U.S. patent application number 14/459920 was filed with the patent office on 2015-06-25 for electronic apparatus, electronic device, and light-transmissive cover member.
The applicant listed for this patent is KYOCERA Corporation. Invention is credited to Shin Murakami, Motohiro Umehara.
Application Number | 20150177431 14/459920 |
Document ID | / |
Family ID | 53267866 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150177431 |
Kind Code |
A1 |
Umehara; Motohiro ; et
al. |
June 25, 2015 |
ELECTRONIC APPARATUS, ELECTRONIC DEVICE, AND LIGHT-TRANSMISSIVE
COVER MEMBER
Abstract
An electronic apparatus, a light-transmissive cover member, and
an electronic device are disclosed. The electronic apparatus may
include an image display device that includes an image display
surface and a light-transmissive cover member. The
light-transmissive cover member is arranged such that at least part
of the light-transmissive cover member faces the image display
surface. The light-transmissive cover member is a single crystal
that contains alumina (Al.sub.2O.sub.3) as a main component. Due to
the light-transmissive cover member, the transmittance of light
having a wavelength of 260 nm is less than 92% of the transmittance
of light having a wavelength of approximately 550 nm.
Inventors: |
Umehara; Motohiro;
(Yasu-shi, JP) ; Murakami; Shin; (Omihachiman,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KYOCERA Corporation |
Kyoto-shi |
|
JP |
|
|
Family ID: |
53267866 |
Appl. No.: |
14/459920 |
Filed: |
August 14, 2014 |
Current U.S.
Class: |
381/333 ;
359/361 |
Current CPC
Class: |
H04M 1/0279 20130101;
H04M 1/0266 20130101; H04R 2400/03 20130101; H04R 2499/11 20130101;
G02B 1/02 20130101; G02B 5/208 20130101; H04R 17/005 20130101; H04M
1/03 20130101 |
International
Class: |
G02B 5/20 20060101
G02B005/20; H04R 17/00 20060101 H04R017/00; G02B 1/02 20060101
G02B001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2013 |
JP |
2013-264697 |
Claims
1. An electronic apparatus, comprising: an image display device
comprising an image display surface; and a cover member, comprising
a single crystal sapphire body mainly containing alumina (Al203),
arranged to at least partially face the image display surface, the
cover member being light-transmissive and having a first
transmittance of light having a wavelength of 260 nm that is less
than 92% of a second transmittance of light having a wavelength of
550 nm.
2. The electronic apparatus according to claim 1, wherein the first
transmittance is less than 72% of the second transmittance.
3. The electronic apparatus according to claim 1, wherein the first
transmittance is less than 50% of the second transmittance.
4. The electronic apparatus according to claim 1, wherein the cover
member has a first average value of transmittances of lights having
wavelengths between 230 nm and 300 nm is less than 92% of a second
average value of transmittances of lights having wavelengths
between 500 nm and 800 nm.
5. The electronic apparatus according to claim 4, wherein the first
average value is less than 85% of the second average value.
6. The electronic apparatus according to claim 1, wherein the cover
member further comprises at least one element selected from a group
consisting of Co, Ni, Na, Ti, Cr, Fe, and Cu in a total amount of
3.times.10.sup.-4% by mass or more.
7. The electronic apparatus according to claim 1, wherein the cover
member further comprises at least one element selected from a group
consisting of Ti, Fe, and Cu in a total amount of
3.times.10.sup.-4% by mass or more.
8. The electronic apparatus according to claim 1, wherein the cover
member contains Cr.
9. The electronic apparatus according to claim 8, wherein the
amount of Cr is 5.times.10.sup.-5% by mass or more, and a thickness
of the cover member in a direction perpendicular to a principal
surface is smaller than 1 mm.
10. The electronic apparatus according to claim 1, wherein the
cover member contains alumina whose content ratio of oxygen is
smaller than the ideal chemical equivalent.
11. The electronic apparatus according to claim 1, wherein the
image display surface is planar, and the cover member is a plate
that includes a planar surface facing the image display
surface.
12. The electronic apparatus according to claim 1, wherein the
cover member is a plate having a rectangular shape in a plan
view.
13. The electronic apparatus according to claim 1, wherein the
image display device is a liquid crystal display panel or an
organic EL device.
14. The electronic apparatus according to claim 1, further
comprising: a piezoelectric vibrating element arranged on the cover
member that vibrates by a driving voltage based on a sound
signal.
15. The electronic apparatus according to claim 14, wherein the
piezoelectric vibrating element vibrates for transmitting a
conduction sound based on the sound signal.
16. The electronic apparatus according to claim 14, wherein the
piezoelectric vibrating element has a long and narrow rectangular
plate shape.
17. The electronic apparatus according to claim 14, further
comprising: wherein the piezoelectric vibrating element is arranged
in a position which is not overlapped with the image display
device.
18. A light-transmissive cover member for an electronic apparatus
that is disposed such that at least part of the light-transmissive
cover member faces an image display surface of an image display
device, the light-transmissive cover member comprising a single
crystal sapphire body containing alumina as a main component, and
having a transmittance of light having a wavelength of 260 nm which
is less than 92% of a transmittance of light having a wavelength of
550 nm.
19. The light-transmissive cover member according to claim 18,
further having an average value of a transmittance (%) of light
having a wavelength range of 230 nm to 300 nm which is less than
92% of an average value of a transmittance (%) of light having a
wavelength range of 500 nm to 800 nm.
20. An electronic device, comprising: an image display device
comprising an image display surface; and a light-transmissive
sapphire cover member, at least partially covering the image
display surface, and having first and second transmittances of
light having a wavelength of 260 nm and 550 nm respectively,
wherein the first transmittance is less than 85% of the second
transmittance.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority under 35 USC
.sctn.119 to Japanese Patent Application No. 2013-264697 filed on
Dec. 21, 2013, entitled "Electronic Apparatus and
Light-Transmissive Cover Member", the entirety of which is
incorporated herein by reference.
FIELD
[0002] The present invention relates to an electronic apparatus and
a light-transmissive cover member.
BACKGROUND
[0003] Electronic apparatuses currently in use often have a
plurality of functional units. These functional units may include a
wireless communication unit and an image display device. In
particular, portable electronic devices known as smartphones and
tablets, which may include relatively larges displays as well as a
touch panel for an input device, have become more widespread.
However, in recent years, there is growing concern about the
adverse effects these apparatuses may have on the eyes of their
operators due to the light emitted from an image display surface of
an image display device.
SUMMARY
[0004] An electronic device and light-transmissive cover member are
presented. The electronic apparatus may include an image display
device that includes an image display surface and a
light-transmissive cover member. The light-transmissive cover
member is arranged such that at least part of the
light-transmissive cover member faces the image display surface.
The light-transmissive cover member is a single crystal that
contains alumina (Al.sub.2O.sub.3) as a main component. Due to the
light-transmissive cover member, the transmittance of light having
a wavelength of 260 nm is less than 92% of the transmittance of
light having a wavelength of approximately 550 nm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1A is a perspective view illustrating the external
appearance of an exemplary electronic apparatus.
[0006] FIG. 1B is a perspective view schematically illustrating a
light-transmissive cover member included in the electronic
apparatus illustrated in FIG. 1A.
[0007] FIG. 2 is a front view illustrating the exemplary external
appearance of the electronic apparatus.
[0008] FIG. 3 is a rear view illustrating the external appearance
of the exemplary electronic apparatus.
[0009] FIG. 4 is a cross-sectional view illustrating the exemplary
electronic apparatus.
[0010] FIG. 5 is a graph of luminosity function.
[0011] FIG. 6 is a graph illustrating an example of spectral
transmittance of one version of the light-transmissive cover
member.
[0012] FIG. 7 is a graph illustrating an example of spectral
transmittance of another version of the light-transmissive cover
member.
[0013] FIG. 8 is a block diagram illustrating an electrical
configuration of the exemplary electronic apparatus.
[0014] FIG. 9 is a plan view illustrating a piezoelectric vibrating
element.
[0015] FIG. 10 is a side view illustrating the piezoelectric
vibrating element.
[0016] FIG. 11 is a view illustrating the piezoelectric vibrating
element in a state of being curved.
[0017] FIG. 12 is a view illustrating the piezoelectric vibrating
element in a state of being curved.
[0018] FIG. 13 is a plan view illustrating a light-transmissive
cover member.
[0019] FIG. 14 is a view describing an air conduction sound and a
conduction sound.
DESCRIPTION
[0020] The following description is presented to enable a person of
ordinary skill in the art to make and use the embodiments of the
disclosure. The following detailed description is exemplary in
nature and is not intended to limit the disclosure or the
application and uses of the embodiments of the disclosure.
Descriptions of specific devices, techniques, and applications are
provided only as examples. Modifications to the examples described
herein will be readily apparent to those of ordinary skill in the
art, and the general principles defined herein may be applied to
other examples and applications without departing from the spirit
and scope of the disclosure. The present disclosure should be
accorded scope consistent with the claims, and not limited to the
examples described and shown herein.
[0021] Embodiments of the disclosure are described herein in the
context of one practical non-limiting application, namely, an
electronic apparatus such as a mobile phone. Embodiments of the
disclosure, however, are not limited to such mobile phone, and the
techniques described herein may be utilized in other applications.
For example, embodiments may be applicable to e-readers, digital
cameras, electronic game machines, digital music players, personal
digital assistants (PDA), tablets, personal handy phone system
(PHS), laptop computers, TV's, Global Positioning Systems (GPS's)
or navigation systems, health equipment, and other communication
devices. As would be apparent to one of ordinary skill in the art
after reading this description, these are merely examples and the
embodiments of the disclosure are not limited to operating in
accordance with these examples. Other embodiments may be utilized
and structural changes may be made without departing from the scope
of the exemplary embodiments of the present disclosure.
[0022] <External Appearance of Electronic Apparatus>
[0023] FIG. 1A is a perspective view schematically describing an
electronic apparatus 100 as an embodiment of an electronic
apparatus, and FIG. 1B is a perspective view schematically
illustrating a light-transmissive cover member 1 included in the
electronic apparatus illustrated in FIG. 1A.
[0024] FIG. 2 is a front view illustrating the electronic apparatus
100.
[0025] FIG. 3 is a rear view illustrating the electronic apparatus
100. For example, the electronic apparatus 100 according to the
embodiment is a mobile phone.
[0026] FIG. 4 is a cross-sectional view schematically illustrating
the electronic apparatus 100.
[0027] As illustrated in FIGS. 1A to 4, the electronic apparatus
100 includes the light-transmissive cover member 1, a casing 2, and
an image display device 52 that includes an image display surface
52a. The light-transmissive cover member 1 is a plate having a
rectangular shape in a plan view or top view. An apparatus case 3
is configured by combining the light-transmissive cover member 1
and the casing 2.
[0028] The light-transmissive cover member 1 is disposed such that
at least part of the light-transmissive cover member 1 faces the
image display surface 52a. When the image display surface 52a of
the electronic apparatus 100 is planar, the light-transmissive
cover member 1 may be a plate-like member including a planar first
surface 1A which faces the image display surface 52a. Further, the
light-transmissive cover member 1 may be a plate-like member
including a second surface 1B parallel to the first surface 1A.
[0029] The light-transmissive cover member 1 is a single crystal
with alumina (Al.sub.2O.sub.3) as a main component. In the
embodiment, the meaning of "main component" or "mainly" is that the
component is contained by the amount of at least 50% by mass and
preferably 70% by mass. The single crystal with alumina
(Al.sub.2O.sub.3) as a main component is generally known as
sapphire. It is difficult to damage or break sapphire. Furthermore,
sapphire has high thermal conductivity and high heat dissipation
when compared to strengthened glass and other similar
materials.
[0030] The conventional single crystal of alumina (Al.sub.2O.sub.3)
has high purity and few lattice defects, such as oxygen defects.
The conventional single crystal of alumina (Al.sub.2O.sub.3) is
colorless and transparent. The transmittance of light through the
conventional single crystal of alumina (Al.sub.2O.sub.3) varies
with wavelength. For example, the transmittance of light having a
wavelength of approximately 260 nm is approximately 94% of the
transmittance of light having a wavelength of approximately 550
nm.
[0031] In contrast, in the light-transmissive cover member 1 of the
embodiment, the transmittance of light having a wavelength of
approximately 260 nm is less than 92% of the transmittance of light
having a wavelength of approximately 550 nm. That is, the
light-transmissive cover member 1 has a relatively suppressed
transmittance of light having a wavelength corresponding to that of
ultraviolet light. In terms of suppressing the transmittance of
light having a wavelength corresponding to that of ultraviolet
light, in the light-transmissive cover member 1, it is preferable
that the transmittance of light having a wavelength of 260 nm is
less than 72% of the transmittance of light having a wavelength of
approximately 550 nm. It is more preferable that the transmittance
of light having a wavelength of 260 nm is less than 50% of the
transmittance of light having a wavelength of approximately 550
nm.
[0032] In addition, in the conventional single crystal of alumina
(Al.sub.2O.sub.3), the average value of the transmittance of light
having a wavelength range of approximately 230 nm to 300 nm is
approximately 92% to 100% of the average value of the transmittance
of light having a wavelength range of approximately 500 nm to 800
nm. In contrast, in the light-transmissive cover member 1, the
average value of a transmittance of light having a wavelength range
of approximately 230 nm to 300 nm is less than 92% of an average
value of a transmittance of light having a wavelength range of
approximately 500 nm to 800 nm. That is, in the light-transmissive
cover member 1, the transmittance of light having a wavelength
range corresponding to that of ultraviolet light is suppressed when
compared to the transmittance of light through the conventional
single crystal of alumina (Al.sub.2O.sub.3). When white light is
transmitted through the light-transmissive cover member 1, the
color of the light transmitted through the light-transmissive cover
member 1 may be more purplish red than the color of light which is
incident to the light-transmissive cover member 1.
[0033] In terms of suppressing the transmittance of light having a
wavelength corresponding to that of ultraviolet light more, in the
light-transmissive cover member 1, the average value of the
transmittance of light having a wavelength range of approximately
230 nm to 300 nm is preferably less than 85% of an average value of
a transmittance of light having a wavelength range of approximately
500 nm to 800 nm. The average value of the transmittance of light
having a wavelength range of 230 nm to 300 nm is an arithmetic mean
value of the transmittance of each wavelength measured at 2 nm
intervals in the wavelength range of 230 nm to 300 nm. The
transmittance of light can be measured using a spectrophotometer
such as the UV-3100PC manufactured by Shimadzu Corporation.
[0034] The light-transmissive cover member 1 includes a display
portion 1a on which various pieces of information such as
characters, symbols, and figures are displayed. The display portion
1a may have a rectangular shape in a plan view or top view. A
peripheral edge region 1b which surrounds the display portion la in
the light-transmissive cover member 1 may be black or dark due to a
film or the like being attached thereto. The peripheral edge 1b is
a non-display portion on which the information is not displayed. A
touch panel 53 is attached to an inner surface of the
light-transmissive cover member 1. A user can issue various
instructions with respect to the electronic apparatus 100 by
operating the display portion 1b of the light-transmissive cover
member 1 with a finger or the like.
[0035] The casing 2 constitutes the peripheral edge region of the
front surface, the side surface, and the rear surface of the
electronic apparatus 100. The casing 2 may be made of a
polycarbonate resin or of any other material so long as the
material is a member which covers the electronic apparatus. For
example, a material which is the same as that of the
light-transmissive cover member 1 may be used for the casing 2.
[0036] The image display device 52 is included in the inside of the
electronic apparatus 100 as described above. The image display
device 52 is controlled by the control unit 50 described below and
displays image information indicating characters, symbols, and
figures on the image display surface 52a.
[0037] The image display device 52 is a so-called liquid crystal
display panel. It has a backlight unit and a liquid crystal layer.
The backlight unit may include an LED lamp. The LED lamp may emit
white light, and it may include a luminescent material and a blue
LED element. The white light emitted from the LED lamp is partially
colored by being transmitted through the liquid crystal layer
included in the image display device 52 so that the image
information displayed on the image display surface 52a of the image
display device 52 is formed. While the white light emitted from the
LED lamp is transmitted through the liquid crystal layer, the color
of the transmitted light is changed by limiting the wavelength
range of the light being transmitted for each part of the liquid
crystal layer. Thus the image information indicating characters,
symbols, and figures having various colors and shapes is formed on
the image display surface 52a. The light indicating the image
information formed on the image display surface 52a in this manner
is incident to the first surface 1A of the light-transmissive cover
member 1, emits from the second surface 1B, and enters eyes of a
user of the electronic apparatus 100. The user recognizes the
characters, symbols, and figures indicated by the image
information.
[0038] FIG. 5 is a graph illustrating a luminosity function in
which intensity of brightness felt by eyes of a human for each
wavelength of light is represented by a numerical value. More
specifically, the graph illustrated in FIG. 5 represents a CIE
(International Commission on Illumination) luminosity function. As
illustrated in the graph of the luminosity function of FIG. 5, most
people perceive that light having a wavelength of 550 nm as the
brightest and all other colors are not as bright. The light having
a wavelength of approximately 550 nm is substantially green light.
Light having a wavelength of 260 nm is ultraviolet light and is not
perceptible to humans. A wavelength range of approximately 500 nm
to 800 nm is corresponding to the color range from green to red. A
wavelength range of approximately 230 nm to 300 nm is corresponding
to ultraviolet light.
[0039] Since light having a wavelength range of approximately 230
nm to 300 nm is not visible, people tend to continuously watch
image display device 52 unconsciously having high light intensity
for a long time unaware of the exposure to UV light, and thus the
light damages the eyes of a human unknowingly because the energy is
relatively high.
[0040] In the light-transmissive cover member 1, the transmittance
of light having a wavelength range with a low luminosity function
and high energy is set to be less thanthe transmittance of light
having a wavelength range with a high luminosity function and low
energy.
[0041] In the electronic apparatus 100 including the
light-transmissive cover member 1, the above-described image
display device 52 is a so-called liquid crystal display panel. The
white light from the backlight may contain a relatively large
amount of light having a wavelength range of approximately 230 nm
to 300 nm, which is light that has relatively high energy. The
light-transmissive cover member 1 may more easily absorb light
having a wavelength range with relatively high energy.
[0042] Various images such as operation screens, game images,
photos, or moving images are displayed on the image display device
52, and the user who operates the electronic apparatus 100 tends to
watch the image display device 52 for a long time. For example,
since light having a wavelength 300 nm or lower with relatively
high energy is not visible, the operator may continuously watch the
image display device 52 unconsciously for a long time unaware of
the exposure to UV light. The light-transmissive cover member 1
suppresses the amount of light, which is easily incident to eyes of
the operator in a large amount, having a wavelength range
corresponding to that of ultraviolet light so that adverse effects
on eyes of the operator can be suppressed.
[0043] <First Aspect of Light-Transmissive Cover Member>
[0044] A light-transmissive cover member of a first aspect contains
cobalt (Co), nickel (Ni), sodium (Na), titanium (Ti), chromium
(Cr), iron (Fe), and copper (Cu) in a total amount of
3.times.10.sup.-4% by mass or more. Further, one or more elements
among Co, Ni, Na, Ti, Cr, Fe, and Cu may not be contained in the
light-transmissive cover member. In addition, it is preferable that
the light-transmissive cover member contain Ti, Fe, and Cu in a
total amount of 3.times.10.sup.-4% by mass or more. Similarly, one
or more elements among Ti, Fe, and Cu may not be contained in the
light-transmissive cover member. Each of Co, Ni, Ti, Cr, Fe, and Cu
are transition metals, and Na is an alkali metal. Sapphire is
colored when a small amount of any thereof is contained in the
sapphire. The color and the concentration thereof, that is, an
absorption spectrum of transmitted light by sapphire is changed due
to a combination of the transition metals or alkali metals
contained in sapphire, and the balance among content ratios of the
respective transition metals and alkali metals. In the case where
Co, Ni, Na, Ti, Cr, Fe, and Cu are contained in a total amount of
3.times.10.sup.-4% by mass or more, for example, absorption of
light having a wavelength of 300 nm or less becomes higher. Among
the metal elements, the degree of coloration of sapphire is higher
when Ti, Fe, or Cu is present. In order to increase absorption of
light having a wavelength of 300 nm or less, it is preferable that
Ti, Fe, and Cu be contained in a total amount of 3.times.10.sup.-4%
by mass or more.
[0045] The content ratios of the metal elements in the
light-transmissive cover member 1 can be measured using a glow
discharge mass spectrometer. For example, as a measuring device, a
double-convergence type GDMS device(VG9000, VG Elemental Inc.) is
used for measuring a sample in which sapphire is powered under the
conditions of a discharge power of 1.0 kV and 2.5 mA, a resolution
of 4000, and an auxiliary electrode of Ga (6N:30 mm.phi. to 1
mmt).
[0046] When the light-transmissive cover member 1 of the first
aspect is used, ultraviolet light incident to eyes of the operator
can be effectively suppressed while the light transmitting member 1
is transparent to the degree that the operator does not consider
the image information displayed on the image display surface 52a to
be exceedingly red. As an example, the light-transmissive cover
member of the first aspect may contain the following amounts:
[0047] approximately 0.5.times.10.sup.-6% by mass to
1.5.times.10.sup.-6% by mass of Co, [0048] approximately
0.5.times.10.sup.-5% by mass to 1.5.times.10.sup.-5% by mass of Ni,
[0049] approximately 0.5.times.10.sup.-5% by mass to
1.5.times.10.sup.-5% by mass of Na, [0050] approximately
0.5.times.10.sup.-4% by mass to 1.5.times.10.sup.-4% by mass of Ti,
[0051] approximately 1.5.times.10.sup.-5% by mass to
2.5.times.10.sup.-5% by mass of Cr, [0052] approximately
1.5.times.10.sup.-4% by mass to 2.5.times.10.sup.-4% by mass of Fe,
[0053] and approximately 0.5.times.10.sup.-4% by mass to
1.5.times.10.sup.-4% by mass of Cu.
[0054] The graph of FIG. 6 illustrates the spectrum transmittance
of a metal element-containing single crystal containing Co, Ni, Na,
Ti, Cr, Fe, and Cu in a total amount of 3.times.10.sup.-4% by mass
or more and an example of a conventional (or normal) single crystal
containing Co, Ni, Na, Ti, Cr, Fe, and Cu in a total amount of less
than 3.times.10.sup.-4% by mass under the same conditions. More
specifically, the metal element-containing single crystal of the
graph illustrated in FIG. 6 contains Ti, Fe, and Cu in a total
amount of 3.times.10.sup.-4% by mass or more. For example, the
metal element-containing single crystal contains, for example,
approximately 1.times.10.sup.-6% by mass of Co, approximately
1.times.10.sup.-5% by mass of Ni, approximately 1.times.10.sup.-5%
by mass of Na, approximately 1.times.10.sup.-4% by mass of Ti,
approximately 2.times.10.sup.-5% by mass of Cr, approximately
2.times.10.sup.-4% by mass of Fe, and approximately
8.times.10.sup.-5% by mass of Cu.
[0055] FIG. 6 is a graph of respective examples obtained by
measuring single crystals respectively having a thickness of 4.3
mm. The spectrum transmittance illustrated in FIG. 6 is data
obtained by measuring the transmittance of light respectively
having a wavelength of 2 nm using a spectrophotometer such as the
UV-3100PC manufactured by Shimadzu Corporation.
[0056] As is evident from the graph in FIG. 6, while a conventional
single crystal has a wide wavelength range and substantially
uniform transmittance, the light-transmissive cover member 1
comprised of the metal element-containing single crystal has a low
transmittance in the wavelength range of ultraviolet light. That
is, while the light from the image display device 52 is transmitted
through the light-transmissive cover member 1 of the first aspect,
the light-transmissive cover member 1 absorbs a relatively large
amount of light in the range containing ultraviolet light having a
relatively high energy.
[0057] In the example of FIG. 6, in the normal single crystal, the
transmittance of light having a wavelength of approximately 260 nm
is approximately 94% of the transmittance of light having a
wavelength of approximately 550 nm. In contrast, in the metal
element-containing single crystal body, the transmittance of light
having a wavelength of approximately 260 nm is approximately 69% of
the transmittance of light having a wavelength of approximately
550, which is a smaller value.
[0058] In addition, in the example of FIG. 6, in the normal single
crystal, the average value of a transmittance of light having a
wavelength range of approximately 230 nm to 300 nm is 79% while the
average value of a transmittance of light having a wavelength range
of approximately 500 nm to 800 nm is 86%. Thus the average value of
a transmittance of light having a wavelength range of approximately
230 nm to 300 nm is approximately 93% of the average value of a
transmittance of light having a wavelength range of approximately
500 nm to 800 nm, which is a comparatively large value. In
contrast, in the metal element-containing single crystal, the
average value of a transmittance of light having a wavelength range
of approximately 230 nm to 300 nm is 70% while the average value of
a transmittance of light having a wavelength range of approximately
500 nm to 800 nm is approximately 86%. Thus the average value of a
transmittance of light having a wavelength range of approximately
230 nm to 300 nm is approximately 81% of an average value of a
transmittance of light having a wavelength range of approximately
500 nm to 800 nm, which is a comparatively small value. In the case
of using the light-transmissive cover member 1 of the first aspect,
which contains transition elements in a greater amount than
conventional sapphire, ultraviolet light incident to eyes of the
operator can be effectively suppressed while the image information
displayed on the image display surface 52a is transparent to the
degree that the operator does not consider the image information to
be exceedingly red.
[0059] <Second Aspect of Light-Transmissive Cover Member>
[0060] A light-transmissive cover member 1 of a second aspect
contains Cr. Cr is one of the transition metals, but Cr can
strongly color sapphire red even when Cr is contained in sapphire
even in small amounts. More specifically, the light-transmissive
cover member 1 of the second aspect is a single crystal body
containing alumina (Al.sub.2O.sub.3) as a main component and
contains, for example, 1.times.10.sup.-5% by mass or more of Cr.
The transmitted light of a crystal body allowing the single crystal
containing alumina (Al.sub.2O.sub.3) to contain a small amount of
Cr is purplish red. When the light-transmissive cover member 1
contains Cr, 1.times.10.sup.-5% by mass or more of Cr is necessary
to be contained in the light-transmissive cover member 1. The
content ratio of Cr in the light-transmissive cover member 1 can be
measured using, for example, the above-described double-convergence
type GDMS device (VG9000, VG Elemental Inc.) under conditions the
same as the conditions described in paragraph 42.
[0061] Similarly, in the case of using the light-transmissive cover
member 1 of the second aspect, ultraviolet light incident to eyes
of the operator can be effectively suppressed while the light
transmitting member 1 is transparent to the degree that the
operator does not consider the image information displayed on the
image display surface 52a to be exceedingly red.
[0062] FIG. 7 is a graph illustrating the wavelength dispersion of
the spectral transmittance when white light is radiated on the
Cr-containing single crystal and then transmitted there through.
FIG. 7 also illustrates a graph indicating wavelength dispersion
values of the spectrum transmittance under the same conditions as
in the single crystal of alumina (Al.sub.2O.sub.3) containing no Cr
(hereinafter referred to as the normal or conventional single
crystal). The thickness of the normal single crystal illustrated in
FIG. 7 is the same as that of the light-transmissive cover member
1, which is 4.3 mm. The spectrum transmittance illustrated in FIG.
7 is data obtained by measuring transmittance using a UV-3100PC
(manufactured by Shimadzu Corporation). The Cr-containing single
crystal of the graph in FIG. 7 is a single crystal containing
approximately 4.times.10.sup.-4% by mass of Cr.
[0063] In the example of FIG. 7, for example, in the Cr-containing
single crystal body of the embodiment, the transmittance of light
having a wavelength of approximately 260 nm is approximately 90% of
the transmittance of light having a wavelength of approximately
550, which is a small value. In addition, the average value of a
transmittance of light having a wavelength range of approximately
230 nm to 300 nm is approximately 77% while the average value of a
transmittance of light having a wavelength range of approximately
500 nm to 800 nm is approximately 86%. Thus, the average value of a
transmittance of light having a wavelength range of approximately
230 nm to 300 nm is approximately 90% of an average value of a
transmittance of light having a wavelength range of approximately
500 nm to 800 nm, which is a comparatively small value.
[0064] As is evident from the graph in FIG. 7, while a conventional
single crystal has a wide wavelength range and substantially
uniform transmittance, the light-transmissive cover member 1
comprised of the Cr-containing single crystal has a low
transmittance in the wavelength range shorter than approximately
550 nm. The wavelength range shorter than approximately 550 nm
includes both a wavelength range of ultraviolet light and a
wavelength range of high energy visible (HEV) light.
[0065] In the transparent crystal body containing a single crystal
of alumina (Al.sub.2O.sub.3) as a main component, redness of light
to be transmitted increases as the content ratio of Cr increases.
Additionally the redness also increases as the thickness increases.
In terms of being transparent to the degree that the operator does
not consider the image information to be exceedingly red, it is
preferable that the light-transmissive cover member 1 formed of a
transparent crystal body contains a single crystal of alumina
(Al.sub.2O.sub.3) as a main component contain 5.times.10.sup.-4% by
mass or more of Cr and the thickness in a direction perpendicular
to the first surface is less than 1 mm.
[0066] <Third Aspect of Light-Transmissive Cover Member>
[0067] A light-transmissive cover member 1 of a third aspect
contains alumina (Al.sub.2O.sub.3) whose content ratio of oxygen is
smaller than that of the ideal chemical equivalent as a main
component. The ideal chemical formula of the single crystal of
alumina is Al.sub.2O.sub.3. The chemical formula of the single
crystal of the third aspect is represented by Al.sub.2O.sub.3-x,
and the content ratio of oxygen is smaller than that of the ideal
chemical equivalent. The oxygen-deficient single crystal can be
grown by adjusting conditions of the atmosphere and the like at the
time of growth of the single crystal. The oxygen-deficient single
crystal whose content ratio of oxygen is smaller than the ideal
chemical equivalent has an energy level which may largely absorb
the light having a wavelength range of approximately 230 nm to 300
nm.
[0068] Specifically, in an oxygen-deficient single crystal body,
the transmittance of light having a wavelength of approximately 260
nm is less than approximately 85% of the transmittance of light
having a wavelength of approximately 550 nm. In addition, the
average value of the transmittance of light having a wavelength
range of approximately 230 nm to 300 nm is less than 90% of the
average value of the transmittance of light having a wavelength
range of approximately 500 nm to 800 nm. In the case of using the
light-transmissive cover member 1 comprised of the oxygen-deficient
single crystal, light having relatively high energy incident to
eyes of the operator can be effectively suppressed while the light
transmitting member 1 remains transparent to the degree that the
operator does not consider the image information displayed on the
image display surface 52a to be exceedingly red.
[0069] The image display device 52 was previously described as
being a so-called liquid crystal display panel including the LED
lamp as the backlight unit. However, the image display device is
not limited to that particular configuration. For example, a liquid
crystal display device including a so-called fluorescent lamp as a
backlight unit and other kinds of image display devices such as a
so-called organic electroluminescent (EL) device and the like may
be used. Since the light emitted from other image display devices
contains so-called high energy visible light having a wavelength of
approximately 380 nm to 400 nm which is close to violet in color,
the light-transmissive cover member 1 suppresses the amount of
light having a wavelength range corresponding to that of high
energy visible light incident to the eyes of the operator so that
adverse effects on eyes of the operator are suppressed in this
case.
[0070] As illustrated in FIG. 3, a speaker hole 20 and a microphone
hole 21 are formed on a rear surface 101 of the electronic
apparatus 100, that is, the rear surface of the apparatus case 3.
Further, an imaging lens 58a including an imaging unit 58 described
below is exposed from the rear surface 101 of the electronic
apparatus 100.
[0071] Electrical Configuration of Electronic Apparatus
[0072] FIG. 8 is a block diagram illustrating an electrical
configuration of an electronic apparatus 100. As illustrated in
FIG. 8, the electronic apparatus 100 includes the control unit 50,
a wireless communication unit 51, the image display device 52, the
touch panel 53, a piezoelectric vibrating element 55, an external
speaker 56, a microphone 57, an imaging unit 58, and a battery 59,
and these constituent elements are arranged in the apparatus case
3.
[0073] The control unit 50 includes a CPU 50a and a storage unit
50b and manages overall operations of the electronic apparatus 100
by controlling other configuration elements of the electronic
apparatus 100. The storage unit 50b is configured of a ROM and a
RAM. Various functional blocks are formed in the control unit 50 by
the CPU 50a executing various programs in the storage unit 50b.
[0074] The wireless communication unit 51 receives a signal from a
communication device such as a web server connected to the Internet
or a mobile phone and separate from the electronic apparatus 100
using an antenna 51a via a base station. The wireless communication
unit 51 performs an amplification process and down conversion on
the received signal and outputs the signal to the control unit 50.
The control unit 50 performs demodulation processing or the like on
the input received signal and acquires a sound signal indicating a
voice or music included in the received signal. Further, the
wireless communication unit 51 performs up-converting and the
amplification process on a transmission signal including a sound
signal or the like generated in the control unit 50, and transmits
the transmission signal after the process from the antenna 51a in a
wireless manner. The transmission signal from the antenna 51a is
received in a communication device connected to the Internet or a
mobile phone and separate from the electronic apparatus 100 via the
base station.
[0075] The image display device 52 may be a liquid crystal image
display device as described above and displays various pieces of
information such as characters, signals, and figures on the image
display surface 52a by being controlled by the control unit 50. The
information displayed on the image display device 52 can be
recognized by the user of the electronic apparatus 100 by being
displayed on the display portion la of the light-transmissive cover
member 1.
[0076] The touch panel 53 may be a projection type electrostatic
capacitance touch panel and detects an operation of the user with
respect to the display portion la of the light-transmissive cover
member 1. The touch panel 53 is attached to the inner surface of
the light-transmissive cover member 1 and includes two sheet-like
electrode sensors which are disposed so as to face each other. Two
electrode sensors are bonded to each other using a transparent
adhesive sheet.
[0077] A plurality of long and narrow X electrodes which
respectively extend along an X-axis direction (for example, a
lateral direction of the electronic apparatus 100) and are disposed
in parallel with each other are formed in one electrode sensor. A
plurality of long and narrow Y electrodes which respectively extend
along a Y-axis direction (for example, a vertical direction of the
electronic apparatus 100) and are disposed in parallel with each
other are formed in another electrode sensor. When a finger of the
user is touches the display portion la of the light-transmissive
cover member 1, the electrostatic capacitance between an X
electrode and a Y electrode positioned below the touched portion is
changed so that the operation on the display portion la of the
light-transmissive cover member 1 in the touch panel 53 is
detected. The change in the electrostatic capacitance between the X
electrode and the Y electrode, which is generated in the touch
panel 53, is transmitted to the control unit 50, and the control
unit 50 specifies the content of the operation performed on another
surface 1B of the light-transmissive cover member 1 based on the
change in the electrostatic capacitance and performs an operation
according to the specified contents.
[0078] The piezoelectric vibrating element 55 is an element for
transmitting a reception sound to the user of the electronic
apparatus 100. The piezoelectric vibrating element 55 is vibrated
by a driving voltage applied from the control unit 50. The control
unit 50 generates a driving voltage based on a sound signal
indicating the reception sound and applies the driving voltage to
the piezoelectric vibrating element 55. The piezoelectric vibrating
element 55 is vibrated by the control unit 50 based on the sound
signal indicating the reception sound and thus the reception sound
is transmitted to the user of the electronic apparatus 100. In this
manner, the control unit 50 functions as a driving unit allowing
the piezoelectric vibrating element 55 to vibrate based on the
sound signal. The piezoelectric vibrating element 55 will be
described below in detail.
[0079] The external speaker 56 outputs a sound by converting the
electronic sound signal from the control unit 50 into the sound.
The sound output from the external speaker 56 is output to the
outside from speaker holes 20 provided on the rear surface 101 of
the electronic apparatus 100.
[0080] The microphone 57 outputs an electrical sound signalto the
control unit 50 by converting the sound input from the outside of
the electronic apparatus 100 into the electrical sound signal. The
sound from the outside of the electronic apparatus 100 is
incorporated in the electronic apparatus 100 from microphone holes
21 provided on the rear surface 101 of the electronic apparatus 100
and is input to the microphone 57.
[0081] The imaging unit 58 includes the imaging lens 58a, an
imaging element, and the like, and images a still image and a
moving image based on the control by the control unit 50.
[0082] The battery 59 outputs power of the electronic apparatus
100. The power output from the battery 59 is supplied with respect
to the respective electronic components contained in the control
unit 50 or the wireless communication unit 51 included in the
electronic apparatus 100.
[0083] <Details of Piezoelectric Vibrating Element>
[0084] FIGS. 9 and 10 are respectively a top view and a side view
illustrating a structure of the piezoelectric vibrating element 55.
As illustrated in FIGS. 9 and 10, the piezoelectric vibrating
element 55 has a long shape in one direction. Specifically, the
piezoelectric vibrating element 55 has a long and narrow
rectangular plate shape in a plan view. The piezoelectric vibrating
element 55 has, for example, a bimorph structure and includes a
first piezoelectric ceramic plate 55a and a second piezoelectric
ceramic plate 55b which are attached to each other through a shim
material 55c.
[0085] As illustrated in FIG. 11, in the piezoelectric vibrating
element 55, when a positive voltage is applied to the first
piezoelectric ceramic plate 55a and a negative voltage is applied
to the second piezoelectric ceramic plate 55b, the first
piezoelectric ceramic plate 55a extends along the longitudinal
direction and the second piezoelectric ceramic plate 55b contracts
along the longitudinal direction. Accordingly, as illustrated in
FIG. 11, the piezoelectric vibrating element 55 is bent into a
convex shape with the first piezoelectric ceramic plate 55a being
outside.
[0086] As illustrated in FIG. 12, in the piezoelectric vibrating
element 55, when a negative voltage is applied to the first
piezoelectric ceramic plate 55a and a positive voltage is applied
to the second piezoelectric ceramic plate 55b, the first
piezoelectric ceramic plate 55a contracts along the longitudinal
direction and the second piezoelectric ceramic plate 55b extends
along the longitudinal direction. Accordingly, as illustrated in
FIG. 12, the piezoelectric vibrating element 55 is bent into a
convex shape with the second piezoelectric ceramic plate 55b being
outside.
[0087] The piezoelectric vibrating element 55 vibrates while being
bent by alternatively taking the state of FIG. 11 and the state of
FIG. 12. The control unit 50 allows the piezoelectric vibrating
element 55 to vibrate while being bent by applying an AC voltage in
which the positive voltage and the negative voltage alternatively
appear at an area between the first piezoelectric ceramic plate 55a
and the second piezoelectric ceramic plate 55b.
[0088] FIGS. 10 to 12 illustrates one structure made of the first
piezoelectric ceramic plate 55a and the second piezoelectric
ceramic plate 55b which are bonded to each other by interposing the
shim material 55c therebetween in the piezoelectric vibrating
element 55. However, a plurality of the structures may be laminated
to each other.
[0089] <Arrangement Position of Piezoelectric Vibrating
Element>
[0090] FIG. 13 is a plan view when the light-transmissive cover
member 1 is seen from the first surface 1A side. The piezoelectric
vibrating element 55 is attached to the first surface 1A of the
light-transmissive cover member 1 using an adhesive such as a
double-sided tape. The piezoelectric vibrating element 55 is
arranged in a position which is not overlapped with the image
display device 52 and the touch panel 53 when the piezoelectric
vibrating element 55 is seen from side of the first surface 1A of
the light-transmissive cover member 1 in a plan view.
[0091] <Regarding Generation of Reception Sound Due to Vibration
of Piezoelectric Vibrating Element>
[0092] In the present embodiment, an air conduction sound and a
conduction sound are transmitted to the user from the
light-transmissive cover member 1 via the vibration of the
piezoelectric vibrating element 55. That is, the vibration of the
piezoelectric vibrating element 55 is transmitted to the
light-transmissive cover member 1 so that the air conduction sound
and the conduction sound are transmitted to the user from the
light-transmissive cover member 1.
[0093] Here, the term "air conduction sound" means a sound
recognized in a human brain by the vibration of an eardrum due to a
sound wave which enters an external auditory meatus hole (also
known as an "ear hole"). On the other hand, the term "conduction
sound" is a sound recognized in a human brain by the vibration of
the eardrum due to the vibration of an auricle transmitted to the
eardrum. Hereinafter, the air conduction sound and the conduction
sound will be described in detail.
[0094] FIG. 14 is a view for describing the air conduction sound
and the conduction sound. FIG. 14 illustrates a structure of an ear
of the user of the electronic apparatus 100. In FIG. 14, a wavy
line 400 indicates a conduction path of a sound signal of the air
conduction sound. A solid line 410 indicates the conduction path of
the sound signal of the conduction sound.
[0095] When the piezoelectric vibrating element 55 mounted to the
light-transmissive cover member 1 vibrates based on the electric
sound signal indicating the reception sound, the light-transmissive
cover member 1 vibrates and a sound wave is output from the
light-transmissive cover member 1. When the user moves the
light-transmissive cover member 1 of the electronic apparatus 100
close to an auricle 200 of the user by holding the electronic
apparatus 100 in a hand or the light-transmissive cover member 1 of
the electronic apparatus 100 is put to the auricle 200 of the user,
the sound wave output from the light-transmissive cover member 1
enters an external auditory meatus hole 210. The sound wave from
the light-transmissive cover member 1 enters in the external
auditory meatus hole 210 and the eardrum 220 vibrates. The
vibration of the eardrum 220 is transmitted to au auditory ossicle
230 and the auditory ossicle 230 vibrates. In addition, the
vibration of the auditory ossicle 230 is transmitted to a cochlea
240 and is converted into an electrical signal in the cochlea 240.
The electrical signal is transmitted to the brain by passing
through an acoustic nerve 250 and the reception sound is recognized
in the brain. In this manner, the air conduction sound is
transmitted from the light-transmissive cover member 1 to the
user.
[0096] When the user puts the light-transmissive cover member 1 of
the electronic apparatus 100 to the auricle 200 of the user by
holding the electronic apparatus 100 in a hand, the auricle 200 is
vibrated by the light-transmissive cover member 1 which is vibrated
by the piezoelectric vibrating element 55. The vibration of the
auricle 200 is transmitted to the eardrum 220, and thus the eardrum
220 vibrates. The vibration of the eardrum 220 is transmitted to
the auditory ossicle 230, and thus the auditory ossicle 230
vibrates. The vibration of the auditory ossicle 230 is transmitted
to the cochlea 240 and is converted into an electrical signal in
the cochlea 240. The electrical signal is transmitted to the brain
by passing through the acoustic nerve 250 and the reception sound
is recognized in the brain. In this manner, the conduction sound is
transmitted from the light-transmissive cover member 1 to the user.
FIG. 14 illustrates an auricular cartilage 200a in the inside of
the auricle 200.
[0097] In addition, the conduction sound herein is different from a
bone conduction sound. The bone conduction sound is a sound
recognized in a human brain by the vibration of the skull and
direct stimulation of the inner ear such as the cochlea caused by
the vibration of the skull. In FIG. 14, in a case of vibrating the
jawbone 300, the transmission path of the sound signal while the
bone conduction sound is recognized in the brain is indicated with
a plurality of arcs 420.
[0098] In this manner, in the electronic apparatus 100 according to
the present embodiment, the air conduction sound and the conduction
sound can be transmitted from the light-transmissive cover member 1
to the user of the electronic apparatus 100 due to the vibration of
the light-transmissive cover member 1 through the vibration of the
piezoelectric vibrating element 55. Since the user can hear a sound
when the user puts the light-transmissive cover member 1 to the
auricle 200 of the user, the communication using a telephone can be
performed without concerning the position of the electronic
apparatus 100 put against an ear so much. In addition, the user can
hear the conduction sound due to the vibration of the auricle, the
electronic apparatus 100 makes it easy for the user to hear the
sound even when there is a large amount of the ambient noise.
Accordingly, the user can appropriately perform communication using
a telephone even when there is a large amount of the ambient
noise.
[0099] In addition, even in a state in which earplugs or earphones
are fixed to the ears of the user, the reception sound from the
electronic apparatus 100 can be recognized by putting the
light-transmissive cover member 1 to the auricle. Further, even in
the state in which headphones are fixed to the ears of the user,
the reception sound from the electronic apparatus 100 can be
recognized by putting the light-transmissive cover member 1 to the
headphones.
[0100] <Regarding Holes of Ear Piece (Holes for
Receiver)>
[0101] In the electronic apparatus 100 according to the present
embodiment, since the reception sound is generated by the vibration
of the light-transmissive cover member 1, the reception sound can
be appropriately transmitted to the user even through there are no
holes in the ear piece of the light transmissive cover member 1.
Therefore, production costs can be reduced because the laser
processing cost associated with making such holes is no longer
needed. Further, since the light-transmissive cover member 1 has no
holes in the ear piece, the strength of the light-transmissive
cover member 1 is higher than it would be if the light-transmissive
cover member 1 had holes in the ear piece. Furthermore, in the
present embodiment, since there are no holes of the ear piece on
the surface of the electronic apparatus 100, the problem of water
or dust entering the holes of the ear piece is eliminated.
Therefore, the necessity for a water-proof structure or a
dust-proof structure along with the cost of such structures is
reduced.
[0102] In the above-described embodiment, a case of a mobile phone
to which the present invention is applied is described. However,
the present invention can be applied to an electronic apparatus
other than the mobile phone. For example, embodiments may be
applicable to tablet terminal, e-readers, digital cameras, video
game consoles, digital music players, personal digital assistants
(PDA), personal handy phone system (PHS), laptop computers,
portable TV's, Global Positioning Systems (GPS's) or navigation
systems, machining tools, pedometers, health equipment such as
weight scales, display monitors, smartwatches, and the like. In
addition, the present invention is not limited to the
above-described embodiments, and various modifications and changes
may be made in the range not departing from the scope of the
present invention.
* * * * *