JP2006148051A - Light emitting device, backlight unit for illumination and display device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the luminous efficiency and color rendering properties of a light emitting device having two or more kinds of luminescent substances that absorb light and emit light. <P>SOLUTION: A light emitting device is provided with: a first light emitting part 4 containing a luminescent material excited by a light source 3 and light emitted by the light source 3 and emitting light containing a component with a wavelength longer than that of the light emitted by the light source 3; and a second light emitting part 5 containing the luminescent material excited by the light source 3 and the light emitted by the first light emitting part 4 and emitting light containing the component with the wavelength longer than that of the light emitted by the first light emitting part 4. The light emitting device is provided with a light blocking part 6 preventing the incidence of at least a part of the light emitted by the first light emitting part 4 to the second light emitting part 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device, illumination, a backlight unit for a display device, and a display device.

  Conventionally, a cold cathode tube or the like has been used as a light source such as an illumination or a backlight for a liquid crystal display. In recent years, however, a pseudo-white light source has been developed as a light source that replaces this by combining a light source that emits blue light and a substance that absorbs blue light and emits yellow light. In this pseudo white light source, for example, an InGaN light emitting diode is used as a light source that emits blue light, and yttrium aluminate to which cerium is added is used as a substance that emits yellow light.

  However, the spectrum of light emitted from the pseudo white light source is essentially lacking in the green light component and the red light component. For this reason, the pseudo white light source has low color rendering properties and low color reproducibility. In order to solve this, the yttrium aluminate component is adjusted to emit yellow-green light, and in addition to this, a substance that absorbs blue light and emits red light is added to yttrium aluminate. Thus, it has been proposed to compensate for the shortage of the red component of the light emitted by the pseudo-white light source and to improve color rendering and color reproducibility.

  However, a substance that emits red light absorbs not only blue light but also light that has a longer wavelength than blue light but a shorter wavelength than red light, that is, light such as green and yellow. There are many. Examples of such materials include: alkaline earth metal sulfides activated with europium, alkaline earth metals and silicon nitrides activated with europium, alkaline earth metals and silicon oxynitrides activated with europium Etc. These substances usually absorb light with a wavelength of 400 nm to 580 nm well and emit orange to red light having a peak at 580 nm to 680 nm.

  Substances that emit orange to red light as typified above absorb green to yellow light having a shorter wavelength, and thus emit substances that emit orange to red light and green to yellow light. When mixed with a substance, a part of the light emitted by the substance emitting green to yellow light is absorbed by the substance emitting orange to red light, and the luminous flux of the light emitting device is significantly reduced.

  At present, attempts have been made to solve this decrease in luminous flux due to absorption of short-wavelength light by a luminescent material that emits long-wavelength light. For example, in Patent Document 1, in a light emitting device including two kinds of substances (referred to as substance A and substance B) that absorb light from a light source and emit light of different wavelengths, substance A (here, orange to When the substance B (corresponding to a substance that emits red light) absorbs part of the light emitted by the substance B (which corresponds to a substance that emits green to yellow light here), the substance A is arranged closer to the light source side than the substance B. By doing so, it is said that the color rendering properties can be improved and the reduction of the luminous flux can be prevented.

Further, conventionally, a display device has been used in which an image forming unit on which an image is formed is irradiated with light (backlight) from the back to clearly display the image of the image forming unit. Examples of such display devices include a liquid crystal display using a liquid crystal unit as an image forming unit, an internal lighting sign (an emergency exit display lamp, a road sign, etc.) that illuminates a sign (image forming unit) with internal illumination, etc. Is mentioned.
These display devices usually have a backlight unit for irradiating light from the back to the image forming unit. Conventionally, fluorescent lamps, cold cathode tubes, and the like have been used as such backlight units.

However, when a fluorescent lamp or a cold cathode tube is used as the backlight unit, there are problems such as difficulty in miniaturization of the backlight unit and short service life.
Further, since these use mercury, there is a concern about the influence on the environment, and there is a possibility that the handling becomes complicated.

Therefore, in recent years, as described above, it has been proposed to use a light emitting device using a light source and a fluorescent material that emits fluorescence by absorbing light from the light source as a backlight unit. For example, a technique has been proposed in which a pseudo white light source using the InGaN-based light emitting diode as described above and yttrium aluminate to which cerium is added as a light source and a light emitting material is used as a backlight unit.
In addition, for example, it is also proposed to use the light emitting device proposed in Patent Document 1 as a backlight.

JP 2004-71726 A

However, in the technique of Patent Document 1, since the light emitted from the substance A and the substance B is emitted in all directions, most (approximately half) of the light emitted from the substance B is absorbed by the substance A and is notable. A decrease in luminous flux is inevitable. For this reason, the luminous efficiency of the light emitting device was low.
In addition, as described above, a light emitting device such as a pseudo white light source having a light source that emits blue light and a substance that absorbs blue light and emits yellow light has high luminous efficiency but has insufficient color rendering properties.

  Further, in a display device using a conventional light emitting device, white light used for a backlight is used to display the color of an image formed on the image forming unit with high reproducibility (that is, to improve color reproducibility). Is preferably light including the three primary colors of light. Here, the three primary colors of light are red, blue and green. According to this viewpoint, a conventional light emitting device using a light source that emits blue light and a fluorescent material that emits yellow light has insufficient red and green light, and thus color reproducibility is not sufficient.

  Further, when the technique described in Patent Document 1 is used for the display device, white light including all of blue, green, and red can be emitted, so that there is no problem in color reproducibility. However, as described above, light emitted from the fluorescent material (that is, red and green light) is emitted in all directions, and most of the light emitted from the green fluorescent material is absorbed by the red fluorescent material, resulting in a significant luminous flux. A decrease occurs. For this reason, the luminous efficiency of the backlight unit is lowered, and the energy consumed by the display device using the backlight unit is likely to be increased.

  The present invention was devised in view of the above problems, and improves the light emission efficiency and color rendering of a light-emitting device having two or more light-emitting substances that absorb light and emit light, and uses the light-emitting device. It is an object of the present invention to provide a backlight unit for a display device and a display device, and to provide a display device with excellent color reproducibility using a backlight unit having high luminous efficiency.

  The inventors of the present invention have made extensive studies to solve the above problems, and as a result, in a light-emitting device using two or more kinds of light-emitting substances, light emitted from one light-emitting substance is incident on a region containing the other light-emitting substance. The knowledge that the amount of light emitted from one light-emitting substance is absorbed by the other light-emitting substance can be suppressed, and as a result, the light emission efficiency and color rendering of the light-emitting device can be improved. Obtained.

  Based on the above knowledge, in a display device using a backlight, a backlight unit that emits white light has a blue light source that emits blue light and a green light emitter that emits light when excited by the blue light. A green light emitting unit that emits green light, and a red light emitting unit that emits red light having a red light emitting body that emits light when excited by blue light, and includes the green light emitting unit and the red light emitting unit. It was found that by forming each of them at least partially independently, the luminous efficiency of white light can be improved and the color reproducibility of the display device can be improved, and the present invention has been completed.

  That is, the light-emitting device of the present invention includes a first light emission including a light source and at least one light-emitting substance that can emit light including a component having a longer wavelength than the light emitted from the light source when excited by the light emitted from the light source. And a second light emission containing at least one light emitting material that can be excited by the light emitted from the light source and the first light emitting part and emit light including a component having a longer wavelength than the light emitted from the first light emitting part And a light shielding part for preventing at least a part of the light emitted from the first light emitting part from entering the second light emitting part (Claim 1). Thereby, it is possible to suppress the light emitted from the first light emitting unit from being absorbed by the second light emitting unit, and as a result, it is possible to improve both the light emission efficiency and the color rendering of the light emitting device.

At this time, it is preferable that the light shielding part reflects at least a part of the light emitted from the first light emitting part (claim 2). Thereby, the light emitted from the first light emitting unit can be used effectively, and the light emission efficiency and color rendering of the light emitting device can be further improved.
The illumination of the present invention is characterized by using the above light-emitting device (claim 3).
Furthermore, the backlight unit for a display device of the present invention uses the above light emitting device (claim 4).
Further, the display device of the present invention uses the above light emitting device (claim 5).

  Furthermore, another display device of the present invention includes a backlight unit that emits a backlight, and an image forming unit that irradiates the backlight emitted from the backlight unit on the back side and forms an image on the surface side. A display device comprising: a light source; and at least one luminescent material capable of emitting light including a light source and a component having a longer wavelength than the light emitted from the light source when excited by the light emitted from the light source A first light-emitting part containing the light-emitting element and at least partly independent of the first light-emitting part, and longer than the light emitted from the first light-emitting part when excited by the light emitted from the light source and the first light-emitting part And a second light-emitting portion containing at least one light-emitting substance capable of emitting light including a wavelength component (Claim 6). Thereby, both the luminous efficiency and color reproducibility of the display device can be improved.

  Further, another display device of the present invention includes a backlight unit that emits white light, and an image forming unit that irradiates the white light emitted from the backlight unit on the back side and forms an image on the surface side. The backlight unit includes a blue light source that emits blue light, a green light emitter that emits light when excited by the blue light, and emits green light. And a red light-emitting portion that is formed at least partially independently of the green light-emitting portion, has a red light-emitting body that emits light when excited by the blue light, and emits red light. This also improves both the luminous efficiency and color reproducibility of the display device.

In this case, the display device preferably includes a diffusion plate that diffuses light emitted from the backlight unit between the backlight unit and the image forming unit.
In addition, the display device preferably includes a light guide plate that guides light from the backlight unit to the image forming unit.

According to the present invention, it is possible to obtain a light emitting device excellent in both luminous efficiency and color rendering.
Moreover, if the light-emitting device of this invention is used, the illumination excellent in luminous efficiency and color rendering property, the backlight unit for display apparatuses, and a display apparatus can be obtained.
Further, according to the display device of the present invention, it is possible to improve both the light emission efficiency and the color reproducibility of the display device.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following exemplifications and the like, and can be arbitrarily modified without departing from the gist of the present invention.

[I. Description of light emitting device]
[I-1. Overview of Light Emitting Device]
The light-emitting device of the present invention includes a light source, a first light-emitting unit, a second light-emitting unit, and a light-shielding unit, and emits light toward a direction in which light is to be emitted (hereinafter referred to as “predetermined direction” as appropriate). Is configured to release. Further, the light emitting device usually includes a frame as a base for holding the light source, the first light emitting unit, the second light emitting unit, and the light shielding unit.

[I-1-1. flame]
The frame is a base that holds the light source, the first light emitting unit, the second light emitting unit, and the light shielding unit, and its shape, material, and the like are arbitrary.
As specific examples of the shape of the frame, a plate shape, a cup shape, or the like can be used according to the application. Further, among the illustrated shapes, a cup-shaped frame is preferable because it can have directivity in the light emission direction and can effectively use light emitted from the light-emitting device.

As specific examples of the material of the frame, an appropriate material such as an inorganic material such as a metal, an alloy, glass, carbon, or ceramics, or an organic material such as a synthetic resin can be used.
Furthermore, it is preferable to use a material with good heat dissipation as the material of the frame. For example, it is preferable to use a material having high thermal conductivity. Normally, the light source generates heat during use. However, if the frame is made of a material having good heat dissipation, it can be used stably even if heat is generated during use.
Furthermore, it is preferable to use an insulating material for the frame.

  However, the surface of the frame on which the light emitted from the light source, the first light emitting unit, and the second light emitting unit hits is preferably enhanced in the reflectance of at least one of the components of the hit light, In particular, it is more preferable that the reflectance of light in the entire visible light range is increased. Therefore, it is preferable that at least the surface that is exposed to light is formed of a material having high reflectance. Specific examples include forming the entire frame or the surface of the frame with a material (such as injection molding resin) containing a material having a high reflectance such as glass fiber, alumina powder, titania powder and the like.

  The specific method for increasing the reflectivity of the frame surface is arbitrary. In addition to selecting the material of the frame itself as described above, for example, plating with a metal or alloy having a high reflectivity such as silver, platinum, or aluminum. Alternatively, the reflectance of light can be increased by vapor deposition.

In addition, the part which raises a reflectance may be the whole frame, or a part, but normally, the whole surface of the part which the light emitted from a light source, a 1st light emission part, and a 2nd light emission part hits is sufficient. It is desirable that the reflectivity be increased.
In addition, the frame is usually provided with electrodes for supplying power to the light source.

[I-1-2. light source]
The light source emits excitation light of a luminescent material contained in the first light emitting unit and the second light emitting unit, and also emits one component of light emitted from the light emitting device. That is, a part of the light emitted from the light source is absorbed as excitation light by the luminescent material in the first light emitting part and the second light emitting part, and another part is emitted from the light emitting device in a predetermined direction. It has become so.

  The type of the light source is arbitrary, and an appropriate one can be selected according to the use and configuration of the light emitting device. Examples of the light source include a light-emitting diode (hereinafter referred to as “LED” as appropriate), an edge-emitting or surface-emitting laser diode, an electroluminescence element, and the like, but an inexpensive LED is usually preferable.

  The light emission wavelength of the light emitted from the light source is also arbitrary, and a light source that emits light having an appropriate light emission wavelength may be used according to the light emitted from the light emitting device. For example, when white light is emitted from the light emitting device, the emission wavelength of the light emitted from the light source is usually 370 nm or more, preferably 380 nm or more, and usually 500 nm or less, preferably 480 nm or less.

Specific examples of the light source include an LED using an InGaN-based, GaAlN-based, InGaAlN-based, ZnSeS-based semiconductor, or the like that has been crystal-grown on a substrate such as silicon carbide, sapphire, or gallium nitride by a method such as MOCVD. .
One light source may be used alone, or two or more light sources may be used in combination. Furthermore, only one type of light source may be used, or two or more types of light sources may be used in combination. In particular, in order to improve the color rendering properties of the light emitting device, it is preferable to provide a light source in each of the first light emitting unit and the second light emitting unit.

  Further, in the case where a light source is not provided for each of the first light emitting unit and the second light emitting unit, and a common light source is provided for the first light emitting unit and the second light emitting unit, the first light emitting unit is the second light emitting unit. It is preferable to be closer to the light source. That is, it is preferable that the distance between the portions where the light source and the first light emitting portion are closest to each other is smaller than the shortest distance between the portions where the light source and the second light emitting portion are closest.

  For example, when the light blocking unit is configured to block only part of the light between the first light emitting unit and the second light emitting unit, the light source is provided at a position closer to the second light emitting unit than the first light emitting unit. It is assumed that the light from the light source first enters the second light emitting unit. At this time, the second light emitting unit emits light using the light from the light source as excitation light. However, since the light from the second light emitting unit cannot be used as excitation light by the first light emitting unit, the first light emitting unit should emit light. The light intensity emitted from the light-emitting device may vary from the target value due to insufficient light intensity or the light emitted from the second light-emitting portion may become too strong, and color rendering may be reduced. On the other hand, when the first light emitting unit is provided at a position closer to the light source than the second light emitting unit, the light emitted from the light source first enters the first light emitting unit. As a result, the first light emitting unit emits light using the light from the light source as excitation light, so that the first and second light emitting units emit light smoothly. Therefore, variation in the color of light emitted from the light emitting device is reduced, and color rendering can be further improved.

  Even when the first light emitting unit is disposed closer to the light source than the second light emitting unit, the intensity of the light emitted from the light source and incident on each of the first light emitting unit and the second light emitting unit is This is also related to the area of the surface where each of the first light emitting unit and the second light emitting unit receives light. Therefore, the distance from the light source to each of the first light emitting unit and the second light emitting unit, and the area of each light receiving surface are determined by the intensity of light received by the first light emitting unit from the intensity of light received by the second light emitting unit. Is preferably set to be large.

  Moreover, when attaching a light source to a flame | frame, the specific method is arbitrary, For example, it can attach using solder. The type of solder is arbitrary, but, for example, AuSn, AgSn, or the like can be used. Moreover, when using solder, it is also possible to supply electric power from the electrodes formed on the frame through the solder. In particular, when a large current type LED or laser diode in which heat dissipation is important is used as a light source, it is effective to use solder for installation of the light source because the solder exhibits excellent heat dissipation.

  Moreover, when attaching a light source to a flame | frame by means other than solder | pewter, you may use adhesive agents, such as an epoxy resin, an imide resin, an acrylic resin, for example. In this case, by using a paste in which conductive fillers such as silver particles and carbon particles are mixed with the adhesive, the adhesive can be energized to supply power to the light source as in the case of using solder. It is also possible to make it. Furthermore, it is preferable to mix these conductive fillers because heat dissipation is improved.

Furthermore, the method for supplying power to the light source is arbitrary. In addition to energizing the solder and adhesive described above, the light source and the electrode may be connected by wire bonding to supply power. There is no restriction | limiting in the wire used at this time, A raw material, a dimension, etc. are arbitrary. For example, a metal such as gold or aluminum can be used as the material of the wire, and the thickness can be usually 20 μm to 40 μm, but the wire is not limited to this.
Another example of a method for supplying power to the light source is a method for supplying power to the light source by flip chip mounting using bumps.

[I-1-3. First light emitting unit and second light emitting unit]
The first light emitting unit is formed to include at least one light emitting substance that is excited by light emitted from the light source and emits light including a component having a longer wavelength than the light emitted from the light source. There is no restriction | limiting in particular in the shape of this 1st light emission part, Moreover, it can provide independently in one place, and can also be divided and provided in two or more places. The luminescent material used for the first light emitting unit will be described in detail later.

  In the first light emitting unit, light emitted from the light source is received, and thereby the luminescent material emits light using the received light as excitation light. The emitted light is emitted outside the light emitting device as a component of light emitted by the light emitting device. However, when the light-shielding part shields only a part of the light emitted from the first light-emitting part toward the second light-emitting part, a part of the light from the first light-emitting part is emitted from the second light-emitting part. It becomes the excitation light of the substance.

  On the other hand, the second light emitting unit includes at least one kind of light emitting substance that emits light including a component having a longer wavelength than the light emitted from the first light emitting unit when excited by the light emitted from the light source and the light emitted from the first light emitting unit. It is formed including. There is no restriction | limiting in particular also in the shape of this 2nd light emission part, Moreover, it can provide independently in one place, and can also be divided and provided in two or more places. Note that the luminescent material used in the second light emitting unit will also be described in detail later.

  In the second light emitting unit, light emitted from the light emitted from the light source is received, and thereby the luminescent material emits light using the received light as excitation light. Further, when light emitted from the first light emitting unit is incident on the second light emitting unit, the light emitting material emits light using the incident light from the first light emitting unit as excitation light. The emitted light is emitted outside the light emitting device as a component of light emitted by the light emitting device.

  In addition, it is desirable that both the first light emitting unit and the second light emitting unit are open to the outside on the light emitting surface. Here, the light emitting surface means a surface from which the light emitting device emits light in a predetermined direction. Therefore, the light emitted from the light source, the first light emitting unit, and the second light emitting unit is emitted from the light emitting surface in a predetermined direction. Note that the shape of the light exit surface is arbitrary, and it is desirable that the light exit surface has an appropriate shape such as a flat surface, a curved surface, or an uneven surface, depending on the application. Also, normally, even when light emitted from the light emitting device is emitted in a plurality of directions or in a radial manner within a predetermined angular range, the strongest light is emitted in a predetermined direction. Yes.

  In addition, the first light emitting unit and the second light emitting unit being open means that light emitted from the first and second light emitting units in a predetermined direction is emitted without being shielded by other members. Means that. More specifically, light emitted in a predetermined direction from the first light emitting unit emits light without being blocked by the light source, the light shielding unit, the second light emitting unit, and the frame (if the light emitting device includes a frame). The light emitted to the outside of the device, and the light emitted from the second light emitting unit in a predetermined direction includes a light source, a light shielding unit, a first light emitting unit, and a frame (if the light emitting device includes a frame) This means that the light is emitted to the outside of the light emitting device without being shielded. In addition, a protective layer is formed on the light emitting surface or a cover is attached to the light emitting device, and light emitted from the first and second light emitting units is emitted to the outside of the light emitting device through other members. Even in this case, it is assumed that the first and second light emitting portions are open as long as light emitted from other members such as a protective layer and a cover can be transmitted.

  When the first light emitting unit and the second light emitting unit are opened on the light emitting surface as described above, the light emitted from the first light emitting unit and the light emitted from the second light emitting unit are respectively transmitted to other light emitting substances. The degree to which the strength is weakened by being absorbed or shielded by other members can be reduced (or eliminated). Therefore, the light emission efficiency of the light emitting device can be increased, and variations in light components emitted from the light emitting device can be reduced, so that the color rendering properties of the light emitting device can be improved. In addition, since light can be emitted from the light emitting device using the three primary colors of blue light, red light, and green light, the present invention can be achieved by appropriately selecting the light source, the first light emitting unit, and the second light emitting unit. The color reproducibility of the light emitting device can be made excellent.

[I-1-4. Shading part]
The light shielding portion prevents light emitted from the first light emitting portion from entering the second light emitting portion. The light-shielding part only needs to prevent at least a part of the light emitted from the first light-emitting part from entering the second light-emitting part, but usually the light emitted from the light-emitting device in a predetermined direction. However, it is only necessary to prevent the light emitted from the first light emitting part from entering the second light emitting part to such an extent that the light emitting efficiency and the color rendering properties are sufficiently high to withstand practical use. Furthermore, it is preferable that all light emitted from the first light emitting unit does not enter the second light emitting unit. Thereby, since it can prevent that the light emitted from the 1st light emission part is consumed as excitation light of a 2nd light emission part, the fall of the intensity | strength of the light which a 1st light emission part emits can be suppressed, and light-emitting device Both the luminous efficiency and the color rendering properties can be improved.

  In this case, the light shielding part is preferably formed so as to reflect at least a part of the light emitted from the first light emitting part. Furthermore, it is more preferable that the first light emitting unit is formed so as to be able to reflect all of the light that hits the light blocking unit. Thereby, the light emitted from the first light emitting unit can be used effectively, and the light emission efficiency and color rendering of the light emitting device can be further improved.

  In this connection, the light shielding part is preferably formed so as to be able to reflect at least part of the light emitted from the second light emitting part, and all of the light emitted from the second light emitting part and hitting the light shielding part. It is more preferable that it is formed so that it can be reflected. Thereby, the light emitted from the second light emitting unit can also be used effectively, and the light emission efficiency and color rendering of the light emitting device can be further improved.

  Further, the light shielding part is preferably formed so as to be able to reflect at least part of the light emitted from the light source, and is formed so as to be able to reflect all of the light emitted from the light source and hitting the light shielding part. It is more preferable. Thereby, the light emitted from the light source can be used effectively, and the light emission efficiency and color rendering of the light emitting device can be further improved.

  Specifically, at least part of the surface of the light-shielding portion that is struck by light components (that is, light emitted from any one of the light source, the first light-emitting portion, and the second light-emitting portion). The reflectance of light is preferably increased, and in particular, the reflectance of light in the entire visible light region is preferably increased. Therefore, like the frame, at least the surface that is exposed to light is preferably formed of a material having high reflectance. Specific examples include forming the entire light-shielding part or the surface of the light-shielding part with a material (such as an injection shaping resin) containing a material having a high reflectance such as glass fiber, alumina powder, titania powder and the like.

In addition, the specific method for increasing the reflectance of the surface of the light shielding part is arbitrary. In addition to selecting the material of the light shielding part itself as described above, for example, a metal or alloy having a high reflectance such as silver, platinum, aluminum, etc. The light reflectance can also be increased by plating with.
In addition, although the part which raises a reflectance may be the whole light shielding part or a part, it is the whole surface of the part which the light emitted from a light source, a 1st light emission part, and a 2nd light emission part hits normally It is desirable that the reflectance of the is increased.

  The shape of the light-shielding part is not particularly limited as long as it can prevent at least part of the light emitted from the first light-emitting part from entering the second light-emitting part, and can be formed in an arbitrary shape. For example, you may form as members, such as plate shape, net shape, and mesh shape, which partition between the 1st light emission part and the 2nd light emission part. Further, the light shielding portion may be formed integrally with the frame or may be formed separately. However, in general, it is preferable to set the position of the light shielding unit so that the light emitting device can emit the target light according to the light emission intensity of the first light emitting unit and the second light emitting unit.

  In addition, it is easy to manufacture the light emitting device by providing the frame with a plurality of recesses (such as cup-shaped depressions) and providing the light source and the first light emitting unit or the second light emitting unit for each recess. In terms, it is preferable. In this case, the wall portion of the frame that divides each concave portion functions as a light shielding portion. A display device using this form will be described in detail in the third embodiment.

  Further, the material of the light shielding part is not limited as long as it can prevent at least a part of the light emitted from the first light emitting part from entering the second light emitting part, and can be formed of any material. For example, an inorganic material such as a metal, an alloy, or glass, a synthetic resin, an organic material such as carbon, or the like can be used depending on the application. In particular, a material that reflects the light emitted from the first light emitting unit and the second light emitting unit as described above and does not absorb the light emitted from the first light emitting unit and the second light emitting unit is preferable.

  In the light emitting device of the present invention, a light shielding portion is provided between the first light emitting portion and the second light emitting portion, thereby preventing light emitted from the first light emitting portion from entering the second light emitting portion. ing. Thereby, the luminous efficiency and color rendering of the light emitting device of the present invention can be improved. Hereinafter, the mechanism will be described in detail.

  Conventionally, when part of the light emitted from the first light emitting unit is emitted toward the second light emitting unit, the light emitted from the first light emitting unit is incident on the second light emitting unit, and the second light emitting unit emits a luminescent material. Absorbed the light from the first light emitting part as excitation light. As a result, the light emitted from the first light emitting unit is consumed by the second light emitting unit. For this reason, the intensity of the light from the first light emitting unit that should have been emitted to the outside of the light emitting device is reduced, the luminous flux of the light emitted from the light emitting device is reduced, and the light emission efficiency is lowered. In addition, since the light emitted from the first light emitting unit is consumed by the second light emitting unit, the balance of the components of the light emitted from the light emitting device varies and the color reproducibility of the light emitting device is reduced.

  Further, when the light emitted from the light emitting device is intended to have a target color, the configuration as in Patent Document 1 supplements the light from the first light emitting unit absorbed by the second light emitting unit, so that the second light emission. It was necessary to increase the ratio of the light emitting material of the first light emitting part to the light emitting material of the part. However, since the color rendering properties of the light emitted from the light emitting device is determined by the type and usage rate of the light emitting material to be used, in the light emitting device configured as in Patent Document 1, the usage rate of the light emitting material is likely to deviate significantly from the optimum value. For this reason, the color rendering properties of light tend to decrease.

On the other hand, in the light emitting device according to the present invention, the light from the first light emitting unit is prevented from entering the second light emitting unit by the light shielding unit, so that the light from the first light emitting unit is the first light. It can suppress that the intensity | strength becomes weak by being absorbed by 2 light emission parts. Therefore, the light emission efficiency of the light emitting device can be improved as compared with the prior art.
Further, since it is possible to suppress the light emitted from the first light emitting unit from being absorbed by the second light emitting unit, the variation in the components of the light emitted from the light emitting device is reduced, and the color rendering properties of the light emitting device are reduced. Can also be increased. As a result, the color rendering properties and color reproducibility of the light emitting device can be improved.

  Note that some excitation light (mainly light from the light source) can be supplied to the first light emitting unit and the second light emitting unit, and further, light emitted from the light source, the first light emitting unit, and the second light emitting unit is emitted. If it can discharge | emit outside the apparatus, arrangement | positioning of each member which comprises a light-emitting device, a dimension, a shape, etc. can be set arbitrarily.

  For example, the first light emitting unit, the second light emitting unit, the light source, and the frame may be arranged at a distance so as to have a gap therebetween. As a specific example, a gap may be formed between the first light emitting unit and the second light emitting unit. Further, a gap may be formed between one or both of the first light emitting unit and the second light emitting unit and the light source. Further, a gap may be formed between one or both of the first light emitting unit and the second light emitting unit and the light shielding unit.

Further, when a distance is provided between the first light emitting unit and the second light emitting unit, one or both of the first light emitting unit and the second light emitting unit, and the light source so that they do not contact each other, both Other members may be provided between the two. In this case, it is preferable to use a material that transmits desired light, such as glass, a resin such as an epoxy resin, a silicon resin, or the like, as a material for the other members. As a specific example, if a protective layer made of a transparent resin is formed on the entire circumference of the light source, the light from the light source can be converted into a light flux even though the distance between the light source and the first light emitting unit and the second light emitting unit is increased. Since it can be reliably supplied as the excitation light to the first light emitting unit and the second light emitting unit while being kept high, the light source can be protected without reducing the intensity of the light emitted from the light emitting device. .
Further, as described above, the first light emitting unit and the second light emitting unit may have different sizes.

In addition, the light emitting device of the present invention may include members other than the light source, the first light emitting unit, the second light emitting unit, and the frame described above.
For example, a cover for protecting the light emitting device itself may be provided.
Further, for example, a light guide member such as a mirror, a prism, a lens, or an optical fiber for changing the direction of light emitted from the light emitting device may be provided.
Moreover, you may provide the heat sink etc. for discharging | emitting the heat_generation | fever of a light-emitting device.
Further, for example, in order to diffuse each component of light emitted from the light emitting device and prevent color unevenness of the visible light, a light diffusion layer or the like may be provided outside the light emitting surface of the light emitting device. .

[I-2. Composition of light emitting part]
There is no particular limitation on the light-emitting substance used in the light-emitting device of the present invention as long as it absorbs excitation light and can emit light containing a longer wavelength component than the absorbed excitation light. In addition, when the first light emitting unit and the second light emitting unit are formed using a light emitting material, the light emitting material is usually used by mixing with a binder.

[I-2-1. Luminescent substance]
As the light-emitting substance, a known material can be appropriately selected and used according to the use of the light-emitting device. The light emission itself is not limited by any mechanism such as fluorescence or phosphorescence. Moreover, in each of a 1st light emission part and a 2nd light emission part, 1 type of luminescent substances may be used independently and 2 or more types can be used together by arbitrary combinations and a ratio. However, the light emitting material used for the first light emitting unit is selected to emit light containing a component having a longer wavelength than the light emitted from the light source when excited by the light emitted from the light source, and the light emitting material used for the second light emitting unit is the light source And a light source that emits light including a component having a longer wavelength than the light emitted from the first light emitting unit when excited by the light emitted from the first light emitting unit.

The luminescent substance desirably absorbs light having a wavelength of usually 350 nm or more, preferably 400 nm or more, more preferably 430 nm or more, and usually 600 nm or less, preferably 570 nm or less, more preferably 550 nm or less as excitation light.
Further, it is desirable that the light-emitting substance has a wavelength of emitted light of usually 400 nm or more, preferably 450 nm or more, more preferably 500 nm or more, and usually 750 nm or less, preferably 700 nm or less, more preferably 670 nm or less. .

Among them, in the case of a light emitting substance used for the first light emitting part, the excitation light has a wavelength of usually 350 nm or more, preferably 400 nm or more, more preferably 430 nm or more, and usually 520 nm or less, preferably 500 nm or less, more preferably 480 nm or less. It is desirable to absorb the light.
In addition, the light-emitting substance used in the first light-emitting portion has a wavelength of emitted light of usually 400 nm or more, preferably 450 nm or more, more preferably 500 nm or more, and usually 600 nm or less, preferably 570 nm or less, more preferably 550 nm or less. Things are desirable.

On the other hand, in the case of a luminescent substance used for the second light emitting part, the wavelength of the excitation light is usually 400 nm or more, preferably 450 nm or more, more preferably 500 nm or more, and usually 600 nm or less, preferably 570 nm or less, more preferably 550 nm or less. It is desirable to absorb the light.
In addition, the light emitting substance used for the second light emitting part has a wavelength of emitted light of usually 550 nm or more, preferably 580 nm or more, more preferably 600 nm or more, and usually 750 nm or less, preferably 700 nm or less, more preferably 670 nm or less. Things are desirable.

  Further, it is preferable to use a luminescent substance having a luminous efficiency of usually 40% or more, preferably 45% or more, more preferably 50% or more, still more preferably 55% or more, and most preferably 60% or more. The luminous efficiency shown here is a value expressed as a product of quantum absorption efficiency and internal quantum efficiency.

  Hereinafter, a light emitting material suitable for use in the light emitting device of the present invention will be exemplified and described for each light emitting section. However, the light-emitting substance is not limited to the following examples, and it is within the scope of the present invention whether each exemplified light-emitting substance is used in the first light-emitting part or the second light-emitting part. Can be selected arbitrarily.

(Example of a material suitable for the light emitting material of the first light emitting part)
(First Example of First Light Emitting Unit)
As a first example of a light emitting material suitable for the light emitting material of the first light emitting unit, a phosphor represented by the following formula (1) can be given.
M ¹ _a M ² _b M ³ _c O _d (1)

In the above formula (1), M ¹ represents a divalent metal element, M ² represents a trivalent metal element, M ³ represents a tetravalent metal element, and a, b, c, and d are in the following ranges, respectively. Is the number of
2.7 ≦ a ≦ 3.3
1.8 ≦ b ≦ 2.2
2.7 ≦ c ≦ 3.3
11.0 ≦ d ≦ 13.0

M ¹ in the above formula (1) is a divalent metal element, and is at least one selected from the group consisting of Mg, Ca, Zn, Sr, Cd, and Ba from the viewpoint of luminous efficiency and the like. Is more preferable, and Mg, Ca, or Zn is further preferable, and Ca is particularly preferable. In this case, Ca may be a single system or a composite system with Mg. Basically, M ¹ is preferably composed of the elements that are preferred in the above, but may contain other divalent metal elements as long as the performance is not impaired.

M ² in the above formula (1) is a trivalent metal element, and is selected from the group consisting of Al, Sc, Ga, Y, In, La, Gd, and Lu from the same surface as M ^1. At least one of them is preferable, Al, Sc, Y, or Lu is more preferable, and Sc is particularly preferable. In this case, Sc may be a single system or a composite system with Y or Lu. Basically, M ² is preferably composed of the elements that are preferred in the above, but may contain other trivalent metal elements as long as the performance is not impaired.

Furthermore, although M ³ in the above formula (1) is a tetravalent metal element, it is preferable that at least Si is contained from the same surface as M ¹ and M ² . Furthermore, it is desirable that the tetravalent metal element represented by M ³ is usually 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more Si.

In the above formula (1), the specific example of the tetravalent metal element M ³ other than Si is preferably at least one selected from the group consisting of Ti, Ge, Zr, Sn, and Hf. More preferably, it is at least one selected from the group consisting of Zr, Sn, and Hf, and particularly preferably Sn. In particular, it is preferable that M ³ is Si. Basically, M ³ is preferably composed of the elements that are preferred in the above, but may contain other tetravalent metal elements as long as the performance is not impaired.
In the present specification, includes a range that does not impair the performance, with respect to each of the above M ^1, M ^2, M ^3, usually 10 mol% or less, preferably 5 mol% or less, more preferably 1 mol% or less It means including.

The crystal structure of the phosphor is usually a garnet crystal structure, which is generally a body center in which a is 3, b is 2, c is 3, and d is 12 in the above formula (1). It is a cubic lattice crystal. However, here, the element of the luminescent center ion is replaced by the position of the crystal lattice of one of the metal elements of M ¹ , M ² , or M ³ , or disposed in the gap between the crystal lattices. In Formula (1), a may be 3, b is 2, c is 3, and d may not be 12. Therefore, a, b, c, and d are 2.7 ≦ a ≦ 3.3, 1.8 ≦ b ≦ 2.2, 2.7 ≦ c ≦ 3.3, 11.0 ≦ d ≦ 13.0, respectively. It is preferable that the number be in the range.

Further, the luminescent center ion contained in the compound matrix of this crystal structure contains at least Ce, and Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Sm are included for fine adjustment of the luminescent properties. , Eu, Tb, Dy, Ho, Er, Tm, and Yb can also include one or more divalent or tetravalent elements selected from the group consisting of Yb. In particular, it is preferable to include one or more divalent to tetravalent elements selected from the group consisting of Mn, Fe, Co, Ni, Cu, Sm, Eu, Tb, Dy, and Yb. Two to three valent Eu or trivalent Tb can be particularly preferably used.
This phosphor is normally excited with light in the wavelength range of 420 nm to 480 nm. The emission spectrum has a peak at 500 to 510 nm and has a wavelength component of 450 to 650 nm.
Note that specific examples of the phosphor described above include Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce, Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce, and the like.

(Second example of first light emitting unit)
As a second example of a light emitting material suitable for use in the first light emitting unit, a phosphor represented by the following formula (2) can be given.
M ¹ _a M ² _b M ³ _c O _d (2)
In the above formula (2), M ¹ is an activator element containing at least Ce, M ² is a divalent metal element, M ³ is a trivalent metal element, and a, b, c, and d are respectively It is a number in the following range.
0.0001 ≦ a ≦ 0.2
0.8 ≦ b ≦ 1.2
1.6 ≦ c ≦ 2.4
3.2 ≦ d ≦ 4.8

M ¹ in the above formula (2) is an activator element contained in the crystal matrix described later, and contains at least Ce. In addition, Cr, Mn, Fe, Co, Ni, Cu, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb are used for the purpose of phosphorescence, chromaticity adjustment, and sensitization. At least one divalent to tetravalent element selected from the group consisting of:

In the above formula (2), the value a representing the content of the activator element M ¹ is 0.0001 ≦ a ≦ 0.2. If the value of a is too small, there are too few emission center ions present in the crystal matrix of the phosphor, and the emission intensity tends to decrease. On the other hand, if the value of a is too large, the emission intensity tends to decrease due to concentration quenching. Therefore, from the viewpoint of light emission intensity, a is preferably 0.0005 or more, more preferably 0.002 or more, and preferably 0.1 or less, more preferably 0.04 or less. In addition, as the Ce content increases, the emission peak wavelength shifts to the longer wavelength side, and the green emission amount with high visibility is relatively increased. From the viewpoint of the balance between the emission intensity and the emission peak wavelength, a is usually 0.004 or more, preferably 0.008 or more, more preferably 0.02 or more, and usually 0.15 or less, preferably 0.1 or less, more preferably 0.08 or less.

Further, M ² in the above formula (2) is a divalent metal element, and is at least one selected from the group consisting of Mg, Ca, Zn, Sr, Cd, and Ba from the viewpoint of luminous efficiency and the like. It is preferable that Mg, Ca or Sr is more preferable, and it is particularly preferable that 50 mol% or more of the element of M ² is Ca.

Further, M ³ in the above formula (2) is a trivalent metal element, but from the same surface as M ² , from the group consisting of Al, Sc, Ga, Y, In, La, Gd, Yb, and Lu. It is preferably at least one selected, more preferably Al, Sc, Yb, or Lu, even more preferably Sc, or Sc and Al, or Sc and Lu, and the element of M ³ It is particularly preferable that 50 mol% or more of is Sc.

The base crystal of the phosphor is generally a crystal represented by a composition formula M ² M ³ ₂ O ₄ , which is composed of a divalent metal element M ² , a trivalent metal element M ³ and oxygen. Therefore, the chemical composition ratio is generally such that b in the above formula (2) is 1, c is 2, and d is 4. However, here, the activator element Ce is replaced with the position of the crystal lattice of the metal element of either M ² or M ³ , or disposed in the gap between the crystal lattices, etc. In (2), b may be 1, c may be 2, and d may not be 4.

  Therefore, in the above formula (2), b is usually 0.8 or more, preferably 0.9 or more, and usually 1.2 or less, preferably 1.1 or less. C is usually 1.6 or more, preferably 1.8 or more, and usually 2.4 or less, preferably 2.2 or less. Furthermore, d is usually 3.2 or more, preferably 3.6 or more, and usually 4.8 or less, preferably 4.4 or less.

In the above formula (2), M ² and M ^3, which respectively represent a divalent and trivalent metal elements, if there are different essentially like emission characteristics and crystal structures, M ² and / or A small part of M ³ is a metal element having a valence of monovalent, tetravalent, or pentavalent, and the charge balance can be adjusted. Further, a small amount of anion, for example, a halogen element ( F, Cl, Br, I), nitrogen, sulfur, selenium and the like may be contained in the compound.
This phosphor is excited by light in the wavelength range of 420 nm to 480 nm, and is most efficient particularly at 440 to 470 nm. The emission spectrum has a peak at 490 to 550 nm and has a wavelength component of 450 to 700 nm.

(Other examples of the first light emitting unit)
Other examples of light emitting materials suitable for use in the first light emitting part include Y ₃ (Al, Ga) ₅ O ₁₂ : Ce, (Ba, Ca, Sr) MgAl ₁₀ O ₁₇ : Eu, and (Ba, Mg, Ca, Sr) ₅ (PO) ₄ Cl: Eu, (Ba, Ca, Sr) ₃ MgSi ₂ O ₈ : Eu, and the like, and (Ba, Ca, Sr) MgAl ₁₀ O ₁₇ : Eu, Mn, (Ba, Ca, Sr) Al ₂ O ₄ : Eu, (Ba, Ca, Sr) Al ₂ O ₄ : Eu, Mn, (Ca, Sr) Al ₂ O ₄ : Eu, formula _{Ca x Si 12- (m + n} ) Al (m + n) O n n 16-n: Eu ( where, 0.3 <x <1.5,0.6 <m <3,0 ≦ n <1.5) Examples include, but are not limited to, substances having an emission peak at a wavelength of 500 nm to 600 nm, such as α-sialon activated by Eu. It is not.
Moreover, the above-mentioned fluorescent substance may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

However, among the exemplified phosphors, those having a garnet crystal structure are preferable because they are hardly deteriorated against heat, light, and water. Specific examples of the phosphor having such a garnet crystal structure include the phosphor exemplified as the first example of the phosphor emitting green light, and Y ₃ (Al, Ga) ₅ O ₁₂ : Ce. .

(Example of a material suitable for the light emitting material of the second light emitting part)
(First Example of Second Light Emitting Unit)
As a first example of a light-emitting substance suitable for the light-emitting substance of the second light-emitting portion, a phosphor represented by the following formula (3) can be given.
M _a A _b D _c E _d X _e Formula (3)

  In the above formula (3), M is one or more elements selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb. A represents at least Eu, A represents one or more elements selected from the group consisting of divalent metal elements other than M element, and D represents a group consisting of tetravalent metal elements Represents one or more elements selected, E represents one or more elements selected from the group consisting of trivalent metal elements, and X represents a group consisting of O, N, and F Represents one or more elements selected from

In the above formula (3), a, b, c, d, and e are numbers in the following ranges, respectively.
0.00001 ≦ a ≦ 0.1
a + b = 1
0.5 ≦ c ≦ 4
0.5 ≦ d ≦ 8
0.8 × (2/3 + 4/3 × c + d) ≦ e
e ≦ 1.2 × (2/3 + 4/3 × c + d)

  In the above formula (3), M contains at least Eu and is one or more selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb. Among these elements, among them, one or more elements selected from the group consisting of Mn, Ce, Sm, Eu, Tb, Dy, Er, and Yb are preferable, and Eu is more preferable. .

In the above formula (3), A is one or more elements selected from the group consisting of divalent metal elements other than the M element, and among these, Mg, Ca, Sr, and Ba are included. It is preferably one or more elements selected from the group, and more preferably Ca or a composite system of Ca and Sr.
Furthermore, in the above formula (3), D is one or more elements selected from the group consisting of tetravalent metal elements, among which Si, Ge, Sn, Ti, Zr, and Hf. It is preferably one or more elements selected from the group, and more preferably Si.

In the above formula (3), E is one or more elements selected from the group consisting of trivalent metal elements, among which B, Al, Ga, In, Sc, Y, La Preferably, it is one or more elements selected from the group consisting of Gd, Lu, and more preferably Al.
Further, in the above formula (3), X is one or more elements selected from the group consisting of O, N, and F. Among them, it is preferable that X or N and O are included.

  In the above formula (3), a represents the content of the element M serving as the emission center, and the ratio a of the number of atoms of M and (M + A) in the phosphor is a {where a = (number of M atoms) / It is preferable that (the number of M atoms + the number of A atoms)} be 0.00001 or more and 0.1 or less. If the a value is smaller than 0.00001, the number of Ms as the light emission centers is small, and the light emission luminance may be lowered. When the a value is larger than 0.1, there is a risk that the brightness is lowered due to concentration quenching due to interference between M ions. In particular, when M is Eu, the a value is preferably 0.002 or more and 0.03 or less in that light emission luminance is increased.

  Furthermore, in said formula (3), c is content of D elements, such as Si, and is the quantity shown by 0.5 <= c <= 4. Preferably, 0.5 ≦ c ≦ 1.8, more preferably c = 1. When c is smaller than 0.5 or larger than 4, the light emission luminance may be lowered. Further, in the range of 0.5 ≦ c ≦ 1.8, the emission luminance is high, and among them, c = 1 is particularly high.

  Furthermore, in said formula (3), d is content of E elements, such as Al, and is the quantity shown by 0.5 <= d <= 8. Preferably, 0.5 ≦ d ≦ 1.8, more preferably d = 1. When the d value is smaller than 0.5 or larger than 8, there is a possibility that the light emission luminance is lowered. Further, in the range of 0.5 ≦ d ≦ 1.8, the light emission luminance is high, and in particular, d = 1 is particularly high in light emission luminance.

  Further, in the above formula (3), e is the content of X element such as N, and is 0.8 × {(2/3) + (4/3) × c + d} or more 1.2 × {(2 / 3) + (4/3) × c + d} is an amount shown below. More preferably, e = 3. If the value of e is out of the above range, the light emission luminance may decrease.

Among the above compositions, a preferable composition having high emission luminance includes at least Eu in the M element, Ca in the A element, Si in the D element, Al in the E element, and N in the X element. Is included. Among them, an inorganic compound in which the M element is Eu, the A element is Ca, the D element is Si, the E element is Al, and the X element is N or a mixture of N and O is desirable.
This phosphor is excited by light having a wavelength of at least 580 nm or less, and has the highest efficiency, particularly in the wavelength range of 400 nm to 550 nm. Therefore, the phosphor emits well the light emitted from the first light emitting unit. The emission spectrum has a peak in the wavelength range of 580 nm to 720 nm.

(Second Example of Second Light Emitting Unit)
As a second example of the light emitting material suitable for the light emitting material of the second light emitting unit, a phosphor represented by the following formula (4) can be given.
_{Eu a Ca b Sr c M d} S e ··· Equation (4)
In the above formula (4), M represents at least one element selected from Ba, Mg, and Zn, and a, b, c, d, and e are numbers in the following ranges, respectively.
0.0002 ≦ a ≦ 0.02
0.3 ≦ b ≦ 0.9998
0 ≦ d ≦ 0.1
a + b + c + d = 1
0.9 ≦ e ≦ 1.1

From the viewpoint of thermal stability, the preferable range of a in the above formula (4) is usually 0.0002 or more, preferably 0.0004 or more, and usually 0.02 or less.
In terms of temperature characteristics, the preferable range of a in the above formula (4) is usually 0.0004 or more, usually 0.01 or less, preferably 0.007 or less, more preferably 0.005. Hereinafter, more preferably 0.004 or less.

Furthermore, in terms of light emission intensity, the preferred range of a in the above formula (4) is usually 0.0004 or more, preferably 0.001 or more, and usually 0.02 or less, preferably 0.008 or less. Is desirable. If the content of the luminescent center ion Eu ²⁺ is smaller than the above range, the luminescence intensity tends to be small. On the other hand, even if it is larger than the above range, the luminescence intensity tends to decrease due to a phenomenon called concentration quenching.
Speaking of a preferable range of a in the above formula (4) that has all of thermal stability, temperature characteristics, and emission intensity, it is usually 0.0004 or more, preferably 0.001 or more, and usually 0.004 or less. A range is desirable.

In the basic crystal _{Eu a Ca b Sr c M d} S e of the equation (4), Eu, Ca, but the molar ratio of the anion site occupied by cations sites and S occupied by Sr or M is one-to-one Even if some cation deficiency or anion deficiency occurs, there is no significant effect on the fluorescence performance for this purpose. Therefore, the molar ratio e of the anion sites occupied by S is within the range of 0.9 to 1.1. The basic crystals can be used.

  In the phosphor of the above formula (4), M representing at least one element selected from Ba, Mg, and Zn is not necessarily an essential element for the present invention, but 0 ≦ d ≦ 0.1 at a molar ratio d of M. Even if it is contained in the chemical substance of the above formula (4) in the ratio, the object of the present invention can be achieved.

Furthermore, even if elements other than Eu, Ca, Sr, Ba, Mg, Zn, and S are contained in the chemical substance of the formula (4) in an amount of 1% or less as an impurity, there is no problem in use.
This phosphor is excited by light of 600 nm or less, and is particularly efficient at 400 nm to 550 nm. Therefore, the phosphor emits light emitted from the first light emitting part well. The emission spectrum has a peak at 620 nm to 680 nm.

(Other examples of the second light emitting unit)
Other examples of the light emitting material suitable for use in the second light emitting part are not particularly limited as long as the emission wavelength is 550 nm to 750 nm and the emission wavelength is longer than that of the first light emitting part. formula _{Ca x Si 12- (m + n} ) Al (m + n) O n n 16-n: Eu ( where, 0.3 <x <1.5,0.6 <m <3,0 ≦ n Α sialon activated by Eu represented by <1.5), Ca ₂ Si ₅ N ₈ : Eu, CaSi ₇ N ₁₀ : Eu, a europium complex emitting fluorescence, or the like can be used.
Moreover, the above-mentioned fluorescent substance may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

(E.g. particle size of luminescent material)
The luminescent material is usually used in the form of particles. At this time, the particle diameter of the luminescent material particles is usually 150 μm or less, preferably 50 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less, and most preferably 5 μm or less. Beyond this range, the emission color variation of the light emitting device becomes large, and when the light emitting substance and the sealing material are mixed, it may be difficult to uniformly apply the light emitting substance. Moreover, it is 0.001 micrometer or more normally, Preferably it is 0.01 micrometer or more, More preferably, it is 0.1 micrometer or more, More preferably, it is 1 micrometer or more, Most preferably, it is 2 micrometers or more. Below this range, the luminous efficiency decreases.

  The volume ratio of the light emitting material of the second light emitting unit to the light emitting material of the first light emitting unit is arbitrary, but is usually 0.05 or more, preferably 0.1 or more, more preferably 0.2 or more, Usually, it is 1 or less, preferably 0.8 or less, more preferably 0.5 or less. If this ratio is too large or too small, it is difficult to obtain preferable white light emission.

  In the case of forming the first light emitting unit and the second light emitting unit without using a binder, for example, a light emitting material is fired to produce a fired body, and the fired body is used as it is for the first light emitting part and the second light emitting part. Can be used. In addition, for example, even when glass is manufactured using a light emitting material or a single crystal of a light emitting material is used, the first light emitting unit and the second light emitting unit can be manufactured without using a binder. Even when the binder is not used, other components such as an additive can coexist in the first light emitting part and the second light emitting part.

  Further, the second light emitting unit includes a light emitting substance, a binder, and other components that emit light including a component having a longer wavelength than the light emitted from the first light emitting unit when excited by the light emitted from the light source and the first light emitting unit. In addition, the light emitting substance of the first light emitting unit may be mixed. However, in order to obtain a larger luminous flux, the concentration of the luminescent material of the first light emitting unit included in the second light emitting unit is preferably small, and the second light emitting unit does not contain the luminescent material of the first light emitting unit. It is more preferable.

  On the other hand, the first light-emitting part normally does not contain the light-emitting substance of the second light-emitting part, but the light-emitting substance of the second light-emitting part is contained as long as the luminous flux of the light emitted from the first light-emitting part is not reduced. In general, it is desirably 40% by volume or less, and more desirably, the light emitting material of the second light emitting part is not contained at all. That is, even if the light emitting material in the second light emitting unit is excited by the light emitted from the first light emitting unit, the light emitted from the light emitting material in the first light emitting unit is emitted from the first light emitting unit to the second light emission. The luminescent material in each light emitting part should be selected so that the luminescent material in the part does not absorb too much.

[I-2-2. Binder]
As described above, the first light emitting unit and the second light emitting unit may contain a binder in addition to the light emitting material. The binder is usually used for collecting powdery or particulate luminescent materials or attaching them to a frame. There is no restriction | limiting about the binder used for the light-emitting device of this invention, A well-known thing can be used arbitrarily.

  However, the light emitting device is of a transmission type, that is, the light emitted from the light source, the first light emitting unit, and the second light emitting unit is transmitted through the first light emitting unit or the second light emitting unit and emitted to the outside of the light emitting device. In this case, it is desirable to select a binder that transmits each component of light emitted from the light emitting device.

  As an example of the binder, an inorganic material such as glass can be used in addition to a resin. Specific examples thereof include organic synthetic resins such as epoxy resins and silicon resins, and inorganic materials such as polysiloxane gel and glass.

Further, when a resin is used as the binder, the viscosity of the resin is arbitrary, but it is desirable to use a binder having an appropriate viscosity according to the particle size and specific gravity of the luminescent material to be used, in particular, the specific gravity per surface area. . For example, when an epoxy resin is used as a binder and the particle size of the luminescent material particles is 2 μm to 5 μm and the specific gravity is 2 to 5, usually, when an epoxy resin having a viscosity of 1 to 10 Pas is used, light emission This is preferable because the substance particles can be well dispersed.
In addition, a binder may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

[I-2-3. Usage ratio of luminescent materials]
When a binder is used as the light emitting material, the ratio of the light emitting material to the binder is not limited, but the ratio of the light emitting material to the binder is usually 0.01 or more, preferably 0.05 or more, more preferably 0 by weight. .1 or more, usually 5 or less, preferably 1 or less, more preferably 0.5 or less.

  However, when the light emitting device is a transmissive type, it is desirable that the luminescent material is appropriately dispersed in the first light emitting unit and the second light emitting unit in order to obtain a higher luminous flux. On the other hand, the light emitting device is of a reflection type (that is, light emitted from the light source, the first light emitting unit, and the second light emitting unit is emitted outside the light emitting device without passing through the first light emitting unit or the second light emitting unit). In order to obtain a higher luminous flux, it is preferable that the luminescent material is packed at a high density. Therefore, the composition of the luminescent material should be set according to the use of the light-emitting device, the type and physical properties of the luminescent material, the type and viscosity of the binder, etc., taking these into consideration.

  Note that the emission color of the light emitted from the light emitting device can be arbitrarily changed by adjusting the ratio of the light emitting materials of the first light emitting unit and the second light emitting unit and the use weight of the light emitting material. As a result, not only the light whose color coordinates are (x = 0.333, y = 0.333) but also (x = 0.47, y = 0.42), (x = 0.35, y = 0.25). ), (X = 0.25, y = 0.30), (x = 0.30, y = 0.40), and other intermediate colors are also possible.

[I-2-4. Other ingredients]
In addition, the light emitting material may contain other components, and the first light emitting portion and the second light emitting portion may be formed of the light emitting material, a binder and other components used as appropriate.
There is no restriction | limiting in particular in another component, A well-known additive can be used arbitrarily. Specifically, for example, when controlling the light distribution characteristics and color mixing of the light emitting device, it is preferable to use a diffusing agent such as alumina or yttria as the other component. For example, when the luminescent material is filled with a high density, it is preferable to use a binder such as calcium pyrophosphate or barium calcium borate as the other component.

[I-2-5. Method for manufacturing light emitting part]
There is no restriction | limiting in particular in the preparation methods of a 1st light emission part and a 2nd light emission part, It can produce by arbitrary methods. Hereinafter, a method for manufacturing the first light-emitting portion and the second light-emitting portion will be described as an example. However, the first light-emitting portion and the second light-emitting portion can also be manufactured by a method other than the manufacturing method described below.
For example, the first light emitting unit and the second light emitting unit are prepared by dispersing a light emitting material and a binder and other components appropriately used in a dispersion medium to prepare a slurry, and applying the prepared slurry to a substrate such as a frame, The slurry can be formed by drying.

  The slurry is prepared by mixing the luminescent material and other components such as binders and additives that are used appropriately in a dispersion medium. Note that the name of the slurry may be changed to a paste, a pellet, or the like depending on the type of the binder, but in this specification, these are referred to as a slurry.

  There is no restriction | limiting in the dispersion medium used for slurry preparation, A well-known dispersion medium can be used arbitrarily. Specific examples thereof include chain hydrocarbons such as n-hexane, n-heptane, and solvesso, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as trichloroethylene and perchloroethylene, methanol, ethanol, isopropanol, Alcohols such as n-butanol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate and n-butyl acetate, ethers such as cellosolve, butylsolve and cellosolve acetate, water and any aqueous solution An aqueous solvent etc. are mentioned.

Next, the prepared slurry is applied to a substrate such as a frame. The application method is arbitrary, but for example, a technique such as dispensing or potting can be used.
In addition, when apply | coating a slurry directly to a flame | frame, the order of application | coating with the slurry used as a 1st light emission part and the slurry used as a 2nd light emission part is arbitrary, and you may apply any first. Moreover, you may apply | coat simultaneously.

  After the application, the dispersion medium is dried to produce the first light emitting part and the second light emitting part. Any drying method can be used. For example, natural drying, heat drying, vacuum drying, baking, ultraviolet irradiation, electron beam irradiation, or the like may be used. Among these, baking at a temperature of several tens of degrees Celsius to hundreds of tens of degrees Celsius is preferable because the dispersion medium can be easily and reliably removed with inexpensive equipment.

  As described above, when the density of the luminescent material is increased for the purpose of manufacturing a reflective light-emitting device, it is preferable to mix a binder as another component with the slurry. Moreover, when applying the slurry which mixed the binder, it is desirable to use application methods, such as a screen printing type and inkjet printing. This is because it is easy to divide the region between the first light emitting unit and the second light emitting unit. Of course, when a binder is used, it may be applied by a normal application method.

  There is also a method for producing the first light emitting part and the second light emitting part without using slurry. For example, a 1st light emission part and a 2nd light emission part can also be produced by mixing a luminescent substance, the binder used suitably, and another component, and knead-molding. Furthermore, when molding, for example, the molding can be performed by press molding, extrusion molding (T-die extrusion, inflation extrusion, blow molding, melt spinning, profile extrusion, etc.), injection molding, or the like.

  Furthermore, when the binder is a thermosetting material such as an epoxy resin or a silicon resin, the binder before curing, the luminescent material and other components used as appropriate are mixed and molded, and then the binder is heated by heating. The first light emitting part and the second light emitting part can be manufactured by curing. Further, when the binder is UV curable, the first light emitting part and the second light emitting part can be produced by curing the binder resin by irradiating UV light instead of heating in the above method.

  By the way, the first light emitting unit and the second light emitting unit may be manufactured in a series of steps when manufacturing the light emitting device, but the first light emitting unit and the second light emitting unit are separately prepared in advance, The light emitting device may be completed after being incorporated into a frame or the like. Furthermore, it is also possible to prepare a unit that combines the frame and one of the first light emitting unit and the second light emitting unit, and to complete the light emitting device by combining these units.

  In this connection, a method of providing a light shielding portion is also arbitrary. For example, after the first light emitting unit and the second light emitting unit are provided first, a light shielding unit may be provided later between them, or the light shielding unit is formed in advance in the frame and is divided by the light shielding unit. You may make it provide a 1st light emission part and a 2nd light emission part after that by apply | coating the said slurry etc. to each hollow.

[I-3. Embodiment]
Hereinafter, the present invention will be described with reference to embodiments of the present invention. However, the present invention is not limited to the following embodiments, and may be arbitrarily modified and implemented without departing from the gist of the present invention. it can.

[I-3-1. First Embodiment]
1 (a) and 1 (b) are diagrams schematically showing a main part of a light emitting device as a first embodiment of the present invention, FIG. 1 (a) is a sectional view thereof, and FIG. b) is an exploded perspective view with the partition plate removed for explanation.
As shown in FIGS. 1A and 1B, a light emitting device 1 according to the present embodiment includes a frame 2, a blue LED (blue light emitting unit) 3 that is a light source, and a green light emitting that is a first light emitting unit. Part 4, a red light emitting part 5 as a second light emitting part, and a partition plate 6 as a light shielding part.

  The frame 2 is a resin base for holding the blue LED 3, the green light emitting unit 4, the red light emitting unit 5, and the partition plate 6. On the upper surface of the frame 2, a trapezoidal concave portion (dent) 2A having an opening on the upper side in the figure is formed. Thereby, since the frame 2 has a cup shape, the light emitted from the light emitting device 1 can have directivity, and the emitted light can be used effectively. The size of the recess 2A of the light emitting device 1 (the slope of the slope, the depth from the opening to the bottom surface, etc.) is such that the light emitting device 1 can emit light in a predetermined direction (here, upward in the figure). The dimensions are set.

In addition, an electrode (not shown) to which power is supplied from the outside of the light emitting device 1 is provided at the bottom of the recess 2A, and power can be supplied to the blue LED 3 from this electrode.
Furthermore, the inner surface of the recess 2A of the frame 2 is enhanced in the reflectance of light in the entire visible light region by metal plating, so that the light hitting the inner surface of the recess 2A of the frame 2 can also be transmitted from the light emitting device 1 in a predetermined direction. It can be released toward. Needless to say, metal plating should not be short-circuited.

  A blue LED 3 is installed as a light source at the bottom of the recess 2 </ b> A of the frame 2. The blue LED 3 is an LED that emits blue light when supplied with electric power. Part of the blue light emitted from the blue LED 3 is absorbed as excitation light by the light emitting material (here, fluorescent material) in the green light emitting unit 4 and the red light emitting unit 5, and another part is the light emitting device 1. Is emitted in a predetermined direction (here, upward in the figure).

  In addition, as described above, the blue LED 3 is installed at the bottom of the recess 2A of the frame 2. Here, a silver paste (a mixture of silver particles in an adhesive) is provided between the frame 2 and the blue LED 3. ) 7, whereby the blue LED 3 is installed on the frame 2. Further, the silver paste 7 also plays a role of radiating heat generated in the blue LED 3.

  Further, a gold wire 8 for supplying power to the blue LED 3 is attached to the frame 2. In other words, the blue LED 3 and the electrode (not shown) provided on the bottom of the recess 2A of the frame 2 are connected by wire bonding using the wire 8, and power is supplied to the blue LED 3 by energizing the wire 8. The blue LED 3 emits blue light.

Furthermore, a green light emitting part 4 as a first light emitting part and a red light emitting part 5 as a second light emitting part are provided in the recess 2A of the frame 2.
The concave portion 2A is filled with the green light emitting portion 4 and the red light emitting portion 5, and the surface of the green light emitting portion 4 and the red light emitting portion 5 facing the outside of the light emitting device 1 through the opening of the concave portion 2A emits light. The device 1 functions as a light emission surface 1A that emits light in a predetermined direction. That is, blue light emitted from the blue LED 3, green light emitted from the green light emitting unit 4, and red light emitted from the red light emitting unit 5 are emitted in a predetermined direction from the light emitting surface 1A. ing.

  The green light emitting part 4 is formed of a green phosphor and a transparent resin. The green phosphor is a luminescent material of the green light emitting unit 4 and is a fluorescent material that is excited by blue light emitted from the blue LED 3 and emits green light having a longer wavelength than blue light. Further, the transparent resin is a binder of the green light emitting unit 4, and here, an epoxy resin which is a synthetic resin capable of transmitting visible light over the entire wavelength region is used.

  The green light emitting portion 4 is formed so as to fill the left portion in the figure from the bottom of the recess 2A to the opening. Moreover, the green light emission part 4 is formed so that the upper surface of blue LED3 and side surfaces other than the right side surface in the figure may be covered. Further, the green light emitting portion 4 has a larger volume than the red light emitting portion 5 in the recess 2A.

  Furthermore, the green light emission part 4 has the 1st light-projection surface 4A in the opening part of the recessed part 2A. The first light exit surface 4A is an upper surface in the drawing of the green light emitting unit 4 formed in a planar shape, and overlaps a plane formed by the upper surface of the frame 2. The first light emitting surface 4A is a surface that emits light emitted from the green light emitting unit 4 in a predetermined direction outside the light emitting device 1. Blue light emitted from the blue LED 3 is also emitted from the first light emitting surface 4A. To be released. Further, the first light emitting surface 4A, together with a second light emitting surface 5A described later, constitutes a light emitting surface 1A that emits light emitted from the light emitting device 1 to the outside. Thereby, the green light emission part 4 is open | released in 1 A of light-projection surfaces.

  On the other hand, the red light emitting portion 5 is formed of a red phosphor and a transparent resin. The red phosphor is a light emitting material of the red light emitting unit 5 and is excited by blue light emitted from the blue LED 3 and green light emitted from the green light emitting unit 4 to emit red light having a longer wavelength than that of green light. It is a fluorescent substance that emits light. Further, the transparent resin is a binder of the red light emitting unit 5, and here, like the green light emitting unit 4, an epoxy resin that can transmit visible light is used.

  The red light emitting portion 5 is formed so as to fill the right portion in the figure from the bottom of the recess 2A to the opening. As described above, the green light emitting portion 4 is also formed from the bottom of the recess 2A to the opening. Therefore, in the light emitting device 1, the thickness of the green light emitting portion 4 (the distance in the vertical direction in the figure) and the thickness of the red light emitting portion 5 are formed. Is formed to be substantially equal. Moreover, the red light emission part 5 is formed so that the right side surface of the blue LED 3 in the figure may be covered. Furthermore, the red light emitting unit 5 occupies a smaller volume than the green light emitting unit 4 in the recess 2A.

  Further, the red light emitting unit 5 also has a second light emitting surface 5A at the opening of the recess 2A, as with the green light emitting unit 4. The second light emission surface 5A is the upper surface in the figure of the red light emitting section 5 formed in a planar shape, and overlaps the plane formed by the upper surface of the frame 2. The second light emitting surface 5A is a surface that emits light emitted from the red light emitting unit 5 in a predetermined direction outside the light emitting device 1. Blue light emitted from the blue LED 3 is also emitted from the second light emitting surface 5A. To be released. Further, as described above, the second light exit surface 5A, together with the first light exit surface 4A, constitutes a light exit surface 1A that emits light emitted from the light emitting device 1 to the outside. Thereby, the red light emission part 5 is open | released in 1 A of light-projection surfaces.

  Further, a partition plate 6 is attached between the green light emitting part 4 and the red light emitting part 5 by being inserted into an insertion part 2B formed in the frame 2 as a light shielding part from the opening part of the recess 2A. . The partition plate 6 is formed as a rectangular parallelepiped resin plate extending in the depth direction of the recess 2A from the opening to the vicinity of the blue LED and extending in the width direction of the recess 2A. In addition, the entire surface of the partition plate 6 is subjected to the same plating treatment as that of the frame 2 so that visible light can be efficiently reflected.

  Therefore, most of the light emitted from the green light emitting unit 4 is reflected when it hits the partition plate 6 and does not enter the red light emitting unit 5. Further, most of the light emitted from the red light emitting unit 5 is reflected when it hits the partition plate 6, and does not enter the green light emitting unit 4. However, in the vicinity of the bottom of the concave portion 2A, a very small gap is formed between the bottom surface of the concave portion 2A and the lower end of the partition plate 6, and the green light emitting portion 4 and the red light emitting portion 5 are in contact with each other. . Therefore, in this gap portion where the green light emitting unit 4 and the red light emitting unit 5 are in contact with each other, light can come and go between the green light emitting unit and the red light emitting unit 5 very slightly.

  The light emitting device 1 of the present embodiment is configured as described above. Therefore, when blue light is emitted from the blue LED 3, a part thereof is used as excitation light by the green light emitting unit 4, and green light is emitted from the green light emitting unit 4. The other part of the blue light emitted from the blue LED 3 is used as excitation light by the red light emitting unit 5, and red light is emitted from the red light emitting unit 5. Further, a small amount of the green light emitted from the green light emitting unit 4 enters the red light emitting unit 5 through this gap where the green light emitting unit 4 and the red light emitting unit 5 are in contact with each other, and is absorbed and used as excitation light. Will be. Then, the blue light, the green light, and the red light emitted in this way are each emitted in a predetermined direction from the light emitting surface 1A.

  With such a configuration, the light emitting device 1 can exhibit high luminous efficiency and color rendering. That is, since the partition plate 6 for preventing the light emitted from the green light emitting unit 4 from entering the red light emitting unit 5 is provided between the green light emitting unit 4 and the red light emitting unit 5, the green light emitting unit 4 can suppress the amount of light emitted by the red light emitting unit 5, thereby improving the light emission efficiency and color rendering of the light emitting device 1. In addition, since it is possible to suppress variation in the components of light emitted from the light emitting device 1, the color reproducibility of the light emitting device 1 can be improved.

  The green light emitted from the green light emitting part 4 is incident on the red light emitting part 5 in this gap where the green light emitting part 4 and the red light emitting part 5 are in contact with each other. There is no decline in performance. Of course, if the green light emitted from the green light emitting part 4 is not incident on the red light emitting part 5 at all by partitioning the part other than the part where the blue LED 3 and the red light emitting part 5 are in contact with each other by the partition plate 3, the light is emitted more reliably. Efficiency and color rendering can be improved.

  Further, since the surface of the frame 2 and the surface of the partition plate 6 can reflect all visible light efficiently, blue light emitted from the blue LED 3, green light emitted from the green light emitting unit 4, and red light emitting unit 5. Since the red light emitted from the light is emitted from the light emission surface 1A without being absorbed by the frame 2 or the partition plate 6, each light can be used effectively, and the luminous efficiency can be increased.

[I-3-2. Second Embodiment]
2 (a) and 2 (b) are diagrams schematically showing a main part of a light emitting device as a second embodiment of the present invention, FIG. 2 (a) is a sectional view thereof, and FIG. 2 (b). Is a perspective view thereof. However, in FIG. 2 (a), the green light emitting part 14 and the red light emitting part 15 are shown with a large thickness for the sake of explanation, but the green light emitting part 14 and the red light emitting part 15 are not so visually confirmed. It is assumed that it is a thin film-like portion.
As shown in FIGS. 2A and 2B, the light emitting device 11 of the present embodiment includes a frame 12, a blue LED (blue light emitting unit) 13 that is a light source, and a green light emitting that is a first light emitting unit. Part 14, a red light emitting part 15 as a second light emitting part, a partition wall 16 and a beam 19.

The frame 12 is a resin base for holding the blue LED 13, the green light emitting unit 14, the red light emitting unit 15, the partition wall 16 and the beam 19, similar to the frame 2 of the first embodiment. In the figure, a trapezoidal recess (dent) 12A having an opening on the upper side is formed. Therefore, as in the first embodiment, the light emitted from the light emitting device 11 can have directivity, and the emitted light can be used effectively.
Further, the frame 12 is provided with metal plating on the surface of the recess 12A so that light hitting the surface of the frame 12 can be emitted from the light emitting device 11 in a predetermined direction (here, upward in the figure). It has become.

  On the upper part of the frame 12, a beam 19 is installed from one side of the upper part of the recess 12A to the other. The beam 19 is formed of a material that transmits at least blue light emitted from the blue LED 13, green light emitted from the green light emitting unit 14, and red light emitted from the red light emitting unit 15. Further, the beam 19 has an electrode (not shown) at the bottom, and power can be supplied to the blue LED 13 through this electrode.

  A blue LED 13 is installed as a light source at the center of the lower surface of the beam 19. The blue LED 13 is the same as the blue LED 3 of the first embodiment, and functions in the same manner, so the description thereof is omitted here. The blue LED 13 is fixed to the beam 19 with a silver paste 17 and is supplied with electric power through an electrode by a wire 18. At this time, the silver paste 17 and the wire 18 of the light emitting device 11 are the same as the silver paste 7 and the wire 8 of the first embodiment, respectively.

Further, on the frame 12, a green light emitting portion 14 as a first light emitting portion and a red light emitting portion 15 as a second light emitting portion are formed in a film shape having the same film thickness. 14 and the red light emitting portion 15 cover the entire inner surface of the recess 12A of the frame 12.
In addition, the light emitting device 11 is set so that a predetermined direction in which light is emitted is an upward direction in the drawing. Therefore, the surface where the green light emitting portion 14 is not in contact with the frame 12 and the partition wall 16, and the red light emitting portion The surface where 15 is not in contact with the frame 12 and the partition wall 16 functions as a light emitting surface 11A from which the light emitting device 11 emits light in a predetermined direction, and the green light emitting portion 14 and the red light emitting portion 15 are respectively The light exit surface 11A is open. Therefore, the blue light emitted from the blue LED 13, the green light emitted from the green light emitting unit 14, and the red light emitted from the red light emitting unit 15 are emitted from the light emitting surface 11A in a predetermined direction. ing. The light emitted from the blue LED 13 is not directly emitted in a predetermined direction, but is once reflected by the frame 12 and emitted to the outside.
The space from the bottom of the recess 12A of the frame 12 to the lower surface of the beam 19 transmits at least a blue light emitted from the blue LED 13, a green light emitted from the green light emitting part 14, and a red light emitted from the red light emitting part 15 (illustrated). (Omitted).

  The green light emitting unit 14 is formed by depositing the same material as that of the green light emitting unit 4 of the first embodiment on the bottom surface and the slope of the recess 12 </ b> A of the frame 12. Further, the green light emitting portion 14 is formed from the right end of the surface of the concave portion 12A to the left side in the drawing (here, the left side from the position corresponding to the left end of the blue LED 13) from the central portion. For this reason, the green light emitting unit 14 has a larger volume than the red light emitting unit 15.

On the other hand, the red light emitting portion 15 is formed by depositing the same material as that of the red light emitting portion 5 of the first embodiment on the surface of the recess 12A of the frame 12. Moreover, the red light emission part 15 is formed in the bottom part and slope in which the green light emission part 14 is not formed of the recessed part 12A surface. Since the green light emitting portion 14 is formed from the right end of the frame 12 to the right side in the drawing rather than the center portion, the red light emitting portion 15 is formed farther from the blue LED 13 than the green light emitting portion 14. Will be.
Therefore, the blue light emitted from the blue LED 13 is more incident on the green light emitting unit 14 than on the red light emitting unit 15.

  Further, in the light emitting device 11 of the present embodiment, a partition wall 16 is formed at a boundary portion between the green light emitting unit 14 and the red light emitting unit 15. The partition wall 16 extends in the depth direction of the concave portion 12A from the bottom surface of the concave portion 12A to the vicinity of the blue LED 13, and as a rectangular parallelepiped resin plate extending in the width direction of the concave portion 12A. It is glued to. Further, the entire surface of the partition wall 16 is subjected to the same plating treatment as that of the frame 12 so that visible light can be efficiently reflected.

  Therefore, most of the light emitted from the green light emitting unit 14 is reflected when it hits the partition wall 16, and does not enter the red light emitting unit 15. In addition, most of the light emitted from the red light emitting unit 15 is reflected when it hits the partition wall 16, and does not enter the green light emitting unit 14. However, in the vicinity of the upper portion of the partition wall 16, a very small gap is formed between the bottom surface of the recess 12 </ b> A and the lower end of the partition plate 16, and the green light-emitting portion 14, the red light-emitting portion 15, and a very small amount are formed in this gap. Light comes and goes.

  The light emitting device 11 of the present embodiment is configured as described above. Therefore, when blue light is emitted from the blue LED 13, a part thereof is used as excitation light by the green light emitting unit 14, and green light is emitted from the green light emitting unit 14. Further, another part of the blue light emitted from the blue LED 13 is used as excitation light by the red light emitting unit 15, and red light is emitted from the red light emitting unit 15. Further, a small amount of the green light emitted from the green light emitting unit 14 enters the red light emitting unit 15 through the upper portion of the partition wall 16 and is absorbed and used as excitation light. Then, the blue light, the green light, and the red light emitted in this way are each emitted from the light emitting surface 11A in a predetermined direction.

  With such a configuration, the light emitting device 11 can exhibit high luminous efficiency and color rendering. That is, since the partition wall 16 that prevents the light emitted from the green light emitting unit 14 from entering the red light emitting unit 15 is provided between the green light emitting unit 14 and the red light emitting unit 15. The amount of the light emitted by the light 14 is absorbed by the red light emitting unit 15 can be suppressed, and thereby the light emission efficiency and color rendering of the light emitting device 11 can be improved. In addition, since variation in light components emitted from the light emitting device 11 can be suppressed, the color reproducibility of the light emitting device 11 can be improved.

  Note that a part of the green light emitted from the green light emitting unit 14 through the upper portion of the partition wall 16 is incident on the red light emitting unit 15. However, since the amount thereof is extremely small, the light emission efficiency and the color rendering property are not reduced. No. Of course, if the partition wall 16 is provided so as to prevent the green light emitted from the green light emitting part 14 from entering the red light emitting part 15 at all, the light emission efficiency and the color rendering can be more reliably improved.

Further, since the surface of the frame 12 and the surface of the partition wall 16 can reflect all visible light, the blue light emitted from the blue LED 13, the green light emitted from the green light emitting unit 14, and the red light emitted from the red light emitting unit 15 are emitted. Since the emitted red light is emitted from the light exit surface 11A without being absorbed by the frame 12 or the partition wall 16, each light can be used effectively, and the luminous efficiency can be increased.
Moreover, according to the light-emitting device 11, the effect | action and effect similar to the light-emitting device 1 of 1st Embodiment can be show | played.

[I-4. Application of light emitting device]
There is no restriction | limiting in the use of the light-emitting device of this invention, It can apply to the arbitrary uses using light. Specific examples of applications include lighting, a backlight unit for display devices, and display devices (displays).

  There is no restriction | limiting in particular when using the light-emitting device of this invention as illumination, For example, it can use in various aspects as illumination, such as a flash for cameras, a light of a video camera, and an indoor and outdoor lighting fixture. Note that the light emitting device of the present invention has different wavelengths (that is, colors) of light emitted from the first light emitting unit and the second light emitting unit, but the light emitted from the light emitting device is emitted from the light emitting device. After that, it spreads sufficiently, and the light emitted from the light source, the first light emitting part, and the second light emitting part is visualized in a sufficiently mixed state, so the light is not separated into components when visually observed. Will be visualized as a color. If the light-emitting device of the present invention is used as illumination, light with high color rendering properties can be irradiated with high luminous efficiency.

  The light emitting device of the present invention can be used as a backlight unit by combining with an optical member such as a light guide plate. As a specific example, a display backlight unit is attached to a mobile phone display or the like in order to illuminate a liquid crystal display unit from the back. The light emitting device of the present invention is attached to the display backlight unit. Can be used.

  FIG. 3 is a diagram schematically showing a cross section of a main part of the display 21 of the mobile phone in order to explain an example of a backlight unit using the light emitting device of the present invention. As shown in FIG. 3, a light guide plate 23 having a size corresponding to the entire back surface of the liquid crystal display unit 22 is attached to the back surface of the liquid crystal display unit 22. The light guide plate 23 is formed as a flat optical member formed of a transparent material that transmits all light in the visible region, and a light emitting device 24 is attached to the side thereof. The light emitting device 24 is attached so that emitted light can enter the light guide plate 23, and the light guide plate 23 and the light emitting device 24 constitute a display backlight unit 25. Therefore, the light emitted from the light emitting device 24 enters the light guide plate 23 and is emitted from the surface of the light guide plate 23 facing the liquid crystal display unit 22 toward the liquid crystal display unit. As a result, the liquid crystal display unit 22 can be illuminated brightly. At this time, the wavelengths (namely, colors) of the light emitted from the first light emitting unit and the second light emitting unit of the light emitting device 24 are different, but the light emitted from the light emitting device 24 is mixed in the light guide plate 23. Since they are uniform, there is no risk of uneven color when the liquid crystal display unit 22 is illuminated.

  When the light emitting device of the present invention is used for a relatively large display device (display) or the like, the light emitting device of the present invention may be used as a backlight that directly illuminates the liquid crystal display unit from the back surface. Even in such a case, the light emitted from the light emitting device is mixed and made uniform before reaching the liquid crystal display unit, so that there is no possibility of uneven color.

In addition, in order to mix each component of the light emitted from the light emitting device, if the light emitted from the light emitting device is diffused using a diffusion plate, a light diffusing layer, etc., the light is more evenly distributed. Can do. Such a method is suitable for an application in which it is preferable not to leave even a slight unevenness in emission color, such as an indicator of an audio device.
As described above, when the light emitting device of the present invention is used as a backlight or a backlight unit of a display device, a display having good color reproducibility and high luminous efficiency (luminance) can be provided.

[II. Description of display device]
Next, the display device of the present invention will be described in detail with reference to a third embodiment of the present invention. However, although a third embodiment of the present invention will be described below with reference to the drawings, the present invention is not limited to the following third embodiment, and can be arbitrarily modified without departing from the gist of the present invention. Can be implemented.
4 to 6 are for explaining the third embodiment of the present invention, FIG. 4 is a schematic exploded perspective view for explaining the outline of the display device, and FIG. 5 is a schematic view of the backlight unit. FIG. 6 is a schematic cross-sectional view for explaining the main part of the backlight unit.

The display device of this embodiment includes a backlight unit and an image forming unit. In addition, the display device of this embodiment is configured to include other components such as a diffusion plate and a light guide plate as appropriate.
FIG. 4 is a schematic exploded perspective view showing the display device of the present embodiment. As shown in FIG. 4, the display device of this embodiment includes a backlight unit 101, a diffusion plate 102, and an image forming unit 103.

[II-1. Backlight unit]
The backlight unit 101 is a member that emits white light as a backlight toward the image forming unit 103 via the diffusion plate 102. Here, the backlight unit 101 emits white light not only when the light immediately after being emitted from the backlight unit 101 is white, but also immediately after being emitted from the backlight unit 101. The case where light that is not diffused and does not become white is diffused before reaching the image forming unit 103 and becomes white when it reaches the image forming unit 103 is also widely referred to.

  FIG. 5 is a schematic plan view of the backlight unit 101 used in the display device of this embodiment. As shown in FIG. 5, in this embodiment, the backlight unit 101 has a plurality of (here, seven) light emitting portions 105 for emitting white light on a substrate 104 as a frame. . Each light emitting unit 105 includes a green light emitting unit 106 as a first light emitting unit and a red light emitting unit 107 as a second light emitting unit.

[II-1-1. substrate]
The substrate 104 is a base for providing the light emitting unit 105, and can be configured similarly to the frame in the above-described light emitting device. Therefore, the shape, dimensions, etc. can be arbitrarily set according to the shape, dimensions, application, etc. of the display device. For example, examples of the shape of the light emitting unit 105 of the substrate 104 include a plate shape and a cup shape. Also, it is desirable that the surface has an appropriate shape such as a flat surface, a curved surface, and an uneven surface depending on the application.

  Further, although the material of the substrate 104 is also arbitrary, it is usually preferable to form it with a material that does not transmit at least green light. Although it is possible to use a material that transmits green light as the material of the substrate 104, in that case, a process that prevents the transmission of green light, such as coating the surface of the substrate 104 with a material that does not transmit green light at least. Is preferably performed. The point of preventing the transmission of green light will be described in detail in the description of the light emitting unit 105.

  A specific example of the substrate 104 is the same as the frame in the light-emitting device described above. Among these, ceramics is preferable as the inorganic material, and glass epoxy resin is preferable as the organic material. In addition, the material of the board | substrate 104 may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

In addition, it is preferable to use a material with good heat dissipation as the material of the substrate 104. For example, it is preferable to use a material having high thermal conductivity. The light source in the light emitting unit 105 (see the blue light source 108 in FIG. 6) emits heat during use, but if the substrate 104 is formed with a good heat dissipation property, it is stable even if heat is generated during use. This is because the use can be continued.
Further, it is preferable to use an insulating material for the substrate 104.

  However, in the case of configuring a display device, it is preferable to pay attention to the color when selecting the material of the substrate 104. Although the color of the substrate 104 is arbitrary, it is usually preferable to use a white or silver material. This is due to the following reason. That is, a part of white light emitted from the light emitting unit 105 is reflected by the diffuser plate 102 and the image forming unit 103 or light incident from outside the display device is directed toward the image forming device 103 of the backlight unit 101. In some cases, the light is reflected by a surface that emits white light (hereinafter, referred to as “white light emitting surface” as appropriate), and the reflected light illuminates the image forming unit 103 from the back. At this time, if the substrate 104 absorbs visible light, there is a possibility that the light emission efficiency may be reduced or the color shift may occur. Therefore, it is preferable that at least a portion to be the white light emitting surface of the substrate 104 is white or silver. Therefore, the white light emission surface of the substrate 104 is preferably formed of a white or silver material.

  Further, a portion of the surface of the substrate 104 facing the green light emitting portion 106 and the red light emitting portion 107 in the light emitting portion 105 can increase the reflectance of at least one of the components of the light hitting that portion. In particular, it is more preferable that the reflectance of light in the entire visible light range is increased. Thereby, the luminous efficiency of the backlight unit 101 can be further increased. Therefore, it is preferable that the portion where the light hits is formed of a material having high reflectance. As an example of a method for increasing the reflectance, for example, a method similar to that of the above-described light emitting device can be given.

  In general, the substrate 104 is provided with electrodes and wirings for supplying power to the light source. The electrodes and wirings may be formed in any way. However, in the case of forming a display device, it is preferable that a wiring pattern is formed on the back surface of the substrate 104 using a through hole, which is easy to manufacture. The material of the electrode and wiring is also arbitrary, and for example, Cu, Cu plated with Au, Cu plated with Ag, Al, Ag, or the like can be used.

  In this embodiment, the substrate 104 is formed as a white plate-like substrate 104, and the surface of the green light emitting unit 106 and the red light emitting unit 107 is subjected to a surface treatment so that light having a wavelength in the entire visible range can be reflected. Suppose that Further, the substrate 104 is provided with wiring 109 for supplying power to the blue light source 108 on the back surface, and further includes electrodes 110 at positions corresponding to the respective light emitting portions 105 (see FIG. 6).

[II-1-2. Blue light source]
FIG. 6 is a schematic cross-sectional view of the light emitting unit 105. As shown in FIG. 6, the light emitting unit 105 includes a green light emitting unit 106 that is a first light emitting unit and a red light emitting unit 107 that is a second light emitting unit. Further, a blue light source 108 is provided in each of the green light emitting unit 106 and the red light emitting unit 107.

  The blue light source 108 is a light source that emits blue light in order to emit excitation light of the luminescent material contained in the green light emitting unit 106 and the red light emitting unit 107, similarly to the light source in the light emitting device described above, and a backlight. It is also a light source for emitting blue light as one component of white light emitted by the unit 101. That is, part of the blue light emitted from the blue light source 108 is absorbed as excitation light by the luminescent substances in the green light emitting unit 106 and the red light emitting unit 107, and another part is imaged from the backlight unit 101. It is discharged toward the forming unit 103.

The type of the blue light source 108 is arbitrary, and an appropriate one can be selected according to the use and configuration of the display device. However, in general, the light source is not biased and the emitted light is widely diffused. Is preferred.
Examples of the blue light source 108 include the same ones as exemplified in the description of the light emitting device, but an inexpensive LED is usually preferable.

Further, when an LED is used as the blue light source 108 as described above, the shape thereof is not limited and is arbitrary. However, in order to improve the light extraction efficiency, the side surface is preferably tapered.
Furthermore, the material of the LED package is arbitrary, and for example, ceramics, PPA (polyphthalamide), or the like can be used as appropriate. However, like the substrate 104 described above, the color of the package is preferably white or silver from the viewpoint of improving the color reproducibility of the display device, and from the viewpoint of increasing the light emission efficiency of the backlight unit 101, the reflectance of light. Is preferably increased. If there is a wiring for the blue light source 108, the color and reflectance of the wiring are the same as those of the substrate 104 and the LED package.

  Moreover, when attaching the blue light source 108 to the board | substrate 104, the specific method is arbitrary, For example, it can attach using solder | pewter. Although the kind of solder is arbitrary, the thing similar to what was illustrated by description of the light-emitting device is mentioned, for example. In particular, when a large current type LED or laser diode, for which heat dissipation is important, is used as the blue light source 108, it is effective to use the solder for installing the blue light source 108 because the solder exhibits excellent heat dissipation. .

  Moreover, when attaching the blue light source 108 to the board | substrate 104 by means other than solder, the thing similar to what was illustrated by description of the light-emitting device is mentioned, for example. In this case, by using a paste in which conductive fillers such as silver particles and carbon particles are mixed into the adhesive, the adhesive is energized to supply power to the blue light source 108 as in the case of using solder. It is also possible to make it possible. Furthermore, it is preferable to mix these conductive fillers because heat dissipation is improved.

  Furthermore, the method of supplying power to the blue light source 108 is also arbitrary, and examples thereof include the same ones as exemplified in the description of the light emitting device.

One blue light source 108 may be used alone, or two or more light sources may be used in combination. Further, the blue light source 108 may be used alone or in combination of two or more.
The blue light source 108 may share one blue light source 108 between the green light emitting unit 106 and the red light emitting unit 107 or between two or more light emitting units 105. In order to improve the color rendering property of white light emitted from 101, it is preferable to provide a blue light source 108 in each of the green light emitting unit 106 and the red light emitting unit 107.

  Further, the wavelength of blue light emitted from the blue light source 108 is arbitrary as long as the backlight unit 101 can emit light having a desired wavelength (in this embodiment, white light), but is usually 350 nm or more, preferably 370 nm or more, more preferably 380 nm or more, more preferably 400 nm or more, particularly preferably 430 nm or more, and usually 600 nm or less, preferably 570 nm or less, more preferably 550 nm or less, further preferably 500 nm or less, particularly preferably 480 nm or less. Those that absorb light are desirable.

Among them, the wavelength of blue light emitted from the blue light source 108 used for the green light emitting unit 106 is usually 350 nm or more, preferably 400 nm or more, more preferably 430 nm or more, and usually 520 nm or less, preferably 500 nm or less, more preferably 480 nm or less. Is desirable.
On the other hand, the wavelength of blue light emitted from the blue light source 108 used for the red light emitting unit 107 is usually 400 nm or more, preferably 450 nm or more, more preferably 500 nm or more, and usually 600 nm or less, preferably 570 nm or less, more preferably 550 nm or less. It is desirable to absorb the light.

  In the present embodiment, as the blue light source 108, it is assumed that LEDs emitting blue light are used for the green light emitting unit 106 and the red light emitting unit 107, respectively. Further, as shown in FIG. 6, the substrate 104 includes a wiring 109 formed on the back surface thereof, each blue light source 108 and an electrode 110 connecting the wiring 109, and the blue light source 108 is formed by the wiring 109 and the electrode 110. It is assumed that power can be supplied to

[II-1-3. Green light emitting part and red light emitting part]
The green light emitting unit 106 as the first light emitting unit is excited by blue light emitted from the blue light source 108 and emits green light including a component of a green light emitting region having a longer wavelength than the blue light. (Green illuminant) is included.
In general, the green light emitting unit 106 is formed as a filling unit (concave portion) formed in the substrate 104 filled with the above-described luminescent material. Therefore, the green light emitting portion 106 is formed in a shape corresponding to the shape of the filling portion. Although there is no particular limitation on the shape of the green light emitting unit 106, normally, for example, if the cup is formed as shown in FIG. Since it can raise, it is preferable.

Further, the green light emitting units 106 can be provided alone at one place or divided into two or more places. Further, the same number of green light emitting units 107 may be provided with respect to the number of red light emitting units 107, or only different numbers. It may be provided.
The green light emitting unit 106 receives blue light emitted from the blue light source 108, and thereby the luminescent material emits light using the received blue light as excitation light. The emitted light (green light) is emitted toward the image forming unit 103 as a component of white light emitted from the backlight unit 101.

On the other hand, the red light emitting unit 107, which is the second light emitting unit, can be excited by the blue light emitted from the blue light source 108 to emit red light including components of the red light emitting region having a longer wavelength than the blue light and the green light. It is formed including at least one kind of luminescent material (red luminescent material).
Usually, like the green light emitting unit 106, the red light emitting unit 107 is formed as a filling portion (concave portion) formed on the substrate 104 filled with the above-described light emitting substance. Therefore, the shape of the red light emitting portion 107 is also formed in a shape according to the shape of the filling portion. The shape of the red light emitting unit 107 is not particularly limited, but it is usually preferable that the red light emitting unit 107 has a cup shape like the green light emitting unit 106.

Further, the red light emitting units 107 can be provided alone at one place or divided into two or more places, and the same number as the number of green light emitting units 106 may be provided, or different numbers. You may provide only.
The red light emitting unit 107 receives the blue light emitted from the blue light source 108, and the light emitting material emits light using the received blue light as excitation light. The emitted light (red light) is emitted toward the image forming unit 103 as a component of white light emitted from the backlight unit 101.

  However, in the present embodiment, the green light emitting unit 106 and the red light emitting unit 107 are each formed at least partially, preferably all independently. That is, by forming the green light emitting unit 106 and the red light emitting unit 107 separately, at least a part, preferably all, of the green light emitted from the green light emitting unit 106 does not enter the red light emitting unit 107. To form. Usually, the green light emitted from the green light emitting unit 106 is high enough that the white light emitted from the backlight unit 101 toward the image forming unit 103 can exhibit practically high light emission efficiency and color reproducibility. Can be prevented from entering the red light emitting portion 107. Further, it is preferable that all green light emitted from the green light emitting unit 106 does not enter the red light emitting unit 107. As a result, it is possible to prevent the green light emitted from the green light emitting unit 106 from being consumed as the excitation light of the luminescent material by the red light emitting unit 107, and thus suppress the decrease in the intensity of the green light emitted from the green light emitting unit 106. Thus, the light emission efficiency of the backlight unit 101 can be increased. Further, since the green light is absorbed as the excitation light, the intensity of the red light emitted from the red light emitting unit 107 can be prevented from being excessively increased, so that the color rendering property of the white light emitted from the backlight unit 101 is improved. There is also an advantage of being able to.

  Since the green light emitting unit 106 and the red light emitting unit 107 are usually formed by filling each light emitting material in a filling unit formed on the substrate 104, the green light emitted from the green light emitting unit 106 by the substrate 104 is blocked. Thus, it is prevented from entering the red light emitting unit 107. That is, the portion between the green light emitting portion 106 and the red light emitting portion 107 of the substrate 104 functions as the light shielding portion described above in the description of the light emitting device. Of course, for this purpose, as described above, the material of the substrate 104 is at least a material capable of blocking green light, or the surface is coated.

  In particular, the above-described blue light, green light can be obtained by forming not only simply preventing the transmission of green light but also reflecting at least one, preferably all, of blue light, green light, and red light. Further, red light or the like can be used effectively, and the light emission efficiency of the backlight unit 101 can be further improved.

  In order to more reliably prevent the transmission of green light, a wall portion that prevents the transmission of green light may be provided between the green light emitting unit 106 and the red light emitting unit 107. For example, if a portion between the green light emitting portion 106 and the red light emitting portion 107 on the white light emitting surface of the substrate 104 is formed to be convex, the convex portion is used as the wall portion to more reliably prevent the transmission of green light. be able to. At this time, the shape and dimensions of the wall portion are arbitrary. Further, the material of the wall portion is also arbitrary, and the same material as that of the substrate 104 can be used. Further, as with the substrate 104, it is preferable to increase the reflectance of the wall surface. In this case, this wall portion also functions as the above-described light shielding portion.

  Furthermore, as described above, in order to prevent the green light emitted from the green light emitting unit 106 from entering the red light emitting unit 107, both the green light emitting unit 106 and the red light emitting unit 107 are externally exposed on the white light emitting surface. It is desirable to be open. That is, the green light emitted from the green light emitting unit 106 is emitted from the white light emitting surface toward the image forming unit 103 without passing through the red light emitting unit 107, and the red light emitted from the red light emitting unit 107 is green. It is desirable that light is emitted from the white light emitting surface toward the image forming unit 103 without passing through the light emitting unit 106. In addition, a protective layer is formed on the white light emission surface, or a cover is attached to the backlight unit 101, and green light and red light pass through other members such as the protective layer and the cover, and the backlight unit 101 Even when the light is emitted to the outside, the green light emitting unit 106 and the red light emitting unit 107 are open as long as the green light and the red light can pass through other members such as a protective layer and a cover.

  When the green light emitting unit 106 and the red light emitting unit 107 are opened at the white light emitting surface as described above, the green light and the red light are absorbed by other light emitting materials or shielded by other members, respectively. The degree of weakening can be reduced (or eliminated). Therefore, the light emission efficiency of the backlight unit 101 can be increased. Furthermore, variation in white light components emitted from the backlight unit 101 can be reduced, and color rendering can be improved. In addition, since it is possible to reliably emit white light using the three primary colors of blue light, green light, and red light, by appropriately selecting the blue light source 108, the green light emitting unit 106, and the red light emitting unit 107, The color reproducibility of the display device can also be improved.

The mechanism that can increase the light emission efficiency of the backlight unit 101 is basically the same as that of the light emitting device, but paying attention to the use as a display device in particular, in contrast to the conventional technology, Again, the mechanism by which the light emission efficiency of the backlight unit 101 can be increased will be described in detail.
Conventionally, when white light is synthesized without simultaneously using all of blue light, green light, and red light, color reproducibility has not been sufficient. Further, even when all of blue light, green light, and red light are used at the same time, the light emitting part 105 is not divided into the green light emitting part 106 and the red light emitting part 107, and the light emitting material that emits green light and the light emission that emits red light. When white light was synthesized using a substance, part of the green light was absorbed and consumed by the luminescent substance emitting red. This is because, even when a light emitting material that emits green light and a light emitting material that emits red light are mixed and dispersed in the same light emitting portion, the light emitting material that emits green light and red light are emitted as in Patent Document 1. The same was true when the light-emitting substance was used separately in another light-emitting portion. For this reason, the intensity of the green light that should have been emitted outside the backlight unit 101 is reduced, the luminous flux of white light emitted from the backlight unit 101 is reduced, and the light emission efficiency is reduced. Furthermore, the green light is absorbed by the light emitting substance that emits red light, and the red light becomes stronger, so that the balance of the components of the white light emitted from the backlight unit 101 varies, which reduces the color reproducibility of the display device. It was.

  When white light emitted from the backlight unit 101 is intended to be a target white, conventionally, in order to supplement the light from the green light emitting part absorbed by the red light emitting part, the light emitting material that emits red light is used. Therefore, it is necessary to increase the ratio of the luminescent material in the green light emitting part. However, since the color rendering properties of white light are determined by the type and usage ratio of the luminescent material to be used, in conventional backlight units such as Patent Document 1, the usage ratio of the luminescent material is likely to deviate significantly from the optimum value. The color rendering properties also tended to decrease.

On the other hand, in the backlight unit 101 as used in the present embodiment, green light can be prevented from entering the red light emitting unit 107, so that the green light is absorbed by the red light emitting unit 107 and its intensity is weak. It can be suppressed. Therefore, the light emission efficiency of the backlight unit 101 can be improved as compared with the conventional case.
Further, since it is possible to suppress the red light emitting unit 107 from absorbing green light and emitting light, the variation in the white light component emitted from the backlight unit 101 is reduced and the color rendering properties of the backlight unit 101 are reduced. Can also be increased. As a result, the color rendering properties and color reproducibility of the display device can be improved.

  By the way, if the light (blue light, green light, and red light) emitted from the blue light source 108, the green light emitting unit 106, and the red light emitting unit 107 can be emitted from the backlight unit 101, the green light emitting unit 106 and the red light emitting unit 107. However, the green light emitting unit 106 and the red light emitting unit 107 can be combined so that the desired white light can be emitted and installed as the light emitting unit 105 as in this embodiment. preferable. That is, since the color of the white light is determined according to the color and the intensity ratio of the blue light, the green light, and the red light, the green light emitting unit 106 that emits the white light of the target color and the red light. If the light emitting unit 105 is configured as a unit unit by combining the light emitting units 107 as small as possible, and if the intensity of white light is to be increased, the design is performed by increasing the number of light emitting units 105 as unit units. And is preferred because it simplifies manufacturing. In the present embodiment, one green light emitting unit 106 and one red light emitting unit 107 are provided in one light emitting unit 105, but the number is arbitrary, and two or more may be provided as appropriate. .

Further, the arrangement of the green light emitting unit 106 and the red light emitting unit 107 in the light emitting unit 105 is arbitrary, and may be arranged side by side as in the present embodiment, or one may surround the other. Further, it may be arranged in a more complicated shape.
Furthermore, when increasing the number of the light emission parts 105, arrangement | positioning of each light emission part 105 is also arbitrary. However, since the image forming unit 103 can be illuminated uniformly when the distances between the light emitting portions 105 are made uniform, as shown in FIG. 5, each light emitting portion 105 is represented by a figure in which equilateral triangles are continuous (see the broken line in FIG. 5). It is preferable to arrange so that it is located at the apex of each triangle.

  In addition, the dimensions of the green light emitting unit 106 and the red light emitting unit 107 are arbitrary, but are usually set according to the target white light. As described above, the white light is emitted from the backlight unit 101 to the image forming unit 103 as light obtained by combining the blue light, the green light, and the red light. Therefore, the apparent color of white light also changes according to the intensity of each of blue light, green light and red light to be combined. For this reason, in order to create white light of the target color, the balance of the intensity of each of blue light, green light and red light is adjusted. At this time, as one method for adjusting the balance of the intensity of each of blue light, green light, and red light, there is a method of adjusting the dimensions of the green light emitting unit 106 and the red light emitting unit 107. That is, when the green light 106 is to be increased, the green light emitting unit 106 is relatively large with respect to the red light emitting unit 107, and when the green light 106 is desired to be weakened, the green light emitting unit 106 is relatively decreased with respect to the red light emitting unit 107. It ’s fine.

Furthermore, the method for adjusting the balance of the intensity of each of blue light, green light, and red light is not limited to the method for adjusting the dimensions of the green light emitting unit 106 and the red light emitting unit 107 described above. Can be adopted.
For example, the ratio of the current value of the power supplied to the blue light source 108 provided in the green light emitting unit 106 and the current value of the power supplied to the blue light source 108 provided in the red light emitting unit 107 is adjusted to thereby adjust the blue color. The target white light may be emitted by adjusting the intensity balance of light, green light, and red light.

Further, for example, the blue light source 108 may be pulse-driven and adjusted according to its duty ratio. That is, the ratio between the pulse lighting time of the blue light source 108 provided in the green light emitting unit 106 and the pulse lighting time of the blue light source 108 provided in the red light emitting unit 107 is adjusted, thereby blue light, green light, and red light. The target white light may be emitted by adjusting the balance of the intensity of each light.
Furthermore, the ratio of the amount of the luminescent material contained in each of the green light emitting unit 106 and the red light emitting unit 107 is adjusted to adjust the balance of the intensity of each of the blue light, the green light, and the red light. Light may be emitted.

  By the way, when adjusting the balance of the color and intensity of blue light, green light, and red light so that the target white light can be emitted as described above, it is actually emitted from the green light emitting unit 106. And the light emitted from the red light emitting unit 107 are adjusted. That is, white light that is formed by combining blue light, green light, and red light, for example, combines light that combines blue light and green light (hereinafter referred to as “short wavelength light” as appropriate) with blue light and red light. In this case, the short wavelength light is emitted from the green light emitting part, and the long wavelength light is emitted from the red light emitting part. It is the light emitted from. Therefore, in order to adjust the color of the white light emitted from each light emitting unit 105, the green light emitting unit 106 and the red light emitting unit 107 are controlled, and the short light emitted from each of the green light emitting unit 106 and the red light emitting unit 107 is controlled. What is necessary is just to adjust the color and intensity | strength of wavelength light and long wavelength light.

At this time, the short wavelength light (that is, light obtained by combining blue light and green light) has a normal chromaticity coordinate (x, y) (0.25, 0.65) as shown in FIG. ), (0.43, 0.52), (0.32, 0.33), and (0.18, 0.33) (in the region I in FIG. 7), preferably (0. 27, 0.53), (0.34, 0.49), (0.27, 0.34), and (0.22, 0.35). It is desirable to do so. This is because the balance between luminance and color reproducibility is improved.
Further, the long wavelength light (light obtained by combining blue light and red light) has an opposite coordinate with respect to the chromaticity coordinate of the target white light with respect to the chromaticity coordinate of the short wavelength light. What is necessary is just to determine the chromaticity coordinate.

  In the present embodiment, the light emitting unit 105 is formed by filling the green light emitting unit 106 and the red light emitting unit on the surface of the substrate 104 in the same shape (the upper surface is circular and the cross section is trapezoidal) one by one. It is assumed that the portion 107 is formed by filling a light emitting material and a binder respectively corresponding to the portion 107. Further, as shown in FIG. 6, each light emitting unit 105 is arranged such that each light emitting unit 105 is positioned at the apex of each triangle of a figure (see the broken line in FIG. 6) in which equilateral triangles are continuous. It is assumed that the distances between the light emitting units 105 are arranged to be equal.

[II-1-4. Composition of light emitting part]
The green light emitting unit 106 as the first light emitting unit includes a light emitting material that absorbs excitation light and emits green light. The red light emitting unit 107 as the second light emitting unit includes a light emitting material that absorbs excitation light and emits red light. Further, in the green light emitting unit 106 and the red light emitting unit 107, each light emitting substance is normally held on the substrate 104 by a binder.

[II-1-4-1. Luminescent substance]
As the light-emitting substance, known substances can be appropriately selected and used. The light emission itself is not limited by any mechanism such as fluorescence or phosphorescence. Moreover, in each of the green light emission part 106 and the red light emission part 107, a light emitting substance may be used individually by 1 type, and 2 or more types can be used together by arbitrary combinations and a ratio. However, it is preferable to select an appropriate luminescent substance for each of the green light emitting unit 106 and the red light emitting unit 107 in accordance with the chromaticity coordinates of the target white light.

  The wavelength of the green light emitted by the light emitting material that absorbs the excitation light and emits green light used for the green light emitting unit 106 is arbitrary as long as the backlight unit 101 can emit white light. A wavelength range similar to the preferable emission wavelength range of the luminescent material used in the first light emitting unit mentioned in the description of the light emitting device can be given.

  On the other hand, the wavelength of red light emitted from the luminescent material that absorbs excitation light and emits red light used in the red light emitting unit 107 is arbitrary as long as the backlight unit 101 can emit white light, but preferably A wavelength range similar to the preferable emission wavelength range of the luminescent material used for the second light emitting unit mentioned in the description of the light emitting device can be given.

  Further, it is preferable to use a luminescent substance having a luminous efficiency of usually 40% or more, preferably 45% or more, more preferably 50% or more, still more preferably 55% or more, and most preferably 60% or more. . The luminous efficiency shown here is a value expressed as a product of quantum absorption efficiency and internal quantum efficiency.

  As examples of preferable luminescent materials, examples of the luminescent materials of the green light emitting unit 106 include the same materials as those described as examples of the luminescent materials suitable for the first light emitting unit in the description of the light emitting device. On the other hand, examples of the light-emitting substance of the red light-emitting portion 107 include the same materials as those described as examples of the light-emitting substance suitable for the second light-emitting portion in the description of the light-emitting device.

  Further, in the case of constituting a display device, the luminescent substance is usually used in the form of particles, both those emitting green light and those emitting red light. At this time, the particle diameter of the luminescent material particles is arbitrary, but is usually 150 μm or less, preferably 50 μm or less, more preferably 20 μm or less, and further preferably 15 μm or less. Above this range, the variation in the color of the white light emitted from the backlight unit 101 becomes large, and it is difficult to uniformly apply the luminescent material when the luminescent material and the sealing material (binder) are mixed. There is a risk of becoming. Moreover, it is 0.001 micrometer or more normally, Preferably it is 0.01 micrometer or more, More preferably, it is 0.1 micrometer or more, More preferably, it is 1 micrometer or more, Especially preferably, it is 2 micrometers or more, Most preferably, it is 5 micrometers or more. Below this range, the luminous efficiency may be reduced.

In addition, when forming the green light emission part 106 and the red light emission part 107 without using a binder, it can form similarly to the 1st light emission part and the 2nd light emission part in the light-emitting device mentioned above, for example.
Further, the red light emitting unit 107 may be mixed with a light emitting material that emits green light in addition to a light emitting material that emits red light, a binder, and other components. However, in order to obtain a larger luminous flux, the concentration of the luminescent material that emits green light included in the red light emitting unit 107 is preferably small, and the red light emitting unit 107 does not include a luminescent material that emits green light. More preferred.

  On the other hand, the green light emitting unit 106 does not normally contain a light emitting substance that emits red light, but may contain a light emitting substance that emits red light as long as the luminous flux of the green light is not reduced. In that case, the ratio of the luminescent material that emits red light contained in the green light emitting unit 106 is generally desirably 40% by volume or less, and more desirably, the green light emitting unit 106 does not contain any luminescent material that emits red light.

  That is, even if the light emitting material emitting red light is excited by the green light, the light emitting material emitting red light absorbs the green light emitted from the light emitting material of the green light emitting unit 106 in the green light emitting unit 106. The luminescent materials in the green light emitting part 106 and the red light emitting part 107 should be adjusted so that they are not too much.

[II-1-4-2. Binder]
As described above, the green light emitting unit 106 and the red light emitting unit 107 may contain a binder in addition to the light emitting material. As in the case of the light-emitting device described above, the binder is usually used to collect powdery or particulate light-emitting substances or attach them to the substrate 104. There is no restriction | limiting about the binder used for the backlight unit 101, A well-known thing can be used arbitrarily.

  However, the backlight unit 101 is of a transmissive type, that is, as shown in FIG. 6, light emitted from the blue light source 108, the green light emitting unit 106, and the red light emitting unit 107 is transmitted through the green light emitting unit 106 or the red light emitting unit 107. Then, when configured to be emitted to the outside of the backlight unit 101, the binder transmits the white light components emitted from the backlight unit 101 (that is, blue light, green light, and red light). It is desirable to select.

When the example of a binder is given, the thing similar to the light-emitting device mentioned above is mentioned.
Further, when a resin is used as the binder, the viscosity of the resin is arbitrary, but it is desirable to use a binder having an appropriate viscosity according to the particle size and specific gravity of the luminescent material to be used, in particular, the specific gravity per surface area. . For example, as in the case of the light-emitting device described above, when the epoxy resin is used for the binder, if the particle diameter of the light-emitting substance particles is 2 μm to 5 μm and the specific gravity is 2 to 5, it is usually 1 to 10 Pas. It is preferable to use an epoxy resin having a viscosity because the phosphor particles can be well dispersed.
In addition, a binder may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

[II-1-3-3. Usage ratio of luminescent materials]
When a binder is used for the green light emitting unit 106 and the red light emitting unit 107, the ratio of the light emitting substance to the binder is not limited, but the ratio of the light emitting substance to the binder is usually 0.01 or more, preferably 0. It is desirable that it is 05 or more, more preferably 0.1 or more, and usually 5 or less, preferably 1 or less, more preferably 0.5 or less.

  However, when the backlight unit 101 is a transmissive type, it is desirable that the luminescent material is appropriately dispersed in the green light emitting unit 106 and the red light emitting unit 107 in order to obtain a higher luminous flux. On the other hand, the backlight unit 101 is of a reflective type (that is, the light emitted from the blue light source 108, the green light emitting unit 106, and the red light emitting unit 107 does not pass through the green light emitting unit 106 or the red light emitting unit 107 and In order to obtain a higher luminous flux, it is preferable that the luminescent material is filled at a high density. Therefore, the composition of the luminescent material should be set in accordance with the use of the display device, the type and physical properties of the luminescent material, the type and viscosity of the binder, etc., taking these into consideration.

  Note that the emission color of white light emitted from the backlight unit 101 is not only normal white light with chromaticity coordinates (x, y) of (0.33, 0.33), but also a liquid crystal plate or display plate to be combined, diffusion For example, color coordinates (x, y) can be (0.28, 0.25), (0.25, 0.28), (0.34, 0.40) and (0.40, 0.34) are also possible for the emission color to be within the region.

[II-1-4-4. Other ingredients]
Alternatively, the light emitting material may contain other components, and the green light emitting unit 106 and the red light emitting unit 107 may be formed using the light emitting material, and a binder and other components used as appropriate.
There is no restriction | limiting in particular in another component, A well-known additive can be used arbitrarily. For example, the same light emitting device as that described above can be used.

[II-1-4-5. Method for manufacturing light emitting part]
There is no particular limitation on a method for manufacturing the green light emitting portion 106 and the red light emitting portion 107, and the green light emitting portion 106 and the red light emitting portion 107 can be manufactured by any method. For example, it can be manufactured in the same manner as the first light-emitting portion and the second light-emitting portion in the light-emitting device described above.

  In the present embodiment, it is assumed that each of the green light emitting unit 106 and the red light emitting unit 107 is formed of a corresponding phosphor and binder. Further, if appropriate blue light is emitted from the blue light source 108, when the light emitted from the backlight unit 101 is diffused by the diffusion plate 102, white light {that is, chromaticity coordinates (x = 0) is obtained. .33, y = 0.33)}, the amount and type of each light-emitting substance, and the dimensions of the green light-emitting portion 106 and the red light-emitting portion 107 are set. .

[II-2. Diffusion plate]
The diffuser plate 102 is a member that diffuses light emitted from the backlight unit 101. As shown in FIG. 4, the diffuser plate 102 is provided between the backlight unit 101 and the image forming unit 103, and the light emitted from the backlight unit 101 is diffused inside the diffuser plate 102 to generate white light. Light is emitted to the image forming unit 103.

There is no restriction | limiting in the specific structure of the diffusion plate 102, A shape, material, a dimension, etc. are arbitrary. A known diffusion plate can be used as appropriate. For example, a sheet having irregularities on the front and back is used. In addition, for example, a structure in which fine particles such as synthetic resin and glass are dispersed in a binder such as a synthetic resin can be used. In this case, light diffusion is caused by a difference in refractive index between the binder and the fine particles. It has become. The sheet, binder, fine particles, and the like used in this case are usually formed of a material that can transmit each component of white light emitted from the backlight unit 101, that is, blue light, green light, and red light. Is done.
In the present embodiment, it is assumed that a sheet transparent to visible light having irregularities formed on the front and back surfaces is used as the diffusion plate 102.

[II-3. Image forming unit]
The image forming unit 103 is a member that irradiates the white light emitted from the backlight unit 101 on the back side and forms an image on the front side. There is no particular limitation as long as it can form an image and transmit at least part of the irradiated backlight, and a known member having any shape, size, material, or the like can be used.

Specific examples of the image forming unit 103 include a liquid crystal unit used for a liquid crystal display, a sign used for an internal illumination sign, and the like.
For example, as an example of a liquid crystal unit, a color filter, transparent electrode, alignment film, liquid crystal, alignment film, and a liquid crystal layer in which the transparent electrode overlaps in the above order are held in a container such as a glass cell with a polarizing film attached to the front and back The thing of the made structure is mentioned. In this case, in the liquid crystal unit, an image is formed by controlling the molecular arrangement of the liquid crystal by an electrode applied to the transparent electrode. At this time, the backlight unit 101 described above is white light (backlight) from the back side. By illuminating the liquid crystal unit, the image formed on the liquid crystal unit can be clearly displayed on the surface side of the liquid crystal unit.

  Further, the position where the display device displays the image formed on the image forming unit may be on the surface side of the image forming unit. In addition to displaying the image directly on the surface side of the image forming unit, the image is displayed on some projection surface. You may make it project and display. As an example of such a thing, a liquid crystal projector etc. are mentioned, for example.

For example, when a sign is used as the image forming unit, the backlight unit 101 described above illuminates the sign with white light (backlight) from the back, so that the image formed on the sign is clearly displayed on the surface side of the sign. Can be displayed.
The image formed on the image forming unit 103 is arbitrary, and may be a character or an image.
In this embodiment, a liquid crystal unit that directly displays an image on the surface is used as the image forming unit 103.

[II-4. effect]
Since the display device of the present embodiment has the above-described configuration, the wiring 109 and the electrodes are arranged so that the blue light source 108 of the backlight unit 101 can emit the target white light when used. Appropriate power is supplied via 110. The blue light source 8 to which power is supplied emits blue light having an intensity corresponding to the supplied power, part of which is emitted to the diffuser plate 102 as one component of white light, and the other part emits corresponding green light. It is absorbed by the luminescent material in the portion 106 or the red light emitting portion 107.

  The green light emitting unit 106 is excited by blue light absorbed by the luminescent material to emit green light, and the green light is emitted to the diffusion plate 102 as a component of white light. The red light emitting unit 107 emits red light when excited by the red light absorbed by the luminescent material, and the red light is also emitted to the diffusion plate 102 as a component of white light. At this time, since the green light emitting unit 106 and the red light emitting unit 107 are provided independently from each other, the green light is not absorbed by the light emitting material in the red light emitting unit 107, and thus the luminous flux of the green light is reduced. And the balance of white light components is not disturbed.

  Blue light, green light, and red light emitted from the backlight unit 101 enter the diffusion plate 102, are diffused by the diffusion plate 102, and are emitted to the image forming unit 103. Since the light emitted from the backlight unit 101 is diffused by the diffusion plate 102 even when it is in a state of being viewed as a discrete color without being sufficiently diffused before entering the diffusion plate 102, When it is emitted to the image forming unit 103, it becomes a good white light that is visually recognized as white.

The image forming unit 103 irradiates the back surface with white light emitted from the diffusion plate 102. As a result, the image formed on the image forming unit 103 is clearly projected on the surface of the image forming unit 103. At this time, white light contains blue, green, and red light as components, and the balance of the components of white light is kept good, so that color reproduction when an image formed on the image forming unit 103 is projected is performed. The properties are very good.
Further, since the green light is prevented from being absorbed by the light emitting substance in the red light emitting unit 107, it is possible to suppress the decrease in the luminous flux, thereby reducing the energy for generating the backlight. That is, the light emission efficiency of the backlight can be increased.

[II-5. Others]
As described above in detail, the display device of the present invention is not limited to the above-described third embodiment, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
For example, the green light emitting unit 106 or the red light emitting unit 107 may be formed in a reflective type as shown in FIG. That is, in the configuration of FIG. 8, the blue light source 108 is provided away from the substrate 104 by the beam 111, and the green light emitting portion 106 and the red light emitting portion 107 are formed by coating on the concave surface of the substrate 4. The wiring 109 and the electrode 110 are provided on the surface of the substrate 104 and the beam 111 so that power can be supplied to the blue electrode 108. In other respects, the green light emitting unit 106 and the red light emitting unit 107 in FIG. 8 are configured in the same manner as in the third embodiment. In this case, part of the blue light emitted from the blue light source 108 is emitted toward the image forming unit 103 as one component of white light, and the other part is emitted toward the green light emitting unit 106 and the red light emitting unit 107. It is done. The green light emitting unit 106 and the red light emitting unit 107 formed on the concave surface are excited by blue light to emit green light and red light, so that the backlight unit 101 can emit white light. It has become. Further, since the green light emitting unit 106 and the red light emitting unit 107 are provided independently of each other, the green light is not absorbed by the light emitting material in the red light emitting unit 107, and thus the green light flux is reduced. In addition, it is possible to prevent the balance of white light components from being disturbed. In FIG. 8, the parts indicated by the same reference numerals as in FIGS. 4 to 7 represent the same parts as in FIGS.

Further, for example, the green light emitting unit 106 and the red light emitting unit 107 may be formed using a surface mounting type frame. Depending on the application of the display device, the backlight unit 101 using the surface mount type frame is often used in this way.
An example of a specific configuration of the light emitting unit 105 using a surface mount type frame is shown in FIG. FIG. 9 is a cross-sectional view schematically showing an example of the configuration of the light emitting unit 105 using a surface-mounting type frame, and parts indicated by the same reference numerals as those in FIGS. 4 to 8 are shown in FIGS. Represents the same thing.

In the configuration of FIG. 9, the green light emitting unit 106 and the red light emitting unit 107 configured in the frame 112 are attached to one side surface of the substrate 104, and the green light emitting unit 106 and the red light emitting unit 107 are paired with the light emitting unit 105. Is forming.
In addition to preventing the green light emitted from the green light emitting unit 106 from passing through the frame 112, the shape, dimensions, and materials (including points that pay attention to heat dissipation, color, and reflectance) are also described in the third embodiment. It is preferable to form in the same manner as the substrate 104 described in detail in the form. In the configuration of FIG. 9, the light emitting unit 105 includes a pair of frames 112, and each frame 112 is formed in a cup shape having a recess, and has a wiring 113 formed so as to connect the bottom of the recess and the lower portion of the frame 112. It shall be provided. Further, a blue light source 108 connected to the wiring 113 is provided in each of the pair of frames 112, and one of the frames 112 is filled with a green light emitting material and a binder to form a green light emitting unit 106. The other frame 112 is filled with a red light emitting material and a binder to form a red light emitting unit 107. Further, it is assumed that a through hole 114 is formed in the substrate 104 and an electrode 110 is attached to the through hole 114. Furthermore, power can be supplied to the electrode 110 from the wiring 109 formed on the back surface of the substrate 104. By connecting the electrode 110 and the wiring 113 of the frame 112 with the solder 115, the blue power supply 108 is connected. Electric power can be supplied. In addition to supplying power to the blue light source 108, the solder 115 functions to fix the green light emitting unit 106 and the red light emitting unit 107 to the substrate 104, and dissipates heat generated by the green light emitting unit 106 and the red light emitting unit 107. It also has a function to make it.

  Even when the light emitting unit 105 is formed using a surface-mounting type frame in this way, part of the blue light emitted from the blue light source 108 is emitted toward the image forming unit 103 as one component of white light, Another part is emitted toward the green light emitting unit 106 and the red light emitting unit 107. The green light emitting unit 106 and the red light emitting unit 107 formed in the recesses are excited by blue light to emit green light and red light, whereby the backlight unit 101 can emit white light. Further, since the green light emitting unit 106 and the red light emitting unit 107 are provided independently of each other, the green light is not absorbed by the light emitting material in the red light emitting unit 107 at the time of light emission. It can suppress that it falls and the balance of the component of white light is disturbed.

  Further, for example, a light guide plate that guides white light from the backlight unit 101 to the image forming unit 103 may be used. If the light guide plate is used, the backlight unit 101 can be disposed at a position other than the position corresponding to the image forming unit 103 as in the above-described embodiment, and the degree of freedom in designing the display device can be increased. Moreover, there is no restriction | limiting in a light-guide plate, A well-known light-guide plate can be used arbitrarily including what utilized a mirror, a prism, a lens, an optical fiber, etc.

  FIG. 10 is a cross-sectional view schematically showing the configuration of a display device using a light guide plate. If the light guide plate is used, for example, as shown in FIG. 10, the backlight unit 101 can be provided on the side of the image forming unit 103. That is, in the configuration of FIG. 10, the light guide plate 117 having the reflection film 116 on the back surface is used. Guide toward the diffusion plate 102 on the upper side in the figure. If the display device is configured as shown in FIG. 10, the backlight unit 101 can be provided on the side of the image forming unit 103. 10, parts indicated by the same reference numerals as those used in FIGS. 4 to 9 are the same as those shown in FIGS.

For example, the display device may further include another member. For example, an antireflection film, a field-of-view expansion film, a brightness enhancement film, a lens sheet, a protective cover, a heat sink, and the like can be appropriately attached.
Furthermore, the configuration described in the description of the light-emitting device and the configuration described in the description of the display device can be combined, or can be implemented by combining the above-described embodiments and modifications.
The configuration of the third embodiment may be realized by a light source or a light emitting material that emits light other than blue, red, and green.
Further, by providing the light emitting device with the third light emitting unit or by providing the backlight unit with a yellow light emitting unit, each of the light emitting device and the backlight unit is configured to include at least three light emitting units. Also good.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and may be arbitrarily modified without departing from the scope of the present invention. it can.

[Example 1]
(Production of green light emitting part)
The green light emitting unit is set such that the chromaticity coordinates of the combined light (short wavelength light) of blue light and green light emitted from the green light emitting unit are (x, y) = (0.25, 0.35). Was made. Specifically, it was as follows.
The frame shown in FIG. 9 is a surface-mount type frame having a recess having a diameter of about 2.5 mm and a depth of about 0.9 mm. A blue LED (blue light source) is provided at the bottom of the recess of the frame. C460 MB made by Cree) was attached so that power could be supplied to the blue light source from the back of the substrate. Further, a green light emitting part was produced by filling a concave part to which a blue light source was attached with a paste in which Ca _2.94 Ce _0.06 Sc _1.94 Mg _0.06 Si ₃ O ₁₂ as a light emitting material and silicon resin as a binder were mixed. At this time, the mixing ratio of the luminescent material and the binder was about 95: 5 by weight.

(Production of red light emitting part)
The red light emitting unit is set such that the chromaticity coordinates of the combined light (long wavelength light) of the blue light and the red light emitted from the red light emitting unit are (x, y) = (0.56, 0.27). Was made. Specifically, the red light-emitting part is formed in the same manner as the green light-emitting part except that Ca _0.992 AlSiEu _0.008 N _2.85 O _0.15 is used as the light-emitting substance and the mixing ratio of the light-emitting substance and the binder is about 98: 2. Produced.

(Measurement of white light)
A current of 20 mA is supplied to each blue LED of the green light emitting part and the red light emitting part to emit light, and for each light emitted from the green light emitting part and the red light emitting part, a spectroscope HR2000 manufactured by Ocean Optics, Using an LED integrating sphere, the emission spectrum distribution was measured. At this time, it was confirmed that the chromaticity coordinates of the emitted light became the set chromaticity coordinates.

Also, based on the measurement results, white light with chromaticity coordinates of (x, y) = (0.33, 0.33) is synthesized from the light emitted from the green light emitting part and the red light emitting part. The emission intensity distribution for each wavelength was calculated. That is, as shown in FIG. 11, on the line segment connecting the chromaticity coordinates of the light emitted from the green light emitting part (short wavelength light) and the chromaticity coordinates of the light emitted from the red light emitting part (long wavelength light). Calculation was performed to adjust the intensity of light emitted from the green light emitting part and the red light emitting part so as to synthesize white light having a chromaticity coordinate located at. In this example, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.48: 0.52. The distribution obtained as a result of the calculation is shown in FIG. FIG. 11 is a chromaticity diagram for explaining the method of synthesizing white light in Examples 1 to 4, and the plots at both ends of each line segment are light emitted from the green light emitting part and the red light emitting part in each Example. Represents the chromaticity coordinates.
Furthermore, the total luminous flux of white light was 1.2 lm per blue LED.

[Example 2]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.27, 0.39) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinate of the combined light (long wavelength light) of blue light and red light is (x, y) = (0.45, 0.22). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, except that the chromaticity coordinate of the white light to be synthesized is (x, y) = (0.32, 0.33), white light is synthesized and emitted with respect to the wavelength in the same manner as in Example 1. The intensity distribution was calculated. In this example, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.50: 0.50. A distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.3 lm per blue LED.

[Example 3]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinates of the combined light (short wavelength light) of blue light and green light are (x, y) = (0.28, 0.42) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the light emitting material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.42, 0.21). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In this example, the spectral ratio of the light from the green light emitting part to the light from the red light emitting part was set to 0.47: 0.53. The distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.3 lm per blue LED.

[Example 4]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.30, 0.47) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the light emitting material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.38, 0.18). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.46: 0.54. The distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.3 lm per blue LED.

[Example 5]
Ca _2.94 Ce _0.06 Sc ₂ Si ₃ O ₁₂ is used as a luminescent substance that emits green light, and the chromaticity coordinates of the combined light (short wavelength light) of blue light and green light are (x, y) = (0.24, 0.24). 0.37) A green light emitting part was produced in the same manner as in Example 1 except that the mixing ratio of the light emitting substance and the binder was adjusted.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.52, 0.26). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.52: 0.48. Moreover, the chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 5-7 is shown in FIG. In FIG. 16, as in FIG. 11, the plots at both ends of each line segment represent the chromaticity coordinates of the light emitted from the green light emitting part and the red light emitting part in each example. A distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.0 lm per blue LED.

[Example 6]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.25, 0.40) Produced a green light emitting part in the same manner as in Example 5.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinate of the combined light (long wavelength light) of blue light and red light is (x, y) = (0.45, 0.22). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present example, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.54: 0.46. The distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.0 lm per blue LED.

[Example 7]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.26, 0.42) Produced a green light emitting part in the same manner as in Example 5.
In addition, the mixing ratio of the light emitting material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.42, 0.21). Otherwise, a red light emitting part was produced in the same manner as in Example 1.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present example, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.54: 0.46. The distribution obtained as a result of the calculation is shown in FIG.
Furthermore, the total luminous flux of white light was 1.0 lm per blue LED.

[Example 8]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.25, 0.35) Produced a green light emitting part in the same manner as in Example 1.
Further, Ca _0.1984 Sr _0.7936 Eu _0.008 AlSiN ₃ is used as the light emitting material of the red light emitting part, and the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.51, 0.29) A red light emitting part was produced in the same manner as in Example 1 except that the mixing ratio of the light emitting material and the binder was adjusted.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.48: 0.52. Moreover, the chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 8-11 is shown in FIG. In FIG. 20, as in FIGS. 11 and 16, the plots at both ends of each line segment represent the chromaticity coordinates of light emitted from the green light emitting portion and the red light emitting portion in each example. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.3 lm per blue LED.

[Example 9]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.27, 0.39) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinate of the combined light (long wavelength light) of blue light and red light is (x, y) = (0.43, 0.24). Otherwise, a red light emitting part was produced in the same manner as in Example 8.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In this example, the spectral ratio of the light from the green light emitting part to the light from the red light emitting part was set to 0.47: 0.53. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.3 lm per blue LED.

[Example 10]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinates of the combined light (short wavelength light) of blue light and green light are (x, y) = (0.28, 0.42) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.40, 0.22). Otherwise, a red light emitting part was produced in the same manner as in Example 8.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.46: 0.54. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.4 lm per blue LED.

[Example 11]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.30, 0.47) Produced a green light emitting part in the same manner as in Example 1.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.36, 0.20). Otherwise, a red light emitting part was produced in the same manner as in Example 8.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.45: 0.55. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.4 lm per blue LED.

[Example 12]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.24, 0.36) Produced a green light emitting part in the same manner as in Example 5.
Further, Ca _0.1984 Sr _0.7936 Eu _0.008 AlSiN ₃ is used as the light emitting material of the red light emitting portion, and the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.48, 0.27) A red light emitting part was produced in the same manner as in Example 1 except that the mixing ratio of the light emitting substance and the binder was adjusted.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.52: 0.48. Moreover, the chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 12-14 is shown in FIG. In FIG. 25, as in FIGS. 11, 16, and 20, the plots at both ends of each line segment represent the chromaticity coordinates of light emitted from the green light emitting portion and the red light emitting portion in each embodiment. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.1 lm per blue LED.

[Example 13]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.26, 0.42) Produced a green light emitting part in the same manner as in Example 5.
In addition, the mixing ratio of the light emitting material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.42, 0.24). Otherwise, a red light emitting part was produced in the same manner as in Example 12.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In this example, the spectral ratio of the light from the green light emitting part to the light from the red light emitting part was set to 0.51: 0.49. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.1 lm per blue LED.

[Example 14]
In addition to adjusting the mixing ratio of the luminescent material and the binder so that the chromaticity coordinate of the combined light (short wavelength light) of blue light and green light is (x, y) = (0.27, 0.45) Produced a green light emitting part in the same manner as in Example 5.
In addition, the mixing ratio of the luminescent material and the binder is adjusted so that the chromaticity coordinates of the combined light (long wavelength light) of blue light and red light are (x, y) = (0.40, 0.22). Otherwise, a red light emitting part was produced in the same manner as in Example 12.

Further, in the same manner as in Example 1, white light was synthesized and the emission intensity distribution with respect to the wavelength was calculated. In the present embodiment, the spectral ratio of the light from the green light emitting part and the light from the red light emitting part was set to 0.52: 0.48. The distribution obtained as a result of the calculation is shown in FIG.
The total luminous flux of white light was 1.1 lm per blue LED.

[Summary]
From the above, it was confirmed that white light can be emitted with a high luminous flux when the green light emitting part and the red light emitting part are provided independently. Furthermore, these white lights include blue, green and red lights, and therefore, if a backlight unit having a green light emitting part and a red light emitting part formed independently of each other as described above is used, A display device with high luminous efficiency and excellent color reproducibility can be obtained.

  The present invention can be used in any field using light. For example, in addition to indoor and outdoor lighting, various electronic devices such as mobile phones, household appliances, outdoor installation displays, liquid crystal displays and liquid crystal projectors can be used. It is suitable for use in image display devices, internal lighting signs, and the like.

It is a figure which shows typically the principal part of the light-emitting device as 1st Embodiment of this invention, Fig.1 (a) is the sectional drawing, FIG.1 (b) is the disassembled perspective view. It is a figure which shows typically the principal part of the light-emitting device as 2nd Embodiment of this invention, Fig.2 (a) is the sectional drawing, FIG.2 (b) is the perspective view. It is a figure showing typically a section of an important section of a display in order to explain an example of a backlight unit using a light emitting device of the present invention. It is a typical disassembled perspective view explaining the outline | summary of the display apparatus as 3rd Embodiment of this invention. It is a typical top view of the backlight unit in a 3rd embodiment of the present invention. It is typical sectional drawing for demonstrating the principal part of the backlight unit in 3rd Embodiment of this invention. It is a chromaticity diagram for demonstrating a preferable range as a color coordinate of the light which synthesize | combined blue light and green light in the display apparatus in 3rd Embodiment of this invention. It is typical sectional drawing for demonstrating the principal part of the backlight unit in the modification of 3rd Embodiment of this invention. It is sectional drawing which shows typically an example of a structure of the light emission part using the surface mounting type flame | frame of the backlight unit in the modification of 3rd Embodiment of this invention. It is sectional drawing which represents typically the structure of the display apparatus using a light-guide plate as a modification of 3rd Embodiment of this invention. It is a chromaticity diagram for demonstrating the synthetic | combination method of the white light in Examples 1-4 of this invention. It is a graph showing the light emission intensity distribution with respect to the wavelength of white light calculated in Example 1 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 2 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 3 of this invention. It is a graph showing the light emission intensity distribution with respect to the wavelength of white light calculated in Example 4 of this invention. It is a chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 5-7 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 5 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 6 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 7 of this invention. It is a chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 8-11 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 8 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 9 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light calculated in Example 10 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light computed in Example 11 of this invention. It is a chromaticity diagram for demonstrating the synthesis | combination method of the white light in Examples 12-14 of this invention. It is a graph showing the light emission intensity distribution with respect to the wavelength of white light calculated in Example 12 of this invention. It is a graph showing the light emission intensity distribution with respect to the wavelength of white light calculated in Example 13 of this invention. It is a graph showing the emitted light intensity distribution with respect to the wavelength of white light computed in Example 14 of this invention.

Explanation of symbols

1, 11 Light emitting device 1A, 11A Light emission surface 2, 12 Frame 2A, 12A Recess 2B Insertion portion 3, 13 Blue LED (light source)
4,14 Green light emitting part (first light emitting part)
4A 1st light emission surface 5,15 Red light emission part (2nd light emission part)
5A 2nd light emission surface 6 Partition plate (light-shielding part)
16 Partition wall (shading part)
7, 17 Silver paste 8, 18 Wire 19 Beam 21 Display 22 Liquid crystal display unit 23 Light guide plate 24 Light-emitting device 25 Backlight unit 101 Backlight unit 102 Diffuser plate 103 Image forming unit 104 Substrate 105 Light-emitting unit 106 Green light-emitting unit 107 Red light emission Portion 108 Blue light source 109 Wiring 110 Electrode 111 Beam 112 Frame 113 Wiring 114 Through hole 115 Solder 116 Reflective film 117 Light guide plate

Claims (9)

A light source;
A first light emitting part containing at least one luminescent material capable of emitting light containing a component having a longer wavelength than the light emitted from the light source when excited by the light emitted from the light source;
A second light-emitting part containing at least one light-emitting substance capable of emitting light including a component having a longer wavelength than light emitted from the light source and the light emitted from the first light-emitting part;
A light-emitting device comprising: a light-blocking unit that prevents at least a part of light emitted from the first light-emitting unit from entering the second light-emitting unit. The light-emitting device according to claim 1, wherein the light-shielding portion reflects at least a part of light emitted from the first light-emitting portion. An illumination using the light-emitting device according to claim 1. A backlight unit for a display device, wherein the light emitting device according to claim 1 or 2 is used. A display device using the light-emitting device according to claim 1. A backlight unit that emits a backlight; and
An image forming unit that irradiates the backlight emitted from the backlight unit on the back side and forms an image on the front side,
The backlight unit is
A light source;
A first light emitting part containing at least one luminescent material capable of emitting light containing a component having a longer wavelength than the light emitted from the light source when excited by the light emitted from the light source;
It is formed at least partly independently from the first light emitting unit, and is excited by light emitted from the light source and the first light emitting unit, and can emit light containing a component having a longer wavelength than the light emitted from the first light emitting unit. A display device comprising: a second light-emitting portion containing at least one light-emitting substance. A backlight unit that emits white light;
An image forming unit that irradiates the white light emitted from the backlight unit on the back side and forms an image on the front side,
The backlight unit is
A blue light source emitting blue light;
A green light-emitting unit that emits green light having a green light-emitting body that emits light when excited by the blue light;
A display device, comprising: a red light emitting portion that is formed at least partly independently from the green light emitting portion, has a red light emitting body that emits light when excited by the blue light, and emits red light. The display device according to claim 6, further comprising a diffusion plate that diffuses light emitted from the backlight unit between the backlight unit and the image forming unit. The display device according to claim 6, further comprising a light guide plate that guides light from the backlight unit to the image forming unit.

Images