Projection apparatus and light source module

A projection apparatus and a light source module are provided. The light source module includes a light-emitting element string, a shunt module, and a control circuit. A first shunt circuit, a second shunt circuit, and a third shunt circuit of the shunt module are coupled to the light-emitting element string, and are adapted to provide a first shunt path, a second shunt path or a third shunt path, such that the light-emitting element string is still maintained to normally work when a light-emitting element/light-emitting elements is/are malfunctioned.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of China application serial no. 201710100362.1, filed on Feb. 23, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to an electronic apparatus, and particularly relates to a projection apparatus and a light source module.

Description of Related Art

It has advantages of a long service life, power saving, etc., to use a laser diode string to serve as a light source module, However, the service life of each laser diode in the laser diode string is not consistent, once a laser diode/laser diodes is/are malfunctioned after a period of use, the laser diode string cannot provide a light beam. Regarding the laser diode string applied to a projection apparatus/projector or a display to serve as a light source for producing light beam, projection quality of the projection apparatus is affected.

SUMMARY OF THE INVENTION

The invention is directed to a projection apparatus and a light source module. When a light-emitting element of a light-emitting element string is malfunctioned, a problem of being unable to provide light beam is mitigated/improved, so as to improve projection quality of the projection apparatus and optical quality of the light source module.

Other objects and advantages of the invention can be further illustrated by the technical features broadly embodied and described as follows.

In order to achieve one or a portion of or all of the objects or other objects, an embodiment of the invention provides a projection apparatus including a light source module, a light valve, and a projection lens. The light source module is adapted to provide an illumination beam, and the light source module includes a light-emitting element string, a shunt module, and a control circuit. The light-emitting element string has a first light-emitting portion, a second light-emitting portion, and a third light-emitting portion. The first light-emitting portion, the second light-emitting portion, and the third light-emitting portion include a plurality of light-emitting elements connected in series. The shunt module is coupled to the light-emitting element string, and the shunt module includes a first shunt circuit, a second shunt circuit, and a third shunt circuit. The first shunt circuit is connected in parallel with the first light-emitting portion to form a pair of first connection nodes on the light-emitting element string, and is adapted to provide a first shunt path. The second shunt circuit is connected in parallel with the second light-emitting portion to form a pair of second connection nodes on the light-emitting element string, and is adapted to provide a second shunt path. The third shunt circuit is connected in parallel with the third light-emitting portion to form a pair of third connection nodes on the light-emitting element string, and is adapted to provide a third shunt path. At least one light-emitting element between the pair of the first connection nodes, at least one light-emitting element between the pair of the second connection nodes, and at least one light-emitting element between the pair of the third connection nodes are not completely the same. The control circuit is coupled to the light-emitting element string, the first shunt circuit, the second shunt circuit, and the third shunt circuit, and is adapted to control the first shunt circuit, the second shunt circuit or the third shunt circuit to provide the first shunt path, the second shunt path or the third shunt path according to an output current of the light-emitting element string. The light-emitting element string is adapted to provide the illumination beam through the first shunt path, the second shunt path or the third shunt path. The light valve is located on a transmission path of the illumination beam, and is adapted to convert the illumination beam into an image beam. The projection lens is located on a transmission path of the image beam.

An embodiment of the invention provides a light source module. The light source module includes a light-emitting element string, a shunt module, and a control circuit. The light-emitting element string has a first light-emitting portion, a second light-emitting portion, and a third light-emitting portion. The first light-emitting portion, the second light-emitting portion, and the third light-emitting portion include a plurality of light-emitting elements connected in series. The shunt module is coupled to the light-emitting element string, and the shunt module includes a first shunt circuit, a second shunt circuit, and a third shunt circuit. The first shunt circuit is connected in parallel with the first light-emitting portion to form a pair of first connection nodes on the light-emitting element string, and is adapted to provide a first shunt path. The second shunt circuit is connected in parallel with the second light-emitting portion to form a pair of second connection nodes on the light-emitting element string, and is adapted to provide a second shunt path. The third shunt circuit is connected in parallel with the third light-emitting portion to form a pair of third connection nodes on the light-emitting element string, and is adapted to provide a third shunt path. At least one light-emitting element between the pair of the first connection nodes, at least one light-emitting element between the pair of the second connection nodes, and at least one light-emitting element between the pair of the third connection nodes are not completely the same. The control circuit is coupled to the light-emitting element string, the first shunt circuit, the second shunt circuit, and the third shunt circuit, and is adapted to control the first shunt circuit, the second shunt circuit or the third shunt circuit to provide the first shunt path, the second shunt path or the third shunt path according to an output current of the light-emitting element string.

According to the above description, in the embodiment of the invention, by using the first shunt circuit, the second shunt circuit, and the third shunt circuit coupled to the light-emitting element string to provide the shunt path(s) to guide current to the light-emitting element(s) that are not malfunctioned for emitting light beam, the problem that the light-emitting element string is unable to provide the light beam due to malfunction of a light-emitting element/light-emitting elements in the light-emitting element string is avoided and/or brightness attenuation caused by malfunction of a light-emitting element/light-emitting elements is mitigated, so as to effectively improve the projection quality of the projection apparatus and the optical quality of the light source module.

DESCRIPTION OF EMBODIMENTS

FIG. 1is a schematic diagram of a projection apparatus according to an embodiment of the invention. Referring toFIG. 1, in the embodiment, the projection apparatus100includes a light source module102, a light valve104, and a projection lens106. In the embodiment, the light source module102is, for example, a light source device, the light valve104is, for example, a digital micromirror device (DMD), a liquid crystal display (LCD) light valve, a liquid crystal on silicon (LCos) light valve. In the embodiment, the light valve104is disposed/located between the light source module102and the projection lens106. In the embodiment, the light source module102may provide an illumination beam S1. In the embodiment, the light valve104is disposed/located on a transmission path of the illumination beam S1, and is adapted to convert the illumination beam S1into an image beam S2. In the embodiment, the projection lens106is disposed/located on a transmission path of the image beam S2, and is adapted to convert the image beam S2into a projection beam S3, and projects the projection beam S3onto a screen (not shown), so as to display a projection image on the screen.

FIG. 2is a schematic diagram of a light source module according to an embodiment of the invention. Referring toFIG. 2, in the embodiment, the light source module102includes a light-emitting element string202, a shunt module DMI, and a control circuit210. In the embodiment, the control circuit210is coupled to the light-emitting element string202, and the light-emitting element string202is coupled between a voltage source used for providing an operation voltage VCC and the control circuit210. In the embodiment, the light-emitting element string202has a first light-emitting portion, a second light-emitting portion, and a third light-emitting portion (which are described later). The first light-emitting portion includes at least one first light-emitting element, the second light-emitting portion includes at least one second light-emitting element, and the third light-emitting portion includes at least one third light-emitting element. To be specific, in the embodiment, the light-emitting element string202includes the first light-emitting portion composed of light-emitting elements L1, L2, L3, and L4(for example, the first light-emitting elements) connected in series, the second light-emitting portion composed of light-emitting elements L5, L6, L7, and L8(for example, the second light-emitting elements) connected in series, and the third light-emitting portion composed of the light-emitting elements L3, L4, L5, and L6(for example, the third light-emitting elements) connected in series. In the embodiment, the light-emitting elements L1-L8are, for example, implemented by laser diodes, though the invention is not limited thereto; for example, the light-emitting elements L1-L8may also be implemented by light-emitting diodes (LED), bulbs, or other light-emitting electronic elements. In the embodiment, the shunt module DMI may include a first shunt circuit204, a second shunt circuit206, and a third shunt circuit208. In the embodiment, the first shunt circuit204is connected in parallel with the first light-emitting portion (i.e. the light-emitting elements L1, L2, L3, and L4connected in series) to form a pair of first connection nodes N1(i.e. two first connection nodes N1) on the light-emitting element string202; the second shunt circuit206is connected in parallel with the second light-emitting portion (i.e. the light-emitting elements L5, L6, L7, and L8connected in series) to form a pair of second connection nodes N2(i.e. two second connection nodes N2) on the light-emitting element string202; the third shunt circuit208is connected in parallel with the third light-emitting portion (i.e. the light-emitting elements L3, L4, L5, and L6connected in series) to form a pair of third connection nodes N3(i.e. two third connection nodes N3) on the light-emitting element string202. Moreover, in the embodiment, the control circuit210is coupled to the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208. In the embodiment, the control circuit210is adapted to control the first shunt circuit204, the second shunt circuit206or the third shunt circuit208to provide a first shunt path, a second shunt path or a third shunt path according to an output current of the light-emitting element string202, so as to guide the current to the light-emitting elements of the light-emitting element string202that are not malfunctioned, and avoid the problem that all of the light-emitting elements in the light-emitting element string202cannot emit light due to malfunction of a part of the light-emitting elements of the light-emitting element string202. In brief, the control circuit210may control the first shunt circuit204to provide the first shunt path, and control the second shunt circuit206to provide the second shunt path, and control the third shunt circuit208to provide the third shunt path. In the embodiment, as shown inFIG. 2, the control circuit210, for example, controls the first shunt circuit204to provide the first shunt path, and controls the second shunt circuit206not to provide the second shunt path, and controls the third shunt circuit208not to provide the third shunt path.

For example, as shown inFIG. 2, the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208may be implemented by switches. In the embodiment, when the control circuit210detects that the output current of the light-emitting element string202is zero, it represents that at least one light-emitting element in the light-emitting element string202is malfunctioned, such that the current may not pass through each of the light-emitting elements L1-L8. In the embodiment, the control circuit210, for example, alternately turns on the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208, and alternately provides the first shunt path, the second shunt path, and the third shunt path, such that the light-emitting element string202may still maintain a normal operation. For example, in the embodiment ofFIG. 2, if the malfunctioned light-emitting element is at least one of the light-emitting elements L1-L4, the control circuit210may turn on the first shunt circuit204to provide the first shunt path, and does not turn on the second shunt circuit206and the third shunt circuit208, such that the current may pass through a current path of the first shunt circuit204and the light-emitting elements L5-L8for outputting to the control circuit210. When the control circuit210detects that the output current of the light-emitting element string202is not zero, it represents that the malfunctioned light-emitting element no longer prevents the light-emitting element string202from providing the illumination beam S1, therefore the control circuit210may stop trying to turn on other shunt circuits, or may stop alternately turning on the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208. Deduced by analogy, in other embodiment that is not illustrated, if the malfunctioned light-emitting element is at least one of the light-emitting elements L5-L8, the control circuit210may turn on the second shunt circuit206to provide the second shunt path, and does not turn on the first shunt circuit204and the third shunt circuit208, such that the current may pass through a current path of the light-emitting elements L1-L4and the second shunt circuit206for outputting to the control circuit210. In other embodiment that is not illustrated, if the malfunctioned light-emitting element is at least one of the light-emitting elements L3-L6, the control circuit210may turn on the third shunt circuit208to provide the third shunt path, and does not turn on the first shunt circuit204and the second shunt circuit206, such that the current may pass through a current path of the light-emitting elements L1-L2, the third shunt circuit208and the light-emitting elements L7-L8for outputting to the control circuit210.

According to the aforementioned embodiment, it is known that by using the first shunt circuit204coupled to the light-emitting element string202to provide the first shunt path, or using the second shunt circuit206coupled to the light-emitting element string202to provide the second shunt path, or using the third shunt circuit208coupled to the light-emitting element string202to provide the third shunt path, the current may be provided to the non-malfunctioned light-emitting elements to emit light. Moreover, according to the aforementioned embodiment, even if most of the light-emitting elements are malfunctioned, the light-emitting element string202is still maintained to continually provide the illumination beam S1, so as to make an effective use of the light-emitting element string202. In this way, the problem that the light-emitting element string is unable to work or the problem of brightness attenuation caused by malfunction of a part of the light-emitting elements is greatly mitigated, so as to effectively improve the projection quality of the projection apparatus. In other embodiment that is not illustrated, a current driver may be further adapted to compensate the brightness attenuation caused by the malfunctioned light-emitting elements, such that the light-emitting element string202having the malfunctioned light-emitting elements may still maintain a light-emitting brightness as that when the malfunction is not occurred. Moreover, in some embodiments, the light source module102may further include a storage memory adapted to store/record malfunction information of the light-emitting elements in the light-emitting element string202to serve as reference information for future maintenance/improvement of the light source module120or the projection uppercuts100. Moreover, big data analysis may be performed to the stored/recorded malfunction information to further obtain a big data database.

Operation status of the light-emitting element string202when the light-emitting elements are malfunctioned is described below with reference of a following table one.

The light-emitting element string202, for example, has 8 light-emitting elements L1-L8(though the invention is not limited thereto), when the number of the malfunctioned light-emitting element is one, i.e. the malfunctioned light-emitting element is probably L1, L2, L3, L4, L5, L6, L7or L8, i.e. the number of statuses of malfunction is 8, where when the malfunctioned light-emitting element is L1or L2, the light-emitting element string202may still normally work through the second shunt path or the third shunt path; when the malfunctioned light-emitting element is L3or L4, the light-emitting element string202may still normally work through the second shunt path; when the malfunctioned light-emitting element is L5or L6, the light-emitting element string202may still normally work through the first shunt path; and when the malfunctioned light-emitting element is L7or L8, the light-emitting element string202may still normally work through the first shunt path or the third shunt path. In brief, when the number of the malfunctioned light-emitting element is one, a chance of maintaining a normal operation of the light-emitting element string202is 100%.

Continually referring to the table one, in the embodiment, when the number of the malfunctioned light-emitting elements is two, it is known that the number of statuses of malfunction is 28 according to the table one. In the embodiment, when the malfunctioned light-emitting elements are L1and L2, the light-emitting element string202may still normally work through the second shunt path or the third shunt path. In the embodiment, when the malfunctioned light-emitting elements are L1and L3at the same time, or are L1and L4at the same time, or are L2and L3at the same time, or are L2and L4at the same time, the light-emitting element string202may still normally work through the second shunt path. In the embodiment, when the malfunctioned light-emitting elements are L1and L7at the same time, or are L1and L8at the same time, or are L2and L7at the same time, or are L2and L8at the same time, the light-emitting element string202may still normally work through the third shunt path. In the embodiment, when the malfunctioned light-emitting elements are L3and L4at the same time, or are L5and L6at the same time, the light-emitting element string202may still normally work through the first shunt path or the second shunt path. In the embodiment, when the malfunctioned light-emitting elements are L5and L7at the same time, or are L5and L8at the same time, or are L6and L7at the same time, or are L6and L8at the same time, the light-emitting element string202may still normally work through the first shunt path. In the embodiment, when the malfunctioned light-emitting elements are L7and L8, the light-emitting element string202may still normally work through the first shunt path or the third shunt path. According to the above description, it is known that when the number of the malfunctioned light-emitting elements is two (i.e. the number of statuses of malfunction is 28), the light-emitting element string202may still normally work through the first shunt path, the second shunt path or the third shunt path under the number of statuses of malfunction of 16, i.e. the chance of normal operation of the light-emitting element string202is 57%. In brief, even if the number of the malfunctioned light-emitting elements is two, the chance of normal operation of the light-emitting element string202is still more than 50%.

Continually referring to the table one, in the embodiment, when the number of the malfunctioned light-emitting elements is three, it is known that the number of statuses of malfunction is 56 according to the table one. In the embodiment, when the malfunctioned light-emitting elements are L1, L2, and L3at the same time, or are L1, L2, and IA at the same time, or are L1, L3, and L4at the same time, or are L2, L3, and L4at the same time, the light-emitting element string202may still normally work through the second shunt path. In the embodiment, when the malfunctioned light-emitting elements are L1, L2, and L7at the same time, or are L1, L2, and L8at the same time, or are L1, L7, and L8at the same time, or are L2, L7, and L8at the same time, the light-emitting element string202may still normally work through the third shunt path. In the embodiment, when the malfunctioned light-emitting elements are L5, L6, and L7at the same time, or are L5, L6, and L8at the same time, or are L5, L7, and L8at the same time, or are L6, L7, and L8at the same time, the light-emitting element string202may still normally work through the first shunt path. According to the above description, it is known that when the number of the malfunctioned light-emitting elements is three (i.e. the number of statuses of malfunction is 56), the light-emitting element string202may still normally work through the first shunt path, the second shunt path or the third shunt path under the number of statuses of malfunction of 12, i.e. the chance of normal operation of the light-emitting element string202is 21%. In brief, even if the number of the malfunctioned light-emitting elements is three, the chance of normal operation of the light-emitting element string202is still more than 20%.

For simplicity's sake, only one light-emitting element string202is illustrated in the embodiment, though in an actual application, the light source module102may include a plurality of light-emitting element strings202. For example, in an embodiment that is not illustrated, a light-emitting element array formed by a plurality of light-emitting element strings202may be connected in parallel between the voltage source used for providing the operation voltage VCC and the control circuit210, and the control circuit210may adjust the shunt circuit corresponding to each of the light-emitting element strings202according to the output current of each of the light-emitting element strings202, so as to make an effective use of the light-emitting element array. Moreover, in some embodiment, the light source module102may also store/record the malfunction information of the light-emitting elements in the light-emitting element array to serve as reference information for future maintenance/improvement of the light source module120or the projection uppercuts100.

FIG. 3is a schematic diagram of a light source module according to another embodiment of the invention. Referring toFIG. 3, in the embodiment, the first shunt circuit204may include switches SW1, SW2, resistors R1, R2, R3, and capacitors C1, C2; the second shunt circuit206may include switches SW3, SW4, resistors R4, R5, R6, and capacitors C3, C4; and the third shunt circuit208may include switches SW5, SW6, resistors R7, R8, R9, and capacitors C5, C6. In the embodiment, the switches SW1-SW6may be implemented by transistors. For example, in the embodiment, the switches SW1, SW3, SW5are, for example, implemented by metal-oxide-semiconductor field-effect transistors (MOSFET), and the switches SW2, SW4, SW6are, for example, implemented by bipolar junction transistors (BJT), though the invention is not limited thereto. In the embodiment, by using the BJTs to implement the switches SW2, SW4, SW6, manufacturing cost of the light source module may be reduced. In the embodiment, the switch SW1is coupled between a pair of first connection nodes N1, and the switch SW2is coupled between a control terminal of the switch SW1and a reference ground terminal used for providing a ground voltage. The control circuit210may control a turn-on state of the switch SW2, so as to control a turn-on state of the switch SW1to make the switch SW1to provide a first shunt path. In the embodiment, the resistor R1is coupled between the voltage source used for providing the operation voltage VCC and the control terminal of the switch SW1, the resistor R2is coupled between the control terminal of the switch SW1and a collector of the switch SW2, and the resistor R3is coupled between a control terminal of the switch SW2and the control circuit210. The capacitor C1is coupled between the control terminal of the switch SW1and the reference ground terminal used for providing the ground voltage, and the capacitor C2is coupled between the control terminal of the switch SW2and the reference ground terminal used for providing the ground voltage. In the embodiment, the resistors R1, R2and the capacitor C1(coupled to the control terminal of the switch SW1) and the resistor R3and the capacitor C2(coupled to the control terminal of the switch SW2) may be used for adjusting a bias magnitude of the control terminals of the switches SW1and SW2and a delay time of voltage variation, such that when the control circuit210provides a voltage to the first shunt circuit204to make the switch SW1to provide the first shunt path, the switches SW1and SW2may be indeed turned on/off and have a good turn-on time.

Similarly, in the embodiment, the SW3is coupled between a pair of second connection nodes N2, and the switch SW4is coupled between a control terminal of the switch SW3and the reference ground terminal used for providing the ground voltage. The control circuit210may control a turn-on state of the switch SW4, so as to control a turn-on state of the switch SW3to make the switch SW3to provide a second shunt path. In the embodiment, the resistor R4is coupled between the voltage source used for providing the operation voltage VCC and the control terminal of the switch SW3, the resistor R5is coupled between the control terminal of the switch SW3and the reference ground terminal used for providing the ground voltage, and the resistor R6is coupled between a control terminal of the switch SW4and the control circuit210. The capacitor C3is coupled between the control terminal of the switch SW3and the reference ground terminal used for providing the ground voltage, and the capacitor C4is coupled between the control terminal of the switch SW4and the reference ground terminal used for providing the ground voltage. In the embodiment, the resistors R4, R5and the capacitor C3(coupled to the control terminal of the switch SW3) and the resistor R6and the capacitor C4(coupled to the control terminal of the switch SW4) may be used for adjusting a bias magnitude of the control terminals of the switches SW3and SW4and a delay time of voltage variation, such that when the control circuit210provides a voltage to the second shunt circuit206to make the switch SW3to provide the second shunt path, the switches SW3and SW4may be indeed turned on/off and have a good turn-on time.

Similarly, in the embodiment, the switch SW5is coupled between a pair of third connection nodes N3, and the switch SW6is coupled between a control terminal of the switch SW5and the reference ground terminal used for providing the ground voltage. The control circuit210may control a turn-on state of the switch SW6, so as to control a turn-on state of the switch SW5to make the switch SW5to provide a third shunt path. In the embodiment, the resistor R7is coupled between the voltage source used for providing the operation voltage VCC and the control terminal of the switch SW5, the resistor R8is coupled between the control terminal of the switch SW5and a collector of the switch SW6, and the resistor R9is coupled between a control terminal of the switch SW6and the control circuit210. The capacitor C5is coupled between the control terminal of the switch SW5and the reference ground terminal used for providing the ground voltage, and the capacitor C6is coupled between the control terminal of the switch SW6and the reference ground terminal used for providing the ground voltage. In the embodiment, the resistors R7, R8and the capacitor C5(coupled to the control terminal of the switch SW5) and the resistor R9and the capacitor C6(coupled to the control terminal of the switch SW6) may be used for adjusting a bias magnitude of the control terminals of the switches SW5and SW6and a delay time of voltage variation, such that when the control circuit210provides a voltage to the third shunt circuit208to make the switch SW5to provide the third shunt path, the switches SW5and SW6may be indeed turned on/off and have a good turn-on time. In the embodiment, resistances of the resistors R1-R9and capacitances of the capacitors C1-C6may be respectively adjusted according to characteristics of the corresponding shunt paths. In some embodiments, the light source module102may not include the resistors R1-R9and the capacitors C1-C6, which is not limited by the invention.

Moreover, the control circuit210of the embodiment may include a current detection circuit302, an analog to digital converter (ADC)304, and a micro controller306. In the embodiment, the current detection circuit302is coupled between the light-emitting element string202and the ADC304, the ADC304is coupled between the current detection circuit302and the micro controller306, and the micro controller306is coupled to the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208. In the embodiment, the micro controller306is coupled between the first shunt circuit204and the ADC304, the micro controller306is coupled between the second shunt circuit206and the ADC304, and the micro controller306is coupled between the third shunt circuit208and the ADC304. In the embodiment, the current detection circuit302may detect a current output by the light-emitting element string202to output a current detection signal; the ADC304may receive the current detection signal from the current detection circuit302, and convert the current detection signal into a digital signal; and the micro controller306may receive the digital signal from the ADC304and output a voltage to the switches SW2, SW4, and SW6according to the digital signal, so as to control the switch SW to provide the first shunt path, or control the switch SW3to provide the second shunt path, or control the switch SW5to provide the third shunt path.

However, the coupling method of the first shunt circuit204, the second shunt circuit206, the third shunt circuit208, and the light-emitting element string202is not limited to the methods shown inFIG. 2andFIG. 3. For example, as long as at least one light-emitting element between the pair of first connection nodes N1, at least one light-emitting element between the pair of second connection nodes N2, and at least one light-emitting element between the pair of third connection nodes N3are not completely the same, it may serve as the coupling method of the first shunt circuit204, the second shunt circuit206, the third shunt circuit208, and the light-emitting element string202of the embodiment. To be specific,FIG. 4is a schematic diagram of a light source module according to another embodiment of the invention. Referring toFIG. 4, in the embodiment, the first light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L1, L2, and L3; the second light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L5, L6, L7, and L8; and the third light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L3, L4, L5, and L6. The first shunt circuit204, the second shunt circuit206, and the third shunt circuit208(or referred to as the switch SW1of the first shunt circuit204, the switch SW3of the second shunt circuit206, and the switch SW5of the third shunt circuit208) are respectively coupled in parallel with the first light-emitting portion (the light-emitting elements L1, L2, and L3), the second light-emitting portion (the light-emitting elements L5, L6, L7, and L5), and the third light-emitting portion (the light-emitting elements L3, L4, L5, and L6), so as to form a pair of first connection nodes N1, a pair of second connection nodes N2, and a pair of third connection nodes N3on the light-emitting element string202. Similarly, in the embodiment, the control circuit210may control the first shunt circuit204, the second shunt circuit206or the third shunt circuit208to provide the first shunt path, the second shunt path or the third shunt path according to the output current of the light-emitting element string202, so as to guide the current to the light-emitting elements of the light-emitting element string202that are not malfunctioned, and avoid the situation that all of the light-emitting elements of the light-emitting element string202cannot emit light.

Similarly,FIG. 5is a schematic diagram of a light source module according to another embodiment of the invention. Referring toFIG. 5, in the embodiment, the first light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L1, L2, L3, and L4; the second light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L6, L7, and L8; and the third light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L3, L4, L5, and L6. The first shunt circuit204, the second shunt circuit206, and the third shunt circuit208(or referred to as the switch SW1of the first shunt circuit204, the switch SW3of the second shunt circuit206, and the switch SW5of the third shunt circuit208) are respectively coupled in parallel with the first light-emitting portion (the light-emitting elements L1, L2, L3, and L4), the second light-emitting portion (the light-emitting elements L6, L7, and L8), and the third light-emitting portion (the light-emitting elements L3, L4, L5, and L6), so as to form a pair of first connection nodes N1, a pair of second connection nodes N2, and a pair of third connection nodes N3on the light-emitting element string202.

Similarly,FIG. 6is a schematic diagram of a light source module according to another embodiment of the invention. Referring toFIG. 6, in the embodiment, the first light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L1, L2, and L3; the second light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L6, L7, and L8; and the third light-emitting portion of the light-emitting element string202is composed of the light-emitting elements L3, L4, L5, and L6. The first shunt circuit204, the second shunt circuit206, and the third shunt circuit208(or referred to as the switch SW1of the first shunt circuit204, the switch SW3of the second shunt circuit206, and the switch SW5of the third shunt circuit208) are respectively coupled in parallel with the first light-emitting portion (the light-emitting elements L1, L2, and L3), the second light-emitting portion (the light-emitting elements L6, L7, and L8), and the third light-emitting portion (the light-emitting elements L3, L4, L5, and L6), so as to form a pair of first connection nodes N1, a pair of second connection nodes N2, and a pair of third connection nodes N3on the light-emitting element string202.

Moreover, in the aforementioned embodiments, although the light-emitting element string202having 8 light-emitting elements L1-L8is taken as an example to describe the light-emitting module102, the invention is not limited thereto. The light-emitting element string202may also include different number of the light-emitting elements. For example, as long as the method for coupling the first shunt circuit204, the second shunt circuit206, and the third shunt circuit208to the light-emitting element string202is that at least one light-emitting element between the pair of first connection nodes N1, at least one light-emitting element between the pair of second connection nodes N2, and at least one light-emitting element between the pair of third connection nodes N3are not completely the same, it may serve as the embodiment of the invention. To be specific,FIG. 7-FIG. 9are schematic diagrams of light source modules according to embodiments of the invention. In the embodiment ofFIG. 7-FIG. 9, the light-emitting element string702includes 3 light-emitting elements L1-L3. In the embodiment ofFIG. 7, a first light-emitting portion of a light-emitting element string702includes the light-emitting element L1, a second light-emitting portion of the light-emitting element string702includes the light-emitting element L3, and a third light-emitting portion of the light-emitting element string702includes the light-emitting element L2. In the embodiment ofFIG. 8, the first light-emitting portion of the light-emitting element string702includes the light-emitting elements L1and L2; the second light-emitting portion of the light-emitting element string702includes the light-emitting element L3; and the third light-emitting portion of the light-emitting element string702includes the light-emitting elements L2and L3. In the embodiment ofFIG. 9, the first light-emitting portion of the light-emitting element string702includes the light-emitting element L1; the second light-emitting portion of the light-emitting element string702includes the light-emitting elements L2and L3; and the third light-emitting portion of the light-emitting element string702includes the light-emitting elements L1and L2. Similarly, in the embodiments ofFIG. 7-FIG. 9, the control circuit210may control the first shunt circuit204, the second shunt circuit206or the third shunt circuit208to provide the first shunt path, the second shunt path or the third shunt path according to the output current of the light-emitting element string702, so as to guide the current to the light-emitting elements of the light-emitting element string202that are not malfunctioned, and avoid the situation that all of the light-emitting elements of the light-emitting element string202cannot emit light due to malfunction of a part of the light-emitting elements. Since the implementation method that the control circuit210controls the first shunt circuit204, the second shunt circuit206or the third shunt circuit208to provide the first shunt path, the second shunt path or the third shunt path according to the output current of the light-emitting element string202have been described in detail in the aforementioned embodiment, those skilled in the art may deduce the implementation of the embodiments ofFIG. 7-FIG. 9according to the aforementioned embodiment, and detailed thereof is not repeated.

In some embodiments, the first shunt circuit204may include MOSFETs and photo transistors (e.g. photo MOS), the second shunt circuit206may include MOSFETs and photo transistors, and the third shunt circuit208may include MOSFETs and photo transistors. For example,FIG. 10is a schematic diagram of a light source module according to another embodiment of the invention. In the embodiment, the first shunt circuit204may include switches SW7, SW8, a photo transistor PM1, resistors R10, R11, and a capacitor C8; the second shunt circuit206may include switches SW9, SW10, resistors R12, R13, and a capacitor C9; and the third shunt circuit208may include switches SW11, SW12, resistors R14, R15, and a capacitor C11. In the embodiment, the capacitors C7, C10are voltage stabilizing capacitors of the operation voltage VCC. In the embodiments, the switches SW7-SW12are implemented by transistors, and the switches SW7-SW12are, for example, implemented by N-type MOSFETs, though the invention is not limited thereto. In the embodiment, a coupling relationship of the switches SW7-SW12, the photo transistors PM1-PM3, the resistors R10-R15, the capacitors C7-C11, the control circuit210, and the light-emitting element string202is as shown inFIG. 10. In the embodiment, the micro controller306may apply a control voltage to the switches SW8, SW10, and SW12to control turn-on states of the switches SW7, SW9, and SW11, so as to provide the corresponding shunt path. Similarly, the resistors R10-R5and the capacitors C7-C11of the embodiment may be used for adjusting a bias magnitude of the control terminals of each of the switches and a delay time of voltage variation, such that the switches SW7, SW9, and SW11may be indeed turned on/off and have a good turn-on time to provide the shunt path.

In summary, in the embodiments of the invention, by using the first shunt circuit, the second shunt circuit, and the third shunt circuit coupled to the light-emitting element string to provide the shunt paths to guide the current to the light-emitting elements that are not malfunctioned for emitting light, the problem that the light-emitting element string is unable to provide the light beam due to malfunction of a light-emitting element/light-emitting elements in the light-emitting element string is avoided and/or brightness attenuation caused by malfunction of a light-emitting element/light-emitting elements is mitigated, so as to effectively improve the projection quality of the projection apparatus and the optical quality of the light source module.