JP2008134661A - Reflective display with solar battery attached thereto - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflective display with a solar battery attached thereto with a solar battery function by supplementing the role of a color filter 50 or by having no loss of the role thereof in a reflective color liquid crystal display 2, especially having the color filter, which supplies itself with display driving power by the solar battery 30 formed on an information display surface. <P>SOLUTION: In the display with the solar battery attached thereto which comprises a light transmittance control layer 10, a selective reflection layer 22, and the solar battery 30, or the light transmittance control layer 10, the solar battery 30, and a reflection layer 20 sequentially from the observer's side K, the reflective display with the solar battery attached thereto has: the selective reflection layer 22 which is disposed on the front face of the solar battery 30 and which is constructed with an optical interference film reflecting only predetermined color light to the observer's side; and the color filter which is disposed on the rear side of the light transmittance control layer 10 and which is composed of three colors and a black matrix, wherein the black matrix and an electrode of the solar battery front face side are commonly used on the rear side of the reflection layer 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

 The present invention relates to a reflective display that supplies a part or all of display drive power by a solar cell formed on an information display surface, and more particularly, in a reflective color liquid crystal display, its color filter. It is related with the reflective display with a solar cell which supplements the role of or has a solar cell function without impairing.

 As a typical structure of a conventional flat-type image display, as shown in FIG. 6, light transmittance control for electrically controlling light transmission and light shielding using the polarization of light and the characteristics of a liquid crystal material. A light emitting layer (40) (commonly referred to as a backlight) is provided on the back surface of the liquid crystal as the layer (10).

 Moreover, in a display that displays information by color expression, a mask is applied to light having a broad spectrum distribution so that only light in a wavelength range required for the color arrangement pattern of each pixel can pass through from a light source to an observer. A color filter (50) is disposed somewhere in the light path.

 As shown in FIG. 7, the color filter (50) generally has a pixel pattern of three colors of red (R), green (G), and blue (B). When displaying information such as an image by splitting, a non-transparent pattern such as chrome called a black matrix (BM) is formed on the glass substrate (52) as means for sharpening the display.

 Of the three colored pixel patterns of the color filter (50), the light transmission spectrum of two or three colors has a distribution that does not overlap much in the visible light region, as shown in FIG. By controlling the voltage applied to the transparent electrode (12) made of ITO (Indium Tin Oxide) shown in FIG. 7 by controlling the orientation of the liquid crystal of the pixel, various full colors can be obtained at wavelengths in the visible light region (400 nm to 700 nm). Is to realize.

  Further, as a development of these conventional liquid crystal displays, an arc tube is arranged around the screen and the entire screen is illuminated from the back by an optical fiber. Instead of the arc tube, as shown in FIG. A display using a light emitting element (14) has been devised, but an electroluminescent light emitting element (14) is arranged over the entire screen and light is emitted by selectively passing an electric current. In this case, a low-voltage and high-efficiency self-luminous display is realized particularly when the organic electroluminescence light-emitting element (14) is used.

  On the other hand, what has been developed as a display with lower power consumption is a so-called reflective liquid crystal display. This does not have a backlight as the light emitting layer (40), and displays information such as images and characters on the screen by changing the reflectance of outside room light and sunlight from the outside. In addition to being able to display a natural display close to, it is not necessary to emit light by itself, so that it can be driven with relatively little energy.

10, 11 and 12 show an example of the structure of the reflective color liquid crystal display. A voltage is applied to the liquid crystal (16) as the light transmittance control layer (10) between the transparent electrode (12) made of ITO and the reflective layer (20) made of the aluminum reflector to change the light transmittance of each color. In the display shown in FIG. 10, outside light is reflected by the reflecting layer (20) made of an aluminum reflecting plate below the polarizing plate (54) and reflected by the observer. In the display shown in FIG. 11, a liquid crystal (16) called HAN liquid crystal is used as the light transmittance control layer (10), and only one polarizing plate (54) is required. In addition, in the display shown in FIG. 12, the reflective layer (20) made of an aluminum reflector below is designed to function as a liquid crystal electrode, and the surface is roughened to produce paper-like whiteness. Yes. The liquid crystal (16) used here is a ferroelectric and is called a guest-host liquid crystal, and once formed information can be held without consuming energy, and further low power consumption is considered possible. ing.

  However, even the reflection type liquid crystal display or electroluminescence display in the above-mentioned prior art, not only the display of its own information (voltage application to the liquid crystal) drive, but also a semiconductor arithmetic storage element such as an electric signal processing unit (CPU), etc. Drive and storage devices such as discs require a lot of power, and if used for a long time, you must carry a battery with a large volume or weight, which is a burden on the user. The usage time was limited due to the consumption of the battery.

  Moreover, even if it is only for the display unit, if it does not require a battery itself, it can be physically separated from the calculation unit, the storage unit, etc., and the installation of the display screen (display) is free. It is not difficult to imagine that the form of use of a device with a display can be remarkably free.

  Therefore, even when the solar cell (30) is applied to a reflection type display, there is a problem that an image cannot be displayed in a portion where the solar cell is formed, and the display screen is restricted. Furthermore, many photoelectric conversion layers used in the solar cell (30) are not transparent in the visible light region, and the reflective color liquid crystal display affects the color of information displayed when formed on the screen display unit. There is nothing else but to form a small area around the image display unit. In addition, although the solar cell (30) layer is formed on the back side from the light transmittance control layer (10) made of liquid crystal or the like, various solar cells have a unique color, so that they are used for, for example, a reflective color display. It was difficult.

 Furthermore, when the electrode for taking out the generated electric power is made in order to form the solar cell (30) on the back side from the light transmittance control layer (10), the color of the electrode itself affects the display screen and is accurate. There are problems such as difficult information transmission and image display.

  The present invention solves the problems of the prior art, and the problem is that a reflective display that supplies a part or all of the display drive power by a solar cell formed on the information display surface. In particular, an object of the present invention is to provide a reflective display with a solar cell that supplements the role of a color filter in a reflective color liquid crystal display having a color filter or has a solar cell function without being impaired.

  In order to achieve the above object in the present invention, first, in the invention of claim 1, information is visually given to an observer by a difference in brightness or color change between a plurality of periodically formed pixels, A reflective display that reflects ambient light on the viewer side and displays images and text information by absorbing or blocking light on paths before and after the light is reflected, and at least absorbing or blocking light from the viewer side In a reflective display with a solar cell configured in the order of a light transmittance control layer, a solar cell, and a reflective layer, a selective reflection layer is provided between the light transmittance control layer and the solar cell, and the selective reflection is performed. The layer is formed of an optical interference film or an optical multilayer film that reflects only a specific color toward the viewer side, and is a reflective display with a solar cell.

  According to a second aspect of the present invention, a conductive pattern is formed corresponding to an inter-pixel region of each pixel, and the conductive pattern itself is used as an electrode of a solar cell or a part thereof. 1 is a reflective display with a solar cell.

  According to a third aspect of the present invention, a three-color pattern of red (R), green (G), and blue (B) and a black matrix are provided on the back side (opposite the viewer side) from the light transmittance control layer. A color filter is provided, and a front side electrode of a solar cell is provided on the front side (observer side) of the selective reflection layer so as to at least partly have the same pattern as the black matrix. The reflective display with a solar cell according to claim 1 or 2.

  According to a fourth aspect of the present invention, the electrode on the back side is shared with the front side electrode of the solar cell among the electrodes used for electrical control to absorb or block light. 2. A reflective display with a solar cell according to 2.

  In the invention of claim 5, the average reflectance of light in the visible light region (wavelength 400 nm to 700 nm) in the selective reflection layer on the viewer side of the solar cell exceeds 50%, and the selective reflection layer The reflective layer with a solar cell according to any one of claims 1 to 3, wherein the reflective layer is shared as a front-side electrode of the solar cell.

  Further, in the invention of claim 6, by providing a solar cell function (photoelectric conversion function) only to a pixel region of one color or two colors among the three color arrangement patterns, light of a color arrangement pattern other than the above is used. The reflective display with a solar cell according to any one of claims 1 to 4, wherein the reflectance is assured.

  Furthermore, in the invention according to claim 7, a photoelectric conversion film for a solar cell is formed in which the light transmittance of the reflection region of the color arrangement is different from that of the other color arrangement portions for the one or two color arrangement pattern regions of the color filter. The reflective display with a solar cell according to any one of claims 1 to 3, wherein the reflective display has a solar cell.

  Furthermore, in invention of Claim 8, the said light transmittance control layer consists of a reflective liquid crystal display element or an electroluminescent display element, The reflective display with a solar cell of any one of Claim 1 to 7 It is a thing.

Since this invention is the above structure, there exist the following effects.
That is, from the observer side, at least a light transmittance control layer (liquid crystal or the like) that absorbs or blocks light, a selective reflection layer, a solar cell, a reflection layer or the light transmittance control layer, a solar cell, and a reflection layer in this order. In the reflective display with solar cell, the selective reflection layer disposed on the front surface of the solar cell is composed of an optical interference film or an optical multilayer film that reflects only a specific color toward the viewer. The selective reflection layer can also serve as a front-side electrode of the solar cell and have a function of transmitting light having a wavelength that can be converted into electric energy to the solar cell side on the back side.

  In addition, a color filter composed of a three-color pattern and a black matrix is disposed on the back side from the light transmittance control layer, and at least a portion of the black matrix on the front side (observer side) from the selective reflection layer. In particular, it has a solar cell front side electrode that has the same pattern, so that the reflective function with solar cell has a solar cell function without supplementing or impairing the role of the color filter in the reflective color liquid crystal display. Can provide a display.

 Furthermore, it is possible to provide a color filter having an electrode structure that does not impair the brightness and contrast of image display while forming a solar cell.

Hereinafter, embodiments of the present invention will be described in detail by way of specific examples.
The liquid crystal display and the electroluminescence (hereinafter abbreviated as EL) display relating to the reflective display with solar cell of the present invention are usually controlled for light transmittance between two glass substrates (52) as shown in FIG. In general, the liquid crystal (16) as the layer (10) is sandwiched. Of the two glass substrates (52), the glass substrate (52) on the viewer side (K) has a color arrangement pattern of red (R), green (G), and blue (B) and a black matrix. A filter (50) is disposed (the glass substrate (52) and the color filter (50) are collectively referred to as a color filter substrate (5)). However, in the case of a color EL display, a display that does not require a color filter can be configured by using EL materials having different emission colors.

 In addition, the solar cell (30) related to the reflective display with solar cell of the present invention includes a pair of semiconductors (N-type semiconductor (32), P-type semiconductor ( 34)), the front electrode (36) and the back electrode (38) for extracting power constitute the basic unit. Various semiconductors such as compound semiconductors, amorphous solar cells, and silicon single crystal solar cells have been devised depending on the semiconductor materials.

In the reflective display with a solar cell of the present invention, for example, as shown in FIG. 1, the substrate (52) on the back side (opposite to the observer side (K)) of the two glass substrates (52) described above. In addition, a solar cell (30) that reflects a part of the light in the visible light region is configured to create a reflective liquid crystal display (2) that supplements the power that it drives.
In particular, if a consumption electrode such as a reflective liquid crystal display or an organic EL display is extremely small, at least it can be applied as its own energy source and a display without an energy source can be configured.

 The solar cell (30) according to the present invention is characterized in that light having a wavelength longer than a specific wavelength determined by the material constituting the photoelectric conversion layer and the combination thereof cannot be converted into energy. Electric power is generated by absorbing light energy having a shorter wavelength than that of light and converting it into electrical energy. On the contrary, it has various colors according to the wavelength that becomes the limit of the conversion and the wavelength dependency of the conversion efficiency to the power of light. For example, a material in which amorphous silicon is used as the photoelectric conversion layer has light absorption (photoelectric conversion efficiency) as shown in FIG. 14, and therefore has a reddish brown color.

 If this photoelectric conversion layer material is used and a transparent electrode (12) made of ITO or the like is used on the front side of the solar cell (30) to form a reflective liquid crystal display (2) as shown in FIG. It is possible to create a reflective liquid crystal display with a solar battery that can display brightly at least for red and displays information in red and black. The reflective layer (20), which is a reflector on the back side of the solar cell (30), is made of chrome, silver, or the like to form a back electrode (38), and has a large light reflectivity at a wavelength at which photoelectric conversion can be performed with high efficiency. If this is provided, not only the incident light to the display but also the reflected light can be converted into electric energy, and a highly efficient solar cell can be constructed.

 In addition, as shown in FIG. 1, the solar cell (30) according to the present invention is formed on the front surface of the reflection layer (20) made of a reflector as shown in FIG. May be. For example, as shown in FIG. 1, when forming on the front surface of the reflective layer (20) made of this reflector, the front side electrode (36) on the observer side (K) of the solar cell (30) In addition to being able to use the transparent electrode (12) made of ITO or the like of the liquid crystal (16) as the transmittance control layer (10), the reflecting surface of the reflecting plate has a high reflectance of chromium, silver or the like. The reflective layer (20) needs to be formed, and can be shared with the back side electrode (38) of the solar cell (30). In this case, since the reflected light passes through the photoelectric conversion layer of the solar cell (30) again, the conversion efficiency can be further increased.

 As shown in FIG. 2, when the solar cell (30) is formed on the back surface of the reflective layer, the reflective layer also serves as the front electrode (36) of the solar cell (30) and is used for electric energy. It is necessary to provide a selective reflection layer (22) having a function of transmitting light with a wavelength that can be converted to the solar cell (30) side on the back side. In this case, this function can be supplemented by using a film capable of selecting a transmission wavelength region such as an optical interference film or an optical multilayer film as the selective reflection layer (22).

  The selection of a material for the selective reflection layer (22) capable of selecting a transmission wavelength region such as the optical interference film is well known and will not be described here because it is far from the gist of the present invention. Although there are various methods such as forming the reflective material by an optical interference film or an optical multilayer film, it is not described here for the same reason.

  As described above, if a solar cell is configured over the display screen that displays information, the power supply function can be achieved, and the formation can be performed on the display surface like a conventional solar cell. Is possible.

  Further, since it is not necessary to form the light receiving surface of the solar cell other than the reflective liquid crystal display surface, the entire surface of the card-type portable information processing terminal or the like can be used as a display.

 Furthermore, the reflective color liquid crystal display will be explained. When a solar cell is used, a reflective liquid crystal display that maintains sufficient color saturation and brightness can be configured by following the color pattern as follows. I can do it. That is, as described above, a film having a photoelectric conversion capability with respect to visible light has a unique color. For this reason, as shown in FIG. 3, each color (R, G, B) By configuring the solar cell (30) in accordance with the distribution of the color filter (50) having a pattern, it is possible to reproduce a desired color necessary for image display or the like.

 For example, FIG. 4 shows an example in which a solar cell (30) using amorphous silicon is formed only in the red (R) pattern portion of the color filter (50). When cds is used, yellow can be expressed because it absorbs a shorter wavelength than blue (B). Furthermore, a green (G) pattern can be formed by forming a film of a color material that absorbs red due to a pigment or the like in this portion.

  Thus, if the solar cell (30) is partially and selectively selected for each color (R, G, B) pattern, a wider area can be secured for the solar cell (30). In addition, it has the advantage of enabling more free color reproduction. Moreover, the photoelectric conversion film itself of the solar cell (30) plays a role of a color filter, and the back side electrode (38) of the solar cell (30) is used as the reflective layer (20), or by using a pigmented resist. The present invention is not limited by using a color filter together. Further, it is obvious that the material composition of the photoelectric conversion film of the solar cell (30) can be changed by following each color (R, G, B) pattern by a known technique such as a photolithography process.

 The wavelength region absorbed by the solar cell (30) is caused by the hand structure of the N-type semiconductor (32) and the P-type semiconductor (34) constituting the solar cell (30). It is possible to scan the color tone by changing the absorption wavelength of light by processing. In this case, the patterning of the pixels may be configured for each color using a photolithography process, or may be configured by dividing the atoms to be doped and the amount thereof into each pattern.

 Further, when the solar cell (30) is formed in the color filter (50), the black matrix (BK) that is already a constituent element of the conventional color filter can be employed as it is as the electrode of the color filter. Many black matrices used in current liquid crystal displays are composed of chromium. However, even if a material that does not transmit light at all, such as metallic chrome, is clear, if a transparent or translucent material is used on the viewer side, power can be generated even in this portion.

 Further, as shown in FIG. 5, it is clear that if the black electrode matrix (BM) portion is used as a trunk and the transparent electrode (12) is formed on the back or front of the transparent electrode (12), it functions as a power extraction electrode more efficiently. . It does not matter whether the transparent electrode (12) is formed on the front surface of the reflective liquid crystal display or a part thereof. If the width is wide, the light transmittance is somewhat limited. However, power extraction is electrically efficient.

It is explanatory drawing showing the reflective liquid crystal display with a solar cell which shows one embodiment of this invention in the cross section. It is explanatory drawing showing the reflection type liquid crystal display with a solar cell which shows other one Embodiment of this invention with the side cross section. It is explanatory drawing showing the reflective color liquid crystal display with a solar cell which shows one embodiment of this invention by the side cross section. It is explanatory drawing which represented the reflective type color liquid crystal display with a solar cell which shows other one Embodiment of this invention by the side cross section. It is explanatory drawing which represented the reflective color liquid crystal display with a solar cell which shows other one Embodiment of this invention in the cross section. It is explanatory drawing showing the conventional flat type image display display concerning this invention in the side cross section. It is explanatory drawing showing an example of the color filter concerning this invention in the side cross section. It is a graph which shows the transmission spectrum of the color filter concerning this invention. It is explanatory drawing showing the example of the conventional EL display concerning this invention in the side cross section. It is explanatory drawing showing the example of the conventional color liquid crystal display concerning this invention in the side cross section. It is explanatory drawing showing the other example of the conventional color liquid crystal display concerning this invention with the side cross section. It is explanatory drawing which represented the further another example of the conventional color liquid crystal display concerning this invention in the side cross section. It is a sectional side view which shows an example of the solar cell concerning this invention. It is a light absorption curve in an example of the photoelectric converting layer of the solar cell concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reflection type display with solar cell 2 ... Reflection type liquid crystal display with solar cell 5 ... Color filter substrate 10 ... Light transmittance control layer 12 ... Transparent electrode 13 ... MIM diode 14 ... Electroluminescence light emitting element 16 ... Liquid crystal 20 ... Reflective layer 22 ... Selective reflective layer 30 ... Solar cell 32 ... N-type semiconductor 34 ... P-type semiconductor 36 ... Front side electrode 38 ... Back side electrode 40 ... Light emitting layer 50 ... Color filter 52 ... Glass substrate 54 ... Polarizing plate BM ... Black matrix K ... Observer side

Claims (8)

  Information is visually given to the observer by the difference in brightness or color change of a large number of periodically formed pixels, the ambient light is reflected on the observer side, and the light is reflected on the path before and after the light is reflected. A reflective display that displays images and text information by absorption or shading, and is constructed from an observer side in the order of a light transmittance control layer that at least absorbs or shields light, a solar cell, and a reflective layer. In the reflective display, a selective reflection layer is provided between the light transmittance control layer and the solar cell, and the selective reflection layer is an optical interference film or an optical multilayer film that reflects only a specific color toward the viewer. A reflective display with a solar cell, comprising:   The reflective display with a solar cell according to claim 1, wherein a conductive pattern is formed corresponding to an inter-pixel region of each pixel, and the conductive pattern itself is used as an electrode of a solar cell or a part thereof. .   A color filter composed of a three-color pattern of red, green, and blue and a black matrix is disposed on the back side (opposite to the observer side) from the light transmittance control layer, and the front side from the selective reflection layer. The reflective display with solar cell according to claim 1 or 2, further comprising a front-side electrode of a solar cell that is at least partially in the same pattern as the black matrix on the viewer side.   The reflective display with a solar cell according to claim 1 or 2, wherein a back side electrode is shared with a front side electrode of a solar cell among electrodes used for electrical control of light absorption or light shielding. .   The average reflectance of light in the visible light region (wavelength 400 nm to 700 nm) in the selective reflection layer on the viewer side of the solar cell exceeds 50%, and the selective reflection layer is on the front side of the solar cell. 4. The reflective display with a solar cell according to claim 1, wherein the reflective display is used as an electrode. 5.   By providing a solar cell function (photoelectric conversion function) only to a pixel region of one color or two colors among the three color arrangement patterns, the light reflectance of the color arrangement pattern other than the above is ensured. The reflective display with a solar cell according to any one of claims 1 to 4.   The one or two color arrangement pattern areas of the color filter are formed by forming a photoelectric conversion film of a solar cell in which the light transmittance of the reflection area of the color arrangement is different from that of the other color arrangement portions. The reflective display with a solar cell according to any one of 1 to 3.   The reflective display with a solar cell according to claim 1, wherein the light transmittance control layer includes a reflective liquid crystal display element or an electroluminescence display element.

Images