JP2001083481A - Electronics - Google Patents

Abstract

(57) [Summary] An object of the present invention is to reduce the current consumption of a backlight by using the backlight at a place where the luminous efficiency is highest. SOLUTION: An external switch for backlight 901 is set to o.
When the state becomes the n state, the CPU 903 recognizes the on state, reads the display data for transmission from the RAM 905, outputs the display data for transmission to the driver IC 906, and performs the display for transmission on the display element. Turn on the backlight element at the same time

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a liquid crystal panel, such as a table clock, a wristwatch, a stopwatch and the like.

[0002]

2. Description of the Related Art Conventionally, electronic devices that display numbers, characters, and other information using a flat display device such as a liquid crystal display device have been widely known. For example, now, considering an electronic device using a liquid crystal display device,
For example, as shown in FIG. 9, the electronic device includes a liquid crystal panel 21 in which a liquid crystal 204 is sandwiched between an upper glass 202 and a lower glass 205 in which a color filter 203 is formed on a side of the upper glass 202 on the viewer side in contact with the liquid crystal 204. A pair of polarizing plates 201 and 206 are arranged on both sides of the body, and further,
It is configured by disposing a transflective plate 207 on the back side of one polarizing plate 206 and a light emitting element 208 on the back side of the transflective plate 207. The pair of polarizing plates 52 and 53 are arranged such that their azimuths are perpendicular to each other.

[0003] In this conventional electronic device, information such as numbers is displayed using external light during bright daytime, and the light-emitting element 208 is illuminated as necessary during darkness at night, and the number is used using the light. Etc. is displayed. The display of information such as numbers is performed by applying a predetermined voltage between the electrodes of the liquid crystal panel 21, and a region where no voltage is applied becomes a white background or a background of an appropriate color. In the figure, a region where information is displayed when a voltage is applied is represented by “ON”, and a background region where no voltage is applied is represented by “OFF”.

When the background is displayed using the external light (the liquid crystal panel 21 is turned off), as shown by an arrow P, the linearly polarized light in the direction parallel to the paper of the external light, that is, the natural light, is polarized. And the color filter 2
03 allows only light in a part of the wavelength region to pass through to become colored light. The polarization direction of this colored light is twisted by 90 ° by the liquid crystal panel 21 in the OFF state, and becomes linearly polarized light in a direction perpendicular to the paper surface. The linearly polarized light is irregularly reflected on the surface of the semi-transmissive reflection plate 207 after passing through the polarizing plate 206, and a part of the irregularly reflected light is transmitted to the polarizing plate 206, the liquid crystal panel 21, and the polarizing plate 201 in order, and then is transmitted to the outside. Is displayed.
By displaying all the red, green, and blue colored lights of the color filter 203, the part is recognized as a white background.

When information such as numbers is displayed by using external light (the liquid crystal panel 21 is turned on), linearly polarized light parallel to the plane of the drawing is extracted from the external light by the polarizing plate 201 as shown by an arrow Q. Color filter 203
As a result, only light in a part of the wavelength range is transmitted and becomes linearly polarized colored light. The linearly polarized light passes through the liquid crystal panel 21.
At this time, since the liquid crystal panel 21 is in the ON state, the polarization direction of the linearly polarized light is maintained in a direction parallel to the plane of the paper without being twisted.
Therefore, the linearly polarized light is absorbed by the polarizing plate 206. As a result, the colored light becomes a colored light that is in the wavelength range of the colored light. For example, the liquid crystal of the red color filter is turned off.
By setting the liquid crystal in the green and blue portions to the on state in the f state, this portion is recognized as red.

On the other hand, when the background is displayed using the light emission of the light emitting element 208 (the liquid crystal panel 21 is turned off), linearly polarized light in the direction perpendicular to the plane of the drawing is extracted by the polarizing plate 206 from the light emission of the light emitting element 208, that is, natural light. ,
The polarization direction of the linearly polarized light is twisted by 90 ° by the liquid crystal panel 21 in the OFF state and is converted into linearly polarized light in a direction parallel to the plane of the paper, and only light in a part of the wavelength region is transmitted by the color filter 203 to be colored light. The linearly polarized light passes through the polarizing plate 52 and is recognized outside. The color of the light recognized at this time is the color of the wavelength transmitted through the color filter 203 among the emission colors of the light emitting element 208, the emission color is white, and the red, green, and blue color filters 203 When the liquid crystal of a part is turned off, it is recognized as white.

When information such as numbers is displayed using the light emission of the light emitting element 208 (the liquid crystal panel 21 is turned on), linearly polarized light in a direction perpendicular to the plane of the drawing is extracted from the light emission of the light emitting element 208 by the polarizing plate 206. Linearly polarized light
The light passes through the liquid crystal panel 21 in the ON state, and is transmitted through the color filter 203 only as light in a part of the wavelength region to become colored light, and reaches the polarizing plate 201. The linearly polarized light at this time does not match the polarization direction of the polarizing plate 52, and is thus absorbed by the polarizing plate 201. As a result, when the liquid crystal of all the red, green, and blue portions of the color filter of the same dot is turned on, it is recognized as "black" from the outside.

[0008]

As is apparent from the above description, in the above-mentioned conventional electronic apparatus, when color display is to be performed, display is performed using light emitting elements unless the light emitting elements are white light. Sometimes color display was not possible.

However, white light using a generally used fluorescent tube has a very high voltage for emitting light and requires a large amount of current to generate a high voltage. It was getting bigger.

Other general light emitting means has a wavelength range in which light is efficiently emitted. In order to emit white light, filtering is performed to make the emission color white, so that the amount of light output is small. Had dropped. For this reason, in the method of illuminating a color panel with white light, in order to compensate for a reduced output in order to obtain a sufficient luminance, a current is consumed to obtain a necessary brightness.

FIG. 1 is a diagram showing an example in which transmissive display is performed with color display data using a light-emitting element other than white light, for example, an EL backlight that emits blue-green light.
An emission spectrum like 0 is obtained. As shown in FIG. 10, the difference between the spectrum when displayed in green and the spectrum when displayed in blue becomes very small, and the spectrum when displayed in red has a maximum luminance of less than 5 cd / m2. I will not be able to. In such a display, not only is it difficult to distinguish between green and blue, but also it is not possible to distinguish between red and black. For this reason, red, blue, or a color combined with these luminescent colors is different from the color to be displayed, and the visibility of the display is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in an electronic apparatus of a type that selects and displays either natural light or a light-emitting element. It is an object of the present invention to reduce current consumption even when a light emitting element is selected without impairing performance.

[0013]

In order to achieve the above object, an electronic apparatus according to the present invention is an electronic apparatus having a liquid crystal panel for display, and includes elements necessary for displaying the liquid crystal panel. A circuit board on which the liquid crystal panel is mounted, connecting means for electrically connecting the liquid crystal panel with the circuit board on which elements necessary for displaying the liquid crystal panel are mounted, and light in a direction of a display surface of the liquid crystal panel for display. A light emitting means for emitting light, a circuit board on which elements necessary for causing the light emitting means to emit light are mounted, and a circuit board on which the light emitting means and elements for causing the light emitting means to emit light are electrically connected. It has a connection means and a circuit board on which elements capable of recognizing that the light emitting means emits light and changing display data of a liquid crystal panel for display are mounted.

When sufficient external light for recognizing the display is obtained, display is performed in the reflection mode. When external light sufficient for recognizing the display is not obtained, display is performed using a backlight. Recognize At this time, the light source used is caused to emit light with the optimum luminous efficiency, and in that case, the display data is displayed according to the emission wavelength of the light source,
Absorption of light at a specific wavelength is eliminated, which is preferable without lowering display visibility. Further, it is preferable that a light source is used to emit light at an optimum efficiency, because current consumption in the backlight can be reduced.

When the liquid crystal panel for display is a liquid crystal panel compatible with color display, light of a specific wavelength is absorbed by performing color display. Changing the display data is preferable in that display can be performed without lowering visibility.

The use of anisotropic conductive rubber as the connection means for electrical connection with the circuit board is preferable in that the space for electrical conduction of the circuit board can be reduced.

By using a heat seal connector as a connection means for electrically connecting a liquid crystal panel to a circuit board on which elements necessary for displaying a liquid crystal panel for display are mounted, anisotropic conductive rubber is used. Is more preferable in that conduction of a liquid crystal panel having a narrower electrode pitch is more secure than when using.

A driver IC necessary for driving the liquid crystal panel is mounted as a connecting means for electrically connecting the liquid crystal panel to a circuit board on which elements necessary for displaying the liquid crystal panel for display are mounted. The use of the flexible substrate described above is more preferable than the case of using an anisotropic conductive rubber in that conduction of a liquid crystal panel having a narrower electrode pitch is easier.

The use of electroluminescence as the light emitting means is preferable in that a thin and uniform surface light emission can be obtained.

The use of a light-emitting color having the highest luminous efficiency as the electroluminescence used for the light source is preferable from the viewpoint that current consumption for illumination can be reduced.

The use of an LED element as the light emitting means is preferable from the viewpoint that current consumption can be reduced.

It is preferable from the viewpoint that uniform surface light emission can be obtained by using light guide means for uniformly emitting light emitted when an LED element is used as the light emitting means.

At least two of red, green and blue light emitting means
It is preferable to use an LED capable of emitting more than two types of light because it is possible to select an emission color according to the user's preference.

At least three of red, green and blue as light emitting means
By using LEDs that can emit more than one kind of light, it is possible to select the emission color according to the user's preference. By turning on red, green and blue simultaneously, it is possible to obtain white light emission, transmission This is preferable in that color display can be performed even during display.

It is said that by mounting the elements necessary for displaying the liquid crystal panel for display and the elements necessary for causing the light emitting means to emit light on the same circuit board, the cost and space required for the board can be reduced. It is preferable from the viewpoint.

It is preferable to attach a belt for carrying to the case of the electronic device from the viewpoint of improving the portability of the electronic device.

It is preferable that the outer case of the electronic device has a waterproof structure since the reliability of the electronic device can be improved.

[0028]

(Embodiment 1) FIG. 1 shows a sectional structure of an electronic device module which is an embodiment of an electronic device according to the present invention. In the present embodiment, as shown in FIG. 1, a panel frame 1, a color liquid crystal panel 2, an EL backlight 31, elements necessary for lighting the color liquid crystal panel 2, and the EL backlight 31 emit light. A circuit board 4 on which elements necessary for the circuit board are mounted, a circuit board frame 5 for holding the circuit board 4, a conductive rubber 6a for electrically connecting the circuit board 4 and the color liquid crystal panel 2, and an EL. A conductive rubber 6b for electrically connecting the backlight 31 to the circuit board 4, a battery 7 for supplying power to the circuit board, screws 8 for fixing the circuit board frame 5 and the panel frame 1, It has. Also, when the switch of the EL backlight 31 recognizes the on state,
EL backlight 3 with display colors registered in advance
Elements necessary for changing the display color to one emission wavelength are mounted.

FIG. 2 is a functional block diagram showing a first embodiment of the electronic apparatus of the present invention.

When the color display panel is viewed in reflection display, the external switch for backlight 901 is in the off state, and the CPU 903 recognizes this. At this time, the CPU 903 reads the display data for reflection from the RAM 905, outputs the display data for reflection to the driver IC 906, and performs reflection display on the display element.

When the color display panel is viewed in transmissive display, the backlight external switch 901 is turned on, and the CPU 903 recognizes the on state. At this time C
The PU 903 reads the display data for transmission from the RAM 905, outputs the display data for transmission to the driver IC 906, performs the display for transmission on the display element, and simultaneously turns on the backlight element.

In this way, for example, monochrome display is performed as a transmissive display by using a color filter having a transmissive characteristic as shown in FIG. 3 and an EL backlight having a blue-green light emitting characteristic as shown in FIG. In this case, an emission spectrum as shown in FIG. 5 is obtained. FIG. 6 shows an emission spectrum when a color display is performed by driving an EL backlight that emits white light at the same current consumption value as the emission spectrum of FIG. Comparing the spectra shown in FIGS. 5 and 6, it can be seen that the difference in luminance obtained is clearly higher in the monochrome display of FIG. 5 even with the same current consumption value.

As described above, the display data at the time of reflection display and the display data at the time of transmission display are adjusted to light. In this embodiment, the display at the time of reflection is color display, and the display at the time of transmission is monochrome display. By doing so, the backlight can be used efficiently without lowering the display quality of each.

Example 2 FIG. 7 shows a cross-sectional structure of an electronic device module which is an embodiment of the electronic device according to the present invention. In the present embodiment, as shown in FIG.
A color liquid crystal panel 2, an LED element 32 that can arbitrarily select three types of light emission of red, green, and blue, and a light guide plate 33 for efficiently emitting light from the LED element 32 into surface light.
A circuit board 4 on which elements necessary for lighting the color liquid crystal panel 2 and elements necessary for causing the LED elements 32 to emit light, a circuit board frame 5 for holding the circuit board 4, and a circuit board A conductive rubber 6a for electrically connecting the color liquid crystal panel 4 to the color liquid crystal panel 2, a battery 7 for supplying power to the circuit board, and screws 8 for fixing the circuit board frame 5 and the panel frame 1 are provided. Have. When the switch of the LED element 32 recognizes the ON state, the circuit board 4 displays the LED element 3 in which the display color is registered in advance.
Elements required for changing the display color to the emission wavelength of No. 2 are mounted.

FIG. 8 is a functional block diagram showing a first embodiment of the electronic apparatus of the present invention.

When the color display panel is viewed in reflection display, the external switch for backlight 901 is in the off state, and the CPU 903 recognizes this. At this time, the CPU 903 reads the display data for reflection from the RAM 905, outputs the display data for reflection to the driver IC 906, and performs reflection display on the display element.

When the color display panel is to be viewed in a transmissive display, the user selects an emission color in advance by using an emission color selection external switch 908.

In this state, the user turns on the external switch 901 for backlight, and the CPU 903 recognizes the on state. At this time, the CPU 903 reads the display data for transmission according to the emission color from the RAM 905, outputs the display data for transmission according to the emission color to the driver IC 906, and performs the display for transmission on the display element and the backlight at the same time. Light the element.

In this manner, the user can select eight emission colors, and when it is necessary to see the color display, the user can select the white emission color to display the transparent display. Sometimes it is possible to see the color display. Therefore, the user can change the emission color of the backlight according to the required display, and when the color display is not necessary, the current consumption of the backlight can be reduced by limiting the emission color. .

Although the light emission color is selected in advance, the light emission color can be changed even after the backlight is turned on. In this case, operating the emission color selection switch in the state of the emission color that has been selected in advance,
Determine the emission color. CPU 90 recognizing the change in emission color
3 reads out the display data for transmission corresponding to the selected luminescent color from the RAM 905, outputs the display data for transmission corresponding to the luminescent color to the driver IC 906, and rewrites the display data with the display element. The backlight element is turned on in the selected lighting color.

As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to those embodiments, and can be variously modified within the scope of the invention described in the claims.

For example, in the above embodiment, the case where the present invention is applied to a wristwatch is illustrated, but the present invention can be applied to other electronic devices such as a stopwatch. In addition, any light emitting device other than EL can be used as the light emitting means.

Although a conductive rubber is used as a method of electrically connecting a liquid crystal panel for color display and a circuit board, a flexible tape substrate or the like may be used instead.

Similarly, conductive rubber is used as a means for conducting the EL backlight and the circuit board.
A connection method using a conductive spring or a lead wire can also be used.

Further, as a means for changing the display data of the color display panel, a method of processing by software has been described, but processing by hardware may be performed.

[0046]

As described above, according to the present invention, when performing transmissive display, the display of the liquid crystal panel is switched according to the characteristics of the backlight to switch the display data, whereby the illumination can be used with the optimum luminous efficiency. Thus, the current consumption can be reduced. Further, by setting the display data according to the emission wavelength, the visibility of the display at the time of transmission is not reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a cross-sectional structure of an embodiment of an electronic device module which is an embodiment of an electronic device according to the invention.

FIG. 2 is a functional block diagram illustrating an embodiment of an electronic apparatus according to the invention.

FIG. 3 is a graph of transmittance characteristics of a color filter showing one embodiment of an electronic device according to the present invention.

FIG. 4 is a diagram illustrating an electronic apparatus according to an embodiment of the present invention;
It is a graph of the emission spectrum of L backlight.

FIG. 5 is a graph of an emission spectrum when an EL backlight that emits blue green light according to an embodiment of the electronic apparatus of the present invention is displayed in black and white through transmission using the color filter of FIG. 3;

6 is a graph of an emission spectrum when the color of the EL backlight that emits white light is displayed in color by transmission using the color filter of FIG. 3, showing an embodiment of the electronic apparatus according to the present invention.

FIG. 7 is a cross-sectional view illustrating a cross-sectional structure of an embodiment of an electronic device module which is an embodiment of the electronic device according to the invention.

FIG. 8 is a functional block diagram illustrating an embodiment of an electronic apparatus according to the invention.

FIG. 9 is a diagram schematically illustrating a main part of an embodiment of an electronic apparatus according to the invention.

FIG. 10 shows an EL backlight that emits blue-green light according to an embodiment of the electronic apparatus of the present invention.
6 is a graph of an emission spectrum when color display is performed by transmission using the color filter of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Panel frame 2 Color liquid crystal panel 21 Liquid crystal panel 201 Polarizer 202 Upper glass 203 Color filter 204 Liquid crystal 205 Lower glass 206 Polarizer 207 Transflective reflector 208 Light emitting element 31 EL backlight 32 LED element 33 Light guide plate 4 Circuit board 5 Circuit Board frame 6a, b Conductive rubber 7 Battery 8 Screw 901 External switch for backlight 902 Backlight element 903 CPU 904 ROM 905 RAM 906 Driver IC 907 Display element 908 External switch for display color selection

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 348 G09F 9/00 348M 5G435 348N 9/30 390 9/30 390C H01L 33/00 H01L 33 / 00 FF term (reference) 2H089 HA40 JA10 QA07 QA16 TA03 TA07 TA18 TA20 2H092 GA47 GA49 GA50 NA22 NA26 PA06 PA13 2H093 NA61 NC14 NC21 NC42 NC43 NC50 ND14 ND17 ND39 NE06 NE10 5C094 AA08 AA10 BA23A48A48A48A48A48A48 DB02 EB02 ED03 ED11 ED14 ED20 FA01 FA02 GA10 HA10 5F041 AA12 AA24 DC91 EE25 FF11 5G435 AA03 AA04 AA18 BB12 BB15 BB16 CC12 DD11 EE26 EE40 EE42 EE45 EE47 FF05 FF08 GG11 GG12GG23

Claims (14)

[Claims] 1. An electronic device having a liquid crystal panel for display, comprising: a circuit board on which elements necessary for displaying the liquid crystal panel are mounted; and an element necessary for displaying the liquid crystal panel. Mounting means for electrically connecting the circuit board and the liquid crystal panel, light emitting means for emitting light in the direction of the viewer of the display liquid crystal panel, and elements necessary for causing the light emitting means to emit light are mounted. A connection means for electrically connecting the circuit board with a circuit board on which the light emitting means and the elements for causing the light emitting means to emit light; and a display of a liquid crystal panel for displaying by recognizing that the light emitting means emits light. An electronic device, comprising: a circuit board on which elements capable of changing data to display data different from a state when the light emitting unit emits light are mounted. 2. The electronic device according to claim 1, wherein the display liquid crystal panel is a panel capable of performing color display. 3. The electronic device according to claim 1, wherein anisotropic conductive rubber is used as connection means for electrical connection with the circuit board. 4. The electronic device according to claim 1, wherein a heat seal connector is used as connection means for electrical connection with a circuit board. Electronics. 5. The electronic device according to claim 1, wherein a circuit board on which elements necessary for displaying a liquid crystal panel for display are mounted, and a liquid crystal panel are electrically connected. As connection means for connecting to
An electronic device using a flexible substrate on which a driver IC necessary for driving a liquid crystal panel is mounted. 6. The electronic device according to claim 1, wherein electroluminescence is used as said light emitting means. 7. The electronic device according to claim 6, wherein a luminescent color having the highest luminous efficiency of electroluminescence is used. 8. The electronic device according to claim 1, wherein an LED element is used as said light emitting means. 9. The electronic device according to claim 8, wherein
An electronic apparatus, comprising: a light guide unit for uniformly emitting light emitted by a D element. 10. The electronic device according to claim 9, wherein at least two or more types of LEs that can be selected by an observer.
An electronic device using a D element. 11. The electronic device according to claim 10, wherein
An electronic device using LED elements of at least three kinds of emission colors of red, green, and blue. 12. The electronic device according to claim 1, wherein elements necessary for displaying a liquid crystal panel for color display and light emitting means required for light emission are provided. An electronic device, wherein elements are mounted on the same circuit board. 13. The electronic device according to claim 1, wherein a belt for carrying the electronic device is attached to a case of the electronic device. 14. The electronic device according to claim 1, wherein an outer case of the electronic device has a waterproof structure.