JP2005352023A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device capable of realizing the reduction of noise without increasing the number of parts and without restricting the degree of freedom in design, and made advantageous in terms of realizing miniaturization while restraining cost rising. <P>SOLUTION: The projection type display device 8 is equipped with a rectangular plate-like housing 10, and provided with a cooling fan 30 supplying cooling air to an image forming part 23 inside the housing 10. The cooling fan 30 is attached on the bottom board of the housing 10 through a holder 40. The inlet port 5002 of an air course member 50 is coupled with the blowout port 3004 of the cooling fan 30, and the cooling air passes through the air course member 50 and is supplied to a spot where three liquid crystal panels 20B, 20G and 20R are arranged. The holder 40 is integrally molded by a mold by using synthetic resin having a vibration restraining effect. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display device, and more particularly, to a projection display device with improved silence.

There is a projection display device (projector) that forms an image by projecting a light beam on a screen. Such a projection-type display device emits a light source, an optical system that separates a light beam emitted from the light source into a plurality of light beams having different wavelengths, and combines each separated light beam into one light beam for image formation. An image forming unit, a light source, an optical system, and a housing that houses the image forming unit.
The image forming unit generally includes three liquid crystal panels that respectively display image information of three colors of red (R), green (G), and blue (B) corresponding to each separated light flux. Therefore, these liquid crystal panels are likely to become high temperature due to heat generated from the light flux during driving.
When the liquid crystal panel becomes hot, the liquid crystal panel expands, causing color misregistration and the like, and it becomes difficult to form a clear color image on the screen. Supplying and cooling is performed, and since cooling air is supplied to three locations, a cooling fan having a relatively large capacity is installed in the housing (for example, Patent Document 1).
JP 2002-189250 A

On the other hand, when the cooling fan is driven, since the cooling fan blades rotate at high speed, the cooling fan case vibrates. Since the cooling fan for cooling the image forming unit has a large capacity, vibration is also large. The vibration wave generated by the large vibration propagates to a portion where the cooling fan is fixedly held, and further, the vibration wave is transmitted to the casing (outer shape portion) of the projection display device. There is a problem that the user feels that the vibration propagation between these parts is replaced with noise and that the projection display device itself has noise.
In particular, the projection type display device is often used in a quiet place such as a conference room. Therefore, noise caused by the cooling fan for cooling the image forming unit provided in the housing is seen in the image. Some kind of improvement is desired in order to reduce the noise because it is annoying to humans.
Therefore, in order to reduce the noise of the cooling fan for cooling the image forming unit, it is considered to attach a vibration isolating material to the housing or to support the cooling fan with a new vibration isolating structure using a vibration isolating member. However, the method of attaching a vibration isolating material to the housing increases the number of parts and increases the assembly cost, and is disadvantageous in reducing the size of the apparatus. In addition, in the method of supporting the cooling fan with a new vibration-proof structure, the design freedom is limited due to the internal structure, and the mold of the housing and the holder of the holder that supports the cooling fan must be remade. This increases costs and is disadvantageous in reducing the size of the apparatus.
The present invention has been devised in view of the above circumstances, and an object of the present invention is to reduce noise without increasing the number of parts and without restricting the degree of design freedom, and to suppress an increase in cost. On the other hand, it is an object of the present invention to provide a projection display device that is advantageous in reducing the size of the device.

  In order to achieve the above object, the present invention provides a light source, an optical system for separating a light beam emitted from the light source into a plurality of light beams having different wavelengths, and combining the separated light beams into one light beam for image formation. And a cooling fan that supplies cooling air to the image forming unit, the image forming unit that emits the light, a light source, an optical system, a housing that houses the image forming unit, and a cooling fan that supplies cooling air to the image forming unit. The fan is supported in the housing via a holder, and the holder is integrally formed with a mold using a synthetic resin having a vibration suppressing effect.

  According to the present invention, there is no need for work such as pasting a vibration isolating material to the casing as in the prior art, and there is no need to newly adopt a vibration isolating structure as in the prior art. Noise can be reduced, which is advantageous for reducing the number of parts and assembly costs, and for reducing the size of the projection display device.

The present invention achieves the above object by integrally forming a holder for supporting a cooling fan by a mold using a synthetic resin having a vibration suppressing effect.
Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view of a projection display device showing a cooling fan portion for cooling an image forming unit, and FIG. 2 is an explanatory diagram of a mounting structure of a cooling fan for cooling an image forming unit viewed from the direction of arrow A in FIG. FIG. 3 is an explanatory diagram of a light source, an optical system, and an image forming unit.
The projection display device 8 includes a rectangular plate-shaped casing 10, and inside the casing 10, a light source 12, an illumination optical system 14, a color separation optical system 16, a relay optical system 18, three liquid crystal panels 20, a cross dichroic. A prism 22, a projection lens 24, a cooling fan 30, an air path member 50, and the like are provided. The cooling fan 30 is for cooling the image forming unit, and other fans are also provided for cooling the light source 12, but the present invention is applied to the mounting structure of the cooling fan 30 for cooling the image forming unit. ing.
White light emitted from the light source 12 is guided to the color separation optical system 16 and the relay optical system 18 by the illumination optical system 14, and red (R), green (G), and blue by the color separation optical system 16 and the relay optical system 18. (B) are separated into three color light fluxes, and the three color light fluxes correspond to the three liquid crystal panels 20 (3) for displaying the corresponding three color image information of red (R), green (G), and blue (B), respectively. 20R, 20G, and 20B), and then combined into one light beam by the cross dichroic prism 22 and projected as a color image on the screen via the projection lens 24.
In the present embodiment, an image forming unit 23 is configured including three liquid crystal panels 20 and a cross dichroic prism 22.

More specifically, as shown in FIG. 3, the illumination optical system 14 includes a concave lens 1402, a UV cut filter 1404, first and second fly-eye lenses 1406 and 1408, a PS conversion element 1410, and a condenser lens 1412 in this order. The light beams from the light source 12 pass through these and enter the color separation optical system 16.
The color separation optical system 16 includes a blue dichroic mirror 1602 that reflects a blue light beam and transmits green and red light beams, and a red dichroic mirror 1604 that reflects a green light beam and transmits a red light beam. doing.
Of the light beams emitted from the illumination optical system 14, when the blue light beam is reflected by the dichroic mirror 1602, it passes through the liquid crystal panel 20 </ b> B via the UV absorption filter 1606, the total reflection mirror 1608, and the condenser lens 1610, and the cross dichroic prism 22. To.

Of the light beams transmitted through the blue dichroic mirror 1602, when the green light beam is reflected by the red dichroic mirror 1604, it passes through the liquid crystal panel 20 G via the condenser lens 1610 and reaches the cross dichroic prism 22.
Of the light beams that have passed through the blue dichroic mirror 1602, when the red light beam passes through the red dichroic mirror 1604, the first relay lens 1802, the total reflection mirror 1804, and the second relay lens 1806 that constitute the relay optical system 18. The total reflection mirror 1808 passes through the liquid crystal panel 20R via the condenser lens 1610 and reaches the cross dichroic prism 22.
Each of the three liquid crystal panels 20B, 20G, and 20R is provided with an incident side polarizing plate 2002 on the light beam incident side, and an output side polarizing plate 2004 on the light beam output side.

In the cross dichroic prism 22, a dielectric multilayer film 22B that reflects a blue light beam and a dielectric multilayer film 22R that reflects a red light beam are formed in an approximately X shape along the interface of four right-angle prisms. Yes. The cross dichroic prism 22 has three incident surfaces that face each of the emission sides of the liquid crystal panels 20B, 20G, and 20R and that are orthogonal to the optical axis, and one emission surface that faces the projection lens 24 and is orthogonal to the optical axis. 2202.
The blue light beam incident on the cross dichroic prism 22 from the liquid crystal panel 20B corresponding to the blue light beam is reflected by the dielectric multilayer film 22B, emitted from the emission surface 2202, and reaches the projection lens 24.
The red light beam incident on the cross dichroic prism 22 from the liquid crystal panel 20R corresponding to the red light beam is reflected by the dielectric multilayer film 22R, emitted from the emission surface 2202, and reaches the projection lens 24.
The green light beam incident on the cross dichroic prism 22 from the liquid crystal panel 20G corresponding to the green light beam passes through the dielectric multilayer film 22B and the dielectric multilayer film 22R, is emitted from the emission surface 2202, and reaches the projection lens 24.
Accordingly, a light beam obtained by combining three light beams of blue, red, and green is incident on the projection lens 24 from the exit surface 2202 of the cross dichroic prism 22, and the light beam guided by the projection lens 24 is imaged on the screen. As a result, a color image is formed.
The configurations and layouts of the illumination optical system 14, the color separation optical system 16, the relay optical system 18, and the image forming unit 23 are not limited to the above-described embodiments, and various conventionally known structures can be applied.

The cooling fan 30 is a sirocco fan, and includes a case 3002, a blade disposed rotatably in the case 3002, a motor, and the like. A suction port is provided on the bottom surface of the case 3002, and the case 3002 side A blowing port 3004 is provided in the part.
The cooling fan 30 is mounted on the bottom plate of the housing 10 via a holder 40.
In this embodiment, the holder 40 has a flat plate shape. A mounting seat (mounting portion) 4002 for mounting the case 3002 of the cooling fan 30 bulges on the upper surface of the holder 40, and the holder 40 is mounted on the lower surface. An attachment seat (attachment portion) 4004 for attaching to the bottom plate of the housing 10 is formed to bulge.
The cooling fan 30 is attached to the holder 40 by a screw that is screwed into the screw hole on the bottom surface of the case 3002 from the lower surface of the holder 40 through the screw insertion hole of the mounting seat 4002, and the holder to which the cooling fan 30 is attached. 40 is attached to the bottom plate of the housing 10 by screws that are screwed into the screw holes of the mounting seat 4004 through the screw insertion holes of the bottom plate of the housing 10.
An air intake port is provided at the position of the holder 40 facing the suction port on the bottom surface of the case 3002 and the bottom plate portion of the housing 10, and the air outside the housing 10 sucked from the suction port on the bottom surface of the case 3002 It is configured to blow out to the image forming unit 23 through the road member 50.

The air passage member 50 is made of a synthetic resin and is integrally formed in a hollow shape using a mold. The air passage member 50 is disposed below the image forming unit 23 inside the housing 10 and is bulged and formed on the bottom surface of the air passage member 50. A screw inserted from the bottom plate of the housing 10 is fixed to the seat by screwing.
The air passage member 50 has an air inlet 5002 connected to the air outlet 3004 of the cooling fan 30, and the air passage member has air outlets 5004 that are opened below the three liquid crystal panels 20B, 20G, and 20R. The cooling air is supplied from the three outlets 5004 to the place where the three liquid crystal panels 20B, 20G, and 20R are arranged.
In the present embodiment, the cooling air outside the housing 10 taken into the housing 10 is guided to the outside of the housing 10 by an exhaust fan that is disposed in the vicinity of the light source 12 and cools the light source 12. It is configured.

In the above configuration, the holder 40 that supports the cooling fan 30 in the housing 10 is integrally formed with a mold using a synthetic resin having a vibration suppressing effect.
A commercial item can be used as such a synthetic resin, for example, CRN7830 of the brand name "Juranek" of Wintech Polymer Co., Ltd. can be used.

The experimental results of vibration and noise according to this example are shown in FIGS.
FIG. 4 (A) shows the vibration strength (magnitude) of the casing 10 in each frequency band when the cooling fan 30 is supported using the holder 40 of the embodiment, and FIG. 4 (B). Is a measurement of the strength (magnitude) of vibration of the casing 10 in each frequency band when the cooling fan 30 is supported using a normal synthetic resin (ABS resin) that does not have a vibration suppressing effect. .
As is clear from FIGS. 4A and 4B, although both have peaks near 300 Hz, the vibration effective value is lower overall when the holder 40 of the embodiment is used. I understand.
A curve (A) in FIG. 5 is obtained by connecting measured values of noise in each frequency band when the cooling fan 30 is supported using the holder 40 of the embodiment, and a curve (B) in FIG. The measured values of noise in each frequency band when the cooling fan 30 is supported using a normal synthetic resin (ABS resin) having no effect are connected.
As is clear from the curves (A) and (B) in FIG. 5, it can be seen that both are lower when the holder 40 of the embodiment is used in the entire frequency range.

Therefore, according to the present embodiment, the noise of the projection display device 8 can be reduced without requiring a work such as pasting a vibration isolating material on the housing 10 as in the prior art, the number of parts can be reduced, and the assembly cost can be reduced. This is advantageous for reducing the size of the projection display device 8.
Further, it is not necessary to newly adopt a vibration-proof structure as in the prior art, and therefore, the problem that the degree of design freedom is restricted due to the internal structure is eliminated, which is advantageous in reducing the cost.
Further, since it is sufficient to simply change the synthetic resin to be used, the existing mold can be used as it is without the need to remake the mold, which is further advantageous in reducing the cost.

In the present embodiment, the suction port 5002 of the air passage member 50 is connected to the outlet 3004 of the cooling fan 30, and the vibration of the cooling fan 30 is not limited to the holder 40 but also from the suction port 5002 to the air passage member 50. Propagated.
Therefore, in the embodiment, a case has been described in which the holder 40 is integrally formed with a mold using a synthetic resin having a vibration suppressing effect. However, the air passage member 50 together with the holder 40 is a mold using a synthetic resin having a vibration suppressing effect. If the integral molding is performed, the noise of the projection display device 8 is further reduced.

It is a schematic perspective view of a projection type display device showing a cooling fan part for cooling an image forming unit. It is explanatory drawing of the attachment structure of the cooling fan for image formation part cooling seen from A arrow direction of FIG. It is explanatory drawing of a light source, an optical system, and an image formation part. It is a measurement result of the intensity | strength (size) of the vibration of the housing | casing in each frequency band in the case of supporting a cooling fan using the holder of an Example, and the case of a prior art example. It is the measurement result of the noise in each frequency band in the case of supporting a cooling fan using the holder of an example, and the case of a conventional example.

Explanation of symbols

  8: Projection type display device, 10: Housing, 12: Light source, 20: Liquid crystal panel, 30: Cooling fan, 40: Holder, 50: Airway member

Claims (2)

A light source;
An optical system for separating a light beam emitted from the light source into a plurality of light beams having different wavelengths;
An image forming unit configured to synthesize and emit the separated light beams into one light beam for image formation;
A housing for housing the light source, optical system, and image forming means;
A cooling fan for supplying cooling air to the image forming unit;
A projection display device comprising:
The cooling fan is supported in the housing via a holder,
The holder is integrally formed with a mold using a synthetic resin having a vibration suppressing effect.
A projection type display device characterized by that.   A hollow air passage member that guides cooling air to the image forming unit is connected to the outlet of the cooling fan, and the air passage member is integrally formed with a mold using a synthetic resin having a vibration suppressing effect. The projection type display device according to claim 1.

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