JP2009186701A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and inexpensive image display device which is excellent in efficiency of cooling a lens and a light emitting element or the like. <P>SOLUTION: A ventilation device 22 takes air in to the image display device. After the taken-in air reaches radiation fins 21 of a radiator 20 and passes through a gap between the fins 21, it is branched to two directions. A part of the air flows to the radiator 20br side and the rest of the air flows to a space on a green light source 10g side. After a part of the air passes through the gap between the radiation fins 21 of the radiator 20br, it is discharged to the outside of the image display device. The rest of the air reaches a space just above the green light source 10g, and passes between a lens 23 and a light emitting element 50 of the green light source 10g. Furthermore, the air successively reaches spaces just above a blue light source 10b and a red light source 10r. The rest of the air passes between the light emitting element 50 of the blue light source 10b and the lens 23 opposed thereto, and the light emitting element 50 of the red light source 10r and the lens 23 opposed thereto, and passes through peripheral areas of the members. The air bypasses the radiator 20br and is discharged to the outside of the image display device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video display device.

  Patent Document 1 discloses a projector in which a holding member (lens holder) of an optical element (projection lens) is provided with fins as heat radiating portions. In the projector described in Patent Document 1, the heat generated in the optical element is transferred to the holding member of the optical element, and then radiated from the radiating fin that is a heat radiating portion provided in the holding member.

JP 2006-139022 A

  However, the conventional video display device having the structure described in the projector of Patent Document 1 has a problem that heat generated in an optical element such as a lens cannot be sufficiently cooled. . For example, when the brightness of the light source is improved, the energy of light passing through the optical element increases, so that the heat generated in the optical element increases, so that the optical element can be sufficiently cooled. Absent.

  In particular, in the structure of the projector described in Patent Document 1, since the contact area between the holding member of the optical element provided with the heat radiating portion and the optical element is limited, the optical element to the holding member of the optical element is limited. There is a limit to the amount of heat transfer, and the heat generated in the optical element cannot be sufficiently conducted to the holding member of the optical element, and as a result, the optical element cannot be cooled sufficiently. There is. Further, in the projector structure described in Patent Document 1, when the contact area between the optical element and the holding member is set large, the optical element becomes large, which increases the size of the video display device and the material cost. There is a problem of causing an increase. Furthermore, when the heat radiating portion provided in the holding member is set large, there is a problem in that the holding member becomes large, leading to an increase in the size of the video display device and an increase in material cost.

  The present invention has been made to overcome the above-described problems, and an object of the present invention is to realize a small and inexpensive video display device that is excellent in cooling efficiency of optical elements such as lenses.

  The subject of the present invention is a light source including a light emitting element that emits visible light, a radiator including a radiation fin provided on a back surface facing the surface, and air flowing to the radiator. A blower for flowing the air and a lens for refracting the visible light emitted from the light source, wherein the light source is thermally connected to the surface of the radiator The lens is disposed so as to form a space between the light source and the image display device, wherein air passing through a gap between the heat dissipating fins of the radiator further includes the light source and the lens. A flow path for flowing through the space formed between the two is provided.

  According to the subject of the present invention, the space formed between the light emitting element of the light source and the lens functions as a flow path for the outside air blown from the blower, so that the light emitted from the light emitting element passes through the lens. The temperature rise due to the heat generation of the lens at the time can be suppressed, and the temperature rise of the light emitting element can also be suppressed. In addition, since the radiator itself also forms a flow path for the outside air, an increase in the temperature of the radiator can be suppressed. As a result, even when a large amount of power is applied to the light source to improve the brightness of light emitted from the light source, the lens can be sufficiently cooled and the light emitting element can be sufficiently cooled. I can do it. In addition, since the deterioration of the lens material due to the temperature rise can be reduced, the durability of the lens can be improved. Furthermore, since the cooling efficiency of the lens and the light emitting element is improved and the amount of air flowing through the video display device by the blower can be reduced, the noise generated by the blower can be reduced.

  Hereinafter, various embodiments of the subject of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is an exploded perspective view schematically showing the internal structure of the video display apparatus according to the present embodiment. FIG. 2 is an exploded perspective view showing only main members of the video display apparatus shown in FIG. FIG. 3 is a cross-sectional view of the structure shown in FIG. 2 as viewed from above, and is a view for describing the flow of air. FIG. 4 is an exploded perspective view schematically showing a part of the housing and the lens 23 of the optical engine 11 of the video display device according to the present embodiment. Further, FIG. 5 is a schematic perspective view schematically showing a configuration of the light source 10 used in the video display apparatus according to the present embodiment shown in FIG. In the above drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description thereof will not be repeated. Hereinafter, the video display device according to the present embodiment will be described in detail with reference to FIGS.

  The video display device according to the present embodiment is summarized as follows: (1) a light source including a light emitting element that emits visible light in a planar shape; (2) a radiator including a heat radiation fin; and (3) a video display. An air blower for causing the air in the video display device to flow by taking outside air around the device and blowing it into the video display device; and (4) refracting visible light emitted from the light source at a predetermined angle. And at least a lens.

  The light source is thermally connected to the radiator. Here, “thermally connected” means a state in which heat transfer causes heat transfer between the two members.

  The lens is relatively relative to the light source so as to create a space through which air can flow between one surface of the light source on which the light emitting element is thermally connected. Has been placed.

  The air blower blows the outside air around the video display device taken in through the air inlet provided in the design housing of the video display device toward the radiator in the video display device, so that It arrange | positions with respect to a heat radiator so that air can be made to flow in an image display apparatus by allowing air to pass along.

  In the video display device according to the present embodiment, the air inside the video display device is caused to flow by passing the outside air (air) taken into the video display device by the blower through the gaps of the heat radiating fins of the radiator. The heat of the radiator is taken away by heat transfer generated between the radiator and the radiation fin. Similarly, in the present video display device, a part of the air that has passed through the gap between the radiator fins of the radiator and has exited from the outlet side of the radiator fin is formed between the light emitting element of the light source and the lens. The lens, the light emitting element, and the heat radiator are caused by heat transfer between the air and the lens, the air and the light emitting element, and the air and the radiator by flowing in the flow path including the space. Take away the heat of each.

  In this way, in this image display device, the space on the light emitting element side of the light source and the space on the heat radiating fin side of the radiator can be cooled by the flow of air blown by the blower device, so the light source can be efficiently cooled together with the lens A possible structure has been realized.

  First, constituent members of the video display device will be described below.

  As shown in FIG. 1, this image display device includes (1) a blue light source 10b having a wavelength near 460 nm and emitting blue light, and (2) a green light source 10g having a wavelength near 525 nm and emitting green light. (3) a red light source 10r having a wavelength near 625 nm and emitting red light. In the following description, reference numeral “10” is used to indicate each light source without specifying individual light sources.

  As shown in FIG. 5, the light source 10 is mainly composed of a light emitting element 50 and a metal circuit board 51. In this example, the light emitting element 50 is a semiconductor element that is formed of a light emitting diode, that is, an LED (Light Emitting Diode), and emits light by applying a predetermined voltage to flow a current. In addition, in this example, since the existing light emitting diode is used for the light emitting element 50, the detailed description regarding a light emitting diode is omitted.

  The light emitting element 50 is a surface light source that emits light in a planar shape with a light emitting surface formed in a square shape. The light emitting element 50 emits visible light. The material constituting the light emitting element 50 emits blue light, green light, and red light. The light emitting element 50 is disposed and mounted substantially at the center of the metal circuit board 51. In other words, the light emitting element 50 is thermally connected to one surface (front surface) 51S1 of the metal circuit board 51. As a material for the metal circuit board 51, it is desirable to use a material having high thermal conductivity in order to diffuse heat efficiently. More specifically, it is desirable to use a material having a thermal conductivity of 50 W / (m · K) or more, more preferably a thermal conductivity of 100 W / (m · K) or more as the material of the metal circuit board 51. On the surface 51S1 of the metal circuit board 51, a thermistor 52 for managing the temperature of the light emitting element 50 is mounted. Further, a connector 53 for supplying a voltage to the light emitting element 50 is mounted on the lower end portion of the surface 51S1 of the metal circuit board 51. Further, the connector 53 is also used for transmitting an electrical signal to the thermistor 51.

  As shown in FIG. 1 and FIG. 2, the present video display device has (1) a (first) radiator 20g for cooling the green light source 10g, and (2) a blue light source 10b and a red light source 10r. (Second) radiator 20br. In the following description, reference numeral “20” is used to indicate each radiator without specifying individual radiators. As clearly shown in FIG. 2, the back surface 51S2 (see FIG. 5) which is the other surface of the metal circuit board 51 of the green light source 10g is heated on one surface (first surface) 20S1 of the first radiator 20g. Connected. Further, the back surface 51S2 of the metal circuit board 51 of each of the blue light source 10b and the red light source 10r is also thermally connected to one surface (first surface) 20S1 of the second radiator 20br.

  The first heat radiator 20g has a substantially square shape when viewed from above the first surface 20S1 on which the light source 10g is mounted. On the other hand, the second heat radiator 20br has a substantially rectangular shape when viewed from above the first surface 20S1 on which the light source 10b and the light source 10r are mounted. As the radiator 20, it is desirable to use a material having high thermal conductivity in order to diffuse heat efficiently. More specifically, a material having a thermal conductivity of 50 W / (m · K) or more, more preferably, a material having a thermal conductivity of 100 W / (m · K) or more is used as the material of the radiator 20. Is desirable.

  As described above, the radiator 20 has a flat surface 20S1 for thermally connecting and installing the corresponding light source 10, and a large number of radiating fins 21 are provided on the back surface or the back surface 20S2. Is formed. With respect to the heat radiating fin 21, it is desirable to form a large number of minute irregularities on the surface of the heat radiating fin 21 in order to increase the heat radiating area.

  As shown in FIG.1 and FIG.2, this image display apparatus has the radiation fin 21 of the 1st heat radiator 20g and this image display apparatus so that the ventilation port faces the heat radiation fin 21 of the 1st heat radiator 20g. An air blower 22 is provided between an air inlet (not shown) provided in the design housing 60 (FIG. 1). In this example, as described above, with respect to the air blower 22, relatively cool outside air around the image display device is taken into the image display device from the intake port and the outside air is directed toward the radiation fins 21. Only the function of rotating only in the direction of blowing is used. Therefore, since the blower 22 always passes the relatively cool outside air toward the inside of the video display device during the operation, the life of the blower 22 is reduced, and the air in the video display device is sucked into the intake air. As compared with the case where the blower 22 is used as a device that discharges to the outside through the mouth, it can be relatively extended. The blower 22 has substantially the same dimensions as the radiator 20g. However, the size of the blower 22 is not limited to this, and the size of the blower 22 may be set larger or smaller than the size of the radiator 20g. More specifically, the blower 22 is an axial fan having a function of blowing air in the direction of the rotation axis. However, the type of the blower 22 is not limited to this, and other types of fans such as a centrifugal fan may be used as the blower 22. The blower 22 includes a lead wire (not shown) for supplying a voltage for driving the blower 22, and a sensor (not shown) for detecting the state of the blower 22 and its abnormality. ing. In addition, in this example, since the existing air blower is used as the air blower 22, detailed description regarding the structure of the air blower 22, etc. is abbreviate | omitted.

  As shown in FIG. 2, the present video display apparatus uses a lens 23 for refracting light emitted from the light source 10 at a predetermined angle for each of the green light source 10g, the blue light source 10b, and the red light source 10r. It is provided one by one. The lens 23 has a function of emitting incident light emitted from the light source 10 corresponding to the lens 23 as substantially parallel light. However, the function of the lens 23 is not limited to the function of emitting as substantially parallel light. For example, the lens group may be formed so that incident light is made substantially parallel light by two or more lenses including the lens 23. It may be configured.

  As the lens 23, it is desirable to use a material having a high transmittance in order to efficiently propagate the light emitted from the corresponding light emitting element 50. More specifically, a material in which the transmittance of light having a main wavelength among the light emitted from the light source 10 is 80% or more, and more preferably 85% or more is used as the material of the lens 23. preferable. In the present embodiment, the shapes of the entrance surface and the exit surface of the lens 23 vary depending on the configuration of the optical system that displays the image. Omitted.

  As shown in FIG. 1, the video display apparatus includes an optical engine 11 and a projection lens 12.

  The optical engine 11 has various optical elements mounted inside the housing of the optical engine 11. More specifically, examples of the mounted optical element include a dichroic mirror, a fly-eye lens, a mirror, a relay lens, and a total reflection prism (all not shown). Further, a display device (not shown) is mounted inside the housing of the optical engine 11. As the display device, a reflective display element is used as an example, in which a large number of minute mirrors are formed and the direction of the light beam is controlled by mechanically controlling the angle of each mirror based on a video signal. . The optical elements are not limited to those listed above, and other various optical elements can be used. Further, the display device or the light valve is not limited to the above-described micromirror device. For example, a reflective display device using liquid crystal or a transmissive display device using liquid crystal may be used. good.

  Further, as illustrated in FIG. 4, the housing of the optical engine 11 includes a mounting opening for mounting the lens 23.

  Next, the arrangement of the constituent members in the video display apparatus according to the present embodiment will be described.

  As shown in FIG. 1, the blue light source 10b and the red light source 10r are arranged so that the directions of the optical axes passing through the centers of the respective light sources are substantially parallel. On the other hand, the green light source 10g is arranged so that the direction of the optical axis passing through the center thereof is substantially orthogonal to the optical axis directions of the blue light source 10b and the red light source 10r. That is, the respective light sources 10g, 10b, and 10r are arranged so as to form an L shape when the light sources are viewed from above the video display device. However, the arrangement of the light sources 10 is not limited to this L-shaped arrangement. For example, the light sources 10 are arranged in a straight line so that the directions of the optical axes passing through the centers of the respective light sources 10 are substantially parallel to each other. You may arrange so that it may line up.

  Regarding the arrangement order of the light sources 10, the light sources 10 are arranged in the order of the green light source 10 g, the blue light source 10 b, and the red light source 10 r when viewed from the position of the blower 22. This arrangement is determined in such an order that the light source 10 having a larger calorific value comes first.

  The light source 10 and the radiator 20 are integrated by being fixed by screwing in a state where each is positioned at a predetermined position. And both surfaces 51S2 (FIG. 5) and 20S1 (FIG. 2) in which the light source 10 and the heat radiator 20 are thermally connected to each other are in a state where a certain pressure is generated by the above screwing. In the thermal connection between the light source 10 and the radiator 20, a material having a high thermal conductivity having fluidity is used to remove an air layer caused by minute irregularities on the surfaces that are thermally connected to each other. It is desirable to mount both 10 and 20 with the intervening. More specifically, it is desirable to use a material having a thermal conductivity of 1 W / (m · K) or more, more preferably a thermal conductivity of 5 W / (m · K) or more, for example, silicon grease. Is used. The radiator 20 is fixed to the housing of the optical engine 11 by screwing.

  The air blower 22 is disposed such that the air outlet side surface faces the heat radiator 20g, and is fixed to the design housing 60 by screwing. The optical engine 11 and the projection lens 12 are also fixed to the design housing 60 by screwing. In addition, although screwing is used as a method of fixing each member, it is not necessarily limited to this fixing method, For example, it is good also as fixing both members by the method of fitting a member and a member. .

  As shown in FIGS. 1 and 4, the radiator 20 and the optical engine 11 have a gap between the radiation fins 21 in the space on the light emitting element 50 side of the light source 10 by the surface 20S1 of the radiator 20 and the side wall of the optical engine 11. An air flow path is formed so that air that has passed through and flows around flows.

  Next, a characteristic operation in the video display apparatus according to the present embodiment will be described.

  FIG. 3 is a diagram schematically showing the flow of air in the video display apparatus of FIG. In FIG. 3, arrows indicate the flow of air. As shown in FIG. 3, when a predetermined voltage is applied to the air blower 22 to drive the air blower 22, the air blower 22 is always from an air inlet (not shown) provided in the design housing 60. Air corresponding to the outside air around the video display device is sucked into the video display device. The air taken in this way first reaches the radiating fin 21 of the radiator 20, passes through the gap between the radiating fins 21, and then branches in two directions. One air flow is a first path that flows toward the radiator 20br, and the other air flow is a second path that flows to a space immediately above the light emitting element 20 of the green light source 10g.

  The air that has reached the first path reaches the radiator 20br, and after passing through the gaps of the radiation fins 21 of the radiator 20br, the image is displayed from an exhaust port (not shown) provided in the design housing 60. It is discharged outside the device. Thus, the first path forms a first air flow path.

  The air reaching the second path first reaches the space immediately above the green light source 10g, and passes through the lens 23, the light emitting element 50 of the green light source 10g, and the periphery of the members 23 and 50. Further, the air passing through the space immediately above the green light source 10g sequentially reaches the space immediately above the blue light source 10b and the space directly above the red light source 10r as a third path. As in the case of the second path, the air flowing through the third path passes through the light emitting element 50 of the blue light source 10b and the lens 23 facing the blue light source 10b, the light emitting element 50 of the red light source 10r, and the lens 23 facing the red light source 10r. , As well as the surrounding areas of these members. Thereafter, the air is discharged to the outside of the video display device through the exhaust port so as to bypass the heat radiator 20br. Thus, the second path and the subsequent third path form a second flow path for air.

  As the air flows as described above, when the air passes through each path, heat exchange occurs between the air and the respective members due to heat transfer, and the air eventually takes away the heat of the members. It is discharged from the exhaust port to the outside of the video display device.

  According to such a configuration, since the space formed between the light emitting element 50 of the light source 10 and the corresponding lens 23 becomes the air flow path, the light emitted from the light emitting element 50 passes through the lens 23. The temperature rise due to the heat generation of the lens 23 can be suppressed, and the temperature rise of the light emitting element 50 can be suppressed. In addition, since the air flow path is also formed on the heat radiating fin 21 side of the radiator 20, the temperature rise of the radiator 20 can be suppressed. As a result, even when a large amount of power is applied to the light source 10 to improve brightness, the lens 23 can be sufficiently cooled and the light emitting element 50 can be sufficiently cooled. In addition, since the deterioration of the material of the lens 23 due to the temperature rise can be reduced, the durability of the lens 23 can be improved. Furthermore, since the cooling efficiency is improved as described above, the amount of air that is flowed by the blower 22 can be reduced, and therefore the noise generated by the blower 22 can be reduced.

  According to the present embodiment, as described above, since the lens 23 can be sufficiently cooled by the air flow, a plastic having a heat resistant temperature lower than that of glass is used as the material of the lens 23. I can do it. In this case, since the lens 23 can be manufactured at a low cost, the cost of the present video display device can be reduced and the weight can be reduced.

  Further, according to the present embodiment, since the lens 23 can be sufficiently cooled, an antireflection film can be formed on the surface of the lens 23. In this case, since the light emitted from the light emitting element 50 can be efficiently propagated while suppressing the reflection at the lens 23, the decrease in the amount of light at the time of propagation can be suppressed. As a result, the display light of this video display device Can be made brighter.

  Further, in the present embodiment, the connector 53 (FIG. 5) (at least a part thereof) of the light source 10 may be disposed in the second flow path. In this case, even when a larger current is supplied from the light source 10, the heat generated by the current can be cooled, and thus the light source 10 can be made brighter by that amount.

(Appendix)
While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

  The present invention is suitable for application to a video display device such as a projector.

It is a disassembled perspective view which shows typically the internal structure of the video display apparatus concerning Embodiment 1 of this invention. It is a disassembled perspective view which shows typically only the main members in the video display apparatus shown in FIG. It is a cross-sectional view which shows typically the flow of the air in the video display apparatus shown in FIG. It is a disassembled perspective view which shows typically the housing | casing and lens of an optical engine of the video display apparatus shown in FIG. It is a schematic perspective view which shows typically the light source used for the video display apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Light source, 10b Blue light source, 10g Green light source, 10r Red light source, 11 Optical engine, 12 Projection lens, 20 Radiator, 21 Radiation fin, 22 Blower, 23 Lens, 50 Light emitting element, 60 Design housing.

Claims (6)

A light source including a light emitting element that emits visible light, a radiator including a radiation fin provided on a back surface facing the surface, and arranged to flow air with respect to the radiator, A blower for flowing air; and a lens for refracting the visible light emitted from the light source,
The light source is thermally connected to the surface of the radiator;
The lens is an image display device arranged so as to form a space between the light source and the lens,
The air that has passed through the gap between the heat dissipating fins of the radiator further includes a flow path for flowing through the space formed between the light source and the lens.
Video display device. The video display device according to claim 1,
When the channel is defined as the second channel,
Until a part of the air taken into the video display device by the blower is exhausted to the outside of the video display device after passing through the gaps of the radiation fins separately from the second flow path. Further comprising a first flow path,
Video display device. The video display device according to claim 1 or 2,
The material of the lens is plastic,
Video display device. The video display device according to any one of claims 1 to 3,
The lens has an antireflection film formed on the surface of the surface facing the light source,
Video display device. The video display device according to any one of claims 1 to 4,
The light source is
A connector for supplying electricity to the light emitting element, provided at an end of the light source;
The connector is at least partially disposed in the flow path,
Video display device. The video display device according to any one of claims 1 to 5,
It further comprises an optical engine equipped with an optical system for displaying images and a display device,
The housing of the optical engine forms the flow path together with the light source, and includes a mounting opening for mounting the lens on the housing.
Video display device.

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