JP6569243B2 - Light source device, projector, and color balance adjustment method - Google Patents

Description

  The present invention relates to a light source device, a projector, and a color balance adjustment method.

  In recent years, light source devices using phosphors are used in projectors. As such a light source device, there is known a device that generates fluorescent light by irradiating a phosphor layer with excitation light, and generates white illumination light by synthesizing the fluorescence and the excitation light (for example, patents). Reference 1).

JP 2012-3923 A

  However, in the above prior art, it has been difficult to easily adjust the white balance of illumination light that has changed due to some cause such as deterioration of the excitation light source over time.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a light source device capable of easily adjusting the white balance of illumination light. Another object of one aspect of the present invention is to provide a projector including this type of light source device. Another object of one embodiment of the present invention is to provide a color balance adjustment method that can easily adjust the white balance of illumination light.

According to the first aspect of the present invention, a light emitting element, a collimating optical system on which excitation light emitted from the light emitting element is incident, and a condensing optical system on which the excitation light emitted from the collimating optical system is incident A phosphor layer that emits a part of the excitation light incident from the condensing optical system and fluorescence as illumination light, a color balance detection device that measures a color balance of the illumination light, and the color balance detection Based on the measurement result obtained by the apparatus, the size of the spot diameter of the excitation light formed on the phosphor layer is adjusted by adjusting the distance between the condensing optical system and the phosphor layer. A distance adjusting device that changes the moving mechanism, and the distance adjusting device controls the moving mechanism based on a detection result of the color balance detecting device and a moving mechanism that moves the condensing optical system with respect to the phosphor layer. Control device to The control device compares the reference value stored in advance with the detection value of the color balance detection device, and if the difference between the reference value and the detection value exceeds a predetermined threshold, the control value is The distance adjusting device controls the moving mechanism so as to approach a reference value, and the focusing optical system reduces the spot diameter of the excitation light when the fluorescence intensity is larger than the excitation light intensity. And the phosphor layer is adjusted so that the spot diameter of the excitation light is increased when the fluorescence intensity is smaller than the excitation light intensity. A light source device for adjusting the distance is provided.

  The light source device according to the first aspect is formed on the phosphor layer by adjusting the distance between the condensing optical system and the phosphor layer when the white balance of the illumination light changes for some reason. The amount of light per unit area of the light spot can be changed. Thereby, the light quantity balance between a part of light incident from the condensing optical system in the illumination light and the fluorescence changes. Therefore, the color balance (white balance) of illumination light can be easily adjusted.

In the light source device, in the initial state, the distance adjusting device preferably adjusts the distance so that the condensing optical system is in a defocused state.
According to this configuration, since the condensing optical system is in the defocused state in the initial state, the size of the light formed on the phosphor layer can be increased or decreased. Therefore, the adjustment range of the color balance of illumination light can be expanded.

  According to the second aspect of the present invention, the light source device according to the first aspect, a light modulation device that forms image light by modulating illumination light from the light source device according to image information, and the image light And a projection optical system for projecting.

  According to the projector according to the second aspect, since the light source device according to the first aspect is provided, the projector can perform a bright display with excellent image quality.

According to the third aspect of the present invention, a light emitting element, a collimating optical system on which excitation light emitted from the light emitting element is incident, and a condensing optical system on which the excitation light emitted from the collimating optical system is incident A color balance adjustment method for a light source device comprising: a part of the excitation light incident from the condensing optical system; and a phosphor layer that emits fluorescence as illumination light, the color of the illumination light and color balance measuring step of measuring the balance, based on the measurement result obtained by the color balance measuring step, the phosphor layer by adjusting the distance between the phosphor layer and the light converging optical system An adjustment step of changing the spot diameter of the excitation light formed in the step, wherein the adjustment step compares the reference value stored in advance with the measurement value obtained in the color balance measurement step, The reference value and the measured value If the difference exceeds a predetermined threshold value, the measured value by moving the focusing optical system so as to approach the reference value for the phosphor layer, if the intensity of the fluorescence is greater than the intensity of the excitation light When the distance between the condensing optical system and the phosphor layer is adjusted so that the spot diameter of the excitation light is small, and the intensity of the fluorescence is smaller than the intensity of the excitation light, the spot diameter of the excitation light There is provided a color balance adjustment method for adjusting the distance between the condensing optical system and the phosphor layer so as to be large .

  According to the color balance adjusting method according to the third aspect, when the white balance of the illumination light changes due to some cause, the distance between the condensing optical system and the phosphor layer is adjusted, thereby The amount of light per unit area of the light spot formed can be changed. Thereby, the light quantity balance between a part of light incident from the condensing optical system in the illumination light and the fluorescence changes. Therefore, the color balance (white balance) of illumination light can be easily adjusted.

In the color balance adjustment method, in the initial state before starting the color balance adjustment, the distance is preferably adjusted so that the condensing optical system is in a defocused state.
According to this configuration, since the condensing optical system is in the defocused state in the initial state, the size of the light formed on the phosphor layer can be increased or decreased. Therefore, the adjustment range of the color balance of illumination light can be expanded.

FIG. 2 is a diagram illustrating a schematic configuration of a projector. The figure which shows schematic structure of a light source device. (A), (b) is a block diagram which shows an example of a phosphor wheel. The flowchart figure which adjusts the deviation | shift of white balance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

FIG. 1 is a diagram illustrating a schematic configuration of a projector according to the present embodiment.
As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on a screen SCR. The projector 1 uses three light modulation devices corresponding to each color light of red light LR, green light LG, and blue light LB. The projector 1 uses a semiconductor laser that can obtain light with high luminance and high output as the light source of the light source device 2.

  The projector 1 includes a light source device 2, a color separation optical system 3, a red light modulation device 4R, a green light modulation device 4G, a blue light modulation device 4B, a combining optical system 5, and a projection. And an optical system 6.

  The light source device 2 emits white illumination light WL toward the color separation optical system 3. As the light source device 2, a light source device according to one embodiment of the present invention to be described later is used.

  The color separation optical system 3 separates the white illumination light WL emitted from the light source device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflection mirror 8a, a second reflection mirror 8b, a third reflection mirror 8c, and a first A relay lens 9a and a second relay lens 9b are provided.

  The first dichroic mirror 7a separates the illumination light WL emitted from the light source device 2 into red light LR, green light LG, and blue light LB. The first dichroic mirror 7a transmits the red light LR and reflects the green light LG and the blue light LB. The second dichroic mirror 7b separates the light reflected by the first dichroic mirror 7a into green light LG and blue light LB. The second dichroic mirror 7b reflects the green light LG and transmits the blue light LB.

  The first reflection mirror 8a is disposed in the optical path of the red light LR. The first reflection mirror 8a reflects the red light LR that has passed through the first dichroic mirror 7a toward the light modulation device 4R for red light. The second reflection mirror 8b and the third reflection mirror 8c are arranged in the optical path of the blue light LB. The second reflection mirror 8b and the third reflection mirror 8c guide the blue light LB transmitted through the second dichroic mirror 7b to the blue light modulation device 4B. The green light LG is reflected by the second dichroic mirror 7b and travels toward the green light modulation device 4G.

  The first relay lens 9a and the second relay lens 9b are disposed on the light emission side of the second dichroic mirror 7b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for the optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG. have.

  The light modulator for red light 4R modulates the red light LR according to image information to form image light corresponding to the red light LR. The green light modulation device 4G modulates the green light LG according to image information to form image light corresponding to the green light LG. The blue light light modulation device 4B modulates the blue light LB according to the image information to form image light corresponding to the blue light LB.

  For example, a transmissive liquid crystal panel is used for the light modulator for red light 4R, the light modulator for green light 4G, and the light modulator for blue light 4B. In addition, polarizing plates (not shown) are arranged on the incident side and the emission side of the liquid crystal panel, respectively. The polarizing plate transmits linearly polarized light in a specific direction.

  A field lens 10R is disposed on the incident side of the red light light modulation device 4R. A field lens 10G is disposed on the incident side of the green light modulator 4G. A field lens 10B is disposed on the incident side of the blue light modulator 4B. The field lens 10R collimates the red light LR incident on the red light light modulation device 4R. The field lens 10G collimates the green light LG incident on the green light modulator 4G. The field lens 10B collimates the blue light LB incident on the blue light modulator 4B.

  The combining optical system 5 combines the image light corresponding to each of the red light LR, the green light LG, and the blue light LB, and emits the combined image light toward the projection optical system 6. For example, a cross dichroic prism is used for the combining optical system 5.

  The projection optical system 6 includes a projection lens group including a plurality of projection lenses. The projection optical system 6 enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. As a result, an enlarged color image is displayed on the screen SCR.

Next, the light source device 2 will be described. FIG. 2 is a diagram showing a schematic configuration of the light source device 2.
As shown in FIG. 2, the light source device 2 includes an array light source 21, a collimating optical system 22, a condensing optical system 23, a phosphor wheel 10, a pickup optical system 40, an integrator optical system 31, and a polarization conversion. An element 32, a superimposing optical system 33, and a distance adjusting device 60 are provided.

  The array light source 21, the collimating optical system 22, the condensing optical system 23, the pickup optical system 40, the integrator optical system 31, the polarization conversion element 32, and the superimposing optical system 33 are sequentially arranged on the optical axis ax1. Is arranged in.

  The array light source 21 includes a plurality of semiconductor lasers (excitation light sources) 21a. The plurality of semiconductor lasers 21a are arranged in an array in a plane orthogonal to the optical axis ax1. The number of semiconductor lasers 21a is not particularly limited.

  The semiconductor laser 21a emits blue excitation light, for example. The excitation light BL is emitted from the array light source 21 toward the collimating optical system 22. The excitation light BL in the present embodiment corresponds to the excitation light in the first wavelength band in the claims.

  The excitation light BL emitted from the array light source 21 enters the collimating optical system 22. The collimating optical system 22 converts the excitation light BL emitted from the array light source 21 into a parallel light beam. The collimating optical system 22 includes a plurality of collimator lenses 22a arranged in an array, for example. The plurality of collimator lenses 22a are arranged corresponding to the plurality of semiconductor lasers (light emitting elements) 21a, respectively.

  The excitation light BL converted into a parallel light beam by passing through the collimating optical system 22 enters the condensing optical system 23. The condensing optical system 23 causes the excitation light BL to be incident on a predetermined position of the phosphor wheel 10 while being condensed.

FIG. 3 is a configuration diagram illustrating an example of the phosphor wheel 10, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a cross-sectional view.
The phosphor wheel 10 is a transmission type rotating fluorescent plate. As shown in FIGS. 3A and 3B, the phosphor wheel 10 includes a disc-shaped rotating substrate (base material) 10a that is rotationally driven by a motor 12, and a circumferential direction (on one surface of the rotating substrate 10a). A dielectric multilayer film 16 formed along the rotation direction) and a ring-shaped phosphor layer 11 formed on the dielectric multilayer film 16.

  The rotating substrate 10 a rotates around the rotation axis O at a predetermined number of rotations when the projector 1 is used. As a result, the excitation light BL is prevented from continuously entering a specific region of the phosphor layer 11, so that the lifetime of the phosphor layer 11 is extended.

  The rotating substrate 10a is made of a material that transmits the excitation light BL. As a material of the rotating substrate 10a, for example, quartz glass, quartz, sapphire, optical glass, transparent resin, or the like can be used. In the present embodiment, a disk-shaped glass substrate is used as the rotating substrate 10a.

  The phosphor layer 11 has phosphor particles that emit fluorescence, and has a function of absorbing the excitation light BL (blue light) and converting it into yellow fluorescence YL.

  The phosphor particles are particulate fluorescent materials that absorb the excitation light BL and emit fluorescence. For example, the phosphor particles include a substance that emits fluorescence when excited by blue light having a wavelength of about 450 nm, and the excitation light BL is converted into yellow fluorescence YL and emitted.

  As the phosphor particles, commonly known YAG (yttrium, aluminum, garnet) phosphors can be used. The phosphor particle forming material may be one kind, or a mixture of particles formed using two or more kinds of forming materials may be used as the phosphor particles.

  The dielectric multilayer film 16 functions as a dichroic mirror and has a characteristic of transmitting the excitation light BL and reflecting the fluorescence YL emitted from the phosphor layer 11.

  Part of the excitation light BL incident on the phosphor layer 11 is converted into fluorescence YL by being absorbed by the phosphor particles. The fluorescence YL is emitted from the phosphor layer 11 to the outside directly or after being reflected by the dielectric multilayer film 16. On the other hand, components of the excitation light BL that are not absorbed by the phosphor particles (a part of the excitation light BL) are emitted from the phosphor layer 11 to the outside.

  Returning to FIG. 2, the fluorescent light YL emitted from the phosphor layer 11 of the phosphor wheel 10 and the blue light BL1 which is a component of the excitation light BL constitute white illumination light WL. The illumination light WL is incident on the integrator optical system 31 via the pickup optical system 40. The pickup optical system 40 includes a first lens 40a and a second lens 40b.

  The integrator optical system 31 divides the illumination light WL into a plurality of small light beams. The integrator optical system 31 includes, for example, a first lens array 31a and a second lens array 31b. The first lens array 31a and the second lens array 31b are composed of a plurality of lenses arranged in an array.

  The illumination light WL (a plurality of small light beams) emitted from the integrator optical system 31 enters the polarization conversion element 32. The polarization conversion element 32 converts the illumination light WL into linearly polarized light. The polarization conversion element 32 includes, for example, a polarization separation film, a phase difference plate, and a mirror.

  The illumination light WL emitted from the polarization conversion element 32 enters the superimposing lens 33a. The superimposing lens 33a superimposes a plurality of small light beams emitted from the polarization conversion element 32 on the illumination object. Thereby, an illumination target object can be illuminated uniformly. The superimposing optical system 33 according to this embodiment includes an integrator optical system 31 including a first lens array 31a and a second lens array 31b, and a superimposing lens 33a.

  By the way, in the light source device 2, when the intensity of the excitation light BL emitted from the semiconductor laser 21a of the array light source 21 decreases with time due to some cause such as failure or deterioration with time, the white balance of the illumination light WL is shifted. End up.

  On the other hand, the light source device 2 of the present embodiment is based on a detection device (color balance detection device) 45 that measures the white balance of the illumination light WL and a measurement result obtained by the detection device 45. A distance adjusting device 60 that adjusts the distance D between the system 23 and the phosphor layer 11.

  The detection device 45 includes a light amount monitoring mirror 42 and a sensor unit 43. The light quantity monitor mirror 42 is for guiding a part of the illumination light WL to the sensor unit 43. The sensor unit 43 is for measuring the color balance (white balance) of the illumination light WL.

  The distance adjusting device 60 includes a moving mechanism 50 that moves the condensing optical system 23 relative to the phosphor wheel 10 and a control device CONT that controls the moving mechanism 50 based on the detection result of the sensor unit 43. Based on this configuration, the distance adjusting device 60 adjusts the distance between the phosphor layer 11 and the condensing optical system 23 according to the white balance of the illumination light WL.

  In the present embodiment, a light amount monitoring mirror 42 is provided on the optical path between the pickup optical system 40 and the integrator optical system 31. The light quantity monitor mirror 42 is disposed so as to form an angle of 45 ° with respect to the optical axis ax1. The light quantity monitor mirror 42 transmits a part of the incident light and reflects the rest. The light transmitted through the light quantity monitor mirror 42 enters the integrator optical system 31, and the light reflected by the light quantity monitor mirror 42 enters the sensor unit 43.

  The sensor unit 43 includes, for example, an RGB color sensor. The sensor unit 43 can separate the white light guided by the light quantity monitoring mirror 42 into red (R), green (G), and blue (B) light, and detect the light quantity of each color. That is, the sensor unit 43 can measure the amount of light (intensity) of blue light (excitation light BL) and yellow light (fluorescence YL) including red light and green light.

  The sensor unit 43 outputs a detection signal indicating the light amount (intensity) of the blue light BL1 and the light amount (intensity) of the yellow fluorescence YL to the control device CONT. The control device CONT controls the moving mechanism 50 based on the output result from the sensor unit 43 and adjusts the distance D by moving the phosphor wheel 10 as will be described later.

  The moving mechanism 50 is composed of, for example, an actuator or the like, and can move the condensing optical system 23 along the direction of the optical axis ax1. When the condensing optical system 23 moves along the direction of the optical axis ax1, the distance D between the condensing optical system 23 and the phosphor layer 11 on the phosphor wheel 10 changes. The moving mechanism 50 adjusts the distance D so that the spot diameter of the excitation light BL formed on the phosphor layer 11 by the condensing optical system 23 becomes a predetermined size as will be described later.

  When the distance D changes, the condensing optical system 23 is in either a defocused state or a focused state.

  Here, when the condensing optical system 23 is in a defocused state, the excitation light BL is out of focus on the phosphor layer 11. Therefore, the spot diameter of the excitation light BL formed on the phosphor layer 11 is relatively large.

  On the other hand, when the condensing optical system 23 is in the focus state, the excitation light BL is in focus on the phosphor layer 11. Therefore, the spot diameter of the excitation light BL formed on the phosphor layer 11 is the smallest.

  In the present embodiment, the distance D is adjusted so that the condensing optical system 23 is in the defocused state in the initial state. Therefore, in the present embodiment, in the initial state, the spot diameter of the excitation light BL formed on the phosphor layer 11 is larger than the minimum size in the focus state. Here, the initial state means a timing at which the operation of the projector 1 starts.

  In the present embodiment, since the spot diameter of the excitation light BL is larger than the minimum size in the initial state, it is possible to not only increase the spot diameter but also reduce the spot diameter by adjusting the distance D. It is. Thereby, the light quantity per unit area of the excitation light BL condensed on the phosphor layer 11 can be adjusted.

  Here, it is assumed that the amount of the excitation light BL emitted from the semiconductor laser 21a is reduced due to the change over time when the projector is used. The concept of the color balance adjustment method of the present embodiment for the white balance deviation that occurs in this case will be described based on the flowchart of FIG.

  When the output of the semiconductor laser (solid light source) 21a decreases (step S1 in FIG. 4), the amount of excitation light BL that excites the phosphor layer 11 decreases accordingly. A decrease in the light amount of the excitation light BL is equivalent to a decrease in the light density (the light amount per unit area) of the excitation light BL (step S2 in FIG. 4).

  The phosphor layer 11 generally has a characteristic that when the light density of the excitation light BL decreases, the conversion efficiency when converting the excitation light BL into fluorescence light increases. Therefore, even if the light amount of the excitation light BL decreases, the fluorescence emitted from the phosphor layer 11 when the increase amount of the fluorescence YL due to the increase in conversion efficiency exceeds the decrease amount of the fluorescence YL due to the decrease in the light amount of the excitation light BL. The amount of YL light increases (step S3 in FIG. 4). Here, the case where the light amount of the fluorescence YL increases will be described as an example, but the light amount of the fluorescence YL may decrease. However, in any case, the white balance is lost.

  Here, as the output of the semiconductor laser 21a decreases, the light amounts of the excitation light BL and the blue light BL1 both decrease. However, since the conversion efficiency of the phosphor layer 11 is increased, the ratio of the fluorescence YL to the blue light BL1 is increased. That is, the amount of fluorescence YL increases relatively (step S4 in FIG. 4). As a result, the white balance of the white illumination light WL, which is the combined light of the blue light BL1 and the yellow fluorescence YL, is lost before the change with time (step S5 in FIG. 4). Specifically, the illumination light WL, which is the combined light, changes to yellowish white light.

  In the present embodiment, the detection device 45 uses the sensor unit 43 to measure the light amount (intensity) of the blue light BL1 and the light amount (intensity) of the yellow fluorescence YL included in the light extracted by the light amount monitor mirror 42. (Step S6 in FIG. 4). The measurement result of the sensor unit 43 is transmitted to the control device CONT. This step corresponds to a “color balance measuring step” described in the claims.

  The control device CONT stores in advance, as a reference value, a ratio (intensity ratio) between blue light intensity and yellow light intensity, which is determined based on an initial intensity value at the start of use of the projector 1. The control device CONT compares the current intensity ratio detected by the sensor unit 43 with a reference value. When the difference between the current intensity ratio and the reference value exceeds the allowable range, the intensity ratio is increased by moving the condensing optical system 23 with respect to the phosphor wheel 10 along the optical axis ax1 by the moving mechanism 50. The distance D between the phosphor layer 11 and the condensing optical system 23 is adjusted so as to approach the reference value (step S7 in FIG. 4). This step corresponds to an “adjustment step” described in the claims. Specifically, the distance adjusting device 60 moves the condensing optical system 23 so as to approach the focus state. Thereby, the spot diameter of the excitation light BL on the phosphor layer 11 is reduced.

  When the spot diameter of the excitation light BL on the phosphor layer 11 is reduced, the light density of the excitation light BL irradiated to the phosphor layer 11 is increased. When the light density of the excitation light BL increases, the conversion efficiency when converting the excitation light BL in the phosphor layer 11 into the fluorescence YL decreases.

  Then, the ratio of the blue light BL1 to the fluorescence YL in the light emitted from the phosphor layer 11 increases. Thereby, compared with the case where the white balance of white light collapse | crumbles, the illumination light WL which is synthetic | combination light turns into light nearer white, and can improve white balance (step S8 of FIG. 4).

  On the other hand, in order to reduce the amount of blue light BL1 and increase the amount of fluorescent YL that is yellow light, it is only necessary to improve the conversion efficiency when converting the excitation light BL in the phosphor layer 11 into fluorescent light. That is, the distance adjusting device 60 sets the condensing optical system 23 so as to increase the spot diameter of the excitation light BL on the phosphor layer 11 in order to reduce the light density of the excitation light BL irradiated to the phosphor layer 11. Move.

  Then, since the excitation light BL is efficiently converted into the fluorescence YL, the ratio of the blue light BL1 to the fluorescence YL in the light emitted from the phosphor layer 11 decreases. Thereby, compared with the case where the white balance of white light collapse | crumbles, the illumination light WL which is synthetic | combination light turns into light nearer white, and can improve white balance (step S8 of FIG. 4).

As described above, according to the light source device 2 of the present embodiment, the spot diameter of the excitation light BL irradiated to the phosphor layer 11 is based on the blue light intensity and the yellow light intensity detected by the sensor unit 43. By controlling the size, it is possible to adjust the light amount balance of the fluorescence YL and the blue light BL1.
Accordingly, it is possible to correct the white balance deviation caused in the illumination light WL due to a cause such as failure or deterioration with time, and to adjust the white balance well.

  In addition, since the projector 1 of the present embodiment includes the light source device 2, it is possible to display an image with excellent white balance.

The white balance adjustment is desirably performed immediately after the main power supply of the projector 1 is turned on, for example.
The reason for this is that if the white balance is adjusted immediately after the main power supply of the projector 1 is turned on, it is difficult for the user to recognize a change in the color of the image. However, if the white balance is adjusted only immediately after the main power supply of the projector 1 is turned on, it cannot cope with a case where the white balance is shifted while the projector 1 is being used. Therefore, even when the projector 1 is in use, the white balance may be adjusted at predetermined time intervals.

(Modification)
Then, the modification of this invention is demonstrated.
In the above embodiment, the case where the white balance of the illumination light WL is shifted due to a decrease in the intensity of the excitation light BL emitted from the semiconductor laser 21a of the array light source 21 due to a failure, deterioration with time, or the like in the light source device 2. As an example, in this modification, a case where white balance deviation due to another cause is adjusted will be described.

  The difference between the present modification and the first embodiment is white balance adjustment, and the basic apparatus configuration is common. Therefore, in the following, the same reference numerals are given to configurations common to the above-described embodiment, and detailed description thereof is omitted or simplified.

  As a cause of the white balance shift, in addition to the above-mentioned failure and deterioration with time, the phosphor layer 11 may have a variation in thickness during manufacture. It is difficult to completely eliminate such variation in the thickness of the phosphor layer 11.

  If the thickness of the phosphor layer 11 varies, the amount of fluorescence YL emitted from the phosphor layer 11 varies. Then, the white balance of the illumination light WL obtained by combining the yellow fluorescent light YL and the blue light BL1 varies.

  The present invention is also applicable when adjusting the deviation of white balance due to the variation in the thickness of the phosphor layer 11.

  When the thickness of the phosphor layer 11 is larger than the reference value, the ratio of the light amount of the fluorescence YL to the light amount of the blue light BL1 is larger than the reference value. That is, the white balance of the illumination light WL that is the combined light of the blue light BL1 and the yellow fluorescent light YL deviates from the reference value. Specifically, the illumination light WL is yellowish white light.

  The detection device 45 measures the light amount (intensity) of the blue light BL1 and the light amount (intensity) of the yellow fluorescent light YL in the illumination light WL, and transmits them to the control device CONT. Based on the result transmitted from the sensor unit 43, the control device CONT adjusts the distance D between the phosphor layer 11 and the condensing optical system 23 so that the white balance approaches the reference value (step in FIG. 4). (See S7).

  The distance adjusting device 60 moves the condensing optical system 23 so as to approach the focus state, and reduces the spot diameter of the excitation light BL on the phosphor layer 11. Thereby, as described in the above embodiment, the white balance can be improved (see step S8 in FIG. 4).

  On the other hand, when the thickness of the phosphor layer 11 is smaller than the reference value, the ratio of the light amount of the fluorescence YL to the light amount of the blue light BL1 is smaller than the reference value. That is, the white balance of the illumination light WL deviates from the reference value. Specifically, the illumination light WL is white light with a blue tint.

  In this case, the distance adjusting device 60 moves the condensing optical system 23 so that the spot diameter of the excitation light BL on the phosphor layer 11 is increased. Thereby, as described in the above embodiment, the white balance can be improved (see step S8 in FIG. 4).

As described above, according to this modification, the spot diameter of the excitation light BL irradiated to the phosphor layer 11 is controlled based on the blue light intensity and the yellow light intensity detected by the sensor unit 43. By doing so, the light quantity balance of the fluorescence YL and the blue light BL1 can be adjusted.
Accordingly, it is possible to correct the white balance deviation caused in the illumination light WL due to the variation in the thickness of the phosphor layer 11 and to adjust the white balance well. Moreover, since the demand for the tolerance of the thickness of the phosphor layer 11 can be relaxed, the production cost can be suppressed by improving the yield.

  In addition, this invention is not necessarily limited to the said form, A various change can be added in the range which does not deviate from the meaning of this invention.

In the above-described embodiment, the case where the light quantity monitoring mirror 42 is installed between the pickup optical system 40 and the integrator optical system 31 is described as an example, but the installation location of the mirror is not limited to this.
For example, the light quantity monitoring mirror 42 may be disposed on the optical path between the integrator optical system 31 and the polarization conversion element 32, or may be disposed on the optical path between the polarization conversion element 32 and the superimposing lens 33a. It may be.

Moreover, in the said embodiment, although the thing of the transmission system which inject | emits illumination light WL to the surface on the opposite side to the surface into which excitation light BL injected as an example was mentioned as the fluorescent substance wheel 10, this invention is not limited to this. For example, as the phosphor wheel, a reflection type that emits the illumination light WL to the same surface as the surface on which the excitation light BL is incident may be employed.
Such a reflective phosphor wheel has a rotating substrate made of metal having excellent heat dissipation and a reflecting film formed between the rotating substrate and the phosphor layer. When the present invention is applied to a light source device using such a reflective phosphor wheel, the distance between the pickup optical system disposed opposite to the phosphor layer and the phosphor layer may be adjusted. The pickup optical system functions as a condensing optical system that condenses excitation light on the phosphor layer.

Moreover, although the said embodiment illustrated what light-emitted the incident light with respect to the fluorescent substance layer formed on the fluorescent substance wheel 10 as a light source device, and produced illumination light, this invention is not limited to this.
For example, the present invention can also be applied to a light source device that generates illumination light by irradiating a phosphor layer fixedly arranged on a substrate with excitation light instead of a phosphor wheel.

  In the above-described embodiment, the projector 1 including the three light modulation devices 4R, 4G, and 4B is exemplified. However, the projector 1 can be applied to a projector that displays a color image with one liquid crystal light modulation device. A digital mirror device may be used as the light modulation device.

  Moreover, although the example which mounted the light source device by this invention in the projector was shown in the said embodiment, it is not restricted to this. The light source device according to the present invention can be applied to lighting fixtures, automobile headlights, and the like.

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Light source device, 4R ... Light modulator for red light, 4G ... Light modulator for green light, 4B ... Light modulator for blue light, 11 ... Phosphor layer, 21a ... Semiconductor laser (light emitting element) 22 ... Collimating optical system, 23 ... Condensing optical system, 45 ... Detection device, 60 ... Distance adjustment device, YL ... Fluorescence, BL1 ... Blue light (part of light).

Claims (5)

A light emitting element;
A collimating optical system on which excitation light emitted from the light emitting element is incident;
A condensing optical system on which the excitation light emitted from the collimating optical system is incident;
A part of the excitation light incident from the condensing optical system, and a phosphor layer that emits fluorescence as illumination light;
A color balance detection device for measuring the color balance of the illumination light;
Based on the measurement result obtained by the color balance detection device, the spot diameter of the excitation light formed on the phosphor layer by adjusting the distance between the condensing optical system and the phosphor layer A distance adjusting device that changes the size of
The distance adjusting device includes a moving mechanism that moves the condensing optical system with respect to the phosphor layer, and a control device that controls the moving mechanism based on a detection result of the color balance detecting device,
The control device compares a reference value stored in advance with a detection value of the color balance detection device, and if the difference between the reference value and the detection value exceeds a predetermined threshold, the detection value is set as the reference value. Controlling the moving mechanism to approach ,
The distance adjusting device adjusts the distance between the condensing optical system and the phosphor layer so that the spot diameter of the excitation light is reduced when the intensity of the fluorescence is larger than the intensity of the excitation light, A light source device that adjusts the distance between the condensing optical system and the phosphor layer so that the spot diameter of the excitation light is increased when the intensity of fluorescence is smaller than the intensity of the excitation light . The light source device according to claim 1, wherein in the initial state, the distance adjustment device adjusts the distance so that the condensing optical system is in a defocused state. The light source device according to claim 1 or 2,
A light modulation device that forms image light by modulating illumination light from the light source device according to image information;
A projection optical system that projects the image light. A light emitting element;
A collimating optical system on which excitation light emitted from the light emitting element is incident;
A condensing optical system on which the excitation light emitted from the collimating optical system is incident;
A method for adjusting the color balance of a light source device comprising: a part of the excitation light incident from the condensing optical system; and a phosphor layer that emits fluorescence as illumination light,
A color balance measuring step for measuring the color balance of the illumination light;
Based on the measurement result obtained by the color balance measurement step, the spot diameter of the excitation light formed on the phosphor layer by adjusting the distance between the condensing optical system and the phosphor layer An adjustment process for changing the size of
In the adjustment step, the reference value stored in advance is compared with the measurement value obtained in the color balance measurement step, and when the difference between the reference value and the measurement value exceeds a predetermined threshold, the measurement value is converted to the reference value. Moving the condensing optical system relative to the phosphor layer so as to approach the value ,
When the intensity of the fluorescence is greater than the intensity of the excitation light, the distance between the condensing optical system and the phosphor layer is adjusted so that the spot diameter of the excitation light is small, and the intensity of the fluorescence is A color balance adjustment method for adjusting a distance between the condensing optical system and the phosphor layer so that a spot diameter of the excitation light is increased when the intensity is smaller than light intensity . The color balance adjustment method according to claim 4, wherein the distance is adjusted so that the condensing optical system is in a defocus state in an initial state before the start of color balance adjustment.

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