the common wiring line COM is a transparent electrode and a liquid crystal N_ijThrough the transistor T_ijGiven to the drain. Thus transistor T_ijWhether or not light is irradiated to the gate line G_jAnd source line S_iIt is possible to determine whether or not the AC waveform based on the AC signal applied to the common wiring COM is largely reflected in the potential. Transistor T if exposed to light_ijThis is because leakage due to photoexcitation increases.
[0082]
Note that the AC signal applied to the common wiring COM desirably has a frequency that is three times higher than the commercial frequency, for example, a frequency that is 180 Hz or higher, in order to avoid noise due to the influence of the commercial frequency.
[0083]
As described above, the common line COM and the gate line G are used in the display period and the light detection period._jAnd source line S_iSince the functions performed by are different, both periods are provided alternately. FIG. 27 is a schematic diagram showing the relationship between the light detection period TA and the display period TB. The period TC is the sum of the light detection period TA and the display period TB.
[0084]
In a normal three-terminal active matrix liquid crystal display panel, for example, 1/60 second is allocated to one frame. Therefore, in this embodiment, for example, the display for one frame is thinned out once every 1/2 to 1 second, and is applied to the light detection operation. Specifically, the light detection period TA is set to 1/60 seconds, the display period TB is set to 39/60 seconds, and the period TC is repeated every 2/3 seconds.
[0085]
Alternatively, the liquid crystal display operation includes a blanking period in one frame during which no display is actually performed. Therefore, this blanking period may be applied to the light detection period TA. In this case, for example, the light detection period TA is set to 1/6000 seconds, the display period TB is set to 99/6000 seconds, and the period TC is set to 1/60 seconds for one frame.
[0086]
FIG. 28 shows a structure of a transmissive liquid crystal display panel, and shows a cross section taken along the section line B6-B6 of FIG. For example, the gate line G is formed on a translucent substrate 601a made of glass._jAnd the gate line G_jIs covered with a gate insulating film 501. An i-type semiconductor layer 502 is provided on the gate insulating film 501, and n-type semiconductor layers 503 and 504 are provided at both ends thereof. The n-type semiconductor layers 503 and 504 have source lines S respectively._iAnd drain line DR_ijIs connected. That is, the transistor T as a bottom gate type TFT._ijIs configured. Pixel electrode E_ijIs the drain line DR_ijThrough the transistor T_ijConnected to.
[0087]
These transistors T_ij, Gate line G_j, Source line S_iAnd drain line DR_ijIs covered with a light-transmitting insulating film 602, and a liquid crystal body LC is provided over the light-transmitting insulating film 602. A transparent electrode Fa and a translucent protective film 603 are further formed on the liquid crystal body LC._ijIs unnecessary, so that the transistor T between the liquid crystal LC and the transparent electrode Fa_ijA light shielding film 604a is provided above the light shielding layer. Even if the light shielding film 604a exists, the light provided from the light pen reflects and propagates in the liquid crystal LC as in the illustrated light L2, and the transistor T_ijTo reach the body.
[0088]
FIG. 29 shows a structure of a reflective liquid crystal display panel, and shows a cross section corresponding to FIG. In contrast to the structure shown in FIG. 28, the light-transmitting substrate 601a is replaced with a substrate 601 whose light-transmitting property does not matter. Of course, the substrate 601a may be employed.
[0089]
Transistor T_ij, Gate line G_j, Source line S_i, Drain line DR_ij, And the transparent insulating film 602 is substantially the same as the configuration shown in FIG._ijIs provided on the insulating film 602 and is made of a metal such as aluminum or silver to reflect external light. Further, the light shielding film 604a is not provided, and the source line S is provided between the insulating film 602 and the liquid crystal LC._iA light-shielding film 604b is provided above. Instead of the light shielding film 604b, the pixel electrode E is located at the position._ijMay be extended.
[0090]
In a normal reflective liquid crystal display panel, the transistor T_ijAll over the pixel electrode E_ijThe insulating film 602 is not necessarily light-transmitting. However, in this embodiment, T_ijIn order to make the light L2 from the light pen enter the body of the pixel electrode E,_ijIs partially cut off, or the light shielding film 604b and the pixel electrode E_ijA gap is provided between the insulating film 602 and the insulating film 602.
[0091]
Embodiment 11 FIG.
In this embodiment mode, a structure in which a light detection element is separately provided in a liquid crystal display cell and a detection wiring for the cell line is also used as a gate line and a source line for liquid crystal display is shown.
[0092]
FIG. 30 is a plan view conceptually showing the structure of the light detection digitizer according to the present embodiment. The light detection digitizer shown in this embodiment mode is realized in a three-terminal active matrix liquid crystal display panel.
[0093]
Similarly to FIG. 25, the liquid crystal and the commonly connected transparent electrodes are also omitted in FIG. Pixel cell M_ijTransistor T_ijSource, drain and gate of the source line S_i, Pixel electrode E_ij, Gate line G_jIt is connected to the. On the other hand, the pixel cell M_ijPixel electrode E_ijTransistor Q provided close to_ijThe source, drain and gate are respectively connected to the source line S._i, Light detection element D_ijOne end of the gate line G_{j + 1}Connected to. Photodetector D_ijIs connected to the adjacent source line S._{i + 1}Connected to. That is, the light detection element D_ijAnd transistor Q_ijAre connected to the adjacent source line S._i, S_{i + 1}Connected between. The same applies to other cells.
[0094]
However, L gate lines G₁, G₂, ..., G_LAre provided in this order, the pixel cell M_iLTransistor T_iLAnd light detection element D_iLMay not be provided. This is because the gate line connected to this cannot be used as the gate line used for liquid crystal display. In addition, K source lines S₁, S₂, ..., S_KAre provided in this order, the pixel cell M_KjTransistor T_KjAnd light detection element D_KjMay not be provided. This is because the source line connected to this cannot be used as the source line used for the liquid crystal display. Of course, these elements may be provided, and a gate line and a source line may be provided separately.
[0095]
FIG. 31 is a circuit diagram showing an electrical equivalent circuit of the configuration shown in FIG. Common wiring COM is liquid crystal N_ijAre connected in common to a transparent electrode serving as one of the electrodes. In such a configuration, a display for performing liquid crystal display is realized by the operation shown in the tenth embodiment.
[0096]
Also in the light detection period for performing light detection, the gate lines are activated line-sequentially. And every other source line, for example source line S_i, S_{i + 2}A pulse is input. And every other source line S_{i + 1}, S_{i + 3}To detect a pulse. On the other hand, the light detection element receives light and changes its resistance value or excites a current._{i + 1}If a pulse is detected from the light detection element D_ij, D_{(i + 1) j}It can be detected that light has been irradiated to any of the above. When the same gate line is activated, the source line for inputting the pulse and the source line for detecting the pulse are alternately switched, so that the position of the irradiated light is measured by the signal from the light detecting element. It can be detected with pixel size resolution.
[0097]
As in the tenth embodiment, the source line S is used in the display period and the light detection period._iSince the functions performed by are different, both periods are provided alternately. Therefore, in this embodiment, for example, the display for one frame is thinned out once every 1/2 to 1 second, and is applied to the light detection operation. Specifically, the light detection period TA is set to 1/60 seconds, the display period TB is set to 39/60 seconds, and the period TC is repeated every 2/3 seconds.
[0098]
FIG. 32 shows the light detecting element Q._ijIt is sectional drawing which illustrates the specific structure of. On a substrate 610 having an insulating surface, n-type amorphous silicon 614 and 615 and i-type amorphous silicon 613 sandwiched therebetween are provided. Electrodes 611 and 612 are connected to the n-type amorphous silicon 614 and 615, respectively. Transistor T shown in the tenth embodiment_ijSimilarly to the above, when the i-type amorphous silicon 613 is irradiated with light, photoexcitation occurs, and light is detected.
[0099]
FIG. 33 shows the light sensing element Q._ijIt is sectional drawing which illustrates other specific structures. An n-type non-single-crystal silicon 617 and a p-type non-single-crystal silicon 618 covering a part of the non-single-crystal silicon 617 are provided over a substrate 610 having an insulating surface. Electrodes 611 and 612 are connected to the non-single crystal silicon 617 and 618, respectively. Photoexcitation occurs at the pn junction formed at the boundary between the non-single crystal silicon 617 and 618, and light is detected.
[0100]
In either structure of FIGS. 32 and 33, one of the electrodes 611 and 612 is the source line S._{i + 1}One of which is connected to transistor Q_ijThrough the source line S_iConnected to.
[0101]
【The invention's effect】
  The optical detection digitizing according to claim 1 of the present invention.Jing methodAccording toUsing the first and second scanning lines for the liquid crystal display panel, a signal from the light detection element can be detected.it can.
[0102]
  Of this invention, the optical detection digitizing according to claim 2Jing methodAccording to the above, the operation of the liquid crystal display element and the operation of the light detection digitizer in the liquid crystal display panel are performed independently.UrineYou can.
[0112]
  Claim of the invention5According to the photodetecting digitizing method, the transistor provided in the three-terminal type active matrix liquid crystal display panel can also be used as a photodetecting element by measuring the leakage current due to the photoexcitation current.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing a configuration of a first embodiment and a second embodiment of the present invention.
2A and 2B are a plan view and a cross-sectional view showing the configuration of Embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view showing the operation of the first embodiment of the present invention.
FIG. 4 is a timing chart showing the operation of the first embodiment of the present invention.
5A and 5B are a plan view and a cross-sectional view showing another configuration of the first embodiment of the present invention.
6A and 6B are a plan view and a cross-sectional view showing a configuration of Embodiment 2 of the present invention.
FIG. 7 is a cross-sectional view showing the operation of the second embodiment of the present invention.
FIG. 8 is a timing chart showing the operation of the second embodiment of the present invention.
FIGS. 9A and 9B are a plan view and a cross-sectional view showing a configuration of Embodiment 3 of the present invention. FIGS.
FIG. 10 is a sectional view showing a modification of the third embodiment of the present invention.
FIGS. 11A and 11B are a plan view and a cross-sectional view showing another modification of the third embodiment of the present invention. FIGS.
FIG. 12 is a sectional view showing still another modification of the third embodiment of the present invention.
FIG. 13 is a cross-sectional view showing a configuration of a fourth embodiment of the present invention.
FIG. 14 is a sectional view showing a modification of the fourth embodiment of the present invention.
FIG. 15 is a sectional view showing the configuration of the fifth embodiment of the present invention.
FIG. 16 is a sectional view showing a modification of the fifth embodiment of the present invention.
FIG. 17 is a cross-sectional view showing a configuration of a sixth embodiment of the present invention.
FIG. 18 is a sectional view showing a modification of the sixth embodiment of the present invention.
FIG. 19 is a cross-sectional view showing a configuration of a seventh embodiment of the present invention.
FIG. 20 is a plan view showing the configuration of the eighth embodiment of the present invention.
FIG. 21 is a cross-sectional view showing a configuration of an eighth embodiment of the present invention.
FIG. 22 is a cross-sectional view showing a configuration of an eighth embodiment of the present invention.
FIG. 23 is a plan view showing the configuration of the ninth embodiment of the present invention.
FIG. 24 is a sectional view showing the structure of the ninth embodiment of the present invention.
FIG. 25 is a plan view showing the configuration of the tenth embodiment of the present invention.
FIG. 26 is a circuit diagram showing an equivalent circuit of the tenth embodiment of the present invention.
FIG. 27 is a schematic diagram showing the operation of the tenth embodiment of the present invention.
FIG. 28 is a sectional view showing the structure of the tenth embodiment of the present invention.
FIG. 29 is a cross-sectional view showing another configuration of the tenth embodiment of the present invention.
FIG. 30 is a plan view showing the configuration of the eleventh embodiment of the present invention.
FIG. 31 is a circuit diagram showing an equivalent circuit of an eleventh embodiment of the present invention.
FIG. 32 is a sectional view showing the structure of the eleventh embodiment of the present invention.
FIG. 33 is a sectional view showing another structure of the eleventh embodiment of the present invention.
[Explanation of symbols]
S11-S55, D_ij  Photodetector, X1-X5 column scan line, Y1-Y5 row scan line, FL_ij(I = 1-5, j = 1-5) Optical filter, SH_ij  Light shielding film, Fa_ij  First pixel electrode, Fb_ij  Second pixel electrode, Ga_ij  Row scanning line for liquid crystal display, Gb_ij  Column scanning line for liquid crystal display, LC liquid crystal, N_ij  Nonlinear element, Q_ij, T_ij  Transistor, S_i, S_{i + 1}  Source line, G_j, G_{j + 1}  Gate line, DET light detection grid, E_ij  Pixel electrode, 106 Blue transmission light filter, 107 Red transmission light filter, 108 Green transmission light filter, 700 Light pen, 703 Light shielding pen.

Claims (6)

A plurality of first scan lines;
A plurality of second scan lines intersecting each of the first scan lines;
A liquid crystal display element provided near the intersection of the first scanning line and the second scanning line, and connected between the first scanning line and the second scanning line forming the intersection ;
A light detection digitizing method for a liquid crystal display panel comprising:
A series connection body of a photodetecting element and a transistor connected between the adjacent first scanning lines;
A control electrode of the transistor is connected to the second scan line;
When the second scanning line is activated, a signal is input from one of the first scanning lines to the serial connection body, and a signal is detected from the other adjacent first scanning line. you wherein the light sensing digitizer managing method. The light detection digitizing method according to claim 1, wherein the light detection is performed in a period different from a display period of the liquid crystal display panel . 3. The light according to claim 1, wherein the light detection element has a configuration in which n-type amorphous silicon, i-type amorphous silicon, and n-type amorphous silicon are connected in series. Detection digitizing method . Light sensing digitizing method according to claim 1 or claim 2 wherein the optical sensing element is characterized by having a pn junction. A plurality of first scan lines;
  A plurality of second scan lines intersecting each of the first scan lines;
  A liquid crystal display cell provided near an intersection of the first scan line and the second scan line and connected between the first scan line and the second scan line forming the intersection;
A light detection digitizing method for a liquid crystal display panel comprising:
  Each of the liquid crystal display cells
  A transistor including a gate connected to the first scan line, a first current electrode connected to the second scan line, and a second current electrode, and disposed at a position where light reaches;
  A first pixel electrode connected to the second current electrode of the transistor;
  Liquid crystal,
  A second pixel electrode sandwiching the liquid crystal body together with the first pixel electrode;
Have
  An optical signal that is commonly applied to the second pixel electrode of each of the liquid crystal display cells, and detects a leakage current signal of the transistor having an alternating waveform of the alternating signal from the first and second scanning lines; Detection digitizing method. 6. The light detection digitizing method according to claim 5, wherein the light detection is performed in a period different from a display period of the liquid crystal display panel .

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