Semiconductor module for power generation or light emission

In order to collect a plurality of semiconductor elements easily from a semiconductor module where a plurality of rod-like semiconductor elements for power generation or light emission are built in and to reuse or repair them, two split modules 61 are arranged in series in a containing case 62 in a semiconductor module 60. In each split module 61, power generating semiconductor elements 1 arranged in a matrix of a plurality of rows and columns, and a conductive connection mechanism for connecting the plurality of semiconductor elements 1 in each row in series and the plurality of semiconductor elements 1 in each column in parallel are molded with transparent synthetic resin, and a connection conductor 67 is allowed to project at the end. A conductive waved spring 70 and an external terminal 76 are provided on the end side of the containing case 62, and series connection of the two split modules 61 is ensured by mechanical pressing force of the conductive waved spring 70.

TECHNICAL FIELD

The present invention relates to a semiconductor module for power generation or light emission comprising a plurality of rod-like semiconductor elements having power generation or light emission capability and electrically connected in series and in parallel for high output.

BACKGROUND TECHNOLOGY

The inventor of the present application proposed, as set forth in the International Publication No. WO98/15983, a spherical semiconductor element having light reception or light emission capability and having positive and negative electrodes at opposite portions to each other with regard to the center and a solar battery module wherein a plurality of semiconductor elements are connected in series and two or more of the series-connected semiconductor elements are embedded in a synthetic resin material. The spherical semiconductor element has a spherical pn-junction in the surface part and the positive and negative electrodes are provided at the centers of the surfaces of p-type and n-type regions, respectively.

The inventor of the present application proposed, as set forth in the International Publication Nos. WO02/35612, WO02/35613, and WO03/017382, a solar battery module wherein the above described spherical semiconductor elements are arranged in a plurality of rows and columns and the semiconductor elements in each row are connected in parallel by conductive members and solder or conductive adhesive, the semiconductor elements in each column are connected in series by lead members and solder, and they are embedded in a synthetic resin material.

The inventor of the present application proposed in the International Publication No. WO02/35612 a rod-like semiconductor element having light reception or light emission capability wherein a cylindrical semiconductor crystal has a pair of end faces perpendicular to the axis, a pn-junction is formed near the surface of the semiconductor crystal containing one end face, and positive and negative electrodes are formed on either end face. The inventor of the present application proposed, as set forth in the International Publication No. WO03/036731, a semiconductor module having light reception or light emission capability wherein a plurality of semiconductor elements are embedded in a synthetic resin material.

In the photovoltaic array described in the U.S. Pat. No. 3,984,256, an n-type diffusion layer is formed on the surface of a filament consisting of a p-type silicon semiconductor having a diameter of 0.001 to 0.010 inch and a plurality of such filaments are arranged in parallel and in a plane. A plurality of P-connection wires and N-connection wires are arranged orthogonally and alternately on the top surface of the filament. The P-connection wires are ohmic-connected to the exposed parts of the p-type silicon semiconductors of the plurality of filaments and the N-connection wires are ohmic-connected to the n-type diffusion layers of the plurality of filaments. The plurality of P-connection wires are connected to P-buses and the plurality of N-connection wires are connected to N-buses. Highly strong insulating fibers are interwoven to form a mesh structure with the plurality of P-buses and N-buses, whereby a flexible solar battery blanket receiving the incident light from above for power generation is formed.

In the semiconductor fiber solar battery and module described in the U.S. Pat. No. 5,437,736, a molybdenum conductive layer is formed on the surface of an insulating fiber and two, p-type and n-type, photovoltaic thin semiconductor layers and a ZnO conductive layer are formed on the molybdenum conductive layer around approximately ⅗ of the periphery. A plurality of such semiconductor fiber solar batteries are arranged in parallel and in a plane, a metal coating is formed on the back, and the metal coating is partially removed in a specific pattern to form a connection circuit connecting in series the plurality of semiconductor fiber solar batteries.

Recently, solar batteries are increasingly used as a renewable, clean energy source in view of environmental issues such as air pollution and global warming and depletion of fossil fuel. Light emitting diodes are also increasingly used as an illumination source for saving energy and resources. Saving in materials and resources and less production energy consumption are becoming requirements.Patent Document 1: International Publication No. WO98/15983;Patent Document 2: International Publication No. WO02/35612;Patent Document 3: International Publication No. WO02/35613;Patent Document 4: International Publication No. WO03/017382;Patent Document 5: International Publication No. WO03/036731;Patent Document 6: U.S. Pat. No. 3,984,256; andPatent Document 7: U.S. Pat. No. 5,437,736.

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

When spherical or nearly spherical semiconductor elements are used to constitute a solar battery panel, the light receiving area per semiconductor element is small and therefore a larger number of semiconductor elements are necessary. Consequently, there are many connection points where the semiconductor elements are electrically connected and the conductive connection mechanism has a complex structure, leading to higher production cost. This also applies to the above described rod-like semiconductor element. The rod-like semiconductor element has an increased resistance between the electrodes for a generated current when it has a larger axial length. The axial length has to be approximately 1.5 times of the diameter or smaller and the light receiving area cannot be increased so much.

The photovoltaic array described in the U.S. Pat. No. 3,984,256 uses very fine silicon fibers. It is difficult to reduce production cost because of many electric connections. Light enters from above; there is no way to receive light entering the panel from the sides. This also applies to the semiconductor fiber solar battery described in the U.S. Pat. No. 5,437,736. Particularly, it is desirable for solar battery panels applied to window panes to be able to receive light entering them from the sides. On the other hand, when a light emitting panel is constituted using semiconductor elements having light emitting capability, it is desirable that light can exit from the sides.

In many prior art solar battery modules and light emitting diode displays, a large number of granular semiconductor elements are connected to conductive members using solder or conductive adhesive and the whole structure is embedded in a transparent synthetic resin cover case (outer enclosure). Therefore, the large number of semiconductor elements cannot be removed and recovered from the cover case when the solar battery module is disposed. Hence, it is difficult to recover and reuse semiconductor elements from disposed solar battery modules and light emitting diode displays and solutions giving consideration to resources and natural environments have been sought.

After the above described semiconductor elements are in practical use on a massive scale in the near future, they will be replaced or disposed accordingly in large numbers as a result of deterioration or the end of life-span. That may be a great burden to resources and natural environments. Particularly, regulations have been imposed on the use of lead-containing solder materials in them.

The purpose of the present invention is to provide a semiconductor module for power generation or light emission that is usable as a solar battery module or light emitting diode display in which a plurality of semiconductor elements having power generation or light emission capability are installed, to provide a semiconductor module for power generation or light emission that is easy to reuse, recycle, and repair a plurality of semiconductor elements, and to provide a semiconductor module for power generation or light emission in which semiconductor elements having a large light receiving or light emitting area are installed.

Means to Solve the Problem

The semiconductor module for power generation or light emission of the present invention is a semiconductor module comprising a plurality of semiconductor elements having power generation or light emission capability characterized in that the plurality of semiconductor elements each comprise a base consisting of a p-type or n-type rod-like semiconductor crystal having a circular or partially circular cross-section, separate conductive layer formed in a surface part of the base except for a band-shaped area parallel to an axis of the base and its vicinity and having a conductive type different from that of the base, a pn-junction formed by the base and separate conductive layer in a shape of a partial cylinder, a band-shaped first electrode ohmic-connected to a surface of the base at the band-shaped area, and a band-shaped second electrode ohmic-connected to a surface of the separate conductive layer on an opposite side of the axis of the base to the first electrode; a retention means retaining the plurality of semiconductor elements in a manner that they are arranged in a plurality of columns and rows in a plane with their conducting direction aligned in a column direction and they are separable individually or in groups is provided; a conductive connection mechanism connecting in series the plurality of semiconductor elements in each column or in each two adjacent columns of the plurality of columns and connecting in parallel the plurality of semiconductor elements of each row of the plurality of rows is provided; and conductive elastic members applying mechanical pressing force in a direction parallel to the column direction are provided for maintaining the series connection of a plurality of columns of semiconductor elements by the conductive connection mechanism.

The semiconductor module uses a rod-like semiconductor element having a rod-like base, a pn-junction in the shape of a partial cylinder, and first and second electrodes provided at the ends on either side of the axis of the base, thus increasing the light receiving area or light emitting area per semiconductor element and reducing the necessary number of semiconductor elements and the number of electric connections.

The conductive connection mechanism connects in series the semiconductor elements in each column or the semiconductor elements in each two adjacent columns and connects in parallel the semiconductor elements in each row. When some semiconductor elements fail due to defects or disconnection, the current flows through an alternative path bypassing the failed semiconductor elements. All normal semiconductor elements effectively work. In a solar battery module, when some semiconductor elements are disabled because they are in shade, the current flows through an alternative path in the same manner as the above. Also in a light emitting diode display, the current flows through an alternative path in the same manner as the above. All normal semiconductor elements effectively work.

The conductive connection mechanism has conductive elastic members applying mechanical pressing force in the direction parallel to the column direction for maintaining the series connection of a plurality of columns of semiconductor elements. Therefore, electric connection by solder or conductive adhesive can be minimized or eliminated. When the semiconductor module is disposed or repaired, the retention means can be disassembled to separate the plurality of semiconductor elements individually or in groups. The plurality of semiconductor elements can be removed individually or in groups.

The following various structures can be used in addition to the above structure of the present invention.

(1) The cross-section of the base of the semiconductor element in a plane orthogonal to the axis of the base is a partial circle obtained by removing from a circle a segment of which the chord is ½ to ⅔ of a diameter in length.

(2) The band-shaped area of the base is a band-shaped flat area formed by removing the segment having the above chord.

(3) The other conductive layer is a diffusion layer formed by diffusing an impurity.

(4) The retention means has a flat containing case forming a flat containing zone containing a plurality of semiconductor elements, the containing case comprises a plurality of separable members including a pair of casing plates separating the containing zone from the surroundings on either side, and at lest one of the casing plates is made of an optically transparent glass or synthetic resin.

(5) In the above (4), the retention means has a plurality of waved retention springs arranged nearly in parallel in the containing case and each consisting of a conductive strip, the plurality of semiconductor elements in each row are retained by a pair of waved retention springs with their first and second electrodes electrically connected to them, and the conductive connection mechanism comprises the plurality of waved retention springs.

(6) In the above (5), the plurality of semiconductor elements are retained between a plurality of troughs of one of adjacent waved retention springs and a plurality of crests of the other, respectively.

(7) In the above (6), the plurality of waved retention springs form a mesh structure with the plurality of semiconductor elements being retained.

(8) In any of the above (4) to (7), the semiconductor element is a semiconductor element having power generation capability and the pair of casing plates is made of an optically transparent glass or synthetic resin.

(9) In the above (4), the plurality of semiconductor elements are divided into a plurality of groups; the plurality of semiconductor elements in each group are arranged in a matrix of a plurality of rows and columns and adjacent semiconductor elements of the plurality of semiconductor elements in each row are placed closely or at a specific interval; the conductive connection mechanism has a plurality of conductive wires provided between rows of a plurality of rows of semiconductor elements and a pair of connection conductors provided outside the rows at either end in the column direction and in parallel to a row direction; and the plurality of semiconductor elements, plurality of conductive wires, and pair of connection conductors of each group are partially embedded in an optically transparent resin to form a flat split module.

(10) In the above (9), two or more of the split modules are arranged in the containing case in series in the column direction with the connection conductors of adjacent split modules being electrically connected.

(11) In the above (10), the containing case comprises a pair of casing plates superimposed face-to-face, the casing plates each have sidewalls closing both ends of the containing zone in the row direction and terminal mounting grooves extending from the containing zone to either end of the casing plate in the column direction, and a terminal plate protruding outside is mounted in a pair of facing terminal mounting grooves of the containing case and fixed to the containing case.

(12) In the above (11), waved springs constituting the conductive elastic members are interposed between the terminal plate and the connection conductor of split module facing the terminal plate, and the elastic biasing force of the pair of waved springs serves to maintain electrical series connection of a plurality of split modules.

(13) In the above (11) or (12), the terminal plates are fixed to the containing case in the manner that their positions are adjustable in the column direction.

Advantages of the Invention

The semiconductor module for power generation or light emission of the present invention uses a rod-like semiconductor element having a rod-like base, a pn-junction in the shape of a partial cylinder, and first and second electrodes provided at the ends on either side of the axis of the base, thus increasing the light receiving area or light emitting area per semiconductor element, reducing the necessary number of semiconductor elements and the number of electric connections, reducing the production cost, and realizing a semiconductor module having high power generation or light emission capability.

A retention means retaining a plurality of semiconductor elements in the manner that they are separable individually or in groups and conductive elastic members applying mechanical pressing force in direction parallel to the column direction for maintaining the series connection of a plurality of columns of semiconductor elements by the conductive connection mechanism are provided. Therefore, when the semiconductor module is disposed or repaired, the plurality of semiconductor elements can be removed individually or in groups. The semiconductor elements can be reused, recycled, or repaired. The prior art solder or conductive adhesive connection can be eliminated or minimized.

DESCRIPTION OF NUMERALS

BEST MODE FOR IMPLEMENTING THE INVENTION

The present invention relates to a semiconductor module for power generation or light emission comprising a plurality of rod-like semiconductor elements having power generation or light emission capability wherein the plurality of semiconductor elements can be separated individually or in groups when the semiconductor module is disposed or repaired.

A solar battery module of Embodiment 1 (which corresponds to the semiconductor module for power generation) will be described with reference toFIGS. 1 to 11. First, a rod-like semiconductor element having power generation capability and applied to the solar battery module will be described.

As shown inFIGS. 1 to 3, a rod-like semiconductor element1has a rod-like base2consisting of a p-type silicon monocrystal, a flat area3formed on the base2in the shape of a band or strip parallel to the axis of the base2, an n-type diffusion layer4, a pn-junction5formed by the base2and diffusion layer4in the shape of a partial cylinder, an antireflection film6, a positive electrode7ohmic-connected to the base2, and a negative electrode8ohmic-connected to the n-type diffusion layer4.

The cross-section of the base2in a plane orthogonal to the axis2ais of a partial circle obtained by removing from the circle (for example having a diameter of 1.8 mm) a segment of which the chord is ½ to ⅔ of the diameter in length. The base2has an axial length of for example 5 to 20 mm. The base2has at the bottom a flat area3in the shape of a band or strip extending over the entire length in parallel to the axis2aand having a width of for example 0.6 mm (which corresponds to the band-shaped area). The flat area3serves as a reference surface for positioning the base2, a surface for preventing the base2from turning over, and a reference surface for distinguishing between the positive and negative electrodes7and8.

The n-type diffusion layer4(which corresponds to the separate conductive layer) consists of an n-type semiconductor having a conductivity type different from that of the base2. The n-type diffusion layer4is formed in the shape of a partial cylinder close to a cylinder by thermal-diffusing an n-type impurity such as phosphorus (P), arsenic (As), and antimony (Sb) in the surface part of the base2to a depth of 0.5 to 1.0 μm except for the flat area3and its vicinity on either side. The pn-junction5is formed in the shape of a partial cylinder close to a cylinder near the boundary between the base2and n-type diffusion layer4.

The positive electrode7(which corresponds to the first electrode) is formed at the center of the flat area3in the shape of a band or strip extending over the entire length of the base2and having a width of for example 0.4 mm, and is electrically connected to the base2. The positive electrode7is formed by applying and firing a positive electrode material consisting of a silver-containing paste. The negative electrode8(which corresponds to the second electrode) is formed on the surface of the n-type diffusion layer4at a position opposite to the positive electrode7with regard to the axis2aof the base2in the shape of a band or strip extending over the entire length of the base2and having a width of for example 0.4 mm, and is electrically connected to the n-type diffusion layer4. The negative electrode8is formed by applying and firing a negative electrode material consisting of an aluminum-containing paste.

The antireflection film6consisting of a silicon oxide coating or silicon nitride coating and serving as a passivation film on the surface of the semiconductor element1is formed on the exposed surface of the base2and n-type diffusion layer4except for the areas where the positive and negative electrodes are formed.

In this semiconductor element1, the area of the pn-junction5is much larger than the cross-sectional area of the base2in a plane orthogonal to the axis2a.FIG. 3is a perspective view of the semiconductor element1seen from above. With sunlight bm entering the surface of the semiconductor element1except for the areas where the positive and negative electrodes7and8are formed and being absorbed by the silicon monocrystal of the base2, carriers (electrons and holes) are generated and the pn-junction5separates electrons from holes and approximately 0.5 to 0.6 V of photovoltaic power is generated between the positive and negative electrodes7and8.

The semiconductor element1has a rod-like shape close to a cylinder. The positive and negative electrodes7and8are provided on either side of the axis2aof the base2; the positive electrode7is placed at the center of the p-type surface of the flat area3and the negative electrode8is placed at the center of the n-type surface of the diffusion layer4. Therefore, light is received symmetrically about the plane connecting the positive and negative electrodes7and8. Sunlight in a wide range of directions can be absorbed on either side of the plane with high light reception sensitivity. The light reception sensitivity does not drop as the incident light direction changes.

As shown inFIG. 3, for carriers generated at different positions A, B, and C in the circumferential direction on any plane orthogonal to the axis2aof the base2as a result of the silicon monocrystal of the base2receiving sunlight, the sum of the distances to the positive and negative electrodes7and8is nearly equal, namely (a+b)≈(a′+b′)≈(a″+b″). Then, the photoelectric current distribution is uniform with regard to the axis2aof the base2and resistance loss due to uneven distribution can be reduced. Here, the pn-junction5is covered with and protected by the insulating antireflection film6at the periphery and at the end faces orthogonal to the axis2a.

The semiconductor element1has the positive and negative electrodes7and8in the shape of bands formed on the surface of the rod-like base2at opposite positions to each other with regard to the axis2a. Even if the base2has a large length/diameter ratio, the distance between the positive and negative electrodes7and8can be maintained smaller than the diameter of the base2. Therefore, the electric resistance between the positive and negative electrodes7and8can be maintained small and the photoelectric conversion performance of the pn-junction5can be maintained high.

Consequently, when a solar batter module is constituted using a large number of semiconductor elements1, the base2having a larger length/diameter ratio can contribute to reducing the necessary number of semiconductor elements1, reducing the number of electric connections, increasing the reliability of the solar battery module, and reducing production cost. The light reception symmetric about the plane containing the positive and negative electrodes7and8allows for a solar battery module that can receive light on both sides.

The base2has the flat area3, which serves as a reference surface in the course of production of the semiconductor element1, prevents the base2from turning over, and allows for example a sensor of an automated assembly apparatus to distinguish between the positive and negative electrodes7and8. The antireflection film6on the surface of the semiconductor element1reduces reflection of incident light and increases the light reception rate. The antireflection film6also serves as a passivation film, protecting the surface of the semiconductor element1and ensuring its durability.

A solar battery module20constituted by a large number of semiconductor elements1connected in series and in parallel will be described hereafter with reference toFIGS. 4 to 11.

The solar battery module20is a double glass solar battery module. The solar battery module20has a rectangular light receiving surface of for example 50 to 75 mm on a side. This light receiving surface size is given by way of example. Larger solar battery modules can be constituted.

As shown inFIGS. 4 and 5, the solar battery module20comprises a retention mechanism21(the retention means) retaining a plurality of semiconductor elements1in the manner that they are arranged in a plurality of columns and rows in a plane with their conducting direction aligned in the column direction and they are separable individually or in groups, a conductive connection mechanism22connecting in series the plurality of semiconductor elements1in each two adjacent columns of the plurality of columns and connecting in parallel the plurality of semiconductor elements1in each row of the plurality of rows, and a plurality of conductive waved retention springs23serving as conductive elastic members applying mechanical pressing force in the direction parallel to the column direction for maintaining the series connection of a plurality of semiconductor elements1by the conductive connection mechanism.

The retention mechanism21comprises a flat containing case24and a plurality of conductive waved retention springs23. The conductive connection mechanism22comprises the plurality of waved retention springs23. A flat, rectangular containing zone25is formed in the containing case24to contain the plurality of semiconductor elements1. The containing case24has an outer frame26surrounding the containing zone25and transparent glass casing plates27closing the top and bottom of the containing zone25and outer frame26.

The outer frame26is a rectangular frame made of an insulating member (a printed wiring board) made of glass fibers and an epoxy resin and having a thickness of approximately 2 mm. The outer frame26has at the right and left ends inFIG. 5vertical frame parts26aextending beyond the ends of the casing plates27.

As shown inFIGS. 5 and 8, the right and left vertical frame parts26ahave a plurality of slot/pore sets28to couple the coupling parts23cat the ends of the waved retention springs23. A conductive layer29consisting of a silver-coated copper foil is formed on the inner surface of the slot/pore set28. The conductive layer29is electrically connected to the coupling part23cof the waved retention spring23. The right and left vertical frame parts26ahas a plurality of lead connection parts30corresponding to the plurality of slot/pore sets28. Each lead connection part30consists of a silver-coated copper foil and electrically connected to the conductive layer29of the corresponding slot28.

As shown inFIGS. 5 to 10, a plurality of waved retention springs23are provided in the containing zone25in the manner that they are nearly in parallel and the troughs23aand crests23bof adjacent waved retention springs23closely face each other. The end and leading coupling part23cof each waved retention spring23is fitted in a slot/pore28of the vertical frame part26a, whereby the waved retention spring23is coupled to the vertical frame part26a. The waved retention spring23is formed by shaping a band or strip phosphor bronze plate having a thickness of approximately 0.4 mm and a width of approximately 1.9 mm in a periodic wave pattern and silver-plating the surface.

A plurality of semiconductor elements1are arranged in a plurality of columns and rows with their conducting direction aligned in the column direction in the containing zone25. The plurality of semiconductor elements1in two adjacent columns are arranged in a zigzag pattern. The semiconductor elements1are placed in positions where the troughs23aand crests23bof adjacent waved retention springs23closely face each other. The positive electrode7of each semiconductor element1is bonded and electrically connected to the waved retention spring23using a conductive epoxy resin. The negative electrode8of each semiconductor element1is pressed against and electrically connected to the waved retention spring23through the elastic pressing force from the waved retention spring23. Abutting against the inner surfaces of the horizontal frame parts26bof the outer frame26, the waved retention springs23at the ends in the column direction are in place.

A number of rod-like semiconductor elements1are retained by mechanical pressing force from a plurality of conductive waved retention springs23and electrically connected in the containing zone25. The plurality of semiconductor elements1in each two adjacent columns of the plurality of columns are electrically connected in series by the plurality of waved retention springs23and the plurality of semiconductor elements1in each row are electrically connected in parallel by a pair of waved retention springs23on either side thereof. The conductive connection mechanism22comprises the plurality of waved retention springs23. The mechanical pressing force applied by the plurality of waved retention springs23in the column direction maintains the series connection of the plurality of columns of semiconductor elements1.

The transparent casing plates27are attached to the top and bottom of the outer frame26and containing zone25to seal the containing zone25. The casing plate27(for example having a thickness of approximately 3 mm) has an elastic film31made of a transparent silicone rubber having a thickness of approximately 0.2 mm on one surface (on the inner surface). The pair of casing plates27sandwiches a set of semiconductor elements1and the outer frame26in the manner that their elastic films31makes contact them. The elastic film31has at the periphery an elastic film frame31ahaving an increased thickness of approximately 0.5 mm for improved sealing against the outer frame26. The bolt holes27aof the casing plate27and the bolt holes26cof the outer frame26are aligned and steel bolts34and nuts35are fastened with synthetic resin (for example fluorocarbon resin) washers32and steel disc springs33for sealing.

Here, the end waved retention springs23adjacent to the horizontal frame parts26bof the outer frame26are in mechanical contact with and retained by the inner surfaces of the horizontal frame parts26bthrough the pressing force of the waved retention springs23. However, the integration is not necessarily achieved by fastening the bolts34and nuts35. Any structure that allows the casing plates27, outer frame26, and plurality of waved retention springs23to which a plurality of semiconductor elements1are attached to be individually separable can be used.

The containing zone25can be vacuumed in a vacuumed container before the bolts34are fastened where necessary. Then, the vacuumed containing zone25is sealed by fastening the bolts34and nuts35. Alternatively, an inert gas such as nitrogen gas can be introduced in the containing zone25before it is sealed. In this way, a highly heat-insulated double glass solar battery module20can be obtained. To this end, the containing zone25preferably has a hermetically sealed structure.

As described above, a plurality of semiconductor elements1are retained between the two casing plates27by the outer frame26and plurality of waved retention springs23. The plurality of waved retention springs23retaining the plurality of semiconductor elements1form a mesh structure, creating proper openings for natural lighting and proper spaces. Therefore, the double glass solar battery module20is usable as a highly heat-insulated and sound-insulated lighting window.

The waved retention springs23and semiconductor elements1also serve as a spacer to keep a certain distance between the two casing plates27, thus improving the mechanical strength. A low-E double glass structure in which the surfaces of the casing plates27are coated with an infrared-reflecting film such as silver and tin oxide can be used for obtaining an improved heat-insulated window.

The double glass solar battery module20can be used alone or in combination with other solar battery modules20having the same structure to increase the size and accordingly the output by electrically connecting them using the lead connection parts30. For example, when a plurality of solar battery modules20are connected in parallel, they can be connected using all lead connection parts30of at least one of the vertical frame parts26a. When a plurality of solar battery modules20are connected in series, they can be connected using the lead connection parts30at both ends or at one end in the column direction.

In the double glass solar battery module20, incident light transmitted through the transparent casing plates27is absorbed by the rod-like semiconductor elements1and electric power according to the intensity of light energy can be generated. During this process, not only direct light but also light multiple-reflected by the waved retention springs23, casing plates27, and semiconductor elements1within the containing zone25is finally absorbed by the semiconductor elements1and converted to electric power. The layout of a plurality of solar battery modules20and the shape of the waved retention springs23can be modified to alter the natural lighting rate and external appearance for use in windows.

In the double glass solar battery module20, a plurality of semiconductor elements connected in parallel by a pair of waved retention springs23are connected in series to form a mesh-structured electric circuit36as shown inFIG. 11. The electric circuit36is a equivalent circuit to the solar battery module20and the semiconductors1are presented by diodes1A. Therefore, when some semiconductor elements1are open due to failure or some semiconductor elements1are electrically disconnected or some semiconductor elements1are disabled because they are in shade, the electric current flows through an alternative path bypassing the failed semiconductor elements1, whereby all other normal semiconductor elements1do not lose or reduce the power generation capability.

Effects and advantages of the above described solar battery module20will be described hereafter.

(1) The rod-like semiconductor elements1each have the positive and negative electrodes7and8on either side of the axis thereof. Therefore, if the semiconductor element1has an axis length two or more time larger than the diameter, the resistance between the electrodes for a generated current is constant. Then, this allows for increasing the length/diameter ratio, increasing the light receiving area, reducing the necessary number of semiconductor elements, reducing the number of electric connections, reducing the production cost, and realizing a semiconductor module20having a high power generation capability.

(2) The rod-like semiconductor elements1are mechanically strong. Therefore, they can well be electrically connected to the waved retention springs23by the pressing force of the waved retention springs23. Then, the solar battery module20can be disassembled simply by unfastening the bolts34and nuts35, whereby the plurality of semiconductor elements1(a set of semiconductor elements) attached to the waved retention springs23can easily be removed together with the waved retention springs23and so do the other parts. The plurality of semiconductor elements1removed together with the waved retention springs23can be reused as they are together with the waved retention springs23or separated from the waved retention springs23by melting the conductive adhesive. In this way, the recovery cost of semiconductor elements1can be much lower than the prior art where the semiconductor elements1are connected firmly using solder.

(3) The outer frame26, plurality of waved retention springs23, and two casing plates27are mechanically assembled using bolts and nuts. Therefore, the solar battery module20can easily be assembled/disassembled, leading to significantly reduced assembly/disassembly cost.

(4) With the semiconductor elements1and waved retention springs23being held between the two transparent casing plates27, the solar battery module20is highly mechanically strong and usable as a window material. Windows excellent in appearance can be obtained by well designing the layout of semiconductor elements1and the shapes and sizes of the waved retention springs23, outer frame26, and casing plates27. A light-reflecting curtain can be provided on the inner side of the window to reflect light from outside and illuminate the back of the semiconductor elements for improved power generation.

(5) When the solar battery module20is used as a wall or roof material besides the solar battery, the inner one of the two casing plates27can have a high reflectance coating on the inside surface or the inner casing plate27can be replaced with a highly reflective ceramic casing plate. When a ceramic plate is used, advantages include high mechanical strength and heat insurance although no natural lighting is available.

(6) The silicone rubber film31(the elastic film) effectively seals the clearance between the casing plate27and outer frame26and maintains the airtight state. When an inner gas is introduced or a vacuumed state is created, the silicone rubber film31is effective in preventing the semiconductor elements from deteriorating due to the ambient air or in improving the heat insulation of the double glass. The silicone rubber film31can be a film of other elastic transparent synthetic resins (such as EVA and PET).

Partial modifications of the above described solar battery module20will be described hereafter.

[1] The diameter of the base2of the semiconductor element1is not restricted to 1.8 mm. The diameter is desirably in a range from 1.0 to 2.0 mm; however, it is not restricted to this range. The width of the flat area3of the base2is not restricted to 0.6 mm and desirably approximately ½ to ⅔ of the diameter of the base2.

The semiconductor material of the base2is not restricted to a p-type silicon monocrystal and can be a p-type silicon polycrystal or other known semiconductors. The base2is not necessarily a p-type semiconductor and can be an n-type semiconductor. In such a case, the diffusion layer4forming a pn-junction together with the base2is a p-type semiconductor. In place of the diffusion layer4, separate conductive layer (the separate conductive layer having a conductivity type different from that of the base2) formed by CDV deposition or ion implantation can be used.

[2] The flat area3formed on the base2of the semiconductor element1is not essential for power generation. The flat area3can be eliminated. Then, the base2is circular in cross-section. A band-shaped area parallel to the axis where neither the diffusion layer4nor the pn-junction5is formed is created on the surface of the base2. A band of positive electrode7is provided on the band-shaped area at a position symmetric to the negative electrode8about the axis of the base and ohmic-connected to the base2.

[3] The outer frame26can comprise other materials such as ceramic wiring boards besides the above described epoxy resin printed wiring board. Ceramic wiring boards are expensive, but are fire resistant and excellent in mechanical strength and dimensional stability.

[4] The positive electrode7of the semiconductor element1can electrically connected to the waved retention spring23by pressing it using the elastic pressing force of the waved retention spring23without bonding it to the waved retention spring23using a conductive epoxy resin. In such a case, the semiconductor elements1can be removed individually when the solar battery module20is disassembled.

[5] One of the transparent casing plates27can have a reflecting film to reflect incident light for improved power generation by the semiconductor elements1. One or both of the two glass casing plates27can be replaced with a synthetic resin plate such as a transparent acrylic resin, polycarbonate resin, or silicone resin plate.

[6] The material of the waved retention springs23can be a known spring material such as carbon steel, tungsten steel, nickel steel, nickel silver, and beryllium copper or can be a piano wire.

[7] Circuit parts such as semiconductor elements or semiconductor chips other than the power generating semiconductor elements1, resistors, capacitors, and inductors can be mounted on the outer frame26to constitute a complex electronic function module or apparatus containing the semiconductor elements1. For example, a circuit to convert the direct current output of the solar battery module20to alternate current output and an output control circuit can be mounted. Furthermore, LEDs and batteries can be mounted other than the semiconductor elements1to constitute a display device in which the LEDs use the generated power to emit light. Alternatively, hybrid devices of the solar battery module and other functional apparatuses are available by installing optical communication light source LEDs or sensor elements and IC chips for external transmission of information.

[8] A light emitting diode module usable as a display or a surface light emitting illumination lamp can be constituted by replacing the above described semiconductor elements1with rod-like light emitting diode elements.

A solar battery module60of Embodiment 2 will be described with reference toFIGS. 12 to 17.

The solar battery module60is designed to integrate/disintegrate a plurality of power generating semiconductor elements1in groups, wherein a plurality of semiconductor elements1are divided for example into two groups to constitute two small flat split modules61and the two split modules61are installed and connected in series in a containing case62. The semiconductor elements1themselves are the same with semiconductor elements1in Embodiment 1 and the explanation will be made using the same reference numbers.

As shown inFIGS. 12 to 15, the solar battery module60comprises two split modules61and a containing case62forming a flat containing zone65containing the two split modules61. The split modules61are formed by fixing a plurality of semiconductor elements1arranged in a matrix of a plurality of rows and columns to a plurality of conductive wires66using a conductive adhesive to connect them in series and in parallel and molding the entire structure in a synthetic resin material61ato form a flat body. The retention means retaining the plurality of semiconductor elements1in the manner that they are arranged in a plurality of columns and rows in a plane and they are separable in groups comprises the synthetic resin material61aof the split module61and the containing case26.

The split modules61are arranged in series in the containing zone65of the containing case62and electrically connected to each other by the mechanical pressure from a pair of waved springs70(the conductive elastic members). In this embodiment, the solar battery module60having two split modules61is explained by way of example. However, the number of split modules installed in the containing case62is not restricted to two. The solar battery module60can have larger output as the number of split modules61is increased.

The above described split module61will be described hereafter.

As shown inFIGS. 13 and 16, a plurality of semiconductor elements1are arranged in a matrix of a plurality of rows and columns with their conducting direction aligned in the column direction (the transversal direction inFIGS. 13 and 16). Adjacent semiconductor elements1in each row are slightly spaced.

Fine conductive wires66having a rectangular cross-section are provided between adjacent rows of a plurality of semiconductor elements1and abut against their positive and negative electrodes7and8. Connection conductors67having a rectangular cross-section larger than the conductive wires66are provided to abut against the positive electrodes7or negative electrodes8of a plurality of semiconductor elements1in an either end row in the column direction. The positive and negative electrodes7and8of semiconductor elements1are bonded to the conductive wire66or connection conductor67using a known conductive adhesive (for example a silver epoxy resin) and heat-cured for firm fixing.

In this way, the plurality of semiconductor elements1in each row are connected in parallel by a pair of conductive wires66or a conductive wire66and a connection conductor67and the plurality of semiconductor elements1in each column are connected in series by the plurality of conductive wires66. The plurality of semiconductor elements1of the split module61are connected in series and in parallel by the plurality of conductive wires66and two connection conductors67. In this way, the split module61has a conductive connection mechanism64connecting in series the plurality of semiconductor elements in each column and connecting in parallel the plurality of semiconductor elements1in each row. The conductive connection mechanism64comprises the plurality of conductive wires66provided to the split module61. The conductive connection mechanism of the semiconductor module60comprises two conductive connection mechanisms64of two split modules61and two connection conductors67connecting in series the two split modules61.

The plurality of semiconductor elements1connected in series and in parallel, conductive wires66, and connection conductors67are entirely molded in a transparent synthetic resin (for example silicone resin) to form a flat body with the edges of the connection conductors67being exposed from the either end of the synthetic resin plate68. The synthetic resin plate68has flat retention parts68aat either end in the row direction.

A solar battery module60in which the above described two split modules61are installed will be described hereafter with reference toFIGS. 13 to 15. The containing case62is made of a transparent synthetic resin such as polycarbonate resin, acrylic resin, and silicone resin. The containing case62is formed by superimposing and bolting a pair of, top and bottom, casing members63having the same structure face-to-face. The casing members63each have a recess71forming approximately one half of the containing zone65and terminal mounting grooves72continued from either end of the recess71in the column direction.

The casing member63has a pair of lands73(sidewalls) outside the recess71. Approximately outer two thirds of the surface of the land73is covered with an elastic rubber, for example silicone rubber, coating74(for example having a thickness of 0.5 to 0.8 mm). The terminal mounting groove71also has the same rubber coating75on the inner surface. When the solar battery module60is assembled, the two split modules61are housed in the recess71of the bottom casing member63and covered with the top casing member63, whereby the retention parts68aof the split modules61at the ends in the row direction are interposed between the top and bottom lands73.

Then, waved springs70and conductive external terminals76are inserted in the flat terminal mounting openings consisting of the top and bottom terminal mounting grooves72at the ends in the column direction and rubber packing77is inserted between the external terminal76and containing case62. Then, the top and bottom casing members63are bolted and so do the top/bottom casing member and external terminals76. Here, for example, bolts78are inserted in bolt holes79and80with fluorocarbon resin washers78aand fastened to nuts78bwith underside fluorocarbon resin washers78a.

Here, the bolt holes80of the external terminals76are elongated in the column direction. Therefore, the bolt holes80can be used to adjust the fastening position of the external terminals76so that the waved springs70apply proper pressing force. In this way, the connection conductors76are in mechanical contact at the center of the solar battery module60and the two split modules61are electrically connected in series. The ends of the two split modules61are in mechanical contact with and electrically connected to the external terminals76via the waved springs70. Protruding at the ends of the containing case62, the external terminals76serve as the positive and negative electrode terminals of the solar battery module60. The power output can be retrieved from these positive and negative electrode terminals.

FIG. 17is an equivalent circuit83to the mesh structure of the solar battery module60. The semiconductor elements1are presented by diodes1A. The equivalent circuit83has the same effect as the equivalent circuit36of Embodiment 1. The electric power can be retrieved from the positive and negative electrode terminals81and82. Resin or rubber sealing members can be used to fill the clearance so as to seal the space where the split modules61are housed and block the ambient atmosphere.

In the solar battery module60, two split modules61are mechanically connected in series by the waved springs70in a common containing case62; their positions are secured by fastening the bolts78and nuts78band the rubber coatings74and75and packing77block the ambient air. The entire containing case62can be disassembled to replace or recover the split modules61for reuse. In this module60, the space within the containing case62has heat-insulation effect. If the casing members63are made of a synthetic resin, they are lighter, less breakable, and inexpensive compared with glass ones. If the semiconductor elements1are provided at a lower density, gaps are created and light is allowed to pass, whereby natural lighting is available when the module is used as a window.

Effects and advantages of the above described solar battery module will be described hereafter.

(1) The elongated rod-like semiconductor elements1allow for increasing a large length/diameter ratio of the semiconductor elements1, increasing the light receiving area per semiconductor element1, reducing the necessary number of semiconductor elements1, and reducing the number of electric connections, thereby reducing the production cost. The rod-like power generating semiconductor elements1allow for effective use of incident light in various directions for power generation. One or a plurality of solar battery modules60can be constituted as a window panel. In such a case, light from the room can also be used for power generation.

(2) The connection between the split modules61and the connection between the split module61and external terminal76are made by the mechanical pressing force of the waved springs70. There is no need of fixing by a bonding material such as solder. The split modules61, external terminals76, and waved springs70can easily be removed from the solar battery module60to use them for another solar battery module. Here, a plurality of solar battery modules60can easily be connected in series by contacting their external terminals76.

(3) The conductive waved springs70made of an elastic body assure the electric connection. They absorb dimensional changes (expansion or shrinkage) of the module in association with temperature changes and mechanical shocks and the semiconductor elements1are subject to no excessive stress.

(4) The column intervals of a plurality of columns of the split module61can be changed as appropriate and the thickness of the conductive wires66can be set on an arbitrary basis. Then, any proportion between natural lighting (see-through property) and power generation can be available and a panel consisting of solar battery modules60, light emitting diode modules, or their combination and also serving as a beautiful building material can be produced.

Partial modifications of Embodiments 2 will be described hereafter.

However, modifications with regard to the semiconductor element1are the same as those described for the above embodiment and their explanation is omitted here.

[1] The numbers of rows and columns of the matrix of a plurality of semiconductor elements1in the split module61are given by way of example. A split module can have larger numbers of rows and columns. The number of split modules61installed in the solar battery module60is not restricted to two and the number can be selected on an arbitrary basis. A plurality of split modules61can be arranged in a plurality of columns, not in a column, in the solar battery module60. In other words, a plurality of split modules61can be arranged in a matrix of a plurality of rows and columns in a solar battery module60. In such a case, the retention parts68aof the split module61can be omitted and the split module61can abut against the inner surface of the recess65.

[2] With regard to the external terminals76of the solar battery module60, it is advantageous for connecting in series a plurality of solar battery modules60that one of the external terminals76(for example the one on the positive electrode end) protrudes as shown in the figure and the other external terminal76(for example the one on the negative electrode end) is retracted in the terminal mounting opening and connectable to the one external terminal76(for example the one on the positive electrode end) of an adjacent solar battery module60.

[3] When the solar battery module60is constituted as a wall material that does not require natural lighting or see-through property, a light reflecting or light scattering plate or sheet can be provided behind the semiconductor elements1. Light transmitted between the semiconductor elements1is reflected behind the semiconductor elements1and increases the output of the semiconductor elements1in the solar battery module60. Light reflected forward increases brightness in a light emitting diode module.

[4] Applications include solar battery modules integrated into building materials such as roof, skylight, window, curtain wall, facade, eave, and looper, outdoor light emitting diode displays, and functional units for solar power generation or display or both as a part of advertising pillars, automobiles, aircraft, and boats.

[5] Various sensors, signal receiver, signal transmitter, AC/DC converter, frequency converter, logic circuits, and CPU and peripheral circuitry can be mounted on the lands73of the casing members63to control the input/output of the solar battery module or light emitting diode module.

A semiconductor element1A having light emission capability relating to Embodiment 3 is a rod-like light emitting diode. The semiconductor element1A can be installed in the semiconductor module20of Embodiment 1 in place of the semiconductor element1to constitute a semiconductor module for light emission. Alternatively, the semiconductor element1A can be installed in the semiconductor module60of Embodiment 2 in place of the semiconductor element1to constitute a semiconductor module for light emission.

The light emitting semiconductor element1A will be described hereafter.

As shown inFIGS. 18 and 19, the semiconductor element1A comprises a base2A, a flat area3A in the shape of a band or strip parallel to the axis2cof the base2A, a diffusion layer4A, a pn-junction5A, a negative electrode7A, a positive electrode8A, and a passivation coating6A. The semiconductor element1A has the same structure as the power generating semiconductor element1of Embodiment 1. The base2A consists of an n-type GaP (gallium phosphide) monocrystal or polycrystal and for example has a diameter of 0.5 mm and a length of approximately 5.0 mm. However, the diameter can be approximately 0.5 to 1.0 mm while the length is not restricted to 5.0 mm and can be larger than 5.0 mm.

A p-type diffusion layer4A and a pn-junction5A in the shape of a partial cylinder (a partial cylinder close to a cylinder) are formed by thermal-diffusing zinc (Zn) in the surface part of the base2A with a silicon nitride (Si3N4) diffusion mask placed on the flat area

3A and its vicinity on both sides in the same manner as the above described diffusion layer4. The pn-junction5A has an area larger than a cross-sectional area of the base2A in a plane orthogonal to the axis2a.

In the same manner as the above described antireflection film6, for example, a TiO2passivation coating6A is formed on the entire surface except for the areas where the positive and negative electrodes8A and7A are formed. In the same manner as the positive and negative electrodes7and8of the above embodiment, the negative and positive electrodes7A and8A are formed in the shape of a band or strip extending over the entire length. The negative electrode7A is provided on the flat area3A (a band-shaped area) at the center in the width direction and electrically ohmic-connected to the base2A. The positive electrode8A is provided at a position opposite to the negative electrode9B with regard to the axis2cof the base2A and electrically ohmic-connected to the p-type diffusion layer4A.

The light emitting semiconductor element1A (light emitting diode) emits red light from the pn-junction5A radially at nearly the same intensity when a forward current flows from the positive electrode8A to negative electrode7A. The light emission is symmetric about the plane containing the positive and negative electrodes8A and7A. The generated red light is emitted radially at the same intensity and with a wide range of directivity. Because the pn-junction6A is in the shape of a partial cylinder close to a cylinder, the generated red light crosses the surface of the semiconductor element1A at a right angle to exit outside. Therefore, the light is subject to less internal reflection loss and the light emission efficiency is improved. The distance between the positive and negative electrodes8A and7A can be maintained smaller than the diameter of the base2A. Then, the electric resistance between the electrodes8A and7A can be maintained low, yielding high light emission performance and light emission capability.

Partial modifications of the above described semiconductor element1A will be described hereafter.

The base2A can be constituted by various known semiconductor materials (such as GaAs, SiC, CaN, and InP) to constitute a semiconductor element1A emitting various lights. The separate conductive layer having a conductivity type different from the base2A and forming the pn-junction5A together with the base2A can be formed by thermal-diffusion, CVD deposition, or ion implantation of an impurity.

For example, a light emitting diode can be constituted by forming the base2A using an n-type GaAs monocrystal and forming the separate conductive layer as a diffusion layer obtained by thermal-diffusing Zn. Alternatively, a light emitting diode can be constituted by forming the base2A using an n-type GaAs monocrystal and forming the other conductive layer by thermal-diffusion, CVD deposition, or ion implantation of a p-type GaAs. Furthermore, a light emitting diode can be constituted by forming the base2A using an n-type SiC monocrystal and forming the other conductive layer by deposition of a p-type GaN or GaInP.

INDUSTRIAL APPLICABILITY

The semiconductor module for power generation or light emission of the present application can effectively used in solar battery panels, light emitting diode displays, and light emitting diode illumination apparatuses.