US3827048A

US3827048A - Alpha-numeric character display device and method, whose characters are formed of light emitting diodes

Info

Publication number: US3827048A
Application number: US00384232A
Authority: US
Inventors: S Usui
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 1972-08-10
Filing date: 1973-07-31
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30

Abstract

An alpha-numeric character display device and method of making the same. The alpha-numeric characters are formed of a plurality of light emitting diodes mounted on a transparent base plate with their respective P-N junctions lying in planes perpendicular to the base plate and arranged in a pattern to exhibit selectively a plurality of individual display units. Energization selectively of different diodes is accomplished through a novel conductive lead pattern laid down in layers above and over the surface of the base plate, the conductive leads being separated from each other by a novel insulating arrangement which is produced in a novel manner.

Description

United States Patent i191 Usui [111 3,827,048 [4 July 30 1974 ALPHA-NUMERIC CHARACTER DISPLAY DEVICE AND METHOD, WHOSE CHARACTERS ARE FORMED OF LIGHT EMITTING DIODES Related US. Application Data [63] Continuation-impart of Ser. No. 320,720, Jan. 3,

Setsuo Usui, Kanagawa-ken, Japan [30] Foreign Application Priority Data Aug. l0, i972 Japan 47-80110 [52] US. Cl. 340/366 R, 340/166 R [51] Int. Cl. 60% 5/00 [58] Field of Search 340/336 B, l66 R, 324 M; 3l3/l08 D, 336 R [56] References Cited UNITED STATES PATENTS 3,388,292 6/l968 Burns 340/324 M Primary Examinerl-larold l. Pitts Attorney, Agent, or Firml-lill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson 5 7 ABSTRACT An alpha-numeric character display device and method of making the same. The alpha-numeric characters are formed of a plurality of light emitting diodes mounted on a transparent base plate with their respective P-N junctions lying in planes perpendicular to the base plate and arranged in a pattern to exhibit selectively a plurality of individual display units. Energization selectively of different diodes is accomplished through a novel conductive lead pattern laid down in layers above and over the surface of the base plate, the conductive leads being separated from each other by a novel insulating arrangement which is produced in a novel manner.

12 Claims, 26 Drawing Figures PATENTED JUL30 I974 3,827, 048

SHEET 1 0F 8 PATENTED M 4 BM I. 048

sum 5 or a Fig. 18

PATENTEnJummu sum a or a ALPHA-NUMERIC CHARACTER DISPLAY DEVICE AND METHOD, WHOSE CHARACTERS ARE FORMED OF LIGHT EMITTING DIODES RELATED APPLICATIONS BACKGROUND OF THE INVENTION The underlying basic design of an alpha-numeric character display device is now well known, as witness the advent of electronic calculators. A common form of such a device is an evacuated tube containing an ionizable gas, such as neon. Each character is made up of 7 cathode segments in the form of a figure 8. A plurality of such characters are formed on a single tube and are selectively caused to glow to display the character desired.

Devices of the above type have had a disadvantage in that the amount of light which can be emitted from a compact structure is relatively small. The depth of the display device is also a critical factor in the adaptation of the device for its intended use.

In my copending application, Ser. No. 320,720, I have disclosed an alpha-numeric display device which employs light emitting diodes to form the alphanumeric characters, the diodes having P-N junctions lying in planes perpendicular to a transparent base plate on which they are mounted.

Light emitting diodes are known. The emitted light from such a diode comes from hole-electron recombi-' nations. In a solid-state light-emitting diode the supply of higher energy electrons is provided by forward biasing the diode, thus injecting electrons into the N region (and holes into the P region). The injected holes and electrons then recombine with the majority carriers near the junction. The recombination radiation is then emitted in all directions.

Light emitting diodes have been used in alphanumeric character display devices, and one such structure is disclosed in Electronics, May 1 l, 1970, pages 88 to 93.

In an alpha-numeric character display device of the present invention, the width of the light emitting diodes determines the width of the lines defining the segments of the design. This enables an extremely fine line pattern to be obtained.

BRIEF SUMMARY OF THE INVENTION The present invention provides a novel method of mounting light emitting diodes on a transparent base plate forming the conductive leads to the different diodes, and a novel display device structure.

In a first'preferred form of the present invention, a conductive wire pattern which corresponds to the contact terminals of the electronic parts, such as a light emitting diode or a transistor, is formed on a first glass plate. Thereafter, a first insulating resin layer is formed on the conductive wire pattern layer. Predetermined parts of this resin layer are removed in order to hold the electronic parts.

The electronic parts are inserted into etched recesses and then a photo sensitive resin is coated on both the electronic parts and the first resin layer so that the electronic parts are temporarily fixed to the conductive pattern layer. Thereafter, the electronic parts are completely fixed by a photo sensitive adhesive resin which is poured between the electronic parts and the first glass plate and the conductive pattern layer.

After that, a second insulating resin is formed on the first insulating resin layer through the photo sensitive resin layer which is utilized to fix temporarily the electronic parts. However, this second resin layer is removed in predetermined places, such as the connection point between the contact terminal of the electronic parts and the conductive pattern layer, and also an outer lead terminal.

Then, a conductive resin is poured into the above mentioned connection point and into the outer lead terminal.

Finally, a second glass plate having a reflective layer is adhered to the second insulating layer, which reflective layer effectively reflects light to the outside through the above photo sensitive adhesive resin and the first glass plate.

It is an object of the present invention to provide a novel alpha-numeric character display device employing a light-emitting diode for each segment of the display.

It is a further object of the present invention to provide an alpha-numeric character display device employing light-emitting diodes having a novel integrated circuit connecting the ohmic contacts of the various diodes.

It'is still another object of the present invention to provide a novel alpha-numeric character display device employing a fine line light source for each indicating line of the device.

It is another and further object of the present invention to provide a novel alpha-numeric character display device having a high degree of brightness.

A still further object of this invention is to provide a novel alpha-numeric character display device which is economical to manufacture and which is rugged and reliable in use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric diagrammatic view of a light emitting diode as employed in one preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of a conductive layer before forming the lead pattern as employed in the present invention;

FIG. 3 is a plan view of the upper surface of a portion of the transparent plate after forming the lead pattern thereon;

FIG. 4 is a cross-sectional view taken on line IVIV in FIG 3;

FIG. 5 is a plan view of the plate coated by the first insulating resin layer over the conductive layer;

FIGS. 6 and 7 are a cross-sectional and a perspective view, respectively, corresponding to FIG. 5;

FIG. 8 and FIGS. 10 to 17 show in a sequence of diagrammatic sectional views the formation of an alphanumeric character display device embodying a preferred form of the present invention;

FIG. 9 shows a photo mask pattern employed in the manufacture of the device, which overlies the first insulating resin layer;

FIG. 18 is a fragmentary cross-sectional view of the commencement of the formation of a second preferred embodiment of the present invention and shows a substrate glass plate supported in spaced relation on a base glass plate;

FIG. 19 is a view of the conductive pattern laid down on the glass substrate of FIG. 18;

FIG. 20 is an enlarged view of a portion of FIG. 19;

FIG. 21 is a view of a second pattern of insulating material coated on the first conductive pattern, with pockets for receiving the diodes;

FIG. 22 shows the light emitting diodes of two character units mounted in place with a third conductive resin layer mounted on the second layer;

FIG. 23 is a fragmentary isometric view of a portion of FIG. 22;

FIG. 24 shows a conductive paint poured onto the third resin layer and into the cavities;

FIG. 25 shows the upper portion of the conductive pattern having been selectively blasted away; and

FIG. 26 shows the resulting product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made to the first preferred embodiment of the present invention.

In FIG. 1 of the drawings, there is shown therein a lightemitting diode 1 having a P-N junction formed between a P-type region 2 and an N-type region 3. This diode is preferably made, for example, of gallium phosphide, silicon carbide or gallium nitride. The diode l is preferably made by cutting a semiconductor wafer with a diamond saw.

Ohmic contacts

4 and 5 are formed on the P-type and N-

type regions

2 and 3 respectively.

By way of example, and not by way of limitation, it has been found that the following dimensions for the diode are particularly effective. The thickness dimension a of the P-type region is preferably 50 to 100 microns with 80 microns being particularlysuitable. The thickness dimension b of the N-type region is preferably between 200 and 300 microns with 250 microns being particularly suitable. The maximum thickness dimensions c and d of the ohmic contacts are preferably of the order of 1,000 Angstroms. The length dimension e of the light emitting diode is preferably approximately 2 millimeters. The width dimension f is preferably approximately 50 to 100 microns.

The ultimate product is a device which includes a number of alpha-numeric character units mounted in a common plane which are arranged to be individually selectively energized. Each character unit is made up of nine diodes, seven of which are in a conventional figure 8 pattern, while the two additional diodes are for a decimal point and a dash. One electrode of all diodes of a single character unit are electrically connected together through a first conductive lead. The other electrode of each diode of a single unit is separately connected to a different second conductive lead, there being nine second conductive leads, one each diode of the character unit. All correspondingly located diodes of each character unit are connected together through their respective associated leads. The commonly connected electrodes of each character unit have a separate terminal for each character unit. This will be more fully understood when the second embodiment of the present invention is described in connection with FIG. 19.

The method of making the first embodiment will now be described. Referring first to FIG. 2, a glass plate 6 is dipped in Cr So liquid for 24 hours and then the glass plate 6 is washed with water and with acetone.

After that, as shown in FIG. 2, an aluminum layer 7 (approximately 2p. thick), an aluminum-copper alloy layer 8 (about 0.5 to 1.0 p.) and a copper layer 9 (about By.) are, in turn,.deposited on the glass plate 6 by any well known vapor evaporation method. The thickness of all the deposited metal layer is preferably more than 5p. so that, in the final process of the manufacture of this device, the lead frame is connected to the metal layer firmly by solder.

The AI-Cu alloy layer 8 and the relatively thick Al layer 7 helps to produce the high resolution of the lead wire pattern on the glass plate 6 during the etching process. Moreover, the relatively thick Al layer 7 adheres more firmly to the glass layer 6 than would copper, and accordingly, this avoids the so-called side etching.

This glass plate 6 with the metal layers is kept in the open air for about 24 hours at 40C and then it is baked for about 2 hours at C in order to cause better adherence. of the respective layers to each other.

In the next step, on the surface of the deposited layer 9, a photo resist is deposited by about 1p. thickness. Any suitable photo resist may be used such as that available under the trademark AZ-l350I-I. This photo resist is pre-baked for 30 minutes at 90C, and then is exposed by using a mask which has a predetermined conductive pattern. This exposure time is for about 2 to 3 minutes under thousand Iux.

The pattern etching may be done by the next few steps. At first, the Cu layer 4 is completely etched in liquid composed of I-INO H O 1:1 (30 to 35C) for 45 to 50 minutes. This etching speed is selected at B t/min. After washing the plate with water, the above resist layer is removed by acetone, for example. This etched copper pattern layer is utilized as an etching mask for the Al layer 8. The Al layer 8 is etched in a mixed liquid of NaOH (or KOI-I) H O 2001 for 5 to 10 minutes at 20C. This speed is suitable at l t/min. The Al-Cu alloy layer 8 may be etched during the etching process of the Cu layer 9 and the Al layer 7 simultaneously. After etching the above, the plate is washed by water and acetone, and then dried.

Referring to FIG. 3, there is shown thereon a conductive pattern layer 10 on the glass plate 6. The conductive pattern layer 10 comprises a plurality of segments 11 to 20 with the conductive pattern 20 providing a common electrode.

Light emitting diodes will be set in the gaps 21 to 29 located between the segments 11 to 19 and the common conductive segment 20. As shown in FIG. 3, this display shape is a well known Figure 8 type with a decimal. point and a dash. The terminal tabs for the various conductive segments are indicated with the respective numeral of each tab coupled with a prime.

FIG. 4 shows a cross-sectional view taken on the line IIA'-IIA' in FIG. 3 and shows the position of representative

conductive segments

16 and 20 on the glass substrate.

In the next step, a first insulating resin layer 30, which serves to hold the light emitting diode is formed on the glass plate 6 and the conductive layer 10 as shown in FIG. 6. In forming this first insulating pattern 30, as shown in FIGS. 5, 6 and 7, the portion on which the light emitting diode is held should be uncovered, and the outer conductive connection points 11 to 2.0 are also uncovered. It is very important that the conductive segments 11 to 20 be contacted with the light emitting diode around the center portion thereof, because, effectively, the concave portion of the resin layer 30 serves to holdthe light emitting diodes.

FIGS. 6 and 7 show a cross-sectional view and an isometric view taken along the line VIVI of FIG. 5. A recess 31 will support the light emitting diode. The above photo sensitive resin 30 available under the trade name SONNE 1027 or SONNE X-l 11" may be colored by a dye such as a blue color, for example. This color density is selected so that the resin 30 becomes hard by a predetermined light strength and further the resin 30 serves as an optical isolator. The thickness of this resin layer 30 should be the same thickness as the light emitting diode 1.

In the manufacture of the photo resin layer 30, this resin is poured on the plate 6 which has the conductive pattern segments 10, and then the glass photo mask is contacted to the poured resin layer through the polyester film (transparent). This polyester film may be firmly contacted to the poured resin by alcohol. In order to make this photo resin layer 30, the exposure is done under approximately 100 thousand lux for 3 minutes. After the exposure, this plate is washed by using an ultrasonic wave in N-Butyl alcohol. Thereafter, the plate is rinsed by ethyl-ether and is dried.

Referring to FIG. 8, the light emitting diode 1 is mounted in the recess 31 so that the P-N junction thereof is faced the glass plate 6. This step of inserting the diode 1 in the recess 31 is easy and has high reliability since the recess 31 serves as a holder or supporter for the diode.

After mounting the diode 1, it is temporarily fixed by the next step. First of all, on whole surface of the plate 6 is coated with a photo-sensitive resin available under the trade name SONNE KPM 1027 (a transparent material). Then, this resin is exposed by using the pattern mask 32 which is composed of mask portions 33 and a non-mask portion 34. Accordingly, the only area which corresponds to the non-mask portion 34 of the mask 32 becomes hard.

FIGS. 10 and 11 show a resin layer 35 which serves to fix the diode 1 temporarily.

Thereafter, as shown in FIG. 12, a transparent photosensitive resin 36, (KPM 1027), is poured on the upper surface. By the evacuation of air under the diode 1, the resin, KPM I027, penetrates between the glass plate 6 and the diode l.

The terminal tabs 11' through 19 are electrically connected to parallel extending conducting strips laid down in grooves in the locations indicated as 11" through 19", respectively, in FIG. 9, the grooves for conducting strips 15" through 18" being shown in FIG. 11.

As shown in FIG. 12, a polyester film 37 is contacted with the resin layer 36 so as to minimize some unwanted shapes after the exposure which is done in the next step.

Moreover, a mask 38 which covers the lead connection points 11 to 2l' is formed on the back of the glass plate 6, as shown in FIG. 12. Therefore, since light beam 39 is radiated from the underside of the glass plate 6, only the part of the resin which is under the diode I is hardened. Namely, both the mask 38 and conductive pattern 10 provide mask effects.

As a result, the diode 1 is firmly fixed to the glass plate 6. As one of the merits of this invention, since this resin 39 is filled into the gap 26, there is no concern that the conductive resin penetrates into the gap 26 during the next steps. In other words, each of the conductive layers 20 are completely isolated from each other.

After removing the polyester film 37, a photo sensitive resin, such as KPM 1027 (a transparent material) is poured. This resin, after the evacuation of air, is exposed by using a photo mask similar to the mask 32 shown in FIG. 9. This exposed resin is washed by using an ultrasonic wave and then the plate is exposed for 10 minutes.

Consequently, as shown in FIG. 13, this resin layer 40 uncovers only the connection points between the conductive pattern 10 and the

electrodes

4 and 5, and also uncovers the outer lead connection point 16'.

After that, a conductive resin 41, such as AHOMEX- AG or EPOTEK H3 1' (trade name) for example, is coated on the plate by a brush and heated at approximately to C for about 1 hour (FIG. 14).

The conductive resin layer 41 is selectively removed by sand-papering, as shown in FIG. 15. Thus, the

electrodes

4 and 5 are electrically connected to the conductive layer 10 by the conductive resin 41, and moreover, the conductive layer 10 is electrically connected to the conductive resin 41 in a recess 42 which is to be connected to outer leads (not shown).

As the final step, as shown in FIG. 16, a glass plate 43 having a reflective layer 44 is adhered, and finally, it may be mounted on a predetermined lead frame. This reflective layer 44 effectively reflects the light produced by the diode l to the outside through the window 39 and the glass plate 6.

It will be understood that when a predetermined voltage bias is supplied across the electrodes of the diode shown in FIG. 16 through the conductive leads l6 and 20, light is emitted from the P-N junction of the diode 1 Since the recess 31 is provided in the first resin layer 30, the diode 1 is easily inserted into its desired position and, accordingly, there is no misalignment of the diode Since the conductive pattern layer 10 is formed on nearly the whole area of the glass plate 6, this pattern layer 10 serves as a photo mask to make the hard resin layer 39 on which the diode 1 is fixed.

In order to fix the diode l, the photo mask 32 which is the same as the mask to form the second resin layer 40 is commonly used in two steps during the manufacture.

Since the resin 39 for fixing the diode l is poured into the gap 26 before coating of the conductive resin 41, any undesirable short circuit between the

conductive layer

16 and 20 is avoided.

A modified form of the preferred embodiment of the present invention will now be described with reference being had to FIGS. 18 to 26.

It starts, as did the first embodiment, by laying down a conductive layer on a glass plate 6. The conductive layer is preferably a composite layer 7 of aluminum, a layer 8 of aluminum-copper alloy, and a layer 9 of cop-' per. In the alternative it may be only a single layer of copper (see FIG. 18). The glass plate 6 is then secured in spaced relation to a support plate 45 by tacks of glue 46.

The conductive layer, whether it is a composite layer or a single layer, will hereinafter be referred to'as conductive layer 9. This layer is now etched to form the conductive pattern shown in FIG. 19. It will be noted that there are eleven tabs or terminals 47 to 57 along the lower side, one for each alpha-numeric character unit. There are eleven tabs or terminals 58 to 68 along the upper side, only tabs 59 to 68 being used.

Each of the eleven character units shown in FIG. 19 is made up of nine diodes. The conductive pattern for the two character units located above

tabs

56 and 57 are shown as a fragmentary greatly enlarged view in FIG. 20.

Let it be assumed that the anode electrodes of the diodes are to be selectively connected respectively to the tabs 47 to 57. The cathode electrodes of the diodes would then be selectively connected as hereinafter to be described to the tabs 59 to 67. When one of the tabs 47 to 57 is connected to a potential source the anodes of all of the diodes in the one character unit associated with such a tab are energized. What diodes radiate light, however, depends on which diodes have their cathode electrodes connected to the negative side of the potential source. Since there are nine diodes for each character unit, and hence nine cathodes, the cathodes of all similarly located diodes may be connected to a common conductive lead, there being one lead for each terminal tab 59 to 67. These conductive leads are located along paths 69 to 77 running parallel to the length of the device as indicated by the dash-dot lines in FIG. 20. They lie in a plane, however, above the plane of the conductive pattern and separated therefrom by suitable insulating material.

Referring to FIG. 20, but in a manner later to be brought out, the cathode electrode of each diode representing dash is connected to lead 69. The cathode of each diode forming the middle horizontal bar of each character is connected to lead 70. The cathode of the diode of each character forming the top bar is connected to lead 71. The cathode of the diode of each character forming the top right hand vertical bar is connected to lead 72. The cathode of each diode forming the top left hand vertical bar is connected to lead 73'. The. cathode of each diode forming the lower right hand vertical bar is connected to lead 74. The cathode of each diode forming the lower left hand vertical bar is connected to lead 75. The cathode of each diode forming the bottom horizontal bar is connected to lead 76. The cathode of each diode forming a decimal point is connected to lead 77.

It will be obvious from the above that it is necessary to separate the connective leads 69 to 75 except at certain desired connection points. The manner in which this is done will now be described.

Over the conductive pattern of FIG. 19 there is deposited an insulating layer 78 with the portions thereof at which the light emitting diodes are to be supported removed and with the portion thereof at the outer lead terminals also removed. See FIG. 21. The insulating layer 78 has nine windows 79 to 87 for each character through which connections will later be made to subsequently form leads 69 to 77 respectively. The portions of the layer 78 removed for receiving the diodes from pockets 88 to 96 for each character, as shown in FIG. 21. The diodes are mounted in place in the pockets 88 to 96.

The next step is to form a third layer 97 of insulating material on layer 78. The upper surface of this insulating layer is provided with grooves along lines 69 to 77 (see FIG. 22). The conductive leads can then be buried therein. The second insulating layer 97 provides a sea] at the edge of the pocket.

Now on the insulating layer 97 and on every diode a conductive paint layer 98 is coated (FIG. 24). Thereafter, a portion of the thickness of the layer 98 is removed as shown in FIG. 25. This completes now the connections between the conductive pattern layer and the conductive leads.

The substrate glass 6 is now removed from the base support 45. The glass plate 6 is then cut and a lead frame having solder plated layer therein is connected by heating.

It will be apparent to those skilled in the art that many modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

1. In an alpha-numeric character display device composed of a plurality of similar display units, each having a plurality of light emitting diodes similarly arranged in a display array to be selectively energized to depict different desired characters, the combination comprising a transparent glass base plate, a conductive layer pattern formed on said base plate having individual paths for one side of each diode of each display unit and having a common path for the other side of all diodes in one display unit but separate paths for different units, a plurality of parallel disposed conductive leads corresponding in number to the total number of diodes in a single display unit running lengthwise of said device in a plane above said conductive pattern, the first side of all similarly located diodes of the different display units being electrically connected together through said conductive leads and said conductive layer pattern, there being one conductive lead for each group of similarly located diodes, and a terminal for each conductive lead and a terminal for each common path to said other side of the diodes of each display unit.

2. An alpha-numeric character display unit comprising a transparent non-conductive plate, a conductive layer on one surface of said plate shaped in a predetermined pattern, said pattern including separated seg ment portions spaced to form a seven arm figure 8 configuration with pairs of said segment portions on opposite sides of said arm locations, and separate segment portions forming the other side of the arm locations, the segment portions forming one side of each arm location being commonly connected, a terminal for said commonly connected segment portions, separate subterminals for each said other segment portion, separate lead conductors for the segments forming the other side of each arm location respectively, first insulating layer means covering said conductive layer except for pockets opposite said arm locations, a light emitting diode in each pocket having anode and cathode electrodes having their respective pn junctions in planes perpendicular to said plate, said electrodes being in abutting electrical contact respectively with segment portions on each side of said arm locations, a second insulating layer covering said first insulating layer and said diodes, said second insulating layer having grooves in the upper surface thereof in which said lead conductors are disposed, said insulating layers having windows therethrough below each lead conductor opposite a different sub-terminal respectively, a conductive material filling each of said windows and connecting each of said lead conductors with its associated sub-terminal, and a third insulating layer covering said second insulating layer.

3. An alpha-numeric character display unit, comprising a transparent non-conductive plate, a conductive layer on one surface of said plate shaped in a predetermined pattern, said pattern including separated segment portions spaced to form a seven arm figure 8 configuration with pairs of said segment portions on opposite sides of said arm locations, the separate segment portions formingthe other side of the arm locations, the segment portions forming one side of each arm location being commonly connected, a terminal for said commonly connected segment portions, separate subterminals for each said segment portion, separate lead conductors for the segments forming the other side of each arm location respectively, first insulating layer means covering said conductive layerexcept for pockets opposite said arm location, a light emitting diode in each pocket having anode and cathode electrodes having their respective pn junctions in planes perpendicular to said plate, said electrodes being in abutting electrical contact respectively with segment portions on each side of said arm locations, said lead conductors being disposed on the opposite surface of said first insulating layer means from said conductive layer, said first insulating layer means having a window therethrough below each lead conductor opposite a different subterminal respectively, a conductive material filling each of said windows and connecting each of said lead conductors with its associated sub-terminal, and a second insulating layer covering said first insulating layer.

4. An alpha-numeric character display unit according to claim 2, in which said second insulating layer is a transparent resin, and a portion of the resin forming said second layer lies between each diode junction and said transparent nonconductive plate.

5. A combination according to claim 1, in which a transparent resin layer lies between each diode and said transparent glass plate, said resin layer forming a contiguous layer with said conductive layer pattern below each of said diodes.

6. A combination according to claim 1, in which an insulating resin layer is formed on said conductive pattern layer and a second insulating resin layer is formed on said first insulating resin layer, said second insulating layer having grooves therein receiving said conductive leads, and said first insulating layer having windows therethrough below selected points of said conductive leads through which conductive interconnecting leads extend connecting said conductive leads to selected portions of said conductive pattern layer.

7. The combination according to claim 6, in which said first and second insulating layers have pockets therein receiving said diodes.

8. The combination according to claim 1, in which said conductive pattern layer is a composite layer comprising three layers, the first next to said base plate being aluminum, the second covering said aluminum layer being of aluminum-copper alloy, and the third covering said aluminum-copper alloy layer being of copper.

9. The combination according to claim 1, in which each of said display units includes seven diodes in a figure 8 configuration, in which an eighth diode provides a decimal point and in which a ninth diode provides a dash located opposite the center line of the figure eight configuration.

10. The method of making an alpha-numeric character display device which includes coating a transparent glass plate with a conductive layer, mounting said glass plate in spaced relation on a support plate, etching said conductive layer to provide a conductive pattern, said conductive pattern forming separated segments outlining a seven arm figure 8 configuration with said seg ments on opposite sides of the said arms, the segments forming one side of each arm being commonly connected, said etching also includes providing a terminal for each group of commonly connected segments of one side of each arm and separate sub-terminals for the segments forming the other side of each of said arms, coating said conductive pattern with a first insulating resin layer, etching pockets in said first insulating layer for receiving diodes to form the arms of the figure 8 configuration, inserting diodes in said pockets with their pn junction planes perpendicular to said glass plate, covering said first insulating layer with a second insulating layer, forming seven longitudinal grooves in the outer surface of said second insulating layer, providing windows through said first and second insulating layers connecting respectively seven longitudinal grooves with said sub-terminals, and filling said grooves and said windows with a conductive material.

11. The method of mounting electronic parts on an insulating board, which comprises the steps of: forming a conductive lead pattern layer on the insulating board corresponding to the connection terminal of the electronic parts, setting the electronic parts in their desired positions on the insulating board, forming a resin layer having a concavity around each connection point between the conductive lead pattern layer and the connection terminal of the parts, and pouring a conductive resin into the concavity so that the electronic parts and the conductive pattern layer are electrically connected.

12. The method according to claim 11, in which electronic parts are fixed by: pouring a photosensitive adhesive resin between the electronic parts and the insulating board, and exposing the photo-sensitive adhesive resin by using the conductive lead pattern layer so that UNITED STATES PATENT OFFICE CERTIFICATE OF QORRECTLON Patent No. 5,8273% Dated July 50, 197

lnventofls) Setsuo Usul It is certified that error appears in the above-identified patent Letters Patent are hereby corrected as shown below:

line 38,ehange "200!" to --50g.:200cc-.

and that said Coiuinn C u 4311116 57 change "IL -HA' to --IVA'-IVA'--.

Coll-mm line ch ange "39 to "36". Column 6, line 20, Change "14" to 15";

line 22, change "15" to "16";

' line 28 change "16" to "17".

Column line 32 change window 39" to resin layer 36--;

lin 51 change "39" to "365-.

Column 7, line 5 change "68" to Signed and Scaled this twenty-third a Of December 1 9 75 [SEAL] Arrest:

RUTH- C. MfAHSON C. MARSHALL DANN Arresting Officer Commissioner ofPatents and Trademarks

Claims

2. An alpha-numeric character display unit comprising a transparent non-conductive plate, a conductive layer on one surface of said plate shaped in a predetermined pattern, said pattern including separated segment portions spaced to form a seven arm figure 8 configuration with pairs of said segment portions on opposite sides of said arm locations, and separate segment portions forming the other side of the arm locations, the segment portions forming one side of each arm location being commonly connected, a terminal for said commonly connected segment portions, separate sub-terminals for each said other segment portion, separate lead conductors for the segments forming the other side of each arm location respectively, first insulating layer means covering said conductive layer except for pockets opposite said arm locations, a light emitting diode in each pocket having anode and cathode electrodes having their respective pn junctions in planes perpendicular to said plate, said electrodes being in abutting electrical contact respectively with segment portions on each side of said arm locations, a second insulating layer covering said first insulating layer and said diodes, said second insulating Layer having grooves in the upper surface thereof in which said lead conductors are disposed, said insulating layers having windows therethrough below each lead conductor opposite a different sub-terminal respectively, a conductive material filling each of said windows and connecting each of said lead conductors with its associated sub-terminal, and a third insulating layer covering said second insulating layer.

3. An alpha-numeric character display unit, comprising a transparent non-conductive plate, a conductive layer on one surface of said plate shaped in a predetermined pattern, said pattern including separated segment portions spaced to form a seven arm figure 8 configuration with pairs of said segment portions on opposite sides of said arm locations, the separate segment portions forming the other side of the arm locations, the segment portions forming one side of each arm location being commonly connected, a terminal for said commonly connected segment portions, separate sub-terminals for each said segment portion, separate lead conductors for the segments forming the other side of each arm location respectively, first insulating layer means covering said conductive layer except for pockets opposite said arm location, a light emitting diode in each pocket having anode and cathode electrodes having their respective pn junctions in planes perpendicular to said plate, said electrodes being in abutting electrical contact respectively with segment portions on each side of said arm locations, said lead conductors being disposed on the opposite surface of said first insulating layer means from said conductive layer, said first insulating layer means having a window therethrough below each lead conductor opposite a different sub-terminal respectively, a conductive material filling each of said windows and connecting each of said lead conductors with its associated sub-terminal, and a second insulating layer covering said first insulating layer.

10. The method of making an alpha-numeric character display device which includes coating a transparent glass plate with a conductive layer, mounting said glass plate in spaced relation on a support plate, etching said conductive layer to provide a conductive pattern, said cOnductive pattern forming separated segments outlining a seven arm figure 8 configuration with said segments on opposite sides of the said arms, the segments forming one side of each arm being commonly connected, said etching also includes providing a terminal for each group of commonly connected segments of one side of each arm and separate sub-terminals for the segments forming the other side of each of said arms, coating said conductive pattern with a first insulating resin layer, etching pockets in said first insulating layer for receiving diodes to form the arms of the figure 8 configuration, inserting diodes in said pockets with their pn junction planes perpendicular to said glass plate, covering said first insulating layer with a second insulating layer, forming seven longitudinal grooves in the outer surface of said second insulating layer, providing windows through said first and second insulating layers connecting respectively seven longitudinal grooves with said sub-terminals, and filling said grooves and said windows with a conductive material.

12. The method according to claim 11, in which electronic parts are fixed by: pouring a photosensitive adhesive resin between the electronic parts and the insulating board, and exposing the photo-sensitive adhesive resin by using the conductive lead pattern layer so that the parts are fixed thereby.