JP2008235566A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extremely thin display device in which a light emitting diode is arranged on the circuit wiring side of a circuit wiring board and the opposite side of the circuit wiring board is formed as a light unloading face. <P>SOLUTION: The display device 100 comprises: a circuit wiring board 10 comprising a board 10a having a dispersed light diffusion material and a circuit board 10c; a group III nitride based compound semiconductor light-emitting device 201; wire bondings 3n, 3p; and a shading member 4. The group III nitride based compound semiconductor light-emitting device 201 has an insulation board 20, an n type region 21n, and a p type region 22p in this order, and a light emitting region is shown by a bold line A. When light emitted from the light emitting region (bold line) A of the group III nitride based compound semiconductor light-emitting device 201 reaches the board 10a of the circuit wiring board 10, the light is diffused by the light diffusion material dispersed in the board 10a, thereby attaining the same state that an extremely wide region of the board 10a of the circuit wiring board 10 becomes a secondary light emitting source (an arrow of the bold line). Thus, an entire region B not covered with the shading member 4 is recognized as if it emits light. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin display device using 1 to 10 or more light emitting diodes. The present invention is particularly useful as a device for turning on / off the power of various devices or displaying an operation status by switching between lighting and non-lighting. Note that switching between lighting and non-lighting includes switching of the color tone in the display device by lighting one or all of the light emitting diodes having different color tones. It should be noted that the present invention does not exclude a case where the color tone of the display device is arbitrarily adjusted by adjusting the light emission intensity of each light emitting diode having a different color tone.

Gallium nitride blue and green light emitting diodes are provided at a relatively low cost, and the three primary colors of light emitting diodes are aligned with gallium arsenide red light emitting diodes, and there are a variety of full color display matrices and full color display devices. Has been developed. For example, Patent Document 1 discloses a mobile phone display device using a plurality of light emitting diodes in which a light extraction region forms one character (symbol).
JP 2002-51135 A

  In Patent Document 1, a light emitting diode is provided on a circuit wiring board, and a partition wall is provided so that light emission does not leak to other display areas. With such a configuration, a sufficiently thin display device cannot be configured.

  Accordingly, the present inventors have conceived a sufficiently thin display device based on a completely new idea and completed the present invention.

The invention according to claim 1 is a circuit wiring board in which a phosphor or a light diffusing material is dispersed, and a portion excluding a light transmission region that transmits light on the first surface on the light extraction side of the circuit wiring board. And a light emitting diode disposed on the second surface on the other side of the circuit wiring board and connected to the circuit wiring, and a light transmission region on the first surface is desired. The light extraction shape is formed.
According to a second aspect of the present invention, there is provided a circuit wiring board, a light shielding portion formed on a first surface on the light extraction side of the circuit wiring board, excluding a light transmission region that transmits light, and a circuit wiring A light-emitting diode disposed on the second surface on the other side of the substrate and connected to the circuit wiring, and a light transmission region on the first surface forms a desired light extraction shape; The display device further includes a resin in which a phosphor or a light diffusing material is dispersed, which seals the light emitting diode corresponding to at least the light transmission region on the first surface.
According to a third aspect of the present invention, there is provided a circuit wiring board, a light shielding portion formed on a first surface on the light extraction side of the circuit wiring board, except for a light transmission region that transmits light, And a light emitting diode disposed on the second surface on the other side of the circuit wiring board and connected to the circuit wiring, which is formed at least in a light transmission region on the surface of the circuit board and containing a phosphor or a light diffusing material. And a light transmission region on the first surface forms a desired light extraction shape.

  In the invention according to each claim of the present application, the circuit wiring board needs not to be light-shielding, but when the phosphor or the light diffusing material is dispersed, it is not necessarily required to be highly transmissive to light. No. Furthermore, in any of the claimed inventions, the film has an arbitrary translucency (transmittance with respect to the wavelength of light) such as a so-called smoked or colored one for visual effect. Good as a thing. For example, a transparent material may be used as the circuit wiring formed on the circuit wiring board, but a metal film made of an opaque material may be used. A method of connecting the configuration of the light emitting diode and the circuit wiring of the circuit wiring board is arbitrary. The sealing resin in the case of using the sealing resin is not necessarily required to be highly transmissive to light. For example, a phosphor is a substance that converts the light emission wavelength of a light emitting diode. It is assumed that the light of the light emission wavelength of the light emitting diode itself and the light of the light emission wavelength converted by the phosphor are combined and can be visually recognized in other colors. To do. The light diffusing material does not extract light from the light emitting diode only in the linear direction, but allows the entire light transmission region to be visually recognized as emitting light from any direction. In addition, the light-shielding part includes both a light reflecting material and a light absorbing material. For example, when using a light reflecting material, it is preferable to provide a light absorbing material on the viewing side from the viewpoint of vision. .

The circuit wiring board in which the phosphor or the light diffusing material is dispersed is not limited to the one in which the phosphor or the light diffusing material is uniformly dispersed in the thickness direction of the circuit wiring board. In which phosphors or light diffusion materials are dispersed in a concentrated manner.
Further, in claim 2, corresponding to the region where the light shielding portion is not provided, the region where the light shielding portion is not provided is a light transmission region, and the entire region can be visually recognized as emitting light from any direction. It is for doing so. For this purpose, a sealing resin in which a phosphor or a light diffusing material is dispersed is provided on the opposite side of the area where the light shielding portion is not provided and the circuit wiring board.
In addition, in claim 3, a layer containing a phosphor or a light diffusing material is formed at least in a portion where no light-shielding portion is provided. This excludes those in which the layer is formed in a portion provided with a light-shielding portion. In addition, the vertical relationship among the light shielding portion, the layer, and the circuit wiring board is not limited. For example, the order may be the circuit wiring board, the layer, and the light shielding part, or the layer, the circuit wiring board, and the light shielding part.

The invention according to claim 4 is characterized by having a reflective film provided so as to cover the light emitting diode of the circuit wiring board corresponding to at least the region where the light shielding portion is not provided. The reflective film does not exclude being directly formed on the light emitting diode, but includes a film that indirectly covers the light emitting diode through another insulating material.
The invention according to claim 5 is characterized in that the light shielding portion is formed of a light shielding material formed on the transparent thin film. The invention according to claim 6 is characterized in that the light shielding portion is formed of a light shielding material formed on the surface of the circuit wiring board on the light extraction side.
The difference between claim 5 and claim 6 is, for example, whether the thin film transparent sheet on which the light shielding part is formed is traced on the circuit wiring board or whether the light shielding part is formed on the circuit wiring board itself.

  If a light emitting diode is disposed on the circuit wiring side of the circuit wiring board and the opposite side of the circuit wiring board is a light extraction surface, an extremely thin display device is obtained by adding the thickness of the light emitting diode and the thickness of the circuit wiring board. Can be formed. However, although the thickness of the display device is slightly increased by wire bonding the light emitting diode or by forming a sealing resin, the display device is still extremely thin.

Even if a light emitting diode is disposed on one surface of a transparent circuit wiring board, the light emitting diode itself is only visually recognized. Therefore, any means for dispersing the light diffusing material in the circuit wiring board, providing the circuit wiring board with a layer containing the light diffusing material on either side, and dispersing the light diffusing material in the resin for sealing the light emitting diode. If it takes, it can be made to visually recognize so that the whole light extraction shape may light-emit.
Further, when a phosphor is used instead of or in addition to the light diffusing material, the entire light extraction shape can be emitted in a color tone different from the color of the light emitting diode single color. (Effects of claims 1 to 3)

  When a reflective film is provided so as to cover the light emitting diode, light leaking to the side opposite to the light extraction side can be guided to the light extraction side, and light emitted from the light emitting diode can be effectively used.

The light-emitting diode used in the present invention is monochromatic, full-color, or other arbitrary. Further, the number of light emitting diodes used in one region forming one symbol is also arbitrary. As the light emitting diode, a light emitting diode which emits light having a necessary color tone can be arbitrarily selected. For example, a purple or green light emitting diode using a group III nitride compound semiconductor (Al _x Ga _y In _1-xy N) may be selected. When combined with a phosphor, a light emitting diode having an emission wavelength in the near ultraviolet to blue region and a yellow phosphor may be combined to form a white diode, or a phosphor of a desired color and an ultraviolet light emitting diode may be combined.

The electrode structure of the light emitting diode is also arbitrary, and the connection method with the circuit wiring of the circuit wiring board can be arbitrarily selected. For example, when using a group III nitride compound semiconductor (Al _x Ga _y In _1-xy N) light emitting element, a reflective film is formed on the back surface of the chip substrate with a so-called face-up type structure (light extraction on the p-type semiconductor layer side). You may do it. In this case, the connection to the circuit wiring board may be a solder bump. Alternatively, a so-called flip chip type structure (light extraction on the insulating substrate side) having a reflective film on the p-type semiconductor layer side may be wire-bonded. When performing wire bonding, wedge bonding using ultrasonic waves eliminates the need for heat treatment and reduces the adverse effects on other components. Details of these will be described later.

  The material of the circuit wiring board is completely arbitrary except that a light-shielding base material is inappropriate. The base material is preferably a light-transmitting resin or inorganic material. When the wiring material corresponding to the light transmission region is made of indium tin oxide (ITO), the shadow of the wiring does not occur during display. As the light diffusing material, spherical or other fine particles are available, and in addition to being dispersed in the base material of the circuit wiring board, a thin film coated and fixed with the light diffusing material may be used. The same applies to the case of using a phosphor or an organic dye.

  The material for forming the light-shielding portion is basically preferably a light absorbing material, but may have a double structure with a light absorbing material having the circuit wiring board side as a light reflecting material. The light shielding portion can be formed by screen printing, vapor deposition, or other methods corresponding to the material to be used. A film with a light shielding material may be attached. The sealing resin is completely arbitrary with respect to the base material resin and other additives, and can be arbitrarily selected when a light diffusing material, a phosphor, an organic dye or the like is contained. In the present invention, replacing the sealing resin with an inorganic material is not excluded.

  As the reflective film formed so as to cover the light emitting diode, any metal or the like can be used. However, in order to maintain insulation from the circuit wiring of the circuit wiring board, a device such as an insulating material is required. .

  FIG. 1 is a cross-sectional view showing a main part of a display device 100 according to a specific first embodiment of the present invention. The display device 100 includes a circuit wiring board 10 composed of a substrate portion 10a in which a light diffusion material is dispersed and circuit wiring 10c, a group III nitride compound semiconductor light emitting element 201, wire bondings 3n and 3p, and a light shielding member 4. . The group III nitride compound semiconductor light emitting device 201 includes an insulating substrate 20, an n-type group III nitride compound semiconductor region 21n, and a p-type group III nitride compound semiconductor region 22p in this order. In FIG. 1, the light emitting region is indicated by a thick line A sandwiched between an n-type group III nitride compound semiconductor region 21n and a p-type group III nitride compound semiconductor region 22p. The region A can be a light emitting layer having a single layer, a single quantum well structure, or a multiple quantum well structure in addition to the pn interface, and is simply illustrated. Although not shown in FIG. 1, an n-electrode is provided between the n-type group III nitride compound semiconductor region 21n and the wire bonding 3n, and between the p-type group III nitride compound semiconductor region 22p and the wire bonding 3p. Suppose that a p-electrode is formed. In FIG. 1, the circuit wiring 10 c is described as if it covers most of the area where the group III nitride compound semiconductor light emitting element 201 is not disposed on the lower side of the substrate portion 10 a in FIG. 1. 10c may be formed so as to be able to energize the group III nitride compound semiconductor light emitting device 201, and does not need to cover the lower side of the substrate portion 10a.

  In the display device 100 of FIG. 1, when the light emitted from the light emitting region (thick line) A of the group III nitride compound semiconductor light emitting element 201 reaches the substrate portion 10a of the circuit wiring substrate 10, Light is diffused by the dispersed light diffusing material. As a result, the extremely large area of the substrate portion 10a of the circuit wiring board 10 becomes the same state as the secondary light emitting source. This is indicated by a thick arrow in FIG. That is, the light from the light emitting region (thick line) A diffuses in various directions within the substrate portion 10a. Thus, finally, the entire light transmission region B that is not covered with the light shielding member 4 is visually recognized as if it is emitting light. As described above, the display device 100 in FIG. 1 emits light from the group III nitride compound semiconductor light emitting element 201 as a point light source from the entire light transmission region B by the substrate portion 10a in which the light diffusion material is dispersed. It can be visually recognized. Therefore, by forming the light shielding member 4 in a desired shape, it is possible to provide a display device for the light transmission region B that is shaped into a desired shape.

  FIG. 2 is a cross-sectional view showing a main part of a display device 200 according to a second specific example of the present invention. In the display device 200, the circuit wiring board 10 including the substrate portion 10a and the circuit wiring 10c in which the light diffusion material is dispersed is the same as the display device 100 in FIG. On the other hand, in the display device 200 of FIG. 2, the group III nitride compound semiconductor light emitting element 202 is connected to the circuit wiring 10c like a flip chip. That is, the group III nitride compound semiconductor light emitting device 202 used in the display device 200 of FIG. 2 is basically the same as the group III nitride compound semiconductor light emitting device 201 of FIG. A type III-nitride compound semiconductor region 21n and a p-type group III nitride compound semiconductor region 22p in this order, an n-type group III nitride compound semiconductor region 21n, and a p-type group III nitride system A light emitting region (bold line) A is sandwiched between the compound semiconductor regions 22p. The p-type group III nitride compound semiconductor region 22p is connected to the circuit wiring 10c via a p electrode (not shown), and the n-type group III nitride compound semiconductor region 21n is a circuit via an n electrode (not shown) and bumps 3b. It is connected to the wiring 10c. Note that a p-electrode (not shown) is a translucent thin film electrode.

  In the display device 200 of FIG. 2, similarly to the display device 100 of FIG. 1, light from the light emitting region (thick line) A diffuses in various directions within the substrate portion 10a. The entire light transmission region B that is not covered with is visually recognized as if light is emitted. Therefore, by forming the light shielding member 4 in a desired shape, it is possible to obtain a display device for the light transmission region B shaped into a desired shape.

[Modified Example of Substrate 10a]
When a phosphor is used instead of the light diffusion material dispersed in the substrate portion 10a of FIG. 1, light having a wavelength different from the emission wavelength of the group III nitride compound semiconductor light emitting element 201 may be emitted from the phosphor. It becomes possible. For example, if the emission wavelength of the group III nitride compound semiconductor light-emitting element 201 is in the blue region and a phosphor that absorbs the emission wavelength and emits yellow fluorescence is used, white light emission can be obtained from the light transmission region B. It is. Alternatively, if the emission wavelength of the group III nitride compound semiconductor light-emitting element 201 is in the ultraviolet region and a phosphor that absorbs the emission wavelength and emits fluorescence of any color is used, light emission of any color can be obtained from the light transmission region B. Is also possible. At this time, if phosphors having different fluorescent colors are mixed, the color tone can be adjusted more easily. Further, if a colored plate is used as the substrate portion 10a in FIG. 1, the color tone of the light emitting element can be changed. The same applies to the substrate portion 10a in FIG.

[When a reflective film is formed on the light emitting element]
In the group III nitride compound semiconductor light emitting device 201 of FIG. 1, the p electrode and the n electrode (not shown) are highly reflective electrodes, so that the group III nitride compound semiconductor light emitting device 202 of FIG. By forming a highly reflective film on the back surface (lower surface in FIG. 2) of the insulating substrate 20, light leaking downward from the light emitting region A in each diagram in the substrate portion of the circuit wiring substrate 10. It can be reflected to the 10a side. The reflective film may be formed as a case or a cover as in the following embodiment.

  Further, it is optional to encapsulate the group III nitride compound semiconductor light emitting device 201 of FIG. 1 or the group III nitride compound semiconductor light emitting device 202 of FIG. 2 or to cover the circuit wiring 10c with an insulating material. .

  FIG. 3 is a cross-sectional view showing a main part of a display device 300 according to a specific third embodiment of the present invention. The display device 300 includes a circuit wiring board 103 composed of a substrate portion 10b made of a transparent material and circuit wiring 10c, a group III nitride compound semiconductor light emitting element 201, wire bondings 3n and 3p, a light shielding member 4, and a light diffusing material. It comprises a sealing resin 5 and a frame portion 6 made of a highly reflective metal. In the display device 300 of FIG. 3, the light diffusing material is mixed with the sealing resin 5 and is not included in the substrate portion 10b of the circuit wiring board 103, except that the circuit wiring 10c and the group III nitride compound semiconductor light emitting element 201 are used. The basic structures of the wire bondings 3n and 3p and the light shielding member 4 are the same as those of the display device 100 of FIG.

  In the display device 300 of FIG. 3, when light emitted from the light emitting region (thick line) A of the group III nitride compound semiconductor light emitting element 201 reaches the substrate portion 10 b of the circuit wiring substrate 103, Transmits upward. On the other hand, when the light emitted from the light emitting region (thick line) A reaches the light diffusion material mixed in the sealing resin 5 after being reflected directly or by the frame portion 6 made of a highly reflective metal, the light diffusion Depending on the material, light will diffuse. As a result, the extremely large area under the circuit wiring board 103 becomes the same state as the secondary light emitting source. This is indicated by thick arrows in FIG. That is, the light from the light emitting region (thick line) A diffuses in various directions within the sealing resin 5. Thus, finally, the entire light transmission region B that is not covered with the light shielding member 4 is visually recognized as if it is emitting light. As described above, the display device 300 of FIG. 3 emits light from the group III nitride compound semiconductor light emitting element 201 as a point light source from the entire light transmission region B by the sealing resin 5 in which the light diffusion material is dispersed. It can be visually recognized as light emission. Therefore, by forming the light shielding member 4 in a desired shape, it is possible to provide a display device for the light transmission region B that is shaped into a desired shape.

[Modification of Example 3]
Instead of the group III nitride compound semiconductor light emitting element 201 of the display device 300 of FIG. 3, the connection may be made in the same manner as the group III nitride compound semiconductor light emitting element 202 of the display device 200 of FIG. Further, instead of the substrate portion 10b made of the transparent material of the display device 300 in FIG. 3, the substrate portion 10a in which the light diffusion material is dispersed in the display device 100 in FIG. 1 may be used. In this case, as a result of the light being diffused at two locations of the sealing resin 5 in which the light diffusion material is dispersed and the substrate portion 10a in which the light diffusion material is dispersed, the entire light transmission region B emits light more uniformly. As seen.

[Other variations]
For example, FIG. As in A, the light shielding member 4 is not directly provided on the substrate portion 10a or 10b, but is provided on a thin film (film) 41 made of a transparent material, for example, by printing or the like, and then the light shielding member 4 is shielded on the substrate portion 10a or 10b. A thin film (film) 41 made of a transparent material provided with the member 4 may be bonded.

  In addition, FIG. As in B, a circuit wiring board having a light diffusing material on the surface may be formed by bonding a thin film (film) 104 having a light diffusing material to the substrate portion 10b made of a transparent material. At this time, the side to which the thin film (film) 104 having the light diffusing material is bonded is shown in FIG. It may be the light extraction side on which the light shielding member 4 is formed as in B, or conversely the side on which the circuit wiring 10c is formed. In either case, the light shielding member 4 or the circuit wiring 10c may be formed after the thin film (film) 104 having a light diffusing material is bonded to the substrate portion 10b made of a transparent material. After forming 10c, a thin film (film) 104 having a light diffusing material may be adhered. Treatment such as drilling for conduction is arbitrarily performed.

  The present invention is not limited to the above embodiments. On the basis of the configuration described in the embodiment, it can be appropriately changed using any available member. For example, the light-emitting element is not limited to a group III nitride compound semiconductor light-emitting element, and red to yellow-green GaAs-based or InP-based light-emitting elements may be used. When an element using a conductive chip substrate is connected to circuit wiring, the substrate may be directly connected to circuit wiring. In the present invention, it is only necessary to visually recognize as if the light transmission region B composed of the region where the light shielding member is not formed is finally shining, and the circuit wiring, the light emitting element, and the wire, solder, bump, etc. for conducting them. It is not always necessary to use a translucent material. The light diffusing material may be dispersed in both the substrate portion of the circuit wiring board and the sealing resin, and a thin film (light diffusing sheet) having the light diffusing material may be stacked on the light extraction side. Naturally, the combined use of the light diffusing material and the phosphor is included in the present invention.

In addition, the fixing method to the circuit wiring board of a light emitting element is arbitrary. The description of the substrate having an insulating substrate is omitted in the figure, but an adhesive may be used.
Moreover, although the case where the frame part which consists of a highly reflective metal was formed in FIG. 3, you may dip in the paste etc. which contain the highly reflective member, for example, and may form a film.

  The present invention can be used for arbitrary display applications by displaying symbols in units of light emitting areas or displaying numerical values or the like by a two-dimensional arrangement of light emitting areas, such as a display device on a front panel of a vehicle, It can be used for digital display clocks and display parts of home appliances. Moreover, it can be set as the operation part of the push-down switch which has a function which displays an ON / OFF state by lighting / non-lighting.

Sectional drawing which shows the principal part of the display apparatus 100 which concerns on the specific 1st Example of this invention. Sectional drawing which shows the principal part of the display apparatus 200 which concerns on the specific 2nd Example of this invention. Sectional drawing which shows the principal part of the display apparatus 300 which concerns on the specific 3rd Example of this invention. Sectional drawing which shows a modification. Sectional drawing which shows another modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 103: Circuit wiring board 10a: The board | substrate part in which the light-diffusion material was disperse | distributed 10b: The board | substrate part which consists of a transparent material 10c: Circuit wiring 104: The thin film (film) which has a light-diffusion material
201: Group III nitride compound semiconductor light emitting device 4: Light shielding member 41: Thin film (film) made of transparent material
5: Sealing resin in which a light diffusing material is dispersed 6: Frame portion made of highly reflective metal A: Light emitting region of group III nitride compound semiconductor light emitting device 201 B: Region made of no light shielding member 4 formed Light transmission area

Claims (6)

A circuit wiring board in which phosphors or light diffusion materials are dispersed;
A light-shielding portion formed on the first surface on the light extraction side of the circuit wiring board on a portion excluding a light transmission region that transmits light;
A light emitting diode disposed on the second surface on the other side of the circuit wiring board and connected to the circuit wiring;
The display device, wherein the light transmission region on the first surface forms a desired light extraction shape. A circuit wiring board;
A light-shielding portion formed on the first surface on the light extraction side of the circuit wiring board on a portion excluding a light transmission region that transmits light;
A light emitting diode disposed on the second surface on the other side of the circuit wiring board and connected to the circuit wiring;
The light transmission region on the first surface forms a desired light extraction shape;
A display device further comprising: a resin in which a phosphor or a light diffusing material is dispersed, which seals the light emitting diode, corresponding to at least the light transmission region on the first surface. A circuit wiring board;
A light-shielding portion formed on the first surface on the light extraction side of the circuit wiring board on a portion excluding a light transmission region that transmits light;
A layer containing a phosphor or a light diffusing material, at least formed in the light transmission region on the first surface;
A light emitting diode disposed on the second surface on the other side of the circuit wiring board and connected to the circuit wiring;
The display device, wherein the light transmission region on the first surface forms a desired light extraction shape. 4. The reflective film according to claim 1, further comprising a reflective film provided so as to cover the light emitting diode of the circuit wiring board corresponding to at least a region where the light shielding portion is not provided. The display device described. The display device according to claim 1, wherein the light shielding portion is formed of a light shielding material formed on a transparent thin film. 5. The display device according to claim 1, wherein the light shielding portion is formed of a light shielding material formed on a light extraction side surface of the circuit wiring board. .

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