DISPLAY DEVICE AND METHOD FOR DISPLAYING IMAGE

A display device includes a first display driver circuit that outputs a first gamma reference voltage to a first display panel, and a second display driver circuit that outputs a second gamma reference voltage to a second display panel different from the first display panel, and determines the difference between the first gamma reference voltage and the second gamma reference voltage, and keeps outputting the second gamma reference voltage when the difference is smaller than a first reference value, and changes the second gamma reference voltage when the second gamma reference voltage is less than the first gamma reference voltage and the difference is equal to or greater than the first reference value.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0090663 filed in the Korean Intellectual Property Office on Jul. 12, 2023, the entire content of which is incorporated herein by reference.

BACKGROUND

With the development of information and communication technologies, information related to various types of images is being distributed. Therefore, electronic devices such as automobile devices, smart phones, and artificial reality systems include display devices for conveying information on images to users. As the amount of data required to be processed to provide information on images has increased, high-performance display devices have been used.

Display devices may generate and emit light, using various elements. Such display devices may perform various operations in order to improve the qualities of images to be displayed by the display devices.

SUMMARY

The present disclosure generally relates to a display device including two display panels for displaying images with the same quality.

A display device according to some implementations includes a first display driver circuit that outputs a first gamma reference voltage to a first display panel, and a second display driver circuit that outputs a second gamma reference voltage to a second display panel different from the first display panel, and determines the difference between the first gamma reference voltage and the second gamma reference voltage, and keeps outputting the second gamma reference voltage when the difference is smaller than a first reference value, and changes the second gamma reference voltage when the second gamma reference voltage is lower than the first gamma reference voltage and the difference is equal to or greater than the first reference value.

A display device according to some implementations includes a first display panel that emits first image light based on first image data, using a first gamma reference voltage, a second display panel that emits second image light based on second image data, using a second gamma reference voltage, and a processor that generates the first image data and the second image data, and controls the gamma reference voltage of the first display panel or the second display panel, on the basis of the difference between the first gamma reference voltage and the second gamma reference voltage.

An image display method of display panels according to some implementations includes comparing, by a first display panel, a first gamma reference voltage that is used in the first display panel with a second gamma reference voltage that is used in a second display panel, changing the first gamma reference voltage when the first gamma reference voltage is less than the second gamma reference voltage, and instructing the second display panel to change the second gamma reference voltage when the second gamma reference voltage is less than the first gamma reference voltage.

DETAILED DESCRIPTION

In the following detailed description, only certain implementations of the present disclosure have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described implementations may be modified in various different ways, all without departing from the spirit or scope of the present disclosure.

Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. In the flow chart described with reference to the drawings, the order of operations may be changed, several operations may be combined, an operation may be divided, and some operations may not be performed.

Further, expressions written in the singular forms can be comprehended as the singular forms or plural forms unless clear expressions such as “a”, “an”, or “single” are used. Terms including an ordinal number, such as first and second, are used for describing various constituent elements, but the constituent elements are not limited by the terms. The terms are used only to discriminate one constituent element from other constituent elements.

FIG.1is a block diagram for explaining a display system according to some implementations.

Referring toFIG.1, a display system10according to some implementations may provide artificial reality systems, such as virtual reality (VR) systems, augmented reality (AR) systems, mixed reality (MR) systems, hybrid reality systems, or combinations of some of them, and/or derivative systems thereof. Artificial reality systems may be implemented on a variety of platforms including head-mounted displays (HMDs), mobile devices, computing systems, or other hardware platforms capable of providing artificial reality contents to one or more viewers.

The display system10includes a display device110and a processor120. The processor120may be a host device for managing the display device110. The processor120may generate first image data for the left eye of a user, and second image data for the right eye. The processor120may transmit the first and second image data as image data IS to the display device110. Depending on implementation, the first image data and the second image data may be the same, or may be different. The display device110may receive the image data IS transmitted from the processor120, and display images according to the image data IS. The display device110may display two-dimensional or three-dimensional images to users.

The display device110according to some implementations includes a first display panel111, a second display panel114, an optical system117, and an eye tracking sensor118. The first display panel111and the second display panel114may be mounted in the display device110so as to be physically separated. For example, in the display device110, the first display panel111may be disposed for the left eye of a user, and the second display panel114may be disposed for the right eye of the user. The optical system117may optically process image light emitted from the first display panel111and the second display panel114, and output the processed light to the user's eyes. The optical system117may reflect, refract, and correct image light. For example, the optical system117may include a first optical system that processes image light of the first display panel111, and a second optical system that processes image light of the second display panel114. The first and second optical systems may be disposed in the display device110so as to be physically separated.

The first and second display panels111and114may display images to the user according to image data IS received from the processor120. For example, the first display panel111may display images based on first image data of the image data IS, and the second display panel114may display images based on second image data of the image data IS. The first display panel111may display images to the left eye of a user, and the second display panel114may display images to the right eye of the user. Depending on implementation, the first display panel111may be implemented to display images to the right eye of a user, and the second display panel114may be implemented to display images to the left eye of the user. The first and second display panels111and114may be implemented with liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, inorganic light-emitting diode (ILED) displays, micro light-emitting diode (μLED) displays, micro OLED (μOLED) displays, active matrix OLED displays (AMOLEDs), transparent OLED (TOLED) displays, etc. In some implementations, the display device110may further include a power supply circuit, such as a DC-to-DC converter, that supplies drive voltages to the first display panel111, the second display panel114, the optical system117, and the eye tracking sensor118.

The first display panel111includes a pixel array112and a driver circuit113. The first display panel111may have a backplane structure in which the pixel array112and the driver circuit113are disposed on a silicon substrate (silicon semiconductor substrate). For example, the first display panel111may include a pixel array112and a driver circuit113on a complementary metal-oxide-semiconductor (CMOS) wafer.

The pixel array112may include a plurality of pixels, and a plurality of gate lines and a plurality of source lines coupled to the plurality of pixels, respectively. In some implementations, the plurality of pixels may emit light of predominant colors such as red, green, blue, white, or yellow.

The driver circuit113may generate signals to drive the pixel array112on the basis of first image data of image data IS received from the processor120. Signals to drive the pixel array112may be transmitted to the plurality of pixels through the plurality of gate lines and the plurality of source lines. In some implementations, the driver circuit113may generate data signals and gate signals to drive the plurality of pixels included in the pixel array112, and provide the data signals and the gate signals to the plurality of pixels. The driver circuit113may generate a gamma reference voltage, and generate a plurality of gamma voltages on the basis of the gamma reference voltage. The driver circuit113may generate a plurality of data signals on the basis of the plurality of gamma voltages. At this time, the processor120may determine whether a first gamma reference voltage which is used by the driver circuit113of the first display panel111is the same as a second gamma reference voltage which is used by a driver circuit116of the second display panel114, or not. The plurality of pixels included in the pixel array112may emit image light based on signals provided by the driver circuit113.

The second display panel114may include constituent elements similar to those in the first display panel111, and perform an operation similar to that of the first display panel111. The second display panel114includes a pixel array115and the driver circuit116. The contents related to the pixel array112and the driver circuit113may be applied similarly to the pixel array115and the driver circuit116, so a description of the same contents will not be made.

The first and second display panels111and114may operate to generate the same gamma reference voltage. The first and second display panels111and114may monitor gamma reference voltages. For example, the first display panel111may generate a first gamma reference voltage and use it, and the second display panel114may generate a second gamma reference voltage and use it. The first display panel111may receive the second gamma reference voltage from the second display panel114, and compare the first gamma reference voltage and the second gamma reference voltage. The first display panel111may include an analog-to-digital converter (ADC) for comparing the first gamma reference voltage and the second gamma reference voltage. In this case, the first display panel111that compares the gamma reference voltages may be referred to as the master panel, and the second display panel114that transmits its own gamma reference voltage to another display panel (i.e., the first display panel111) may be referred to as the slave panel. The master panel and the slave panel may be determined in advance, or may be designated by the processor120. In some implementations, the processor120may change the master panel and the slave panel even while the first and second display panels111and114emit image light. In some implementations, the processor120may monitor the first and second gamma reference voltages of the first and second display panels111and114, and set a display panel that generates a higher gamma reference voltage, as the master panel.

The first display panel111may keep generating the first gamma reference voltage when the first and second gamma reference voltages are the same or the difference between the first and second gamma reference voltages is smaller than a first reference value. Similarly, the second display panel114may keep generating the second gamma reference voltage.

The first display panel111may amplify the first gamma reference voltage by a predetermined level when the first gamma reference voltage is less than the second gamma reference voltage and the difference between the first and second gamma reference voltages is in a range equal to or greater than the first reference value and smaller than a second reference value. In other words, the first display panel111may generate data signals based on the amplified gamma reference voltage. The second display panel114may keep generating the second gamma reference voltage.

The first display panel111may transmit difference data DF to the processor120when the first gamma reference voltage is higher than the second gamma reference voltage and the difference between the first and second gamma reference voltages is in the range equal to or greater than the first reference value and smaller than the second reference value. The processor120may transmit a drive control signal CTRL to the second display panel114on the basis of the difference data DF. The second display panel114may amplify the second gamma reference voltage by a predetermined level on the basis of the drive control signal CTRL. In other words, the second display panel114may generate data signals based on the amplified gamma reference voltage. The first display panel111may keep generating the first gamma reference voltage.

The first display panel111may transmit the difference data DF to the processor120when the difference between the first and second gamma reference voltages is equal to or greater than the second reference value. The second reference value may be greater than the first reference value. The processor120may perform control based on the difference data DF such that the first and second display panels111and114use the same gamma reference voltage. For example, when the first gamma reference voltage is higher than the second gamma reference voltage, the processor120may perform control such that the second display panel114uses the first gamma reference voltage, not the second gamma reference voltage. In other words, the processor120may transmit a drive control signal CTRL to the first and second display panels111and114, and the first and second display panels111and114may change electrical wiring on the basis of the drive control signal CTRL by opening and closing internal switches, such that they share the first gamma reference voltage. The same description may be applied even when the second gamma reference voltage is higher than the first gamma reference voltage. In some implementations, the range for magnitude comparison with the difference between the first and second gamma reference voltages may include at least one of the first reference value and the second reference value, or may not include at least one of them. In other words, the range may be either a range equal to or greater than at least one of them, or a range equal to or smaller than at least one of them, or may be a range exceeding at least one of them or a range of smaller than at least one of them.

In some implementations, the first and second display panels111and114may be set so as to output the same gamma reference voltage, before emitting image light. In some implementations, the first and second display panels111and114may be set so as to output the same gamma reference voltage in real time while emitting image light.

As described above, the first and second display panels111and114may generate the same gamma reference voltage and output data signals having the same level, whereby the display device110may output images having the same luminance level corresponding to the same gray level to both eyes of a user, such that the user can view the images with high quality.

Images which are displayed on the first and second display panels111and114can be visually recognized by the eyes of the user through the optical system117. In some implementations the optical system117may optically display image contents or magnify image light received from the first and second display panels111and114, respectively, and correct optical errors associated with the image light, and provide the corrected image light to a user. For example, the optical system117may include a substrate, optical waveguides, apertures, Fresnel lenses, convex lenses, concave lenses, filters, input/output couplers, or other arbitrary suitable optical elements that may affect image light which is emitted from the first and second display panels111and114.

The eye tracking sensor118may track the positions and movements of the eyes of a user. Eye tracking may refer to determining the positions of eyes, including the orientations and positions of the eyes, relative to the display device110. In some implementations, the eye tracking sensor118may include an imaging system for imaging one or more eyes. In some implementations, the eye tracking sensor118may include a light emitter that generates light directed at eyes such that light reflected by the eyes can be captured by the imaging system. The eye tracking sensor118may transmit eye tracking data ED to the processor120.

The processor120may be a computing device or system that externally controls the display device110such that images desired by a user are displayed on the pixel arrays112and115. The processor120may transmit image data IS according to a content to be presented to a user, to the display device110. In some implementations, the processor120may render a content generated during execution of an application, into image data IS containing a plurality of areas having different display qualities. For example, the image according to the image data IS may include a first area and a second area, and the first area may be rendered at a first quality (for example, high definition), and the second area around the first area may be rendered at a second quality (for example, low definition). The processor120may render image data IS on the basis of eye tracking data ED received from the display device110. The processor120may receive eye tracking data ED from the eye tracking sensor118, and determine the positions of the eyes of the user on the basis of the eye tracking data. For example, the processor may render a first area corresponding to the positions of the eyes of the user, at a first quality, and render a second area surrounding the first area, at a second quality.

The processor120may transmit a drive control signal CTRL to the display device110. The drive control signal CTRL may contain control instructions, setting data, and the like to control the driver circuits113and116and the optical system117. In some implementations, the drive control signal CTRL may contain an opening/closing instruction signal that instructs to open or close the switches in the first and second display panels111and114. In some implementations, the drive control signal CTRL may contain a selection instruction signal that instructs multiplexers in the first and second display panels111and114to select any one gamma reference voltage. In some implementations, the drive control signal CTRL may contain an amplification instruction signal to instruct the first display panel111or the second display panel114to amplify a gamma reference voltage by a predetermined level. In some implementations, the drive control signal CTRL may contain area instruction data that instructs a plurality of areas of an image according to image data IS.

Further, the first and second display panels111and114according to some implementations may be implemented so as to be included not only in an artificial reality system such as the display system10but also in a tiled-display or the like in which a plurality of display panels operates as one display system.

FIG.2is a circuit diagram for explaining the operation of a display device according to some implementations.

Referring toFIG.2, a display device50according to some implementations includes a first driver circuit200and a second driver circuit300. The display device50may emit image light under the control of the processor150. InFIG.2, for explaining the operation of the display device50, only some constituent elements are shown, but the display device50may further include constituent elements for displaying images, such as a pixel array, a power source, etc.

The processor150may transmit first image data to the first driver circuit200, and transmit second image data to the second driver circuit300. The first driver circuit200may generate a first data signal for images to be displayed to the left eye of a user, on the basis of the first image data, and the second driver circuit300may generate a second data signal for images to be displayed to the right eye of the user, on the basis of the second image data.

The first driver circuit200may generate a first gamma reference voltage VG1, and generate a first data signal on the basis of the first gamma reference voltage VG1. The first driver circuit200includes a controller (CTRL)210, a voltage generator (RVGEN)220, a multiplexer (MUX)230, a buffer240, an analog-to-digital converter (ADC)250, a source driver260, and a plurality of switches271to273. For example, the plurality of switches271to273may be transistors, and the processor150may apply an instruction signal to the gates of the transistors such that the plurality of switches271to273are turned on or off.

The voltage generator220may generate a first gamma reference voltage VG1. The voltage generator220may receive a drive voltage from the outside (for example, a power supply circuit), and generate a first gamma reference voltage VG1based on the drive voltage. The voltage generator220may change the magnitude of the first gamma reference voltage VG1on the basis of a control signal CT1of the controller210. In some implementations, the voltage generator220may output a control signal CT1on the basis of data received from the analog-to-digital converter250. In some implementations, the voltage generator220may output a control signal CT1on the basis of a drive control signal received from the processor150.

The multiplexer230may receive at least one of a first gamma reference voltage VG1and a second gamma reference voltage VG2, and a selection signal muxsel1. For example, in a general situation or a normal situation, the controller210may output a selection signal muxsel1at a first level, and the multiplexer230may receive the first gamma reference voltage VG1and the first-level selection signal muxsel1. A normal situation may be understood as a situation where the difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2is relatively small. The multiplexer230may transfer the first gamma reference voltage VG1to the buffer240on the basis of the first-level selection signal muxsel1. In an abnormal situation, the controller210may output the selection signal muxsel1at a second level, and the second driver circuit300may transfer the second gamma reference voltage VG2to the multiplexer230, and the multiplexer230may receive the first gamma reference voltage VG1, the second gamma reference voltage VG2, and the second-level selection signal muxsel1. The second level is a logic level different from the first level, and when the first level is a logic high level, the second level is a logic low level, and vice versa. An abnormal situation may be understood as a situation where the difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2is relatively large. The processor150may close the switch271and a switch373, whereby the second driver circuit300may transfer the second gamma reference voltage VG2to the multiplexer230through the switch271and the switch373. The multiplexer230may transfer the second gamma reference voltage VG2to the buffer240in response to the second-level selection signal muxsel1.

The buffer240may output the first gamma reference voltage VG1or the second gamma reference voltage VG2. In some implementations, the output voltage of the buffer240(for example, the first gamma reference voltage VG1or the second gamma reference voltage VG2) may be input to the source driver260. In some implementations, the output voltage of the buffer240(for example, the first gamma reference voltage VG1) may be input to the analog-to-digital converter250through the switch272. In some implementations, the output voltage of the buffer240(for example, the second gamma reference voltage VG2) may be input to an analog-to-digital converter350of the second driver circuit300through the switch273and a switch371. The switches271to273may be closed and opened in response to an opening/closing instruction signal of the processor150. Transmission of an opening/closing instruction signal by the processor150may be understood as transmission of the opening/closing instruction signal at a high level. For example, the switches271to273may be closed in response to the opening/closing instruction signal at the high level, and may be opened in response to the opening/closing instruction signal at the low level.

The analog-to-digital converter250may receive the first gamma reference voltage VG1and the second gamma reference voltage VG2. The analog-to-digital converter250may generate first and second sampling values by sampling the first and second gamma reference voltages VG1and VG2, respectively. The analog-to-digital converter250may output the first and second sampling values to the controller210.

The controller210may compare the first sampling value and the second sampling value. For example, the controller210may perform magnitude comparison on the first sampling value and the second sampling value. The controller210may compare the sampling values with reference values, and output different signals depending on the comparison results. The operation of the controller210will be described below with reference toFIG.4toFIG.9.

The second driver circuit300may generate a second gamma reference voltage VG2, and generate a second data signal based on the second gamma reference voltage VG2. The second driver circuit300includes a controller310, a voltage generator320, a multiplexer330, a buffer340, the analog-to-digital converter350, a source driver360, and a plurality of switch371to373. The controller310, the voltage generator320, the multiplexer330, the buffer340, the analog-to-digital converter350, the source driver360, and the plurality of switches371to373may be substantially similar in structure to the controller210, the voltage generator220, the multiplexer230, the buffer240, the analog-to-digital converter250, the source driver260, and the plurality of switches271to273, respectively, and may perform operations similar to those of the constituent elements in the first driver circuit.

The driver circuit included in the master panel may compare the first and second gamma reference voltages VG1and VG2. The driver circuit included in the slave panel may transfer its own gamma reference voltage to the driver circuit included in the master panel. For example, the first driver circuit200may be included in the master panel, and the second driver circuit300may be included in the slave panel. The second driver circuit300may transfer the second gamma reference voltage VG2to the first driver circuit200. The first driver circuit200may compare the first and second gamma reference voltages VG1and VG2.

The processor150may monitor the gamma reference voltages, and designate the master panel and the slave panel on the basis of the gamma reference voltages. Before the processor150designates the master panel and the slave panel, any one display panel may be designated as the master panel in advance. For example, of the first and second display panels, the first display panel may be designated as the master panel in advance, and the processor150may change the master panel on the basis of the gamma reference voltages of the first and second display panels.

In some implementations, the processor150may receive data on the difference between the first gamma reference voltage and the second gamma reference voltage (reference symbol “DF” inFIG.1) from the controller210of the display panel (for example, the display panel including the first driver circuit200). In some implementations, the processor150may receive the first gamma reference voltage from the controller210of the display panel (for example, the display panel including the first driver circuit200), receive the second gamma reference voltage from the controller310of the display panel (for example, the display panel including the second driver circuit300), and compare the first gamma reference voltage and the second gamma reference voltage. When the second gamma reference voltage is higher than the first gamma reference voltage, the processor150may designate the display panel including the second driver circuit300as the master panel, and designate the display panel including the first driver circuit200as the slave panel. In some implementations, the processor150may monitor the gamma reference voltages when power is applied to the display device50. In some implementations, the processor150may monitor the gamma reference voltages at regular monitoring intervals. For example, the processor150may monitor the gamma reference voltages during each vertical blanking period for a frame. In some implementations, the processor150may monitor the gamma reference voltages when an application or the like for generating image data IS to be provided to the display device50is changed. However, the period during which the processor150monitors the gamma reference voltages may be variously set, and is not limited to the above description.

In some implementations, the first and second driver circuits200and300may further include capacitors for stabilizing the first and second gamma reference voltages VG1and VG2output from the buffers240and340, respectively. For example, the first driver circuit200may include a first capacitor for stabilizing the first gamma reference voltage VG1. The second driver circuit300may include a second capacitor for stabilizing the second gamma reference voltage VG2. The first and second capacitors may remove noise components from the first and second gamma reference voltages VG1and VG2. In this case, the first and second capacitors may be disposed outside the first and second driver circuits200and300. In other words, one end of each of the first and second capacitors may be coupled to a ground, and the other ends of them may be coupled to pads coupled to the buffers240and340, respectively.

FIG.3is a circuit diagram for explaining the operation of the display device according to some implementations.

Referring toFIG.3, the display device50according to some implementations may operate in a general situation or a normal situation. In the first driver circuit200, the voltage generator220may generate a first gamma reference voltage VG1, and output it to the multiplexer230. The controller210may output a first-level selection signal muxsel1to the multiplexer230. The multiplexer230may select a first gamma reference voltage VG1based on the first-level selection signal muxsel1. The buffer240may output the first gamma reference voltage VG1. The source driver260may generate a plurality of gamma voltages on the basis of the first gamma reference voltage VG1. The source driver260may generate a first data signal on the basis of the plurality of gamma voltages, and output it to the first pixel array. The first pixel array may emit image light based on the first data signal from the source driver260.

In the second driver circuit300, the voltage generator320may generate a second gamma reference voltage VG2, and output it to the multiplexer330. The controller310may output a selection signal muxsel2at a first level to the multiplexer330. The multiplexer330may select a second gamma reference voltage VG2based on the first-level selection signal muxsel2. The buffer340may output the second gamma reference voltage VG2. The source driver360may generate a second data signal on the basis of the second gamma reference voltage VG2, and output it to the second pixel array. The second pixel array may emit image light based on the second data signal from the source driver360. The user can view the image light emitted from the first and second pixel arrays.

FIG.4is a circuit diagram for explaining the operation of the display device according to some implementations.

Referring toFIG.4, the display device50according to some implementations may monitor the first and second gamma reference voltages VG1and VG2in a general situation and a normal situation. For example, the first driver circuit200included in the master panel may perform monitoring.

For monitoring, the processor150may transmit an opening/closing instruction signal to the switches271,272, and373. The switches271,272, and373may be closed in response to an opening/closing instruction signal. In the first driver circuit200, the voltage generator220may generate a first gamma reference voltage VG1, and output it to the multiplexer230. The controller210may output a first-level selection signal muxsel1to the multiplexer230. The multiplexer230may select a first gamma reference voltage VG1based on the first-level selection signal muxsel1. The buffer240may output the first gamma reference voltage VG1. The first gamma reference voltage VG1may be input to the analog-to-digital converter250through the switch272.

In the second driver circuit300, the voltage generator320may generate a second gamma reference voltage VG2, and output it to the multiplexer330. The controller310may output a first-level selection signal muxsel2to the multiplexer330. The multiplexer330may select a second gamma reference voltage VG2based on the first-level selection signal muxsel2. The buffer340may output the second gamma reference voltage VG2. The second gamma reference voltage VG2may be input to the analog-to-digital converter250through the switch373and the switch271.

The analog-to-digital converter250may generate first and second sampling values by sampling the first and second gamma reference voltages VG1and VG2. The analog-to-digital converter250may output the first and second sampling values to the controller210. The controller210may determine the difference between the first and second gamma reference voltages VG1and VG2on the basis of the first and second sampling values.

It has been described with reference toFIG.4that the panel including the first driver circuit200is the master panel; however, implementations are not limited thereto, and the same description may also be applied to the case where the panel including the second driver circuit300is the master panel. In this case, the controller310may determine the difference between the first and second gamma reference voltages VG1and VG2.

FIG.5is a circuit diagram for explaining the operation of the display device according to some implementations.

Referring toFIG.5, the controller210according to some implementations may determine that the display device50is normally operating, when the first sampling value and the second sampling value are the same or the difference between the first and second sampling values is smaller than the first reference value. When the display device50is normally operating, the controller210may keep the current operation. In other words, the controller210may keep outputting the first-level selection signal muxsel1. The multiplexer230may select the first gamma reference voltage VG1in response to the first-level selection signal muxsel1, and output it. The first gamma reference voltage VG1may be input to the source driver260through the buffer240such that it is used to generate a first data signal.

Similarly, the controller310may keep the current operation to keep outputting the first-level selection signal muxsel2. Accordingly, the source driver360may keep generating a second data signal based on the second gamma reference voltage VG2. In this case, the switches271,272, and373may be closed in response to the opening/closing instruction signal from the processor150, and the analog-to-digital converter250may keep sampling the first and second gamma reference voltages VG1and VG2. The controller210may keep monitoring the first and second gamma reference voltages VG1and VG2on the basis of the first and second sampling values output from the analog-to-digital converter250.

FIG.6is a circuit diagram for explaining the operation of the display device according to some implementations.

Referring toFIG.6, the controller210according to some implementations may determine that the first sampling value is smaller than the second sampling value, on the basis of the first and second sampling values from the analog-to-digital converter250. When the difference between the first and second sampling values is in a range equal to or greater than the first reference value and smaller than the second reference value (wherein the second reference value is greater than the first reference value), the controller210may output a control signal CT1on the basis of the difference, and output the first-level selection signal muxsel1. The voltage generator220may amplify the first gamma reference voltage VG1on the basis of the control signal CT1. The control signal CT1may contain information on a degree of amplification. The multiplexer230may select the amplified first gamma reference voltage VG1on the basis of the first-level selection signal muxsel1, and output it. The magnitude of the amplified first gamma reference voltage VG1may be substantially the same as that of the second gamma reference voltage VG2.

In the second driver circuit300, the controller310may keep the current operation to keep outputting the first-level selection signal muxsel2. Accordingly, the source driver360may keep generating a second data signal based on the second gamma reference voltage VG2. The first and second driver circuits200and300may generate data signals on the basis of gamma reference voltages having substantially the same magnitude, such that the user can view high-quality images.

In some implementations, the controller210may transmit information that the first gamma reference voltage VG1is less than the second gamma reference voltage VG2, to the processor150. Accordingly, the processor150may set the panel including the second driver circuit300as the master panel, and the controller310may monitor the first and second gamma reference voltages VG1and VG2on the basis of the sampling values which are output from the analog-to-digital converter350. In this case, the processor150may close the switches273,371, and372, and open the switches271,272, and373.

FIG.7is a circuit diagram for explaining the operation of the display device according to some implementations.

Referring toFIG.7, the controller210according to some implementations may determine that the second sampling value is smaller than the first sampling value, on the basis of the first and second sampling values from the analog-to-digital converter250. When the difference between the first and second sampling values is in a range equal to or greater than the first reference value and smaller than the second reference value (wherein the second reference value is greater than the first reference value), the controller210may transmit first difference data to the processor150. The processor150may transmit an amplification insulation signal corresponding to the first difference data, to the controller310of the second driver circuit300. The controller310may output a control signal CT2on the basis of the amplification instruction signal, and output the first-level selection signal muxsel2. The voltage generator320may amplify the second gamma reference voltage VG2on the basis of the control signal CT2. The control signal CT2may contain information on a degree of amplification. The multiplexer330may select the amplified second gamma reference voltage VG2, on the basis of the first-level selection signal muxsel2. The buffer340may transfer the amplified second gamma reference voltage VG2to the source driver360. The source driver360may generate a data signal based on the amplified second gamma reference voltage VG2. The magnitude of the amplified second gamma reference voltage VG2may be substantially the same as that of the first gamma reference voltage VG1.

In the first driver circuit200, the controller210may output the first-level selection signal muxsel1to the multiplexer230. The multiplexer230may select the first gamma reference voltage VG1on the basis of the first-level selection signal muxsel1and output it. The first and second driver circuits200and300may generate data signals on the basis of gamma reference voltages having substantially the same magnitude, such that the user can view high-quality images.

FIG.8andFIG.9are circuit diagrams for explaining the operation of the display device according to some implementations.

Referring toFIG.8, the controller210according to some implementations may determine that the second sampling value is smaller than the first sampling value, on the basis of the first and second sampling values from the analog-to-digital converter250. When the difference between the first and second sampling values is equal to or greater than the second reference value, the controller210may transmit second difference data corresponding to the difference, to the processor150. The processor150may perform control based on the second difference data such that the first and second driver circuits200and300share a gamma reference voltage. For example, the processor150may transfer the first gamma reference voltage VG1to the second driver circuit300.

Referring toFIG.9, the processor150according to some implementations may receive the second difference data from the controller210. The processor150may generate an opening/closing instruction signal for opening or closing a plurality of switches271to273and371to373, on the basis of the second difference data. For example, the processor150may transmit the opening/closing instruction signal to the switches273and371, thereby closing the switches273and371. The switches271,272,372, and373that have not received the opening/closing instruction signal (or have received the opening/closing instruction signal at the low level) may be left open.

The voltage generator220may keep generating the first gamma reference voltage VG1, and the controller210may output the first-level selection signal muxsel1. The multiplexer230may transfer the first gamma reference voltage VG1to the buffer240on the basis of the first-level selection signal muxsel1. Since the switch271is open, the multiplexer230may not receive the second gamma reference voltage VG2. The first gamma reference voltage VG1passing through the buffer240may be transferred to the second driver circuit300through the switch273.

In the second driver circuit300, the first gamma reference voltage VG1may be transferred to the multiplexer330through the switch371.

The processor150may transmit a selection instruction signal to the controller310of the second driver circuit300. The controller310may output the selection signal muxsel2at a second level, on the basis of the selection instruction signal. In some implementations, the controller310may instruct the voltage generator320not to generate the second gamma reference voltage VG2.

The multiplexer330may select the first gamma reference voltage VG1on the basis of the second-level selection signal muxsel2. The first gamma reference voltage VG1output from the multiplexer330may be provided to the source driver360through the buffer340. The source driver360may generate a second data signal based on the first gamma reference voltage VG1. As described above, both of the source driver260of the first driver circuit200and the source driver360of the second driver circuit300may generate data signals based on the first gamma reference voltage VG1. In other words, the display device50may perform control such that the first and second driver circuits200and300use the same gamma reference voltage even when a difference occurs between the first gamma reference voltage VG1and the second gamma reference voltage VG2, thereby providing high-quality images to the user and improving the user's experience in artificial reality.

FIG.10is a circuit diagram for explaining the operation of a display device according to some implementations.

Referring toFIG.10, a display device70according to some implementations includes a first driver circuit500that generates a first data signal and a second driver circuit600that generates a second data signal. The display device70may emit image light under the control of a processor700.

The first driver circuit500may be included in a master panel, and the second driver circuit600may be included in a slave panel. The first driver circuit500which is included in the master panel may compare gamma voltages. For example, a first minimum gamma voltage generator501includes an analog-to-digital converter515, which may receive a first minimum gamma voltage VG_BOT1and a second minimum gamma voltage VG_BOT2. A first maximum gamma voltage generator502includes an analog-to-digital converter535, which may receive a first maximum gamma voltage VG_TOP1and a second maximum gamma voltage VG_TOP2. Controllers511and531may compare sampling values of the analog-to-digital converters515and535, and operate according to the comparison result. For example, the controllers511and531may operate to minimize the difference between sampling values.

The processor700may change the master panel and the slave panel while the display device70is displaying images. For example, the processor700may compare gamma voltages output from the first and second driver circuits500and600(for example, the first and second minimum gamma voltages VG_BOT1and VG_BOT2, and the first and second maximum gamma voltages VG_TOP1and VG_TOP2), and designate a panel having a higher gamma voltage as the master panel, and designate a panel having a lower gamma voltage as the slave panel.

The first driver circuit500includes the first minimum gamma voltage generator501, the first maximum gamma voltage generator502, and a source driver550. The first minimum gamma voltage generator501may generate a first minimum gamma voltage VG_BOT1. The first minimum gamma voltage generator501may output the first minimum gamma voltage VG_BOT1to at least one of the source driver550and a second minimum gamma voltage generator601. For example, in a normal situation, the first minimum gamma voltage generator501may output the first minimum gamma voltage VG_BOT1to the source driver550. In an abnormal situation, the first minimum gamma voltage generator501may output the first minimum gamma voltage VG_BOT1to the source driver550and the second minimum gamma voltage generator601, in response to an instruction from the processor700.

The first minimum gamma voltage generator501includes the controller (BCTRL)511, a voltage generator (VBGEN)512, a multiplexer513, a buffer514, the analog-to-digital converter515, and a plurality of switches521to523. The contents related to the controller210, the voltage generator220, the multiplexer230, the buffer240, the analog-to-digital converter250, and the plurality of switches271to273described with reference toFIG.2may be applied similarly to the controller511, the voltage generator512, the multiplexer513, the buffer514, the analog-to-digital converter515, and the plurality of switches521to523. Accordingly, a redundant description will not be made.

The first maximum gamma voltage generator502may generate a first maximum gamma voltage VG_TOP1. The first maximum gamma voltage VG_TOP1may be higher than the first minimum gamma voltage VG_BOT1. The first maximum gamma voltage generator502includes the controller (TCTRL)531, a voltage generator (VTGEN)532, a multiplexer533, a buffer534, the analog-to-digital converter535, and a plurality of switches541to543. The contents related to the controller210, the voltage generator220, the multiplexer230, the buffer240, the analog-to-digital converter250, and the plurality of switches271to273described with reference toFIG.2may be applied similarly to the controller (TCTRL)531, the voltage generator (VTGEN)532, the multiplexer533, the buffer534, the analog-to-digital converter535, and the plurality of switches541to543. Accordingly, a redundant description will not be made.

In a normal situation, the source driver550may generate a first data signal on the basis of the first minimum gamma voltage VG_BOT1and the first maximum gamma voltage VG_TOP1. For example, the source driver550may include a gamma voltage generator which generates a plurality of gamma voltages on the basis of the first minimum gamma voltage VG_BOT1and the first maximum gamma voltage VG_TOP1. The gamma voltage generator may include a resistor string, of whose both ends may receive the first minimum gamma voltage VG_BOT1and the first maximum gamma voltage VG_TOP1. In a normal situation, the source driver550may generate a first data signal based on the plurality of gamma voltages.

In an abnormal situation, the source driver550may receive at least one of the second maximum gamma voltage VG_TOP2and the second minimum gamma voltage VG_BOT2from the second driver circuit600. An abnormal situation may be understood as a situation in which the difference between gamma voltages is large. For example, the first minimum gamma voltage VG_BOT1may need to be equal to or similar to the second minimum gamma voltage VG_BOT2, and the first maximum gamma voltage VG_TOP1may need to be equal to or similar to the second maximum gamma voltage VG_TOP2. The case where such voltages are not equal to each other and the difference therebetween is large may be referred to as an abnormal situation.

When the first minimum gamma voltage VG_BOT1is abnormal, the source driver550may receive the second minimum gamma voltage VG_BOT2from the second driver circuit600. When the first maximum gamma voltage VG_TOP1is abnormal, the source driver550may receive the second maximum gamma voltage VG_TOP2from the second driver circuit600. When the first minimum gamma voltage VG_BOT1and the first maximum gamma voltage VG_TOP1are abnormal, the source driver550may receive the second minimum gamma voltage VG_BOT2and the second maximum gamma voltage VG_TOP2from the second driver circuit600. In an abnormal situation, the processor700may change the electrical wiring of the first and second driver circuits500and600by opening or closing a plurality of switches521to523,541to543,621to623, and641to643. In an abnormal situation, the source driver550may generate a plurality of gamma voltages based on any one of the first minimum gamma voltage VG_BOT1and the second minimum gamma voltage VG_BOT2and any one of the first maximum gamma voltage VG_TOP1and the second maximum gamma voltage VG_TOP2, and generate a first data signal based on the plurality of gamma voltages.

In some implementations, the controllers511and531may be integrated and operate as a single controller.

The second driver circuit600includes a sixth minimum gamma voltage generator601, a second maximum gamma voltage generator602, and a source driver650. The sixth minimum gamma voltage generator601, the second maximum gamma voltage generator602, and the source driver650may be substantially similar to the first minimum gamma voltage generator501, the first maximum gamma voltage generator502, and the source driver550, respectively in the first driver circuit500. Accordingly, a redundant description will not be made.

In some implementations, each of the first and second driver circuits500and600may further include capacitors for stabilizing the gamma voltages VG_BOT1, VG_TOP1, VG_BOT2, and VG_TOP2which are output from buffers514,534,614, and634. For example, the first driver circuit500may include a first capacitor for stabilizing the first minimum gamma voltage VG_BOT1and a second capacitor for stabilizing the first maximum gamma voltage VG_TOP1. The second driver circuit600may include a third capacitor for stabilizing the second minimum gamma voltage VG_BOT2and a fourth capacitor for stabilizing the second maximum gamma voltage VG_TOP2. The first to fourth capacitors may remove noise components from the gamma voltages VG_BOT1, VG_TOP1, VG_BOT2, and VG_TOP2. In this case, the first to fourth capacitors may be disposed outside the first and second driver circuits500and600. In other words, one end of each of the first to fourth capacitors may be coupled to a ground, and the other ends of them may be coupled to pads coupled to the buffers514,534,614, and634.

FIG.11is a block diagram for explaining the operation of a display device according to some implementations.

Referring toFIG.11, a display device1000according to some implementations includes a first display panel1100and a second display panel1200. The display device1000may emit image light under the control of a processor1300.

The processor1300may control the overall operation of the display device1000. The processor1300may perform control such that the display device1000emits first image light to one eye of a user and emits second image light to the other eye of the user. The processor1300may transmit first image data to the first display panel1100and transmit second image data to the second display panel1200. In some implementations, the first image data and the second image data may be the same, or may be different. The first display panel1100may emit first image light based on the first image data, and the second display panel1200may emit second image light based on the second image data.

The processor1300may set the first display panel1100as the master panel, and set the second display panel1200as the slave panel. The master panel may receive a sampling value corresponding to the gamma voltage of the slave panel, from the slave panel, and compare a sampling value corresponding to its own gamma voltage with the sampling value of the slave panel. The master panel may operate to minimize the difference between the gamma voltages. The processor1300may monitor the gamma voltages (or sampling values) of the first and second display panels1100and1200while the display device1000is displaying images. When the gamma voltage of the first display panel1100gets lower than the gamma voltage of the second display panel1200, the processor1300may set the second display panel1200as the master panel and set the first display panel1100as the slave panel.

The first display panel1100includes a display driver circuit (DDIC)1110, a pixel array1120, and an analog-to-digital converter (ADC)1130. The display driver circuit1110may generate a first data signal, using a first gamma reference voltage, on the basis of the first image data received from the processor1300.

The display driver circuit1110may transmit the first data signal to the pixel array1120through source lines SL. The pixel array1120may emit first image light based on the first data signal. The source lines SL may couple the display driver circuit1110, the pixel array1120, and the analog-to-digital converter1130. In other words, the first data signal output from the display driver circuit1110may be used in the pixel array1120to emit first image light, and be input to the analog-to-digital converter1130. The analog-to-digital converter1130may generate a first sampling value by sampling the input first data signal. The analog-to-digital converter1130may transmit the first sampling value to the display driver circuit1110.

The second display panel1200includes a display driver circuit (DDIC)1210, a pixel array1220, and an analog-to-digital converter (ADC)1230. As in the first display panel1100, the display driver circuit1210may generate a second data signal, using a second gamma reference voltage, on the basis of the second image data, and transmit the second data signal to the pixel array1220and the analog-to-digital converter1230through the source lines SL. The analog-to-digital converter1230may generate a second sampling value by sampling the second data signal, and transmit the second sampling value to the display driver circuit1210.

The processor1300may transmit the second sampling value of the second display panel1200which is the slave panel, to the display driver circuit1110of the first display panel1100. For example, the processor1300may change electrical wiring by controlling opening and closing of switches of the display driver circuit1210.

The display driver circuit1110of the first display panel1100may compare the first sampling value and the second sampling value. The display driver circuit1110may determine the difference between the first sampling value and the second sampling value. When the difference is smaller than a first reference value, the display driver circuit1110may keep the current operation. In other words, the display driver circuit1110may keep generating the first data signal using the first gamma reference voltage, and the pixel array1120may keep emitting first image light based on the first data signal. Similarly, the display driver circuit1210may keep generating the second data signal using the second gamma reference voltage, and the pixel array1220may keep emitting second image light based on the second data signal.

When the first sampling value is smaller than the second sampling value and the difference is equal to or greater than the first reference value and is smaller than a second reference value, the display driver circuit1110may amplify the first gamma reference voltage. The display driver circuit1110may generate a first data signal using the amplified first gamma reference voltage, and the pixel array1120may emit first image light based on the first data signal.

When the first sampling value is greater than the second sampling value and the difference is equal to or greater than the first reference value and is smaller than the second reference value, the display driver circuit1110may transmit the difference to the processor1300. The processor1300may instruct the display driver circuit1210to amplify the second gamma reference voltage on the basis of the difference. The display driver circuit1210may generate a second data signal using the amplified second gamma reference voltage, and the pixel array1220may emit second image light based on the second data signal. In some implementations, the display driver circuit1110may transmit the difference to the display driver circuit1210, and the display driver circuit1210may amplify the second gamma reference voltage on the basis of the difference.

When the second sampling value is greater than the first sampling value, and the difference is equal to or greater than the second reference value and is smaller than a third reference value, the display driver circuit1110may transmit the difference to the processor1300. On the basis of the difference, the processor1300may instruct the display driver circuit1210to transfer the second gamma reference voltage to the display driver circuit1110, and instruct the display driver circuit1110to use the second gamma reference voltage instead of the first gamma reference voltage. For example, the processor1300may control opening and closing of the switches of the display driver circuits1110and1210to transfer the second gamma reference voltage to the display driver circuit1110. The processor1300may perform control such that the multiplexer of the display driver circuit1110selects the second gamma reference voltage instead of the first gamma reference voltage.

When the first sampling value is greater than the second sampling value, and the difference is equal to or greater than the second reference value and is smaller than the third reference value, the display driver circuit1110may transmit the difference to the processor1300. On the basis of the difference, the processor1300may instruct the display driver circuit1110to transfer the first gamma reference voltage to the display driver circuit1210, and instruct the display driver circuit1210to use the first gamma reference voltage instead of the second gamma reference voltage. For example, the processor1300may control opening and closing of the switches of the display driver circuits1110and1210to transfer the first gamma reference voltage to the display driver circuit1210. The processor1300may perform control such that the multiplexer of the display driver circuit1210selects the first gamma reference voltage instead of the second gamma reference voltage.

As described above, the first and second display panels1100and1200may generate the same gamma reference voltage and output data signals having the same level, whereby the display device1000may output images having the same luminance level corresponding to the same gray level to both eyes of a user, such that the user can view the images with high quality.

FIG.12is a block diagram for explaining the operation of a display device according to some implementations.

Referring toFIG.12, a display device2000according to some implementations includes a first display panel2100and a second display panel2200. The display device2000may emit image light under the control of a processor2300.

The processor2300may control the overall operation of the display device2000. The processor2300may perform control such that the display device2000emits first image light to one eye of a user and emits second image light to the other eye of the user. The processor2300may transmit first image data to the first display panel2100and transmit second image data to the second display panel2200. In some implementations, the first image data and the second image data may be the same, or may be different. The first display panel2100may emit first image light based on the first image data, and the second display panel2200may emit second image light based on the second image data.

The processor2300may set the first display panel2100as the master panel, and set the second display panel2200as the slave panel. The master panel may receive a sampling value corresponding to the gamma voltage of the slave panel, from the slave panel, and compare a sampling value corresponding to its own gamma voltage with the sampling value of the slave panel. The master panel may operate to minimize the difference between the gamma voltages. The processor2300may monitor the gamma voltages (or sampling values) of the first and second display panels2100and2200while the display device2000is displaying images. When the gamma voltage of the first display panel2100gets lower than the gamma voltage of the second display panel2200, the processor2300may set the second display panel2200as the master panel and set the first display panel2100as the slave panel.

The first display panel2100includes a display driver circuit (DDIC)2110, a pixel array2120, and an analog-to-digital converter (ADC)2130. The display driver circuit2110may generate a first data signal and a dummy signal, using a first gamma reference voltage, on the basis of the first image data received from the processor2300.

The display driver circuit2110may transmit the first data signal and the dummy signal to the pixel array2120through source lines. The pixel array2120includes a first pixel array (ARRAY1)2121and a second pixel array2122. The first pixel array2121may emit first image light based on the first data signal. The second pixel array2122may be a dummy pixel array. For example, the second pixel array2122may emit black-level light based on the dummy signal. In some implementations, the second pixel array2122may be disposed at the edge of the first display panel2100, or may be covered with a packaging element (for example, a bezel, etc.) from the user.

The source lines includes first source lines SL1and second source lines SL2, and couple the display driver circuit2110, the pixel array2120, and the analog-to-digital converter2130. The first pixel array2121may receive the first data signal through the first source lines SL1. The second pixel array2122may receive the dummy signal through the second source lines SL2. In other words, the first data signal output from the display driver circuit2110may be used in the first pixel array2121to emit first image light, and be input to the analog-to-digital converter2130. The dummy signal output from the display driver circuit2110may be used in the second pixel array2122to emit black-level light, and be input to the analog-to-digital converter2130.

The analog-to-digital converter2130may generate a first sampling value by sampling at least one of the first data signal and the dummy signal input thereto. In some implementations, the analog-to-digital converter2130may generate a first sampling value by sampling the dummy signal. The analog-to-digital converter2130may sample the dummy signal, thereby performing sampling in real time while the first pixel array2121is emitting the first image light. The analog-to-digital converter2130may transmit the first sampling value to the display driver circuit2110.

The second display panel2200includes a display driver circuit (DDIC)2210, a pixel array2220, and an analog-to-digital converter (ADC)2230. As in the first display panel2100, the display driver circuit2210may generate a second data signal and a dummy signal, using a second gamma reference voltage, on the basis of the second image data, and transmit the second data signal to the pixel array2220and the analog-to-digital converter2230through first source lines SL1, and transmit the dummy signal to the pixel array2220and the analog-to-digital converter2230through second source lines SL2. The analog-to-digital converter2230may generate a second sampling value by sampling at least one of the second data signal and the dummy signal, and transmit the second sampling value to the display driver circuit2210.

The processor2300may transmit the second sampling value of the second display panel2200which is the slave panel, to the display driver circuit2110of the first display panel2100. For example, the processor2300may change electrical wiring by controlling opening and closing of switches of the display driver circuit2210.

The display driver circuit2110of the first display panel2100may compare the first sampling value and the second sampling value. The display driver circuit2110may determine the difference between the first sampling value and the second sampling value. When the difference is smaller than a first reference value, the display driver circuit2110may keep the current operation. In other words, the display driver circuit2110may keep generating the first data signal and the dummy signal using the first gamma reference voltage, and the first pixel array2121may keep emitting first image light based on the first data signal. Similarly, the display driver circuit2210may keep generating the second data signal and the dummy signal using the second gamma reference voltage, and the second pixel array2122may keep emitting second image light based on the second data signal.

When the first sampling value is smaller than the second sampling value and the difference is equal to or greater than the first reference value and is smaller than a second reference value, the display driver circuit2110may amplify the first gamma reference voltage. The display driver circuit2110may generate a first data signal and a dummy signal using the amplified first gamma reference voltage, and the first pixel array2121may emit first image light based on the first data signal.

When the first sampling value is greater than the second sampling value and the difference is equal to or greater than the first reference value and is smaller than the second reference value, the display driver circuit2110may transmit the difference to the processor2300. The processor2300may instruct the display driver circuit2210to amplify the second gamma reference voltage on the basis of the difference. The display driver circuit2210may generate a second data signal and a dummy signal using the amplified second gamma reference voltage, and the second pixel array2122may emit second image light based on the second data signal. In some implementations, the display driver circuit2120may transmit the difference to the display driver circuit2210, and the display driver circuit2210may amplify the second gamma reference voltage on the basis of the difference.

When the second sampling value is greater than the first sampling value, and the difference is equal to or greater than the second reference value and is smaller than a third reference value, the display driver circuit2110may transmit the difference to the processor2300. On the basis of the difference, the processor2300may instruct the display driver circuit2210to transfer the second gamma reference voltage to the display driver circuit2110, and instruct the display driver circuit2110to use the second gamma reference voltage instead of the first gamma reference voltage. For example, the processor2300may control opening and closing of the switches of the display driver circuits2110and2210to transfer the second gamma reference voltage to the display driver circuit2110. The processor2300may perform control such that the multiplexer of the display driver circuit2110selects the second gamma reference voltage instead of the first gamma reference voltage.

When the first sampling value is greater than the second sampling value, and the difference is equal to or greater than the second reference value and is smaller than the third reference value, the display driver circuit2110may transmit the difference to the processor2300. On the basis of the difference, the processor2300may instruct the display driver circuit2110to transfer the first gamma reference voltage to the display driver circuit2210, and instruct the display driver circuit2210to use the first gamma reference voltage instead of the second gamma reference voltage. For example, the processor2300may control opening and closing of the switches of the display driver circuits2110and2210to transfer the first gamma reference voltage to the display driver circuit2210. The processor2300may perform control such that the multiplexer of the display driver circuit2210selects the first gamma reference voltage instead of the second gamma reference voltage.

As described above, the first and second display panels2100and2200may generate the same gamma reference voltage and output data signals having the same level, whereby the display device2000may output images having the same luminance level corresponding to the same gray level to both eyes of a user, such that the user can view the images with high quality.

FIG.13is a flow chart of an image display method according to some implementations.

Referring toFIG.13, a display device according to some implementations may include first and second display panels that emit first and second image light, respectively. The first display panel may emit first image light based on a first gamma reference voltage VG1, and the second display panel may emit second image light based on a second gamma reference voltage VG2. The first display panel may perform an image display method.

The first display panel may compare the first gamma reference voltage VG1and the second gamma reference voltage VG2(S1310). The first display panel may determine the voltage difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2. For example, the first display panel may obtain first and second sampling values by sampling the first gamma reference voltage VG1and the second gamma reference voltage VG2by an analog-to-digital converter, and compare the first and second sampling values. The first display panel may determine the difference between the first and second sampling values, as the voltage difference.

When the first gamma reference voltage VG1is less than the second gamma reference voltage VG2, the first display panel may change the first gamma reference voltage VG1(S1320). When the first sampling value is smaller than the second sampling value, the first display panel may determine that the first gamma reference voltage VG1is less than the second gamma reference voltage VG2.

In some implementations, when the first gamma reference voltage VG1is less than the second gamma reference voltage VG2, and the voltage difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2is equal to or greater than a first reference value and is smaller than a second reference value, the first display panel may amplify the first gamma reference voltage VG1. Here, the second reference value may be greater than the first reference value. The voltage difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2may correspond to the difference between the first sampling value and the second sampling value. Further, when the first gamma reference voltage VG1is less than the second gamma reference voltage VG2, and the voltage difference is equal to or greater than the second reference value, the first display panel may use the second gamma reference voltage VG2, instead of the first gamma reference voltage VG1, to emit first image light.

When the second gamma reference voltage VG2is less than the first gamma reference voltage VG1, the first display panel may instruct the second display panel to change the second gamma reference voltage VG2(S1330). When the second sampling value is smaller than the first sampling value, the first display panel may determine that the second gamma reference voltage VG2is less than the first gamma reference voltage VG1.

In some implementations, when the second gamma reference voltage VG2is less than the first gamma reference voltage VG1, and the voltage difference between the first gamma reference voltage VG1and the second gamma reference voltage VG2is equal to or greater than the first reference value and is smaller than the second reference value, the first display panel may output a first signal to instruct the second display panel to amplify the second gamma reference voltage VG2.

Further, when the second gamma reference voltage VG2is less than the first gamma reference voltage VG1, and the voltage difference is equal to or greater than the second reference value, the first display panel may output a second signal to instruct the second display panel to use the first gamma reference voltage VG1instead of the second gamma reference voltage VG2.

In some implementations, the first display panel may transmit at least one of the first signal and the second signal to the second display panel. In some implementations, the first display panel may transmit at least one of the first signal and the second signal to a processor that manages the first display panel and the second display panel. The processor may control the second display panel on the basis of at least one of the first signal and the second signal. The second display panel may amplify the second gamma reference voltage VG2or may use the first gamma reference voltage VG1, on the basis of at least one of the first signal and the second signal or under the control of the processor.

As described above, the first and second display panels of the display device emit image light using gamma reference voltages having the same magnitude, such that a user using the display device can view images having the same quality. Therefore, the user's experience can be improved.

In some implementations, each of the components described with reference toFIG.1toFIG.13, or a combination of two or more components may be implemented as a digital circuit, a programmable or non-programmable logic device or array, an application specific integrated circuit (ASIC), etc.