WO2018040633A1

WO2018040633A1 - Light source device and projector

Info

Publication number: WO2018040633A1
Application number: PCT/CN2017/086164
Authority: WO
Inventors: 张正德; 李屹
Original assignee: 深圳市光峰光电技术有限公司
Priority date: 2016-06-07
Filing date: 2017-05-26
Publication date: 2018-03-08
Also published as: CN107484306A

Abstract

The prevent invention discloses a light source device and a projector. The light source device comprises: a light-emitting element series comprising a plurality of light-emitting elements connected in series, wherein, with respect to a current flow direction of any two adjacent light-emitting elements, the negative electrode of the preceding light-emitting element is connected to the positive electrode of the following light-emitting element; and a control circuit, for detecting a voltage between the positive electrode and the negative electrode of each light-emitting element, determining, according to a detection result, whether an open circuit has occurred in the light-emitting element, and short-circuiting the negative electrode and the positive electrode of the light-emitting element if the open circuit has occurred in the light-emitting element. The light source device determines whether an open circuit has occurred in each of the light-emitting elements by the detection of the control circuit. Upon detecting an open circuit in the light-emitting element, the positive electrode and the negative electrode of the light-emitting element with an open circuit are short-circuited to keep the light-emitting element series turned on, ensuring normal operation of the light-emitting element series, and preventing malfunctioning of the entire light-emitting series caused by an open circuit occurring in a part of the light-emitting elements.

Description

Light source device and projector

Technical field

The present invention relates to the field of projection devices, and more particularly to a light source device and a projector.

Background technique

In general, the power of a single illuminating element is relatively small; for example, the power of a single laser diode is typically about 10 W, which can produce 180 lumens of brightness. The brightness of light source devices of some devices (such as projectors) is generally more than 3000, so that the light source device requires a plurality of light-emitting element arrays to meet higher brightness requirements.

There are generally two types of driving methods for array light-emitting elements, one is used in series, and the other is used in parallel. Parallel use is to separately drive each light-emitting element separately. The biggest disadvantage of this method is that the drive current is huge, the heat is large, and the efficiency is not high. Due to the above shortcomings of the parallel use mode, the serial use mode is often used at this stage. The series use mode has a small driving current and low cost.

technical problem

However, one major disadvantage of using in series is that once one of the light-emitting elements is broken, all of the light-emitting elements in the series circuit of the entire light-emitting element will not function properly.

Therefore, when the light-emitting elements in the array light-emitting elements are used in series, how to overcome the problem that the series circuit of the light-emitting elements cannot be normally used due to the disconnection of the partial light-emitting elements is a problem to be solved.

Technical solution

In order to solve the above problems, the present invention provides a light source device and a projector, wherein the light source device detects whether or not each of the light-emitting elements is broken by a control circuit, and detects a positive electrode of the light-emitting element that is broken when a light-emitting element is broken. And the negative electrode is short-circuited, so that the light-emitting element string is in the path, the normal operation of the light-emitting element string is ensured, and the problem that the entire light-emitting element string cannot work normally due to the disconnection problem of the partial light-emitting element string is avoided.

In order to achieve the above object, the present invention provides the following technical solutions:

A light source device comprising:

a light-emitting element string having a plurality of light-emitting elements connected in series, and for any two adjacent light-emitting elements, a positive electrode of the light-emitting element is connected to a negative electrode of the former light-emitting element in a current flow direction;

a control circuit for detecting a voltage between the positive electrode and the negative electrode of the light-emitting element, determining whether the light-emitting element is disconnected based on the detection result, and if so, short-circuiting the positive electrode and the negative electrode of the light-emitting element.

Preferably, in the above light source device, the control circuit includes: a controller, a plurality of voltage detecting circuits corresponding to the light emitting elements, and a plurality of switching circuits corresponding to the light emitting elements;

The voltage detecting circuit is configured to acquire a test voltage between a positive electrode and a negative electrode of the corresponding light emitting element, and generate a feedback signal when the test voltage is greater than a rated turn-on voltage of the light emitting element, and send the feedback signal Giving the controller

After acquiring the feedback signal, the controller generates a switch control signal according to the feedback signal, where the switch control signal is used to control a switch circuit corresponding to the light-emitting element to be turned on, and a positive electrode and a negative electrode of the light-emitting element are Short.

In one embodiment, in the above light source device, the voltage detecting circuit comprises: a Zener diode and a photocoupler;

Wherein the photocoupler has a first input end, a second input end and an output end; the first input end is connected to the anode of the Zener diode, and the cathode of the Zener diode and the corresponding light-emitting element a positive input connection; the second input end is connected to a negative electrode of the corresponding light-emitting element; the output end is connected to the controller; when the light-emitting element is disconnected, the Zener diode is reverse-punched, so that The photocoupler is turned on, and the photocoupler generates the feedback signal;

When the voltage detecting circuit generates the feedback signal, it is sent to the controller through the output terminal.

In one embodiment, in the above light source device, the switch circuit includes: a relay having a third input end, a fourth input end, and a first control end;

Wherein the third input end is connected to the positive pole of the corresponding light-emitting element; the fourth input end is connected to the negative pole of the corresponding light-emitting element; the first control end is connected to the controller;

When the controller generates the switch control signal, the switch control signal is sent to the first control end of the corresponding relay.

In one embodiment, in the above light source device, the light emitting element string is connected to a first voltage source, and the first voltage source is used to provide an operating current for the light emitting element;

The relay is coupled to a second voltage source for providing a rated operating voltage to the relay;

Wherein the first voltage source is different from the second voltage source.

In one embodiment, in the above light source device, the switch circuit includes: a switch tube having: a fifth input end, a sixth input end, and a second control end;

The fifth input end is connected to the positive pole of the corresponding light-emitting element; the sixth input is connected to the negative pole of the corresponding light-emitting element; and the second control end is connected to the controller;

When the controller generates the switch control signal, the switch control signal is sent to a second control end of the corresponding switch tube.

In one embodiment, in the above light source device, the switch tube is a MOS tube.

In one embodiment, in the above light source device, one end of the string of light emitting elements is connected to a first port, and the first port is used to connect a first voltage source;

The other end of the string of light emitting elements is connected to a second port for connecting a constant current driver for adjusting a current value of the string of light emitting elements to adjust the light emission of the light source device strength.

In one embodiment, the light emitting element is a laser diode or a light emitting diode.

Beneficial effect

The present invention also provides a projector comprising: the light source device according to any of the above.

According to the above description, the light source device provided by the technical solution of the present invention includes: a light-emitting element string having a plurality of light-emitting elements connected in series, and a current flow direction for any adjacent two light-emitting elements And a control circuit, wherein the control circuit is configured to detect a voltage between the positive electrode and the negative electrode of the light-emitting element, and determine, according to the detection result, whether the light-emitting element is open, if That is, the positive electrode and the negative electrode of the light-emitting element are short-circuited. The light source device detects whether each of the light-emitting elements is disconnected by the control circuit, and when detecting that the light-emitting element is disconnected, short-circuits the positive electrode and the negative electrode of the light-emitting element that is broken, so that the light-emitting element string is in the path, and the light-emitting element string is ensured. The normal operation avoids the problem that the entire illuminating element string cannot work normally due to the problem of disconnection of some of the illuminating element strings. The projector according to the technical solution of the present invention adopts the above-mentioned light source device, which avoids the problem that the light source device of the conventional projector cannot work normally due to the disconnection problem of some of the light-emitting elements.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can obtain other drawings according to the provided drawings without any creative work.

1 is a schematic structural diagram of a light source device according to an embodiment of the present invention;

2 is a schematic diagram of a principle of voltage detection according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another light source device according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As described in the background art, when the light-emitting elements in the array light-emitting elements are used in series, how to overcome the problem that the light-emitting element series circuit cannot be normally used due to the partial light-emitting element disconnection is a problem to be solved at present.

In order to solve the above problems, an embodiment of the present invention provides a light source device, where the light source device includes:

It can be seen that the light source device detects whether each of the light-emitting elements is disconnected by the control circuit, and when detecting that the light-emitting element is disconnected, short-circuits the positive electrode and the negative electrode of the light-emitting element that is broken, so that the light-emitting element string is in the path to ensure light emission. The normal operation of the component string avoids the problem that the entire illuminating component string cannot work normally due to the problem of disconnection of the partial illuminating component string.

In order to make the technical solutions provided by the embodiments of the present invention clearer, the foregoing solutions are described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram of a light source device according to an embodiment of the present invention. The light source device includes: a light-emitting element string 11 and a control circuit 12 .

The light-emitting element string 11 has a plurality of light-emitting elements 111 connected in series. For any two adjacent light-emitting elements 111, in the direction of current flow, the anode of the previous light-emitting element 111 is connected to the anode of the first light-emitting element 1111, that is, all The light emitting elements 111 are connected in series. The current flow direction refers to the direction from the positive electrode to the negative electrode of the light-emitting element 111.

In the light source device shown in Fig. 1, only two connected light-emitting elements are shown. The number of the light-emitting elements 111 in the light source device can be set according to the brightness requirement of the light source device. The number of the light-emitting elements 111 in the light source device is not limited in the embodiment of the present invention.

The control circuit 12 is configured to detect a voltage between the positive electrode and the negative electrode of the light-emitting element 111, determine whether the light-emitting element is open according to the detection result, and if so, short-circuit the positive electrode and the negative electrode of the light-emitting element.

As shown in FIG. 1 , the control circuit 12 includes a controller 123 , a plurality of voltage detecting circuits 121 corresponding to the light emitting elements 111 , and a plurality of switch circuits 122 corresponding to the light emitting elements 111 .

The voltage detecting circuit 121 is configured to acquire a test voltage between the positive electrode and the negative electrode of the corresponding light-emitting element 111, and generate a feedback signal when the test voltage is greater than the rated turn-on voltage of the light-emitting element 111, A feedback signal is sent to the controller 123. After acquiring the feedback signal, the controller 123 generates a switch control signal according to the feedback signal, where the switch control signal is used to control the switch circuit 122 corresponding to the light-emitting element 111 to be turned on, and the light-emitting element 111 is turned on. The positive electrode and the negative electrode are shorted.

It can be seen that, in the control circuit, each of the light-emitting elements 111 is provided with a voltage detecting circuit 121 for detecting the voltage between the positive electrode and the negative electrode of the light-emitting element 111. The two input ends of the respective voltage detecting circuits 121 are respectively connected to the positive electrode and the negative electrode of the corresponding light emitting element 111 for detecting the voltage between the positive electrode and the negative electrode of the light emitting element 111.

If a light-emitting element 111 is broken due to a fault, the voltage between its positive and negative electrodes will increase. It can be judged from this whether or not the light-emitting element 111 is broken. Since the two input ends of the respective voltage detecting circuits 121 are respectively connected to the positive electrode and the negative electrode of the corresponding light emitting element 111, if a plurality of light emitting elements 111 are disconnected in the light emitting element string 11, the operating voltage can be transmitted through the voltage detecting circuit 121 to ensure the voltage. The correctness of the test. The principle of voltage detection by the voltage detecting circuit 121 is as shown in FIG. 2.

Referring to the drawings, FIG. 2 is a schematic diagram of a principle of voltage detection according to an embodiment of the present invention. If the light-emitting element 111A and the light-emitting element 111B are disconnected in the light-emitting element string 11, the light-emitting element 111A and the light-emitting element 111B may be adjacent or not adjacent. The voltage detecting circuit 121A is for detecting the voltage between the two poles of the light-emitting element 111A. If the voltage detecting circuit 121B is used to detect the voltage between the two poles of the light-emitting element 111B. The voltage detecting circuit 121B can be connected to the power supply terminal through the voltage detecting circuit 121A to test the voltage between the two poles of the light-emitting element 111B, and the problem that the voltage between the two poles of the light-emitting element 111B cannot be normally tested due to the disconnection of the light-emitting element 111A does not occur.

As shown in FIG. 1 , in the light source device of the embodiment of the invention, the voltage detecting circuit 121 includes a Zener diode D and a photocoupler M. Wherein, the photocoupler M has a first input end, a second input end and an output end. The first input terminal is connected to the anode of the Zener diode D, and the cathode of the Zener diode D is connected to the anode of the corresponding LED element 111. The second input terminal is connected to the negative electrode of the corresponding light-emitting element 111; the output terminal is connected to the controller 123. When the light emitting element 111 is disconnected, the Zener diode D is reversely broken down, so that the photocoupler M is turned on, the photocoupler M generates the feedback signal, and sends the feedback signal The controller 123 is given. When the voltage detecting circuit 121 generates the feedback signal, it is sent to the controller 123 through the output terminal.

As shown in FIG. 1 , in the light source device of the embodiment of the present invention, the switch circuit 122 includes a relay Q1 having a third input end, a fourth input end, and a first control end. The third input end is connected to the positive electrode of the corresponding light-emitting element 111; the fourth input end is connected to the negative electrode of the corresponding light-emitting element 111; and the first control end is connected to the controller 123. When the controller 123 generates the switch control signal, the switch control signal is sent to the first control end of the corresponding relay Q1. When the first control terminal of the relay Q1 is configured to the switch control signal, the third input terminal and the fourth input terminal are controlled to be turned on, so that the corresponding light-emitting elements 111 are short-circuited.

In the light source device shown in FIG. 1, the forward voltage of the Zener diode D is greater than the rated ON voltage of the light-emitting element 111, that is, greater than the forward voltage of the light-emitting element 111. When the light-emitting element 111 is in the path, since the forward voltage of the Zener diode D is larger than the rated ON voltage of the light-emitting element 111, the Zener diode D is turned off. When a light-emitting element 111 is disconnected, the voltage between the positive electrode and the negative electrode of the light-emitting element 111 becomes large, and the Zener diode D corresponding to the light-emitting element 111 is reversely broken, thereby causing the corresponding photocoupler M of the light-emitting element 111. Turns on to generate a feedback signal. The controller 123 generates a switch control signal according to the feedback signal, and controls the third input end and the fourth input end of the relay Q1 corresponding to the light-emitting element 111 to be turned on, thereby short-circuiting the positive electrode and the negative electrode of the light-emitting element 111.

The light emitting element string is connected to a first voltage source VDD1 for supplying an operating current to the light emitting element 111. When the number of the light-emitting elements 111 that emit light in the light-emitting element string is constant, the light-emitting intensity of the light source device depends on the magnitude of the current in the light-emitting element string when the first voltage source VDD1 acts on the light-emitting element string. Under the premise of ensuring the normal operation of the light-emitting element 111, the greater the current in the light-emitting element string, the greater the brightness of the light source device, and the smaller the current in the light-emitting element string, the smaller the brightness of the light source device.

The relay Q is coupled to a second voltage source VDD2 for providing a nominal operating voltage to the relay Q. Optionally, all of the relays Q are identical, and all of the included relays Q are connected to the same second voltage source VDD2.

As described above, the current in the light-emitting element string varies depending on the brightness of the light source device, and therefore, the operating voltage when the light-emitting element 111 is turned on is not constant. The relay Q requires a stable rated operating voltage. Therefore, in the embodiment of the present invention, the first voltage source VDD1 is different from the second voltage source VDD2.

Referring to FIG. 3, FIG. 3 is a schematic structural diagram of another light source device according to an embodiment of the present invention. The light source device is different from the light source device shown in FIG. 1 in that the implementation manner of the switch circuit 122 is different, and in the embodiment shown in FIG. The switch circuit 122 includes a switch tube Q2. The switch tube Q2 has a fifth input end, a sixth input end, and a second control end. The fifth input terminal is connected to the positive electrode of the corresponding light-emitting element 111; the sixth input is connected to the negative electrode of the corresponding light-emitting element 111; and the second control terminal is connected to the controller 123. When the controller 123 generates the switch control signal, the switch control signal is sent to the second control end of the corresponding switch tube Q2.

In the light source device shown in FIG. 3, the forward voltage of the Zener diode D is also larger than the rated ON voltage of the light-emitting element 111, that is, larger than the forward voltage of the light-emitting element 111. When the light-emitting element 111 is in the path, since the forward voltage of the Zener diode D is larger than the rated ON voltage of the light-emitting element 111, the Zener diode D is turned off. When a light-emitting element 111 is disconnected, the voltage between the positive electrode and the negative electrode of the light-emitting element 111 becomes large, and the Zener diode D corresponding to the light-emitting element 111 is reversely broken, thereby causing the corresponding photocoupler M of the light-emitting element 111. Turns on to generate a feedback signal. The controller 123 generates a switch control signal according to the feedback signal, and controls the fifth input end and the sixth input end of the switch tube Q2 corresponding to the light-emitting element 111 to be short-circuited.

In the embodiment shown in FIG. 3, the switch tube Q2 may be a MOS tube. Specifically, the switch tube Q2 can be an NMOS tube or a PMOS tube.

As shown in FIG. 1 or FIG. 3, in the light source device of the embodiment of the present invention, one end of the light-emitting element string 11 is connected to a first port, and the first port is used to connect a first voltage source VDD1; The other end of the light-emitting element string 11 is connected to a second port for connecting a constant current driver for adjusting a current value of the light-emitting element string to adjust the light-emitting intensity of the light source device . Wherein, the cross current driver can be used to adjust the current of the light emitting element string 11 to adjust the light emitting brightness of the light source device. Specifically, the current of the light-emitting element string 11 can be divided into a plurality of levels of different sizes by a cross-flow driver. The larger the current, the greater the brightness of the light source device, and vice versa, the smaller the brightness.

It should be noted that, in the light source device of the embodiment of the present invention, the voltage detecting circuit and the switching circuit are all schematic descriptions, and the specific circuit structure includes but is not limited to the embodiments described in the embodiments of the present invention. Embodiments in which the protection resistors, capacitors, and other protection elements are added in the embodiments of the embodiments of the present invention also belong to the inventive concept of the embodiments of the present invention.

It can be seen from the above description that in the light source device of the embodiment of the invention, all the light-emitting elements are used in series, the driving current is small, the energy consumption is low, and the cost is reduced. At the same time, the positive and negative poles of the circuit breaker light-emitting element are short-circuited by the control circuit, so that the light-emitting element string is in the path, the normal operation of the light-emitting element string is ensured, and the entire light-emitting element string cannot be avoided due to the disconnection problem of the partial light-emitting element string. The problem of working properly.

In one embodiment, the light emitting element is a laser diode (LD). In another embodiment, the light emitting element is a light emitting diode (LED). In other embodiments, the above-mentioned light-emitting elements may also be other solid-state light-emitting elements, which are not limited in the present invention.

Based on the above embodiment, another embodiment of the present invention further provides a projector, which includes the light source device according to any of the above embodiments, which avoids the problem that the light source device of the conventional projector is disconnected due to partial light-emitting elements. The problem that caused it to not work properly.

The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but the scope of the invention is to be accorded

Claims

A light source device, characterized in that the light source device comprises:

The light source device according to claim 1, wherein the control circuit comprises: a controller, a plurality of voltage detecting circuits corresponding to the light emitting elements, and a plurality of one-to-one correspondence with the light emitting elements Switching circuit

The light source device according to claim 2, wherein the voltage detecting circuit comprises: a Zener diode and a photocoupler;

Wherein the photocoupler has a first input end, a second input end and an output end; the first input end is connected to the anode of the Zener diode, and the cathode of the Zener diode and the corresponding light-emitting element a positive input connection; the second input end is connected to a negative electrode of the corresponding light-emitting element; the output end is connected to the controller; when the light-emitting element is disconnected, the Zener diode is reverse-punched, so that The photocoupler is turned on, and the photocoupler is turned on to generate the feedback signal;

The light source device according to claim 2, wherein the switch circuit comprises: a relay having a third input end, a fourth input end, and a first control end;

The light source device according to claim 4, wherein the light emitting element string is connected to a first voltage source, and the first voltage source is configured to provide an operating current for the light emitting element;

Wherein the first voltage source is different from the second voltage source.

The light source device according to claim 2, wherein the switch circuit comprises: a switch tube, the switch tube having: a fifth input end, a sixth input end, and a second control end;

The light source device according to claim 6, wherein the switching tube is a MOS tube.

The light source device according to claim 1, wherein one end of the light-emitting element string is connected to a first port, and the first port is used to connect a first voltage source;

The light source device according to any one of claims 1 to 8, wherein the light emitting element is a laser diode or a light emitting diode.

A projector comprising: the light source device according to any one of claims 1-8.