JPS60195519A - Display device provided with face input function - Google Patents

Abstract

PURPOSE:To form a switching element and an input element by the same process by forming a diode being the switching element and a photosensitive element being the input element, on a display panel, realizing a high density of a display, and constituting the photosensitive element, too, of the diode. CONSTITUTION:A liquid crystal layer 83 is inserted and held between the first substrate 82 and the second substrate 81, and an area which functions as a display element becomes a liquid crystal layer 97 of a part where a data line D and a display electrode DE are superposed. An area which functions as an accumulation capacity CS is formed on a part where the second scanning line S* by the second metallic layer and an accumulation electrode 51 by the first metallic layer are superposed by placing a layer insulating layer 86 between them. Diodes D1-D3 are formed in an area where a semiconductor layer 96 is placed between two metallic layers of the first and the second layers. A photosensitive element PD has a photodiode constitution, and it is formed by placing a semiconductor layer 87 between a transparent electrode layer 88 and the second scanning line S* being the second metallic layer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is an active matrix type display panel having a switching element in each pixel, and a display device with a surface input function that allows information to be input from the panel surface using a light pen or the like. Regarding.

[Background of the invention]

Flat display panels using liquid crystals and the like are widely used, and in recent years, high-density display panels of the so-called active matrix type in which each pixel is provided with a switching element have been developed. Thin film transistors (T
Three-terminal types such as PT) and two-terminal types such as diodes and nonlinear resistance elements (NLR) are used, and the two-terminal type is particularly promising because it is easy to manufacture and has stable characteristics.

In contrast to the progress of display devices as output devices, keyboards are mainly used as input devices. However, some methods have been developed in which input and output are integrated and input is performed from the display screen. A typical example is the cathode ray tube (CR).
A method (light pen method) in which the light emitted from a light-emitting type display such as T) is picked up by a light-receiving element (commonly known as a light pen) and the position is specified from the timing of the light emission (light pen method). There are methods such as measuring with a gauge and specifying the position (strain method).

In particular, flat panels have a small volume, so integrating the input and output is attractive because it takes advantage of this advantage.

[Prior art and problems]

Taking liquid crystals as an example, the light pen method cannot be used because they are non-emissive. Although the distortion method is fully possible, its disadvantages are that the resolution is low and it is separate from the panel.

Since the display is becoming more dense, it is preferable that the input resolution be high enough to match this.

[Object of the Invention] An object of the present invention is to realize a display panel with an input function capable of high-resolution surface input using a simple manufacturing method.

[Structure of the invention]

In the present invention, a diode as a switching element and a photosensitive element as an input element are formed in a display panel-1-, thereby achieving high display density and light. At the same time, it is possible to increase information and human power. By also configuring the photosensitive element with a diode, the switching element and the human element can be formed in the same process. The following will explain based on the drawings.

[Embodiments of the invention]

Before explaining the present invention in detail, first, an active matrix display device using diodes without an input function will be briefly explained. Fig. 1 is a block diagram of the display device, and Fig. 2 is the unit II! ii cumulative configuration display panel,
FIG. 3 is an example of a drive waveform. Figure i1 "'C" 1 is the scanning line 5(1), 5(2)...s(l'IJl
The data line D(1), D(2), J)fM, scanning line, and unit pixel shown in FIG. 2 are provided at each intersection of the data line. In the unit pixel, a nonlinear resistor NL consisting of diodes D1 and D2 connected in parallel and opposite directions to the liquid crystal display element Lc is connected in series between the scanning line S and the data line. 2
is a data line driver that supplies data signals to the data line,
6 is a scanning line driver that supplies scanning signals to the scanning lines; 4 is a video processing circuit that supplies video signals to the data line driver; and 5 is a clock circuit that supplies timing pulses to each driver.

The above configuration was previously applied for (Patent Application No. 57-167944.16)
7945). In FIG. 3, φfI) is a scanning signal supplied to the I-th scanning line, and ψ(J) is a data signal supplied to the J-th data line. Scanning signal φ(I
l has selection phases t6, t*, and retention phases 1L, 1*L, with selection phases 1. , I* have a selection potential of 8 above, and holding phases IL, , l*L have a holding potential of ±Vb. The data signal ψU) takes the potential between the data potential terminals d according to the data content. Details of such a drive method with holding phase are described in a previous application (Japanese Patent Application No. 167,943/1982). The active matrix using the above diodes is 'I'
It is easier to manufacture than the FT type, has stable device characteristics, and is extremely promising as a large-area, high-density flat display panel.

FIG. 4 is a block diagram of an embodiment of the present invention, and FIG. 5 is a unit pixel configuration. 6 is a display panel, and the difference from FIG. ...S
” (Photosensitive element-7P I at the point where Ll is located and the unit pixel)
, storage capacity, and output diode D6 are formed.

7 is an output data processing circuit; 8 is a second scanning line driver;
9 is a slam memory.

FIG. 6 is an example of the drive waveform of the present invention, and shows the photosensitive element P.
A method for detecting a change in the characteristics of D is shown. φ＊(■)
is the first second scanning line S* (the second
This is a scanning signal that is selected line-sequentially at regular intervals. The fifth data output line D"tJ) is connected to a constant potential as ψ through J). ε.8 is the potential at location 51 of the pixel where the photosensitive element PD is irradiated with light, and TONfJ+ is This is the ?Ii style that is released in the data output line (, ■).

The voltage 61 accumulated in the storage capacitor ics in the selection phase 60 is discharged by photovoltaic current caused by light irradiation in the holding phase 62.

Therefore, in the next discharge phase 66, the output diode D is connected again.
A charge such as 64 is released through 3. On the other hand, ε. , P
is the potential at 51 locations of the pixel that is not irradiated with light, ■. ,
, (J) is the current discharged to the data output line DnefJ+. Since no current due to light flows in the holding phase 65, no current flows in the selection phase 66 either. In this embodiment, as described above, the current (2) flows through each data output line. , (J
l, ■. By measuring ryal, it is possible to detect light-irradiated pixels.

FIG. 7 shows an output data processing circuit 7 in an embodiment of the present invention.
This is an example. Each data output line DI(11, D*(2)
, . . . Prisoner D is connected to zero potential 72 via a resistor 71. The potential across the resistor 710 corresponds to the current flowing to each data output line, and the potential across the resistor 710 corresponds to the current flowing through the latch 7 through the amplifier 76.
4 by the latch signal 76. The latch output is manually inputted to a shift register 75, converted into parallel/norial signals according to the clock input cuff 7, and inputted to the button memory 9 as a serial signal 78. The input buttons stored in the memory are manually input to the video processing circuit 4 and displayed on the display panel as necessary.

FIG. 8 shows the actual pattern of the unit pixel with the configuration shown in FIG. 5, and FIG. Shown below. Figure 8(b), (
In c), a data line and an alignment layer 85 are formed on the first substrate 82.

On the second substrate 81, a lower electrode 91 of the display electrode DE diode, lower wiring layers 9o and 93, and a lower electrode 88 of the photosensitive element are formed by a transparent electrode layer, and a first layer of Cr, Ni, etc.
The lower layer electrode 92 of the diode and the upper wiring layer 89 are formed by the metal layer.
．． 94, the storage electrode 51 is formed, and the diode layer 9 is formed by the amorphous silicon (A-8I) pin semiconductor layer.
6 and a photosensitive layer 87 are formed, and a glabella insulating layer 86 is formed of an insulating layer such as 8.02, SiN, etc.
Interconnection 9 is formed by a second metal layer such as Ni, Ag, At+, etc.
5 and scanning lines S and S* are formed, and an alignment treatment layer 84 for the -hK liquid crystal is formed thereon. A liquid crystal layer 86 is sandwiched between the first substrate 82 and the second substrate 810.

The area that functions as a display element is the data line and display electrode DE.
The overlapping portion becomes the liquid crystal layer 97. Storage capacity C8
The region functioning as the second scanning line S* made of the second metal layer and the storage electrode 51 made of the first metal layer overlap with each other with the interlayer insulating layer 86 in between. Diodes D1, D2, and D6 divide the semiconductor layer 96 into first and second two
Formed in the area between the metal layers of the layer. Photosensitive element PD
has a photodiode configuration, and has a transparent electrode layer 88 and a second
A semiconductor layer 87 is formed sandwiched between the second scanning line S, which is a metal layer.

One special feature of this embodiment is that the diode layer and the photosensitive layer are formed in the same process. However, if they have the same structure, the diode becomes sensitive to light, and specifically, leakage current due to light increases and switching characteristics deteriorate. Therefore, in this embodiment, light leakage is reduced by placing metal layers on the top and bottom of the diode as contact electrodes that also function as a light shield, and for the photosensitive element, one of the contact electrodes is made of a transparent electrode layer. Maintains photosensitivity to directional light. By adopting the configuration of this embodiment, it is possible to form photosensitive elements and diodes on the display panel without increasing the number of steps.

The number of photomasks used in this example is one for the first substrate and five for the second substrate.
Compared to the total of 7 to 9 PT panels, the number is sufficiently small, low cost, high yield, and easy to increase the area (C).

In the present invention, a photosensitive element is formed in each pixel as described above, and changes in characteristics are read in response to the presence or absence of light irradiation.

have the means to issue it. Therefore, it is possible to input arbitrary figures, characters, etc. using a small pencil type light as shown in FIG. 9, for example. In FIG. 9, 101 is a light emitting diode, 102 is a reflector, 106 is a switch, and 104 is an AAA, AAA, or (J button/type) battery.

In the embodiment, a photosensitive element may be formed in each pixel, and a photosensitive element may be formed every few pixels or only in a partial area of the entire screen.

The diode is used as a diode ring type nonlinear element connected in parallel and in reverse directions as shown in Figs. 2 and 5, but the diode switch type disclosed in U.S. Pat. Good too. Furthermore, the present invention is of course effective even when using display elements such as electrochromism and electroluminescence in addition to liquid crystal.

1 Effects of the Invention As stated above, the present invention can be manufactured in almost the same process as a conventional active matrix display panel, and it is possible to display high-resolution figures, characters, etc. from the display panel surface. Provides a display device with a 100-manpower function that allows input.
It is effective for a wide range of purposes, including personal electronic memos.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional display device that has a surface input function using diodes, Fig. 2 is a unit pixel configuration diagram of a conventional display device, and Fig. 3 is a drive waveform diagram of a conventional display device. , FIG. 4, FIG. 5, and FIG. 6 are block diagrams, unit pixel configuration diagrams, and drive waveform diagrams of a display device having a surface input function according to the present invention, and FIG. 7 is a block diagram of its output data processing circuit. Figure 8 shows a unit pixel corresponding to the configuration of Figure 5,
FIG. 8(a) is a plan view, FIGS. 8(b) and 8(c) are cross-sectional views, and FIG. 9 is a cross-sectional view of an example of a probe used for optical input. 1.6... Display panel, 2... Data line driver, 6
・Scanning line driver, 7 ・Output data processing circuit,
S, 5(11~5(Nl scanning line ri, D(11~DH・
... Data line, Dl, D2, D6 ・Diode, l (' ...Liquid crystal display element, PD... Likelihood sensing element r. Fig. 1 Fig. 2 Fig. 31 Fig. 4 Fig. 5 Fig. 1 ON (J) ~L------Le Figure 7 Figure 9

Claims (1)

[Scope of claims] A display device with a surface input function, characterized in that a photosensitive element is formed and has means for detecting a change in the characteristics of the photosensitive element. (2) The photosensitive element is characterized in that it is composed of a diode. A display device with a surface input function according to claim 1. (3) A diode for addressing a display element and a diode serving as a photosensitive element are formed on a display panel in the same process. A display device with a surface input function according to claim 1. (4) At least one electrode of the diode that addresses the display element is formed of a metal layer, and at least one electrode of the diode that serves as a photosensitive element 2. A display device with a surface input function according to claim 1, wherein the display device is formed of a transparent conductive layer.