Electronic device and image projection apparatus

An electronic device includes a speaker; a speaker holder that holds the speaker; a main unit on which the speaker holder is mounted; a first mounting part formed on the speaker; a second mounting part formed on the speaker holder; a first elastic part that engages with both the first and second mounting parts; a third mounting part formed on the speaker holder; a fourth mounting part formed on the main unit; and a second elastic part that engages with both the third and fourth mounting parts. The speaker and the main unit are provided in such a manner as not to come into contact with each other under the condition that the first and second mounting parts engage with the first elastic part, and the third and fourth mounting parts engage with the second elastic part.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2012-198928 filed in Japan on Sep. 10, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device and an image projection apparatus.

2. Description of the Related Art

Image projection apparatuses have been known that generate an image for projection using light output from a light source based on image data transmitted from a personal computer or a video camera, and project the generated image for display onto a projection surface such as a screen. In such an image projection apparatus, it is desired that images can be projected large-sized, and that the distance between the image projection apparatus and the projection surface can be set as short as possible. Image projection apparatuses have been disclosed that adopt a short projection distance.

In such an image projection apparatus, a speaker is provided for outputting various types of operation sounds and an alarm sound for users. For example, in Japanese Laid-open Patent Publication No. 10-066179, an installation mechanism of the speaker is disclosed, in which a speaker unit is supported at its flange portion by a housing of an electronic device with a vibration absorbing member interposed therebetween. The vibration absorbing member includes a holder mounted on and inserted into an installation flange of the speaker unit, and a mounting part integrally formed on the holder and fixed to the housing of the electronic device. While the installation flange of the speaker unit is held by the holder, the mounting part is fixed to the housing of the electronic device by a screw.

Japanese Laid-open Patent Publication No. 08-116582 discloses a speaker fixing structure including a contact surface, a holding unit, and an elastic member. The contact surface makes the front part of the speaker come in contact with a supporting member made of synthetic resin. The holding unit engages with and holds a part of the speaker. The elastic member makes the speaker held by the holding unit bring into elastically contact with the contact surface.

With the structure in which the speaker is fixed with a screw to the housing of the electronic device with a vibration absorbing member interposed therebetween as described above, however, the vibration of the speaker transmitted to the housing of the electronic device cannot be completely prevented. The vibration absorbing member and the housing of the electronic device engage with each other with the screw, that is, they are rigidly connected together. A certain amount of vibration of the vibration transmitted from the speaker to the vibration absorbing member is thus transmitted to the housing of the electronic device although reduced to some extent. Especially when the housing of the electronic device serves as the housing of an image projection apparatus such as a projector, the vibration is finally transmitted to the projected images. This may cause a failure that when the volume of the speaker is increased, the projected images vibrate and generate poor visibility.

Therefore, there is a need for an electronic device and an image projection apparatus that are capable of suppressing vibration caused by a speaker.

SUMMARY OF THE INVENTION

According to an embodiment, there is provided an electronic device that includes a speaker; a speaker holder that holds the speaker; a main unit on which the speaker holder is mounted; a first mounting part formed on the speaker; a second mounting part formed on the speaker holder; a first elastic part that engages with both the first mounting part and the second mounting part; a third mounting part formed on the speaker holder; a fourth mounting part formed on the main unit; and a second elastic part that engages with both the third mounting part and the fourth mounting part. The speaker and the main unit are provided in such a manner as not to come into contact with each other under the condition that the first mounting part and the second mounting part engage with the first elastic part, and the third mounting part and the fourth mounting part engage with the second elastic part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment will be described in which an electronic device of the present invention is applied to a projector (an image projection apparatus) with reference to the accompanying drawings. The present invention can also be applied to other electronic devices that include a speaker and need suppression of vibration of the speaker, such as a personal computer and a television set.FIG. 1is a perspective view of a projector1andFIG. 2is a perspective view of the projector1in a state in which an upper cover2is removed.

As illustrated inFIGS. 1 and 2, a projector lens3is provided on the upper cover2. The projector lens3is capable of changing magnification of image data finally projected on a projection surface. In a main unit10included in the housing of the projector1, an optical device20, a light source device30, a speaker unit40, a housing unit50, and an air inlet60are provided.

FIG. 3is a cross-sectional view illustrating the detailed structure of the optical device20and the light source device30. As illustrated inFIG. 3, the optical device20includes an illumination mechanism20aand a projecting mechanism20b. The main unit of the optical device20includes a color wheel25, a light tunnel26, a relay lens27, a plane mirror28, and a concave mirror29. Each of these members is provided inside the body of the optical device20. The optical device20also includes an image forming unit21. The image forming unit21includes digital micromirror devices (DMDs) serving as an image forming device that forms images.

The color wheel25in a disk shape converts white light emitted from the light source device30into lights of red, green, and blue repeatedly in a certain unit of time and outputs the light to the light tunnel26. The light tunnel26has a tubular structure made of a plurality of glass plates bonded to each other, and outputs the light emitted from the color wheel25to the relay lens27. The relay lens27includes two lenses combined with each other, and concentrates the light output from the light tunnel26while correcting the axial chromatic aberration of the light. The plane mirror28and the concave mirror29reflect the light output from the relay lens27and guide the light to the image forming unit21, thereby concentrating the light. The image forming unit21includes digital micromirror devices (DMDs) having a rectangular surface formed with a plurality of micromirrors driven in a time-division manner based on data of a moving image or a still image. The DMDs process and reflect the projected light so that predetermined image data is formed.

The light source device30includes a high pressure mercury lamp as a light source. The light source device30irradiates the illumination mechanism20aof the optical device20with white light. In the illumination mechanism20a, the white light emitted from the light source device30is divided into red, green, and blue lights (RGB) and guided to the image forming unit21. The image forming unit21forms images according to a modulation signal and the projecting mechanism20bmagnifies the formed image and projects the magnified image.

An OFF light plate is provided in an upper portion in the vertical direction of the image forming unit21, that is, on the near side inFIG. 3. The OFF light plate receives unwanted light not used as a projected light L out of the light entering the image forming unit21. When light enters the image forming unit21, a plurality of micromirrors are activated by operations of the DMD in a time-division manner based on moving image data. The micromirrors reflect the light in use to the projector lens3and reflect the light to be discarded to the OFF light plate. In the image forming unit21, the light used for a projected image is reflected to the projecting mechanism20b, magnified through the projector lenses3, whereby the magnified image light is projected.

Next, the structure of the speaker unit40according to the embodiment will be described in detail. The speaker unit40is structured so that a speaker holder420holds a speaker410.FIGS. 4A and 4Bare perspective views of the speaker410viewed from different directions andFIGS. 5Aand5B are perspective views of the speaker holder420viewed from different directions.

As illustrated inFIGS. 4A and 4B, the speaker410includes a speaker vibration surface411, four bosses412each serving as a first mounting part, and a harness413. The speaker vibration surface411is a part from which sound from the speaker410is output. The respective bosses412extend nearly vertical from the four side surfaces of the speaker410. The harness413is a wire that supplies electrical power to the speaker410. The positions where the bosses412are formed will be described later.

As illustrated inFIGS. 5A and 5B, the following are formed in the speaker holder420: four first slits421each serving as a second mounting part, and four second slits422each serving as a third mounting part. The first slits421and the second slits422are U-shaped slits that fit to the shape of the elastic member described later. The first slits421are formed in the four side surfaces, i.e., the up and down, right and left side surfaces of the speaker holder420. The positions where the first slits421are formed correspond to the positions of the bosses412formed on the speaker410. The first slit421and the second slits422open in opposite directions from each other and are formed in a direction parallel to the direction the sound is output from the speaker410(i.e., perpendicular to the speaker vibration surface411). By forming the slits in such a manner, the speaker410can be supported more rigidly against the vibrations in both the front direction and the back direction. The second slits422are formed in the parts protruding from the right and left surfaces of the speaker holder420as illustrated inFIGS. 5A and 5B.

A harness slit423is formed in the speaker holder420. The harness slit423is used for guiding the harness413of the speaker410. One of the first slits421formed adjacent to the harness slit423and another one of the first slits421on the opposite side are formed at point-symmetric positions to each other with respect to a central point of the line that passes through the harness slit423in the speaker holder420.

FIG. 6is a perspective view illustrating the structure of an elastic part that engages with the mounting parts. As illustrated inFIG. 6, an elastic part430serving as a first elastic part and a second elastic part includes a groove431and a hole432. The groove431is formed along the circumferential direction on the outer circumferential surface of the cylindrical body of the elastic part430, and the hole432is formed along the central axis of the cylindrical body of the elastic part430. The groove431is formed preferably on the center in the height direction of the cylindrical body of the elastic part430. The elastic part430is made of a material with a high vibration absorption property such as a chloroprene rubber and a sponge.

FIGS. 7A to 7Care diagrams for explaining the order in which the speaker410, the speaker holder420, and the elastic parts430are assembled. As illustrated inFIG. 7A, the respective bosses412formed on the speaker410are inserted into the respective holes432of the elastic parts430. The boss412and the hole432have diameters of the size nearly equal to each other. This generates friction therebetween and thus prevents the elastic part430mounted on the speaker410from rotating about the boss412, whereby the boss412engages with the hole432.

As illustrated inFIG. 7B, the respective edges of the first slits421formed in the speaker holder420engage with their corresponding grooves431of the elastic parts430mounted on the speaker410. The size of the first slit421is slightly larger than the size of the groove431of the elastic part430. This helps fitting the respective first slits421into the grooves431. The width of the groove431is nearly equal to the thickness of the side surface of the speaker holder420, whereby the slits and the grooves engage with each other.FIG. 7Cillustrates a state in which the speaker410is mounted on the speaker holder420.

FIGS. 8A and 8Bare diagrams for explaining the order in which the elastic parts430are mounted on the speaker holder420. As illustrated inFIGS. 8A and 8B, the respective grooves431of the elastic parts430are fitted into the respective second slits422of the speaker holders420. The elastic part430here is the same member as the elastic part430mounted on the speaker410. This completes the speaker unit40including the speaker410and the speaker holder420.

FIGS. 9A and 9Bare perspective views illustrating a mode in which the speaker unit40is mounted on the main unit10. In the main unit10, two protruding portions51serving as a fourth mounting part are provided. The shape of the protruding portion51corresponds to that of the hole432of the elastic part430. When mounting the speaker unit40on the main unit10, the respective protruding portions51are firstly inserted into the respective holes432of the elastic parts430mounted on the second slits422, whereby the second slits422and the protruding portions51engage with each other with the elastic parts430interposed therebetween. In addition, two protruding portions53serving as a fourth mounting part are also provided in a detachable housing unit50. The housing unit50is mounted to the speaker unit40mounted on the main unit10so that the respective protruding portions53are inserted downward into the respective holes432of the elastic parts430mounted on the second slits422. This causes the second slits422and the protruding portions51to engage with each other with the elastic parts430interposed therebetween. In this state, the speaker410, the housing unit50, and the main unit10do not come into contact with each other, whereby the vibration generated by the speaker410are not transmitted directly to the projector1.

FIGS. 10A and 10Bare diagrams illustrating the positional relation between an air inlet60and the speaker unit40. As illustrated inFIGS. 10A and 10B, open air taken in by the air inlet60flows toward the speaker unit40. In other words, the speaker unit40is provided on the downwind side of the air inlet60.

With the mounting structure of the speaker according to the embodiment as described above, the speaker410and the speaker holder420, and the speaker holder420and the main unit10are respectively fixed to each other with the elastic parts430interposed therebetween. The vibration generated in the speaker410is, therefore, absorbed in the elastic part430between the speaker410and the speaker holder420, and the elastic parts430between the speaker holder420and the main unit10. This suppresses the vibration caused by the speaker410.

In addition, when mounting the elastic parts430to the speaker410or the speaker holder420, the mounting is always achieved by inserting a part of the member included in the speaker410or the speaker holder420into each other. This does not require a screw or other members, thereby further suppressing the vibration.

Furthermore, with the mounting structure of the speaker according to the embodiment, the second slits422are formed in the parts extending from the speaker holder420for the purpose of mounting the speaker holder420to the main unit10. This achieves the design of the position and the shape of the slits based on the shape of the main unit10, thereby increasing the flexibility of the design.

Furthermore, with the mounting structure of the speaker according to the embodiment, the first slit421and the second slit422of the speaker holder420are formed in a direction in parallel with the direction of the sound emitted from the speaker410. This effectively suppresses the vibration in the direction in which the loudest sound generated by the speaker410is emitted.

Furthermore, with the mounting structure of the speaker according to the embodiment, the speaker unit40is provided on the downwind side of the air inlet60. This parallels the sound stream and the air stream, thereby suppressing degradation of the sound quality of the speaker due to the intake of air.

In place of the above-described structure, another structure may be used as follows: a slit is provided on the speaker and a protruding portion is provided on the speaker holder that engage with each other with an elastic member interposed therebetween. In addition, the shape of the elastic part may be changed based on the shape of the mounting part and the material of the elastic part and may be substituted with another material as long as it is capable of absorbing the vibration.

The present invention can provide the advantageous effect of suppressing vibration caused by a speaker.