Projector with hermetic housing and air guide wall therein

A projector includes a light modulation device; a projection lens; a hermetic housing; a projector housing containing the hermetic housing; a heat exchanger; an air guide wall being located in the hermetic housing and partitioning the air guide passage from a main space containing the light modulation device, the air guide wall including: a communication part adjoining the heat exchanger and providing communication between the air guide passage and the main space, and an opening functioning as an inlet for guiding air from the main space into the air guide passage after the air has passed through the heat exchanger; and a fan located at the inlet so as to introduce the air in the main space into the air guide passage, to guide the air in the air guide passage to the communication part, and to blow the air from the communication part to the heat exchanger.

BACKGROUND

1. Technical Field

The present disclosure relates to a projector.

2. Description of Related Art

Projectors have been used in concert venues, outdoor facilities, and other various locations. Such projectors are expected to be protected from dust so as to prevent image degradation even when used in large spaces. For example, Japanese Unexamined Patent Application Publication No. 2016-218383 discloses a projector shielded from dust by housing a light modulation device in a hermetic housing.

When the light modulation device is housed in the hermetic housing, the heat generated by the light modulation device may be trapped in the housing, thereby having harmful effects. To avoid this problem, the above-mentioned patent literature circulates the air inside the hermetic housing using a circulation fan, thereby cooling and radiating the light modulation device. However, this patent literature has not made a detailed analysis of air circulation channels, and thus has room for improvement in radiation performance.

The present disclosure provides a projector that is dust-proof and has better radiation performance.

SUMMARY

The projector according to the present disclosure includes a light modulation device, a projection lens, a hermetic housing, a projector housing, a heat absorption part, an air guide wall, and a first sirocco fan. The projection lens is configured to project light received from the light modulation device. The hermetic housing hermetically houses the light modulation device. The projector housing contains the hermetic housing. The heat absorption part is located at the upper section of the hermetic housing and is configured to absorb heat from the hermetic housing and to radiate the heat to the outside of the hermetic housing. The air guide wall is located in the hermetic housing and partitions an air guide passage, which extends along the bottom surface of the hermetic housing, from a main space containing the light modulation device. The air guide wall includes a communication part and an opening. The communication part adjoins the heat absorption part and provides communication between the air guide passage and the main space. The opening functions as an inlet for guiding air from the main space into the air guide passage after the air has passed through the heat absorption part. The first sirocco fan is located at the inlet and is configured to introduce the air in the main space into the air guide passage, to guide the air in the air guide passage to the communication part, and to blow the air from the communication part to the heat absorption part.

According to the present disclosure, the projector is rendered dust-proof by housing the light modulation device in the hermetic housing. The projector also has better radiation performance by locating the air guide passage along the bottom surface of the hermetic housing so as to achieve more efficient heat release from the bottom surface of the hermetic housing.

DETAILED DESCRIPTION

An embodiment will now be described in detail with reference to the accompanying drawings whenever necessary. However, unnecessarily detailed descriptions may be omitted. For example, well-known matter and substantially the same configuration as described earlier may not be described repeatedly to avoid redundancy and to help those skilled in the art understand them easily. The inventers have provided the accompanying drawings and the following description to make those skilled in the art fully understand the present disclosure, and do not intend to limit the claimed subject matter.

First Exemplary Embodiment

FIG. 1is an external perspective view of projector1according to an embodiment of the present disclosure. Projector1forms an optical image by modulating the light beams emitted from an internal light source based on image information, and projects the formed optical image on a screen in an enlarged scale. Projector1includes substantially rectangular parallelepiped projector housing10and projection lens20exposed from projector housing10. Projector housing10has a bottom surface with substantially columnar legs11at its four corners. Projector1stands on legs11. Projection lens20has an optical axis L, and for convenience of explanation, the direction (arrow A) in which light is projected is referred to as the front, and the opposite direction (arrow B) is referred to as the back.

Projection lens20, which consists of a set of lenses housed in a lens barrel, projects an optical image in an enlarged scale. The optical image is modulated based on the image information by the body of projector1. In the present embodiment, projection lens20is detachable from projector housing10. Lens20can be replaced to change the magnification factor depending on the purpose of use.

Projector housing10includes front panel12with hole12ato pass projection lens20, and rear panel13on the opposite side of housing10from front panel12. Housing10further includes lower panel14having four legs11(two of which are shown), upper panel15on the opposite side of housing10from lower panel14, and two side panels16and17coupling lower panel14and upper panel15together. These panels12-17, all of which are made of synthetic resin, are combined as shown in the drawings and screwed together to form rectangular parallelepiped housing10. Housing10has as a characteristic a plurality of cooling holes18through which the heat in housing10can be released outside.

FIG. 2is an internal perspective view of projector housing10shown inFIG. 1. InFIG. 2, upper panel15and projection lens20have been removed from projector1. Projector housing10contains optical unit100mechanically coupled with projection lens20, a light source unit (not shown) for supplying light to optical unit100, a power supply unit (not shown) for suppling power to optical unit100and the light source unit, and control device30(seeFIG. 10) for taking control of these components.

FIG. 3is a perspective view of optical unit100shown inFIG. 2. Optical unit100is sealed with hermetic housing110. Housing110, which is substantially rectangular parallelepiped, includes bottom mount case111, top mount case112, fan case113, and heat exchanger case114.

Bottom mount case111contains main optical components of optical unit100and also forms the front face of optical unit100. The front face has circular lens-mounting hole111ainto which projection lens20(seeFIG. 1) is inserted. When inserted in hole111a, lens20completely closes hole111a, allowing hermetic housing110to be a sealed space. The front face also has, near lens-mounting hole111a, button111bfor removing lens20. The user can press button111bto easily remove lens20from optical unit100.

Top mount case112is assembled above bottom mount case111and forms the lid of bottom mount case111.

Fan case113is assembled on the lateral side of bottom mount case111so as to house sirocco fans160and161(seeFIG. 8), which will be described later.

Heat exchanger case114is assembled above fan case113and on the lateral side of top mount case112so as to house heat exchanger170.

Fan case113and heat exchanger case114define the air circulation channel. To be more specific, the internal space of fan case113and heat exchanger case114is fluidically communicated with the space defined by bottom mount case111and top mount case112. The bottom of each of bottom mount case111and fan case113has an opening. As shown inFIG. 2, when optical unit100is placed on lower panel14, these openings are closed by lower panel14. In other words, projector housing10and hermetic housing110share the bottom surface.

FIGS. 4 and 5are internal perspective views of hermetic housing110shown inFIG. 2. To be more specific,FIG. 4is an internal perspective view of hermetic housing110seen from the front after top mount case112is detached.FIG. 5is an internal perspective view of hermetic housing110seen from the back after top mount case112is detached. As seen inFIGS. 4 and 5, bottom mount case111contains light-incident part120, light modulation device130, and sirocco fans (third sirocco fans)140-142. Light modulation device130includes digital mirror devices (DMDs), which are light modulation devices based on digital light processing (DLP) (registered trademark) technology. In the present embodiment, the light modulation is based on DLP technology. The optical mechanism of DLP projectors is well known so that its detailed description and illustration may be omitted in the following description.

Light-incident part120guides the light from the light source unit (not shown) to light modulation device130. Light-incident part120includes light collection part121having an opening with a lens for collecting the light from the light source unit (not shown), and light guide part122composed of a lens barrel, mirrors, and other parts which guide the light received from light collection part121to light modulation device130.

Light modulation device130modulates the light from light-incident part120based on image information so as to form a desired optical image. Light modulation device130includes DMDs131-133corresponding to red, green, and blue, respectively, as modulation colors. Light modulation device130further includes prism134for guiding the light from light-incident part120to DMDs131-133by splitting the light into predetermined wavelength ranges corresponding to DMDs131-133. Prism134also guides the light modulated by DMDs131-133to projection lens20.

The desired optical image formed by the light modulation of DMDs131-133passes through projection lens20(seeFIG. 1) and is projected on a screen or other similar devices in an enlarged scale. DMDs131-133generate heat because of their function, or in other words, DMDs131-133are heating elements. In the present embodiment, sirocco fans140-142are oriented to DMDs131-133so as to cool them. Sirocco fans140-142are screwed into hermetic housing110via fixing plate143.

FIG. 6is a partially exploded view of hermetic housing110and lower panel14shown inFIG. 2, which are aligned with each other. InFIG. 6, hermetic housing110and projector housing10are in an exploded state. Bottom mount case111includes air guide wall115as its false bottom. Air guide wall115partitions the sealed space of hermetic housing110into two regions although not completely. To be more specific, hermetic housing110is partitioned into a main space S1and an air guide passage S2. The main space S1contains light modulation device130as a heating element and other main optical components. The air guide passage S2is located below the main space S1and functions as a radiating air passage (seeFIGS. 9 and 11). In the present embodiment, the sealed space in hermetic housing110is partitioned into two regions, but can alternatively be partitioned into three or more regions. The main space S1is defined by bottom mount case111, top mount case112, and air guide wall115. The air guide passage S2is defined by bottom mount case111, lower panel14, fan case113, heat exchanger case114, and air guide wall115as will be described later. In order to form the air guide passage S2, lower panel14has recess14ashaped in conformance with bottom mount case111, and curved surface14bfor directing airflow upward. Thus, the air guide passage S2in the present embodiment is curved in an L shape. Air guide wall115has two circular openings115awhich provide fluidic communication between the main space S1and the air guide passage S2. Openings115aare formed as the inlet of the air guide passage S2in terms of airflow. The inlet is located near the lateral part on the opposite side of bottom mount case111from the lateral part adjoining heat exchanger case114when seen from the front. The inlet is equipped with the air inlet port of two sirocco fans150and151(first sirocco fans), so that sirocco fans150and151introduce the air in the main space S1into the air guide passage S2. Sirocco fans150and151then guide the air in the passage S2to communication part115b(seeFIG. 9), which will be described later. InFIG. 6, sirocco fans150and151are placed on lower panel14for easier explanation of openings115a. In fact, however, sirocco fans150and151are screwed into air guide wall115.

FIG. 7is a front view of optical unit100.FIG. 8is a perspective view of unit100seen from below.FIG. 9is a sectional view of unit100seen from the front. In the sectional view ofFIG. 9, for a better understanding of the drawing, air guide wall115alone are shown with a hatch pattern, and the other components are not hatched. As seen inFIGS. 7 to 9, two sirocco fans150and151(first sirocco fans) are located below air guide wall115. Air guide wall115extends along the bottom surface of hermetic housing110and also extends to heat exchanger (heat absorption part)170housed in heat exchanger case114. Thus, air guide wall115is formed in an L shape. As a result, air guide passage S2is also formed in an L shape. Air guide wall115includes communication part115badjoining heat exchanger170and providing communication between the air guide passage S2and the main space S1. Communication part115bis oriented to heat exchanger170. In other words, communication part115bis the outlet of the air guide passage S2. In the communication part115bfunctioning as the outlet, two sirocco fans160and161(second sirocco fans) housed in fan case113are oriented to heat exchanger170. The air in the air guide passage S2is blown by sirocco fans150-151and160-161to heat exchanger170through communication part115b.

As shown inFIG. 5, heat exchanger170includes a plurality of rectangular plate fins171made of metal and arranged in parallel, and a plurality of liquid-cooling pipes172penetrating the middle portions of fins171. In heat exchanger170, a liquid refrigerant is circulated through liquid-cooling pipes172. The refrigerant running through liquid-cooling pipes172cools the air that is passing through fins171. Heat exchanger170is located partly inside and partly outside hermetic housing110. As a result, the heat in hermetic housing110is absorbed by the part of heat exchanger170that is located inside housing110. The absorbed heat is conveyed through heat exchanger170and is radiated from the part of heat exchanger170that is exposed from housing110.

When seen along the optical axis L of projection lens20(seeFIG. 1) as shown inFIG. 9, sirocco fans150and151are located opposite to heat exchanger170with respect to light modulation device130(i.e., the heating element). This arrangement forms the air circulation system shown by the arrow inFIG. 9, which will be described later. In other words, the air in hermetic housing110guided by sirocco fans150and151is circulated around the optical axis L.

In the present embodiment, control device30takes control of sirocco fans140-142,150-151, and160-161. Control device30is composed of hardware including a central processing unit (CPU) and storage devices such as random access memory (RAM) and read only memory (ROM), and software run on the hardware.

FIG. 10is a block diagram of the control of control device30. As conceptually shown inFIG. 10, projector1includes detection part31for detecting the attachment state of projection lens20. Detection part31is a sensor for detecting the attachment state of projection lens20mechanically or electrically. Control device30includes determination part32and fan-stop part33. Determination part32determines whether or not the attachment state detected by detection part31indicates that projection lens20is in a detached state. Fan-stop part33stops sirocco fans140-142,150-151, and160-161when determination part32has determined that projection lens20is in a detached state. This configuration allows projector1to stop sirocco fans140-142,150-151, and160-161whenever necessary so as to be dust-proof as will be described later.

The operation of projector1structured as above will be described as follows. Note that the projecting operation of projector1is the same as that of general DLP projectors, and thus its description will be omitted. The following description will be focused on the radiating and controlling operations of projector1.

FIG. 11is a schematic diagram of the structure shown inFIG. 9. With reference toFIGS. 9 and 11together, the flow of air (see the arrows) will be described as follows. Air is introduced by sirocco fans150and151from the main space S1into the air guide passage S2through openings115afunctioning the inlet of the air guide passage S2. The air introduced to air guide passage S2is guided by sirocco fans150-151and160-161from the inlet toward communication part115bfunctioning as the outlet. The air guided to the outlet is blown by sirocco fans150-151and160-161to heat exchanger170, passes through heat exchanger170and the vicinity of light modulation device130(the heating element), and returns to openings115a. In this manner, in hermetic housing110of projector1according to the present embodiment, air is circulated around the optical axis L.

The present embodiment adopts sirocco fans because they have sufficient static pressure to circulate air inside the sealed space of hermetic housing110. As long as this condition is satisfied, sirocco fans140-142used to directly cool DMDs131-133can be made more compact and lower in static pressure than sirocco fans150-151and160-161used for air circulation. Sirocco fans150-151and160-161used for air circulation do not have to be different in static pressures from each other and can be identical fans.

2-2. Controlling Operation

As shown inFIG. 10, projector1according to the present embodiment allows detection part31to detect the attachment state of projection lens20. Upon receiving information from detection part31, projector1allows determination part32of control device30to determine whether projection lens20is in the detached state. If lens20is determined to be in the detached state, fan-stop part33of control device30stops sirocco fans140-142,150-151, and160-161. This configuration prevents sirocco fans140-142,150-151, and160-161from drawing dust into hermetic housing110when lens20is detached. Although it is preferable to stop all of sirocco fans140-142,150-151, and160-161as in the present embodiment, it is alternatively possible to stop only some of them.

As described so far, projector1according to the present embodiment includes light modulation device130, projection lens20, hermetic housing110, projector housing10, heat exchanger170, air guide wall115, and sirocco fans150and151. Projection lens20is configured to project light from light modulation device130. Hermetic housing110hermetically houses light modulation device130. Projector housing10contains hermetic housing110. Heat exchanger170(an example of the heat absorption part) is located at the upper section of hermetic housing110and is configured to absorb heat received from hermetic housing110and to radiate the heat to the outside of hermetic housing110. Air guide wall115is located in hermetic housing110and partitions the air guide passage S2, which extends along the bottom surface of hermetic housing110, from the main space S1containing light modulation device130. Air guide wall115includes communication part115band openings115a. Communication part115badjoins heat exchanger170and provides communication between the air guide passage S2and the main space S1. Openings115afunction as an inlet for guiding air from the main space S1into the air guide passage S2after the air has passed through heat exchanger170. Sirocco fans150and151(first sirocco fans) are located at the inlet and are configured to introduce the air in the main space S1into the air guide passage S2, to guide the air in the air guide passage S2to communication part115b, and to blow the air from communication part115bto heat exchanger170.

Thus, light modulation device130, which is to be protected from dust, is sealed with hermetic housing110and is thus rendered dust-proof. Furthermore, the components in hermetic housing110are properly arranged to improve radiation performance, thereby allowing projector1to be minimized. To be more specific, the air guide passage S2is defined by air guide wall115and extends along the bottom surface of hermetic housing110. This arrangement creates rectified airflow at the bottom of housing110, enabling more efficient release of heat from the bottom surface of housing110to the outside of housing110. Furthermore, the air in the main space S1can be heated to a high temperature because of containing light modulation device130as the heating element. This air is introduced by sirocco fans150and151into the air guide passage S2, fed through the air guide passage S2to heat exchanger170, absorbed by heat exchanger170, and radiated to the outside of housing110. In this manner, the air inside hermetic housing110is effectively cooled to improve radiation performance.

According to an aspect of the present disclosure, in projector1, when seen along the optical axis L of projection lens20, sirocco fans150and151are located opposite to heat exchanger170with respect to light modulation device130.

This configuration allows hermetic housing110to have a longer distance of airflow between sirocco fans150,151and heat exchanger170. As a result, air can be circulated throughout hermetic housing110, thereby further improving the radiation performance of projector1.

According to another aspect of the present disclosure, in projector1, sirocco fans150and151are located at the first lateral part of hermetic housing110, heat exchanger170is located at the second lateral part, which is on the opposite side of hermetic housing110from the first lateral part, and projection lens20is located so that the optical axis L is located between the first lateral part and the second lateral part. This configuration enables the air in hermetic housing110guided by sirocco fans150and151to be circulated around the optical axis L.

Heat exchanger170, which is located in heat exchanger case114at the lateral part of hermetic housing110, can radiate heat from the side surface of housing110to the outside of housing110. Furthermore, sirocco fans150and151are located at the lateral part of housing110opposite to heat exchanger case114. This configuration increases the distance of airflow between sirocco fans150,151and heat exchanger170as mentioned above so as to cool the entire hermetic housing110. In addition, projection lens20is located so that the optical axis L is located between the two lateral parts, and the air is circulated around the optical axis L in hermetic housing110. In projector1, many optical components may be located along the optical axis L of projection lens20. In this case, the cooling mechanism including heat exchanger170and sirocco fans150,151can be located at each lateral part outside the region where these optical components are located. This configuration can reduce the influence of the cooling mechanism on the optical components.

According to another aspect of the present disclosure, in projector1, projector housing10and hermetic housing110share the bottom surface.

When these housings10and110share the bottom surface, the radiation from the bottom surface of hermetic housing110(i.e., the bottom surface of projector housing10) results in the radiation from projector1to the outside. This improves the radiation performance of projector1.

According to another aspect of the present disclosure, projector1includes sirocco fans160and161(second sirocco fans), which are located in communication part115band oriented to heat exchanger170.

Sirocco fans160and161ensures the flow of air from communication part115bto heat exchanger170. This configuration further improves the radiation performance of projector1.

According to another aspect of the present disclosure, projector1further includes sirocco fans140-142(third sirocco fans), which are oriented to light modulation device130.

Sirocco fans140-142are provided to directly cool light modulation device130, which is the heating element, so as to further improve the radiation performance of projector1.

According to another aspect of the present disclosure, projector1further includes detection part31for detecting the attachment state of detachable projection lens20and a control device. The control device includes determination part32for determining whether or not the attachment state detected by detection part31indicates that projection lens20is in a detached state, and fan-stop part33for stopping sirocco fans150and151when determination part32has determined that projection lens20is in the detached state.

Assume that detection part31detects the attachment state of projection lens20, and determination part32of control device30has determined that the attachment state indicates that projection lens20is in the detached state. In this case, fan-stop part33of control device30stops sirocco fans140-142,150-151, and160-161. This configuration prevents sirocco fans140-142,150-151, and160-161from drawing dust into hermetic housing110when projection lens20is detached. Although it is preferable to stop all of sirocco fans140-142,150-151, and160-161as in the present embodiment, it is alternatively possible to stop only some of them.

Other Embodiments

The first embodiment has been thus described as an example technique of the present disclosure. However, the technique of the present disclosure is not limited to this embodiment and can be applied to other embodiments obtained by modification, replacement, addition, omission, etc. Furthermore, the components described in the first embodiment may be combined to form additional embodiments. Examples of such additional embodiments will now be described.

According to another embodiment shown inFIG. 12, if the radiation performance of projector1of the first embodiment is not sufficient, additional cooling mechanism180is added to the structure of the first embodiment. Additional cooling mechanism180is used to cool DMDs131-133more efficiently. Mechanism180includes cooling pads181for cooling DMDs131-133, refrigerant pipe182for supplying a refrigerant to cooling pads181, refrigerant tanks183for keeping the refrigerant, and sirocco fans184for cooing heat exchanger170and the refrigerant. Cooling pads181are attached to DMDs131-133. Two refrigerant tanks183are cylindrical and placed one above the other at the lateral side of fan case113and heat exchanger case114. Two sirocco fans184are located outside fan case113; one is oriented to heat exchanger170and the other is oriented to the back. In other words, refrigerant tanks183and sirocco fans184are located outside hermetic housing110.

After being cooled by sirocco fans184, the refrigerant is supplied through refrigerant pipe182to cooling pads181, thereby cooling DMDs131-133. The refrigerant is then supplied through refrigerant pipe182to refrigerant tanks183and kept there, thereby being again cooled by sirocco fans184. The refrigerant can be thus circulated to cool DMDs131-133.

According to still another embodiment, if the radiation performance of projector1of the first embodiment is too high, either sirocco fans140-142or sirocco fans160and161can be omitted in the first embodiment. This can further miniaturize projector1.

According to still another embodiment, the technique of the present disclosure can also be applied to other than DLP projectors, such as liquid crystal display (LCD) projectors or liquid crystal on silicon (LCoS) projectors.

These embodiments have been described as example techniques of the present disclosure with the accompanying drawings and detailed explanation.

Note that some of the components shown in the accompanying drawings and described in detail are not essential to solve the above-mentioned problems but are given only to exemplify the technique of the present disclosure. Therefore, these components should not be regarded as essential just because they are shown in the accompanying drawings and described in detail.

Furthermore, these embodiments are example techniques of the present disclosure, and can be subject to modification, replacement, addition, omission, etc. within the scope of claims and their equivalents.

The present disclosure is applicable to projectors.