CN211654271U - Liquid crystal display backlight brightness adjusting device adaptive to ambient light - Google Patents
Liquid crystal display backlight brightness adjusting device adaptive to ambient light Download PDFInfo
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- CN211654271U CN211654271U CN202020395742.XU CN202020395742U CN211654271U CN 211654271 U CN211654271 U CN 211654271U CN 202020395742 U CN202020395742 U CN 202020395742U CN 211654271 U CN211654271 U CN 211654271U
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Abstract
The utility model discloses a liquid crystal display screen luminance adjusting device in a poor light of self-adaptation ambient light includes PWM input module, drive module and LED lamp strip in a poor light, PWM input module input PWM signal, drive module receives PWM signal in a poor light and drives LED lamp strip luminous, the electricity is connected with current-limiting resistor between drive module and the LED lamp strip in a poor light, be equipped with the illumination compensation module between current-limiting resistor and the LED lamp strip, the illumination compensation module includes photosensitive sensing drive module, luminance/current detection processing module and luminance partition compensation control module. The module can be used for rapidly and accurately adjusting the brightness of the liquid crystal display screen according to ambient light.
Description
Technical Field
The utility model relates to a display screen technical field, concretely relates to LCD screen brightness control unit that is shaded of self-adaptation ambient light.
Background
Along with different application environment brightness, the display brightness of the liquid crystal screen required by human eyes is different, the brightness needs to be increased under bright environment light, and the brightness needs to be decreased under dark and weak environment light, so that the balance between the screen visual definition and the human eye comfort level is obtained. The display brightness of a common LCD (liquid crystal display) screen on the market depends on an LED backlight display module at the back of the screen, and the brightness of an LED lamp tube is determined by the current passing through an LED lamp. The LED backlight brightness regulation scheme of the liquid crystal display screen is that DC-DC boost voltage is added with PWM to regulate LED backlight current, then the maximum current is determined by a current-limiting resistor, and the current is directly related to brightness. The traditional manual brightness adjustment method has a lot of inconvenience in practical application, and particularly on vehicle-mounted display, driving potential safety hazards are more likely to be brought, so that the brightness adjustment requirement of self-adaptive ambient light is met.
In order to adapt to the ambient light brightness, a photosensitive sensor is usually used to detect the illumination brightness change and convert the optical signal change into an electrical signal change, and a photo resistor, a photo diode, and the like are commonly used. The photoresistors have time delay characteristics, when the photoresistors are irradiated by pulse light, the photocurrent is stabilized after a period of time, and the photocurrent cannot be immediately zero after the irradiation is stopped, so that the time delay of most of the photoresistors is larger, and the photoresistors are not used in occasions requiring quick response.
A photodiode, also called a photodiode, is a photoelectric conversion device that converts a change in received light into a change in current. When no light is irradiated, the volt-ampere characteristic of the photosensitive diode is the same as that of a common diode, and the photosensitive diode is equivalent to a constant current source corresponding to certain illumination intensity. The volt-ampere characteristic of the photosensitive diode is equivalent to that of a common diode which is translated downwards, when the bias voltage is zero, the photosensitive diode has light current output, and the illumination characteristic of the photosensitive diode is also in good linearity. The utility model aims at providing an utilize photosensitive diode to realize self-adaptation ambient light's LCD screen brightness control device that is shaded.
Disclosure of Invention
For overcoming the not enough of prior art, the utility model provides a liquid crystal display backlight brightness control device of self-adaptation ambient light, it can be according to the quick luminance of accurately adjusting liquid crystal display of ambient light.
For realizing the above-mentioned purpose, the utility model discloses a LCD screen brightness control device in a poor light of self-adaptation ambient light, including PWM input module, drive module and LED lamp strip are shaded, PWM input module input PWM signal, drive module receives PWM signal and drives LED lamp strip is luminous in a poor light, and the electricity is connected with current-limiting resistor between drive module and the LED lamp strip in a poor light, is equipped with the luminance compensation module between current-limiting resistor and the LED lamp strip, and the luminance compensation module includes photosensitive sensing drive module, luminance/current detection processing module and luminance subregion compensation control module.
Furthermore, the photosensitive sensing driving module comprises a photosensitive diode, 12V power supply voltage is added to the positive pole of the photosensitive diode, the negative pole of the photosensitive diode is electrically connected with a sampling resistor, one end, far away from the photosensitive diode, of the sampling resistor is grounded, reverse current of the photosensitive diode generates sampling voltage on the sampling resistor, an amplifier is electrically connected between the photosensitive diode and the sampling resistor, 12V power supply voltage is added to the amplifier, and the sampling voltage is amplified by the amplifier.
Furthermore, a first variable resistor is arranged on the amplifier and used for setting the amplification factor of the sampling voltage.
Furthermore, the brightness/current detection processing module comprises a double comparator, a 12V power supply voltage is added to the double comparator, the output end of the amplifier is electrically connected to the input end of the double comparator, the access end of the double comparator is also electrically connected to a weak light threshold and a strong light threshold, and two output ends of the double comparator respectively output a strong light compensation signal Q and a weak light compensation signal R.
Furthermore, a second variable resistor is arranged on the weak light threshold, a 12V power supply voltage is added to one end of the second variable resistor, the other end of the second variable resistor is grounded, the second variable resistor is used for setting the weak light threshold voltage, a third variable resistor is arranged on the strong light threshold, a 12V power supply voltage is added to one end of the third variable resistor, the other end of the third variable resistor is grounded, and the third variable resistor is used for setting the strong light threshold voltage.
Further, the luminance partition compensation control module comprises a weak light compensation module and a strong light compensation module, wherein:
the weak light compensation module comprises a weak light control resistor connected between the LED light bar and the current-limiting resistor, a weak light NMOS transistor switch is connected to the weak light control resistor, the D pole of the weak light NMOS transistor switch is electrically connected with the weak light control resistor, the S pole of the weak light NMOS transistor switch is grounded, the G-level of the weak light NMOS transistor switch is electrically connected with a weak light buffer resistor, and the weak light resistor receives and transmits a weak light compensation signal R;
the highlight compensation module is connected with highlight NMOS transistor switch including the highlight control resistance of connection between LED lamp strip and current-limiting resistor on the highlight control resistance, and the D utmost point and the highlight control resistance electricity of highlight NMOS transistor switch are connected, and the S utmost point ground connection of highlight NMOS transistor switch, the G level electricity of highlight NMOS transistor switch are connected with highlight buffer resistance, and transmission highlight compensation signal Q is received to highlight buffer resistance.
The utility model discloses a liquid crystal display screen brightness control device in a poor light of self-adaptation ambient light utilizes the good linear photoelectric characteristic of photodiode, detects and receives ambient light and changes, turns into the current variation with luminance change, and the highlight threshold through enlargiing and setting for, weak light threshold is relatively, obtains control signal, send the luminance compensation module, superposes on the drive module in a poor light at last, realizes the self-adaptation compensation control liquid crystal display screen display luminance to ambient light.
Drawings
The invention will be further described and illustrated with reference to the accompanying drawings.
Fig. 1 is a block diagram of the structure of a brightness compensation module and an LED light bar in a backlight brightness adjusting device of a liquid crystal display panel according to a preferred embodiment of the present invention;
FIG. 2 is a circuit diagram of the PWM input module, the backlight driving module, the LED light bar and the luminance partition compensation control module;
fig. 3 is a circuit diagram of the photosensitive sensing driving module and the brightness/current detection processing module.
Reference numerals: 1. a photosensitive sensing driving module; 11. a photodiode; 12. sampling a resistor; 13. an amplifier; 14. a first variable resistor; 2. a brightness/current detection processing module; 21. a dual comparator; 22. a weak light threshold; 221. a second variable resistor; 23. a strong light threshold; 231. a variable resistor III; 3. a brightness partition compensation control module; 31. a low-light control resistor; 32. a weak light NMOS transistor switch; 33. a weak light buffer resistor; 34. a strong light control resistor; 35. a hard light NMOS transistor switch; 36. a strong light buffer resistor; 4. an LED light bar; 5. a current limiting resistor.
Detailed Description
The technical solution of the present invention will be more clearly and completely explained by the description of the preferred embodiments of the present invention with reference to the accompanying drawings.
As shown in fig. 1 and fig. 2, the utility model discloses preferred embodiment's self-adaptation ambient light's LCD screen brightness control device that is shaded, including PWM input module, drive module and LED lamp strip 4 in a poor light, PWM input module input PWM signal, drive module receives PWM signal and drives LED lamp strip 4 in a poor light and give out light. The current limiting resistor 5 is electrically connected between the backlight driving module and the LED light bar 4, and the current limiting resistor 5 determines the maximum working current of the LED light bar 4 and also determines the maximum brightness of the LED light bar 4. On the premise of constant-voltage power supply of the LED light bar 4, the current is changed by changing the current limiting resistor 5, so that the effect of changing the backlight brightness can be achieved, therefore, a brightness compensation module is arranged between the current limiting resistor 5 and the LED light bar 4, and the brightness compensation module automatically compensates the brightness by changing the resistance value of the current limiting resistor 5. The brightness compensation module comprises a photosensitive sensing driving module 1, a brightness/current detection processing module 2 and a brightness partition compensation control module 3.
As shown in fig. 3, the light-sensitive sensing driving module 1 includes a photodiode 11, a 12V power supply voltage is applied to a positive electrode of the photodiode 11, a sampling resistor 12 is electrically connected to a negative electrode of the photodiode 11, one end of the sampling resistor 12, which is far away from the photodiode 11, is grounded, a reverse current of the photodiode 11 generates a sampling voltage on the sampling resistor 12, an amplifier 13 is electrically connected between the photodiode 11 and the sampling resistor 12, the 12V power supply voltage is applied to the amplifier 13, the amplifier 13 amplifies the sampling voltage, and since an illumination characteristic of the photodiode 11 has good linearity, a linearly-varying current and voltage corresponding to an ambient light brightness can be obtained. The amplifier 13 is provided with a first variable resistor 14, and the first variable resistor 14 is used for setting the amplification factor of the sampling voltage. The photodiode 11 receives the ambient light change, generates a small change current, forms a changed sampling voltage on the sampling resistor 12, amplifies the voltage by the amplifier 13, and adjusts the amplification factor by the variable resistor.
As shown in fig. 3, the brightness/current detection processing module 2 includes a dual comparator 21, a 12V power supply voltage is applied to the dual comparator 21, an output terminal of the amplifier 13 is electrically connected to an input terminal of the dual comparator 21, an input terminal of the dual comparator 21 is further electrically connected to a weak light threshold 22 and a strong light threshold 23, and two output terminals of the dual comparator 21 respectively output a strong light compensation signal Q and a weak light compensation signal R. The dual comparator 21 detects the voltage input by the amplifier 13, and when the detected voltage is between the strong light threshold 23 and the weak light threshold 22, the dual comparator 21 outputs the weak light compensation R as a high level, the strong light compensation Q as a low level, and the module body does not perform compensation. When the detection voltage is below the weak light threshold 22, the dual comparator 21 outputs the weak light compensation R as a low level, the strong light compensation Q as a low level, the module body opens the compensation weak light, the current limiting resistor 5 is increased, the current is reduced, and the backlight brightness is reduced. When the detection voltage is above the strong light threshold 23, the dual comparator 21 outputs weak light compensation Q as a high level, strong light compensation R as a high level, and the module body opens the compensation strong light, reduces the current-limiting resistor 5, increases the current, and increases the backlight brightness.
As shown in fig. 3, a second variable resistor 221 is disposed on the weak light threshold 22, one end of the second variable resistor 221 is applied with a 12V power supply voltage, and the other end is grounded, and the second variable resistor 221 is used for setting the voltage of the weak light threshold 22. The strong light threshold 23 is provided with a variable resistor three 231, one end of the variable resistor three 231 is provided with a 12V power supply voltage, the other end of the variable resistor three 231 is grounded, and the variable resistor three 231 is used for setting the voltage of the strong light threshold 23.
As shown in fig. 2, the luminance partition compensation control module 3 includes a weak light compensation module and a strong light compensation module. The weak light compensation module comprises a weak light control resistor 31 connected between the LED light bar 4 and the current limiting resistor 5, a weak light NMOS transistor switch 32 is connected to the weak light control resistor 31, a D pole of the weak light NMOS transistor switch 32 is electrically connected with the weak light control resistor 31, an S pole of the weak light NMOS transistor switch 32 is grounded, a G pole of the weak light NMOS transistor switch 32 is electrically connected with a weak light buffer resistor 33, and the weak light buffer resistor 33 receives a weak light compensation signal R; the strong light compensation module is including connecting the strong light control resistance 34 between LED lamp strip 4 and current-limiting resistor 5, is connected with strong light NMOS transistor switch 35 on the strong light control resistance 34, and the D utmost point and the strong light control resistance 34 electricity of strong light NMOS transistor switch 35 are connected, and the S utmost point ground connection of strong light NMOS transistor switch 35, the G level electricity of strong light NMOS transistor switch 35 are connected with strong light buffer resistance 36, and strong light buffer resistance 36 receives strong light compensation signal Q.
The logic for ambient light partitioning is: the method is characterized in that the ambient brightness is simply divided into a weak light area, a normal area and a strong light area, and compensation control is respectively carried out, and the method specifically comprises the following steps:
normal zone: the weak light control resistor 31 is controlled to be grounded, the strong light control resistor 34 is disconnected, and the current limiting resistor 5 and the weak light control resistor 31 are connected in parallel to form the current limiting resistor 5.
Weak light region: the weak light control resistor 31 is controlled to be switched off, the strong light control resistor 34 is kept switched off, only the current limiting resistor 5 is increased for the current limiting resistor 5, the current is reduced, and the brightness is reduced.
Strong light area: the weak light control resistor 31 is controlled to maintain normal grounding, the strong light control resistor 34 is grounded, the current limiting resistor 5, the weak light control resistor 31 and the strong light control resistor 34 are connected in parallel to the current limiting resistor 5 to reduce, the current is increased, and the brightness is increased.
The utility model discloses a liquid crystal display screen brightness control device in a poor light of self-adaptation ambient light carries out the subregion with ambient light brightness according to the power, utilize the good linear photoelectric characteristic of photodiode 11, detect and receive ambient light and change, turn into the current variation with luminance change, highlight threshold 23, the weak light threshold 22 comparison of enlarging and setting for, obtain control signal, send the luminance compensation module, superpose on original drive module in a poor light at last, realize the self-adaptation compensation control liquid crystal display screen display luminance to ambient light.
The above detailed description merely describes the preferred embodiments of the present invention and does not limit the scope of the present invention. Without departing from the design concept and spirit scope of the present invention, the ordinary skilled in the art should belong to the protection scope of the present invention according to the present invention provides the text description and drawings to the various modifications, replacements and improvements made by the technical solution of the present invention. The scope of protection of the present invention is determined by the claims.
Claims (6)
1. A liquid crystal display backlight brightness adjusting device adaptive to ambient light comprises a PWM input module, a backlight driving module and an LED light bar, wherein the PWM input module inputs a PWM signal, the backlight driving module receives the PWM signal and drives the LED light bar to emit light, and a current limiting resistor is electrically connected between the backlight driving module and the LED light bar.
2. The device as claimed in claim 1, wherein the photosensitive sensing driving module comprises a photodiode, a 12V supply voltage is applied to an anode of the photodiode, a sampling resistor is electrically connected to a cathode of the photodiode, an end of the sampling resistor away from the photodiode is grounded, a reverse current of the photodiode generates a sampling voltage on the sampling resistor, an amplifier is electrically connected between the photodiode and the sampling resistor, a 12V supply voltage is applied to the amplifier, and the amplifier amplifies the sampling voltage.
3. The backlight brightness adjusting device of LCD screen of adaptive ambient light as claimed in claim 2, wherein the amplifier is provided with a first variable resistor for setting the amplification factor of the sampling voltage.
4. The backlight brightness adjusting device of the lcd with adaptive ambient light as claimed in claim 2, wherein the brightness/current detection processing module comprises a dual comparator, a 12V power supply voltage is applied to the dual comparator, the output terminal of the amplifier is electrically connected to the input terminal of the dual comparator, the input terminal of the dual comparator is further electrically connected to a weak light threshold and a strong light threshold, and two output terminals of the dual comparator respectively output a strong light compensation signal Q and a weak light compensation signal R.
5. The backlight brightness adjusting apparatus for an adaptive ambient light lcd of claim 4, wherein a second variable resistor is disposed on the weak light threshold, a 12V power supply voltage is applied to one end of the second variable resistor, the other end of the second variable resistor is grounded, the second variable resistor is used for setting the weak light threshold voltage, a third variable resistor is disposed on the strong light threshold, a 12V power supply voltage is applied to one end of the third variable resistor, the other end of the third variable resistor is grounded, and the third variable resistor is used for setting the strong light threshold voltage.
6. The backlight brightness adjusting device of LCD screen of adaptive environment light as claimed in claim 4, wherein the brightness partition compensation control module comprises a weak light compensation module and a strong light compensation module, wherein:
the weak light compensation module comprises a weak light control resistor connected between the LED light bar and the current-limiting resistor, a weak light NMOS transistor switch is connected to the weak light control resistor, the D pole of the weak light NMOS transistor switch is electrically connected with the weak light control resistor, the S pole of the weak light NMOS transistor switch is grounded, the G pole of the weak light NMOS transistor switch is electrically connected with a weak light buffer resistor, and the weak light buffer resistor receives and transmits a weak light compensation signal R;
the highlight compensation module is including connecting the highlight control resistance between LED lamp strip and current-limiting resistor, be connected with highlight NMOS transistor switch on the highlight control resistance, the D utmost point and the highlight control resistance electricity of highlight NMOS transistor switch are connected, the S utmost point ground connection of highlight NMOS transistor switch, the G level electricity of highlight NMOS transistor switch is connected with highlight buffer resistance, transmission highlight compensation signal Q is received to highlight buffer resistance.
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| CN202020395742.XU CN211654271U (en) | 2020-03-25 | 2020-03-25 | Liquid crystal display backlight brightness adjusting device adaptive to ambient light |
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| CN202020395742.XU CN211654271U (en) | 2020-03-25 | 2020-03-25 | Liquid crystal display backlight brightness adjusting device adaptive to ambient light |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112767886A (en) * | 2021-01-18 | 2021-05-07 | 惠科股份有限公司 | Backlight adjusting system, adjusting method thereof and display device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112767886A (en) * | 2021-01-18 | 2021-05-07 | 惠科股份有限公司 | Backlight adjusting system, adjusting method thereof and display device |
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