JP4893115B2 - Display panel - Google Patents

Description

  The present invention relates to a display panel in which an optical sensor for detecting external light is incorporated, and more particularly to a display panel in which a capacitor capable of accommodating the size of the optical sensor can be disposed on the display panel.

  In recent years, liquid crystal panels are often used as flat display panels not only in information communication equipment but also in general electric equipment. This liquid crystal panel is provided with a backlight or a sidelight (hereinafter collectively referred to as “backlight etc.”) because the display image is difficult to see in a dark place because the liquid crystal is not emitting light. Is turned on when the ambient light is dark to illuminate the display image. However, manual operation requires turning the backlight etc. on and off each time according to the brightness of the outside light, which makes the operation cumbersome and unnecessarily turns on the backlight even when it is bright. In such a case, useless power consumption increases, so that the consumption of a battery such as a mobile phone is accelerated.

  Therefore, in order to solve such a problem, there is a technique for incorporating a photo sensor in the liquid crystal panel, detecting the brightness of outside light by this photo sensor, and controlling on / off of the backlight or the like based on the detection result. It has been developed (for example, see Patent Documents 1 to 3 below).

  For example, a liquid crystal display device described in Patent Document 1 below includes a light detection unit having a photosensor on a substrate of a liquid crystal panel, and a thin film transistor (TFT) is used as the photosensor. The sensor is created at the same time as the TFT used as the switching element of the liquid crystal panel, and the light leakage current of the TFT photosensor is detected, so that the backlight etc. is automatically turned on / off according to the ambient brightness. It is a thing.

  In addition, the liquid crystal display device described in Patent Document 2 below includes an external light illuminance detection sensor and a backlight illuminance detection sensor on a substrate of a liquid crystal panel, and controls the backlight and the like based on the detection results of both sensors. It is. Thin film transistors (TFTs) are used for these optical sensors.

Furthermore, the liquid crystal display device of Patent Document 3 below specifies the location of the light detection unit, and on the same substrate, a light detection unit made of a photoelectric conversion element, a liquid crystal display unit made of a thin film transistor (TFT), and A peripheral drive circuit unit for driving the liquid crystal display unit, a peripheral drive circuit unit is arranged in parallel with one side of the liquid crystal display unit, and a light detection unit is arranged in parallel with the other side of the liquid crystal display unit to drive the peripheral The light detection unit is not affected by heat generated from the circuit unit or the like or high-frequency noise.
JP 2002-131719 A (claims, paragraphs [0010] to [0013], FIG. 1) JP 2000-122575 A (paragraphs [0013] to [0016], FIG. 4) JP 11-84426 A (paragraphs [0019] to [0022], FIG. 1)

  By the way, in the TFT photosensors provided in the liquid crystal panels of Patent Documents 1 to 3 described above, a slight leakage current (dark current) flows in the gate-off region when no light strikes, whereas the light intensity when the light strikes. It has a so-called light leakage characteristic in which a large leakage current flows according to (brightness) (see FIG. 7). A TFT photosensor having such characteristics is used by being incorporated in a photodetection circuit as shown in FIG. 8, for example. 7 is a diagram showing an example of a voltage-current curve of the TFT photosensor, FIG. 8 is a known photodetection circuit diagram using the TFT photosensor, and FIG. 9 shows a case where the brightness is different. It is a figure which shows the voltage-time curve of the both ends of the capacitor | condenser in the circuit diagram shown in FIG.

Photodetection circuit as shown in FIG. 8, the capacitor C is connected in parallel between the drain electrode D _L and the source electrode S _L of the TFT ambient light photosensor, one terminal of the source electrode S _L and capacitor C through the switch SW Te is connected to a reference voltage source Vs, further, the other terminal of the drain electrode D _L and the capacitor C of the TFT ambient light photosensor has a structure which is grounded.

The operation of the light detection circuit, first, in advance by applying a constant reverse bias voltage (e.g. -10 V) to the gate electrode G _L of the TFT ambient light photosensor, and turns on the switch SW constant reference voltage Vs (e.g. + 2V ) Is applied to both ends of the capacitor C, and the switch element SW is turned off after a predetermined time. As a result, a source voltage that decreases with time, that is, a charging voltage is obtained at both ends of the capacitor C as shown in FIG. 9 according to the brightness around the TFT photosensor. Therefore, if the charge voltage across the capacitor C is measured after a predetermined time t ₀ after the switch element SW is turned off, an inversely proportional relationship is established between the voltage and the brightness around the TFT photosensor. The brightness around the TFT photosensor can be detected.

However, the capacitor C connected between the drain electrode D _L and the source electrode S _L of the TFT ambient light photosensor in such photodetector circuit is usually because the parasitic capacitance of the TFT is used, as its capacity is small Become. For this reason, the capacitor capacity corresponding to the size of the TFT photosensor cannot be secured, and the time constant in the discharge characteristics of the capacitor is shortened. With this short time constant, it becomes impossible to detect light in a bright place where the leakage current increases. For this reason, it is necessary to secure a capacitor capacity corresponding to the TFT sensor. However, on the display panel, as shown in the sensor area of Patent Document 3, the area is limited. There is a problem that cannot be done.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to secure a capacitor capacity corresponding to the size of the optical sensor on the display panel, and to reliably detect external light. The object is to provide a display panel with improved performance.

  Another object of the present invention is to provide a display panel in which the capacitor can be easily formed on the display panel.

The above object of the present invention can be achieved by the following configurations. That is, the display panel of the present invention is a color filter substrate, an active matrix substrate that is disposed opposite to the color filter substrate, has a larger size than the color filter substrate, and has an overhanging portion protruding from one side of the color filter substrate, A light detection unit including a plurality of photosensors each including a thin film transistor on the active matrix substrate, and at least one of a source wiring and a drain wiring drawn from the thin film transistor of the light detection unit are electrically connected. And a source line provided from the thin film transistor of the light detection unit between the terminal provided in the extension part and connected to an external circuit, and between the light detection part and the terminal provided in the extension part ; And a capacitor part that forms a capacitor with the drain wiring. In the display panel, the light detection unit is arranged on one side of the active matrix substrate on a side different from the one side, and the plurality of thin film transistors constituting the plurality of photosensors are arranged on one side of the active matrix substrate. It is characterized by being arranged along.

In the display panel, the light detection unit and the capacitor unit are disposed adjacent to one side of the active matrix substrate .

In the display panel, one side of the active matrix substrate is a side facing a side having the overhanging portion, and the capacitor unit is at least one side adjacent to the side where the light detection unit is disposed. It is characterized by being disposed on the adjacent side.

In the above display panel, one of the source wiring and the drain wiring is formed of the same material as the source electrode, and the other is formed of the same material as the gate electrode.

In the above display panel, the capacitor portion is formed by a plurality of split capacitors that can be separated.

In the above display panel, the plurality of divided capacitors are a plurality of island electrodes branched from the drain wiring or source wiring, and the insulating capacitors are stacked at positions facing the island electrodes. It is formed between a source wiring or a drain wiring, and the island-shaped electrode and the drain wiring or the source wiring are formed by connecting pieces that can be contacted and separated.

The display panel according to any one of the above , wherein the display panel is a liquid crystal panel.

In the display panel, the optical sensor is formed simultaneously with a thin film transistor as a switching element in the manufacturing process of the liquid crystal panel.

By providing the above-described configuration, the present invention has the following excellent effects. That is, according to the present invention, by providing a capacitor portion between the source wiring and the drain wiring drawn from the thin film transistor that constitutes the optical sensor, it is possible to secure a capacitor capacity corresponding to the size of the optical sensor, so that external light detection is possible. Can improve the reliability. In particular, light detection in a bright place is ensured.

According to the present invention, by providing the light detection unit and the capacitor unit on one side of the active matrix substrate so as to balance the installation space, for example, the space of the light detection unit is reduced and the capacitor unit is arranged at the reduced position. It becomes possible to set. In addition, since the capacitor portion can be formed without providing a special location, the active matrix substrate can be reduced in size.

According to the present invention, by arranging the photodetecting portion on one side of the active matrix substrate, the size of the photosensor can be increased, that is, a plurality of thin film transistors can be arranged in a line along one side of the active matrix substrate. Stable light detection becomes possible. For example, when a part of the light sensor is blocked by a finger due to the user's unintentional movement, or when the light sensor is momentarily blocked by the influence of the surrounding environment, a plurality of light sensors are Since they are arranged in a line, detection is possible. Further, by providing the capacitor portion by disposing the source wiring and the drain wiring on at least one adjacent side adjacent to one side of the substrate, a sufficient capacitor capacity corresponding to the size of the photosensor can be secured.

According to the present invention, the source wiring and the drain wiring are connected to the source electrode and the drain electrode of the photosensor, respectively, and the wirings overlap with each other via the insulating film to form a capacitor as a capacitor. One wiring, for example, the source wiring, is formed in the same process using the same material as the source electrode, and the other wiring, for example, the drain wiring, is formed in the same process using the same material as the gate electrode. If this is done, it is necessary to connect the drain wiring and the drain electrode, but there is no need to provide a separate process for providing the source wiring and the drain wiring in the manufacturing process, and the increase in the number of processes can be minimized. In addition, since the gate electrode is usually covered with a gate insulating film, a capacitor can be easily formed with this configuration. Rukoto can.

According to the present invention, by dividing the capacitor portion formed of the capacitor formed of the source wiring and the drain wiring into a plurality of divided capacitors, the remaining divided capacitors are, for example, one electrode, leaving the required number of divided capacitors. Since it can be easily eliminated by electrically disconnecting the capacitor, the capacitor capacity can be easily adjusted.

According to the present invention, by forming the plurality of divided capacitors by the island-like electrode branched from the drain wiring or the source wiring and the source wiring or the drain wiring, the same effect as the effect shown in claim 5 can be obtained. This island-shaped electrode is connected to the drain wiring or source wiring via a connection piece that can be freely connected to and separated from the drain wiring. Therefore, it is easier to adjust the capacitor capacity by electrically disconnecting this connection piece. It can be carried out.

According to the present invention, it is possible to form a liquid crystal panel that exhibits the same effect as described above .

According to the present invention, the TFT optical sensor can be manufactured at the same time when the thin film transistor as the switching element of the liquid crystal panel is manufactured, so that it is not necessary to increase the number of manufacturing steps particularly in order to provide the optical sensor.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. However, the embodiments described below exemplify a liquid crystal panel as a display panel for embodying the technical idea of the present invention. However, the present invention is not intended to be specified in this embodiment, and the present invention is equally applicable to various modifications without departing from the technical concept shown in the claims. It can be applied.

FIG. 1 is a plan view schematically showing a TFT substrate seen through a color filter substrate of a liquid crystal panel according to Embodiment 1 of the present invention.
As shown in FIG. 1, the liquid crystal panel 1 of the present invention includes a pair of active matrix substrates (hereinafter referred to as TFT substrates) 2 and a color filter substrate CF made of a rectangular transparent material, for example, a glass plate, arranged to face each other. The TFT substrate 2 is larger in size than the color filter substrate CF so that the protruding portion 2a is formed when the TFT substrate 2 is arranged opposite to the color filter substrate CF. The TFT substrate 2 and the color filter substrate CF are used. The outer periphery is attached with a sealing material, and the liquid crystal and the spacer are sealed inside.

  Various wirings and the like are formed on the opposing surface side on the TFT substrate 2 and the color filter substrate CF. Among these, the color filter substrate CF includes a black matrix provided in a matrix in accordance with the pixel region of the TFT substrate 2 and, for example, red (R) and green (G) provided in a region surrounded by the black matrix. And a color filter (not shown) such as blue (B), and a common electrode that is electrically connected to the electrode on the TFT substrate 2 side so as to cover the color filter.

  The TFT substrate 2 has an extended portion 2a on one of the opposing short sides, and a semiconductor chip Dr for a source driver and a gate driver is mounted on the extended portion 2a. The detection unit LS and the capacitor unit CX are disposed adjacent to each other. The light detection unit LS and the capacitor unit CX form a light detection unit LS provided along a short side on a part of the short side, and on a short side excluding a part provided with the light detection unit LS. A capacitor portion CX is formed. In addition, a source line L connected to the light detection unit LS and the capacitor unit CX is disposed on one of the long sides, and the source line L is connected to an external circuit (not shown) via a terminal T. It has become.

Further, the TFT substrate 2 has a plurality of gate lines GW _{1 to} GW _n (n = n =) arranged on the surface thereof, that is, the surface in contact with the liquid crystal with a predetermined interval in the row direction (lateral direction) in FIG. 2, 3, 4,...) And a plurality of source lines SW _{1 to} SW _n insulated from these gate lines and arranged in the column direction (vertical direction), and these source lines SW ₁ to SW _n SW _n and the gate lines _GW 1 _{~GW n} are wired in a matrix, each region surrounded by the gate lines _GW 1 _{~GW n} and the source line _SW 1 to SW _n which cross each other, the gate lines _GW 1 ~ A switching element <not shown> that is on / off controlled by a scanning signal from GW _n and a pixel electrode to which video signals from source lines SW _{1 to} SW _n are supplied via the switching element are formed.

Each region surrounded by the gate lines GW _{1 to} GW _n and the source lines SW _{1 to} SW _n constitutes a so-called pixel, and an area where these pixels are formed becomes a display region DA, that is, an image display unit. ing. For example, a thin film transistor (TFT) is used as the switching element. Each of the gate lines GW _{1 to} GW _n and each of the source lines SW _{1 to} SW _n is extended outside the display area DA and routed to an outer peripheral area outside the display area DA to be used for the source driver and the gate driver. It is connected to the semiconductor chip Dr.

  Next, the light detection unit LS and the capacitor unit CX will be described with reference to FIGS. 2 is an equivalent circuit diagram of the light detection unit LS and the capacitor unit CX, FIG. 3A is a cross-sectional structure diagram of the light detection unit LS, and FIG. 3B is a cross-sectional structure diagram of the capacitor unit CX. .

As shown in FIG. 2, the circuit configuration of the light detection unit LS and the capacitance unit CX includes a plurality of TFT photosensors LS _{1 to} LS _n and capacitors CX ₁ to CX _n constituting the capacitance unit CX. the source electrodes _S L1 _{to S Ln} of each TFT ambient light sensor is connected by a source line L and via the switch SW ₁ constant voltage Vs (e.g. + 2V) is applied to one another, each of the gate electrodes _G L1 _{~G Ln} is Are connected to each other, a constant reverse bias voltage (for example, −10 V) is applied, and the drain electrodes D _{L1 to} D _Ln are connected to each other by the drain wiring L ′ and have the same VCOM as the common electrode of the color filter substrate CF. It has a configuration to be applied. The source of the TFT ambient light sensor _LS 1 _{~LS n} - capacitor _C 1 -C _n between the drain electrode is a parasitic capacitance of each TFT ambient light sensor _LS 1 _{~LS n.} Between the source electrode _S L1 _{to S Ln} and the drain electrode _D L1 _{to D Ln} TFT ambient light sensor _LS 1 _{~LS n,} 1 single or a plurality capacitors _CX 1 _{~CX n} it is connected. Although the drain wiring L ′ is connected to the common electrode of the color filter substrate CF, the drain wiring L ′ may be connected to an external circuit via the terminal T.

The above-described light detection unit LS and capacitor unit CX according to the first embodiment are collectively formed on one short side of the TFT substrate 2. Of these, the TFT photosensors LS _{1 to} LS _n are formed by _first forming gate electrodes G _{L1 to} G _{Ln on} the surface of the TFT substrate 2 and covering these surfaces as shown in FIG. A gate insulating film 3 made of silicon oxide or the like is laminated, and a semiconductor layer 4L made of amorphous silicon, polycrystalline silicon, or the like is disposed on each of the gate electrodes G _{L1 to} G _Ln via the gate insulating film 3. _{1 ~4L n} is formed. Further, on the gate insulating film 3 is provided as the source electrode _S L1 _{to S Ln} and the drain electrode _D L1 _{to D Ln} made of aluminum or metal such as molybdenum is in contact with the respective semiconductor layers _4L 1 _{~4L n.} Then, the protective insulating film 5 made of, for example, an inorganic insulating material is laminated so as to cover the surface of these laminated bodies, so that the TFT photosensors LS _{1 to} LS _n are formed. These TFT photosensors LS _{1 to} LS _n are preferably formed simultaneously with TFTs as switching elements in the manufacturing process of the liquid crystal panel. Thereby, it is not necessary to increase the number of manufacturing steps in particular in order to provide the TFT photosensors LS _{1 to} LS _n .

As shown in FIG. 3, the capacitor CX is formed by forming one terminal of the capacitor CX on the TFT substrate 2 and covering the surface thereof with a gate insulating film made of silicon nitride, silicon oxide, or the like. 3 is laminated, and the other terminal of the capacitor CX made of a metal such as aluminum or molybdenum is formed on the gate insulating film 3. The other terminal is covered with a protective insulating film 5 made of, for example, an inorganic insulating material. Incidentally, one terminal above consists source line L formed integrally with the source electrode _S L1 _{to S Ln} of each TFT ambient light sensor _LS 1 _{~LS n,} the other terminal of each TFT ambient light sensor _LS 1 _{~LS n} The drain wiring L ′ is formed in the same process as the gate electrodes G _{L1 to} G _Ln and is connected to the drain electrodes D _{L1 to} D _Ln .

Additionally, the these TFT ambient light photosensors LS ₁ ~LS _n and the source wiring L from the capacitor unit CX is derived, the wiring is connected to an external circuit via the terminal T is arranged on one long side of the TFT substrate 2 The

Thus when performing optical detection by forming light detecting section LS and the capacitance section CX, constant reverse bias voltage to the gate electrode _G L1 _{~G Ln} of each TFT ambient light sensor _LS 1 _{~LS n} (e.g. -10V ), The switch element SW is turned on, a constant reference voltage Vs (for example, +2 V) is applied to both ends of the capacitors CX _{1 to} CX _n of the capacitor CX, and the switch element SW is turned off after a predetermined time. To do. Accordingly, since the leakage current is generated according to the brightness around each TFT ambient light sensor _LS 1 _{~LS n,} the voltage charged in the capacitor _CX 1 _{~CX n} decreases. The ambient brightness is detected by reading the voltages of the capacitors CX _{1 to} CX _n .

According to this configuration, by combining the light detection unit LS and the capacitor unit CX on the short side of the TFT substrate 2, for example, if the space of the light detection unit LS is reduced without increasing the substrate, the remaining space is transferred to the capacitor unit. Can be used as CX. In addition, since a plurality of TFT light sensors LS _{1 to} LS _n can be arranged in a line, even _{if the} user inadvertently blocks some TFT light sensors with a finger or the like, all the TFT light sensors Since the sensors are unlikely to be blocked at the same time, it is possible to detect light with a TFT light sensor that is not shielded.

  FIG. 4 is a plan view schematically showing a TFT substrate seen through a color filter substrate of a liquid crystal panel according to Embodiment 2 of the present invention. The liquid crystal panel 1A is different from the liquid crystal panel 1 of the first embodiment in that the light detection unit LS is provided over the entire short side of the TFT substrate 2, and the capacitor unit CX is provided on the long side where the source wiring L is provided. Only the configuration is different. Therefore, the same reference numerals are given to the same components as those in the first embodiment, and a duplicate description will be omitted, and only different components will be described below.

  The liquid crystal panel 1A has a configuration in which the light detection unit LS is provided on the short side of the TFT substrate 2 and the capacitor unit CX is provided on one long side. According to this configuration, since all the short sides of the TFT substrate 2 can be used as the light detection unit LS, a large number of TFT photosensors can be arranged, and the size of the light detection unit LS can be increased. In addition, since the capacitor of the capacitance unit CX is formed on the long side, a capacitance corresponding to the size of the light detection unit LS can be easily provided. The capacitor constituting the capacitor CX is preferably formed by pulling out the source wiring L and the drain wiring L ′ on the long side from the light detection unit LS provided on the short side and overlapping the wirings on the long side. . In this manner, the space can be effectively used by forming the capacitor portion CX by pulling out both wirings to the long side portion.

FIG. 5 is a plan view illustrating a liquid crystal panel according to Embodiment 3 of the present invention so that the wiring of the lower TFT substrate can be seen through the color filter substrate laminated on the TFT substrate, and FIG. FIG. 6A is an enlarged plan view in which the portion X in FIG. 5 is enlarged, and FIG. 6B is an AA cross-sectional view in FIG. This liquid crystal panel 1B is different from the liquid crystal panel 1A of the second embodiment in that the capacitor CX is composed of a plurality of divided capacitors CX _{1 to} CX _n . Therefore, the same reference numerals are given to the same components as those in the second embodiment, and a duplicate description will be omitted, and only different components will be described below.

The liquid crystal panel 1B has a configuration in which a light detection unit LS is provided on the short side of the TFT substrate 2 and a capacitance unit CX including a plurality of divided capacitors CX _{1 to} CXn is provided on the long side. The plurality of divided capacitors CX _{1 to} CX _n are formed by a source line L disposed along the long side and a drain line L ′ extending substantially parallel to the source line L. Specifically, the drain wiring L ′ is formed on the TFT substrate 2 along the source wiring L, and a plurality of island electrodes 7 having a predetermined area are extended from one side of the drain wiring L ′. The island-shaped electrode 7 and the common wiring 6 are connected by a connection piece 8. The island-shaped electrode 7 and the common wiring 6 are covered with the gate insulating film 3, and the source wiring L is formed on the gate insulating film 3. Is formed so as to overlap the island-like electrode 7. In the process of creating the divided capacitors CX _{1 to} CX _n , when it is desired to reduce the capacitor capacity of the capacitor CX, the unnecessary connection pieces 8 of the divided capacitors CX _{1 to} CX _n may be cut with a laser cutter or the like. In the third embodiment, the island electrode 7 and the connection piece 8 are provided on the drain wiring L ′. However, the island electrode 7 and the connection piece 8 may be provided on the source wiring L.

FIG. 1 is a plan view schematically showing a TFT substrate seen through a color filter substrate of a liquid crystal panel according to Embodiment 1 of the present invention. FIG. 2 is an equivalent circuit diagram of the light detection unit and the capacitor unit. FIG. 3 is a cross-sectional structure diagram of a TFT photosensor and a capacitor part constituting the light detection part. FIG. 4 is a plan view schematically showing a TFT substrate seen through a color filter substrate of a liquid crystal panel according to Embodiment 2 of the present invention. FIG. 5 is a plan view schematically showing a TFT substrate seen through a color filter substrate of a liquid crystal panel according to Embodiment 3 of the present invention. 6A is an enlarged plan view of the portion X in FIG. 5, and FIG. 6B is a cross-sectional view taken along line AA in FIG. 6A. FIG. 7 is a diagram showing an example of a voltage-current curve of the TFT photosensor. FIG. 8 is a known photodetection circuit diagram using a TFT photosensor. FIG. 9 is a diagram showing a voltage-time curve across the capacitor in the circuit diagram shown in FIG. 8 when the brightness is different.

Explanation of symbols

1, 1A, 1B liquid crystal panel 2 active matrix substrate 2a projecting portion 3 gate insulating film 5 protective insulating film 6 common line 7 island electrode 8 connected piece L source wiring L 'drain wiring LS light detecting section _LS 1 _~LS n TFT light Sensors S _{L1 to} S _Ln Source electrodes G _{L1 to} G _Ln Gate electrodes D _{L1 to} D _Ln Drain electrodes CX Capacitors CX _{1 to} CX _n (divided) capacitors

Claims (8)

A color filter substrate;
An active matrix substrate disposed opposite to the color filter substrate, having a larger size than the color filter substrate, and having an overhanging portion protruding from one side of the color filter substrate;
On the active matrix substrate, a light detection unit including a plurality of light sensors configured to include thin film transistors;
A terminal that is electrically connected to at least one of a source wiring and a drain wiring drawn from the thin film transistor of the light detection unit and is provided in the overhanging unit and connected to an external circuit;
Between the light detection unit and the terminal provided in the projecting portion, a capacitance unit that forms a capacitance between the source wiring and the drain wiring drawn from the thin film transistor of the light detection unit,
In a display panel comprising:
The photodetecting portion is disposed on one side of the active matrix substrate on a side different from the one side, and a plurality of the thin film transistors constituting the plurality of photosensors are arranged along one side of the active matrix substrate. A display panel characterized by being installed.   The display panel according to claim 1, wherein the light detection unit and the capacitor unit are disposed adjacent to one side of the active matrix substrate.   One side of the active matrix substrate is a side facing the side having the overhanging portion, and the capacitor portion is disposed on at least one adjacent side adjacent to the side on which the light detection unit is disposed. The display panel according to claim 1.   2. The display panel according to claim 1, wherein one of the source wiring and the drain wiring is formed of the same material as the source electrode, and the other is formed of the same material as the gate electrode.   The display panel according to claim 1, wherein the capacitor is formed of a plurality of split capacitors that can be separated.   The plurality of divided capacitors include a plurality of island-shaped electrodes branched from the drain wiring or source wiring, and the source wiring or drain wiring stacked via an insulating layer at a position facing the island-shaped electrodes. The display panel according to claim 5, wherein the island-shaped electrode and the drain wiring or source wiring are formed by connecting pieces that can be contacted and separated.   The display panel according to claim 1, wherein the display panel is a liquid crystal panel.   The display panel according to claim 7, wherein the photosensor is formed simultaneously with a thin film transistor as a switching element in a manufacturing process of the liquid crystal panel.

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