JP7827278B2 - Earphone body, earpiece and earphone - Google Patents

Description

This invention relates to an earphone body, earpiece, and earphone combination that can improve sound quality with a simple structure.

In recent years, with the widespread use of mobile phones and smartphones, there have been more and more opportunities to listen to music and other hobby sources.

In particular, efforts have been made to improve acoustic characteristics in earphones in order to achieve higher sound quality. However, improving acoustic characteristics is only one element in achieving higher sound quality. Until now, in-head localization has been the norm with earphones and headphones, and the reality is that there has been little progress in sound image localization, resolution, or three-dimensional natural sound. Compatible types are limited to a small number of high-priced products that use DSPs (digital audio processors), with the exception of products such as the earpiece JIJU (registered trademark, relisted 2019/146590) sold by the applicant. To date, there have been very few compatible products with simple structures and low costs.

When sound quality is a particular priority for earphones, many people choose in-ear type earphones, which are inserted directly into the ear canal. Like headphones, in-ear type earphones deliver sound directly to the ear canal, which means they largely ignore the structure of the ear, resulting in problems such as in-head localization, where sound is heard near the top of the head, poor localization, where sound is concentrated in the center of the head, and poor resolution. Even today, these problems remain unresolved in most models, with a few exceptions.

prior art

In commercially available earphones, sound generally travels from the nozzle to the earpiece through a cylindrical sound passageway before reaching the ear canal. As a result, the direct sound from the earphone is the main sound, resulting in in-head localization and low resolution localization. To solve this problem, Patent Document 1 proposes an approach to achieving out-of-head localization by directing a portion of the sound from the earphone body forward and then taking that sound into a hole in the stem in the same direction.

Patent Document 2 also describes an approach that enables extra-head localization (forward localization) by directing sound emitted from the tip of an earpiece built into an earphone directly to the anterior tragus wall of the ear canal or by reflecting it and having it reach the eardrum.

Balanced armature (BA) earphones often use multiple sound sources with different characteristics to cover the entire range of the sound source, so to prevent multiple sounds from overlapping on their way to the nozzle outlet, they are designed to transmit sound to the nozzle outlet using a pipe (tube) that is divided into sound paths corresponding to the multiple sound sources. For this reason, a tube with the cross section shown in Figure 1(C) is sometimes used, and this tube has multiple sound paths formed along its entire length.

Patent No. 5666797 Patent No. 4913256 Japanese Patent Application Laid-Open No. 2017-028525

The objective of this invention is to solve these problems by utilizing the linearity of sound produced by a linear sound source, a feature of line array speakers, in earphones, thereby improving the direction and linearity of sound emitted.

The earphone main body of the present invention is configured by forming a sound adjustment path in the sound path of the nozzle portion, which is the sound output portion of the earphone main body, divided into multiple parts above and below by approximately horizontal partitions.
The sound adjusting path is configured by dividing the sound path into multiple parts, one above the other, by one or two approximately horizontal partitions across the entire width of the sound path , and each part has the same length, is shorter than the length of the sound path, and does not reach the open end of the sound path. The single reproduced sound is divided into upper and lower parts by the partitions, so that sounds of the entire range of the reproduced sound are propagated by each sound adjusting path (claim 1).
The ratio of the length of the partition to the inner diameter of the nozzle is effective when it is in the range of 0.8 to 2 (claim 2), and the effect gradually decreases when it is less than 0.8, and the sound becomes sluggish and the sense of speed decreases when it exceeds 2. Numerically, a ratio of about 1.2 to 1.6 is considered to be the most preferable ratio based on experience.
If the divider is made of a partition plate, the earphone body of the present invention can be obtained by using an existing earphone body (claim 3).

The earpiece of this invention is configured by forming a sound path in the earpiece that is connected to the nozzle portion, which is the sound output portion of the earphone body, with a sound adjustment path that is divided into upper and lower halves. The sound adjustment paths are of the same length, and the single reproduced sound is divided into upper and lower halves by the partition (Claim 4).
In the earpiece, the ratio of the length of the partition to the inner diameter of the nozzle is preferably in the range of 0.8 to 2 (claim 5), and the partition is preferably made of a partition plate (claim 6).
However, the diameter of the open side hole of the nozzle of most earpieces is 5 to 6 mm, and if a ratio of 0.8 to 2 is applied to earpieces with an axial length of approximately 8 to 10 mm, the earphone assembly area will be reduced to 3 to 4 mm, which may cause problems such as the earphone becoming easily disconnected or interference between the tip of the earphone nozzle and the partition plate.As such, depending on the earpiece, it may be necessary to allow a ratio of up to approximately 0.5 to the nozzle inner diameter.

The earphone main body of claim 1 can achieve the effect of improving sound quality even when used in combination with an earpiece that does not have a sound adjusting path. Also, the earpiece of claim 4 can achieve the effect of improving sound quality even when used in combination with an earphone main body that does not have a sound adjusting path.
The earphone of claim 7 is a combination of an earphone main body with a sound adjusting path and an earpiece with a sound adjusting path. In this case, it is possible to find an effect when there are space constraints for the earphone main body and the earpiece.
Furthermore, in this invention, the earphone body can be configured to have two or more identical sound sources (driver units), with each sound source propagating along a separate sound adjustment path.

First, the tuning path, which is the main feature of the present invention, will be explained.
Normally, sound emitted from a speaker is emitted radially from a point source. In the case of ordinary earphones, the sound emitted from the speaker's driver unit is emitted while diffusing towards the opening of the nozzle through a sound path with a circular cross section, transmitted to the eardrum through the ear canal, and recognized as sound. If sound, which is intended to be diffused, is forced to travel through a cylindrical sound path, it is easy to imagine that the sound will be diffused and reflected inside the cylinder, resulting in a worse sound than the original.

Most ordinary speakers are point sound sources, but in recent years, a different type of speaker, the line array type, has been used in concert halls and other venues due to the need to deliver sound to a large number of people.
The line array method is known to have the ability to deliver linear sound that also travels horizontally over long distances by suppressing vertical sound diffusion, rather than using a point sound source, by arranging multiple speakers with essentially the same characteristics vertically to form a linear sound source.
In order to effectively utilize the characteristics of this line array in earphones, the present invention divides the sound path from the driver unit into two or more sections, one above the other, and provides a sound adjustment path. Note that in this invention, "upper and lower" refers to the "upper and lower" positions when the earphones are worn in the ears.

The reason for dividing the sound path into upper and lower sections is as follows.
The problem with most earphones and headphones is that they ignore the structure of the ear, making it difficult for sound to spread horizontally.
To overcome this issue, it is effective to take advantage of the characteristics of line array speakers, which have the ability to diffuse sound horizontally. In this case, by dividing the sound channel into upper and lower sections to form a sound-tuning path, it is possible to give the speaker the ability to diffuse sound horizontally. However, simple experiments have confirmed that if the sound-tuning path is made diagonal or vertical, the sound can sound unnatural or even be perceived as narrow.

The sound adjusting path formed in the earphone main body and the sound adjusting path formed in the earpiece are formed in multiple numbers, one above the other, and specific examples of these paths include the following.
In Fig. 1, (A) to (C) show two sound adjusting paths a, one above the other, formed in the sound path of the earphone main body or earpiece, (A) has a partition plate b arranged in the center of the sound path, with the upper and lower sound adjusting paths being the ones above and below, (B) and (C) have a partition c provided by molding the sound path tube, forming two sound adjusting paths a above and below. (D) and (E) show three sound adjusting paths a, one above and one below, formed in the sound path, (D) has the sound path divided by a partition plate b, and (E) is formed by molding.

The (A) configuration is considered preferable because it can obtain a large effective opening area (approximately 95%). Although the partition partially reduces the opening area, it has been confirmed that for a typical nozzle with an inner diameter of 3-4 mm, if an effective opening area of 50% or more is ensured, the reduction in opening area has almost no effect on sound quality. The (C) configuration is often used in BA-type earphones to guide high and low frequencies through a pipe (tube). However, in relation to this invention, the sounds divided into upper and lower frequencies are not identical, and there are differences in the frequency range, making it difficult to achieve an effective line array effect. Furthermore, there are limitations, such as the effective opening diameter being less than 50%, and a tendency for deterioration in sound quality is observed in comparative evaluation results.
It has also been confirmed that even if the partition plate does not come into contact with the inner wall of the sound path, the effect can be seen as long as it covers more than about 70% of the inner diameter of the sound path.
If the thickness of the partitions at A, B, D, and E in Figure 1 is too thin, it can cause resonance, so the appropriate range is thought to be about 5% to 20% of the opening diameter. For example, if the opening diameter is 4 mm, a thickness of 0.2 mm to 0.8 mm is thought to be appropriate.
Previous experiments have confirmed that the same effect can be achieved regardless of the position of the sound adjustment path, regardless of the part of the sound path that runs from the nozzle of the earphone body to the tip opening of the earpiece.

The length of the tuning path is effective when the ratio of the inner diameter of the sound path is in the range of 0.8 to 2, and the effect gradually decreases when it is less than 0.8, and when it exceeds 2, the sound becomes sluggish and the sense of speed decreases. Numerically, a ratio of around 1.2 to 1.6 is considered to be good as a rule of thumb. The length can be determined according to the sound quality desired.
It is preferable that the angle at which the partition of the sound adjusting path is positioned be within about ±5 degrees of the horizontal direction when in use. If the angle of the partition is off by about 5 degrees even on one ear side, the sense of positioning begins to feel unnatural, and it has been confirmed that if the partition is rotated 90 degrees and the sound adjusting paths are positioned on the left and right, the sound deteriorates to the state without the sound adjusting path.

The material of the partition can be metal, resin, rubber, wood, paper, etc., but by flexibly selecting each material, the role of the partition can be ensured. The material is selected taking into consideration sound quality.
Furthermore, the present invention can also be implemented by attaching a partition plate to an existing earphone body or earpiece.

In the earphone body of this invention, sound from the earphone body is divided into multiple parts, up and down, by sound adjustment paths that are divided into upper and lower parts in the sound path, which is the inner cavity of the nozzle, and the sound, which remains divided into multiple parts up and down, is emitted toward the ear canal space via the sound path of the earpiece.
In the earpiece of this invention, the sound from the earphone body is also divided into multiple parts, up and down, by the sound adjustment path that is divided into upper and lower parts in the sound path, and the sound that remains divided into multiple parts up and down is released into the ear canal space.

To expand on this, by installing a sound conditioning path in the nozzle or earpiece of the earphone body, it is possible to change the point sound source emitted from the driver unit into a line sound source divided in the vertical direction. This prevents diffuse reflections from occurring when the sound passes through the sound path of the nozzle and earpiece from a point sound source. Furthermore, by creating a linear sound source, a line array effect can be obtained, so the sound travels horizontally and is transmitted to the eardrum in a straight line, suppressing unnecessary diffuse reflections of sound.
In other words, in this invention, by passing the sound through the sound adjusting path, the user can obtain high-quality sound with unprecedented sound image localization, resolution, and reduced in-head localization, as the sound is diffused laterally while unnecessary diffused sound in the ear canal space is suppressed.

FIG. 2 is a cross-sectional view showing an example of a sound adjusting path according to the present invention. 1 is a perspective view of an embodiment of an earphone main body of the present invention. FIG. 2 is a cross-sectional view of an embodiment of the earphone body of the present invention. 1 is a perspective view of an embodiment of an earpiece of the present invention. 1 is a cross-sectional view of an embodiment of an earpiece of the present invention. 1 is a cross-sectional view showing an embodiment of an earphone according to the present invention; FIG. 10 shows the results of comparative study 1. A diagram of the earphones used in comparative study 2. FIG. 10 shows the results of comparative study 2. 1 is a diagram showing the results of a survey conducted in Example 1 of the present invention. FIG. 10 is a diagram showing the results of a survey conducted in Example 2 of the present invention.

An embodiment of this invention is described below.

This embodiment relates to an earphone main body A and is shown in FIGS.
Earphone main body A is equipped with a driver unit 1, and a nozzle 2 is provided in the direction of emitted sound, with an earpiece B attached to the tip of the nozzle 2. Sound emitted from the driver unit 1 passes through the nozzle 2, passes through the earpiece B attached to the entrance of the ear canal, and reaches the ear canal and the eardrum.

A partition plate 4 is attached substantially horizontally to the sound path 3 (inner diameter 4 mm) which is the bore of the nozzle 2, dividing the sound path into upper and lower halves, and the sound path 3 of the nozzle 2 is divided into upper and lower halves by the partition plate 4, with sound adjustment paths 5 provided on the top and bottom. It is desirable that the cross-sectional areas of the upper and lower sound adjustment paths 5 be equal.
The length of the partition plate 4 is 6 mm (1.5 times the inner diameter of the sound path 3), and the thickness of the partition plate is 0.4 mm (10% of the inner diameter of the sound path 3). The length of the partition plate is shorter than the length of the sound path.

If there is a filter at the tip of the nozzle 2, a partition plate can be attached to the area excluding the filter, or a partition plate can be installed between the nozzle 2 and the earpiece B without attaching a filter.

This embodiment relates to earpiece B and is shown in FIGS.
Earpiece B comprises a cup portion 6, and a partition plate 8 that divides the sound path 7, which is the cavity inside the cup portion 6, into upper and lower halves is attached substantially horizontally. The sound path 7 is divided into upper and lower halves by the partition plate 8, and sound adjusting paths 9 are provided on the top and bottom. The inner diameter of the sound path 7 is 5 mm, the length of the partition plate 8 is 5 mm (1.0 times the inner diameter of the sound path 7), and the thickness of the partition plate 8 is 0.5 mm (10% of the inner diameter of the sound path 7). The length of the partition plate is shorter than the length of the sound path.

This embodiment is an earphone C that combines the earphone main body A shown in Example 1 with the earpiece B shown in Example 2.

Examples 1 to 3 all have in common the fact that a partition plate is placed in the sound path and sound adjustment paths are provided above and below the partition plate, and they also share the same effects, so they will be explained together below.

The sound path 3 of the earphone main body A and the sound path 7 of the earpiece B are divided into two parts, upper and lower, by partition plates 4 and 8 to form a sound adjustment path, so the point sound source generated by the driver unit 1 can be changed into a line sound source that is divided into two or more parts in the vertical direction. By providing a sound adjustment path, the sound is divided and turned into a line sound source, giving it a line array effect, and the sound reaches the eardrum with diffuse sound reflection within the outer ear suppressed. This reproduces natural sound with little influence from diffuse sound reflection.
This effect can be obtained whether the sound adjusting path is provided only in the earphone body A or in the earpiece B, but by providing the sound adjusting path in both, the effect can be further enhanced and the degree of freedom in setting the sound adjusting path can be increased.

The results of the sensory test are shown below.
[Survey implementation guidelines]
1. Survey dates: February 13, 2024 - June 15, 2024
2. Number of participants: 9 (8 men, 1 woman)
3. Age composition: Men and women in their 30s to 60s 4. Survey method: One jazz song was selected and the earphones and earpiece combinations were changed and evaluated.
Comparison (5-point system) with an example of the present invention, where the combination of an earphone main body and an earpiece (Comparative Example 1) does not have a sound adjustment path and has a cylindrical sound path with a circular cross section, was given an evaluation of 3 points for each item.
[Survey items]
1. Quality of the bass range 2. Quality of the midrange 3. Quality of the treble range 4. Realism 5. Positioning 6. Connection between left and right sounds 7. Sound clarity 8. Out-of-head positioning (forward positioning)
9. Speed

[Comparative Example 1]
A combination of an earphone body and earpiece that does not have a sound adjustment path and has a cylindrical sound path with a circular cross section.
[Result summary]
-Sound quality issues remain with in-head positioning.
Overall, the sound quality is rated low.
In this survey, all items were scored on a scale of 3 points (see Figure 7).

[Comparative Example 2]
A combination of an existing earphone main body (see Figure 8) that does not have a sound adjustment path and has a nozzle with two holes along the entire length of the sound path, and an earpiece that does not have a sound adjustment path and has a cylindrical sound path with a circular cross section.
[Result summary]
Compared to the results of Comparative Study 1, there was a slight improvement in the sense of localization and out-of-head localization, but it could not be considered a significant improvement (Figure 9). The sounds divided into upper and lower sections are not the same, and there is a difference in the frequency range, making it difficult to find an effective line array effect, and if the effective opening diameter of the nozzle is small, no noticeable effect can be obtained even if the holes are lined up vertically.

[Example 1]
A combination of the earphone body of Example 1 with a sound adjustment path and an earpiece without a sound adjustment path.
[Result summary]
Improvements in sound quality were observed in all nine items compared to comparison studies 1 and 2.
See Figure 10 for details.

[Example 2]
A combination of an earphone main body without a sound adjustment path and the earpiece of Example 2 with a sound adjustment path.
[Result summary]
Improvements in sound quality were observed in all nine items compared to comparison studies 1 and 2.
Details are as shown in Figure 11.

This invention can improve sound quality with a simple structure that involves forming a sound adjustment path in the sound path, and has industrial applicability.

A: Earphone body B: Earpiece C: Earphone 1: Driver unit 2: Nozzle 3: Sound path 4: Partition plate 5: Sound adjustment path 6: Cup portion 7: Sound path 8: Partition plate 9: Sound adjustment path

Claims (7)

An earphone main body having one or more driver units that output one reproduced sound into one sound path, and in part of the sound path of the nozzle part, which is the sound output part of the earphone main body, there is a sound adjustment path that is divided into multiple parts above and below by one or two approximately horizontal partitions that span the entire width of the sound path, and which is of the same length, is shorter than the length of the sound path, and does not reach the open end of the sound path , and the one reproduced sound is divided into upper and lower parts by the partitions, so that sounds of the entire range of the reproduced sound are propagated by each sound adjustment path . The earphone body of claim 1, wherein the length of the partition is in the range of 0.8 to 1.6 in terms of the ratio to the inner diameter of the sound path . An earphone main body as described in claim 1 or 2, wherein the sound adjustment path is configured by disposing partition plates in the upper and lower central portions of the sound path. An earpiece that is connected to a nozzle, which is the sound output section of an earphone main body equipped with one or more driver units that output a single reproduced sound, characterized in that part of the sound path of the earpiece has a sound adjustment path of the same length that is divided into multiple sections by only one or two approximately horizontal partitions that span the entire width of the sound path, and the single reproduced sound is divided into upper and lower sections by the partitions. 5. The earpiece according to claim 4, wherein the ratio of the length of the partition to the inner diameter of the sound passage of the earpiece is in the range of 0.8 to 1.6 . 6. The earpiece according to claim 4 , wherein the sound adjustment path is configured by disposing partition plates in the upper and lower central portions of the sound path. An earphone comprising the earphone body of claim 1 or 2 and the earpiece of claim 4 or 5 attached thereto.