Temperature measuring device and projection ray machine

Abstract

The utility model provides a temperature measuring device, which comprises a shell comprising a light-transmitting first connecting wall and a heat-insulating second connecting wall, and the first connecting wall and the second connecting wall are enclosed to form a sealed cavity; and the radiant energy absorber is located in the sealing cavity and comprises a temperature sensor arranged towards the first connecting wall, and the temperature sensor is used for detecting the temperature value of the rotating heat source outside the sealing cavity in real time. According to the temperature measuring device, the temperature value of the rotating heat source is indirectly detected through the radiant energy absorber in the sealed cavity, on one hand, the light-transmitting first connecting wall can effectively reduce heat radiation propagation loss of the rotating heat source, on the other hand, the heat-insulating second connecting wall can improve the conversion rate of heat radiation, and therefore the temperature value detection accuracy can be improved; when the temperature measuring device is applied to the projection ray machine, the radiant energy absorber can accurately measure the surface temperature of a rotating heat source (color wheel) in the projection ray machine. The utility model further provides a projection ray machine.

Description

Technical Field

[0001] The present application relates to the field of temperature detection technology, and in particular to a temperature measuring device and a projection optical machine including the temperature measuring device. Background Art

[0002] The color wheel, composed of photoluminescent phosphor and silicone, is a key component of laser projection display systems. As the most crucial component of the color wheel, the phosphor's luminous efficiency decays exponentially as its temperature rises. Therefore, controlling the color wheel's surface temperature within a reasonable range is crucial for ensuring its high reliability and efficiency, and for promoting the development of high-power, high-brightness laser projection display systems. However, due to the high rotation speed of the color wheel, established contact temperature measurement solutions are not feasible. Furthermore, the small size of the optical machine housing the color wheel makes conventional non-contact temperature measurement difficult to implement. Therefore, an effective and feasible solution is urgently needed to address the difficulty of measuring the surface temperature of rotating heat sources, such as color wheels.

[0003] To address the problem of difficulty in measuring the surface temperature of a rotating heat source, the existing technical solutions mainly include: 1. Based on the contact testing method, thermocouple sensors or thermistors are arranged at measuring points in the vicinity of a rotating heat source, such as a color wheel, to obtain the temperature of the relevant measuring points, and further use the mathematical relationship between the measuring point temperature, the heat source surface temperature, the thermal resistance from the measuring point to the rotating heat source surface, and the rotating heat source power to obtain the temperature of the rotating heat source surface; 2. Use an infrared thermometer to obtain the temperature of the rotating heat source surface; 3. Based on magnetic nanoparticles, the temperature signal is converted into a magnetic field signal to finally obtain the temperature of the rotating heat source surface.

[0004] However, under the first solution, since the thermal resistance from the measuring point to the surface of the rotating heat source can only be roughly estimated, the credibility of the result is low; the second solution has too many influencing factors, the accuracy and precision are poor, and the volume of the optical machine needs to be increased, making it difficult to apply in engineering; the third solution cannot be applied to optical machine modules with electromagnetic shielding characteristics. Utility Model Content

[0005] In a first aspect, the present application provides a temperature measuring device, comprising: a shell, comprising a light-transmissive first connecting wall and a heat-insulating second connecting wall, wherein the first connecting wall and the second connecting wall enclose a sealed cavity; and a radiation energy absorber, located in the sealed cavity, comprising a temperature sensor arranged toward the first connecting wall, wherein the temperature sensor is used to detect the temperature value of a rotating heat source outside the sealed cavity in real time.

[0006] In at least one embodiment of the present application, the sealed cavity is in a vacuum state.

[0007] In at least one embodiment of the present application, the second connecting wall is made of a heat-insulating material or is coated with a heat-insulating material layer.

[0008] In at least one embodiment of the present application, the second connecting wall is made of glass or ceramic.

[0009] In at least one embodiment of the present application, the radiation energy absorber further includes a main body, the main body including a mounting surface on which the plurality of temperature sensors are disposed, and a vertical distance between the mounting surface and the first connecting wall is less than 0.5 mm.

[0010] In at least one embodiment of the present application, the main body is made of a thermally inert material or is coated with a heat-resistant material layer.

[0011] A second aspect of the present application provides a projection light engine, comprising: a laser source for emitting a light source laser; a color wheel located in the optical path of the light source laser, wherein the color wheel rotates around an axis so that the light source laser excites a fluorescent material on the color wheel to generate fluorescence, and the fluorescence is used to display a projected image; a temperature measuring device such as any of the above-mentioned ones, located on a side of the color wheel away from the laser source and spaced apart from the color wheel, the first connecting wall is arranged toward the color wheel, and the multiple temperature sensors are used to detect the temperature of the color wheel surface in real time.

[0012] In at least one embodiment of the present application, the radiation energy absorber further includes a main body, and the main body includes a mounting surface on which the multiple temperature sensors are disposed: the minimum vertical distance between the color wheel and the first connecting wall is equal to the minimum vertical distance between the mounting surface and the first connecting wall.

[0013] In at least one embodiment of the present application, the minimum vertical distance between the inner surface of the first connecting wall and the mounting surface is L1, and the minimum vertical distance between the color wheel and the outer surface of the first connecting wall is L2, where L1+L2<1 mm.

[0014] In at least one embodiment of the present application, the projection light engine includes a housing, the housing forms a closed space, the color wheel and the temperature measuring device are located in the closed space, and a partial area of ​​the housing and the shell together enclose the sealed cavity.

[0015] The aforementioned temperature measurement device and the projection light engine incorporating it indirectly measure the temperature of a rotating heat source using a temperature sensor in a radiation energy absorber within a sealed cavity. The transparent first connecting wall effectively reduces the loss of thermal radiation from the rotating heat source as it propagates into the sealed cavity. Furthermore, the thermally insulating second connecting wall reduces outward heat dissipation, ensuring that as much of the thermal radiation as possible is converted into temperature. By reducing the propagation loss of thermal radiation and improving the efficiency of thermal radiation conversion, the temperature measurement device improves the accuracy of the indirect temperature measurement performed by the radiation energy absorber. Therefore, when the aforementioned temperature measurement device is used in a projection light engine, the radiation energy absorber can accurately measure the surface temperature (laser irradiation surface) of the rotating heat source (color wheel) within the projection light engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional structural diagram of the projection optical engine according to an embodiment of the present application.

[0017] Figure 2 for Figure 1 A partial enlarged view of .

[0018] Figure 3 This is a structural diagram of a temperature measurement device in at least one modified embodiment of the present application.

[0019] Description of main component symbols

[0020] Projection light machine: 100

[0021] Shell: 10

[0022] Enclosed space: 20

[0023] Projection optical system: 30

[0024] Laser source: 31

[0025] Color wheel: 32

[0026] Base: 321

[0027] Fluorescent material layer: 322

[0028] Temperature measuring device: 40

[0029] Housing: 41

[0030] Sealed cavity: 411

[0031] First connecting wall: 412

[0032] Inner surface: 4121

[0033] Outer surface: 4122

[0034] Second connecting wall: 413

[0035] Radiant energy absorber: 42

[0036] Main body: 421

[0037] Mounting surface: 4211

[0038] Temperature sensor: 422

[0039] Rubber: 43

[0040] Low thermal conductivity material layer: 44

[0041] Axis:L.

[0042] The following specific implementation methods will further illustrate this application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0043] Embodiments of the present application provide a temperature measurement device and a projection engine incorporating the same. This temperature measurement device uses a radiation energy absorber within a sealed cavity to indirectly detect the temperature of a rotating heat source outside the sealed cavity. This effectively improves temperature detection accuracy by reducing heat radiation loss and increasing heat radiation conversion efficiency. Therefore, when the temperature measurement device is applied to a projection engine, the radiation energy absorber can accurately measure the surface temperature of the rotating heat source within the projection engine.

[0044] See also Figure 1 The projector 100 of the present application includes a housing 10. The housing 10 encloses a closed space 20. The projector 100 also includes a projection light system 30. The projection light system 30 is configured to emit projection light. The projection light can be transmitted through the closed space 20 and projected onto an imaging medium (e.g., a projection screen or a wall) to produce a projected image.

[0045] In this embodiment, the projection optical system 30 generates projection light based on a rotating color wheel. The projection optical system 30 includes a laser source 31 and a color wheel 32, which are spaced apart. The laser source 31 may include one or more lasers for emitting light source laser light. The color wheel 32 has a base 321 and a fluorescent material layer 322 supported on the surface of the base 321. The fluorescent material layer 322 of the color wheel 32 is disposed toward a port for emitting light source laser light from the laser source 31. In this embodiment, the laser source 31 is located outside the enclosed space 20, and the color wheel 32 is located within the enclosed space 20. In other embodiments of the present application, both the laser source 31 and the color wheel 32 may be located within the enclosed space 20.

[0046] The color wheel 32 can rotate about an axis L perpendicular to the base 321. When the laser source 31 is turned on and the color wheel 32 is rotated, the laser light from the source is projected onto different locations on the fluorescent material layer 322 as the color wheel 32 rotates. Different locations on the fluorescent material layer 322 have different fluorescent materials. Therefore, as the color wheel 32 rotates, the laser light from the source can excite different fluorescent materials in different time periods, producing fluorescent light of different colors.

[0047] In this embodiment, the color wheel 32 is a reflective color wheel. That is, unused laser light and stimulated fluorescent light that enter the color wheel 32 are reflected by the color wheel. In this embodiment, the laser light and fluorescent light emitted from the color wheel 32 are used to form the aforementioned projection light.

[0048] During the rotation of the color wheel 32, the laser from the light source continuously excites the fluorescent material, generating a large amount of heat. The luminous efficiency of the fluorescent material layer 322 decays exponentially as the temperature of the fluorescent material rises. Therefore, it is necessary to control the surface temperature of the color wheel 32 within a reasonable range during operation to ensure high reliability and high efficiency. This is particularly applicable to high-power, high-brightness laser projection display systems. However, due to the high-speed rotation of the color wheel 32, traditional contact temperature measurement solutions are not feasible. On the other hand, due to the limited volume of the enclosed space 20 in the projection light engine 100, it is also difficult to apply traditional non-contact temperature measurement solutions.

[0049] Therefore, the projection light engine 100 of the present embodiment further includes a temperature measurement device 40 for real-time monitoring of the surface temperature of the color wheel 32. In this embodiment, the temperature measurement device 40 is located on the side of the color wheel 32 facing away from the laser source 31 and is spaced apart from the color wheel. In other words, the color wheel 32 is located between the laser source 31 and the temperature measurement device 40.

[0050] Please also refer to Figure 1 and Figure 2 The temperature measuring device 40 includes a shell 41 and a radiation energy absorber 42. The shell 41 forms a sealed cavity 411, and the radiation energy absorber 42 is located in the sealed cavity 411. By arranging the radiation energy absorber 42 in the sealed cavity 411, the radiation energy absorber 42 can detect the temperature of the surface of the color wheel 32 by indirect temperature measurement. The shell 41 can effectively isolate the vortex caused by the rotation of the color wheel 32, so that the radiation energy absorber 42 can accurately detect the temperature of the surface of the color wheel 32. In this embodiment, the sealed cavity 411 is in a vacuum state. The "temperature on the surface of the color wheel 32" in this embodiment refers to the temperature at the position on the fluorescent material layer 322 of the color wheel 32 that is irradiated by the laser from the light source.

[0051] In this embodiment, the housing 41 includes a first connecting wall 412 and a second connecting wall 413. The first connecting wall 412, the second connecting wall 413 and the housing 10 of the projection light engine 100 are fixedly connected in sequence to form the sealed cavity 411. In this embodiment, the temperature measuring device 40 also includes a high-temperature resistant rubber 43, which is disposed between the first connecting wall 412, the second connecting wall 413 and the housing 10 to seal the sealed cavity 411. Figure 3 In at least one modified embodiment of the present application, the first connecting wall 412 and the second connecting wall 413 are fixedly connected to each other to enclose the sealed cavity 411. In this embodiment, the sealed cavity 411 is formed by reusing the housing 10 of the projection light engine 100, which helps to simplify the overall structure of the projection light engine 100 and fully utilize the internal components of the projection light engine 100.

[0052] Please refer to Figure 1 In this embodiment, the first connecting wall 412 is made of a highly translucent material (e.g., high-temperature and high-pressure-resistant glass). This helps reduce the loss of radiant energy generated by the color wheel 32 during transmission to the radiant energy absorber 42. The second connecting wall 413 is made of a thermally insulating material (e.g., glass, ceramic, etc.) with a smooth surface, which helps reduce heat exchange between the inside and outside of the housing 41 and prevents heat loss from radiating out of the sealed cavity 411. In this embodiment, the outer surface of the second connecting wall 413 is also coated with a thermally insulating material layer 44, which further reduces heat loss from radiating out of the sealed cavity 411.

[0053] In other embodiments of the present application, the second connecting wall 413 may be entirely made of a heat-insulating material without being coated with a heat-insulating material layer, or the second connecting wall 413 may be entirely made of a non-heat-insulating material with a heat-insulating material layer 44 coated on its surface. In this embodiment, the second connecting wall 413 is made of a heat-insulating material and coated with a heat-insulating material layer 44, which helps to improve the heat insulation effect.

[0054] In this embodiment, the radiation energy absorber 42 includes a main body 421 and multiple temperature sensors 422 disposed on the main body 421. Each temperature sensor 422 is distributed on the side of the main body 421 facing the color wheel 32. Each temperature sensor 422 serves as multiple temperature measurement points for the radiation energy absorber 42. The main body 421 is constructed of a thermally inert material (such as metal, ceramic, or oxide), or coated with a heat-resistant material layer (for example, a uniform layer of high-temperature-resistant black paint). By configuring the main body 421 with a thermally inert material or coating it with a heat-resistant material layer, heat from the main body 421 is less likely to radiate outward, retaining as much heat as possible to be converted into a temperature value by the temperature sensors 422 on the main body 421. The temperature sensor 422 can be a thermocouple sensor, a thermistor, or the like, capable of sensing temperature and converting it into an electrical signal for output. In this embodiment, the electrical signal generated by the temperature sensor 422 can be transmitted to an external control structure (such as a control chip in the projection light engine 100) or a smart terminal connected to the projection light engine 100, for example, by burying wires on the main body 421 or the shell 41.

[0055] In this embodiment, the first connecting wall 412 has an inner surface 4121 and an outer surface 4122 that are parallel to the color wheel 32. The main body 421 of the radiation energy absorber 42 has a mounting surface 4211 for setting temperature measurement points, and the mounting surface 4211 is parallel to the color wheel 32. There is a minimum vertical distance L1 between the mounting surface 4211 and the inner surface 4121, and there is a minimum vertical distance L2 between the outer surface 4122 and the color wheel 32. In this embodiment, L1 = L2, L1 < 0.5 mm, that is, L1 + L2 < 1 mm. In this way, the distance between each temperature measurement point of the radiation energy absorber 42 and the color wheel 32 is relatively small, which can effectively reduce the transmission loss of thermal radiation generated by the color wheel 32 and help improve the detection accuracy of the temperature measurement points.

[0056] In this embodiment, based on the principles of thermal radiation and heat conduction, a vacuum sealed cavity 411 is provided to accommodate the radiation energy absorber 42. On this basis, a highly transparent first connecting wall 412 and a heat-insulating second connecting wall 413, a heat-resistant body 421 of the radiation energy absorber 42, and L1+L2<1mm and L1=L2 are provided, so that the temperature values ​​detected at each temperature measuring point on the radiation energy absorber 42 have a specific mapping relationship with the temperature value at the position on the surface of the color wheel 32 irradiated by the laser light source.

[0057] In this way, the detected temperature value can be obtained by analyzing the electrical signal detected at each temperature measuring point on the radiation energy absorber 42. By performing angle correction on the detected temperature value, the temperature value at the position on the surface of the color wheel 32 irradiated by the laser from the light source (i.e., the temperature value at each point on the laser irradiation surface of the color wheel 32) can be obtained by reverse calculation based on the above-mentioned specific mapping relationship.

[0058] In at least one embodiment of the present application, the above-mentioned specific mapping relationship is obtained by:

[0059] Step 1: Keep the color wheel still;

[0060] The second step is to rotate the light source laser along the axis of the color wheel so that the laser moves relative to the color wheel at the same speed;

[0061] The third step is to use a fan to create a vortex similar to the rotation of a color wheel;

[0062] Step 4: Set multiple temperature measurement points at multiple relevant locations on the laser irradiation surface of the color wheel (the surface directly irradiated by the laser light source) on the radiation energy absorber, and obtain the temperature of each of the relevant locations and each temperature measurement point;

[0063] The fifth step is to change the intensity of the light source laser to obtain the temperature of each relevant position and each temperature measurement point under different laser intensities;

[0064] The sixth step is to obtain the relationship between the temperature of the laser irradiation surface and the temperature of the temperature measuring point on the radiation energy absorber (that is, the above-mentioned mapping relationship).

[0065] The temperature measurement device 40 of the present embodiment indirectly measures the temperature of a rotating heat source (color wheel 32) via a temperature sensor 422 in a radiation energy absorber 42 within a sealed cavity 411. The provision of a light-transmitting first connecting wall 412 effectively reduces heat loss during the propagation of thermal radiation from the rotating heat source into the sealed cavity 411. Furthermore, the provision of a thermally insulating second connecting wall 413 prevents heat within the sealed cavity 411 from dissipating outward, allowing the temperature sensor 422 to convert as much thermal radiation as possible into a temperature value. In other words, by reducing thermal radiation propagation losses and improving thermal radiation conversion efficiency, the temperature measurement device 40 of the present embodiment improves the sensing accuracy of the radiation energy absorber 42 in indirect temperature measurement, making it effectively applicable for indirect temperature measurement of rotating heat source surfaces.

[0066] Furthermore, the gap (L1 + L2) between the radiation energy absorber 42 and the color wheel 32 is extremely small, allowing the surface temperature of the radiation energy absorber 42 to map to the surface temperature of the color wheel 32 based on the principles of thermal radiation and heat conduction. By fitting and correcting the temperature values ​​measured by the radiation energy absorber 42, the temperature values ​​at each point on the laser-irradiated surface of the color wheel 32 can be accurately determined, effectively resolving the difficulty in measuring the surface temperature of a rotating heat source.

[0067] Furthermore, in the optical projection engine 100 of the present embodiment, both the laser source 31 and the color wheel 32 generate heat during operation. To minimize the influence of other heat sources (the laser source 31) when measuring the surface temperature of the color wheel 32, the laser source 31 is positioned outside the enclosed space 20. Therefore, the positioning relationship between the laser source 31 and the color wheel 32 in this embodiment further enhances the accuracy of temperature measurement.

[0068] In this embodiment, by providing a temperature measuring device 40 in the projector light engine 100 to detect the temperature of each point on the laser irradiation surface of the color wheel 32 in real time, an alarm can be promptly issued to stop the projector light engine 100 when a temperature abnormality is detected, or the driving current of the laser source 31 can be adjusted according to the real-time temperature value feedback to adjust the luminous power of the laser source 31, so that the temperature of the color wheel 32 is always maintained within a preset temperature range, which is beneficial to improving the light conversion efficiency of the color wheel in the projector light engine 100 and ensuring the stable operation of the projector light engine 100.

[0069] In other embodiments of the present application, the temperature measuring device 40 can be applied to other types of equipment for real-time detection of other types of rotating heat sources besides the rotating color wheel, and can also achieve real-time and accurate detection of the temperature of the rotating heat source.

[0070] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not used to limit the present application. As long as they are within the spirit of the present application, appropriate changes and modifications to the above embodiments are within the scope of protection claimed in the present application.

Claims

1. A temperature measuring device, characterized in that: include: The housing comprises a light-transmitting first connecting wall and a heat-insulating second connecting wall, wherein the first connecting wall and the second connecting wall enclose a sealed cavity; as well as The radiation energy absorber is located in the sealed cavity and includes a temperature sensor arranged toward the first connecting wall. The temperature sensor is used to detect the temperature value of the rotating heat source outside the sealed cavity in real time.

2. The temperature measuring device according to claim 1, wherein The sealed cavity is in a vacuum state.

3. The temperature measuring device according to claim 2, wherein: The second connecting wall is made of a heat-insulating material or is coated with a heat-insulating material layer.

4. The temperature measuring device according to claim 3, wherein: The second connecting wall is made of glass or ceramic.

5. The temperature measuring device according to claim 2, wherein: The radiant energy absorber further includes a main body, wherein the main body includes a mounting surface provided with the temperature sensor, and a vertical distance between the mounting surface and the first connecting wall is less than 0.5 mm.

6. The temperature measuring device according to claim 5, wherein: The main body is made of thermally inert material or is coated with a heat-resistant material layer.

7. A projection light machine, characterized in that: include: A laser source, used for emitting a light source laser; A color wheel is located in the optical path of the light source laser, and the color wheel rotates around an axis so that the light source laser excites the fluorescent material on the color wheel to generate fluorescence, and the fluorescence is used to display the projected image; The temperature measuring device according to any one of claims 1 to 6 is located on a side of the color wheel away from the laser source and spaced apart from the color wheel, the first connecting wall is arranged toward the color wheel, and the multiple temperature sensors are used to detect the temperature of the color wheel surface in real time.

8. The optical projection machine according to claim 7, wherein: When the radiant energy absorber further comprises a main body, wherein the main body comprises a mounting surface provided with the plurality of temperature sensors: A minimum vertical distance between the color wheel and the first connecting wall is equal to a minimum vertical distance between the mounting surface and the first connecting wall.

9. The optical projection machine according to claim 8, wherein: The minimum vertical distance between the inner surface of the first connecting wall and the mounting surface is L1, and the minimum vertical distance between the color wheel and the outer surface of the first connecting wall is L2, where L1+L2<1 mm.

10. The optical projection machine according to claim 7, wherein: The projection light engine includes a housing, the housing forms a closed space, the color wheel and the temperature measuring device are located in the closed space, and a partial area of ​​the housing and the shell are enclosed together to form the sealed cavity.

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