JP4019477B2 - Display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display device, and more particularly to a line sensor for image recognition and a display device having a print function.
[0002]
[Prior art]
In recent years, portable information devices such as notebook computers and mobile computers equipped with thin display devices such as liquid crystal display elements have been developed. Such portable information devices do not have an image capturing function by themselves, and it is necessary to use a digital camera or a handy image reader in order to capture an image.
[0003]
Some desktop word processors incorporate a thermal printer having a thermal head and an image reader separately from the display device.
[0004]
[Problems to be solved by the invention]
However, with conventional portable information devices, for example, in order to read a document on which a printed matter such as a map or a handwritten figure is read with a digital camera, it cannot be read neatly unless a jig for fixing the camera is used. there were. Further, the handy image reader is not small enough to be used as a peripheral device of a portable information device, and hinders portability.
[0005]
In addition, conventional desktop word processors have a problem in that the size of the device is increased by incorporating a thermal printer or an image reader.
[0006]
In view of these circumstances, an object of the present invention is to provide a lightweight and compact display device having an image reader function and a printer function.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a display device,
A transparent substrate after the display area, the thermal head portion forming region, the line sensor unit forming regions are arranged respectively separately,
Before the transparent substrates bonded only in the display area of the rear transparent substrate a sealing material is interposed,
Liquid crystal sealed between the rear transparent substrate and the front transparent substrate;
An amorphous silicon film deposited in the display region on the rear transparent substrate, the thermal head portion forming region, and the line sensor portion forming region;
A thin film transistor having a semiconductor layer formed by patterning the amorphous silicon film provided in the display region on the rear transparent substrate;
A thermal head having a resistance heating element layer formed by annealing and then patterning the amorphous silicon film deposited in the thermal head portion forming region ;
A line sensor having a semiconductor layer formed by patterning the amorphous silicon film formed on the line sensor portion forming region on the rear transparent substrate,
A backlight that is arranged behind the rear transparent substrate and emits light for recognizing the line sensor and light for liquid crystal display in the display area;
It is characterized by having.
[0008]
In the first aspect of the invention, since the line sensor is formed on the substrate of the display device, it is possible to achieve a more compact size than a configuration in which an image reader is separately incorporated.
[0009]
According to a second aspect of the present invention, in the display device according to the first aspect, the line sensor is configured such that a MOS photosensor is arranged on a surface side of the rear transparent substrate on which the thin film transistor is formed. The display device according to claim 1.
[0010]
In the second aspect of the invention, the MOS type photosensor can be produced by using a manufacturing process of a thin film transistor formed on the same surface side of the transparent substrate after the liquid crystal cell is formed. A simple and compact line sensor can be manufactured without requiring a simple manufacturing process. Thus, in the invention according to claim 2, the structure can be made compact and the weight can be reduced.
[0011]
According to a third aspect of the present invention, in the display device according to the second aspect, the line sensor includes a bottom gate electrode having a light shielding property formed on the substrate side, and a bottom gate insulating film on the bottom gate electrode. A semiconductor layer formed through the semiconductor layer, source / drain electrodes connected to both sides of the semiconductor layer, and a transparent top gate electrode formed on the semiconductor layer through a top gate insulating film. It is characterized by that.
[0012]
In the third aspect of the invention, when the light passes through the transparent top gate electrode and enters the semiconductor layer, the state of carriers in the semiconductor layer changes according to the physical quantity of incident light, and the source electrode changes according to the carrier state. The amount of current flowing between the drain electrode and the drain electrode is determined, and brightness can be detected according to this value. Here, the sense state of the line sensor can be controlled by controlling the voltage applied to the top gate electrode. Further, by controlling the voltage applied to the bottom gate electrode, it is possible to control the selection and non-selection states of the sensor. In the present invention, since the bottom gate electrode has a light shielding property, it is possible to prevent the light from directly entering the semiconductor layer and causing malfunction even when the recognition light is irradiated from behind the substrate.
[0017]
A fourth aspect of the present invention is the display device according to any one of the first to fourth aspects, further comprising traveling means for causing the recognized sheet to travel with respect to the line sensor.
[0018]
In the invention according to the fourth aspect , the image can be read by running the recognized sheet such as a map or a handwritten drawing along the line sensor by the running means.
[0019]
Fifth aspect of the present invention, a display device according to claim 1, wherein said display area and said thermal head are arranged and formed on the rear transparent substrate. Invention according to claim 6, a display device according to claim 1, wherein the thermal head is arranged and formed in the vicinity of the line sensor, the printed sheet is traveling on the thermal head in said traveling means It is characterized by that.
[0020]
According to the fifth aspect of the present invention, since the thermal head is formed on the substrate of the display device, it is possible to achieve a more compact size than a configuration in which a printer is separately provided. In a sixth aspect of the present invention, if the thermal head is composed of a semiconductor layer to be a heat radiating head and a metal electrode connected to the semiconductor layer, the semiconductor layer and the metal electrode are formed by the steps of the switching element of the liquid crystal cell. Since it is common to the forming process, no special manufacturing process is required for forming the thermal head. Further, since the thermal head is integrally formed on the substrate in the same manner as the line sensor, it can be combined with the display device in a compact manner. In the invention described in claim 6, it is possible to perform thermal printing on a printing sheet (paper or the like) using the traveling means. Further, since the thermal head is arranged and formed in the vicinity of the line sensor, the sheet can be fed using the same traveling means, and compactness can be achieved.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the display device according to the present invention will be described based on embodiments shown in the drawings.
[0022]
(Embodiment 1)
1 to 6 show Embodiment 1 of a display device according to the present invention. FIG. 1 is an explanatory side view showing an outline of the present embodiment. In FIG. 1, reference numeral 11 denotes a display device which is used as a display means of a portable information device such as a notebook personal computer or a mobile computer. As shown in the figure, the display device 11 includes a liquid crystal cell 12, a line sensor unit 14, a thermal head unit 13, a backlight system 15, and a paper feeding device 16 as traveling means. The display device 11 further includes a polarizing plate (not shown) disposed on the surface of the liquid crystal cell 12, a casing (not shown) for housing the liquid crystal cell 12, the backlight system 15, and the like. For example, a lower end portion is pivotally supported by the portable information device main body 17 so that the portable information device main body 17 (indicated by a one-dot chain line in the figure) 17 such as a notebook personal computer or a mobile computer can be tilted or stood up.
[0023]
In the liquid crystal cell 12, the front transparent substrate 18 and the rear transparent substrate 19 are bonded together with a sealing material 20 surrounding the liquid crystal display region, and the liquid crystal 21 is formed in a gap formed by both the substrates 18, 19 and the sealing material 20. Is sealed. The rear transparent substrate 19 has a larger area than the front transparent substrate 18, and the lower portion of the rear transparent substrate 19 faces the front transparent substrate 18 as shown in FIG. It is set to be exposed. Although not shown, a color filter, a black mask, a common electrode, a front alignment film, and the like are formed on the rear surface of the front transparent substrate 18 as is well known. Although not shown, a pixel electrode, a thin film transistor (TFT) as a switching element, a rear alignment film, and the like are formed on the front surface of the rear transparent substrate 19. FIG. 2 is a front view showing the front side of the rear transparent substrate 19. Thereafter, as shown in FIG. 2, a thermal head portion 13 and a line sensor portion 14 are formed on the front surface of the exposed portion of the transparent substrate 19 along the width direction of the substrate. The thermal head unit 13 and the line sensor unit 14 are arranged and formed so as to be adjacent and parallel to each other with a very small distance. In FIG. 2, reference numeral 22 denotes a display area in which the liquid crystal 21 is sealed.
[0024]
As shown in FIG. 1, the paper feeding device 16 includes a guide roller 23 </ b> C located in front of the thermal head unit 13 and the line sensor unit 14, and a pair of driving drive pinches provided in the portable information device main body 17. And rollers 23A and 23B. The guide roller 23C is set so as to press the document 24 on which characters or the like are written against the thermal head unit 13 and the line sensor unit 14 with a predetermined pressure. In addition, one of the pinch rollers 23A and 23B is driven to rotate, and the other is pressed against the one pinch roller with a predetermined pressure so as to be driven to rotate. When image recognition is performed using the line sensor unit 14, a document to be recognized is used as the document 24. In addition, when printing is performed using the thermal head unit 13, thermal paper can be used as the document 24, and plain paper can be used when a thermal ribbon is used.
[0025]
Next, the configuration of the line sensor unit 14 will be described with reference to FIG. In the line sensor unit 14, photosensors are arranged in a line in the width direction of the rear transparent substrate 19. The line sensor unit 14 is composed of a bottom gate electrode 25B formed on the front surface of the rear transparent substrate 19, a gate insulating film 26 formed on the bottom gate electrode 25B, and amorphous silicon formed on the gate insulating film 26. The semiconductor layer 27B, the source electrode 33s and the drain electrode 33d formed so as to be connected to the semiconductor layer 27B via the n + layer 31, respectively, and the semiconductor layer 27B, the source / drain electrodes 33s and 33d, and so on. A transparent insulating film 35 as a top gate insulating film formed on the semiconductor layer 27B, and a top gate electrode 36 formed on the transparent insulating film 35 above the semiconductor layer 27B. Note that a transparent protective film 37 is coated on the line sensor unit 14 so as to withstand friction with paper (original) serving as a recognition sheet to be traveled and to maintain electrical insulation. .
[0026]
The operation and operation of the line sensor unit 14 having such a configuration will be described. In the line sensor unit 14, a sense state control unit (not shown) controls the voltage applied to the top gate electrode 36 to control the sense state of the line sensor unit 14, and a selection control unit (not shown) applies to the bottom gate electrode 25B. It is possible to control the selection and non-selection states of the line sensor unit 14 by controlling the voltage to be applied. A sense voltage −20V is applied to the top gate electrode 36 to which the non-sense voltage 0V has been applied, and a sense state is established. Among these, the selection voltage 10V is applied to the bottom gate electrode 25B to which the non-select voltage 0V has been applied. Then, a current flows between the source / drain electrodes 33s and 33d in accordance with the amount of light incident on the semiconductor layer 27B. That is, the current value is determined according to the shadow of characters or the like printed on the document 24, and image data according to this current value is displayed on the liquid crystal cell 12 or printed by the thermal head unit 13.
As described above, the line sensor unit 14 can have both a function as a photo sensor and a function as a selection transistor. For this reason, in this embodiment, since the selection transistor is not separately required, the line sensor unit 14 can be reduced in size. Further, if the sense state control means described above controls the voltage applied to the top gate electrode 36 on the side receiving the recognition light (detection light), the set and reset states of the line sensor unit 14 can also be controlled. Since the charge accumulated in the previous semiconductor layer 27B can be immediately released, it is possible to quickly perform image recognition by continuously detecting light as the document 24 travels. As shown in FIG. 3, the light source for recognition light uses the backlight system 15 used for transmissive liquid crystal display, and the light that has passed through the rear transparent substrate 19 from the rear to the front is the surface of the document 24. The light reflected according to the state passes through the protective film 37, the top gate electrode 36, the transparent insulating film 35, and the blocking layer 29B and is incident on the semiconductor layer 27B, thereby enabling light detection. At this time, since the bottom gate electrode 25B is a light-shielding electrode made of Al, direct light incidence from the backlight system 15 to the semiconductor layer 27B can be prevented, and no malfunction occurs.
[0027]
Next, the configuration of the thermal head unit 13 will be described with reference to FIG. The configuration of the thermal head unit 13 in this embodiment is arranged and formed on the front surface of the rear transparent substrate 19 so as to be arranged in a line in the width direction of the substrate. In this thermal head portion 13, a gate insulating film 26 is formed on the front surface of the rear transparent substrate 19, a resistance heating element layer 27C made of polysilicon, and head electrodes connected to both ends of the resistance heating element layer 27C. 34 and 34 are formed and further covered with a transparent insulating film 35. In this thermal head portion 13, by applying a voltage between the head electrodes 34, 34 sandwiching the resistance heating element layer 27C, the resistance heating element layer 27C is caused to generate heat, and thermal transfer is performed, for example, on thermal paper or plain paper. It becomes possible.
[0028]
By adopting such a configuration, in this embodiment, the line sensor unit 14 and the thermal head unit 13 can be compactly incorporated in the display device 11, and the function of a portable information device including the display device 11 can be improved. Enables weight reduction and thinning. In particular, in this embodiment, since the light of the backlight used for the liquid crystal display can be used as the light for recognition of the line sensor unit 14, a separate light source is not required and a compact configuration is obtained. Thus, in this embodiment, in addition to performing liquid crystal display on the display device 11, it is possible to perform image recognition at the line sensor unit 14 and thermal transfer printing at the thermal head unit 13.
[0029]
Next, a method for manufacturing the display device 11 according to the present embodiment will be described with reference to FIGS. First, as shown in FIG. 4A, an aluminum (Al) film, for example, is deposited on the front surface of a transparent substrate 19 made of glass, and this aluminum film is patterned by using a photolithography technique and an etching technique. A gate electrode 25A of each TFT 39, which will be described later, is formed in the region 22, and a bottom gate electrode 25B of the photosensor is formed in each dot portion of the formation region of the line sensor unit.
[0030]
Then, as shown in FIG. 4B, a gate insulating film 26 made of, for example, silicon nitride (SiNx) or silicon oxide (SiO ₂ ) is deposited on the substantially entire surface so as to have a predetermined thickness. Thereafter, an amorphous silicon film is deposited on the gate insulating film 26, laser annealing is partially performed on the amorphous silicon film in the thermal head portion formation region, patterning is performed using a photolithography technique and an etching technique, and each display area is subjected to patterning. The semiconductor layer 27A of the TFT is formed, the semiconductor layer 27B is formed in the line sensor portion formation region, and the resistance heating element layer 27C is formed in the thermal head portion formation region. Here, the resistance heating element layer 27C formed in the thermal head portion formation region is formed by changing amorphous silicon into polysilicon as a result of the laser annealing described above. The semiconductor layers 27A and 27B remain amorphous silicon because they are not subjected to laser annealing. The gate insulating film 26 in the line sensor portion forming region is referred to as a bottom gate insulating film.
[0031]
Next, as shown in FIG. 5A, a transparent pixel electrode 28 made of ITO (indium tin oxide) is formed in the display area. Then, on each of the semiconductor layers 27A and 27B, transparent blocking layers 29A and 29B made of, for example, silicon nitride are patterned so as to cover the channel region. Further, n ⁺ layers 30 and 30 separated on the blocking layer 29A are formed on the semiconductor layer 27A on which the blocking layer 29A is formed, and on the semiconductor layer 27B on which the blocking layer 29B is formed. Then, n ⁺ layers 31 and 31 separated on the blocking layer 29B are formed, respectively. These n ⁺ layers 30 and 31 are formed by simultaneously patterning an amorphous silicon film into which an n-type impurity is introduced.
[0032]
Thereafter, for example, an Al film is deposited and patterned to form a source electrode 32s, a drain electrode 32d, and a source electrode 33s separated on the blocking layers 29A and 29B as shown in FIG. 5B. The drain electrode 33d and the head electrode 34 connected to both ends of the resistance heating element layer 27C are formed. Note that the source electrode 32 s in the display region 22 is formed so as to be connected to the pixel electrode 28.
[0033]
Next, as shown in FIG. 6, a transparent insulating film 35 made of SiNx, SiO ₂ or the like is deposited on the entire surface so as to have a predetermined film thickness. This transparent insulating film 35 is referred to as a top gate insulating film in the line sensor portion forming region. Then, as shown in FIG. 7, a top gate electrode 36 made of transparent ITO is formed on the transparent insulating film 35 in the line sensor portion formation region so as to be positioned above the semiconductor layer 27B. Further, a transparent protective film 37 is formed on the line sensor portion forming region. Further, a rear alignment film 38 is formed on the display region 22 as shown in FIG. In this way, the configuration (pixel electrode 28, TFT 39, etc.), the thermal head portion 13, and the line sensor portion 14 in the display area 22 of the rear transparent substrate 19 of the liquid crystal cell 12 can be formed.
[0034]
The manufacturing method on the rear transparent substrate 19 side in the present embodiment has been described above. However, the configuration on the front transparent substrate 18 side and the method for manufacturing the liquid crystal cell 12 by bonding the front transparent substrate 18 to the rear transparent substrate 19 are described. Since it is well known, its description is omitted. As described above, in the display device 11 according to the present embodiment, since the display portion, the line sensor unit 14, and the thermal head unit 13 are manufactured on the same glass substrate 19, since there are common steps, there are few steps as a whole. There is an advantage that it can be done with numbers.
[0035]
(Embodiment 2)
8 and 9 show Embodiment 2 of the display device according to the present invention. FIG. 8 is a cross-sectional explanatory view of a main part of the display device 41 of the present embodiment, and FIG. 9 is a perspective view showing a use state of a portable information device 51 such as an electronic notebook, in which the display device 41 is incorporated. In the display device 41 of the present embodiment, as shown in FIG. 8, the line sensor unit 14 is formed on the front side of the lower end of the rear transparent substrate 19 of the liquid crystal cell, and an optical system that conducts light in front of the line sensor unit 14. A prism 42 having a triangular cross section is disposed. In this prism 42, one side surface 42A is bonded along the front surface of the rear transparent substrate 19, and a lower surface 42B adjacent to the one side surface 42A is a traveling surface of a paper (original) 24 as a recognized sheet. . A light source 43 and a condensing mirror 44 that emit and supply recognition light to the line sensor unit 14 are provided along the width direction of the rear transparent substrate 19 on the other side surface 42C side. In the present embodiment, the light source 43 and the condensing mirror 44 only supply light for recognition to the line sensor unit 14, and thus may have a small and thin structure, and the light guide path may be short, so the prism 42. Can be small. The display device 41 in the present embodiment does not include a thermal head unit, but the other configuration is substantially the same as that of the above-described first embodiment, and thus the description thereof is omitted.
[0036]
In the display device 41 according to the present embodiment, the recognition light emitted from the light source 43 is reflected in accordance with the surface state of the document 24 as indicated by a one-dot chain line arrow in FIG. The reflected light is set to enter the line sensor unit 14 at the corresponding position by the prism 42. In the present embodiment, a light-shielding partition wall that prevents the light from leaking in the lateral direction may be provided so that the reflected light from the document 24 does not enter the line sensor unit 14 in the lateral direction. By adopting a simple configuration, it is possible to perform highly accurate image recognition.
[0037]
In such a display device 41 of the present embodiment, as shown in FIG. 9, the lower surface 42 </ b> B of the prism 42 is in close contact with the document 24 by holding the portable information device 51 by hand by being incorporated in the portable information device 51. Thus, it is possible to perform image recognition. In particular, in this embodiment, since the structure of the line sensor unit 14 and the optical system that supplies light for recognition thereto may be extremely small, the display device 41 having an image recognition function can be made compact. For this reason, the portable information device 51 provided with this display device 41 can also be made lightweight and compact.
[0038]
As mentioned above, although Embodiment 1 and Embodiment 2 were demonstrated, this invention is not limited to these, The various change accompanying the summary of a structure is possible. For example, in the first and second embodiments, the display devices 11 and 41 are configured to be incorporated in a portable information device. However, it is of course possible to incorporate the display devices 11 and 41 in a desktop word processor or a personal computer. Can be expected. In the first embodiment, both the line sensor unit 14 and the thermal head unit 13 are provided, but only the line sensor unit 14 may be used. In the second embodiment described above, the thermal head unit is not provided. However, a configuration with a thermal head unit added may be employed. Further, it is possible to adopt a configuration in which only the thermal head unit is provided without the line sensor unit 14. Further, in each of the embodiments described above, the line sensor unit 14 and the thermal head unit 13 are arranged on the rear transparent substrate 19 side, but the lower portion of the front transparent substrate 18 extends downward from the lower portion of the rear transparent substrate 19. The structure may be arranged on the front transparent substrate 18 side. Furthermore, in each of the embodiments described above, the display means in the display area is a liquid crystal display element including the liquid crystal cell 12, but an electroluminescence (EL) display element formed on a transparent substrate and other display means are applied. It is also possible to do. Further, in each of the embodiments described above, the TFT is applied as the switching element in the liquid crystal cell 12, but an MIM element that is a two-terminal switching element may be applied. Even when this MIM element is applied, since there are many common processes between the manufacturing process of the MIM element and the manufacturing process of the line sensor unit 14 and the thermal head unit 13, the display device can be manufactured without greatly increasing the number of processes. It can be manufactured. Further, as the configuration of the line sensor unit 14, various photosensors can be applied in addition to the MOS photosensor.
[0039]
【The invention's effect】
As is apparent from the above description, according to the present invention, a lightweight and compact display device having an image reader function and a printer function can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory side view showing a first embodiment of a display device according to the present invention.
2 is a plan view showing a front surface of a rear transparent substrate in the display device of Embodiment 1. FIG.
3 is a cross-sectional view of a line sensor unit in the display device of Embodiment 1. FIG.
4A and 4B are process cross-sectional views illustrating a method for manufacturing the display device of Embodiment 1. FIG.
5A and 5B are process cross-sectional views illustrating a method for manufacturing the display device of Embodiment 1. FIG.
6 is a process cross-sectional view illustrating the method for manufacturing the display device of Embodiment 1. FIG.
7 is a process cross-sectional view illustrating the method for manufacturing the display device of Embodiment 1. FIG.
FIG. 8 is a cross-sectional view of a main part showing Embodiment 2 of a display device according to the present invention.
FIG. 9 is a perspective view illustrating a usage state of a portable information device in which the display device of Embodiment 2 is incorporated.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Display apparatus 12 Liquid crystal cell 13 Thermal head part 14 Line sensor part 15 Backlight system 16 Paper feeder 17 Portable information apparatus main body 18 Front transparent substrate 19 Rear transparent substrate 21 Liquid crystal 22 Display area 24 Original 25B Bottom gate electrode 26 Gate insulating film 27B Semiconductor layer 33s Source electrode 33d Drain electrode 35 Transparent insulating film 36 Top gate electrode

Claims (6)

After the display area, the thermal head part forming area, and the line sensor part forming area are separately arranged, and a transparent substrate,
Before the transparent substrates bonded only in the display area of the rear transparent substrate a sealing material is interposed,
Liquid crystal sealed between the rear transparent substrate and the front transparent substrate;
An amorphous silicon film deposited in the display region on the rear transparent substrate, the thermal head portion forming region, and the line sensor portion forming region;
A thin film transistor having a semiconductor layer formed by patterning the amorphous silicon film provided in the display region on the rear transparent substrate;
A thermal head having a resistance heating element layer formed by annealing and then patterning the amorphous silicon film deposited in the thermal head portion forming region ;
A line sensor having a semiconductor layer formed by patterning the amorphous silicon film formed on the line sensor portion forming region on the rear transparent substrate,
A backlight that is arranged behind the rear transparent substrate and emits light for recognizing the line sensor and light for liquid crystal display in the display area;
A display device comprising:   The display device according to claim 1, wherein the line sensor includes MOS photosensors arranged on a surface side of the rear transparent substrate on which the thin film transistor is formed.   The line sensor is connected to both sides of the semiconductor layer, a light-shielding bottom gate electrode formed on the substrate side, a semiconductor layer formed on the bottom gate electrode via a bottom gate insulating film, and 3. A display device according to claim 2, further comprising a source / drain electrode and a transparent top gate electrode formed on the semiconductor layer via a top gate insulating film.   The display device according to claim 1, further comprising a traveling unit that causes the recognized sheet to travel with respect to the line sensor.   The display device according to claim 1, wherein the display area and the thermal head are arranged and formed on the rear transparent substrate.   The display device according to claim 1, wherein the thermal head is disposed and formed in the vicinity of the line sensor, and the printing sheet travels on the thermal head by the traveling unit.

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