JP2000214434A - Lcd backlight display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an LCD display from being hard to see even if the LCD is deteriorated due to the use, and further, to improve the LCD display to be easy to see. SOLUTION: The LCD backlight display device comprises plural LED backlight 2a, 2b, 2c, 2d, 2e, 2f, and an LED lighting switching device 3 as backlight for illuminating an LCD panel 1. The LED lighting switching device 3 controls the backlight as plural groups, and changes over backlight being lighted when the backlight is deteriorated and decreased in brightness. For example, in the initial state, the backlight 2a, 2b are lighted for the use, and the backlight 2a, 2b are changed over to the following group of the backlight 2c, 2d when the backlight 2a, 2b are getting decreased in the brightness. Similarly, the backlight 2e, 2f become the following lighting group. By this composition, it is possible to deal with the decrease in brightness due to deterioration of the backlight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an LCD backlight display device, and more particularly, to an LCD backlight display device employing an LED backlight and having an LCD display function.

[0002]

2. Description of the Related Art Conventionally, in an LCD backlight display device including an LCD panel and an LED as a backlight for illuminating the LCD panel, the problem of a decrease in luminous efficiency due to the degradation of the LED cannot be solved. Even if it becomes difficult to see, the user has no choice but to extend the life of the device.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and prevents the display of the LCD from being difficult to see even if deterioration due to the use of the LED occurs.
It is another object of the present invention to improve the display on the LCD so that it is easy to see.

[0004]

According to the first aspect of the present invention, there are provided a plurality of sets of LEDs functioning as a backlight light source, and a plurality of sets of the LEDs.
LED lighting switching means for switching the lighting of D for each group.

According to a second aspect of the present invention, in the first aspect, a light receiving element for measuring the brightness of the LED, an A / D conversion circuit for A / D converting output data from the light receiving element, A CPU for inputting output data from the A / D conversion circuit, wherein the CPU determines the decrease in the brightness of the LED based on the output data from the A / D conversion circuit. The LED is turned on by the lighting switching means.
The control for switching the lighting of is performed.

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided a timer for measuring the integrated lighting time of the LED, and a preset timer for determining the integrated lighting time measured by the timer and the switching of the LED. A memory for storing the switching time to be changed as data, and a CPU;
U is characterized in that when it is determined that the integrated lighting time has reached the switching time, the LED lighting switching means performs control to switch the lighting of the LED.

According to a fourth aspect of the present invention, there are provided a plurality of sets of LEDs functioning as a backlight light source, a light receiving element for measuring the brightness of the LED, and an output data from the light receiving element.
An A / D conversion circuit for performing A / D conversion, a CPU for inputting output data from the A / D conversion circuit, and lighting signal pulse modulation control means for modulating a pulse of a lighting signal of the LED; When the decrease in the brightness of the LED is determined based on output data from the A / D conversion circuit, the lighting signal pulse modulation control means changes the lighting duty of the LED to adjust the brightness of the LED. Is performed.

According to a fifth aspect of the present invention, a plurality of sets of LEDs functioning as a backlight light source, a timer for measuring the integrated lighting time of the LEDs, the integrated lighting time measured by the timer, and the switching of the LEDs are determined. A memory that stores a preset switching time as data for performing
A CPU; and a lighting signal pulse modulating means for modulating a pulse of the lighting signal of the LED, wherein the CPU determines that the accumulated lighting time has reached the switching time, and determines whether the lighting duty of the LED is high. And changing the L
It is characterized in that control for adjusting the brightness of the ED is performed.

According to a sixth aspect of the present invention, in the first aspect, a light receiving element for measuring the brightness of the LED, an A / D conversion circuit for A / D converting output data from the light receiving element, A CPU for inputting output data from the A / D conversion circuit; and a lighting signal pulse modulation control unit for modulating a lighting signal pulse of the LED, wherein the CPU outputs the output data from the A / D conversion circuit. Based on the LED
When it is determined that the brightness of the LED has decreased, either the LED lighting switching means or the lighting signal pulse modulation control means is operated, and switching of the lighting of the LED by the lighting signal or the lighting signal pulse modulation control means is performed. L
It is characterized in that control is performed to change the lighting duty of the ED.

The invention according to claim 7 is the invention according to claim 1, wherein a timer for measuring the integrated lighting time of the LED, and a preset timer for determining the integrated lighting time measured by the timer and the switching of the LED. A memory for storing the switching time to be performed as data, a CPU, and a lighting signal pulse modulation control unit for modulating the lighting signal pulse of the LED, wherein the CPU has reached the switching time when the integrated lighting time has reached the switching time. When it is determined that either of the LED lighting switching means or the lighting signal pulse modulation control means functions, the lighting of the LED is switched by the lighting signal or the LED is turned on by the lighting signal pulse modulation control means. It is characterized in that control is performed so as to change the duty.

[0011] The invention according to claim 8 provides a plurality of sets of LEDs functioning as a backlight light source, LED lighting switching means for switching the lighting of the LEDs for each set, and / or the LEDs.
Lighting signal pulse modulation control means for changing the lighting duty of the LED and adjusting the brightness of the LED; and LC for adjusting the LCD contrast by linking to the change in the brightness of the LED.
And a D contrast adjusting circuit.

According to a ninth aspect of the present invention, in the sixth or seventh aspect of the present invention, L is linked to a change in luminance of the LED.
And an LCD contrast adjusting circuit for adjusting the CD contrast.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the LCD backlight device according to the present invention will be described in detail with reference to the accompanying drawings. In all the drawings for explaining the embodiments, parts having similar functions are denoted by the same reference numerals,
The description of the repetition is omitted.

(Embodiment Corresponding to Claim 1) FIG. 1 is a block diagram for explaining an embodiment of an LCD backlight device according to the present invention. In FIG.
Reference numerals a, 2b, 2c, 2d, 2e, and 2f denote backlights for illuminating the LCD panel 1, and 3 denotes an LED lighting switching device. Here, an LED is assumed as the backlight, but if the light source has a long life, the configuration of the present invention can cope with a decrease in luminous efficiency due to deterioration. In the LCD backlight device of the present embodiment, first, the first set of backlights 2a and 2b are turned on and used, then the second set of backlights 2c and 2d are turned on, and then the third set of backlights is used. Lights 2e and 2f are used.

(Embodiment Corresponding to Claim 2) FIG. 2 is a block diagram for explaining another embodiment of the LCD backlight device according to the present invention. In FIG.
The / D conversion circuit 6 is a CPU. The light receiving element 4 functions as a sensor that detects deterioration of the light source (backlight). The output of the light receiving element 4 is converted into a digital signal by an A / D conversion circuit 5, which is determined by a CPU 6.
The ED lighting switching device 3 is controlled. LED lighting switching device 3
Switches the lighting of the backlights 2a to 2f for each set.

(Embodiment Corresponding to Claim 3) FIG. 3 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention, in which 7 is a timer and 8 is a memory. is there. Switching time data is stored in the memory 8 as backlight deterioration prediction data in advance, and the lighting time is measured by a timer (hardware / software) 7 and the CPU 6 determines the life based on these data, The LED lighting switching device 3 is controlled.

(Embodiment Corresponding to Claim 4) FIG. 4 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In FIG. An LED / PWM control device that functions as a means. The output of the light receiving element 4 is converted into a digital signal by the A / D conversion circuit 5, which is determined by the CPU 6 and controlled by the LED / PWM control device 9. For example, 1/4
When deterioration of the LED that has been lit at duty is detected, the LED is lit at １ ／ duty, and thereafter, ｄd
By performing control to gradually increase the luminance, such as turning on the light in the uty, it is possible to maintain a state that is easy for the user to see.

(Embodiment Corresponding to Claim 5) FIG. 5 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. Backlight L
An embodiment according to claim 4, wherein the CPU determines the life of the backlight based on the data of the memory and the timer (regardless of hardware / software) storing degradation prediction data (switching time data) of the ED. Similarly, the LED / PWM control device 9 controls the LED brightness.

(Embodiment Corresponding to Claim 6) FIG. 6 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In the present embodiment, both functions of the embodiment corresponding to claim 2 and the embodiment corresponding to claim 4 are effectively executed. For example, if the brightness of the LED decreases, the duty of the PWM is increased, and if that is not sufficient, control is performed to switch the LED to be turned on.

(Embodiment Corresponding to Claim 7) FIG. 7 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In this embodiment, the judgment of the life data of the embodiment according to claim 6 is performed by comparing the data of the memory 8 and the timer (hardware / software) 7 in which the deterioration prediction data (switching time data) of the backlight LED is stored in advance. Is performed by the CPU 6 based on the

(Embodiment Corresponding to Claim 8) FIG. 8 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In FIG. Is LE in the above-described embodiment.
This is an LED brightness adjustment device having the functions of the D lighting switching device 3 and the LED / PWM control device 9. This embodiment uses an LCD
LCD contrast adjustment circuit 1 for adjusting contrast
0 is provided. Since the visibility of the LCD is related to the brightness of the LCD backlight, when the brightness of the backlight decreases, the LCD contrast is adjusted to an appropriate and easily viewable. In FIG. 8, the CPU 6 is drawn by a dotted line,
This indicates that the control may be performed automatically by software including a CPU or a manual may be used. Further, it may be constituted only by pure hardware without the CPU 6 interposed.

(Embodiment Corresponding to Claim 9) FIG. 9 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In this embodiment, the life data in the embodiment corresponding to claim 8 is obtained by the light receiving element 4 and the A / D conversion circuit 5.

FIG. 10 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention. In this embodiment, the life data in the embodiment according to claim 8 is obtained by the timer 7 and the memory 8.

[0024]

According to the first aspect of the present invention, since a plurality of sets of LEDs are provided with LED lighting switching means for switching the lighting LEDs for each group, a new backlight can be used even if the brightness is reduced due to the life of the backlight. By switching the display to the LCD display, the brightness that is easy for the user to see can be maintained.

According to the second aspect of the present invention, since a light receiving element for judging switching of the lighting LED by the LED lighting switching means is provided, the switching can be performed according to the actual brightness of the backlight. More realistic brightness can be handled for the user.

According to a third aspect of the present invention, a timer and a memory are provided, and the switching of the lighting LED by the LED lighting switching means is determined by estimating the life of the backlight. can do.

According to the fourth aspect of the present invention, since the lighting signal pulse modulation control means for modulating the pulse of the lighting signal of the LED is provided, even if the luminance is reduced due to the life of the LED, the PWM duty is increased. The use of LEDs can continue to be used, which is more economical. In addition, D of the lighting LED by the lighting signal pulse modulation control means is controlled.
Since a light receiving element for judging a change in uty is provided, adjustment can be performed in accordance with the actual brightness of the backlight, and more realistic brightness can be handled for the user.

According to the fifth aspect of the present invention, since the lighting signal pulse modulation control means for modulating the pulse of the lighting signal of the LED is provided, even if the brightness is reduced due to the life of the LED, the PWM duty is increased. The use of LEDs can continue to be used, which is more economical. In addition, since a timer and a memory are provided and the change in the duty of the lighting LED is determined by the lighting signal pulse modulation control means by estimating the life of the backlight, the brightness that is easy for the user to see can be maintained by a simple mechanism. .

Since the invention according to claim 6 includes the lighting signal pulse modulation control means and the LED lighting switching means, the backlight can be economically and effectively switched by incorporating the functions of both means. be able to. Also,
Switching of lighting LED by backlight switching means and duty of lighting LED by lighting signal pulse modulation control means
Because it has a light receiving element to determine the change of
Switching and adjustment can be performed according to the actual brightness of the backlight, and more realistic brightness can be handled for the user.

Since the invention of claim 7 includes the lighting signal pulse modulation control means and the LED lighting switching means, it is possible to economically and effectively switch and adjust the backlight by incorporating the functions of both means. It can be performed. In addition, it has a timer and a memory, estimates the life of the backlight, switches the lighting LED by the LED lighting switching means, and turns on the lighting LED by the lighting signal pulse modulation control means.
, The brightness that is easy for the user to see can be maintained by a simple mechanism.

Since the invention of claim 8 includes the lighting signal pulse modulation control means and / or the LED lighting switching means, economical and effective backlight switching and adjustment can be performed. In addition, since the LCD has a LCD contrast adjustment circuit, L
The contrast of the CD can be adjusted, and a display that is easier for the user to see can be obtained.

The ninth aspect of the present invention includes the LCD contrast adjustment circuit, so that the contrast of the LCD can be adjusted according to the brightness of the backlight, and a display that is more visible to the user can be obtained. Also,
Since the lighting signal pulse modulation control means and the LED lighting switching means are provided, it is possible to economically and effectively switch and adjust the backlight by incorporating the functions of both means. In addition, since there is provided a light receiving element or a timer and a memory for judging a change of the duty of the lighting LED by the switching of the lighting LED by the LED lighting switching means and the lighting signal pulse modulation control means,
Switching and adjustment can be performed according to the actual brightness of the backlight, and more realistic brightness can be handled for the user.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of an LCD backlight device according to the present invention.

FIG. 2 is a block diagram for explaining another embodiment of the LCD backlight device according to the present invention.

FIG. 3 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 4 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 5 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 6 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 7 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 8 is a block diagram for explaining still another embodiment of the LCD backlight device according to the present invention.

FIG. 9 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

FIG. 10 is a block diagram illustrating still another embodiment of an LCD backlight device according to the present invention.

[Explanation of symbols]

1: LCD panel, 2a, 2b, 2c, 2d, 2e, 2
f: backlight, 3: LED lighting switching device, 4: light receiving element, 5: A / D conversion circuit, 6: CPU, 7: timer,
8 memory, 9 LED / PWM control device, 10 LC
D contrast adjustment circuit, 11 ... LED brightness adjustment device.

Claims (9)

[Claims] A plurality of sets of LEDs functioning as a backlight light source, and an LED for switching the lighting of the LEDs for each set
An LCD backlight display device comprising lighting switching means. 2. The LCD backlight display device according to claim 1, wherein: a light receiving element for measuring luminance of the LED; an A / D conversion circuit for A / D converting output data from the light receiving element; A CPU for inputting output data from the A / D conversion circuit, wherein the CPU determines the decrease in the brightness of the LED based on the output data from the A / D conversion circuit. An LCD backlight display device, wherein a control for switching the lighting of the LED is performed by lighting switching means. 3. The LCD backlight display device according to claim 1, wherein a timer for measuring an integrated lighting time of the LED, and a preset timer for determining the integrated lighting time measured by the timer and switching of the LED. A memory for storing the switching time to be performed as data, and a CPU. When the CPU determines that the integrated lighting time has reached the switching time, the CPU turns on the LED by the LED lighting switching means. An LCD backlight display device for performing control for switching between the two. 4. A plurality of sets of LEDs functioning as a backlight light source, a light receiving element for measuring luminance of the LED, and an A / D converter for A / D converting output data from the light receiving element.
A CPU for inputting output data from the A / D conversion circuit; a lighting signal pulse modulation control unit for modulating a pulse of a lighting signal of the LED;
When the decrease in the brightness of the LED is determined based on output data from the A / D conversion circuit, the lighting signal pulse modulation control means changes the lighting duty of the LED to adjust the brightness of the LED. LCD backlight display device for performing control to perform the following. 5. A plurality of sets of LEDs functioning as a backlight light source, a timer for measuring an integrated lighting time of the LEDs, an integrated lighting time measured by the timer, and the L
A memory for storing, as data, a switching time set in advance to determine the switching of the ED; a CPU;
Lighting signal pulse modulating means for modulating the pulse of the lighting signal of the ED, wherein the CPU determines that the integrated lighting time has reached the switching time;
An LCD backlight display device, wherein control for changing the lighting duty of D and adjusting the brightness of the LED is performed. 6. The LCD backlight display device according to claim 1, wherein: a light receiving element for measuring luminance of the LED; an A / D conversion circuit for A / D converting output data from the light receiving element; A CPU for inputting output data from the A / D conversion circuit; and lighting signal pulse modulation control means for modulating a lighting signal pulse of the LED;
U determines whether or not the brightness of the LED has decreased based on output data from the A / D conversion circuit.
Either the lighting switching means or the lighting signal pulse modulation control means is operated, and control is performed such that the lighting of the LED is switched by the lighting signal or the lighting duty of the LED is changed by the lighting signal pulse modulation control means. An LCD backlight display device characterized by the above-mentioned. 7. The LCD backlight display device according to claim 1, wherein a timer for measuring an integrated lighting time of the LED, and a preset timer for determining the integrated lighting time measured by the timer and switching of the LED. A memory for storing the switching time to be performed as data, a CPU, and lighting signal pulse modulation control means for modulating the lighting signal pulse of the LED, wherein the CPU has reached the switching time when the integrated lighting time has reached the switching time. When it is determined that either of the LED lighting switching means or the lighting signal pulse modulation control means functions, the lighting of the LED is switched by the lighting signal or the LED is turned on by the lighting signal pulse modulation control means. An LCD backlight display device which controls to change the duty. 8. A plurality of sets of LEDs functioning as a backlight light source, and LEDs for switching lighting of the LEDs for each set
A lighting switching means and / or a lighting signal pulse modulation control means for changing the lighting duty of the LED to adjust the brightness of the LED; and an LCD contrast adjusting circuit for adjusting the LCD contrast by linking to the change in the brightness of the LED. An LCD backlight display device comprising: 9. The LCD backlight display device according to claim 6, further comprising: an LCD contrast adjustment circuit that adjusts an LCD contrast by linking to a change in luminance of the LED. apparatus.