Display apparatus and electronic watch using the display apparatus

A display apparatus is provided with a display member which is printed in gradations of color from a first color to a second color from one side of the member to other side, and an electro-optical display device having plural dot display sections disposed on the display member. The plural dot display sections are selectively driven, to display characters, images, etc. in gradations of color. The display apparatus which is simple in structure and low in manufacturing cost advantages to improve image and/or character discrimination and is used for an adornment purpose.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display apparatus for displaying characters and images in gradations of color and an electronic watch using such display apparatus.

2. Description of the Related Art

As disclosed in Japanese laid-open patent publication No. hei8-220263 and Japanese laid-open patent publication No. sho57-101788, an electronic watch has been proposed, which uses a dot matrix display apparatus for the purposes of improving image and/or character discrimination and for an ornament purpose.

In a conventional electronic wrist watch, a monochrome liquid crystal display device is used to display characters and images. Therefore, such electronic watch is monotonous in design and poor in ornament, and has a problem to be solved in character discrimination. A color liquid crystal display device used in the electronic watch will improve character discrimination and may be used by way of ornament to the electronic watch, but has another problems that such watch will be expensive and the display device will consume much more power, resulting in a short battery life.

SUMMARY OF THE INVENTION

The present invention has been made to solve the conventional problems set forth above, and has an object to provide a display apparatus which is inexpensive and simple in structure, and further will improve character and/or image discrimination or may be used for the ornament purpose, and further object to provide an electronic watch using such display apparatus.

According to one aspect of the invention, there is provided a display apparatus which comprises a display member printed in gradations of color from a first color to a second color from one side of the member to other side, an electro-optical display device having plural dot display sections disposed on the display member, each capable of allowing the light to transmit through and preventing the light from transmitting through, and a driving circuit for selectively driving the plural dot display sections of the electro-optical display device to display data such as characters, images, etc. in gradations of color.

The display apparatus of the present invention which is in expensive and simple in structure will display characters and/or images in gradations of color to improve character and/or image discrimination and may be used by way of ornament to other apparatuses.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.FIG. 1is an external plane view of an electronic watch (hereafter, an electronic wrist watch) according to one embodiment of the invention. A round watch casing1has a watch glass2fixed thereon, a liquid crystal display device3under the watch glass2, and a minute hand5and a hour hand6, both rotatably supported by an axis penetrating through the liquid crystal display device3at the center. Further, there is provided a ring shaped hour plate4around the peripheral of the liquid crystal display device3, on which plate hour graduation is printed. On the peripheral surface of the watch casing1, there are provided a light key8, a mode switching key9for switching an operation mode of the electronic watch, and a city selecting key10. The light key8is manipulated to turn on or off an EL (electroluminescence) element7(shown inFIG. 3), which illuminates the liquid crystal display device3from the inside of the device. The city selecting key10is used to chose a city in a world time display mode of the electronic watch.

FIG. 2is a plane view illustrating the liquid crystal display device3in detail. The liquid crystal display device3is provided with a gradation display portion3ain its center part and a data display portion3bat its bottom part, as seen inFIG. 2.

The liquid crystal display device3is formed with a through hole3cat the center, through which hole the axis for supporting the minute and hour hands5,6is inserted. There are disposed plural dot display elements in a 9×8 matrix arrangement on the gradation display portion3aexcluding the center portion (which corresponds to one dot display element) where the through hole3cis formed. The dot display elements disposed at the upper and the bottom portions of the gradation display portion3a(as seen in the drawing) are smallest in shape, and those disposed around the center portion are large in shape. The four dot display elements disposed around the through hole3care of a shape with a part removed.

FIG. 3is an enlarged cross sectional view illustrating the main portion of the electronic wrist watch andFIG. 4is an enlarged cross sectional view showing the main portion of the liquid crystal display device. As shown inFIG. 3, the electronic wrist watch holds a time counting module11in the watch casing1. A bottom cover12is attached to the bottom portion of the watch casing1through a waterproof ring13.

The time counting module11has an analog function and a digital function, and is provided with an upper housing14of synthetic resign and a lower housing15of synthetic resin. The liquid crystal display device3, a multi-color display member16and EL element7are stacked on and received within the upper housing14. An analog movement17is received in the lower housing15. A circuit board18is disposed between the upper housing14and the lower housing15. On the circuit board18is mounted an electronic circuit for driving the liquid crystal display device3. The liquid crystal display device3and the analog movement17are electrically connected to the circuit board18. A hand axis17astudded in an upper surface of the analog movement17penetrates through the through hole3cformed in the liquid crystal display device3appearing from an upper surface of display device3. On an edge portion of the hand axis17aare fixed the minute hand5and the hour hand6.

As shown inFIG. 3andFIG. 4, the liquid crystal display3, the multi color display member16, the EL element7are put together in a stack. The liquid crystal display3is of a negative type, and consists of a pair of transparent electrode substrates21,22, liquid crystal (not shown) enclosed between these electrode substrates21,22and polarizing plates23,24stacked respectively on an upper surface of the electrode substrate21and a bottom surface of the electrode substrate22. When a voltage is selectively applied between the pair of electrode substrates21,22, portions of electrode substrates21,22where the voltage is applied and portions of the polarizing plates23,24where correspond to the portions of the electrode substrates21,22turn to allow the light to transmit through to electro-optically display information such as a time.

In the liquid crystal display device3, when no voltage is applied between the pair of electrode substrates21,22, liquid crystal molecules enclosed between the electrode substrates21,22keep a constant twist orientation so that the light transmitted through the upper polarizing plate23is twisted by the twist orientation of the liquid crystal molecules. The twisted light is blocked by the lower polarizing plate24. Meanwhile, when a voltage is applied between the pair of electrode substrates21,22, liquid crystal molecules enclosed between portions of the electrodes substrates21,22where the voltage is applied to change in the twist orientation so that the light transmitted through the upper polarizing plate23is not twisted by the liquid crystal molecules. The light which is not-twisted is allowed to transmit through the lower polarizing plate24.

The liquid crystal display device3displays information such as a time with the transmitted light and the blocked light. The upper electrode substrate21of the pair of electrode substrates21,22is provided with segment electrodes and the lower electrode substrate22is provided with a common electrode. These segment electrodes and common electrode have connecting wires (not shown) which are guided on a lower surface of the upper electrode substrate21to an edge portion thereof to be electrically connected with a connecting terminal portion.

As shown inFIG. 3, the connecting terminal portion of the upper electrode substrate21is supported by an inter-connector25fixed on the circuit board18and at the same time is electrically connected to the circuit board18through the inter-connector25.

The multi-color display member16is provided on an upper surface of EL element7, facing the lower surface of the liquid crystal display device3, as shown inFIG. 4. The multi-color display member16consists of a white-tinged film26of semi-transmission and reflecting nature, and a multi-ink membrane27of light-transmission nature, which is provided on the film26to covers the whole surface of the film26which faces the liquid crystal device3. Receiving the light, the white-tinged film26allows a part of the received light to transmit as white light and reflects other part of the received light as white light. Ink of light-transmission nature is printed or coated throughout the whole upper surface of the white-tinged film26to form the multi-ink membrane27, as shown inFIG. 4. A portion of the multi-ink member27beneath the gradation display portion3ais colored in blue at a twelve o'clock side, in red at a six o'clock side, and in purple at a center. The colored portion of the multi-ink member27from the twelve o'clock side to the center changes gradually in color from blue to purple, and the colored portion of the multi-ink member27from the center to the six o'clock side changes gradually in color from purple to red. As described, the colored portion of the multi-ink member27beneath the gradation display portion3achanges gradually in color on the twelve o'clock and six o'clock portions and is colored in the same color on the three o'clock and nine o'clock portions. A portion of the multi-color member27beneath the data display portion3bis colored in white.

EL element7consists of light emitting elements of a flat type, and is disposed on the upper housing14, facing the lower surface of the liquid crystal display device3, as shown inFIG. 4. EL element7consists of an upper transparent electrode substrate, a lower electrode substrate, and an electroluminescence layer (EL Layer) disposed between these electrode substrates. When a voltage is applied between the upper and lower electrode substrates, EL layer emits light and illuminates the liquid crystal display device3uniformly from beneath through the upper transparent electrode substrate. The lower electrode substrate is made of a metal or is coated with a reflecting layer to reflect the light emitted from EL layer.

In the electronic wrist watch of the structure set forth above, when a voltage is selectively applied between the pair of electrode substrates21,22of the liquid crystal display device3, the twist orientation of the liquid crystal molecules to which the voltage is applied changes. The portion liquid crystal display device3where the twist orientation of the liquid crystal molecules changes and the portions of the polarizing plates23,24where correspond to the portions of the above liquid crystal display device3turn to allow the light to transmit through. The light incoming through either of the upper and the lower polarizing plates23,24transmits through the pair of electrode substrates21,22and the liquid crystal, and outgoes through the other of the upper and the lower polarizing plates23,24to electro-optically display information such as a time. In the light, since the external light comes in the watch casing1through the watch glass2to illuminate the liquid crystal display device3, a user can read information displayed on the liquid crystal display device3without illumination from EL element7.

When a voltage is applied between the pair of electrode substrates21,22, the external light incoming into the watch casing1transmits through the upper polarizing plate23, the upper transparent electrode substrates21, the liquid crystal display portion where the voltage is applied to allow the light to transmit, the lower transparent electrode substrates22, and the lower polarizing plates24to be radiated onto the multi-color display member16. While the external light radiated onto the multi-color display member16passes through the multi-ink portion27, certain wave length components of the external light are selected depending on the colors of the multi-ink portion27to color the external light. A part of the colored light is reflected toward the liquid crystal display device3and meanwhile the other part of the colored light passes through the multi-color ink portion27and reflected on the white-tinged film26. The reflected light passes through the multi-ink portion27again toward the liquid crystal display device3. The colored light passes through the liquid crystal display device3from beneath to the upper surface of the device3, and therefore information displayed on the device3can be seen in gradations of color through the watch glass2.

FIG. 5is a block diagram showing a circuit configuration of a control system included in the electronic wrist watch shown inFIG. 1. The control system comprises the following elements, that is, a controller41including CPU for controlling whole operation of the electronic wrist watch, including a display operation; ROM42for storing programs and data executed or used by CPU; RAM43for storing data necessary for operation of CPU; a pattern ROM44for storing display and character pattern data; a key input unit45having plural keys to be manipulated for entering various data; a liquid crystal display device46for displaying characters and drawings; a display driver47for driving the liquid crystal display device46; an alarm unit48for generating alarms, using, for instance, a beep sound; an oscillator49for generating a signal of a certain frequency; a divider/timing circuit50for dividing the signal generated by the oscillator to generate and supply signals of 1 Hz, 4 Hz and 8 Hz to control the controller41; and an analog unit51for driving the minute hand5and the hour hand6.

Now, operation of the electronic wrist watch according to the embodiment of the invention with reference to the flow chart ofFIG. 6. In the electronic wrist watch in a standby state, the controller41judges at step S1whether or not the signal of 1 Hz has been entered from the divider/timing circuit50.

When it is determined at step S1that the signal of 1 Hz has been entered, the controller41advances to step S2, where “1 sec.” is added to time information stored on RAM43to update current time information, and a driving signal is supplied to the analog unit51every 20 second to drive the minute hand5by one step. The minute hand5is driven every 20 seconds by one step, and the hour hand6connected with the minute hand5through a series of gears rotates in association with rotation of the minute hand5.

At step S3, processes in a basic time counting and displaying mode, an alarm displaying mode, an address displaying mode and a world time displaying mode are performed, and the controller41returns to step S1.

When it is determined at step S1that the signal of 1 Hz has not been entered, the controller41advances to step S4, where it is judged whether or not the key input unit45is manipulated or any key input is entered. When the key input unit45is not manipulated or no key input is entered, the controller41returns to step S1. When the key input unit45is manipulated or a key input is entered, the controller41performs a key process corresponding to the key input, and then returns to step S1.

FIG. 7is a flow chart representing a detailed procedure of the key process at step S5ofFIG. 6. The controller41judges at step S11whether or not the mode switching key9has been manipulated. When the mode switching key9has been manipulated, the controller41advances to step S12to perform a mode switching process. When the mode switching key9is not manipulated, the controller41advances to step S27ofFIG. 8.

In the mode switching process, the controller41judges at step S13whether a basic time counting and displaying mode has been set or not. When the basic time counting and displaying mode has been set, the controller41advances to step S14to perform a day of the week displaying process. Thereafter, the controller41returns to step S1ofFIG. 6again.

When it is determined at step S13that the basic time counting and displaying mode has not been set, the controller41advances to step S15to judge whether a world time displaying mode has been set or not. When the world time displaying mode has been set, the controller41advances to step S16to display a moving image of the world map on the gradation display portion3afor a predetermined time duration and at the same time to display a city name selected by manipulation of the city selecting key10on the data display portion46for a predetermined time duration.

FIG. 9is a view illustrating a sample of the moving image of the world map. Images of the world map0through9are successively displayed in synchronization with a signal of 8 Hz, such that the world map can be seen as if it rotates. Display patterns of the world map are supplied to the display driver52from the pattern ROM44, and are successively displayed on the gradation display portion3aof the liquid crystal display device3.

After the predetermined time duration has lapsed, the controller41advances to step S18to display a time difference between Greenwich and the city selected and displayed on the gradation display portion3a. Thereafter, the controller41goes to step S19to display a time at the city selected and displayed on the gradation display portion3a. Then, the controller41returns to step S1ofFIG. 6.

When it is determined at step S15that the world time displaying mode has been set, the controller41advances to step S20to judge whether an alarm display mode has been set or not. When the alarm display mode has been set, the controller41advances to step S21, where four images of a bell shown inFIG. 4. are successively displayed on the gradation display portion3aof the liquid crystal display device3in synchronization with a signal of 4 Hz, such that the bell can be seen as if it swings. At step S22, an alarm time is read out from RAM43and displayed on the data display portion3bof the liquid crystal display device3. Thereafter, the controller41returns to step S1ofFIG. 6.

When it is determined at step S20that the alarm display mode has not been set, the controller41advances to step S23to judge whether an address display mode has been set. When the address display mode has been set, the controller41advances to step S24to display an image of a telephone set on the display device3. At step S25the controller41displays a name, an address, a phone number stored on RAM43on the display device46and then returns to step S1ofFIG. 6. When it is determined at step S23that the address display mode has not been set, the controller41goes to step S26to perform other process. Thereafter, the controller41returns to step S1ofFIG. 6.

FIG. 8is a flow chart showing a time-difference display process in the world time display mode. When it is determined at step S11ofFIG. 7that the mode switching key9is not manipulated, the controller advances to step S27ofFIG. 8to judge whether the city selecting key10has been manipulated or not. When the city selecting key10has not been manipulated, the controller judges whether other selecting key is manipulated. When the city selecting key10has been manipulated, the controller advances to step S28.

At step S28, the controller41judges whether the world time display mode has been set or not. When the world time display mode has not been set, the controller41performs other key process. When the world time display mode has been set, the controller41advances to step S29to change city data. At step S30, the controller41displays a name of a city changed at step S29on the data displaying portion3b. At step S31, the controller41determines a current time at the changed city and calculates a time difference between Greenwich time and the current time.

When it is determined that the current time at the city whose name is displayed at step S30falls within a range between 9 o'clock and 16 o'clock (daytime), a time difference (+5) is displayed on the gradation display portion3a(lines4-8) at step S32as shown inFIG. 11A. When it is determined that the current time at the city falls within a range between 16 o'clock and 20 o'clock (evening), a time difference (+5) is displayed on the gradation display portion3a(lines2-6) at step S33as shown inFIG. 11B. When it is determined that the current time at the city falls within a range between 20 o'clock and 4 o'clock (night), a time difference (+5) is displayed on the gradation display portion3a(lines1-5) at step S34as shown inFIG. 11C. When it is determined that the current time at the city falls within a range between 4 o'clock and 9 o'clock (morning), a time difference (+5) is displayed on the gradation display portion3a(lines3-7) at step S34as shown inFIG. 11D. Thereafter the controller41advances to step S36to change city data, and returns to step S1ofFIG. 6.

The time differences will be described, which are displayed on the display device3as shown inFIGS. 11A through 11D. InFIG. 11A, the time difference is displayed on the lowest part of the gradation display portion3a(as seen in the drawing), and a numeral contained in time difference data is displayed in gradations of color from red to purple and a symbol of “+” contained in the time difference data is displayed in gradations of color of red. InFIG. 11B, the time difference is displayed on the upper part of the gradation display portion3a(as seen in the drawing), and the numeral contained in the time difference data is displayed in gradations of color from purple to blue and the symbol of “+” contained in the time difference data is displayed in gradations of color of purple with a tinge of blue. InFIG. 11C, the time difference is displayed on the highest part of the gradation display portion3a(as seen in the drawing), and the numeral contained in time difference data is displayed in gradations of color from blue to purple and the symbol of “+” contained in the time difference data is displayed in gradations of color of blue. InFIG. 11D, the time difference is displayed on the lower part of the gradation display portion3a(as seen in the drawing), and the numeral contained in time difference data is displayed in gradations of color from purple to red and the symbol of “+” contained in the time difference data is displayed in gradations of color of purple with a tinge of red.

In the electronic wrist watch according to the embodiment of the invention, the display device3occupies most of a display area30of the wrist watch and therefore indications such as the world map, the image of a bell, and the alarm time displayed on the display device30can be seen from away. In particular, it can be instantly confirmed from the position and the color in which the data are displayed, whether or not the time differences displayed in the world time display mode is for the city that the user has in mind or whether it is the daytime or nighttime. The display system according to the embodiment allows to improve image discrimination of the display device and a design of the wrist watch. Further, the display device3can be manufactured at a reasonable low cost compared with a conventional color liquid crystal display device. An electronic wrist watch which has advantages set forth above may be produced without requiring an unreasonable high cost.

Further modification and variation can be made to the disclosed embodiments without departing from the subject and spirit of the invention as defined in the following claims. Such modification and variations, as included within the scope of these claims, are meant to be considered part of the invention as described. For example, in the embodiment set forth above the color in which the time differences are displayed varies depending on the current time, but the display device may be modified such that a picture or an animation on which the time differences are displayed in an over lapping manner varies depending on the current time. The display device of the invention may be applied to an electronic apparatus other than the electronic watch to display characters, images, etc. in gradations of color at a low cost, and further to improve its image discrimination and a design of the apparatus.