JP2012060058A - Light emitting device, liquid crystal projector including the light emitting device, and method of manufacturing the light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device capable of emitting light beams without luminance unevenness and efficiently emitting the light beam emitted from a light source.SOLUTION: The light emitting device 10 related to this invention includes: a substrate 11 provided with a light source arrangement region 11a and an out-of-light-source-arrangement region 11b; a light source 12 which is arranged inside the light source arrangement region 11a on the substrate 11 and emits the light beam at least from an upper surface; a transmission member 13 which is arranged above the light source 12 and transmits the light beam emitted from the light source 12 from a prescribed irradiation region 13a; and a reflection member 14 which is arranged in a space between the substrate 11 and the transmission member 13, reflects the light beam and is filled in the state of positioning the upper surface end around the irradiation region 13a of the transmission member 13 in a part of the space between the substrate 11 and the transmission member 13. In this case, the irradiation region 13a of the transmission member 13 is included in a region facing the light source arrangement region 11a of the substrate 11.

Description

  The present invention relates to a light emitting device that emits light, and more particularly to a light emitting device that emits light emitted from an LED (Light Emitting Diode) light source via a wave plate or a polarizer.

  Generally, a high-luminance LED light source is used as a light source for a liquid crystal projector or the like. For example, in a liquid crystal projector, light emitted from an LED light source enters a reflective polarizer, transmits only specific polarized light, and reflects other specific polarized light. Only light rays that have passed through the reflective polarizer are used for image display.

  However, when the light beam reflected from the reflective polarizer is not used for image display, the utilization efficiency of the light beam is poor. Thus, for example, Patent Documents 1-3 disclose a technique for efficiently emitting light emitted from an LED light source from an irradiation surface. 9A is a cross-sectional view of the light-emitting device of Patent Document 1, FIG. 9B is a cross-sectional view of the light-emitting device of Patent Document 2, and FIG. 9C is a cross-sectional view of the light-emitting device of Patent Document 3. Show.

  In FIG. 9A, a light emitting device 90A of Patent Document 1 polarizes a light beam emitted from an LED light source 91A and reflected from a reflective polarizer 93A by way of a wave plate 92A, and again a reflective polarized light. The light is incident on the child 93A and is emitted from the reflective polarizer 93A.

  In FIG. 9B, the light emitting device 90B of Patent Document 2 includes a photonic crystal body 94B on the light emitting surface of the LED light source 91B in addition to the wave plate 92B and the reflective polarizer 93B. Then, the light beam reflected from the reflective polarizer 93B is rotated by 180 degrees in phase in the photonic crystal body 94B, and is incident on the reflective polarizer 93B again to be transmitted.

  In FIG. 9C, the light emitting device 90C of Patent Document 3 has an arcuate fluorescent member 95C that spreads upward on the side of the LED light source 91C, and emits light emitted to the side of the LED light source 91C. The light is incident on the fluorescent member 95C, and the colored light is emitted from the upper surface side of the light emitting device 90C.

Japanese Patent Laying-Open No. 2005-079104 JP 2007-034012 A JP 2003-142737 A

  Here, the brightness of the light emitted from the irradiation surface of the light emitting device is different between directly above and around the LED light source, the central area directly above the LED light source is bright, and dark around it. For example, when the light emitting devices 90A to 90C of Patent Documents 1-3 are used as a light source for a liquid crystal projector, it is substantially possible to use any of the light emitting devices 90A to 90C in a light beam emitted from an irradiation surface. Only the light in the central area is used, and the light in the surrounding area is wasted.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and is capable of emitting a light beam having no luminance unevenness and efficiently emitting a light beam emitted from a light source. An object of the present invention is to provide a liquid crystal projector provided and a method for manufacturing the light emitting device.

  In order to achieve the above object, a light-emitting device according to the present invention includes a substrate having a light source arrangement region and a light source arrangement outside region, a light source arranged in the light source arrangement region on the substrate, and emitting light from at least the upper surface, A transmissive member that is disposed above the light source and transmits the light beam emitted from the light source from a predetermined irradiation region, and reflects the light beam. The upper surface end portion is a transmissive member in a part of the space between the substrate and the transmissive member And a reflecting member filled in a state of being positioned around the irradiation region. Here, the irradiation region of the transmissive member is included in a region facing the light source arrangement region of the substrate.

  In order to achieve the above object, a liquid crystal projector according to the present invention includes the above light emitting device.

  In order to achieve the above object, a method of manufacturing a light emitting device according to the present invention includes a light source that emits light from at least an upper surface in a light source arrangement region on a substrate, and a reflecting member that reflects the light is provided at an end of the upper surface. Is arranged around the light source on the substrate so that the light beam emitted from the light source is transmitted from the irradiation region. Here, the irradiation region of the transmissive member is included in a region facing the light source arrangement region of the substrate.

  According to the present invention, it is possible to provide a light emitting device that can emit a light beam having no luminance unevenness and can efficiently emit a light beam emitted from a light source, a liquid crystal projector including the light emitting device, and a method for manufacturing the light emitting device. can do.

It is an example of sectional drawing of the light-emitting device 10 which concerns on the 1st Embodiment of this invention. 1 is an example of a plan layout view of a light emitting device 10 according to a first embodiment of the present invention. It is an example of sectional drawing of the light-emitting device 100 which concerns on the 2nd Embodiment of this invention. It is an example of the plane arrangement view of the light emitting device 100 according to the second embodiment of the present invention. It is a figure which shows the manufacturing process of the light-emitting device 100 which concerns on the 2nd Embodiment of this invention. It is an example of sectional drawing of the light-emitting device 100B which concerns on the 3rd Embodiment of this invention. It is an example of sectional drawing of 100 C of light-emitting devices which concern on the 4th Embodiment of this invention. It is an example of sectional drawing of light-emitting device 100D which concerns on the 5th Embodiment of this invention. FIG. 4A is an example of a sectional view of a light emitting device 90A, FIG. 5B is an example of a sectional view of a light emitting device 90B, and FIG. 5C is an example of a sectional view of a light emitting device 90C.

(First embodiment)
A first embodiment will be described. An example of a cross-sectional view of the light emitting device according to the present embodiment is shown in FIG. 1, and an example of a plan layout is shown in FIG. 1 and 2, the light emitting device 10 includes a substrate 11, a light source 12, a transmission member 13, and a reflection member 14.

  The board | substrate 11 is divided into the light source arrangement | positioning area | region 11a for arrange | positioning the light source 12, and the other light source arrangement | positioning area | region 11b.

  The light source 12 is disposed in the light source arrangement region 11a on the substrate 11, and emits light rays at least from the upper surface in the upward direction.

  The transmissive member 13 is disposed above the light source 12 and transmits the light emitted from the light source 12 from the irradiation region 13a. Further, in FIG. 1, the transmissive member 13 is supported by the reflective member 14, thereby being held at a position keeping a certain distance from the substrate 11. In the present embodiment, the light beam emitted from the light source 12 is emitted to the outside of the light emitting device 10 only from the irradiation region 13 a of the transmission member 13.

  The reflecting member 14 reflects the incident light beam. In the present embodiment, the reflecting member 14 is filled in a part of the space between the substrate 11 and the transmissive member 13. And the irradiation area | region 13a of the transmissive member 13 is formed by positioning the upper surface edge part of the filled reflective member 14 in the predetermined position of the transmissive member 13. FIG. Here, as shown in FIGS. 1 and 2, the irradiation region 13 a of the transmission member 13 is included in the light source arrangement region 11 a of the substrate 11.

  In the light emitting device 10 configured as described above, most of the light emitted from the upper surface of the light source 12 travels upward as it is and is emitted from the irradiation region 13 a of the transmission member 13 to the outside of the light emitting device 10. A part of the light beam emitted from the upper surface of the light source 12 travels in an oblique direction, is reflected by the reflecting member 14, and then is emitted from the irradiation region 13 a to the outside of the light emitting device 10.

  Here, after being reflected by the reflecting member 14, the light beam emitted from the irradiation region 13a has a lower luminance than the light beam that travels upward and is emitted from the irradiation region 13a as it is. The light emitting device 10 according to the present embodiment includes the irradiation region 13a inside the light source arrangement region 11a, so that the irradiation region 13a does not include high-luminance light rays that travel upward from the upper surface of the light source 12 as they are. A region is not formed. Therefore, a light beam having no luminance unevenness can be emitted from the irradiation region 13a.

  Further, the light beam emitted from the upper surface of the light source 12 and traveling in the oblique direction is reflected by the reflecting member 14 and is emitted from the irradiation region 13a to the outside. Therefore, the light emitted from the light source 12 can be efficiently emitted.

  In the present embodiment, as shown in FIGS. 1 and 2, the irradiation region 13 a of the transmissive member 13 is formed to be approximately the same size as the light source arrangement region 11 a of the substrate 11. However, the irradiation area of the transmissive member 13 only needs to be substantially included in an area corresponding to the light source arrangement area 11 a of the substrate 11, and the irradiation area of the transmissive member 13 is physically smaller than the light source arrangement area 11 a of the substrate 11. This is not a condition.

On the other hand, the irradiation area of the transmission member 13 can be made smaller than the light source arrangement area 11 a of the transmission member 13. In this case, the brightness of the light beam emitted from the irradiation area is increased.
(Second Embodiment)
A second embodiment will be described. In the present embodiment, a light-emitting device intended to be used for a liquid crystal projector will be mainly described. An example of a cross-sectional view of the light emitting device according to this embodiment is shown in FIG. In FIG. 3, the light emitting device 100 according to the present embodiment includes a substrate 110, an electrode 120, an LED chip 130, a support frame 140, a wave plate 150, a polarizer 160, a reflective resin 170, and a gold wire 180.

  A plurality of electrodes 120 for electrical wiring are formed on the substrate 110. A support frame 140 is disposed on the electrode 120 in a region outside the light source arrangement (not shown).

  The LED chip 130 emits a light beam having a predetermined wavelength from the light emitting region on the upper surface. In FIG. 3, the LED chip 130 is arranged on the electrode 120 in the light source arrangement region (not shown), and is electrically connected to the electrode 120 in the light source arrangement outside region via the gold wire 180.

  The support frame 140 is disposed in an end region on the substrate 110 and supports the wave plate 150 and the polarizer 160.

  The wave plate 150 is disposed on the support frame 140 and covers the LED chip 130. In the present embodiment, the wave plate 150 rotates the polarization state of the light beam by 90 degrees by transmitting the light beam emitted from the LED chip 130 twice.

  The polarizer 160 is disposed on the wave plate 150 and transmits only specific polarized light and reflects other specific polarized light. The other specific polarized light reflected from the polarizer 160 is converted into specific polarized light by passing through the wave plate 150 twice, and then transmitted from the polarizer 160.

  The reflective resin 170 is a paste-like resin obtained by mixing an appropriate amount of a light diffusing agent, for example, barium sulfate, aluminum oxide, titanium oxide, or the like with a transparent epoxy resin or a transparent silicone resin. The reflective resin 170 is filled in the gap between the substrate 110 and the wave plate 150 so that the emission area of the specific polarized light of the polarizer 160 (irradiation surface of the light emitting device 100) and the arrangement area of the LED chip 130 substantially coincide. The Further, as shown in FIG. 3, the reflective resin 170 is disposed so as to be in contact with the edge of the upper surface of the LED chip 130 and not to cover the light emitting region of the upper surface of the LED chip 130. In the present embodiment, the reflective resin 170 is further disposed between the side surfaces between the LED chips 130.

  The region where the reflective resin 170 is disposed will be described with reference to FIG. In FIG. 4, eight electrodes 120a to 120h are formed on a substrate 110, and four LED chips 130a to 130d are respectively disposed on the electrodes 120a to 120d. The LED chips 130a to 130d are electrically connected to the electrodes 120e to 120h via gold wires 180a to 180d, respectively.

  The reflection resin 170a has an upper surface end portion of the reflection resin 170a (dotted drawing) at an end portion of the arrangement region of the LED chip 130 (hatched drawing) in the region where the LED chip 130 inside the support frame 140 is not arranged. The substrate 110 to the wave plate 150 are filled so as to be positioned. A region surrounded by the upper end portion of the reflective resin 170 a is an emission region of the polarizer 160. Further, the reflective resin 170b is disposed between the side surfaces of the LED chips 130a to 130d.

  The light emitting device 100 configured as described above is emitted from the irradiation surface of the light emitting device 100 because the reflective resin 170a is filled so that the emission region of the polarizer 160 substantially coincides with the arrangement region of the LED chip 130. In addition, the luminance of the specific polarized light becomes uniform, and the specific polarized light can be converged and emitted to the emission region of the polarizer 160.

  Further, since the reflection resin 170a is applied so as to contact the edge of the upper surface of the LED chip 130 and not to cover the light emitting region of the upper surface of the LED chip 130, the light is reflected in the immediate vicinity of the LED chip 130. The specific polarization of the light emitted from the LED chip 130 can be efficiently emitted from the emission region of the polarizer 160. Furthermore, by filling the reflective resin 170b between the side surfaces of the LED chip 130, the specific polarized light can be emitted more efficiently.

  Next, a method for manufacturing the light emitting device 100 according to this embodiment will be described. FIG. 5 shows an example of a manufacturing process diagram of the light emitting device 100.

  First, in FIG. 5A, the electrode 120 is formed on the substrate 110 by printing or the like. Further, the LED chip 130 is mounted on the electrode 120 with a brazing material such as silver paste or AuSn solder. The front and back surfaces of a general LED chip 130 are electrodes. In this embodiment, the front surface side electrode of the LED chip 130 is electrically connected to the electrode 120 of the substrate 110 using a gold wire 180. Further, a support frame 140 for supporting the wave plate 150 and the polarizer 160 is disposed in the end region on the substrate 110 around the LED chip 130.

  Although only one large LED chip can be used as the LED chip 130, the quality of the large LED chip may not be stable, and the unit price is high. Therefore, it is desirable to arrange a plurality of LED chips in a straight line or in a grid.

  Next, in FIG. 5B, a reflective resin 170b is applied between the side surfaces of the LED chip 130 using a dispenser or the like. Further, the reflective resin 170 a is applied between the LED chip 130 and the support frame 140 so that the upper surface end is positioned at the corresponding position of the end of the arrangement region of the LED chip 130. At this time, the reflective resin 170 a is applied so as to be in contact with the edge of the upper surface of the LED chip 130 and not to cover the light emitting region on the upper surface of the LED chip 130. In addition, since a paste-like resin is used as the reflective resin 170a, the reflective resin 170a can be applied on the gold wire 180.

  Further, in FIG. 5C, the wave plate 150 is disposed on the support frame 140 and the reflection resin 170a, and in this state, the reflection resins 170a and 170b are cured, and the wave plate 150 is bonded and fixed. If the bonding strength between the reflective resin 170a and the wave plate 150 is insufficient, an adhesive is applied between the support frame 140 and the wave plate 150 for fixing. In the present embodiment, the light emitting device 100 is heated to thermally cure the reflective resins 170a and 170b and the adhesive. Thereafter, a polarizer 160 is attached on the wave plate 150.

  In addition, you may fix the wave plate 150 with which the polarizer 160 was affixed previously on the support frame 140 and the reflection resin 170a. Further, the wave plate 150 and the polarizer 160 can be held without being attached with a predetermined distance.

  In the light emitting device 100 formed as described above, the light emitted from the LED chip 130 passes through the wave plate 150 and enters the polarizer 160. In the light ray incident on the polarizer 160, the specific polarization is transmitted from the polarizer 160, and the other specific polarization is reflected from the polarizer 160. Then, the other specific polarized light reflected from the polarizer 160 is converted into the specific polarized light by passing through the wave plate 150 twice and transmitted from the polarizer 160.

  Here, since the reflection resin 170a is disposed by positioning the upper end at the position corresponding to the end of the arrangement area of the LED chip 130, the emission area of the polarizer 160 substantially coincides with the arrangement area of the LED chip 130. Accordingly, the luminance of the specific polarized light emitted from the irradiation surface of the light emitting device 100 is uniform, and the specific polarized light can be converged and emitted within the range of the irradiation surface of the light emitting device 100. When the specific polarized light is converged and emitted within the range of the irradiation surface of the light emitting device 100, it is possible to provide an optimal light emitting device as a light source for a liquid crystal projector that requires high luminance and uniform light quantity.

  In addition, the reflective resin 170a is applied so as to be in contact with the edge of the upper surface of the LED chip 130 and not to cover the light emitting region on the upper surface of the LED chip 130, thereby reflecting the light beam in the immediate vicinity of the LED chip 130. The specific polarization of the light beam can be emitted efficiently. Furthermore, by arranging the reflective resin 170b between the side surfaces of the LED chip 130, the specific polarized light can be emitted more efficiently.

  Note that the light emitting device 100 according to the present embodiment is not limited to a light emitting device that emits specific polarized light. In this case, the wave plate 150 and the polarizer 160 can be omitted. Further, when sufficient illuminance is obtained, the reflective resin 170b can be omitted between the side surfaces of the LED chip 130. When the application of the reflective resin 170b is omitted, the light-emitting device 100 with low manufacturing cost can be provided.

  In the present embodiment, the reflective resin 170a is arranged so that the emission area of the polarizer 160 substantially coincides with the arrangement area of the LED chip 130. However, it is not always necessary to coincide with the arrangement area of the LED chip 130. By setting the emission area of the polarizer 160 to be equal to or smaller than the arrangement area of the LED chip 130, the luminance of the specific polarized light emitted from the irradiation surface of the light emitting device 100 is uniform. In addition, the specific polarized light can be converged and emitted within the optimum range.

  In addition to the liquid crystal projector, the light emitting device 100 according to the present embodiment can be applied to various devices such as a liquid crystal display device and an image reading device in which it is desirable to apply a light beam without uneven brightness.

(Third embodiment)
A third embodiment will be described. The light emitting device according to the present embodiment is obtained by removing the support frame 140 from the light emitting device 100 of the second embodiment shown in FIG. An example of a cross-sectional view of the light emitting device according to the third embodiment is shown in FIG. In FIG. 6, the wave plate 150 is supported above the LED chip 130 by only the reflective resin 170.

  Since the light emitting device 100B according to the present embodiment does not use the support frame 140, the light emitting device 100B can be made smaller than the light emitting device 100 of FIG. 3 and the cost can be reduced.

(Fourth embodiment)
A fourth embodiment will be described. An example of a cross-sectional view of the light emitting device according to the fourth embodiment is shown in FIG. In the light emitting device 100 </ b> C illustrated in FIG. 7, the wave plate 150 and the polarizer 160 are held in a state where a predetermined distance is maintained.

  In the light emitting device 100 </ b> C according to the present embodiment, after the wave plate 150 is bonded and fixed on the reflective resin 170 a, the reflective resin 170 c is applied on the reflective resin 170 a so as to cover the end of the wave plate 150. To do. At this time, at the end of the wave plate 150, the reflective resin 170c is piled up to a desired height in a range where the emission area of the polarizer 160 substantially coincides with the arrangement area of the LED chip 130.

  And after arrange | positioning the polarizer 160 on the reflective resin 170c piled up to desired height, the reflective resin 170a-170c is thermosetted. When the reflective resins 170a to 170c are thermally cured, the wave plate 150 and the polarizer 160 are held at a predetermined distance.

  In the case of the light emitting device 100 </ b> C illustrated in FIG. 7, the light beam traveling in the lateral direction between the polarizer 160 and the wave plate 150 is also converged in an area corresponding to the arrangement area of the LED chip 130 of the polarizer 160. Are emitted from the emission region.

(Fifth embodiment)
A fifth embodiment will be described. An example of a cross-sectional view of the light emitting device according to this embodiment is shown in FIG. The light emitting device 100D according to the present embodiment fills the gap between the LED chip 130 and the reflective resin 170d molded so that the space through which the light passes is narrowed upward instead of the paste-like reflective resin. And a reflective resin 170e molded in the above.

  In the present embodiment, a quadrangular pyramid-shaped solid resin whose cross-sectional area increases upward is used as the reflective resin 170d, and a square that fits between the side surfaces of the LED chip 130 as the reflective resin 170e. A columnar solid resin is used. Further, in the present embodiment, a recess for accommodating the gold wire 180 is formed in the reflective resin 170d. In FIG. 8, by disposing the above-described reflective resin 170d in the outer region of the LED chip 130, the space through which the light beam passes from the substrate 110 side toward the wave plate 150 side becomes narrower.

  The light emitting device 100D according to this embodiment is manufactured as follows. That is, the LED chip 130 is disposed on the substrate 110, and the LED chip 130 is electrically connected to the electrode 120 through the gold wire 180.

  In this state, the reflective resin 170e is disposed between the LED chips 130 on the substrate 110 and bonded and fixed. Further, the reflective resin 170d is disposed in the outer region of the LED chip 130 on the substrate 110 in a state where the gold wire 180 is accommodated in the concave portion, and is bonded and fixed. At this time, the upper end portion of the reflective resin 170d is located at the corresponding position of the end portion of the arrangement region of the LED chip 130. After the reflective resin 170d and the reflective resin 170e are bonded and fixed on the substrate 110, the wave plate 150 and the polarizer 160 are fixed on the reflective resin 170d.

  In the light emitting device 100D according to the present embodiment, the light emitted from the LED chip 130 in the direction outside the arrangement region of the LED chip 130 is not reflected immediately, but the irradiation surface of the light emitting device 100D is almost in the arrangement region of the LED chip 130. Accordingly, it is possible to emit specific polarized light having no luminance unevenness, and to emit specific polarized light converged in an optimum range.

  Further, by using the reflection resins 170d and 170e that are pre-shaped into a predetermined shape instead of the paste-like reflection resin, the arrangement of the reflection resins 170d and 170e is facilitated, and the cost can be reduced. Furthermore, when the reflective resin 170d is formed into a quadrangular pyramid so as not to be in direct contact with the LED chip 130, direct transmission of heat from the LED chip 130 can be avoided. Therefore, a material with slightly low heat resistance can be used as the material of the reflective resin 170d.

  In this embodiment, the reflective resin 170d in which the concave portion for storing the gold wire 180 is used in advance is used. However, when the reflective resin 170d is disposed outside the gold wire 180, the concave portion is provided in the reflective resin 170d. It does not have to be formed.

DESCRIPTION OF SYMBOLS 10 Light-emitting device 11 Substrate 12 Light source 13 Transmission member 14 Reflective member 100, 100B, 100C, 100D Light-emitting device 110 Substrate 120 Electrode 130 LED chip 140 Support frame 150 Wave plate 160 Polarizer 170 Reflective resin 180 Gold wire

Claims (10)

A substrate comprising a light source placement area and a light source placement outside area;
A light source arranged in the light source arrangement region on the substrate and emitting light from at least the upper surface;
A transmission member that is disposed above the light source and transmits a light beam emitted from the light source from a predetermined irradiation region;
A reflecting member that reflects the light beam and is filled in a part of a space between the substrate and the transmitting member in a state where an upper end is positioned around the irradiation region of the transmitting member;
With
The light emitting device according to claim 1, wherein the irradiation region of the transmissive member is included in a region facing a light source arrangement region of the substrate. The light emitting device according to claim 1, wherein a side surface of the reflecting member on a light source side is in contact with an end portion of the upper surface of the light source. There are two or more light sources,
The light emitting device according to claim 1, further comprising a second reflecting member that is filled between side surfaces of the two or more light sources and reflects the light beam. The light-emitting device according to claim 1, wherein the transmission member is a polarizer that transmits only predetermined polarized light and reflects other polarized light. The light emitting device according to claim 4, further comprising a wave plate that is disposed between the polarizer and the light source and changes a phase of the light beam. The reflective member is
A third reflecting member filled in a part of the space between the substrate and the wave plate in a state where the upper surface end is positioned around the irradiation region;
A fourth reflecting member that is filled from above the wave plate and the third reflecting member to the polarizer in a state where an upper end is positioned around the irradiation region;
The light emitting device according to claim 5. The light-emitting device according to claim 1, wherein the reflecting member is a mixture of a transparent resin and a light diffusing agent. The light-emitting device according to claim 1, wherein the light source is an LED light source. A liquid crystal projector comprising the light emitting device according to claim 1. In the light source arrangement area on the substrate, arrange a light source that emits light from at least the upper surface,
The reflecting member that reflects the light beam is disposed around the light source on the substrate such that the upper end is positioned around the irradiation region of the transmitting member,
A transmissive member that transmits the light emitted from the light source from the irradiation region is disposed on the reflective member.
A method of manufacturing a light emitting device,
The method of manufacturing a light emitting device, wherein the irradiation region of the transmissive member is included in a region facing a light source arrangement region of the substrate.

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