JP3914312B2 - Illumination light control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illumination light control device, and more particularly to an illumination light control device that adjusts the amount of illumination light.
[0002]
[Prior art]
For example, a car air conditioner or the like is provided with a display panel that informs the user of the operating state of the car air conditioner or setting conditions. Many display panels are configured to light up the fluorescent display tubes and light emitting diodes (LEDs) so that the display contents can be seen more easily. The brightness of the fluorescent display tubes and LEDs is usually set by the user. It is adjusted by rotating a dial type switch according to the desired light quantity.
[0003]
A signal representing brightness set by the user is input to a microcomputer that performs frequency voltage conversion (FV conversion) and executes dimming control (illumination control).
[0004]
FIG. 5 is a diagram showing the relationship between the brightness of the illumination light and the rotation amount of the dial switch. In the figure, the rotation amount of the dial type switch is expressed in percentage, 100% indicates the maximum rotation amount of the dial type switch, and 0% indicates the radiation light emission stop. Further, in the figure, the memory capacity for determining the rotation amount of the dial type switch on the microcomputer is shown by the number of bits.
[0005]
According to FIG. 5, the dial type switch is clicked when rotated to 98% and is set to a rotation amount of 100%, and is clicked when the rotation amount is decreased to 2% to stop the emission of illumination light.
[0006]
In addition, the dial switch on the microcomputer has a rotation amount determination with a hysteresis of about 1 bit. When the light quantity is gradually increased, the illumination light is input when 5 to 8 bits are input to the memory. The maximum amount of light is emitted with 252 bits. When the amount of light is gradually reduced, the emission of the maximum amount of light is finished from 248 bits to 251 bits, and the emission of illumination light is stopped at 4 bits.
[0007]
[Problems to be solved by the invention]
However, the illumination control described above has a relatively small hysteresis of about 1 bit. For this reason, the brightness of the illumination light may become unstable when setting the maximum light quantity and radiation stop.
[0008]
Further, since the FV conversion circuit has a time constant, it takes a relatively long time to respond to illumination control. For this reason, it may take time until the illumination light is emitted from the user's operation, or the timing may be shifted between the click of the dial switch and the emission of the maximum light amount.
[0009]
The present invention has been made in view of the above points, and in particular, provides an illumination light control device that stabilizes the radiation of the maximum amount of illumination light and the brightness when radiation is stopped, and has less operational discomfort. It is intended to do.
[0010]
[Means for Solving the Problems]
The problems described above are solved by the following means.
[0011]
An illumination light control device that controls the amount of illumination light, has a pulse width according to the set amount of light, and does not output a rectangular wave when the illumination light stops or emits the maximum amount of light, and is a constant DC voltage. A light amount setting means (1) for generating a PWM signal, a light amount signal generating means (3) for generating an integrated signal (4) obtained by integrating the PWM signal output from the light amount setting means (1 ), and the light amount a differential signal generating means for generating a setting means (1) differential signal obtained by differentiating the PWM signal outputted from the (6) (5), the light amount signal generating means (3) output from the said product component signal (4 ) while adjusting the amount of illumination light in accordance with the voltage value of the differential signal (6) is the due to the PWM signal is a constant DC voltage when the illumination light stop or maximum light emission Derived from differential signal generation means (5) When not, characterized by having a said integral signal (4) light control means for determining a stop or maximum light emission of the illumination light in accordance with the voltage value of (7).
[0012]
By configuring in this way, the light quantity of the illumination light is adjusted according to the voltage value of the integrated signal output from the light quantity signal generating means, while the PWM signal is a constant DC voltage when the illumination light is stopped or the maximum light quantity is emitted. Therefore, when the differential signal is not output from the differential signal generating means, the stop of the illumination light or the maximum light amount emission can be determined according to the voltage value of the integral signal . Therefore, the stop of the illumination light and the emission of the maximum light amount can be determined regardless of the circuit that generates the signal. For this reason, even when the hysteresis of the circuit is small or the time constant is large, the light amount setting and the dimming timing can be matched.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
[0014]
This embodiment shows an example in which the illumination light control device of the present invention (hereinafter referred to as an “ilcon device”) is applied to control the luminance of a display panel of a car air conditioner.
[0015]
FIG. 1 is a diagram showing a display panel 20 of a car air conditioner. The display panel 20 is provided with an air conditioner switch 21 for turning the compressor on and off, a fan switch 22 for inputting a blow instruction, an LED 25, and the like. When the air conditioner switch 21 and the fan switch 22 are turned on, the backlight is turned on so that display characters such as A / C can be easily seen. The LED 25 indicates to the user the mode selected by lighting.
[0016]
FIG. 2 is a block diagram showing the configuration of the illumination device according to the present embodiment. FIG. 3 is a diagram showing signals input and output in the configuration shown in FIG. 2, wherein (A) shows the ILCON device signal output from the ILCON device, and (B) shows the integrated signal. .
[0017]
The configuration shown in FIG. 2 includes a dimming dial 1, an integrating circuit 3, a differentiating circuit 5, a microcomputer 7, and a lighting device 9. The light control dial 1 corresponds to the light quantity setting means in the claims, the integration circuit 3 corresponds to the light quantity signal generation means in the claims, the differentiation circuit 5 corresponds to the differential signal generation means, and the microcomputer 7 corresponds to the light control means. It corresponds to.
[0018]
The dimming dial 1 is a dial type switch that sets the luminance of illumination light emitted from the illumination device. The luminance of the illumination light set by the dimming dial 1 is output to the integrating circuit 3 and the differentiating circuit 5 as the illumination control signal 2 shown in FIG. 3A is PWM controlled, and the width of the rectangular wave changes according to the luminance. It should be noted that the illumination control signal 2 in the figure is shown as an inverted signal.
[0019]
The integration circuit 3 to which the ilcon signal 2 is input converts the ilcon signal 2 into an integration signal 4 shown in FIG. Since the peak value of the integrated signal 4 changes according to the width of the illumination signal 2, the luminance set from the peak value of the integrated signal 4 can be detected. Since the peak value of the integration signal 4 depends on the power supply voltage VDD, it is shown as a multiple of VDD (xVDD) in the figure.
[0020]
On the other hand, the differentiation circuit 5 to which the ilcon signal 2 is inputted converts the ilcon signal 2 into a differentiation signal 6 and outputs it. The differential signal 6 is not output not only when the illumination light when the illumination signal 2 is not output is stopped but also while a certain value is output from the illumination signal 2.
[0021]
The microcomputer 7 inputs the integration signal 4 from the A / D port a and inputs the differential signal 6 from the digital port b. Then, the luminance set from the peak value of the integrated signal 4 is detected, and it is detected from the digitally converted differential signal 6 whether or not the differential signal 6 is output.
[0022]
If the differential signal 6 is output as a result of the detection, the microcomputer 7 detects the peak value from the integrated signal 4 and calculates the set luminance so that the luminance of the lighting device 9 becomes the calculated value. adjust. On the other hand, when the differential signal 6 is not output, the microcomputer 7 determines from the peak value of the integrated signal 4 whether to stop the illumination light emission or to set the luminance of the illumination light to the maximum, and the illumination device 9 is controlled to stop the illumination light emission, or to set the illumination light to the maximum brightness.
[0023]
Such stop of illumination light and determination of the maximum luminance by the integration signal 4 do not require checking whether the peak value of the integration signal 4 is the minimum value or the maximum value. For example, a predetermined peak value is determined and this value and This is made possible by determining that the illumination light emission is stopped when the detected peak value is smaller than the predetermined peak value and that the maximum luminance setting is set when the detected peak value is larger than the predetermined peak value.
[0024]
FIG. 4 is a flowchart for explaining the control performed by the above-described Ilcon device according to the present embodiment.
[0025]
The illustrated control is started by turning on the illumination device (S1). When the ILCON device is turned on, the microcomputer 7 first determines that the differential signal 6 is not output due to the PWM signal being set to a constant DC voltage when the illumination light is stopped or the maximum amount of light is emitted (differentiated). Whether there is no signal) is determined (S2). If there is a differential signal 6 as a result of the determination, the illumination signal flag 2 indicates that the illumination light emission is stopped because the illumination signal 2 does not indicate either the emission light emission stop or the maximum luminance setting. Reset is performed (S9), and the highest luminance flag for setting the luminance of the illumination light to the highest value is also reset (S10). Then, the process exits this flowchart and enters the process of obtaining the set value of luminance from the peak value of the integral signal 4.
[0026]
If it is determined in step 2 that there is no differential signal output, the peak value of the integrated signal 4 is detected. If this value is more than half of the power supply voltage VDD (S3), the illumination is stopped. The flag is reset (S7), the highest luminance flag is set (S8), indicating that the highest luminance has been set.
[0027]
On the other hand, if it is determined in step 3 that the peak value of the integrated signal 4 is less than half of the power supply voltage VDD (S3), the illumination stop flag is set (S4), the highest luminance flag is reset, and the illumination light is emitted. The stop is indicated (S5). Thereafter, it is determined whether or not the illumination device is turned on (S6). If the illumination device is turned off, the process is terminated.
[0028]
Although the present embodiment described, the differential signal 6 of Irukon signal 2 Irukon signal 2 is a PWM signal due to be a constant DC voltage during stop or maximum light emission of the illumination light is the differential When the signal is not output from the signal generation means 5, the illumination light emission is stopped or the maximum luminance is determined according to the voltage value of the integration signal 4 of the Ilcone signal 2 . Drunk, and be constant emission stop of the illumination light or the highest luminance judgment regardless when integrals circuit, it is possible to shorten the response time of the Irukon device.
[0029]
Further, when there is no differential signal output, the peak value of the voltage value of the integration signal 4 of the illumination signal signal 2 is half or more of the power supply voltage, or half of whether the illumination light emission is stopped or the maximum luminance is obtained. Judgment is made below. Therefore, even when the hysteresis of the peak value determination is small, it is possible to stably determine the emission stop of illumination light and the maximum luminance.
[0030]
【The invention's effect】
The illumination light control device according to the present invention determines the stop of illumination light and the maximum amount of light emission based on the differential signal generated by the differential signal generation means, and particularly the illumination light when the maximum amount of illumination light is emitted and stopped. Therefore, it is possible to provide an illumination light control device that stabilizes the brightness of the light source and has less operational discomfort.
[Brief description of the drawings]
FIG. 1 is a diagram showing a display panel to which an illumination light control device according to an embodiment of the present invention is applied.
FIG. 2 is a block diagram showing a configuration of an illumination light control apparatus according to an embodiment of the present invention.
3A and 3B are diagrams illustrating signals input and output in the configuration illustrated in FIG. 2, in which FIG. 3A is a diagram illustrating an ILCON signal, and FIG. is there.
FIG. 4 is a flowchart illustrating processing performed by the illumination light control apparatus according to the embodiment of the present invention.
FIG. 5 is a diagram showing the relationship between the brightness of conventional illumination light and the amount of rotation of a dial switch.
[Explanation of symbols]
1 ... Dimming dial (light quantity setting means)
2 ... Ilcon signal 3 ... Integral circuit (light quantity signal generating means)
4 ... Integral signal (signal according to the set light intensity)
5 ... Differentiation circuit (differential signal generation means)
6 ... Differential signal 7 ... Microcomputer (light control means)
9 ... Lighting device

Claims (1)

An illumination light control device that controls the amount of illumination light,
A light amount setting means (1) having a pulse width corresponding to the set light amount, and generating a PWM signal that is a constant DC voltage without outputting a rectangular wave when the illumination light is stopped or the maximum light amount is emitted ;
A light amount signal generating means (3) for generating an integrated signal (4) obtained by integrating the PWM signal output from the light amount setting means (1) ;
Differential signal generation means (5) for generating a differential signal (6) obtained by differentiating the PWM signal output from the light amount setting means (1) ;
While adjusting the amount of voltage values illumination light in accordance with the outputted the integrals signal (4) from the light quantity signal generating means (3), the PWM signal is constant during the illumination light stop or maximum light emission When the differential signal (6) is not output from the differential signal generation means (5) due to the direct current voltage being applied, the illumination light is stopped or the maximum amount of light is emitted according to the voltage value of the integral signal (4). The illumination light control device characterized by comprising a light control means (7) for determining the light intensity.

Images