JP2002214695A - Lamp house - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorption structure by which the noise of equipment and device equipped with a lamp and a fan for cooling a high temperature part heated by the lamp is lowered and which does not newly require a installation place. SOLUTION: The housing 1 of the lamp house for housing lamp 2 is formed in aw double wall shape by an internal wall 7 and an external wall 8 forming air gap between it 9 and the wall 7 in between, and holes 10 are formed on the wall 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp house provided in a projection type image display device or the like.

[0002]

2. Description of the Related Art A liquid crystal projector as a general projection type image display device condenses light emitted from a light source on a liquid crystal panel via a mirror or the like, and projects an image on the liquid crystal panel on a screen through a projection lens. Things. Liquid crystal projectors include a front type in which a screen and a device main body are separated, and a rear projection type in which a screen, a liquid crystal group, a light source, a mirror, and the like are integrally formed and image light passes through the screen. In the case of the front type, the light of the lamp of the light source is color-separated by the color separation mirror, the three colors R, G, and B are transmitted through the liquid crystal panel, and the colors are synthesized by the color synthesis mirror and enlarged and projected by the projection lens. Is common.

[0003] The lamp is driven at a high pressure in order to increase the brightness of the light source, and the temperature near the light source unit becomes high at about 200 to 300 ° C. Generally, a metal halide lamp or a high-pressure mercury lamp is used.
Since the luminance drops to about half in about time, it is often housed in a replaceable box-shaped housing (lamp house). In addition, a cooling fan is used to cool the high-temperature portion in the vicinity of the light source unit described above, and sends a cool air in a certain direction to the concave mirror attached to the lamp and the periphery thereof so that hot air escapes outside the device. .

[0004]

In recent years, as the above-mentioned liquid crystal projectors have been downsized and the brightness has been increased, the amount of heat generated has increased and a high cooling capacity has been required. For this reason, it is necessary to provide a plurality of fans for cooling lamps, power supply units, and the like, or to increase the number of rotations of the fans, and the noise of the liquid crystal projector is increasing. In addition, as miniaturization progresses, it is difficult to secure a new place for installing a sound absorbing material or the like for preventing noise, and it is difficult to take measures against noise.

As described above, in recent projection type image display devices such as liquid crystal projectors, it is required to enhance the sound absorbing effect without taking a place for installing a sound absorbing structure. Note that such a problem is not limited to a projection-type image display device such as a liquid crystal projector, but exists for a general device including a lamp and a fan for cooling a high-temperature portion heated by the lamp. I do.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to reduce the noise of equipment having a lamp and a fan for cooling a high-temperature portion heated by the lamp. It is an object of the present invention to provide a sound absorbing structure which can be lowered and does not require a new place for installation.

[0007]

According to a first aspect of the present invention, there is provided an apparatus provided with a lamp and a fan for cooling a high-temperature portion heated by the lamp. A lamp house for accommodating the lamp, characterized by comprising a member having a sound absorbing effect.

According to a second aspect of the present invention, in the first aspect, the member having the sound absorbing effect is a double wall having an inner wall and an outer wall forming a gap between the inner wall and the inner wall. It is characterized by:

According to a third aspect, in the second aspect, a hole is provided in the inner wall.

A fourth invention is characterized in that, in the second or third invention, a sound absorbing material is provided in the gap.

According to a fifth aspect of the present invention, in the first aspect, the member having the sound absorbing effect comprises a housing and a sound absorbing material provided on the housing.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a lamp house according to a first embodiment of the present invention.

This lamp house is mounted on an image display device such as a liquid crystal projector, and has a substantially rectangular parallelepiped housing 1 formed in a double-walled shape. 2 are stored. This lamp house is attached to and detached from the image display device together with the lamp 2. The housing 1 has an opening 3 for taking in cooling air at a lower portion of one side surface, and has an opening 4 for discharging the air at an upper portion of the side surface opposite to the side surface. are doing. The arrows indicate the flow direction of the cooling air. That is, the cooling air flows into the housing 1 from the opening 3 and cools the lamp reflector 5 and the lamp neck 6, and then cools the opening 4.
From the housing 1.

The housing 1 is a double wall having an inner wall 7 and an outer wall 8 forming a gap 9 between the inner wall 7. The inner wall 7 is provided with a plurality of tubular holes 10. ing. Note that the outer wall 8 is formed in a flat plate shape. With such a double-walled structure, the air in the hole 10 vibrates according to the frequency of the sound, whereby the air layer behind in the gap 9 between the inner wall 7 and the outer wall 8 vibrates. At this time, energy is lost due to friction between the vibrating air and the pipe wall of the hole 10, and the sound is absorbed. This vibration has a certain resonance frequency, which is the same as when the back air layer is vibrating as a spring and the air in the portion of the hole 10 as an object having mass.

For example, the thickness of the plate material forming the housing 1 is t (1 mm), the diameter of the hole 10 is d (20 mm), the distance between the centers of the holes 10 is D (30 mm), the thickness of the back air layer, That is, the distance between the inner wall 7 and the outer wall 8 is L (10 mm),
Assuming that the sound speed is C, the resonance frequency f ₀ is calculated by the equation in FIG. The numerical values in parentheses indicate the values in the present embodiment, and the sound speed is assumed to be 340 m / s.

When a sound having a frequency coincident with the resonance frequency f ₀ enters the hole 10, the vibration of the air in the hole 10 increases, the energy loss increases, and the sound is absorbed. In general, the sound absorption characteristic of such a structure has a mountain shape with the resonance frequency at the center. Therefore, designing the frequency of sound generated within the housing of the image display apparatus resonance frequency f ₀ is equal way the inner wall 7, an outer wall 8, a hole 10.

The sound generated in the image display device includes wind noise of an exhaust fan or the like for discharging heat generated in the image display device to the outside, turbulence caused by rotating blades, and bending of a flow path through which air passes. Many are caused by turbulence generated by rapid enlargement and contraction of portions and flow paths, and the generated sound propagates into the housing of the image display device and resonates to increase. Therefore, it is very effective to absorb the sound in the propagation path of the sound generated by the exhaust fan, that is, in the flow path of the air flowing in the image display device.

The lamp house of the present invention has a sound absorbing effect. The lamp house is provided in a flow path of cooling air and absorbs sound generated by an exhaust fan or the like and propagated in the lamp house. The sound absorbing effect is very high, and the noise generated in the ventilation path can be absorbed without lowering the performance of cooling the lamp. Further, since the housing has a sound absorbing structure, it is not necessary to newly provide a place for sound absorption. Further, since the housing has a simple structure of a double wall composed of a flat plate and a perforated plate, it is easy to manufacture and has a high sound absorbing effect.

Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic sectional view of a lamp house according to a second embodiment of the present invention. In the following embodiments, portions corresponding to those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

In this lamp house, a sound absorbing material 11 is provided in the space 9. As the sound absorbing material 11, for example, a porous material such as glass wool or rock wool can be used. FIG. 4 shows that the opening ratio of the inner wall 7 is 0.03 to 0.20,
The relationship between (sound frequency / resonance frequency) and the sound absorption coefficient when the distance between the inner wall 7 and the outer wall 8 is set to 30 to 300 mm is shown. (A) does not provide anything in the space 9 (ie,
In the case where only the air layer exists), (b) is a case where glass wool is provided in the gap 9. According to this figure, it can be seen that the provision of the sound absorbing material 11 doubles the sound absorption coefficient in the resonance frequency band. By providing the sound absorbing material in the gap between the double walls, the sound absorbing effect can be further enhanced.

Next, a third embodiment of the present invention will be described. FIG. 5 is a schematic sectional view of a lamp house according to a third embodiment of the present invention.

In this lamp house, the housing 1 comprises only the outer wall 8 and the sound absorbing material 11 is adhered to the inner surface thereof, and the lamp 2 is installed inside the sound absorbing material 11. The sound absorbing material 11 is formed of a porous material such as glass wool or a foamed resin material, and the outer wall 8 is formed so as not to block the flow path of the air passing through the lamp house.
Is affixed to the inside of By doing this,
The sound transmitted in the image display device can be absorbed by the sound absorbing material 11 without obstructing the flow of air passing through the lamp house.

Next, a fourth embodiment of the present invention will be described. FIG. 6 is a schematic sectional view of a lamp house according to a fourth embodiment of the present invention.

In this lamp house, the housing 1 has a double wall shape, and a gap 9 between the inner wall 7 and the outer wall 8 is filled with air. The inner wall 7 is made of a thin plate and can be bent. In this case, the inner wall 7 functions as a mass and the gap 9 functions as a spring, and forms a vibration system having a resonance frequency. When the sound of the resonance frequency propagates in the lamp house, the inner wall 7 resonates and vibrates, and energy loss near the resonance frequency increases due to internal friction of the inner wall 7 itself and friction near a portion where the inner wall 7 is attached to another member. Sound is absorbed. In general, the sound absorption characteristics due to such a structure are mountain-shaped sound absorption characteristics centered on the resonance frequency. Therefore, the housing 1 is designed so that the resonance frequency becomes the frequency of the sound generated in the housing, and the sound is absorbed.

Next, a fifth embodiment of the present invention will be described. FIG. 7 is a schematic sectional view of a lamp house according to a fifth embodiment of the present invention.

In this lamp house, a part of a space 9 between an inner wall 7 and an outer wall 8 of a housing 1 formed in the same manner as in the fourth embodiment is provided with a porous sound absorbing material 1 such as glass wool.
1 is provided. Since the sound absorbing material 11 can absorb a wide range of sound propagated in the lamp house, a higher sound absorbing effect can be obtained in addition to the sound absorbing effect described in the fourth embodiment. In the present embodiment, the sound absorbing material 11 is provided in a part of the space 9, but the sound absorbing material 11 may be filled in the entire space 9.

The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described embodiment without departing from the gist of the present invention.

[0028]

As described above, the lamp house of the present invention is provided with the member having the sound absorbing effect, so that the noise generated inside the equipment using the high-intensity lamp such as the projection type image display device can be reduced. Can absorb sound. Further, it is not necessary to newly provide a place for installing the sound absorbing structure in the housing part outside the lamp house.

Further, the lamp house of the second invention is manufactured by the fact that the member having the sound absorbing effect is a double-walled structure comprising an inner wall and an outer wall forming a gap between the inner wall and the inner wall. Is easy and low cost.

In the lamp house according to the third aspect of the present invention, the hole is provided in the inner wall of the double wall, so that the sound absorbing effect is higher.

Further, in the lamp house according to the fourth aspect of the invention, the sound absorbing material is provided in the space between the inner wall and the outer wall.
Higher sound absorption effect.

In the lamp house according to the fifth aspect of the present invention, since the member having the sound absorbing effect is composed of the housing and the sound absorbing material provided on the housing, the lamp house is easy to manufacture and has a high sound absorbing effect.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a lamp house according to a first embodiment of the present invention.

FIG. 2 is a formula for calculating a resonance frequency of air in a hole 10 provided in an inner wall 7;

FIG. 3 is a schematic sectional view of a lamp house according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between (sound frequency / resonance frequency) and sound absorption coefficient.

FIG. 5 is a schematic sectional view of a lamp house according to a third embodiment of the present invention.

FIG. 6 is a schematic sectional view of a lamp house according to a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view of a lamp house according to a fifth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 housing 2 lamp 7 inner wall 8 outer wall 9 gap 10 hole 11 sound absorbing material

Claims (5)

[Claims] 1. A lamp house, which is provided in a device having a lamp and a fan for cooling a high-temperature portion heated by the lamp, and stores the lamp, comprising a member having a sound absorbing effect. Lamp house characterized by that. 2. The member having the sound absorbing effect comprises: an inner wall;
2. The lamp house according to claim 1, wherein the lamp house has a double wall shape including an outer wall forming a gap between the inner wall and the inner wall. 3. The lamp house according to claim 2, wherein a hole is provided in the inner wall. 4. The lamp house according to claim 2, wherein a sound absorbing material is provided in the space. 5. The lamp house according to claim 1, wherein the member having the sound absorbing effect includes a housing and a sound absorbing material provided on the housing.