JP2006173943A - Thin-shaped display device with built in bass reflex speaker system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for preventing, relating to a small thin-shaped display device incorporating a bass reflex speaker system audio reproducing device, degradation in separation characteristics between left and right audio channels at reproducing of stereo program which is caused by the sound in middle/high frequency bands leaked and emitted from a bass reflex ports for left and right audio channels arranged closely. <P>SOLUTION: The sound radiation axis of the opening of a bass reflex port is set below and in front of a thin-shaped display device, so that the sound in middle/high frequency bands having strong directivity that reaches a listener and is positioned in front of the thin-shaped display device is subjected to larger attenuation than the sound in low frequency band. So degradation is prevented in separation characteristics of left and right audio channels at reproducing of stereo program. It is visually demonstrated to users that the thin-shaped display device is mounted with a bass reflex speaker system having high capability of reproducing bass. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a bass reflex speaker system for improving the low frequency range reproduction capability of an audio reproduction apparatus built in a thin display device. Specifically, the sound output axis of a bass reflex port is set to the front lower direction of the thin display device. Therefore, it is possible to prevent the left and right audio channel separation characteristics from being deteriorated during stereo program reproduction due to middle / high frequency sound leaking from the bass reflex port, and to arrange the bass reflex port opening in the viewer's visible region. Thus, it is possible to visually appeal to the user that the product is equipped with a bass reflex speaker system with excellent reproduction capability in a low frequency range.

As means for improving the low-frequency sound reproduction capability output from the audio reproduction apparatus, the diameter of the speaker diaphragm, the rigidity of the speaker diaphragm, the flexibility of the diaphragm support member of the speaker diaphragm, the speaker diaphragm support structure And a large-diameter speaker that keeps the lowest resonance frequency determined by factors such as the mass of the entire vibration system including the energizing voice coil for driving the speaker diaphragm in a large-volume speaker box. However, a bass-reflex speaker system using Helmholtz resonance has been devised, and sound reproduction in the low frequency range is good even when combined with a small-diameter speaker whose speaker's minimum resonance frequency is not sufficiently low, and a small-volume speaker box It became possible to realize the characteristics. Therefore, the bass reflex speaker system is widely used in small bookshelf type component audio products designed for a space-saving environment.

FIG. 4A is a front view showing a sound emitting part of a bass reflex speaker system according to the prior art of a thin display device incorporating a bass reflex speaker system, and FIG. 4B is a side view. In FIG. 4A, 12a indicates a left speaker unit, and 12b indicates a right speaker unit. In order to achieve good left and right audio channel separation characteristics during stereo program playback, it is necessary to increase the separation distance between the left speaker unit 12a and the right speaker unit 12b as much as possible. Usually, it is arrange | positioned at the both ends of a cabinet.

In FIG. 4A, 13a indicates a left bass reflex port, and 13b indicates a right bass reflex port. As described above, the left speaker unit 12a and the right speaker unit 12b are arranged at the left and right ends of the front surface of the cabinet 14, respectively. As a result, the arrangement positions of the left bass reflex port 13a and the right bass reflex port 13b are inevitably set. The left and right audio channel separation characteristics output from the left and right bass reflex ports are lowered near the front center. However, the auditory direction-of-arrival discrimination capability is not a practical problem because it is inferior to low-frequency sound mainly output from the bass reflex port as compared to sound in the middle / high frequency range.

FIG. 4C shows a block diagram of the audio output circuit. The left channel audio signal input from the left channel audio signal input terminal 12c drives the left speaker unit 12a via the left channel preamplifier 12e and the left channel power amplifier 12g. The left speaker portion 12a constitutes a Helmholtz resonance box for emphasizing the low frequency region indicated by a broken line in FIG. 4C, and is accommodated in a small speaker box having a left bass reflex port 13a. The speaker box is built in the cabinet 14. The right channel audio circuit is also provided separately with the same configuration as that of the left channel audio circuit, and a two-channel audio output function is realized.

The bass reflex loudspeaker system is a technical means that realizes an enhanced rich low-frequency sound output, and therefore, low-frequency sound is mainly output from the bass reflex port. However, middle / high frequency sound is leaked even at a low level. Even though the sound in the middle / high frequency range leaking from the bass reflex port is low level, the left and right bass reflex ports are close to each other, causing degradation of the left and right audio channel separation characteristics, and the stereophonic effect during stereo program playback. Damage. In FIG. 4 showing an embodiment of the prior art, the sound emitting axis directions of the left bass reflex port 13a and the right bass reflex port 13b are arranged on the front surface of the cabinet 14 of the thin display device so as to be directed toward the viewer. Therefore, the middle / high frequency audio output leaking from the left bass reflex port 13a and the right bass reflex port 13b deteriorates the left and right audio channel separation characteristics and impairs the stereophonic effect during stereo program playback. .

Therefore, in another embodiment of the prior art shown in FIGS. 5A to 5C, in order to improve the sound reproduction capability in the low frequency range, in addition to the left speaker portion 22a and the right speaker portion 22b, a low frequency A dedicated woofer 25 for selectively outputting the sound of the area is mounted, and a bass reflex speaker system is applied to the woofer 25. A bass reflex port 23 is disposed on the bottom surface of the cabinet 24, and the sound output axis direction from the bass reflex port 23 is directed from the bottom surface of the thin display device to the installation surface. However, since the mutual interval between the bass reflex port 23 and the installation surface on which the thin display device is installed becomes small, the radiation impedance of low frequency sound from the bass reflex port 23 due to the components of the installation surface or the surface condition of the installation surface Is affected and the sound effect fluctuates. Further, as shown in FIG. 5 (d), in order to extract a low frequency range audio signal, the left channel low pass filter 26a, the right channel low pass filter 26b, the superposition circuit 27, and further the low frequency range audio. A dedicated woofer power amplifier 28 is required, and the circuit configuration is complicated.
JP 2000-287287 “Speaker system and display device using the same”

In a thin display device equipped with a bass reflex speaker system that can reproduce low frequency sound that gives a rich sense of sound during audio program playback, the user can visually recognize the bass reflex port as the sound emission part of the low frequency sound By disposing on the front surface of the cabinet, it is possible to appeal to the user the excellent functionality of the audio playback device built in the thin display device. However, if the left and right bass reflex ports arranged in close proximity leak the middle / high frequency sound of the left and right audio channels of the stereo program, and the sound is emitted, the left and right audio channel separation characteristics deteriorate, resulting in stereo The stereophonic effect of the program is impaired.

In a thin display device incorporating a bass reflex speaker system as an audio playback device, the sound output axis direction from the bass reflex port is an angle of more than 0 degrees and less than 90 degrees, for example, the front lower direction with respect to the display screen of the thin display apparatus By disposing it inside, by utilizing the property that the directivity of the sound differs depending on the sound frequency, the middle / high frequency range sound leaking from the bass reflex port is selectively attenuated and positioned in front of the thin display device. Reaching the viewer's ear is prevented, and the stereophonic effect during stereo program playback is not impaired.

In addition, the bass reflex port opening is provided on the curved surface with the center of curvature diagonally below the front center of the cabinet of the thin display device, so that the user can visually recognize the bass reflex port as the sound emission part of the low frequency range sound. Further, it is possible to appeal to the user the superior functionality of the audio playback device built in the thin display device.

In addition, the speaker box is floatingly fixed to the front cabinet and / or the rear cabinet via a buffer member, so that the airtightness of the bass reflex port is maintained, and vibration from the speaker box propagates to the cabinet and is thinly displayed. It also suppresses problems such as the effect on the device screen.

Furthermore, by arranging the sound output shaft of the speaker and the sound output shaft of the bass reflex port at a predetermined angle in the state of the speaker box, processing on the cabinet side of the thin display device is simplified and the thin display device is provided. Assembling becomes easy.

The directivity of the sound emitted from the speaker differs depending on the frequency, and in the middle / high frequency range sound leaking from the bass reflex port of the bass reflex speaker system that mainly outputs the low frequency range sound, the low frequency range sound The directivity is stronger than that of voice, and it radiates strongly in the direction of the sound output axis, but abruptly attenuates in the angular direction away from the axis. Therefore, low-level medium / high-frequency sound that leaks from the bass reflex port that is arranged with the sound output axis directed downward in the front of the cabinet does not directly reach the ears of the viewer located in front of the cabinet. The left and right audio channel separation characteristics do not deteriorate, and it is possible to avoid fluctuations in the acoustic effect due to the influence of the installation surface on which the thin display device is installed.

In addition, the bass reflex port is provided on a curved surface having a center of curvature obliquely downward at the lower center of the front cabinet, so that the user can visually recognize the bass reflex port as a sound emission part of low frequency range sound, and the thin display It is also possible to appeal to the user the superior functionality of the audio playback device built into the device.

Furthermore, by arranging the sound output shaft of the speaker and the sound output shaft of the bass reflex port at a predetermined angle in the state of the speaker box, processing on the cabinet side of the thin display device is simplified and the thin display device is provided. Assembling becomes easy.

A case where the embodiment of the present invention is applied to a liquid crystal television will be described below with reference to the drawings. 1A is an external perspective view of the front surface of the liquid crystal television, FIG. 1B is a front view of the liquid crystal television main body, and FIG. 1C is a bottom view of the liquid crystal television main body. In FIG. 1, 1 is a liquid crystal television, 1a is a liquid crystal display panel for displaying images, 2a is a left speaker unit, 2b is a right speaker unit, 3a is a left bass reflex port of a bass reflex speaker system, 3b is a right bass reflex port, and 4 is a cabinet. Reference numeral 5 denotes a stand.

3 is a diagram showing a speaker box arranged on the right side of the liquid crystal television 1, FIG. 3 (a) is an external perspective view of the speaker box, and FIG. 3 (b) is a chain line HH in FIG. 1 (b). It is a longitudinal cross-sectional perspective view of the lower part of the liquid crystal television 1 cut | disconnected along the cutting line shown by. 3, 4a is a front cabinet, 4b is a rear cabinet, 4c is a bass reflex port opening, 6 is a speaker box, 6a is a speaker, 6b is a port for bass reflex, 6c is a duct, 6d is a floating rubber, and 6e is a rubber spacer. Indicates. The speaker box 6 is configured as a Helmholtz resonance box by integrating the speaker 6a and the port 6b. In addition, although the figure of the speaker box arrange | positioned at the left side is abbreviate | omitted, the position of the speaker 6a and the port 6b of the speaker box 6 arrange | positioned at the right side is reversely arranged, and is similarly comprised as a Helmholtz resonance box.

Further, the liquid crystal display panel 1a for displaying an image, the speaker 6a, and the left speaker are attached in substantially parallel planes, and the left bass reflex port 3a and the right bass reflex port 3b are curved obliquely downward at the lower center of the front cabinet 4a. A curved surface having a center is provided at an angle of about 40 degrees with the surface of the liquid crystal display panel 1a. In the speaker box 6, the sound output axis of the speaker 6a and the sound output axis of the port 6b are also provided at an angle of approximately 40 degrees.

The speaker box 6 has a rubber spacer 6e fitted into the port 6b portion, and then the floating rubber 6d and the rubber spacer 6e for the three speaker box 6 mounting bosses and the bass reflex port opening 4c provided in the front cabinet 4a, respectively. After fixing the position, it is fixed with screws. In the final assembly process of the liquid crystal television 1, the rear cabinet 4b is fixed to the front cabinet 4a side, but the speaker box 6 is fixed only to the front cabinet 4a.

The rubber spacer 6e keeps the confidentiality between the port 6b and the right bass reflex port 3b, and also suppresses propagation of vibration from the speaker box 6 to the cabinet 4 by being fixed to the front cabinet 4a together with the floating rubber 6d. ing. The speaker box located in the left speaker unit 2a is also assembled in the same manner as the right speaker unit 2b, and is provided separately for the left and right audio channels.

The left bass reflex port 3a and the right bass reflex port 3b mainly output low-frequency sound, but medium / high-frequency sound of approximately 3000 Hz or higher is leaked although it is at a lower level than low-frequency sound. Is output. However, the mid / high frequency range sound has higher directivity than the low frequency range sound and radiates strongly in the direction of the sound output axis, but abruptly attenuates in the angular direction away from the sound output axis. Therefore, low-level medium / high-frequency sound that leaks from the bass reflex ports 3 a and 3 b arranged with the sound output axis directed downward in the front of the cabinet 4 is not received by the viewer's ears located in front of the cabinet 4. It does not reach directly and does not cause deterioration of the left and right audio channel separation characteristics during stereo program playback.

FIG. 2A is a longitudinal sectional view of the main body of the liquid crystal television 1 cut along a cutting line indicated by a chain line CC in FIG. The sound output shaft from the left bass reflex port 3a disposed on the bottom surface of the cabinet 4 is directed downward in the front of the cabinet 4 as shown by a chain arrow "A" in FIG. ) The direction from the left bass reflex port 3a indicated by the chain line arrow “B” toward the viewer 7 positioned in front of the liquid crystal television 1 is offset by the angle “α” shown in FIG. ing.

FIG. 2B schematically shows the directivity characteristics of the voice in the low frequency range mainly output from the left bass reflex port 3a as a vector diagram by broken lines. As shown in FIG. 2B, the sound pressure level “E” in the low frequency range reaching the ear of the viewer 7 is substantially equal to the sound pressure level in the sound output axis direction “D” of the bass reflex port 3a. Become. However, as shown in the directional characteristic diagram of the sound in the middle / high frequency range in FIG. 2 (c), the sound pressure level “G” in the middle / high frequency range reaching the ear of the viewer 7 is equal to the bass reflex port 3a. It is significantly attenuated from the sound pressure level in the sound emission axis direction “F”.

As described above, the sound pressure level in the middle / high frequency range reaching the viewer 7 can be selectively lowered by directing the sound output axis direction of the left bass reflex port 3a to the lower front of the cabinet 4. Thus, it is possible to prevent the left and right audio channel separation characteristics from deteriorating and to avoid the loss of the stereophonic effect during stereo program playback. In the above description, the left bass reflex port 3a is taken as an example, but it should be noted that the same applies to the right bass reflex port 3b.

The bass reflex ports 3a and 3b are provided on a curved surface having a center of curvature obliquely downward at the lower center of the front cabinet 4a so as to form an angle of about 40 degrees with the surface of the liquid crystal display panel 1a. The bass reflex ports 3a and 3b as the sound emitting portions can be visually recognized by the user, and the excellent functionality of the audio playback device built in the thin display device can be appealed to the user.

In the present embodiment, the bass reflex ports 3a and 3b are provided on the curved surface having the center of curvature obliquely downward at the lower center of the front cabinet 4a and at an angle of about 40 degrees with the surface of the liquid crystal display panel 1a. However, the same effect can be obtained by providing the front and rear sides of the cabinet 4 in the upper, lower, left and right peripheral portions.

The present invention describes a thin display device incorporating a bass reflex speaker system as an example. However, it is difficult to install the bass reflex port on the back surface of the speaker box by placing the back surface of the speaker box in contact with the wall surface. It is also suitable for adapting to a wall-mounted bass reflex speaker system.

(A) of the liquid crystal television which is an Example of this invention is an external appearance perspective view, (b) is a front view of a liquid crystal television main body, (c) is a bottom view of a liquid crystal television main body. (A) is a longitudinal sectional view cut along a cutting line CC indicated by a chain line in FIG. 1 (b), (b) is a directivity characteristic in a low frequency range sound, and (c) is a mid / high frequency range sound. It is a schematic diagram which shows the directional characteristic in. (A) of the speaker box which is an Example of this invention is an external appearance perspective view, (b) is a longitudinal cross-sectional perspective view of the lower part of the liquid crystal television cut | disconnected along the cutting line HH in FIG.1 (b). (A) which shows the Example of a prior art is a front view, (b) is a side view, (c) is an audio | voice circuit block diagram. (A) is a front view, (b) is a side view, (c) is a bottom view, and (d) is an audio circuit block diagram showing another embodiment of the prior art.

Explanation of symbols

1: liquid crystal television 1a: liquid crystal display panel 2: speaker unit 2a: left speaker unit 2b: right speaker unit 3: bass reflex port 3a: left bass reflex port 3b: right bass reflex port 4: cabinet 4a: front cabinet 4b: rear cabinet 4c: Bass reflex port opening 5: Stand 6: Speaker box 6a: Speaker 6b: Port 6c: Duct 6d: Floating rubber 6e: Rubber spacer
7: Viewer 12: Speaker unit 12a: Left speaker unit 12b: Right speaker unit 12c: Left channel audio signal input terminal 12d: Right channel audio signal input terminal 12e: Left channel preamplifier 12f: Right channel preamplifier 12g: Left channel power amplifier 12h: Right channel power amplifier 13: Bass reflex port 13a: Left bass reflex port 13b: Right bass reflex port 14: Cabinet 22: Speaker unit 22a: Left speaker unit 22b: Right speaker unit 22c: Left channel audio signal input terminal 22d : Right channel audio signal input terminal 22e: left channel preamplifier 22f: right channel preamplifier 22g: left channel power amplifier 22h: right channel power amplifier 23: bass reflex port 24: cabinet 25: woofer 26 Low-pass filter 26a: left channel low-pass filters 26b: right channel low pass filter 27: superimposing circuit 28: woofer power amplifier

Claims (7)

In the thin display device with built-in bass reflex speaker system, the sound output axis of the bass reflex port is arranged at an angle θ with respect to the display screen of the thin display device with built-in bass reflex speaker system, and the angle is 0 degree <θ <90 degrees. A thin display device with a built-in bass reflex speaker system. In the thin display device with built-in bass reflex speaker system, the display screen of the thin display device with built-in bass reflex speaker system and the sound emitting surface of the speaker are arranged substantially in parallel, and the sound emitting axis of the bass reflex port is at an angle with respect to the display screen and the sound emitting surface of the speaker. A thin display device with a built-in bass reflex speaker system, wherein θ is disposed and the angle is 0 ° <θ <90 °. A thin display device with a built-in bass reflex speaker system, characterized in that a sound output axis of a bass reflex port is set in a forward and downward direction with respect to the display screen of the thin display device with a built-in bass reflex speaker system. A thin display device with a built-in bass reflex speaker system, characterized in that a bass reflex port is provided on a curved surface having a center of curvature obliquely downward at the center of the front lower part of the cabinet of the thin display device with a built-in bass reflex speaker system. . In the bass-reflex speaker system built-in thin display device according to claim 1, a speaker box in which a speaker and a bass-reflex port are integrated is fixed to a front cabinet and / or a rear cabinet of the bass-reflex speaker system built-in thin display device, A thin display device with a built-in bass reflex speaker system, which is disposed between the front cabinet and the rear cabinet. 6. A thin display device with a built-in bass reflex speaker system according to claim 5, wherein the speaker box is floatingly fixed to the front cabinet and / or the rear cabinet via a buffer member. apparatus. 7. A thin display device with a built-in bass reflex speaker system according to claim 5, wherein the sound emitting axis of the speaker of the speaker box and the sound emitting axis of the bass reflex port are arranged with an angle θ, and the angle Is a thin display device with built-in bass reflex speaker system, wherein 0 ° <θ <90 °.

Images