JPH0894992A - Liquid crystal display element - Google Patents

Abstract

PURPOSE: To utilize the electric power obtd. in solar batteries for a part of power source power and to save the electric power of an electronic apparatus by providing the inside substrate of one of substrates facing each other across liquid crystals with a solar batteries in correspondence to the spacings between respective pixels. CONSTITUTION: The inside surface of the front surface side substrate 2 is provided with the solar batteries 15 for obtaining the electric power by utilizing the incident light on liquid crystal display elements in correspondence to the spacings between color filters 14R, 14G, 14B of respective colors. The parts corresponding to the respective pixels are formed as grid-shaped patterns over the entire part of the display regions of the liquid crystal display elements. The solar batteries 15 consist of upper electrodes 16 formed on the substrate 2 surface, p type and n type semiconductor films 17p, 17n laminated on the upper electrodes 16 and lower electrodes 18 formed thereunder. The electric power generated by the solar batteries 15 are taken out of the terminal parts of the upper and lower electrodes 16, 17. Then, the large electric power is obtd. by efficiently and effectively utilizing the light not used for display without generating the degradation in the brightness of the display and the opening rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device provided with a solar cell.

[0002]

2. Description of the Related Art Liquid crystal display elements are classified into active matrix type and simple matrix type.
Further, the active matrix type liquid crystal display element includes one using a TFT (thin film transistor) as an active element and one using a two-terminal non-linear resistance element such as MIM as an active element. These dot matrix type liquid crystal display elements Are widely used as display bodies for various electronic devices such as personal computers and television receivers.

[0003]

However, an electronic device using the above liquid crystal display element requires a high-intensity backlight to obtain a bright display, although the power required to drive the display of the liquid crystal display element is small. Therefore, there was a problem that power saving was difficult.

That is, as the above-mentioned liquid crystal display element, generally, a transmissive type in which light from a backlight is made incident from the back side to display is used. Electronic equipment using this transmissive liquid crystal display element. Consumes a large amount of power to turn on the backlight.

This is remarkable when the liquid crystal display element is a color display element in which color filters of a plurality of colors (for example, red, green and blue) are provided corresponding to each pixel, and this color display is performed. In an electronic device using an element, in order to compensate for a decrease in display brightness due to absorption of light in the color filter, the brightness of the backlight needs to be increased, so that the power consumption of the backlight becomes larger. I will end up.

Some electronic devices are equipped with elements that consume a large amount of electric power, such as a speaker in a television receiver. In this type of electronic device, not only a backlight but also a speaker and the like are used. This element consumes a large amount of power.

On the other hand, in addition to the transmissive type which uses a backlight, the liquid crystal display element utilizes external light such as natural light and indoor illumination light, and external light incident from the front side is reflected by the reflection plate on the rear surface side. A reflective type that reflects and displays, or a half mirror is used for the reflective plate, performs reflective display in a bright place where sufficient external light is obtained, and allows light from the backlight to enter from the back side in a dark place. There is also a reflective / transmissive type that displays as.

Since a reflective liquid crystal display element utilizing external light does not require a backlight, an electronic device using this reflective liquid crystal display element does not consume power in the backlight, but a speaker. Those having such an element have a problem that the power consumption in this element is large.

Further, since the electronic equipment using the liquid crystal display element of the reflective / transmissive type is used by turning on the backlight only when sufficient external light cannot be obtained, the transmissive liquid crystal is used. The backlight consumes less power than the one using a display element, but the backlight still consumes a large amount of power, and those equipped with elements such as speakers consume a large amount of power even with this element. Resulting in.

The consumption of electric power by the elements such as the backlight and the speaker has been a problem particularly in electronic equipment using a battery as a power source, such as portable electronic equipment. The larger the value, the shorter the battery life. The present invention provides a liquid crystal display device,
An object of the present invention is to provide a device having a function of obtaining electric power by using incident light and to save power of electronic devices.

[0011]

A liquid crystal display device according to the present invention has an inner surface of at least one of a front surface side substrate and a rear surface side substrate which face each other with a liquid crystal sandwiched therebetween so as to correspond to a gap between pixels. It is characterized in that a solar cell is provided.

In the present invention, the display electrode on the side of the substrate provided with the solar cell may be formed on the insulating film provided so as to cover the solar cell. When the solar cell is provided on the inner surface of the front surface side substrate, the solar cell may also serve as a black mask corresponding to the gap between the pixels.

In order to make the solar cell also serve as a black mask, for example, the solar cell is formed on the substrate surface by the first
Electrode, a p-type and n-type semiconductor film stacked on the first electrode, and a second electrode formed on the semiconductor film, and the first and second electrodes are formed. Of the electrodes, the electrode facing the light incident surface side of the liquid crystal display element may be formed of a transparent conductive film, and the other electrode may be formed of a light shielding metal film.

In order to make the solar cell also serve as a black mask, the solar cell may be formed of a thick semiconductor laminated film in which p-type and n-type semiconductor films are laminated. Further, in the color liquid crystal display element, it is desirable that a color filter of a plurality of colors is provided on the inner surface of the front surface side substrate so as to correspond to each pixel, and the solar cell is provided between these color filters.

Further, when the solar cell is provided on the inner surface of the back side substrate, in the liquid crystal display element in which the black mask is provided on the inner surface of the front side substrate so as to correspond to the gap between the pixels, the light incident on the solar cell is incident. The surface may be opposed to the back surface side of the liquid crystal display element.

In the reflective / transmissive type liquid crystal display element, the solar cells may be provided on the inner surfaces of both substrates. In that case, the light incident surface of the solar cells provided on the front substrate is The light incident surface of the solar cell provided on the rear surface side substrate may be opposed to the front surface side of the liquid crystal display element, and may be opposed to the rear surface side of the liquid crystal display element.

[0017]

In the liquid crystal display element of the present invention, the solar cell is provided on the inner surface of at least one of the substrates so as to correspond to the gap between the pixels. Electric power is generated by receiving light incident on the gap between the pixels.

That is, this liquid crystal display element has a function of obtaining electric power by utilizing incident light to the liquid crystal display element. If this liquid crystal display element is used as a display body of electronic equipment, the solar cell Since the electric power obtained in step 1 can be used as a part of the electric power of the power source, it is possible to save electric power of the electronic device.

Moreover, in this liquid crystal display element, since the solar cells are provided in correspondence with the gaps between the respective pixels, incident light to the pixel portion is not absorbed by the solar cells, and therefore, The brightness of the display and the aperture ratio are not lowered, and the light not used for the display (the light incident on other than the pixel portion) is effectively used without waste,
You can get big power.

In the liquid crystal display device of the present invention, if the display electrode on the side of the substrate on which the solar cell is provided is formed on the insulating film provided to cover the solar cell, the display electrodes on the pair of substrates are formed. An electric field corresponding to the voltage applied between can be applied to the liquid crystal without being affected by the solar cell.

Further, when the solar cell is provided on the inner surface of the front side substrate of the liquid crystal display element, if the solar cell also serves as a black mask corresponding to the gap between the pixels, the displayed image can be clearly seen. Since it is not necessary to separately provide the black mask, the manufacturing of the liquid crystal display device can be facilitated.

In this case, the solar cell is formed by forming a first electrode formed on a substrate surface, p-type and n-type semiconductor films laminated on the first electrode, and the semiconductor film on the first electrode. Of the first and second electrodes, the electrode facing the light incident surface side of the liquid crystal display element is formed of a transparent conductive film, and the other electrode is formed of a light-shielding metal. If it is formed of a film, transmitted light is blocked by the electrode made of the metal film, so that this solar cell can also serve as a black mask.

The solar cell may be composed of a thick semiconductor laminated film in which p-type and n-type semiconductor films are laminated. Since it is almost absorbed in the laminated film, this solar cell can also serve as a black mask.

Furthermore, when the present invention is applied to a color liquid crystal display device, a color filter of a plurality of colors is provided on the inner surface of the front surface side substrate so as to correspond to each pixel, and the solar cell is provided between these color filters. By providing, it is possible to prevent the liquid crystal display element from becoming thicker due to the provision of the solar cell.

When the solar cell is provided on the inner surface of the back side substrate of the liquid crystal display element, the liquid crystal display element is provided with a black mask corresponding to the gap between pixels on the inner surface of the front side substrate. Also, even in that case, if the light incident surface of the solar cell is opposed to the back surface side of the liquid crystal display element, the light is incident on the liquid crystal display element from the back surface side of the liquid crystal display element, so that power is supplied to the solar cell. Can be generated.

When the liquid crystal display element is of a reflective / transmissive type, the solar cell may be provided on the inner surface of either one of the front and back substrates, but this solar cell is provided on the inner surface of both substrates. Provided respectively, the light incident surface of the solar cell provided on the surface side substrate is opposed to the surface side of the liquid crystal display element,
If the light incident surface of the solar cell provided on the back side substrate is made to face the back side of the liquid crystal display element, electric power will be obtained by the solar cell provided on the front side substrate during reflective display using external light. In the case of a transmissive display that uses light from a backlight, electric power can be obtained by a solar cell provided on the back side substrate.

[0027]

1 to 6 show a first embodiment of the present invention. FIG. 1 is a plan view of a part of a liquid crystal display device, and FIGS. 2 and 3 are lines II-II and III in FIG. It is an expanded sectional view which follows the III line.

In the active matrix type liquid crystal display element of this embodiment, a TFT (thin film transistor) is used as an active element.
Of the pair of front and back substrates (transparent substrate made of glass plate or the like) 1 and 2 that face each other across the liquid crystal LC, the back-side substrate (lower substrate in FIGS. 2 and 3)
On the inner surface of 1, transparent pixel electrodes 3 are arranged and formed in a row direction (horizontal direction in FIG. 1) and a column direction (vertical direction in FIG. 1), and TFTs 4 are arranged corresponding to these pixel electrodes 3, respectively. It is set up.

As shown in FIGS. 1 and 2, the TFT 4 includes a gate electrode 5 formed on the rear substrate 1 and
A gate insulating film 6 covering the gate electrode 5, an i-type semiconductor film 7 made of a-Si (amorphous silicon) formed on the gate insulating film 6 so as to face the gate electrode 5, and the i-type semiconductor film 7. A source electrode 9s and a drain electrode 9d are formed on the semiconductor film 7 via an n-type semiconductor film 8 made of a-Si doped with an n-type impurity.

Further, on the back-side substrate 1, one side of each pixel electrode row is provided, and the TFTs of each row are arranged.
4, a gate line 10 for supplying a gate signal is wired, and the gate electrode 5 of the TFT 4 in each row is integrally formed with the gate line 10 corresponding to that row. The gate insulating film 6 of the TFT 4 is formed over almost the entire surface of the substrate 1, and the gate line 10 is covered with the gate insulating film 6 except for its terminal portion.

Further, on the gate insulating film 6, along each side of each pixel electrode column, each T of each column is formed.
A data line 11 for supplying a data signal having a potential corresponding to image data is wired to the FT4, and the TFTs 4 in each column are connected.
Each of the drain electrodes 9d is connected to the data line 11 corresponding to the column.

In this embodiment, the data line 11 is integrated with the drain electrode 9d of the TFT 4, but the data line 11 is connected to the gate insulating film 6 described above.
An interlayer insulating film may be provided in the upper data line wiring region and wiring may be performed thereon. In that case, a contact hole corresponding to the drain electrode 9d of each TFT 4 is formed in the interlayer insulating film, and this contact is formed. The data line 11 may be connected to the drain electrode 9d of the TFT 4 in the hole.

The gate insulating film 6 is a transparent insulating film made of Si N (silicon nitride) or the like, and the pixel electrode 3 is formed on the gate insulating film 6 and has one side edge thereof. Is connected to the source electrode 9s of the corresponding TFT 4 at the end.

On the other hand, on the inner surface of the front side substrate (upper side substrate in FIGS. 2 and 3) 2, a plurality of colors for coloring transmitted light to obtain a color display, for example, three colors of red, green and blue are provided. A color filter 14R, 14G, 14B and a solar cell 15 for obtaining electric power by using incident light to the liquid crystal display element are provided, and a transparent insulating film 13 covering them is provided on the solar cell 15. All the pixel electrodes 3 on the back substrate 1 side
Is provided with a transparent counter electrode 12 in the form of a film.

The color filters 14R, 14G, 14
B is each pixel of the liquid crystal display element (the portion where the pixel electrode 3 and the counter electrode 12 face each other with the liquid crystal LC in between).
The color filters 14R, 14G and 14B are alternately arranged in the row direction and the column direction in the order of the red filter 14R, the green filter 14G and the blue filter 14B. There is.

The solar cell 15 is provided between the color filters 14R, 14G and 14B of the respective colors so as to correspond to the gap between the pixels.
Are formed in a lattice pattern in which portions corresponding to the respective pixels are opened over the entire display area of the liquid crystal display element. The portion of the solar cell 15 corresponding to the TFT 4 is formed to have a width that covers the TFT 4.

FIG. 4 is an enlarged cross-sectional view of a part of the front surface side substrate 2, wherein the solar cell 15 has a first electrode (hereinafter referred to as an upper electrode) 16 formed on the surface of the substrate 2 and P-type and n-type semiconductor film 1 laminated on the upper electrode 16
7p and 17n, and a second electrode (hereinafter referred to as a lower electrode) 18 formed on the semiconductor films 17p and 17n.

The solar cell 15 receives electric light from the outside to generate electric power, like the commercially available solar cell,
The power generated by the solar cell 15 (photovoltaic power generated on both sides of the pn junction formed by the p-type and n-type semiconductor films 17p and 17n) is applied to the terminal portions of the upper and lower electrodes 16 and 17 (not shown). , Formed on the side edge of the front side substrate).

The upper and lower electrodes 1 of this solar cell 15
Among the electrodes 6 and 18, the electrode facing the light incident surface side of the liquid crystal display element is formed of a transparent conductive film made of ITO or the like, and the other electrode makes the displayed image clearly on the solar cell 15. In order to double as a black mask for
It is formed of a light-shielding metal film such as Cr (chrome).

Thus, the upper and lower electrodes 1 of the solar cell 15
If the electrode on the side opposite to the light incident surface side of 6, 6 is formed of a light-shielding metal film, the transmitted light is shielded by the electrode made of the metal film, so that the solar cell 15 also serves as a black mask. Can be made.

The liquid crystal display element of this embodiment is of a transmissive type in which light from a back light (not shown) is incident from the back surface side for display. Therefore, in this embodiment, the lower portion of the solar cell 15 is used. The electrode 18 is formed of a transparent conductive film, and the upper electrode 16 is formed of a light shielding metal film.

FIG. 5 shows a method for forming the solar cell 15 described above. In the solar cell 15, each film constituting the solar cell 15 is formed on the front surface side substrate 2, and these solar cell constituent films are formed. It is formed by a patterning method using a photolithography method.

The method for forming the solar cell 15 will be described. First, as shown in FIG. 5A, a solar cell constituent film, that is, a light-shielding metal film such as Cr is formed on the front side substrate 2. Upper electrode 16 and p-type impurity-doped a-
P-type semiconductor film 17p made of Si, n-type semiconductor film 17n made of a-Si doped with n-type impurities, and ITO
And the lower electrode 18 made of a transparent conductive film such as The upper electrode 16 and the lower electrode 18 are formed by a sputtering apparatus, and the p-type semiconductor film 17p and the n-type semiconductor film 17n are continuously formed by a plasma CVD apparatus.

Next, a photoresist is coated on the above solar cell constituent film (on the lower electrode 18) and its exposure,
By a development process, a resist mask 30 having a grid pattern corresponding to the gaps between the pixels is formed, and in this state, the solar cell constituent film is etched as shown in FIG. A solar cell 15 having a pattern is formed. The resist mask 30 is peeled off after the solar cell 15 is formed.

Further, the color filters 14R, 14
G and 14B are formed after the solar cell 15 is formed, and the color filters 14R, 14G, and
14B is formed as follows.

FIG. 6 shows the color filters 14R, 14 described above.
The method of forming G and 14B is shown, and in this figure, the solar cell 15 is shown in black. FIG. 6A
6B and 6B are process diagrams of forming a first color filter, for example, a red filter 14R. The red filter 14R is the front side substrate 2 on which the solar cell 15 is formed.
Then, a red photosensitive color resist (a photosensitive resist containing a red pigment) is applied onto the above by a transfer printing method or the like to form a red resist film 14R 'as shown in FIG. 6 (a). The resist film 14R 'is exposed from the opposite surface (lower surface) side of the substrate 2 using an exposure mask 31 having an opening corresponding to the formation region of the red filter 14R, and then the exposed resist film 14R' is developed. Process,
As shown in FIG. 6B, the remaining resist film is formed by a method of forming the red filter 14R.

Further, FIGS. 6C and 6D show the second
FIG. 9 is a process diagram of forming a color filter of a color of, for example, a green filter 14G. The green filter 14G is formed by forming the red filter 14R, and then forming a green photosensitive color resist (photosensitive material to which a green pigment is added) on the substrate 2. (A positive resist) is applied by a transfer printing method or the like to form a green resist film 14G 'as shown in FIG. 6 (c).
4G ′ is exposed from the opposite surface side of the substrate 2 using the exposure mask 32 having an opening corresponding to the formation region of the green filter 14G, and then the exposed resist film 14 is exposed.
G'is developed, and the remaining resist film is formed as a green filter 14G as shown in FIG. 6D.

Further, FIGS. 6E and 6F are process diagrams of forming a third color filter, for example, a blue filter 14B. The blue filter 14B includes the red filter 14R and the green filter 14G. Then, a blue photosensitive color resist (photosensitive resist containing a blue pigment) is applied on the substrate 2 by a transfer printing method or the like to form a blue resist film 14B 'as shown in FIG. 6 (e).
And the resist film 14B 'is formed on the blue filter 1
Exposure mask 3 having an opening corresponding to the formation region of 4B
3 is used to perform exposure processing from the opposite surface side of the substrate 2, and thereafter,
The exposed resist film 14B 'is subjected to a development process, and then, FIG.
The remaining resist film is formed as a blue filter 14B as shown in (f) of FIG.

That is, the method for forming the solar cell 15 and the color filters 14R, 14G and 14B is as follows.
A solar cell 15 is formed on the substrate 2 by forming a solar cell constituent film and patterning the film. After that, a negative photosensitive color resist is applied on the substrate 2 and exposed from the opposite surface side of the substrate 2. The color filters 14R, 14G, and 14B for the respective colors are sequentially formed by a method of performing development processing later.

In this method of forming a solar cell and a color filter, after forming the solar cell 15 also serving as a black mask on the substrate 2, the color filters 14R, 14G,
14B and the color filter 14
Color resist film 1 when forming R, 14G and 14B
Since the exposure processing of 4R ', 14G', and 14B 'is performed by irradiating light from the opposite surface side of the substrate 2, the exposure areas of the color resist films 14R', 14G ', and 14B' are exposed. However, it is also regulated by the solar cell 15 which also serves as a black mask.

Therefore, according to the method for forming the solar cell and the color filter, the color resist films 14R 'and 14R' are formed.
During the exposure processing of G'and 14B ', the exposure mask 31,
Even if there is some error in the alignment accuracy of 32, 33, the portions of the color resist films 14R ', 14G', 14B 'on the solar cell 15 are not exposed, and therefore the formed color filter 14R is formed. , 14G, 14
The edge of B does not overlap the solar cell 15 and a large step is not formed in this portion.

According to the method of forming the solar cell and the color filter, the color resist films 14R ', 14R are formed.
Since the exposure areas of G'and 14B 'can be regulated by the solar cell 15 which also serves as a black mask, the shape and dimensional accuracy of the openings of the exposure masks 31, 32 and 33 may be rough to some extent. , 3
3 is also easy to manufacture.

Then, the solar cell 15 and the color filters 14R, 14G and 14B are formed and the counter electrode 12 is provided on the transparent insulating film 13 formed so as to cover them, the pixel electrode 3 and The back side substrate 1 on which the TFTs 4 and the like are arranged is bonded via a frame-shaped sealing material (not shown) with the electrode formation surfaces facing each other. Is filled in the area surrounded by the sealing material.

The liquid crystal display element of this embodiment is of a twisted nematic type, and is composed of both substrates 1 and 2.
The molecules of the liquid crystal LC filled in between are restricted in the orientation direction on the substrates 1 and 2 side by the orientation films 19 and 20 provided on the electrode formation surfaces of the substrates 1 and 2, respectively.
The two are twist-oriented at a predetermined twist angle. Further, in FIGS. 2 and 3, reference numerals 21 and 22 denote a pair of polarizing plates arranged on the front surface side and the back surface side of the liquid crystal display element.

The liquid crystal display device of the above embodiment is a transmissive liquid crystal display device in which light from a backlight (not shown) is incident from the back surface side for display, and the transmissive liquid crystal display device requires a backlight. An electronic device using this liquid crystal display element consumes a large amount of power for lighting the backlight.

Incidentally, in an electronic apparatus having an element which consumes a large amount of power such as a speaker in a television receiver, not only the backlight but also an element such as a speaker consumes a large amount of power.

However, in the above liquid crystal display element, the solar cell 15 is provided on the inner surface of the front surface side substrate 2 so as to correspond to the gap between the pixels, and therefore the solar cell 15 is
Electric power is generated by receiving the incident light of the light (light from the backlight) incident on the liquid crystal display element to the gap between the pixels.

In this case, in the liquid crystal display device, of the light that has entered the gaps between the pixels, the light that has entered the TFT4 portion provided on the backside substrate 1 is blocked by the TFT4, but the other light. The light that has entered the portion passes through the liquid crystal LC and enters the solar cell 15 on the front surface side substrate 2 side.

That is, the liquid crystal display element has a function of obtaining electric power by using incident light to the liquid crystal display element, and the liquid crystal display element is used for various electronic devices such as a personal computer and a television receiver. When used as a display body of a device, the electric power obtained by the solar cell 15 can be used as a part of the power supply, so that the consumption of the electric power supplied from the outside to the electronic device can be reduced, and as a result, the electronic device can be used. Power saving can be achieved.

The electric power generated by the solar cell 15 is taken out from the terminals (not shown) of the upper and lower electrodes 16 and 17 of the solar cell 15, and is passed through a voltage stabilizing circuit to an element such as a backlight or a speaker. It suffices to supply it to a power supply unit or the like.

Moreover, in the above liquid crystal display element, since the solar cell 15 is provided so as to correspond to the gap between each pixel, incident light to the pixel portion is not absorbed by the solar cell, and The display brightness and the aperture ratio are not lowered, and light not used for display (incident light to the portion other than the pixel portion) is effectively used without waste, and a large amount of power can be obtained.

Further, the liquid crystal display element is a solar cell 15
Since the display electrode (opposite electrode in this embodiment) 12 on the front surface side substrate 2 side provided with is formed on the transparent insulating film 13 provided so as to cover the solar cell 15, the solar cell 1
5 is insulated from the display electrode 12 by the insulating film 13, and the voltage applied between the display electrodes of the pair of substrates 1 and 2 (between the pixel electrode 3 and the counter electrode 12) is adjusted. The electric field can be applied to the liquid crystal LC without being affected by the solar cell 15.

Furthermore, in the above embodiment, the solar cell 1
5 is provided on the inner surface of the front substrate 2 of the liquid crystal display element, and
Since the solar cell 15 also serves as a black mask corresponding to the gap between the pixels, it is not necessary to separately provide a black mask for making the displayed image look clear.
Therefore, the manufacture of the liquid crystal display element can be facilitated.

In this case, in the above-described embodiment, the solar cell 15 includes the upper electrode 16 formed on the surface of the substrate 2 and the p-type and n-type semiconductor films 1 laminated on the upper electrode 16.
7p and 17n and a lower electrode 18 formed on the semiconductor films 17p and 17n, and the upper and lower electrodes 16 and 18 are opposed to the light incident surface side (rear surface side) of the liquid crystal display element. Since the lower electrode 18 is formed of a transparent conductive film and the upper electrode 16 is formed of a light-shielding metal film,
The transmitted light can be blocked by the upper electrode 16 made of the metal film, and thus the solar cell 15 can also serve as a black mask.

Further, the liquid crystal display element is a color liquid crystal display element provided with color filters of a plurality of colors. In the above embodiment, however, color filters are provided on the inner surface of the front substrate 2 so as to correspond to respective pixels. 14R, 14G, 14B are provided, and the solar cell 15 is provided between these color filters 14R, 14G, 14B.
It is possible to prevent the liquid crystal display element from becoming thick due to the provision of. Here, the color filters 14R, 14G, 14
B may be formed in a mosaic shape or a stripe shape, and the same effect can be obtained in any case.

In the first embodiment, the solar cell 1
5 is composed of a semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated, and upper and lower electrodes 16 and 18 sandwiching this semiconductor laminated film.
May be composed only of a semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated.

FIG. 7 is a sectional view of a part of a liquid crystal display device showing a second embodiment of the present invention. In the liquid crystal display device of this embodiment, a solar cell 15 is provided with p-type and n-type semiconductor films 17.
It is configured by only a semiconductor laminated film in which p and 17n are laminated, and the thickness of the semiconductor laminated film is increased.

In the liquid crystal display element of this embodiment, the solar cell 15 is composed only of the semiconductor laminated film, but the other structure is the same as that of the first embodiment described above, and therefore the duplicated description will be omitted. The same symbols are attached to the drawings and omitted.

Although not shown, in this embodiment,
A conductive film for taking out the electric power generated by the solar cell 15 is formed at the peripheral edge or one side edge of the p-type semiconductor film 17p and the n-type semiconductor film 17n that form the solar cell 15.

In this embodiment, the solar cell 15 is composed only of the semiconductor laminated film in which the p-type and n-type semiconductor films 17p and 17n are laminated. However, the thickness of this semiconductor laminated film is increased. , The transmitted light can be almost absorbed in the semiconductor laminated film, and therefore the solar cell 15
While being composed of only the semiconductor laminated film,
The solar cell 15 can also serve as a black mask.

The liquid crystal display element of this embodiment is of a transmissive type which allows light from a backlight (not shown) to enter from the back surface side for display, and the solar cell 15 enters from the back surface side of the liquid crystal display element. In this embodiment, of the p-type and n-type semiconductor films 17p and 17n forming the solar cell 15, the semiconductor film on the side where the light enters (p-type semiconductor film in the figure) is received. 17p) as a thin film so that both the p-type semiconductor film 17p and the n-type semiconductor film 17n can receive a sufficient amount of light, and the semiconductor film on the side opposite to the light incident side (the n-type semiconductor film 17n in the figure). )
The solar cell 15 also functions as a black mask by increasing the thickness of the film.

In the liquid crystal display element of this embodiment, the solar cell 15 composed only of the semiconductor laminated film is provided on the inner surface of the front substrate 2, and the solar cell 15 also serves as a black mask. Even if the light of (6) enters the liquid crystal display element from the surface side thereof, the light of the light incident on the black mask portion can be absorbed by the solar cell 15, and therefore Cr or the like can be formed on the inner surface of the front surface side substrate. Unlike the case where the black mask made of the metal film is provided, external light is reflected by the black mask surface, and the display does not appear to be glare.

Also in the liquid crystal display element of this embodiment, the color filter 1 provided on the inner surface of the front surface side substrate 2 thereof is also used.
4R, 14G, and 14B form the solar cell 15 on the inner surface of the front-side substrate 2 (p-type and n-type semiconductor films 17).
p, 17n film formation and patterning)
After that, it may be formed by the method shown in FIG. 6, and in that case also, in the exposure process of the color resist film when forming the color filters 14R, 14G, and 14B, the exposed area of the solar cell 15 also serves as a black mask. Since it is also regulated by the
The edges of 4G and 14B do not overlap the solar cell 15 and a large step is not formed in this portion.

In the liquid crystal display elements of the first and second embodiments, the solar cell 15 is formed on the inner surface of the front surface side substrate 2.
However, the solar cell 15 may be provided on the inner surface of the rear substrate 1.

FIG. 8 is a sectional view of a part of a liquid crystal display device showing a third embodiment of the present invention. The liquid crystal display device of this embodiment has a gap between pixels on the inner surface of the back side substrate 1. The solar cell 15 is provided corresponding to the above.

In the liquid crystal display element of this embodiment, the solar cell 15 is provided on the inner surface of the back side substrate 1,
Since other configurations are the same as those of the above-described first embodiment, the duplicated description will be omitted by giving the same reference numerals to the drawings.

However, in this embodiment, the solar cell 15 provided on the inner surface of the rear substrate 1 is covered with the transparent insulating film 23, and the pixel electrode 3 and the TFT 4 are provided thereon, and the solar cell 15, the TFT 4 and the TFT 4 are provided. The insulating film 23 insulates the gate line and the like from the insulating film 23, and the solar cell 15 affects the electric field according to the voltage applied between the pixel electrode 3 and the counter electrode 12 of the front substrate 2. Without liquid crystal L
It can be applied to C.

Further, in this embodiment, the color filters 14R, 14G and 14B corresponding to the respective pixels are provided on the inner surface of the front surface side substrate 2 of the liquid crystal display element, and between the color filters 14R, 14G and 14B. A black mask 24 is provided in correspondence with the gaps between the pixels.

Like the color filters 14R, 14G and 14B, the black mask 24 is formed by a method of applying a photosensitive color resist on the substrate 2 and exposing and developing it. In the example,
The insulating film 13 provided in the first embodiment is omitted, and the counter electrode 12 is formed directly on the color filters 14R, 14G, 14B and the black mask 24.

The liquid crystal display element of this embodiment is of a transmissive type in which light from a backlight (not shown) is incident from the back surface side for display, and the light incident surface of the solar cell 15 is the liquid crystal display element. It faces the back side.

In this embodiment, since the black mask 24 is provided on the inner surface of the front surface side substrate 2, it is not necessary for the solar cell 15 to also serve as the black mask. Therefore, the upper and lower electrodes 16 of the solar cell 15 are not provided. , 18 may be formed of a transparent conductive film made of ITO or the like, or the electrode 1 on the light incident side facing the back surface side of the liquid crystal display element.
6 may be formed of a transparent conductive film, and the other electrode 18 may be formed of a metal film.

Also in the liquid crystal display element of this embodiment, since the solar cell 15 is provided on the inner surface of the back side substrate 1 so as to correspond to the gap between the pixels, the solar cell 15 is used for the liquid crystal display. Electric power is generated by receiving the incident light of the light (light from the backlight) that is incident on the gap between the pixels, so that if this liquid crystal display device is used as a display body of various electronic devices, By using the electric power obtained by the solar cell 15 as a part of the electric power of the power source, it is possible to save the electric power of the electronic device.

In this embodiment, the black mask 24 is made of a color resist, but the black mask 24 may be made of a metal film such as Cr. Further, in the liquid crystal display element of this embodiment, especially when the black mask 24 is formed of a color resist, the color filters 14R, 14G, which are provided on the inner surface of the front side substrate 2,
14B on the inner surface of the front-side substrate 2 with a black mask 2
After forming No. 4, it is desirable to form by the method shown in FIG.

After the black mask 24 is thus formed, the color filters 14R and 14R are formed by the method shown in FIG.
When G and 14B are formed, the exposure area of the color resist film is also regulated by the black mask 24 during the exposure processing of the color resist film.
The edges of 14G and 14B do not overlap the black mask 24 and a large step is not formed in this portion.

Further, in this embodiment, the solar cell 15 is
A semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated, and upper and lower electrodes 1 sandwiching the semiconductor laminated film
6 and 18, the solar cell 15 may be composed of only a semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated, as in the second embodiment described above. Good.

The liquid crystal display elements of the first to third embodiments are all color filters 14R, 14G and 1.
4B is a color liquid crystal display device, the present invention is
The present invention can also be applied to a monochrome display type dot matrix type liquid crystal display device having no color filter.

Further, all of the liquid crystal display elements of the above-mentioned first to third embodiments are of the transmissive type in which the light from the backlight is incident from the back surface side for display, but the present invention is transparent. Not only the liquid crystal type, but also the reflective dot matrix liquid crystal display element that uses external light such as natural light or indoor illumination light and reflects the external light incident from the front side by the reflection plate on the back side. Applicable to the above first
In any of the third to third embodiments, the solar cell 15 is turned upside down (the light incident surface is opposed to the front surface side of the liquid crystal display element) to obtain a reflective display element. Can be used.

In this case, if the liquid crystal display element of the third embodiment is of a reflection type, the light incident on the TFT4 portion of the light incident on the gap between the pixels is blocked by the TFT4. Light incident on the other portion passes through the liquid crystal LC and enters the solar cell 15 on the front surface side substrate 2 side.
Even if the liquid crystal display device of the third embodiment is of a reflective type, it is possible to obtain electric power from the solar cell 15.

Further, according to the present invention, a half mirror is arranged on the back surface side of the liquid crystal display element to perform reflection type display in a bright place where sufficient external light can be obtained, and in a dark place, the light from the backlight is placed on the back surface side. The present invention can also be applied to a reflective / transmissive dot matrix liquid crystal display device that is incident on and displayed from a solar cell 15 by allowing external light to enter the solar cell 15 when used as a reflective device. Electric power may be obtained, or, when used as a transmissive element, light from a backlight may be incident on the solar cell 15 to obtain electric power.

Further, when the present invention is applied to the reflection / transmission type dot matrix type liquid crystal display device,
The solar cell 15 may be provided on the inner surface of either one of the front and back substrates, but the solar cell 15 is provided on the inner surfaces of both the substrates 1 and 2 and the solar cell 15 provided on the front substrate 2 If the light incident surface is opposed to the front surface side of the liquid crystal display element and the light incident surface of the solar cell 15 provided on the rear substrate 1 is opposed to the rear surface side of the liquid crystal display element, a reflection type display utilizing external light is provided. In this case, the solar cell 1 provided on the front substrate 2
In the case of a transmissive display in which electric power is obtained by 5 and light from a backlight is used, the solar cell 15 provided on the rear substrate 1 is used.
You can get power by.

That is, FIG. 9 is a sectional view of a part of a liquid crystal display element showing a fourth embodiment of the present invention. This liquid crystal display element has a half mirror 25 arranged on the back side thereof and is used for both reflection and transmission. The solar cell 15 is provided on the inner surfaces of both substrates 1 and 2, and the solar cell 15 provided on the front substrate 2 also serves as a black mask.

Although the liquid crystal display element of this embodiment is of a monochrome display type having no color filter,
Except that a color filter is not provided, the structure on the front surface side substrate 2 side is the same as that of the first embodiment described above, and the structure on the back surface side substrate 1 side is the same as that of the third embodiment described above. Therefore, the detailed description thereof will be omitted by adding the same reference numerals to the drawings.

However, in this embodiment, the solar cell 15
Is composed of a semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated, and upper and lower electrodes 16 and 18 sandwiching this semiconductor laminated film.
Similar to the second embodiment described above, it may be configured only by a semiconductor laminated film in which p-type and n-type semiconductor films 17p and 17n are laminated.

Furthermore, in the above-mentioned first to fourth embodiments, the semiconductor laminated film of the solar cell 15 is constructed such that the p-type semiconductor film 17p is opposed to the light incident side. The n-type semiconductor film 17n may be opposed to the light incident side, or the i-semiconductor thin film may be interposed between the p-type semiconductor film 17p and the n-type semiconductor film 17n.

Further, the liquid crystal display element of each of the above-mentioned embodiments is
The present invention is an active matrix type using FT4 as an active element, but the present invention is applicable to an active matrix type liquid crystal display element using a two-terminal non-linear resistance element such as MIM as an active element, a simple matrix type or a segment display type. It can also be applied to the liquid crystal display element.

[0096]

Since the liquid crystal display element of the present invention is provided with a solar cell on the inner surface of at least one of the substrates so as to correspond to the gap between the pixels, the incident light to the liquid crystal display element is utilized. Therefore, if this liquid crystal display element is used as a display body of an electronic device, the electric power obtained by the solar cell can be used as a part of the power source power, so that the power saving of the electronic device can be achieved. You can measure.

Moreover, in this liquid crystal display element, since the solar cell is provided so as to correspond to the gap between the pixels, incident light to the pixel portion is not absorbed by the solar cell, and therefore, The brightness of the display and the aperture ratio are not lowered, and the light not used for the display (the light incident on other than the pixel portion) is effectively used without waste,
You can get big power.

Further, in the liquid crystal display device of the present invention, if the display electrode on the side of the substrate on which the solar cell is provided is formed on the insulating film provided to cover the solar cell, the display electrodes on the pair of substrates are formed. An electric field corresponding to the voltage applied between can be applied to the liquid crystal without being affected by the solar cell.

Further, when the solar cell is provided on the inner surface of the front side substrate of the liquid crystal display element, if the solar cell also serves as a black mask corresponding to the gap between the pixels, the displayed image can be clearly seen. Since it is not necessary to separately provide the black mask, the manufacturing of the liquid crystal display device can be facilitated.

In this case, the solar cell is formed by forming the first electrode formed on the substrate surface, the p-type and n-type semiconductor films laminated on the first electrode, and the semiconductor film on the first electrode. Of the first and second electrodes, the electrode facing the light incident surface side of the liquid crystal display element is formed of a transparent conductive film, and the other electrode is formed of a metal film. If formed, the transmitted light is blocked by the electrode made of the metal film, so that this solar cell can also serve as a black mask.

Further, the solar cell may be composed of a thick semiconductor laminated film in which p-type and n-type semiconductor films are laminated. Since it is almost absorbed in the laminated film, this solar cell can also serve as a black mask.

Further, when the present invention is applied to a color liquid crystal display element, a color filter of a plurality of colors is provided on the inner surface of the front surface side substrate so as to correspond to each pixel, and the solar cell is provided between these color filters. By providing, it is possible to prevent the liquid crystal display element from becoming thicker due to the provision of the solar cell.

When the solar cell is provided on the inner surface of the back side substrate of the liquid crystal display element, the liquid crystal display element is provided with a black mask corresponding to the gap between pixels on the inner surface of the front side substrate. Also, even in that case, if the light incident surface of the solar cell is opposed to the back surface side of the liquid crystal display element, the light is incident on the liquid crystal display element from the back surface side of the liquid crystal display element, so that power is supplied to the solar cell. Can be generated.

When the liquid crystal display element is of a reflective / transmissive type, the solar cell may be provided on the inner surface of one of the front and back substrates, but this solar cell is provided on the inner surface of both substrates. Provided respectively, the light incident surface of the solar cell provided on the surface side substrate is opposed to the surface side of the liquid crystal display element,
If the light incident surface of the solar cell provided on the back side substrate is made to face the back side of the liquid crystal display element, electric power will be obtained by the solar cell provided on the front side substrate during reflective display using external light. In the case of a transmissive display that uses light from a backlight, electric power can be obtained by a solar cell provided on the back side substrate.

[Brief description of drawings]

FIG. 1 is a plan view of a part of a liquid crystal display element showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged cross-sectional view of a part of a front surface side substrate in the liquid crystal display element of the first embodiment.

FIG. 5 is a diagram showing a method for forming a solar cell 15,
(A) is a sectional view of a state in which a solar cell constituent film is formed on a substrate, and (b) is a sectional view of a state in which the solar cell constituent film is patterned.

FIG. 6 is a diagram showing a method of forming a color filter,
(A) and (b) are cross-sectional views of a color resist film for forming a color filter of a first color after exposure and development, and (c) and (d) of a second color. Sectional drawing of the state of the exposure processing of the color resist film for forming a color filter, and the state after a development processing, (e)
And (f) are cross-sectional views of a color resist film for forming a color filter of a third color in an exposed state and a developed state.

FIG. 7 is a partial cross-sectional view of a liquid crystal display element showing a second embodiment of the present invention.

FIG. 8 is a sectional view of a part of a liquid crystal display element showing a third embodiment of the present invention.

FIG. 9 is a partial cross-sectional view of a liquid crystal display element showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 ... Back side substrate 2 ... Front side substrate LC ... Liquid crystal 3 ... Pixel electrode 4 ... TFT (Active element) 10 ... Gate line 11 ... Data line 12 ... Counter electrode 13 ... Insulating film 14R ... Red filter 14G ... Green filter 14B ... Blue filter 15 ... Solar cell 16, 18 ... Electrode 17p ... P-type semiconductor film 17n ... N-type semiconductor film 19, 20 ... Alignment film 21, 22 ... Polarizing plate 23 ... Insulating film 24 ... Black mask 25 ... Half mirror

Claims (9)

[Claims] 1. A liquid crystal comprising a solar cell provided on the inner surface of at least one of a front-side substrate and a rear-side substrate sandwiching the liquid crystal so as to correspond to a gap between pixels. Display element. 2. The display electrode on the side of the substrate on which the solar cell is provided,
The liquid crystal display element according to claim 1, wherein the liquid crystal display element is formed on an insulating film provided to cover the solar cell. 3. The solar cell is provided on the inner surface of the front surface side substrate, and the solar cell also serves as a black mask corresponding to a gap between each pixel. 2. The liquid crystal display element according to item 2. 4. A solar cell is provided with a first electrode formed on a substrate surface, p-type and n-type semiconductor films laminated on the first electrode, and formed on this semiconductor film. A second electrode, of the first and second electrodes,
4. The liquid crystal display element according to claim 3, wherein the electrode facing the light incident surface side of the liquid crystal display element is formed of a transparent conductive film, and the other electrode is formed of a light shielding metal film. 5. The liquid crystal display element according to claim 3, wherein the solar cell comprises a thick semiconductor laminated film in which p-type and n-type semiconductor films are laminated. 6. A color filter of a plurality of colors is provided on the inner surface of the front side substrate so as to correspond to each pixel, and a solar cell is provided between these color filters. Any one of claims 3 to 5
The liquid crystal display element described in 1. 7. The liquid crystal display element according to claim 1, wherein the solar cell is provided on the inner surface of the back side substrate. 8. A black mask corresponding to a gap between pixels is provided on the inner surface of the front surface side substrate, and a light incident surface of the solar cell faces a rear surface side of the liquid crystal display element. The liquid crystal display element according to claim 7. 9. A solar cell is provided on each of the inner surfaces of both substrates, and the light incident surface of the solar cell provided on the front surface side substrate faces the front surface side of the liquid crystal display element and is provided on the rear surface side substrate. The liquid crystal display element according to claim 1 or 2, wherein the light incident surface of the solar cell faces the back surface side of the liquid crystal display element.