Touch switch with thermo-chromatic layers

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an input device and an electronic apparatus having such an input device capable of providing visual amusement at the time of operating thereof.

2. Description of Related Art

In input devices such as key switch, touch switch and touch panel operated by finger touch, feedback for the input operation largely depends on tactual sense of a finger. A key switch is an only input device ever known to be integrated with a visual feedback indicator, in which color change is effected by incorporating a self-light-emitting element so as to be active in response to the ON/OFF operation of such switch, or by providing a mechanical shutter so as to cover/uncover the color-coated inner surface.

The touch panel is often mounted as a single-function device to electronic apparatus and examples of which, as combined with visual feedback display devices, include computer display and liquid crystal display.

The conventional switch is, however, disadvantageous in that feedback depending on the tactual sense cannot readily be obtained with a thinned switch due to a limited displacement in response to the input operation.

A problem also resides in that incorporating the foregoing visual feedback display device into a small-sized apparatus will also require relevant electronic circuits, wirings and contact portions, which may be an obstacle to the thinning, weight reduction and power saving.

Another problem resides in that, for a case of using a display device, a CPU (central processing unit) affording a certain level of high-speed processing will be required for ensuring real-time feedback display, which is disadvantageous in terms of cost, power consumption and heat generation.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to solve the foregoing problem and to provide an input device allowing the down sizing and thinning, and providing visual amusement at the time of operating thereof, and to provide an electronic apparatus having such an input device.

According to the first aspect of the present invention, there is provided an input device which comprises:

a reversible chromatic layer exhibiting color change in response to temperature change; and

a sheet-type input portion laminated on the reversible chromatic layer and activates ON operation upon being pressed.

Since the reversible chromatic layer causes color change simply by pressing the sheet-type input portion in the ON operation, visual change is enjoyable while achieving the down sizing and thinning.

In the second aspect of the present invention, the input device having the above first feature is characterized in that the reversible chromatic layer is located on a front surface of the sheet-type input portion and an input operation is effected by direct contact with such reversible chromatic layer.

When operating such an input device, the user directly touches the reversible chromatic layer.

In the third aspect of the present invention, the input device having the above first feature is characterized in that the reversible chromatic layer is located on a rear surface of the sheet-type input portion and an input operation is effected by direct contact with such sheet-type input portion.

When operating such an input device, the user directly touches the sheet-type input portion.

In the fourth aspect of the present invention, the input device having the above second feature is characterized in that heat required to cause temperature change of the reversible chromatic layer is provided through the direct contact thereto with a part of a human body.

That is, heat required to cause temperature change of the reversible chromatic layer is simply provided by a human touch.

In the fifth aspect of the present invention, the input device having the above third feature is characterized in that heat required to cause temperature change of the reversible chromatic layer is provided from an inner portion of an electronic apparatus.

That is, heat generated in the inner portion of the electronic apparatus can be consumed for causing temperature change in the reversible chromatic layer.

According to the sixth aspect of the present invention, there is provided an electronic apparatus having an input device, and the input device comprises:

a reversible chromatic layer exhibiting color change in response to temperature change; and

a sheet-type input portion laminated on the reversible chromatic layer and activates ON operation upon being pressed.

In such constitution, the reversible chromatic layer causes color change in response to the temperature change thereof. The sheet-type input portion is provided as laminated on the reversible chromatic layer, and can activate the ON operation simply by being pressed.

This allows color change of the reversible chromatic layer simply by pressing the sheet-type input portion in the ON operation, and can provide the user with visual amusement at the time of the ON operation of such an input device.

In the seventh aspect of the present invention, the electronic apparatus having the above sixth feature is characterized in that the reversible chromatic layer is located on a front surface of the sheet-type input portion and exposed outward within a window provided to a housing of the electronic apparatus, and

an input operation is effected by direct contact with such reversible chromatic layer.

When operating such an input device, the user directly touches the reversible chromatic layer.

In the eighth aspect of the present invention, the electronic apparatus having the above sixth feature is characterized in that the sheet-type input portion is exposed outward within a window provided to a housing of the electronic apparatus, the reversible chromatic layer is located on a rear surface of such sheet-type input portion, and an input operation is effected by direct contact with such sheet-type switch portion.

When operating such an input device, the user directly touches the sheet-type input portion.

In the ninth aspect of the present invention, the electronic apparatus having the above seventh feature is characterized in that heat required to cause temperature change of the reversible chromatic layer is provided through the direct contact thereto with a part of a human body.

That is, heat required to cause temperature change of the reversible chromatic layer is simply provided by a human touch.

In the tenth aspect of the present invention, the electronic apparatus having the above eighth feature is characterized in that heat required to cause temperature change of the reversible chromatic layer is provided from an inner portion of an electronic apparatus.

That is, heat generated in the inner portion of the electronic apparatus can be consumed for causing temperature change in the reversible chromatic layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view showing a preferred embodiment of an input device and an electronic apparatus having such an input device according to the present invention;

FIG. 2

is a sectional view of the electronic apparatus taken along the line II—II in

FIG. 1

;

FIG. 3

is a sectional view of the electronic apparatus taken along the line III—III in

FIG. 1

;

FIG. 4

is an enlarged view of the input device and so forth;

FIG. 5

is an enlarged view of the input device and so forth as viewed form another angle;

FIGS. 6A and 6B

are views showing an exemplary color change caused by a finger placer on the reversible chromatic layer;

FIGS. 7A and 7B

are views showing an exemplary color change caused by a finger sliding on the reversible chromatic layer;

FIG. 8

is a sectional view showing another embodiment of the input device and the electronic apparatus having such an input device according to the present invention taken along the line VIII—VIII in

FIG. 1

;

FIG. 9

is a sectional view showing another embodiment of the electronic apparatus taken along the line IX—IX in

FIG. 1

;

FIG. 10

is an enlarged view of the input device and so forth;

FIG. 11

is an enlarged view of the input device and so forth as viewed form another angle;

FIGS. 12A and 12B

are views showing another embodiment of the present invention;

FIGS. 13A and 13B

are views showing still another embodiment of the present invention;

FIG. 14

is a block diagram showing an exemplary internal structure of the electronic apparatus shown in

FIG. 1

;

FIG. 15

is a diagram showing an exemplary connection of the input device, a microcomputer and so forth;

FIG. 16

is a flow chart showing an exemplary key input operation;

FIG. 17

is a drawing showing ax exemplary input key code decision table; and

FIG. 18

is a drawing showing an exemplary input key code decision sequence.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be explained in detail hereinafter referring to the attached drawings.

The embodiments described hereinafter are preferred specific examples of the present invention, so that they will appear with various technically preferable limitations. It is, however, to be understood that the scope of the present invention is not restricted at all to the embodiments unless otherwise being specifically noted.

FIG. 1

shows a preferable embodiment of an electronic apparatus equipped with an input device of the present invention.

An electronic apparatus

10

allows the user to enter a desired command by gently pressing a switch

18

with the finger F. The electronic apparatus

10

in this embodiment is typified as a portable music reproducing apparatus for replaying music information, and replays the music information when the user enters a predetermined command.

The electronic apparatus

10

has a housing (case)

12

and the switch

18

.

The housing

12

comprises an upper housing portion

14

and a lower housing portion

16

, arid is made of, for example, a plastic or a metal. For a case where the housing

12

is made of a plastic, available plastics include ABS (acrylonitrile-butadiene-styrene), ABS-PC (acrylonitrile-butadiene-styrene-polycarbonate), PA (polyamide), PC (polycarbonate), LCP (liquid crystal polymer) and the like. For a case where the housing

12

is made of a metal, available metals include Mg alloy, Al alloy, Zn alloy and the like.

On an end plane

26

of the housing

12

shown in

FIG. 1

, an output portion

92

is provided. By connecting a plug

92

B of a stereo earphone

92

A to the output portion

92

, the user can enjoy the music stored in a memory

86

through the stereo earphone

92

A. On an opposite end plane

28

of the housing

12

, an interface portion

22

is provided. By connecting, for example, an external computer

93

to the interface portion

22

, the user can download the music information IN from the computer

93

into the internal memory

86

accommodated in the housing

12

.

FIG. 2

shows a sectional view of the electronic apparatus

10

taken along the line II—II in

FIG. 1

, and

FIG. 3

shows a sectional view taken along the line III—III in FIG.

1

.

As shown in

FIGS. 2 and 3

, a switch

30

, a circuit board

170

and a battery

180

and the like are accommodated in a space surrounded by the upper housing portion

14

and the lower housing portion

16

of the housing

12

.

The battery

180

is exemplified as a nickel-cadmium battery, nickel-hydrogen battery, lithium ion secondary battery or lithium-polymer battery, and is fixed on the bottom of the lower housing portion

16

.

The circuit board

170

has a plurality of electronic parts

171

,

172

mounted thereon. The electronic parts

171

,

172

are, for example, a driver and a CPU, both of which are causative of heat generation during the operation. The circuit board

170

is electrically connected to the output portion

92

and interface portion

22

shown in FIG.

1

.

The switch

30

is located so as to aligne with a slit portion

40

of the upper housing portion

14

, and most part of the switch

30

is exposed outward within the slit portion

40

. This allows the finger F to directly touch the most part of the switch

30

. When directly touching the switch

30

, the user can move the finger F along the direction X

1

or X

2

indicated in FIG.

1

.

FIGS. 4 and 5

show enlarged views of the laminated structure shown in

FIGS. 2 and 3

.

The switch

30

comprises a reversible chromatic layer

60

, a sheet-type switch portion

62

and a heat-insulating layer

64

laminated and adhered with each other. The heat-insulating layer

64

is responsible for preventing heat generated by the electronic parts

171

,

172

on the circuit board

170

from conducting toward the reversible chromatic layer

60

.

The reversible chromatic layer

60

is a layer comprising a substance, the spectrum of which changes at least in the visible light region in response to temperature change within a certain range, which is also known as a reversible thermochromic substance or the like.

The following materials are used for the reversible chromatic layer

60

.

The reversible chromatic layer

60

comprises a substance exhibiting thermochromism and is available for heat sensitive display. Thermochromism refers to a phenomenon such that a color is not observed at a certain temperature but develops under proper heating, or such that a color is observed at the normal temperature but fades or changes into another color as the temperature rises.

As such a substance used for the reversible chromatic layer

60

, conventionally used is such that liberates water under heating to cause color change and re-absorb the water under cooling to recover the initial color. Specific examples of such a substance include double salts comprising transition metals such as cobalt, nickel and manganese as combined with amine amides such as hexamethylene tetramine; mercury iodide; double complex salts comprising mercury iodide and other metal iodide; heavy metal compounds such as lead chromate and ammonium metavanadate; organic compounds such as dixanthilene and bianthrone; and certain kinds of organic dyes and pigments.

Other known thermochromic substances available for the reversible chromatic layer

60

include cholesteric liquid crystal, or mixture of cholesteric and nematic liquid crystals.

A heat sensitive chromatic agent is recently developed and widely used; the agent comprising an electron donor substance developing it color by releasing an electron and an electron acceptor substance (electron accepting developer) mixed therewith.

Known electron accepting developers include phenols, phenol resin oligomer, organic acids such as oxyaromatic carboxylic acids, acidic substances such as zinc chloride and stannous chloride, and adsorbents such as attapulgite and montmorillonite.

There are no specific limitations on the electron donating coloring substance and any known substance may arbitrary be selected, provided that it can allow reversible color change between a dark color and perfect colorless. Specific examples thereof include substituted phenylmethane and fluorane derivatives such as 3,3′-dimethoxyfluorane (yellow), 3,3′-dibutoxyfluorane (yellow), 3-chloro-6-phenylaminofluorane (yellowish orange), 3-diethylamino-6-methylchlorofluorane (reddish orange), 3-diethyl-7,8-benzofluorane (pink), 3,3″,3″-tris(p-dimethylaminophenyl)phthalide (bluish purple), 3,3″-bis(p-dimethylaminophenyl)phthalide (green), 3-diethylamino-7-dibenzylaminofluorane (dark green), 3-diethylamino-6-methyl-7-phenylaminoflorane (black); various indolyl phthalide-base dye (blue to green); and spiropyranes (yellowish brown to reddish green). These compounds may be used independently of in combination of two or more thereof.

There are no specific limitations also on the electron accepting developer and any known substance may arbitrary be selected. Specific examples thereof include phenols, oxyaromatic carboxylic acid, carboxylic acid, azoles, azole esters, azole amides, aid metal salts thereof such as lithium salt, sodium salt, calcium salt, magnesium salt, aluminum salt, zinc salt, tin salt, titanium salt and nickel salt. These compounds may be used independently or in combination of two or more thereof.

In the switch

30

, which is also referred to as an input apparatus, a paint exhibiting reversible thermochromism is coated in an area coming into direct contact with the finger F. The thermochromic coloring agents include organic phosphor, metal complex solution and chiral nematic liquid crystal, all of which can vary the light emission spectrum in response to temperature. These coloring agents are mixed with an auxiliary of petroleum-base, ester-base, ketone-base or aromatic-base, and coated using a spray gun or brush.

The auxiliary is selected optimally depending on the material composing the switch contact portion to be coated therewith. Thickness of the coated paint is closely related to the temperature rise through heat conduction, so that a thickness allowing a sufficient chromatic effect is preferable. The temperature range allowing the color change is preferably selected so that a first color in the lower temperature region is developed at the temperature of the housing or other peripheral portions, and that a second color in the higher temperature region is developed at the temperature within an area around the site of the finger touch at the time of such finger touch. It is now necessary to properly select the coloring agent and the auxiliary depending on the environment in which they are used, since the above temperature may vary depending on such environment of use.

With such an input device involving the coated layer, an input operation is effected by a direct touch by the user's finger F, heat require for the temperature change of the reversible chromatic layer

60

will be provided through heat conduction toward the coated plane, and the temperature within an area around the site of the finger touch will rise to develop the color change in such area.

As shown in

FIGS. 4 and 5

, the reversible chromatic layer

60

is laminated on the front surface (top surface) of the switch

30

by printing or coating with a brush or spray gun, or integrated with an upper sheet

62

A or a lower sheet

62

B by kneading.

The sheet-type switch portion

62

has the upper sheet

62

A susceptible of elastic deformation upon a gentle touch with the finger F, the lower sheet

62

B and spacers

62

C. The spacers

62

C contribute to maintain a space SP between the upper sheet

62

A and lower sheet

62

B, and in the space SP electrodes

63

A and

63

B are housed. The upper sheet

62

A, lower sheet

62

B and spacers

62

C are made of an insulating material such as biaxially stretched PET (polyethylene terephthalate) film, uniaxially stretched PET film, PC (polycarbonate) film or PES (polyether sulfone) film.

The switch

30

has switch contact points

50

to

54

regularly spaced as shown in FIG.

1

.

FIG. 4

typically shows an exemplary constitution of the switch contact point

50

and the adjacent switch contact point

51

. The structures of electrodes

63

A and

63

B are the same for all switch contact points

50

to

54

.

The electrodes

63

A and

63

B are made of, for example, Ag—C, C or Cu.

Next, an exemplary operation of the switch (also referred as to the input device) and the electronic apparatus having such switch previously shown in

FIGS. 1

to

5

will be described referring to

FIGS. 6A

,

6

B,

7

A and

7

B.

FIGS. 6A and 6B

show an exemplary state in which the finger F is placed on the reversible chromatic layer

60

. The reversible chromatic layer

60

exhibiting reversible thermochromism causes temperature rise upon placing of the finger F due to the body temperature conducted therefrom, which results in changes in the light emission spectrum of the reversible chromatic layer

60

.

FIGS. 6A and 6B

shows the color change occurred at a finger-contacted portion

60

R and adjacent portions

60

S,

60

T.

FIGS. 7A and 7B

show an exemplary state in which the finger F is slid in the direction X

1

along the reversible chromatic layer

60

. As shown in the figures, the color change is observed in the adjacent portions

60

S where the finger F just went by.

In such a manner, the user can activate ON operation of any one of, or an arbitrary combination of the switch contact points

50

to

54

by sliding the finger F on the reversible chromatic layer

6

C of the switch

30

shown in

FIGS. 1 and 2

in the directions X

1

or X

2

shown in

FIG. 1

, while enjoying the color change. Pressing an arbitrary one from the switch contact points

50

to

54

allows the electrodes

63

A and

63

B shown in

FIG. 4

to come into an electric contact by force of the finger F. Thus the user can activate the ON operation of an arbitrary one of the switch contact points

50

to

54

.

Another exemplary embodiment of the switch and the electronic apparatus having such switch of the present invention will be described referring to

FIGS. 8

to

11

.

The switch and the electronic apparatus shown in

FIGS. 8 and 9

differ from those shown in

FIGS. 2 and 3

in the constitution of a switch

130

.

The switch

130

does not have the heat-insulating layer

64

, unlike the embodiment shown in

FIG. 4

, and has only the sheet-type switch portion

62

and reversible chromatic layer

60

as shown in

FIGS. 10 and 11

.

The heat insulating layer

64

in the foregoing embodiment shown in

FIG. 4

was composed so as to blocking the heat conducted from the electronic parts

171

on the circuit board

170

, so that the reversible chromatic layer

60

can change color solely by the heat conducted from the finger F. That is, the heat required for the color change of the reversible chromatic layer

60

was directly obtained from the finger F as a part of the user's body.

On the contrary in the embodiment shown in

FIGS. 8 and 10

, the reversible chromatic layer

60

is placed as opposed to the electronic parts

171

mounted on the circuit board

170

. That is, the reversible chromatic layer

60

is provided by coating or printing, or fixed by adhesion underneath, that is, on the rear plane of the lower sheet

62

B of the sheet-type switch portion

62

.

Since the reversible chromatic layer

60

is provided on the rear side of the sheet-type switch portion

62

comprising the upper sheet

62

A, spacers

62

C and lower sheet

62

B as shown in

FIG. 10

, it is preferable for the user to enjoy the color change that the upper sheet

62

A, spacers

62

C and lower sheet

62

B comprising the sheet-type switch portion

62

, and preferably also the electrodes

63

A,

63

B, are transparent.

In this case, the upper sheet

62

A, the lower sheet

62

B and the spacers

62

C are individually made of, for example, a transparent material, and specific examples of which include a uniaxially stretched PET film, PC film and PES film. Also the electrodes

63

and

63

B are preferably made of a transparent material such as ITO (indium tin oxide; In

2

O

3

—SnO

2

) obtained by sputtering, vapor deposition, ion plating or CVD (chemical vapor deposition); ATO (antimony tin oxide; SnO

2

—Sb

2

O

5

); CTO (cadmium tin oxide; Cd

2

SnO

4

); SnO

2

; ZnO—SnO

2

; and CdO—ZnO—SnO

2

.

The reversible chromatic layer

60

shown in

FIG. 10

is designed to obtain heat necessary for the color change from the electronic parts

171

mounted on the circuit board

170

. That is, heat generated by the electronic parts

171

on the circuit board

170

during the operation is directly used as a heat source for the temperature change of the reversible chromatic layer

60

.

Since other parts of the switch and the electronic apparatus incorporating such switch shown in

FIGS. 8

to

11

are the same as those shown in

FIGS. 2

to

5

, the same marks will be used in

FIGS. 8

to

11

while omitting the description therefor.

In the embodiment shown in

FIGS. 8

to

11

, the user can activate ON operation of any one of, or an arbitrary combination of the switch contact points

50

to

54

by sliding the finger F, for example, in the directions X

1

or X

2

shown in FIG.

1

. When a force is applied through the finger F to the switch contact points

50

to

54

of the sheet-type switch portion

62

, a slight amount of heat from the finger F will conduct to the reversible chromatic layer

60

and cause the color change thereof so as to trace the movement of the finger F.

FIGS. 12A and 12B

show another embodiment of the present invention.

The reversible chromatic layer

60

shown in

FIGS. 12A and 12B

is formed by coating two or more separate paint having different temperature-dependent chromatic characteristics. The reversible chromatic layer

60

shown in

FIGS. 12A and 12B

is obtained by, for example, coating in a repetitive manner reversible chromatic substance patterns

60

A,

60

B and

60

C differing with each other in the temperature-dependent chromatic characteristics. This allows exhibition of different color change depending on the site of the finger touch on the reversible chromatic layer

60

of the switch

30

.

When different kinds of reversible chromatic substances are coated, masking with masking tape or so can allow a specific kind of the substance to be coated only to the limited area, and repeating such process by numbers of substances will provide such different color change as shown in

FIGS. 12A and 12B

FIG. 12A

shows a state where different kinds of reversible chromatic substances are coated, and

FIG. 12B

shows an example of different color change after actual finger touch.

FIGS. 13A and 13B

show still another embodiment of the present invention.

As shown in

FIG. 13A

, the reversible chromatic layer

60

of the switch

30

has an area

60

V in which a paint having a certain temperature-dependent chromatic characteristic is coated, and has an area

60

W in which a paint having a different temperature-dependent chromatic characteristic is coated. The area

60

W has a pattern of letters “X”, “Y” and “Z”. Such constitution allows, as shown in

FIG. 13A

, the letters “X”, “Y” and “Z” to emerge in the area

60

W in response to the finger touch from the invisible state.

Or, as shown in

FIG. 13B

, it is also possible to coat a paint having a certain temperature-dependent chromatic characteristic in an area

160

V and coat a paint having a different temperature-dependent characteristic in an area

160

W, thereby to provide an visual effect such that a faint display of the letters “X”, “Y” and “Z” becomes a more recognizable display.

With such patterning of the letters based on the masking technique as shown in

FIGS. 13A and 13B

, various characters can be emerged by the finger touch. The cases shown in

FIGS. 12A

,

12

B,

13

A and

13

B are also applicable to the embodiment shown in

FIGS. 1 and 11

.

Using thus aligned switch

18

shown in FIG.

1

and providing the foregoing coating on the touch plane allow the color change by finger touch not only in a single press, but also in a sliding manner as shown in FIG.

1

. Providing a proper delay period in the color change will allow the chromatic effect to be sustained in an area behind the finger passage.

It has been thought in the conventional art that providing a visual feedback display device to an input device such as a keyboard or touch panel was disadvantageous in terms of power consumption and complicated mechanism. Whereas the present invention is successful in the thinning, down sizing and the feedback without additional power consumption, so that down sizing and power saving of the electronic apparatus can be achieved while providing amusement through the visual effect.

Possible styles of the switch include those having aligned switches, and more specifically include a touch panel, serially-aligned planar press switch and matrix-aligned planar press switch.

According to the present invent ion, an extra-thin switch, feedback of which being not dependent only on the tactual sense, can be fabricated. Using such extra-thin switch results in reduction in the size and weight of the electronic apparatus.

Since the chromatic effect can be obtained without additional power consumption, the electronic apparatus can be used for a long period while suppressing the exhaustion of the battery.

In addition, the visual effects can provide the user with amusement in the input operation through such switch.

The present invention is by no means limited to the foregoing embodiments.

While

FIG. 1

shows a portable music information reproducing apparatus as an exemplary electronic apparatus having the switch of the present invention, the electronic apparatus of the present invention is not limited to such apparatus and also covers a display or other type of apparatuses.

The switch and the electronic apparatus of the present invention allows down sizing and thinning of the electronic apparatus, and provides the user with amusement of visual effect in the feedback without additional power consumption.

FIG. 14

shows an exemplary electrical connection between the switch

18

and the individual components of the electronic apparatus

10

previously shown in FIG.

1

. In the housing

12

, provided are a microcomputer

80

dedicated for key input, a microcomputer

84

for general control, a memory

86

for storing, for example, arbitrary music information, and a music information amplifying output portion

88

.

The microcomputers

80

and

84

, the memory

86

and the music information amplifying output portion

88

composes a circuit unit

90

, and the circuit unit

90

is located in an inner space of the housing

12

.

The microcomputer

80

is connected to the switch contact points

50

to

54

of the sheet-type switch portion

62

previously shown in FIG.

2

.

The microcomputer

80

is also connected to the microcomputer

84

for general control. The memory

86

is connected to the microcomputer

84

for general control. The microcomputer

84

controls the microcomputer

80

, memory

86

and music information amplifying output portion

88

.

The microcomputer

84

is connected to the music information amplifying output portion

88

. The music information amplifying output portion

88

amplifies music information received from the memory

116

via the microcomputer

84

and then outputs the information to the output portion

92

such as a headphone or earphone. Using the output portion

92

makes the music information audible to the user.

The information output from the output portion

92

may of course not only be the music information but also be other type of audio information.

A semiconductor memory, for example, and any other type of memory are applicable as the memory

86

. The memory

86

may be fixed to the circuit unit

90

, or may be composed so as to be detachable from the circuit unit

90

. It is also possible to directly writ music or other information through a communication network such as Internet.

Available semiconductor memories include DRAM (dynamic random access memory) and SRAM (static random access memory). Hard disk is a typical example of other type of memory.

FIG. 15

shows an exemplary connection between the microcomputer

80

and switch contact points

50

to

54

previously shown in FIG.

14

. In

FIG. 15

, the switch contact points

50

to

54

are denoted as key

0

to key

4

.

The switch contact points

50

to

54

are individually connected via wirings

66

to ports P

10

to P

14

of the microcomputer

80

as shown in FIG.

15

. Port P

20

of the microcomputer

80

is connected to a common electrode

68

for the switch contact points

50

to

54

.

It is also allowable to design an output portion

87

of the microcomputer

80

so as to output a voltage corresponding to an input key code decided by internal processing of a microcomputer

80

. Examples of such key codes and the relevant output voltage ratio are listed in Table (A) in FIG.

15

.

Input key code VOL+ in Table (A) in

FIG. 15

enables raising of the sound level from the music information amplifying output portion

88

shown in

FIG. 14

, the corresponding output voltage ratio being 0.5. Input key code VOL− enables lowering of the sound level, the corresponding output voltage ratio being 0.57.

Input key code STOP stops replay of music information, the corresponding output voltage ratio being 0.59. Input key code PLAY/FF enables transfer of music information from the memory

86

, shown in

FIG. 14

, to the output portion

92

and feed-forward of the music information, the corresponding output voltage ratio being 0.73. Input key code REW enables recovering the replay position of music information from the memory

86

, shown in

FIG. 14

, the corresponding output voltage ratio being 0.9.

Now the output voltage ratio is defined as

output voltage=output voltage ratio×Vcc

where, Vcc is a reference voltage and is typically 5 V.

FIG. 16

shows an exemplary key input operation for the input device

18

previously shown in

FIGS. 1

to

3

.

FIG. 17

shows an exemplary input key code decision table.

For example, if a key input is detected in step ST

100

in

FIG. 16

, which is actually done by the switch contact points

50

to

54

in

FIG. 2

, an input key code listed in

FIG. 17

is set in step ST

120

.

The exemplary input key code decision table of

FIG. 17

shows key (switch contact point) initially turned ON in Column (A), current ON key in Column (B) and applied input key code in Column (C).

The input key code decision tab e of

FIG. 17

also has Rows (D), (E) and (F).

Rows (D) shows various key codes defined by combinations of the key initially turned ON in Column (A) and the current ON key in Column (B). For example, when the key initially turned ON is key

0

and current ON key defined within a predetermined period is again key

0

, that is, when the same key was pressed twice within a predetermined period, the input key code will be VOL+ (raising sound level).

When the key initially turned ON is key

1

and current ON key defined within a predetermined period is again key

1

, the input key code will be invalid. Similarly, key

3

for the key initially turned ON and key

3

for the current ON key defined within a predetermined period will also result in an invalid input key code.

Key

2

for the key initially turned ON and key

2

for the current ON key defined within a predetermined period will result in an input key code of STOP (cessation of replay of music information); and key

4

for the key initially turned ON and key

4

for the (current ON key defined within a predetermined period will result in an input key code of VOL− (lowering sound level).

Rows (E) of

FIG. 17

correspond to the cases in which an input key code PLAY/FF is generated when the key initially turned ON and the current ON key defined within a predetermined period are different a with each other. For example, when the key initially turned ON is key

0

and the current ON key defined within a predetermined period is key

0

, the input key code will be PLAY (replay operation of music information)/FF (feed-forward to replay position of music information)

While Rows (E) correspond to the cases in which the key initially turned ON is smaller than the current ON key, Rows (F) on the contrary corresponds to the cases in which the key initially turned ON is larger than the current ON key. In these cases, the input key code will be REW (recovering replay position of music information). For example, when the key initially turned ON is key

4

and the current ON key defined within a predetermined period is key

3

, the input key code will be REW.

FIG. 18

shows an exemplary input key code decision sequence.

In the key scan shown in Column (A) of

FIG. 18

, the microcomputer

80

previously shown in

FIG. 15

scans the ports P

10

to P

14

to detect ON state thereof, and sets those in the ON state as the initially ON keys.

Of course, chattering elimination, noise isolation and other software-base processing internally proceed at that time so as to avoid false recognition of pressing the key despite no human intention of pressing the key, or to avoid false judgment of pressing the key interfered by external electromagnetic noise.

Thereafter, the switch will be pressed again according to the modes shown in Columns (B) to (D) of

FIG. 18

, that is, any key will be pressed within a predetermined period.

When the same key is pressed within a predetermined period as described in Column (B) of

FIG. 18

, the input key codes shown in Rows (D) of

FIG. 17

will come into effect.

When the adjacent key is turned in to ON, the input key code PLAY/FF or REW will come into effect according to the combination listed in Rows (E) and (F) of FIG.

17

.

Column (D) of

FIG. 18

indicates other key operation, in which a current ON key is set as an initially ON key while ignoring the function of a key initially turned ON. One typical case relates to that the current ON key shown in Column (A) of

FIG. 17

is pressed after an elapse of a predetermined period after pressing the key initially turned ON.

Next, an exemplary operation of the input device

18

previously shown in

FIGS. 1

to

3

will be detailed.

As shown in

FIG. 1

, the user serially presses the switch contact points

50

to

54

with the finger F by scanning along the longitudinal direction X

1

of the slit portion

40

or the counter direction X

2

; or presses only any one switch contact point.

In this case, the slit portion

40

shown in

FIGS. 2 and 3

can correctly guide the pad of the finger F towards the switch contact points

50

to

54

, which allows the user's finger surely touch the contact point

50

to

54

. Since the slit portion

40

can support a part of the finger pad, the finger pad will never exert an unnecessary force on the sheet-type switch portion

62

, which will successfully prevent properties of the sheet-type switch portion

62

and the switch contact points

50

to

54

from being degraded.

For example, when the user presses the switch contact point

50

for operation shown in

FIG. 1

a plural times, for example, twice, within a predetermined period, the microcomputer

80

shown in

FIG. 15

will send a control signal representing the input key code VOL+ to another microcomputer

84

shown in

FIG. 14

according to the description in Rows (D) of FIG.

17

. The microcomputer

84

will send a control signal to the music information amplifying output portion

88

, which will raise the sound level of the music information output from the output portion

92

.

When the user presses, for example, the switch contact point

50

(key

0

) for operation and then presses the switch contact point

51

(key

1

) for operation within a predetermined period, the input key code of PLAY/FF will come into effect as shown in Rows (E) of

FIG. 17

, and a control signal for PLAY/FF will be sent from the microcomputer

80

to the microcomputer

84

shown in FIG.

14

. Thus the music information stored in the memory

86

will be replayed from the output portion

92

with the aid of the microcomputer

84

, or replay position thereof will be fed forward. The feed forward operation allows search for the beginning of the next title.

When the user presses, for example, the switch contact point

54

(key

4

) for operation and the switch contact point

53

(key

3

) for operation within a predetermined period, the input key code of REW will come into effect by the microcomputer

80

as shown in Rows (F) of

FIG. 17

, and a control signal for REW will be sent from the microcomputer

80

to the microcomputer

84

shown in FIG.

14

. Thus the microcomputer

84

will recover a certain replay position of the music information stored in the memory

86

.

As described in the above, when the user serially touches by the finger an arbitrary number of key tops from the switch contact points

50

to

54

, complete touch will be effected simply by sliding the finger along the longitudinal direction X

1

of the slit portion

40

or along the counter direction X

2

. Moreover, only a limited number of switch contact points

50

to

54

for operation can afford selection of various functions as listed in

FIG. 17

by a simple operation with the user's finger. An input key code decision table available in such use can be displayed, for example, on the rear plane of the housing

12

shown in FIG.

1

.

The present invention is by no means limited to the foregoing embodiments and permits various modifications.

The microcomputers

80

and

84

shown in

FIG. 14

can be integrated into a single microcomputer.

The input device

18

shown in

FIG. 1

is provided for an electronic apparatus, and more specifically for a portable music reproducing device. A music reproducing device including such an input device may be of hand-held type, arm-held type, pendant type or of other types.

The input device of the present invention can be applicable not only to such an electronic apparatus for replaying music or music information, but also to a recording and reproducing apparatus for music information. The input device of the present invention still can be applicable not only to recording and reproducing of music information, but also to recording and reproducing apparatus of image and audio information, or to reproducing apparatus of image and audio information.

The input device of the present invention can still further be applicable to electronic apparatus of other types or in other fields besides the applications described above. For example, applying the input device to a touch pad intended for character input will allow the user to proceed current input operation while confirming the locus of the input operation finished immediately before or a few seconds before. Thus a character of much strokes such as some kinds of Chinese characters can be input while confirming a relative positioning of a radical, and input error will be avoidable.

According to the embodiment of the present invention, conventional problems can be overcome by employing the feedback based on the visual sense in place of that based on the tactual sense.

A display using the feedback based on such visual effect is composed of a thin plate or thin film provided on the switch, which exhibiting the color change in response to the user's operation and more specifically to the motion of the switch. Such color change automatically recovers the initial state immediately after or within a proper delay period after the completion of the input operation, so that sufficient opportunities for confirming the input operation and enjoying the visual effects are given to the user.

By providing such chromatic mechanism to an input device such as a keyboard, touch switch or touch pad so as to be added to the top surface thereof or integrated with the input device, the color change upon the input operation will be obtained.

Employing a highly transparent material for the input device, in addition to such chromatic mechanism, allows the mechanism to be placed on the display device, which results in functional integration of the input and display devices and down sizing of the electronic apparatus.

The intentional introduction of the local difference in the chromatic effect to an area exhibiting the chromatic function can sufficiently provide the user with amusement in the operation.

If such chromatic mechanism is made detachable so as to allow the user to exchange it to his or her own taste, the user can also show the individuality.