WO2020052227A1

WO2020052227A1 - Projection apparatus, and white balance presetting method and realization method

Info

Publication number: WO2020052227A1
Application number: PCT/CN2019/081642
Authority: WO
Inventors: 余新; 胡飞; 李屹
Original assignee: 深圳光峰科技股份有限公司
Priority date: 2018-09-10
Filing date: 2019-04-08
Publication date: 2020-03-19
Also published as: CN110888293B; CN110888293A

Abstract

Disclosed is a projection apparatus (100), comprising: a light source (10) for emitting excitation light; a wavelength conversion device (20) having multiple color segments, wherein the color segments receive the excitation light in sequence with the rotation of the wavelength conversion device (20) so as to generate tri-phosphor light in a timing sequence, and the tri-phosphor light comprises fluorescence; a light source drive circuit (70) for providing a drive current for the light source; and a memory (80) for storing a one-to-one correlation between the brightness of fluorescence in each color, the light intensity of the excitation light and a current value of the drive current, wherein the light source drive circuit (70) determines a corresponding current value according to the brightness required by the fluorescence in each color and the one-to-one correlation, and provides a drive current for the light source (10) according to the determined current value, such that fluorescence in the color, which is generated from an excitation light passing through a corresponding color segment, has the required brightness, and the brightness of the fluorescence in each color, which is generated in the timing sequence, is adjustable to realize white balance. In addition, further disclosed are a white balance presetting method and realization method.

Description

Projection device, preset method and implementation method of white balance

Technical field

The present invention relates to the field of projection technology, and in particular, to a projection device.

Background technique

This section is intended to provide a background or context to the specific embodiments of the invention that are set forth in the claims. The description herein is not admitted to be prior art by inclusion in this section.

With the development of technology, more and more scenes need to use laser projection products. With the use of laser projection products, due to the influence of environmental cleanliness, temperature, and the operation of the device itself, the primary color light of the light source (such as red, green, and blue three primary color lights) will undergo a proportional change under the original white balance conditions As a result, the white balance changes, the color temperature shifts, and the image screen is discolored, which reduces the quality of the projected image.

Summary of the Invention

In view of this, the present invention provides a projection device capable of solving the above problems.

In addition, it is necessary to provide a preset method and implementation method of white balance applied to the projection device.

An embodiment of the present invention provides a projection device, including: a light source for emitting an excitation light; a wavelength conversion device having a plurality of color segments and rotating according to a preset period; The rotation of the wavelength conversion device sequentially receives the excitation light to generate at least three primary colors of light in sequence, the three primary colors of light include fluorescence; a light source driving circuit electrically connected to the light source, and the light source driving circuit is used for Providing a driving current to the light source; and a memory for storing a one-to-one correspondence between the brightness of each color of fluorescence, the intensity of the excitation light, and the current value of the driving current, wherein the light source driving circuit is based on each The brightness required for color fluorescence and the one-to-one correspondence determine the corresponding current value, and the driving current is provided to the light source according to the determined current value, so that the excitation light emitted by the light source passes through the corresponding wavelength conversion device. The fluorescence of that color produced after the color segment has the required brightness.

An embodiment of the present invention also provides a method for presetting a white balance, which is applied to a projection device. The projection device includes a light source, a wavelength conversion device, a light source driving circuit, and a memory. Excitation light, the wavelength conversion device has a plurality of color sections, and the color sections sequentially receive the excitation light as the wavelength conversion device rotates to generate at least three primary color lights in a time sequence, the three primary color lights The light source driving circuit is configured to provide a driving current to the light source, and the preset method of the white balance includes: pre-calibrating a relationship between a light intensity of the excitation light and a current value of the driving current; The relationship between the brightness of the fluorescence of each color and the intensity of the excitation light is calibrated in advance to obtain the fluorescence efficiency curve of the fluorescence of each color; according to the relationship between the intensity of the excitation light and the current value of the driving current and the fluorescence efficiency of each color of fluorescence The curve establishes a one-to-one correspondence between the brightness of the fluorescence of each color, the intensity of the excitation light, and the current value of the driving current in advance; and The relationship is stored in the memory, so that the light source driving circuit can determine a corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence relationship, and provide driving to the light source according to the determined current value. The current causes the fluorescence of the color generated by the excitation light emitted by the light source to pass through the corresponding color segment of the wavelength conversion device to have the required brightness.

An embodiment of the present invention also provides a method for realizing white balance, which is applied to a projection device. The projection device includes a light source, a wavelength conversion device, a light source driving circuit, and a memory. The light source is used to emit an excitation. Light, the wavelength conversion device has a plurality of color sections, and the color sections sequentially receive the excitation light to generate at least three primary color lights with the rotation of the wavelength conversion device, and the three primary light includes Fluorescence, the light source driving circuit is configured to provide a driving current to the light source, and the method for realizing the white balance includes: the light source driving circuit reads the brightness of each color of fluorescence stored in the memory, and the light of the excitation light A one-to-one correspondence between the strong and current values of the driving current; the light source driving circuit determines the corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence; and the light source driving circuit according to the The determined current value provides a driving current to the light source, so that the excitation light emitted by the light source passes through the corresponding wavelength conversion device. The fluorescence of that color produced after the color segment has the required brightness.

In the embodiment of the present invention, the light source driving circuit may set a current value of the driving current according to actual needs, so that the excitation light is incident on different color sections of the wavelength conversion device with preset different light intensities, Therefore, the brightness of the output fluorescence of each color can be adjusted, which is beneficial to achieve white balance. In addition, the relationship between the intensity of the excitation light and the current value of the driving current and the fluorescence efficiency curve of each color of fluorescence are calibrated in advance through experiments. A one-to-one correspondence between the brightness of the fluorescence of each color, the intensity of the excitation light, and the current value of the driving current is established in advance, and the light source driving circuit sets the current value of the driving current according to the one-to-one correspondence so that the wavelength The conversion device accurately outputs fluorescence of different brightness.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to explain the technical solutions of the embodiments / modes of the present invention more clearly, the drawings used in the description of the embodiments / modes are briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For a person of ordinary skill in the art, without drawing creative labor, other drawings may be obtained according to these drawings.

FIG. 1 is a schematic structural diagram of a projection device according to a preferred embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a wavelength conversion device of the projection apparatus shown in FIG. 1.

FIG. 3 is a relationship diagram between the light intensity of the excitation light and the current value of the driving current.

FIG. 4 is a graph showing the fluorescence efficiency curve of each color fluorescence.

FIG. 5 is a relationship diagram between a video frame and a sub-frame, and a sub-frame and a displayed color.

FIG. 6 is a flowchart of a method for presetting white balance according to a preferred embodiment of the present invention.

FIG. 7 is a flowchart of a method for implementing white balance according to a preferred embodiment of the present invention.

Explanation of main component symbols

光源 light source	1010
波长转换器件 Wavelength conversion device	2020
收集透镜 Collection lens	3030
分光镜Beamsplitter	4040
空间光调制器 Spatial light modulator	5050
投影镜头 Projection lens	6060
光源驱动电路Light source driving circuit	7070
存储器 Memory	8080
温度传感器 Temperature Sensor	8181
投影装置 Projection device	100100
第一颜色区段 First color segment	201201
第二颜色区段 Second color segment	202202
第三颜色区段 Third color segment	203203
第四颜色区段 Fourth color segment	204204
视频一帧Video one frame	A、A1A, A1
子帧Sub-frame	a、a0～a7a, a0 ～ a7

The following specific embodiments will further explain the present invention in conjunction with the above drawings.

detailed description

In order to more clearly understand the foregoing objects, features, and advantages of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

In the following description, many specific details are set forth in order to fully understand the present invention. The described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

Please refer to FIG. 1, a projection apparatus 100 provided by a preferred embodiment of the present invention includes a light source 10, a wavelength conversion device 20, a collection lens 30, a beam splitter 40, a spatial light modulator 50, a projection lens 60 and A light source driving circuit 70.

The light source 10 is used to emit an excitation light having a specific band of light. In this embodiment, the light source 10 is a blue light source (for example, a blue LED or a blue laser diode), and the excitation light emitted by the light source 10 is blue light. More specifically, the excitation light emitted by the light source 10 is a blue laser. Further, a scattering element (such as a scattering plate, not shown) may be disposed on the light source 10 to avoid the occurrence of laser speckle.

Please refer to FIG. 2 together. The wavelength conversion device 20 has a plurality of color segments and rotates according to a preset period. The color section sequentially receives the excitation light as the wavelength conversion device 20 rotates to generate at least three primary color lights in a time series. In this embodiment, the three primary colors of light include fluorescent light and scattered light. Correspondingly, the color section of the wavelength conversion device 20 includes a first color section 201, a second color section 202, and a third color section 203 in this order along the rotation direction of the wavelength conversion device 20. The first color section 201 and the second color section 202 include a first color phosphor and a second color phosphor, respectively. For example, the first color phosphor includes a red phosphor, which is receiving the The blue light is excited to generate red fluorescence; the second color phosphor includes a green phosphor, which is excited to generate green fluorescence after receiving the blue light. The third color section 203 is a light-transmitting area or a reflection area, which is used to transmit or reflect the blue light. A scattering material may be further disposed on the third color section 203 for decoherence of the blue light. The red, green, and blue scattered lights emitted in time sequence are the three primary colors of light. It should be noted that, in addition to the corresponding color phosphors, each color segment of the wavelength conversion device may further include an adhesive for encapsulating the fluorescence. The adhesive may be resin, silica gel, water glass, glass, or ceramic. Etc. Among them, when glass or ceramic is used as the packaging material of the phosphor, the prepared wavelength conversion is also called fluorescent glass or fluorescent ceramic. Specifically, the ceramic material may be selected from at least one of alumina, aluminum oxynitride, and magnesium aluminum spinel. The wavelength conversion device further includes a substrate for carrying a phosphor, and the substrate may be any combination of a reflective substrate and a transmissive substrate. According to different substrates, it can be divided into a transmissive fluorescent color wheel and a reflective fluorescent color wheel.

In this embodiment, the wavelength conversion device 20 may be a transmissive fluorescent color wheel, which is formed by coating different transparent phosphors on a transparent substrate. In another embodiment, the wavelength conversion device 20 may also be a reflective fluorescent color wheel, which is formed by coating a metal substrate or an optical reflective substrate with phosphors of different colors. In this embodiment, a focusing lens (not shown) and a collimating lens (not shown) may be further disposed between the light source 10 and the wavelength conversion device 20 in order. For the excitation light, the collimating lens is used to collimate the focused excitation light up to the wavelength conversion device 20.

The collection lens 30 is used to collect the three primary colors of light.

The beam splitter 40 is configured to reflect the three primary colors of light to the spatial light modulator 50. In this embodiment, the beam splitter 40 is a polarizing beam splitter (PBS, Polarizing Beam Splitter), and is configured to reflect incident light having a first polarization state among the three primary colors of light to the spatial light modulator 50.

The spatial light modulator 50 is configured to modulate incident light to obtain corresponding image light, and reflect the image light to the beam splitter 40. Therefore, the beam splitter 40 transmits the image light to the projection lens 60 to output a monochrome image, and the output monochrome image forms a color image through the integration effect of the human eye. In this embodiment, the spatial light modulator 50 modulates the incident light so that a first polarization state thereof is deflected by 90 degrees (that is, modulated to a second polarization state), and the modulated image light is modulated. Reflected to the beam splitter 40. The first polarization state and the second polarization state are perpendicular to each other. For example, if the first polarization state is an S polarization state, the second polarization state is a P polarization state. In this embodiment, the color segment of the wavelength conversion device 20 further includes a fourth color segment 204. The fourth color segment 204 includes a third color phosphor, such as the third color phosphor. The powder includes a yellow phosphor, which is excited to generate yellow fluorescence after receiving the blue light. The yellow fluorescence is used to compensate the brightness of the output image.

The light source driving circuit 70 is electrically connected to the light source 10. The light source driving circuit 70 is configured to provide a driving current to the light source 10 and set a current value of the driving current according to an actual need, thereby changing an intensity of the excitation light emitted by the light source 10. Therefore, after the excitation light passes through the wavelength conversion device 20, the brightness of each color of fluorescence (including red fluorescence, green fluorescence, and yellow fluorescence) generated in time sequence is adjustable, thereby achieving white balance at high brightness.

Please refer to FIG. 3, which is a relationship diagram between the light intensity of the excitation light and the current value of the driving current. It can be known from FIG. 3 that within a certain range, the light intensity of the excitation light is proportional to the current value of the driving current. As the current value of the driving current increases, the light intensity of the excitation light is linear. Increase. Therefore, the relationship between the intensity of the excitation light and the current value of the driving current can be calibrated in advance through experiments.

Please refer to FIG. 4, which is a graph showing the fluorescence efficiency curve of each color of fluorescence. As can be seen from FIG. 4, the overall relationship between the brightness of the fluorescence of each color and the intensity of the excitation light is nonlinear. Among them, when the intensity of the excitation light is in a lower range, the fluorescence conversion efficiency is higher, and the brightness of the red fluorescence, the green fluorescence, and the yellow fluorescence increases linearly; as the intensity of the excitation light continues to increase, as the phosphor reaches thermal saturation And light saturation, the fluorescence excitation efficiency gradually decreases, causing the brightness of red, green, and yellow fluorescence to increase non-linearly; as the intensity of the excitation light continues to increase, the brightness of red, green, and yellow fluorescence gradually decreases. Therefore, the fluorescence efficiency curve of each color fluorescence can be calibrated in advance through experiments.

Therefore, combining the relationship between the intensity of the reference excitation light and the current value of the driving current and the fluorescence efficiency curve of each color fluorescence, the brightness of the fluorescence of each color, the light intensity of the excitation light, and the current value of the driving current can be established in advance. There is a one-to-one correspondence between the two. In the one-to-one correspondence, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current. More specifically, a specific color fluorescence has a certain brightness L0, which corresponds to the light intensity of the excitation light M0, and the light intensity M0 of the excitation light corresponds to the current value I0 of the driving current; according to this one-to-one correspondence When the current value of the driving current is I0, the brightness of the fluorescence of the specific color is L0. The light source driving circuit 70 determines a corresponding current value according to the brightness required for each color of fluorescence and the one-to-one correspondence relationship, and provides a driving current to the light source 10 according to the determined current value, so that the light source 10 emits The fluorescence of the color generated after the excitation light passes through the corresponding color segment of the wavelength conversion device 20 has the required brightness, so that the brightness of the fluorescence of each color generated in time sequence can be adjusted to achieve white balance. The one-to-one correspondence is stored in a memory 80 of the projection apparatus 100.

Wherein, if the temperature value of the wavelength conversion device 20 is different, the fluorescence conversion efficiency under the excitation of the same intensity of the excitation light is usually different. Therefore, the fluorescence conversion efficiency needs to further refer to the temperature value of the wavelength conversion device 20. Therefore, in another In one embodiment, at this time, the fluorescence efficiency curves of the fluorescence of each color at different temperature values within a preset temperature range of the wavelength conversion device can be calibrated in advance through experiments, so that the brightness of each color of fluorescence, the intensity of the excitation light, A one-to-one correspondence between the temperature value of the wavelength conversion device and the current value of the driving current. In the one-to-one correspondence relationship, at a temperature value of the wavelength conversion device, each brightness of each color fluorescence corresponds to the excitation light. A light intensity and a current value of the driving current. The projection apparatus 100 further includes a temperature sensor 81. The temperature sensor 81 may be disposed adjacent to the wavelength conversion device 20 or disposed on the wavelength conversion device 20 to sense a temperature value of the wavelength conversion device 20. The light source driving circuit 70 obtains the temperature value sensed by the temperature sensor 81, and determines a corresponding current value according to the temperature value, the brightness required for the fluorescence of each color, and the one-to-one correspondence, and then according to the The determined current value provides a driving current to the light source 10 so as to dynamically achieve a projected white balance output at different ambient temperatures. In this embodiment, the preset temperature range is -30 ° C to 150 ° C. Preferably, the preset temperature range is -5 ° C to 100 ° C. More preferably, the preset temperature range is 5 ° C to 70 ° C. It should be noted that due to the difference in the position of the temperature sensor 81, even at different positions of the same wavelength conversion device 20, the temperature sensed by the temperature sensor 81 will be different; for example, at the excitation position of the fluorescent color wheel, the temperature It will be higher than other positions. At the same time, the proximity between the temperature sensor 81 and the wavelength conversion device 20 also affects the specific value range detected by the temperature sensor 81. Therefore, it can be understood that the temperature value of the wavelength conversion device 20 may be a temperature value within the range of the wavelength conversion device 20 and its vicinity.

In this embodiment, the spatial light modulator 50 is a silicon-based liquid crystal chip (ie, LCOS chip, Liquid Crystal), that is, the projection device 100 is a single-chip silicon-based liquid crystal projection device. When the sequential three-primary-color light corresponding to each frame image signal is incident on the LCoS chip, the LCoS chip modulates the incident light. Wherein, the LCOS chip is a driver chip manufactured by a semiconductor process, and then polished using a polishing technique on a transistor, and plated with aluminum or silver as a mirror to form a CMOS substrate. The CMOS substrate and glass containing a transparent electrode are then used. Liquid crystal molecules are poured into the substrate after the substrate is fully attached and obtained by packaging and testing. The LCOS chip may modulate the incident light and add spatial information to the incident light by controlling a polarization state. The spatial information may be a control signal voltage loaded on the LCOS chip. The control signal voltage directly controls a switching state of a thin film transistor, and then uses the thin film transistor to control a deflection state of the liquid crystal molecules, and the liquid crystal molecules have Obvious optical anisotropy can control the incident light to achieve the purpose of loading an image signal for the incident light. For example, the LCOS chip can modulate incident light with an S polarization state and load spatial information, and reflect the modulated image light with a P polarization state and load the spatial information to the beam splitter 40.

In particular, the modulation process of the incident light by the LCOS chip is completed within the duration of one frame, and each frame contains multiple subframes of equal duration, and the LCoS chip receives only a single within the duration of each subframe Color of incident light. Specifically, referring to FIG. 5, the video is composed of multiple video frames A. A video frame A1 contains only eight sub-frames a (ie, sub-frames a0 to a7 shown in the figure) of equal duration. Each sub-frame a can only display a single color. For example, sub-frames a0 to a2 are displayed in red. Sub-frames a3 to a4 are displayed in green, sub-frame a5 is displayed in blue, and sub-frames a6 to a7 are displayed in yellow.

With reference to FIG. 2, the wavelength conversion device 20 rotates n cycles (n ≧ 1, n is a natural number) corresponding to one frame A1 of the video, that is, the wavelength conversion device 20 can rotate n during the duration of the one frame A1 of the video. week. The color segments of the wavelength conversion device 20 correspond to subframes a0 to a7 in sequence during the rotation, and the colors of the fluorescence generated by the color segments of the wavelength conversion device 20 in sequence during the rotation are in accordance with the subframes a0 to a7. The displayed colors correspond. For example, the wavelength conversion device 20 is respectively provided as a first color section 201, a second color section 202, a third color section 203, and a fourth color section 204 along its circumferential direction. The first color section 201 occupies 3/8 of the area of the wavelength conversion device 20 and is used to excite red fluorescence, corresponding to subframes a0 to a2; the second color section occupies 1/4 of the area of the wavelength conversion device 20 and is used for For exciting green fluorescence, it corresponds to subframes a3 to a4; the third color segment occupies 1/8 of the area of the wavelength conversion device 20 and is used to transmit or reflect blue light, corresponding to subframe a5; the fourth color segment occupies The area of the wavelength conversion device 20 is 1/4 and is used to excite yellow fluorescence, corresponding to the subframes a6 to a7.

It can be understood that the time for the wavelength conversion device 20 to output a single color of fluorescence is limited (that is, the output time of a single color of fluorescence is an integer multiple of the duration of the subframe), which results in a smaller number of subframes (see FIG. 5 The frame A1 of the video shown in the figure includes only 8 sub-frames a0 to a7) and when high-brightness display is performed, the phenomenon of white balance imbalance tends to occur. Specifically, in the conventional projection device, since the current value of the driving current remains unchanged, the luminance ratio of each primary color in the output RGB three primary color light is fixed. Assume that the brightness ratio of each of the primary colors in the output RGB three primary colors is 25%: 60%: 15%, and the brightness ratio that reaches the white balance is 30%: 59%: 11%. This results in insufficient red fluorescence and blue Excessive shade. When the output time of a single-color fluorescence is limited, in order to maintain the white balance, the blue light cannot reach the maximum brightness, or when the blue light reaches the maximum brightness, it is difficult for the output image to achieve white balance.

In this embodiment, when the spatial light modulator is an LCOS chip, when the excitation light passes through the corresponding color section of the wavelength conversion device 20 and the fluorescence of the color has the required brightness, the corresponding Sub-frame a displays this color and has the required brightness, so that each frame achieves white balance. For example, when the wavelength conversion device 20 is rotated to the first color section (ie, the red phosphor region) to receive the excitation light, the current value of the driving current is increased to make the excited red fluorescence The brightness is increased, so that the brightness displayed in the sub-frames a0 to a2 is correspondingly enhanced. When the wavelength conversion device 20 is rotated to the third color section 203 (ie, the blue light reflection area) to receive the excitation light, it maintains or Reducing the current value of the driving current to maintain or reduce the brightness of the reflected blue light, so as to maintain the brightness displayed in the sub-frame a5 or reduce the brightness displayed in the sub-frame a5, so as to achieve white balance in one frame A1 of the video.

Referring to FIG. 6, a preferred embodiment of the present invention further provides a preset method for white balance applied to the projection apparatus 100. According to different requirements, the order of the steps of the preset method of white balance may be changed, and some steps may be omitted or combined. The preset method of the white balance includes:

Step S61: Pre-calibrate a relationship between a light intensity of the excitation light and a current value of the driving current.

Wherein, within a certain range, the light intensity of the excitation light is proportional to the current value of the driving current. As the current value of the driving current increases, the light intensity of the excitation light linearly increases.

In step S62, the relationship between the brightness of the fluorescence of each color and the light intensity of the excitation light is calibrated in advance to obtain a fluorescence efficiency curve of the fluorescence of each color.

Among them, there is a non-linear relationship between the brightness of the fluorescence of each color and the intensity of the excitation light. Among them, when the intensity of the excitation light is in a lower range, the fluorescence conversion efficiency is higher, and the brightness of the red fluorescence, the green fluorescence, and the yellow fluorescence increases linearly; as the intensity of the excitation light continues to increase, as the phosphor reaches thermal saturation And light saturation, the fluorescence excitation efficiency gradually decreases, causing the brightness of red, green, and yellow fluorescence to increase non-linearly; as the intensity of the excitation light continues to increase, the brightness of red, green, and yellow fluorescence gradually decreases.

Step S63: According to the relationship between the intensity of the excitation light and the current value of the driving current and the fluorescence efficiency curve of the fluorescence of each color, one of the brightness of the fluorescence of each color, the intensity of the excitation light, and the current value of the driving current is established in advance. A correspondence relationship. In the one-to-one correspondence, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current.

Step S64. The one-to-one correspondence is stored in the memory 80, so that the light source driving circuit 70 can determine the corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence, and according to The determined current value provides a driving current to the light source 10, so that the fluorescence of the color generated by the excitation light emitted by the light source 10 after passing through the corresponding color segment of the wavelength conversion device 20 has the required brightness, so that The brightness of the fluorescence of each color generated by the timing is adjustable to achieve white balance.

Wherein, if the temperature value of the wavelength conversion device 20 is different, the fluorescence conversion efficiency under the excitation of the same intensity of the excitation light is usually different. Therefore, the temperature conversion value of the wavelength conversion device 20 needs to be further referred to.

Therefore, in another embodiment, step S62 "pre-calibrating the relationship between the brightness of the fluorescence of each color and the intensity of the excitation light" is more specifically: pre-calibrating different temperature values within a preset temperature range of the wavelength conversion device The relationship between the brightness of the lower color fluorescence and the light intensity of the excitation light makes the one-to-one correspondence also include different temperature values within a preset temperature range of the wavelength conversion device. In the one-to-one correspondence relationship, at a temperature value of the wavelength conversion device, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current. In this case, the light source driving circuit 70 obtains the temperature value of the wavelength conversion device of the wavelength conversion device 20 sensed by the temperature sensor 81, and according to the temperature value, the brightness required for each color fluorescence And the one-to-one correspondence relationship determines a corresponding current value, and then provides a driving current to the light source 10 according to the determined current value, so as to dynamically realize a projected white balance output at different ambient temperatures. In this embodiment, the preset temperature range is -30 ° C to 150 ° C. Preferably, the preset temperature range is -5 ° C to 100 ° C. More preferably, the preset temperature range is 5 ° C to 70 ° C.

Referring to FIG. 7, a preferred embodiment of the present invention further provides a method for implementing white balance applied to the projection apparatus 100. According to different requirements, the order of steps of the method for implementing white balance may be changed, and some steps may be omitted or combined. The method for implementing the white balance includes:

Step S71: The light source driving circuit 70 reads the one-to-one correspondence between the brightness of each color of fluorescence, the intensity of the excitation light, and the current value of the driving current stored in the memory 80. In the one-to-one correspondence, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current.

Step S72: The light source driving circuit 70 determines a corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence.

Step S73: The light source driving circuit 70 provides a driving current to the light source 10 according to the determined current value, so that the excitation light emitted by the light source 10 passes through the corresponding color segment of the wavelength conversion device 20 and generates the color. The fluorescent light has the required brightness, so that the brightness of each color of the fluorescence generated in the time sequence can be adjusted to achieve white balance.

In summary, the light source driving circuit 70 can set the current value of the driving current according to actual needs, so that the excitation light is incident on different color sections of the wavelength conversion device 20 with different preset light intensities. Therefore, the brightness of the output fluorescence of each color can be adjusted, which is beneficial to achieve white balance. Furthermore, the relationship between the intensity of the excitation light and the current value of the driving current and the fluorescence efficiency curve of the fluorescence of each color are calibrated in advance through experiments to establish the brightness of the fluorescence of each color, the intensity of the excitation light, and the current of the driving current in advance. There is a one-to-one correspondence between the values, and the light source driving circuit 70 sets the current value of the driving current according to the one-to-one correspondence, so that the wavelength conversion device 20 accurately outputs fluorescence with different brightness. In addition, the fluorescence efficiency curve of each color fluorescence at different temperature values of the wavelength conversion device can be calibrated in advance. The light source driving circuit 70 looks up the table in the memory 80 according to the current temperature value of the wavelength conversion device 20 and the wavelength conversion device. The corresponding current value is determined to dynamically realize the projected white balance output under different ambient temperatures.

It is obvious to a person skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments are to be regarded as exemplary and non-limiting in every respect, and the scope of the present invention is defined by the appended claims rather than the above description, and therefore is intended to fall within the claims. All changes that come within the meaning and scope of equivalents are encompassed by the invention. Any reference signs in the claims should not be construed as limiting the claims involved. In addition, it is clear that the word "comprising" does not exclude other units or steps, and that the singular does not exclude the plural. Multiple devices stated in a device claim may also be implemented by the same device or system through software or hardware. Words such as first and second are used to indicate names, but not in any particular order.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not limited. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be Modifications or equivalent substitutions can be made without departing from the spirit and scope of the technical solution of the present invention.

Claims

A projection device includes:

A light source for emitting an excitation light;

A wavelength conversion device having a plurality of color segments and rotating according to a preset period, the color segments sequentially receiving the excitation light to generate at least three primary color lights with the rotation of the wavelength conversion device, The three primary colors of light include fluorescence;

A light source driving circuit electrically connected to the light source, the light source driving circuit being configured to provide a driving current to the light source; and

A memory for storing a one-to-one correspondence between the brightness of the fluorescence of each color, the intensity of the excitation light, and the current value of the driving current, wherein the light source driving circuit according to the brightness of each color of fluorescence and the The one-to-one correspondence determines the corresponding current value, and provides a driving current to the light source according to the determined current value, so that the excitation light emitted by the light source passes through the corresponding color segment of the wavelength conversion device. Fluorescence has the required brightness.
The projection device according to claim 1, wherein the one-to-one correspondence relationship further includes different temperature values within a preset temperature range of the wavelength conversion device, and in the one-to-one correspondence relationship, the wavelength conversion device At a temperature value, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current. The projection device further includes a temperature sensor for sensing the wavelength conversion. The temperature value of the device, the light source driving circuit obtains the temperature value sensed by the temperature sensor, and determines the corresponding current value according to the temperature value, the brightness required for each color fluorescence, and the one-to-one correspondence, and then A driving current is provided to the light source according to the determined current value.
The projection device according to claim 1, wherein the excitation light is blue light, and the color section of the wavelength conversion device includes a first color section, a A second color segment and a third color segment, the first color segment and the second color segment generating red fluorescence and green fluorescence, respectively, after receiving the blue light, the third color segment Is a light-transmitting area or a reflecting area, which is used to transmit or reflect the blue light.
The projection device according to claim 3, wherein the color section of the wavelength conversion device further comprises a fourth color section, and the fourth color section is excited after receiving the blue light and Produces yellow fluorescence.
The projection device according to claim 1, further comprising a spatial light modulator for modulating the three primary color lights to obtain corresponding image light.
The projection device according to claim 5, wherein the spatial light modulator is an LCoS chip, and when the sequential three primary color lights corresponding to the image signal of each frame are incident on the LCoS chip, the LCoS chip is The incident light is modulated within the duration of one frame, and each frame includes multiple subframes of equal duration. The LCoS chip receives only a single color of incident light within the duration of each subframe.
The projection device according to claim 5, further comprising a collection lens and a beam splitter disposed between the wavelength conversion device and the spatial light modulator, and the collection lens is used for collecting the Three-primary-color light, the beam splitter is configured to reflect the three-primary-color light to the spatial light modulator.
A method for presetting white balance is applied to a projection device. The projection device includes a light source, a wavelength conversion device, a light source driving circuit, and a memory. The light source is used to emit an excitation light. The wavelength The conversion device has a plurality of color sections, and the color sections sequentially receive the excitation light to generate at least three primary color lights in sequence with the rotation of the wavelength conversion device, the three primary color lights include fluorescence, and the light source The driving circuit is configured to provide a driving current to the light source. The preset method of the white balance includes:

Pre-calibrating a relationship between a light intensity of the excitation light and a current value of the driving current;

The relationship between the brightness of the fluorescence of each color and the intensity of the excitation light is calibrated in advance to obtain the fluorescence efficiency curve of the fluorescence of each color;

According to the relationship between the intensity of the excitation light and the current value of the driving current and the fluorescence efficiency curve of the fluorescence of each color, a one-to-one correspondence between the brightness of the fluorescence of each color, the intensity of the excitation light, and the current value of the driving current is established in advance ;as well as

Storing the one-to-one correspondence in the memory, so that the light source driving circuit can determine a corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence, and according to the determined current value A driving current is provided to the light source, so that the fluorescence of the color generated after the excitation light emitted by the light source passes through the corresponding color segment of the wavelength conversion device has a desired brightness.
The method for presetting the white balance according to claim 8, wherein the relationship between the pre-calibration brightness of the fluorescence of each color and the intensity of the excitation light is: pre-calibrating a preset temperature range of the wavelength conversion device The relationship between the brightness of the fluorescence of each color and the intensity of the excitation light at different temperature values, so that the one-to-one correspondence also includes different temperature values within the preset temperature range of the wavelength conversion device, and the one-to-one correspondence In a temperature value of the wavelength conversion device, each brightness of each color fluorescence corresponds to a light intensity of the excitation light and a current value of the driving current, so that the light source driving circuit can be based on the wavelength of the wavelength conversion device. The temperature value of the conversion device, the brightness required for each color of fluorescence, and the one-to-one correspondence determine a corresponding current value, and then provide a driving current to the light source according to the determined current value.
A method for realizing white balance is applied to a projection device. The projection device includes a light source, a wavelength conversion device, a light source driving circuit, and a memory. The light source is used to emit an excitation light, and the wavelength is converted. The device has a plurality of color sections, and the color sections sequentially receive the excitation light to generate at least three primary color lights in sequence with the rotation of the wavelength conversion device, the three primary color lights include fluorescence, and the light source drives The circuit is configured to provide a driving current to the light source, and the method for implementing the white balance includes:

The light source driving circuit reads the one-to-one correspondence between the brightness of each color of fluorescence, the intensity of the excitation light, and the current value of the driving current stored in the memory;

The light source driving circuit determines a corresponding current value according to the brightness required for each color fluorescence and the one-to-one correspondence; and

The light source driving circuit provides a driving current to the light source according to the determined current value, so that the fluorescence of the color generated by the excitation light emitted by the light source after passing through the corresponding color segment of the wavelength conversion device has the required brightness .