Projection device, illumination device thereof and light source driving method

Abstract

The present application provides a projection device, an illumination device and a light source driving method. A control module converts a bit control signal into a plurality of first light source timing signals, converts the plurality of first light source timing signals into a plurality of second light source timing signals according to a look-up table, generates driving currents corresponding to each light source according to the look-up table, outputs a plurality of first light source driving signals corresponding to the plurality of light sources according to the plurality of first light source timing signals, and outputs a plurality of second light source driving signals corresponding to the plurality of light sources according to the plurality of second light source timing signals, wherein the look-up table includes driving current ratios corresponding to the plurality of light sources. A driving module drives the plurality of light sources according to the plurality of first light source driving signals and the driving currents to make the plurality of light sources have non-overlapping light emission timing. The driving module drives the plurality of light sources according to the plurality of second light source driving signals and the driving currents to make the plurality of light sources have overlapping light emission timing.

Description

Technical Field

[0001] This invention relates to a display device, and more particularly to a projection device, its lighting device, and a method for driving the light source. Background Technology

[0002] Existing projection device architectures control light source emission in a non-overlapping emission sequence. For example, in a projection device's illumination module that includes red, green, and blue light sources, only one color of light source can emit light at a time. Therefore, this emission mode often fails to meet the brightness and color gamut requirements of modern projection devices. Summary of the Invention

[0003] The present invention provides a projection device, a lighting device and a light source driving method thereof, which can control the light emission of the light source by overlapping the emission timing, thereby meeting the projection device's requirements for brightness and color gamut.

[0004] The lighting device of the present invention includes a light source module, a processing module, a control module, and a driving module. The light source module includes multiple light sources. The processing module generates bit control signals based on image signals. The control module, coupled to the processing module, converts the bit control signals into multiple first light source timing signals, converts the multiple first light source timing signals into multiple second light source timing signals according to a lookup table, generates driving currents corresponding to each light source according to the lookup table, outputs multiple first light source driving signals corresponding to the multiple light sources based on the multiple first light source timing signals, and outputs multiple second light source driving signals corresponding to the multiple light sources based on the multiple second light source timing signals, wherein the lookup table includes the driving current ratios corresponding to the multiple light sources. The driving module, coupled to the control module and the light source module, drives the multiple light sources according to the multiple first light source driving signals and driving currents to ensure that the multiple light sources have non-overlapping emission timings. It also drives the multiple light sources according to the multiple second light source driving signals and driving currents to ensure that the multiple light sources have overlapping emission timings.

[0005] The present invention also provides a projection device, comprising an illumination device, a light valve, and a projection lens. The illumination device includes a light source module, a processing module, a control module, and a driving module. The light source module includes multiple light sources for providing an illumination beam. The processing module generates bit control signals based on an image signal. The control module, coupled to the processing module, converts the bit control signals into multiple first light source timing signals, converts the multiple first light source timing signals into multiple second light source timing signals according to a lookup table, generates driving currents corresponding to each light source according to the lookup table, outputs multiple first light source driving signals corresponding to the multiple light sources based on the multiple first light source timing signals, and outputs multiple second light source driving signals corresponding to the multiple light sources based on the multiple second light source timing signals, wherein the lookup table includes the driving current ratios corresponding to the multiple light sources. The driving module, coupled to the control module and the light source module, drives the multiple light sources according to the multiple first light source driving signals and driving currents to ensure that the multiple light sources have non-overlapping emission timings. It also drives the multiple light sources according to the multiple second light source driving signals and driving currents to ensure that the multiple light sources have overlapping emission timings. The light valve is located on the transmission path of the illumination beam and converts the illumination beam into an image beam. The projection lens is located in the path of the image beam and projects the image beam out of the projection device.

[0006] The present invention also provides a light source driving method for a lighting device, the lighting device including multiple light sources, the light source driving method comprising the following steps: A processing module generates a bit control signal based on an image signal. A control module converts the bit control signal into multiple first light source timing signals, converts the multiple first light source timing signals into multiple second light source timing signals according to a lookup table, generates a driving current corresponding to each light source according to the lookup table, outputs multiple first light source driving signals corresponding to the multiple light sources according to the multiple first light source timing signals, and outputs multiple second light source driving signals corresponding to the multiple light sources according to the multiple second light source timing signals, wherein the lookup table includes the driving current ratios corresponding to the multiple light sources. A driving module drives the multiple light sources according to the multiple first light source driving signals and driving currents to enable the multiple light sources to have non-overlapping emission timing sequences, and drives the multiple light sources according to the multiple second light source driving signals and driving currents to enable the multiple light sources to have overlapping emission timing sequences.

[0007] Based on the above, the control module of this embodiment can convert the bit control signal into multiple first light source timing signals, convert the multiple first light source timing signals into multiple second light source timing signals according to a lookup table, generate the corresponding driving current for each light source according to the lookup table, and generate the corresponding multiple second light source driving signals according to the multiple second light source timing signals. The driving module can drive the multiple light sources according to the multiple second light source driving signals and the corresponding driving currents, so that the multiple light sources have overlapping emission timing, thereby improving the brightness of the projected image of the projection device and meeting the color gamut requirements of the projection device.

[0008] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a lighting device according to an embodiment of the present invention.

[0010] Figure 2 This is a schematic diagram of a projection device according to an embodiment of the present invention.

[0011] Figure 3 This is a waveform diagram of the timing signal of the first light source according to an embodiment of the present invention.

[0012] Figure 4 This is a waveform diagram of the timing signal of the second light source according to an embodiment of the present invention.

[0013] Figure 5 This is a waveform diagram of the driving current according to an embodiment of the present invention.

[0014] Figure 6 This is a schematic diagram of a driving light source module according to an embodiment of the present invention.

[0015] Figure 7 This is a flowchart of a light source driving method for a lighting device according to an embodiment of the present invention. Detailed Implementation

[0016] To make the content of this invention more readily apparent, the following specific embodiments are provided as examples on which this invention can indeed be implemented. Furthermore, wherever possible, components / members referred to by the same reference numerals in the drawings and embodiments represent the same or similar parts.

[0017] Figure 1 This is a schematic diagram of a lighting device according to an embodiment of the present invention. Please refer to... Figure 1 The lighting device may include a light source module 102, a processing module 104, a control module 106, and a drive module 108. The control module 106 is coupled to the processing module 104 and the drive module 108, and the drive module 108 is also coupled to the light source module 102. The lighting device may be applied, for example, to a projection device, such as... Figure 2 As shown, the projection device may include a light valve 202 and a projection lens 204 in addition to the illumination device. The light valve 202 is located on the transmission path of the illumination beam L1 provided by the light source module 102 of the illumination device, and can convert the illumination beam L1 into an image beam L2. The projection lens 204 is located on the transmission path of the image beam L2, and can project the image beam L2 out of the projection device. Furthermore, in Figure 2In this embodiment, the control module 106 may include a control circuit 206, a logic circuit 208, and a logic circuit 210, wherein the logic circuit 208 is coupled to the processing module 104 and the control circuit 206, and the logic circuit 210 is coupled to the control circuit 206 and the drive module 108.

[0018] The driving module 108 is, for example, a light source driving circuit or other components and circuits with driving functions.

[0019] Processing module 104, control module 106, logic circuit 208, and logic circuit 210 are, for example, central processing unit (CPU), or other programmable general-purpose or special-purpose microcontroller (MCU), microprocessor, digital signal processor (DSP), programmable controller, application-specific integrated circuit (ASIC), graphics processing unit (GPU), image signal processor (ISP), image processing unit (IPU), arithmetic logic unit (ALU), complex programmable logic device (CPLD), field-programmable gate array (FPGA), or other similar elements or combinations thereof.

[0020] The light valve 202 can be a reflective light modulator, such as a liquid crystal on silicon panel (LCoS panel) or a digital micromirror device (DMD). In some embodiments, the light valve 202 can also be a transmissive light modulator, such as a transparent liquid crystal panel, an electro-optic modulator, a magneto-optic modulator, or an acousto-optic modulator (AOM). This invention does not limit the type or form of the light valve 202.

[0021] The projection lens 204 may include, for example, a combination of one or more optical lenses with refractive power, such as various combinations of non-planar lenses including biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. In one embodiment, the projection lens 204 may also include a planar optical lens to reflect the image beam L2 from the light valve 202 onto the projection target. The present invention does not limit the type or form of the projection lens 204.

[0022] The light source module 102 may include multiple light sources (not shown), such as multiple light-emitting diodes (LEDs), but is not limited thereto. The processing module 104 may generate bit control signals based on the image signal, such as generating two-bit bit control signals, which may be used, for example, to control the emission state of the red, green, and blue light sources included in the light source module 102, such as controlling the red, green, and blue light sources to be turned off simultaneously or to emit light independently, but is not limited thereto.

[0023] The control module 106 can convert the bit control signal into multiple first light source timing signals. For example, it can use a truth table design in the logic circuit to convert the multiple first light source timing signals into multiple second light source timing signals according to the lookup table, and generate multiple corresponding first light source driving signals or multiple second light source driving signals for the driving module 108 based on the multiple first light source timing signals and multiple second light source timing signals. Furthermore, the logic circuit 208 can convert the bit control signal into multiple first light source timing signals, and the control circuit 206 can convert the multiple first light source timing signals into multiple second light source timing signals according to the lookup table.

[0024] The first light source timing signal is used to instruct the multiple light sources of the light source module 102 to emit light in a manner where the light emission timing does not overlap. For example, such as Figure 3 As shown, the first light source timing signals SR1, SG1, and SB1 can be used to control the emission states of red, green, and blue light sources, respectively. When the first light source timing signal SR1, SG1, or SB1 is at a high logic level, the corresponding red, green, or blue light source is in an emission state; conversely, when the first light source timing signal SR1, SG1, or SB1 is at a low logic level, the corresponding red, green, or blue light source is in an off-light state. The second light source timing signal is used to instruct the multiple light sources of the light source module 102 to emit light in an overlapping emission timing manner, for example... Figure 4As shown, the second light source timing signals SR2, SG2, and SB2 can be used to control the emission states of red, green, and blue light sources, respectively. When the second light source timing signals SR2, SG2, or SB2 are at a high logic level, the corresponding red, green, or blue light source is in an emission state; when the second light source timing signals SR2, SG2, or SB2 are at a low logic level, the corresponding red, green, or blue light source is in an off-state. For example, the red light R1 and green light G1 provided by the lighting device may include the emission components of red and green light sources, therefore the second light source timing signals SR2 and SG2 are at a high logic level, while the second light source timing signal SB2 is at a low logic level. As another example, the blue light B1 provided by the lighting device may include the emission components of red, green, and blue light sources, therefore the second light source timing signals SR2, SG2, and SB2 are all at a high logic level.

[0025] Furthermore, the lookup table may also include the driving current ratios for multiple light sources. The control module 106 can also generate the driving current for each light source according to the lookup table and supply it to the driving module 108. More specifically, the control circuit 206 can generate the driving current for each light source according to the lookup table. For example, such as... Figure 5 As shown, the red light R1 provided by the lighting device may include the light-emitting components of a red light source and a green light source. The control module 106 can determine the ratio of the driving currents supplied to the red, green, and blue light sources respectively to enable the lighting device to provide red light R1 by referring to a lookup table. For example, in this embodiment, the ratio of the driving currents IR, IG, and IB supplied to the red, green, and blue light sources is 1:0.5:0. That is, assuming the driving current IR supplied to the red light source is 1mA, the driving currents IG and IB supplied to the green and blue light sources are 0.5mA and 0mA respectively. Similarly, the ratio of the driving currents IR, IG, and IB supplied to the red, green, and blue light sources respectively to enable the lighting device to provide green light G1 can be, for example, 0.8:1:0, and the ratio of the driving currents IR, IG, and IB supplied to the red, green, and blue light sources respectively to enable the lighting device to provide blue light B1 can be, for example, 0.4:0.4:1. The ratio of the driving currents among the red, green, and blue light sources can be designed differently depending on the actual situation.

[0026] The logic circuit 210 can output multiple first light source driving signals according to multiple first light source timing signals (e.g., first light source timing signals SR1, SG1 and SB1), output multiple second light source driving signals according to multiple second light source timing signals (e.g., second light source timing signals SR2, SG2 and SB2), and output the driving current provided by the control module 106 to the driving module 108.

[0027] The driving module 108 can drive the multiple light sources (e.g., red, green, and blue light sources) included in the light source module 102 to emit light in a non-overlapping light emission sequence according to the multiple first light source driving signals and the driving currents (e.g., driving currents IR, IG, and IB) of each light source provided by the control module 106, or drive the multiple light sources included in the light source module 102 to emit light in an overlapping light emission sequence according to the multiple second light source driving signals and the driving currents of each light source provided by the control module 106.

[0028] In this way, the control module 106 converts the bit control signal into multiple first light source timing signals, converts the multiple first light source timing signals into multiple second light source timing signals according to the lookup table and generates corresponding driving currents for each light source, generates multiple corresponding second light source driving signals according to the multiple second light source timing signals, and drives multiple light sources according to the multiple second light source driving signals and corresponding driving currents through the driving module. This allows multiple light sources to have overlapping emission timing, thereby improving the brightness of the projected image of the projection device and meeting the color gamut requirements of the projection device.

[0029] Furthermore, the method for driving the light source module 102 can be as follows: Figure 6 As shown, in this embodiment, the logic circuit 210 may include buffer gates B1-B3 and switching circuits SW1-SW3. The light source module may include red, green, and blue light-emitting diodes DR, DG, and DB. Buffer gates B1-B3 are coupled to the control circuit 206 and the driving module 108. Switching circuits SW1-SW3 are coupled to the control circuit 206, the reference voltage VR, and the driving module 108. The anodes of the light-emitting diodes DR, DG, and DB are respectively coupled to the driving module 108. The cathodes of the light-emitting diodes DR, DG, and DB are grounded together. In this embodiment, the light-emitting diodes DR, DG, and DB are coupled in a common-cathode manner. Common-cathode driving reduces the energy consumption of the components. In other embodiments, they can also be coupled in a common-anode manner. Buffer gates B1-B3 are used to output the driving current corresponding to each light source DR, DG, and DB (e.g., ...). Figure 5 The driving currents IR, IG, and IB in the embodiment (but not limited to these) are provided to the light source module 102 through the driving module 108.

[0030] Switching circuits SW1 to SW3 can respond to multiple first light source timing signals and select to output multiple first light source timing signals as multiple first light source driving signals, or respond to multiple second light source timing signals and select to output multiple second light source driving signals based on a reference voltage. For example, when LEDs DR, DG, and DB emit light in a non-overlapping emission timing mode, control circuit 206 can keep the second light source timing signals SR2, SG2, and SB2 at a low logic level (i.e., control circuit 206 provides a low logic level reference voltage VR to switching circuits SW1 to SW3, preventing the second light source timing signals SR2, SG2, and SB2 from being output), and cause switching circuits SW1 to SW3 to output first light source timing signals with non-overlapping emission timing as first light source driving signals, for example, they can... Figure 3 The first light source timing signals SR1, SG1, and SB1 shown serve as the first light source driving signals, but are not limited to this. When the light-emitting diodes DR, DG, and DB emit light in a mode of overlapping emission timing, the control circuit 206 can adjust the logic levels of the second light source timing signals SR2, SG2, and SB2 according to the emission requirements of the lighting device to control the emission timing of the light-emitting diodes DR, DG, and DB. For example, the logic levels of the second light source timing signals SR2, SG2, and SB2 can be set as follows: Figure 4 As shown, but not limited to this. When the second light source timing signals SR2, SG2, and SB2 are at a high logic level (i.e., the control circuit 206 provides a high logic level reference voltage VR to the switching circuits SW1-SW3, preventing the first light source timing signals SR1, SG1, and SB1 from being output), the switching circuits SW1-SW3 select to output the second light source driving signal. In this embodiment, the reference voltage VR used as the second light source driving signal is at a high logic level, but it is not limited to this. When the second light source timing signals SR2, SG2, and SB2 are at a low logic level (i.e., the control circuit 206 provides a low logic level reference voltage VR to the switching circuits SW1-SW3, preventing the second light source timing signals SR2, SG2, and SB2 from being output), the switching circuits SW1-SW3 select the first light source timing signals SR1, SG1, and SB1 as the second light source driving signal.

[0031] Thus, the driving module 108 can determine the light-emitting diodes (LEDs) emitting light from the first light source driving signal or the second light source driving signal, and can determine the magnitude of the current used to drive LEDs DR, DG, and DB from the driving currents IR, IG, and IB, and can control the light-emitting state of LEDs DR, DG, and DB as needed. It is worth noting that in this embodiment, the cathodes of LEDs DR, DG, and DB are commonly coupled to a reference voltage, which can reduce power consumption. However, in some embodiments, the coupling method of LEDs DR, DG, and DB can also be that the cathodes of multiple LEDs DR, DG, and DB are respectively coupled to the corresponding light source driving circuits, and the anodes of LEDs DR, DG, and DB are commonly coupled to the reference voltage of the control circuit 206, and is not limited to the coupling method of this embodiment.

[0032] Figure 7 This is a flowchart of a light source driving method for a lighting device according to an embodiment of the present invention. As can be seen from the above embodiment, the light source driving method for the lighting device may include the following steps: First, a processing module generates a bit control signal based on an image signal (step S702). Next, a control module converts the bit control signal into multiple first light source timing signals, converts the multiple first light source timing signals into multiple second light source timing signals according to a lookup table, generates a driving current corresponding to each light source according to the lookup table, outputs multiple first light source driving signals corresponding to the multiple light sources according to the multiple first light source timing signals, and outputs multiple second light source driving signals corresponding to the multiple light sources according to the multiple second light source timing signals (step S704), wherein the lookup table may include the driving current ratio corresponding to the multiple light sources. Then, a driving module drives the multiple light sources according to the multiple first light source driving signals and driving currents to enable the multiple light sources to have non-overlapping emission timing sequences, and drives the multiple light sources according to the multiple second light source driving signals and driving currents to enable the multiple light sources to have overlapping emission timing sequences (step S706).

[0033] In summary, the control module of this invention can convert bit control signals into multiple first light source timing signals, and then convert these signals into multiple second light source timing signals according to a lookup table. Compared to traditional projection devices, this invention can quickly generate the corresponding driving current for each light source based on the lookup table, and generate corresponding second light source driving signals based on the multiple second light source timing signals. The driving module can drive multiple light sources according to the multiple second light source driving signals and their corresponding driving currents, enabling the multiple light sources to have overlapping emission timings, thereby improving the brightness of the projected image and meeting the color gamut requirements of the projection device. The projection device of this invention can adjust the emission timings of multiple light sources to overlap or not overlap depending on the actual application, thus adapting to many different application scenarios.

[0034] Although the present invention has been disclosed by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined by the claims.

Claims

1. A lighting device, characterized in that, The lighting device includes a light source module, a processing module, a control module, and a drive module, wherein... The light source module includes multiple light sources; The processing module is used to generate bit control signals based on the image signals; The control module is coupled to the processing module and is used to convert the bit control signal into multiple first light source timing signals, and to convert the multiple first light source timing signals into multiple second light source timing signals according to a lookup table. The drive current corresponding to each of the plurality of light sources is generated according to the lookup table. Based on the timing signals of the plurality of second light sources, output a plurality of second light source driving signals corresponding to the plurality of light sources. The lookup table includes the correspondence between the timing signals of the plurality of first light sources and the timing signals of the plurality of second light sources, as well as the required proportion of driving current to be provided to the plurality of light sources respectively; as well as The driving module is coupled to the control module and the light source module, and is used to drive the multiple light sources according to the multiple second light source driving signals and the driving current so that the multiple light sources have overlapping emission timing.

2. The lighting device according to claim 1, characterized in that, The control module includes a first logic circuit, a control circuit, and a second logic circuit, wherein... The first logic circuit is coupled to the control module to convert the bit control signal into the timing signals of the plurality of first light sources; The control circuit is coupled to the first logic circuit and is used to convert the timing signals of the plurality of first light sources into the timing signals of the plurality of second light sources according to the lookup table, and to generate the driving current corresponding to each of the plurality of light sources according to the driving current ratio of the lookup table. as well as The second logic circuit is coupled to the control circuit and the driving module, and is used to output the multiple second light source driving signals according to the multiple second light source timing signals, and output the driving current to the driving module.

3. The lighting device according to claim 2, characterized in that, The second logic circuit includes multiple buffer gates and multiple switching circuits, wherein The plurality of buffer gates are coupled to the control circuit and the drive module to output the drive current corresponding to each of the plurality of light sources to the light source module; as well as The plurality of switching circuits are respectively coupled to the control circuit and the reference voltage, and select the output timing signals of the plurality of second light sources as driving signals of the plurality of second light sources according to the reference voltage.

4. The lighting device according to claim 1, characterized in that, The plurality of light sources include a plurality of light-emitting diodes (LEDs), the anodes of the plurality of LEDs are respectively coupled to a driving module, and the cathodes of the plurality of LEDs are commonly coupled to a reference voltage.

5. The lighting device according to claim 1, characterized in that, The plurality of light sources include a plurality of light-emitting diodes (LEDs), the cathodes of the plurality of LEDs are respectively coupled to the driving module, and the anodes of the plurality of LEDs are commonly coupled to the control module.

6. A projection device, characterized in that, The projection device includes an illumination device, a light valve, and a projection lens, wherein... The lighting device includes a light source module, a processing module, a control module, and a drive module, wherein... The light source module includes multiple light sources, which are used to provide illumination beams; The processing module is used to generate bit control signals based on the image signals; The control module is coupled to the processing module and is used to convert the bit control signal into multiple first light source timing signals, and to convert the multiple first light source timing signals into multiple second light source timing signals according to a lookup table. The drive current corresponding to each of the plurality of light sources is generated according to the lookup table. Based on the timing signals of the plurality of second light sources, output a plurality of second light source driving signals corresponding to the plurality of light sources. The lookup table includes the correspondence between the timing signals of the plurality of first light sources and the timing signals of the plurality of second light sources, as well as the required proportion of driving current to be provided to the plurality of light sources respectively; as well as The driving module is coupled to the control module and the light source module, and is used to drive the multiple light sources according to the multiple second light source driving signals and the driving current so that the multiple light sources have overlapping light emission timing. The light valve is located in the transmission path of the illumination beam to convert the illumination beam into an image beam; and The projection lens is located in the transmission path of the image beam and projects the image beam out of the projection device.

7. The projection device according to claim 6, characterized in that, The control module includes a first logic circuit, a control circuit, and a second logic circuit, wherein... The first logic circuit is coupled to the control module to convert the bit control signal into the timing signals of the plurality of first light sources; The control circuit is coupled to the first logic circuit and is used to convert the timing signals of the plurality of first light sources into the timing signals of the plurality of second light sources according to the lookup table, and to generate the driving current corresponding to each of the plurality of light sources according to the driving current ratio of the lookup table. as well as The second logic circuit is coupled to the control circuit and the driving module, and is used to output the multiple second light source driving signals according to the multiple second light source timing signals, and output the driving current to the driving module.

8. The projection device according to claim 7, characterized in that, The second logic circuit includes multiple buffer gates and multiple switching circuits, wherein The plurality of buffer gates are coupled to the control circuit and the drive module to output the drive current corresponding to each of the plurality of light sources to the light source module; as well as The plurality of switching circuits are respectively coupled to the control circuit and the reference voltage, and in response to the plurality of second light source timing signals, they select one of the plurality of first light source timing signals and the reference voltage as the plurality of second light source driving signals.

9. The projection device according to claim 6, characterized in that, The plurality of light sources include a plurality of light-emitting diodes (LEDs), the anodes of the plurality of LEDs are respectively coupled to a driving module, and the cathodes of the plurality of LEDs are commonly coupled to a reference voltage.

10. The projection device according to claim 6, characterized in that, The plurality of light sources include a plurality of light-emitting diodes (LEDs), the cathodes of the plurality of LEDs are respectively coupled to a driving module, and the anodes of the plurality of LEDs are commonly coupled to a control circuit.

11. A method for driving a light source in a lighting device, characterized in that, The lighting device includes multiple light sources, and the light source driving method of the lighting device includes: The processing module generates bit control signals based on the image signals; The control module converts the bit control signal into multiple first light source timing signals, converts these signals into multiple second light source timing signals according to a lookup table, generates driving currents corresponding to each of the multiple light sources based on the lookup table, and outputs multiple second light source driving signals corresponding to the multiple light sources based on the multiple second light source timing signals. The lookup table includes the correspondence between the multiple first light source timing signals and the multiple second light source timing signals, as well as the required proportions of driving currents to be provided to each of the multiple light sources. The driving module drives the multiple light sources according to the multiple second light source driving signals and the driving current, so that the multiple light sources have overlapping emission timing.

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