Detection circuits and detection methods of liquid crystal panels

• US 10,170,026 B2
• Filed: 08/03/2016
• Issued: 01/01/2019
• Est. Priority Date: 06/06/2016
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Zhang, Xianming
• Primary Examiner(s): Bolotin, Dmitriy
• Application Number:
  US15/128,211
• Publication Number:
  US 20180218655A1
• Time in Patent Office: 881 Days
• CPC Class Codes: G02F 1/1309 Repairing; Testing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/027 Arrangements or methods related to powering off a display
• CPC Class Codes: G09G 2360/14 Detecting light within display terminals, e.g. using a single or a plurality of photosensors
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

The present disclosure relates to a detection circuit and a detection method of liquid crystal panels. The detection circuit includes at least one optical sensor configured to detect a brightness of the liquid crystal panel, and to convert the detected brightness into a first voltage, an operational amplifier configured to amplify the first voltage according to a predetermined ratio to generate a second voltage, and a comparison circuit configured to compare the second voltage generated by the operational amplifier with a plurality of reference voltages to generate control signals for shutting down a power of the liquid crystal panel. With such configuration, the power of the liquid crystal panel may be shut down in time when the liquid crystal panel operates abnormally, which avoids more serious issue that may occur.

Claims

1. A detection circuit of liquid crystal panels, comprising:

at least one optical sensor configured to detect brightness of a liquid crystal panel, and to convert the detected brightness into a first voltage;

an operational amplifier configured to amplify the first voltage according to a predetermined ratio to generate a second voltage; and

a comparison circuit configured to compare the second voltage generated by the operational amplifier with a plurality of reference voltages to generate control signals for shutting down power of the liquid crystal panel;

wherein the comparison circuit comprises;

a first comparator that is configured to compare the second voltage with a first reference voltage;

a first switch that is turned on or off in accordance with first control signals outputted by the first comparator;

a second comparator that is configured to compare the second voltage with a second reference voltage;

a second switch that is turned on or off in accordance with second control signals outputted by the second comparator; and

wherein the second reference voltage is greater than the first reference voltage, and the power of the liquid crystal panel is turned off when the first switch is turned on by the first control signals or when the second switch is turned on by the second control signals.

2. The detection circuit as claimed in claim 1, wherein when the second reference voltage is greater than the first reference voltage, the first switch is turned on by the first control signals outputted by the first comparator, and when the second reference voltage is smaller than the first reference voltage, the first switch is turned off by the first control signals outputted by the first comparator;

and

when the second reference voltage is smaller than the second reference voltage, the second switch is turned on by the second control signals outputted by the second comparator, and when the second reference voltage is greater than the second reference voltage, the second switch is turned off by the second control signals outputted by the second comparator.

3. A detection method of liquid crystal panels, comprising:

detecting brightness of a liquid crystal panel and converting the detected brightness into a first voltage by at least one optical sensor;

amplifying the first voltage according to a predetermined ratio to generate a second voltage by an operational amplifier; and

comparing the second voltage generated by the operational amplifier with a plurality of reference voltages by a comparison circuit to generate control signals turning off power of the liquid crystal panel;

wherein the step of comparing the second voltage generated by the operational amplifier with a plurality of reference voltages by a comparison circuit to generate control signals turning off power of the liquid crystal panel further comprises;

comparing the second voltage with a first reference voltage, and turning on or off a first switch by first control signals outputted by a first comparator; and

comparing the second voltage with a second reference voltage, and turning on or off a second switch by second control signals outputted by a second comparator; and

wherein the second reference voltage is greater than the first reference voltage, and the power of the liquid crystal panel is turned off when the first switch is turned on by the first control signals or when the second switch is turned on by the second control signals.

4. The detection method as claimed in claim 3, wherein when the second reference voltage is greater than the first reference voltage, the first switch is turned on by the first control signals outputted by the first comparator, and when the second reference voltage is smaller than the first reference voltage, the first switch is turned off by the first control signals outputted by the first comparator;

and

when the second reference voltage is smaller than the second reference voltage, the second switch is turned on by the second control signals outputted by the second comparator, and when the second reference voltage is greater than the second reference voltage, the second switch is turned off by the second control signals outputted by the second comparator.

5. A detection method of liquid crystal panels, comprising:

detecting brightness of a liquid crystal panel and converting the detected brightness into a first voltage by at least one optical sensor;

amplifying the first voltage according to a predetermined ratio to generate a second voltage by an operational amplifier; and

comparing the second voltage generated by the operational amplifier with a plurality of reference voltages by a comparison circuit to generate control signals turning off power of the liquid crystal panel;

wherein the step of comparing the second voltage generated by the operational amplifier with a plurality of reference voltages by a comparison circuit to generate control signals turning off power of the liquid crystal panel further comprises;

comparing the second voltage with a third reference voltage by a third comparator;

comparing the second voltage with a fourth reference voltage by a fourth comparator; and

executing or calculating third control signals outputted by the third comparator and fourth control signals outputted by the fourth comparator to generate fifth control signals by an OR circuit; and

turning off a third switch by fifth control signals outputted by the OR circuit; and

wherein the fourth reference voltage is greater than the third reference voltage, and when the fifth control signals turn on the third switch, the power of the liquid crystal panel is turned off when the third switch is turned on.

6. The detection method as claimed in claim 5, wherein when the second reference voltage is greater than the third reference voltage, the third switch is turned on by the third control signals outputted by the third comparator, and when the second reference voltage is smaller than the third reference voltage, the third switch is turned off by the third control signals outputted by the third comparator;

and

when the second reference voltage is smaller than the fourth reference voltage, the third switch is turned on by the fourth control signals outputted by the fourth comparator, and when the second reference voltage is greater than the fourth reference voltage, the third switch is turned off by the fourth control signals outputted by the fourth comparator.

7. A detection circuit of liquid crystal panels, comprising:

at least one optical sensor configured to detect brightness of a liquid crystal panel, and to convert the detected brightness into a first voltage;

an operational amplifier configured to amplify the first voltage according to a predetermined ratio to generate a second voltage; and

a comparison circuit configured to compare the second voltage generated by the operational amplifier with a plurality of reference voltages to generate control signals for shutting down power of the liquid crystal panel;

wherein the comparison circuit further comprises;

a third comparator that compares the second voltage with a third reference voltage;

a fourth comparator that compares the second voltage with a fourth reference voltage;

an OR circuit that executes or calculates the third control signals outputted by the third comparator and the fourth control signals outputted by the fourth comparator to generate fifth control signals; and

a third switch that is turned on or off by the fifth control signals outputted by the OR circuit; and

wherein the fourth reference voltage is greater than the third reference voltage, and when the fifth control signals turns on the third switch, the power of the liquid crystal panel is turned off when the third switch is turned on.

8. The detection circuit as claimed in claim 7, wherein when the second reference voltage is greater than the third reference voltage, the third switch is turned on by the third control signals outputted by the third comparator, and when the second reference voltage is smaller than the third reference voltage, the third switch is turned off by the third control signals outputted by the third comparator;

and

when the second reference voltage is smaller than the fourth reference voltage, the third switch is turned on by the fourth control signals outputted by the fourth comparator, and when the second reference voltage is greater than the fourth reference voltage, the third switch is turned off by the fourth control signals outputted by the fourth comparator.