JP2012043700A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device capable of prolonging its life through cancellation of temperature distribution generated by a plurality of solid light sources, and a projector equipped with the light source device.SOLUTION: The light source device is provided with: a solid light source array 11 equipped with a plurality of solid light sources 11a classified into a plurality of blocks B1-B4 in accordance with the temperature distribution generated when driven with constant current; and a driving device D which drives a plurality of the solid light sources 11a arranged in the solid light source array 11 by changing driving current for each block B1-B4, so that the temperature distribution becomes even.

Description

  The present invention relates to a light source device and a projector.

  Solid light sources such as LDs (Laser Diodes) and LEDs (Light Emitting Diodes) have lower power consumption, longer life, less heat generation, and smaller size than halogen lamps and high-pressure mercury lamps. It is possible to make it easier to control the lighting and extinguishing. For this reason, in recent years, light source devices including a solid light source have begun to be used rapidly in various fields. For example, in a projector that displays an image on a screen, a light source device including a solid-state light source has been actively used mainly for the purpose of suppressing power consumption and heat generation and reducing the size and weight.

  When a larger amount of light is required than the amount of light emitted from one solid-state light source, a light source device including a plurality of solid-state light sources arranged in a linear or planar shape is used. For example, the projector described above requires a light amount that allows the image displayed on the screen illuminated by a lighting device such as a fluorescent lamp to be recognized to some extent, and thus a light source in which a plurality of solid light sources are arranged. Equipment is almost essential.

  The following Patent Document 1 includes a plurality of first laser light emitting units and a plurality of second laser light emitting units disposed between the first laser light emitting units, and the first laser light emitting unit and the second laser light emitting unit. A light source device that sequentially switches driving with a laser light emitting unit is disclosed. Patent Document 2 below discloses a semiconductor laser light source device including a plurality of laser units each including a semiconductor laser and a Peltier element that controls the temperature of the semiconductor laser.

JP 2009-152540 A JP 2005-191223 A

  As described above, solid light sources such as LDs and LEDs generate less heat than conventional lamps, but the amount of heat generated is not zero, and heat is generated according to the amount of drive current. In a light source device having a plurality of solid light sources, even if all the solid light sources are driven with the same current, the temperature distribution is caused by the heat generated from each of the solid light sources depending on the arrangement of the solid light sources and the cooling method of the light source devices. Arise. For example, in a light source device including a plurality of solid state light sources arranged in a planar shape, the temperature of the central portion tends to increase and the temperature of the peripheral portion tends to decrease.

  Solid light sources such as LDs and LEDs are a type of semiconductor element, and therefore tend to deteriorate as the temperature increases. For this reason, in the above-described example, the deterioration of the solid light source disposed in the central portion where the temperature tends to be high among the plurality of solid light sources arranged in a planar shape becomes the fastest. In a light source device including a plurality of solid state light sources, when the lifetime of the solid light source that is most rapidly deteriorated is considered as the lifetime of the light source device, there is a problem that the lifetime of the light source device itself is shortened due to the temperature distribution described above.

  Here, in Patent Document 1 described above, the plurality of laser light emitting units are divided into the first laser light emitting unit and the second laser light emitting unit, and the driving is switched for each division. If the driving method is devised, the temperature distribution can be changed. However, in Cited Document 1, the division of the plurality of laser light emitting units is determined in consideration of ease of control, and no consideration is given to the temperature distribution. It is thought that the temperature distribution cannot be changed. Moreover, although patent document 2 mentioned above discloses the point which cools a semiconductor laser using a Peltier device, it does not disclose at all about the point which eliminates the temperature distribution which arises with the solid light source arranged in multiple numbers.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a light source device capable of eliminating the temperature distribution caused by a plurality of solid light sources and extending the life thereof, and a projector including the light source device. .

The light source device according to the present invention includes a plurality of solid light sources divided into a plurality of blocks according to a temperature distribution generated when driven with a constant current, and the plurality of solids so that the temperature distribution is uniform. The light source includes a drive device that drives the light source by changing a drive current for each of the blocks.
According to the present invention, a plurality of solid state light sources are divided into a plurality of blocks according to the temperature distribution generated when driven with a constant current, and the drive current is changed for each block so that the temperature distribution is uniform. Since the plurality of solid state light sources are driven, the temperature distribution caused by the plurality of solid state light sources can be eliminated and the life can be extended.
Further, in the light source device of the present invention, the driving device can obtain the same light amount as a reference light amount that is a light amount of light emitted when the plurality of solid state light sources are driven with the constant current. It is characterized by changing the drive current for each block.
According to the present invention, the drive current for each block can be changed so as to obtain the same light amount as the reference light amount, so that the necessary light amount can be obtained while the temperature distribution is made uniform.
Specifically, in the light source device of the present invention, the driving device includes at least one block located in a portion where the temperature of the temperature distribution generated when the plurality of solid state light sources are driven with the constant current is highest. The drive current is reduced from the constant current.
Here, in the light source device of the present invention, the drive device has at least one of the blocks other than the block in which the drive current is reduced so that the temperature distribution is uniform and the reference light amount is obtained. One driving current is increased more than the constant current.
By controlling the drive current as described above, a portion where the temperature is locally high or low can be eliminated and the temperature distribution can be made uniform, so that the life can be extended.
The light source device of the present invention is characterized in that the driving device includes a plurality of driving circuits that are provided corresponding to the blocks and that drive the solid-state light sources included in the corresponding blocks.
According to the present invention, since the drive circuit for driving the solid state light source included in each block is provided corresponding to each block, the drive current can be easily controlled.
Further, the light source device of the present invention includes a temperature sensor provided for each block, and the driving device changes a driving current for each block with reference to a detection result of the temperature sensor. Yes.
According to the present invention, since the drive current for each block can be changed based on the temperature detected by the temperature sensor, the temperature distribution can be made uniform with higher accuracy.
Further, the light source device of the present invention is characterized in that each of the plurality of blocks is divided so as to include the same number.
According to the present invention, since the same number of solid-state light sources are included in each block, the configuration of each drive circuit can be made the same, and the drive circuit can be easily designed.
Moreover, the light source device of the present invention is characterized in that the plurality of solid state light sources are arranged in a linear shape or a planar shape.
According to the present invention, not only when a plurality of solid light sources are arranged in a planar shape, but also may be arranged in a linear shape, it can be applied to various light source devices including a plurality of solid light sources.
The projector according to the present invention includes a light source device, a light modulation device that modulates light from the light source device, and a projection optical system that projects light modulated by the light modulation device onto a screen. The light source device according to any one of the above is provided.

It is a block diagram which shows the principal part structure of the light source device by 1st Embodiment of this invention. It is a figure which shows the 1st modification of the light source device by 1st Embodiment of this invention. It is a figure which shows the 2nd modification of the light source device by 1st Embodiment of this invention. It is a figure which shows the 3rd modification of the light source device by 1st Embodiment of this invention. It is a figure which shows the 4th modification of the light source device by 1st Embodiment of this invention. It is a figure which shows the structure of the projector by 1st Embodiment of this invention. It is a figure which shows the structure of the projector by 2nd Embodiment of this invention.

  Hereinafter, a light source device and a projector according to embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below show some aspects of the present invention and do not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention.

[First Embodiment]
FIG. 1 is a block diagram showing the main configuration of the light source device according to the first embodiment of the present invention. As shown in FIG. 1, the light source device 1 of this embodiment includes a solid light source array 11 and a driving device D, and emits blue light, for example, when the solid light source array 11 is driven by the driving device D.

  The solid light source array 11 includes a plurality of solid light sources 11a arranged in a planar shape (matrix shape) on a substantially rectangular substrate SB, and emits blue light when driven by the driving device D. In FIG. 1, in order to avoid complication, the solid light source array 11 including a total of 16 solid light sources 11 a in which four solid light sources 11 a are arranged in the vertical direction and the horizontal direction of the paper is illustrated. . The number of the solid light sources 11a can be appropriately increased or decreased according to the required light amount.

  The solid light source 11a is a semiconductor laser that emits blue light (peak of emission intensity: about 460 nm). The solid-state light source 11a is divided into a plurality of blocks B1 to B4 according to a temperature distribution generated when each of the solid-state light sources 11a is driven with a constant current by the driving device D. Here, the above “constant current” is a current having a common magnitude for all of the solid light sources 11 a included in the solid light source array 11, and blue light having a preset light amount (reference light amount) is emitted from the light source device 1. This is the current required to inject from.

  Specifically, the solid light source 11a includes a block B1 including four solid light sources 11a arranged in the central portion of the substrate SB, and the remaining twelve solid light sources 11a arranged in the peripheral portion of the substrate SB. It is divided into blocks B2 to B4 each including four blocks. As shown in FIG. 1, the block B2 includes four solid light sources arranged along one side (the upper side in the drawing) of the twelve solid light sources 11a arranged in the peripheral portion of the substrate SB. 11a is included. The block B3 includes four solid light sources 11a arranged on the right side of the paper among the remaining eight solid light sources 11a, and the block B4 includes the remaining four solid light sources 11a (arranged on the left side of the paper). Four solid-state light sources 11a).

  The four solid light sources 11a arranged in the center of the substrate SB are surrounded by twelve solid light sources 11a. In contrast, the twelve solid light sources 11a arranged in the peripheral portion of the substrate SB are not surrounded by the solid light sources 11a. For this reason, the solid light source array 11 is disposed horizontally (arrangement where the substrate SB is parallel or substantially parallel to the horizontal plane), and all of the solid light sources 11a included in the solid light source array 11 are driven with a constant current. The heat generated from each of the solid light sources 11a is trapped in the central portion of the substrate SB, the temperature is highest at the central portion of the substrate SB, and the temperature gradually decreases as it goes to the peripheral portion of the substrate SB. Distribution occurs. According to such temperature distribution, the solid-state light source 11a is roughly divided into a block B1 in the central portion of the substrate SB and blocks B2 to B4 in the peripheral portion.

  Here, if only the above temperature distribution is taken into consideration, the block B1 in the center of the substrate SB and the block in the peripheral portion of the substrate SB in which the blocks B2 to B4 are combined into one may be divided. However, in the present embodiment, the twelve solid-state light sources 11a arranged in the peripheral part of the substrate SB are divided into three blocks B2 to B4. This is to make the number of solid light sources 11a included in each of the blocks B1 to B4 the same. If the number of the solid light sources 11a included in each of the blocks B1 to B4 is the same, the drive circuits D1 to D4 provided corresponding to each of the blocks B1 to B4 can have the same configuration, and thus the drive circuit D1. Design of ~ D4 becomes easy.

  The solid light source 11a is divided into blocks B1 to B4. The solid light source 11a is generated from the solid light source 11a by driving the solid light source 11a for each of the blocks B1 to B4 and changing the drive current for each of the blocks B1 to B4. This is because the temperature distribution due to heat generated is made uniform to extend the life of the light source device 1. That is, the solid light source 11a is a kind of semiconductor element and tends to be deteriorated when the temperature becomes high. Therefore, the degree of deterioration of all the solid light sources 11a provided in the solid light source array 11 with uniform temperature distribution is set. The life of the light source device 1 is extended by making it substantially equal.

  The driving device D includes driving circuits D <b> 1 to D <b> 4 and drives a solid light source 11 a provided in the solid light source array 11. The drive circuits D1 to D4 are provided corresponding to the blocks B1 to B4, respectively, and drive the solid light sources 11a included in the corresponding blocks under the control of the drive device D. Specifically, the driving device D controls the driving currents of the driving circuits D1 to D4 so that the temperature distribution generated when all of the solid light sources 11a included in the solid light source array 11 are driven with a constant current becomes uniform. To do. At this time, the drive device D controls the drive currents of the drive circuits D1 to D4 so as to obtain the same light amount as the reference light amount described above while achieving uniform temperature distribution.

  For example, the drive device D controls the drive circuit D1 to reduce the drive current for the block B1 in the central portion of the substrate SB where the temperature is higher than the constant current, and to control the drive circuits D2 to D4. Then, the drive current for the blocks B2 to B4 in the peripheral portion of the substrate SB is increased from the above constant current. Decreasing the drive current for the block B1 reduces the amount of heat generation and the amount of light at the center of the substrate SB, and increasing the drive current for the blocks B2 to B4 increases the amount of heat generation and the amount of light at the peripheral portion of the substrate SB. Thereby, the temperature distribution is made uniform and the same light amount as the reference light amount is obtained.

  Note that the drive current required to make the temperature distribution uniform and obtain the same light amount as the reference light amount is obtained in advance by experiments or simulations. The drive circuits D1 to D4 change the drive current for each of the blocks B1 to B4 based on the results of these experiments and the like under the control of the drive device D. Here, the characteristics of the solid light source 11a provided in the solid light source array 11 may change due to aging or the like. For this reason, a temperature sensor may be provided in the solid light source array 11 and the drive current may be controlled based on the detection result of the temperature sensor.

  FIG. 2 is a diagram showing a first modification of the light source device according to the first embodiment of the present invention. In FIG. 2, in order to simplify the illustration, connection lines for connecting the solid light sources 11a in the blocks B1 to B4 are omitted. In the modification shown in FIG. 2, temperature sensors T1 to T4 are provided in the blocks B1 to B4, respectively. The detection results of these temperature sensors T1 to T4 are output to the drive circuits D1 to D4, respectively, and the drive circuits D1 to D4 block based on the detection results of the temperature sensors T1 to T4 under the control of the drive device D. The drive current for each of B1 to B4 is changed. In addition to the above temperature sensors T1 and T4, a light amount sensor that detects the amount of blue light emitted from the light source device 1 is provided, and the amount of blue light becomes equal to the reference light amount based on the detection result of the light amount sensor. Thus, the drive current for each of the blocks B1 to B4 may be controlled.

  The light source device 1 described with reference to FIGS. 1 and 2 is not cooled by the cooling device, or the solid light sources 11a arranged in a planar shape are uniformly cooled by the cooling device. The temperature was the highest at the center of the substrate SB on which 11a was arranged, and the temperature distribution gradually decreased as it went to the periphery of the substrate SB. The temperature distribution generated by the heat generation of the solid light source 11a included in the solid light source array 11 varies depending on how the solid light source array 11 is cooled, how the solid light source array 11 is arranged, or the number of solid light sources 11a. For this reason, the division of the solid light sources 11 a provided in the solid light source array 11 and the control of the drive current may be performed according to the temperature distribution that appears in the actual use state of the light source device 1.

  FIG. 3 is a diagram showing a second modification of the light source device according to the first embodiment of the present invention. As shown in FIG. 3, in this modification, the solid light source array 11 is air-cooled by the cold air W. Also in this modification, the some solid light source 11a provided in the solid light source array 11 is divided into the blocks B1-B4 similar to the solid light source array 11 shown in FIG. 1, FIG. If the solid light source array 11 is cooled by the cold air W (cool air W directed from the block B3, B4 side to the block B2 side) from the right side to the left side of the solid light source array 11, the array is arranged on the right side of the paper surface. The heat generated from the solid light source 11a is carried to the left side by the cold air W. Then, when all of the solid light sources 11a included in the solid light source array 11 are driven with a constant current, a temperature distribution is generated in which the temperature at the left end of the substrate SB is highest and then the temperature at the center of the substrate SB is high. .

  When such a temperature distribution occurs, the drive current for the block B2 that is located at the leeward side of the cold wind W and has the highest temperature is reduced most, and the block B1 that is located at the center of the substrate SB and has the next highest temperature. The drive current for is then reduced. And the drive current with respect to the blocks B3 and B4 which are located on the wind of the cold wind W and are efficiently cooled by the cold wind W is increased. Decreasing the drive current for the blocks B2 and B1 reduces the amount of heat and light at the left end and the center of the substrate SB, and increasing the drive current for the blocks B3 and B4 increases the amount of heat and light at the right end of the substrate SB. Will increase. Thereby, the temperature distribution is made uniform and the same light amount as the reference light amount is obtained. Note that the above control is also performed using a drive current obtained in advance by experiments or simulations, or using detection results of temperature sensors similar to the temperature sensors T1 to T4 shown in FIG.

  FIG. 4 is a diagram showing a third modification of the light source device according to the first embodiment of the present invention. In this modification, the solid light source array 11 is arranged vertically. Here, the vertical arrangement is an arrangement in which the substrate SB of the solid light source array 11 is perpendicular or substantially perpendicular to the horizontal plane. When the solid light source array 11 is vertically arranged, the air heated by the heat generated from each of the solid light sources 11a moves upward. For this reason, a temperature distribution is generated in which the temperature gradually increases from the bottom to the top of the substrate SB.

  Therefore, when the solid-state light source array 11 is arranged vertically, the solid-state light source 11a is divided so that the same height position is included in the same block as shown in FIG. Specifically, the solid light source 11a includes a block B11 including four solid light sources 11a arranged at the lower end of the substrate SB and a block B12 including four solid light sources 11a arranged one above the block B11. The block B13 includes four solid light sources 11a arranged one above the block B13, and the block B14 includes four solid light sources 11a arranged at the upper end of the substrate SB.

  When the solid-state light source 11a is divided into blocks B11 to B14 shown in FIG. 4, the drive current for the block B14 located at the uppermost position is the smallest, the drive current gradually increases toward the lower side, and the lowest at the bottom. The drive current is controlled so as to maximize the drive current for the block B11 located. By such control, the heat generation amount and the light amount at the upper end portion of the substrate SB are decreased, the heat generation amount and the light amount at the lower end portion of the substrate SB are increased, the temperature distribution is made uniform, and the same light amount as the reference light amount is obtained. Note that the above control is also performed using a drive current obtained in advance by experiments or simulations, or using detection results of temperature sensors similar to the temperature sensors T1 to T4 shown in FIG.

  FIG. 5 is a diagram showing a fourth modification of the light source device according to the first embodiment of the present invention. In this modification, as shown in FIG. 5, the number of solid light sources 11a provided in the solid light source array 11 is different from that shown in FIGS. The solid-state light source array 11 shown in FIG. 5 includes a total of 36 solid-state light sources 11a in which six solid-state light sources 11a are arranged in the vertical direction and the horizontal direction of the drawing. Now, the solid light source array 11 is disposed horizontally (arrangement in which the substrate SB is parallel or substantially parallel to the horizontal plane) and is not cooled by the cooling device, or is arranged in a planar shape. It is assumed that 11a is uniformly cooled by the cooling device.

  When all of the solid light sources 11a included in the solid light source array 11 are driven with a constant current, the temperature is highest at the central portion of the substrate SB and the peripheral portion of the substrate SB is the same as that shown in FIGS. A temperature distribution is generated in which the temperature gradually decreases as the temperature increases. For this reason, the solid light source 11a shown in FIG. 5 is divided into six blocks B21 to B26 arranged in a substantially spiral shape. Specifically, the solid light source 11a includes a block B21 including six solid light sources 11a arranged at a substantially central portion of the substrate SB, and each of the solid light sources 11a includes six solid light sources 11a and spirals around the block B21. The blocks are divided into arranged blocks B22 to B26. As described above, by arranging the blocks B21 to B26 in a spiral shape, wiring can be easily routed to the solid light sources 11a included in each of the blocks B21 to B26.

  When the solid-state light source 11a is divided into blocks B21 to B26 shown in FIG. 5, the drive current for the blocks near the center of the substrate SB is reduced, and the drive current for the blocks located in the periphery is increased. Control drive current. For example, the drive current for the block B21 arranged at the center of the substrate SB is minimized, and then the drive current is gradually increased in the order of the blocks B22 and B23. Then, the drive current for the remaining blocks B24 to B26 is made larger than the drive current for the block B23. With this control, the heat generation amount and the light amount in the central portion of the substrate SB are reduced, and the heat generation amount and the light amount in the peripheral portion of the substrate SB are increased, and the temperature distribution is made uniform to obtain the same light amount as the reference light amount. Note that the above control is also performed using a drive current obtained in advance by experiments or simulations, or using detection results of temperature sensors similar to the temperature sensors T1 to T4 shown in FIG.

  Next, the projector according to the first embodiment of the invention will be described. FIG. 6 is a diagram showing the configuration of the projector according to the first embodiment of the invention. As shown in FIG. 6, the projector PJ1 includes an illumination device 10, a color separation light guide optical system 20, liquid crystal light modulation devices 30R, 30G, and 30B (light modulation devices), a cross dichroic prism 40, and a projection optical system 50. In addition, an image is displayed on the screen SCR by projecting image light according to an image signal input from the outside toward the screen SCR.

  The illumination device 10 includes the light source device 1 described above, a collimator lens array 12, a condensing optical system 13, a fluorescence generation unit 14, a collimator optical system 15, a first lens array 16, a second lens array 17, and polarization conversion. An element 18 and a superimposing lens 19 are provided, and white light including red light, green light, and blue light is emitted. The collimator lens array 12 includes a plurality of collimator lenses corresponding to each of the plurality of solid light sources 11a provided in the solid light source array 11, and substantially parallelizes the blue light emitted from each of the solid light sources 11a. To do.

  Specifically, the collimator lens array 12 is formed by arranging collimator lenses, which are 16 plano-convex lenses, in a matrix of 4 rows and 4 columns. The collimator lens array 12 is arranged with the convex surface of the collimator lens facing the solid light source array 11 and each collimator lens corresponding to each solid light source 11a. The condensing optical system 13 includes a first lens 13 a and a second lens 13 b, and condenses the blue light substantially parallelized by the collimator lens array 12 at a position near the fluorescence generator 14.

  The fluorescence generation unit 14 is disposed in the vicinity of the light collection position of the light collection optical system 13 and generates fluorescence including red light and green light from a part of the blue light collected by the light collection optical system 13. And a transparent member (not shown) for carrying the fluorescent layer. Specifically, the fluorescence generation unit 14 is disposed at a position where the blue light condensed by the condensing optical system 13 enters the phosphor layer in a defocused state. The fluorescence generation unit 14 includes blue light that passes through the phosphor layer without involving the generation of fluorescence together with the fluorescence, and emits light that becomes white light as a whole.

The above fluorescent layer is, for example, a YAG-based phosphor _{(Y, Gd) 3 (Al} , Ga) 5 O 12: a layer containing Ce. The fluorescent layer converts a part of the blue light collected by the condensing optical system 13 into fluorescence including red light (emission intensity peak: about 610 nm) and green light (emission intensity peak: about 550 nm). Convert and inject. Of the blue light, part of the blue light that passes through the fluorescent layer without being involved in the generation of fluorescence is emitted together with the fluorescence. The collimator optical system 15 includes a first lens 15a and a second lens 15b, and makes the light from the fluorescence generation unit 14 substantially parallel.

  The first lens array 16 has a plurality of small lenses 16a, and divides the light from the light source device 1 into a plurality of partial light beams. Specifically, the plurality of small lenses 16a included in the first lens array 16 are arranged in a matrix over a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis AX. The outer shape of the plurality of small lenses 16a included in the first lens array 16 is substantially similar to the outer shape of the image forming area of the liquid crystal light modulation devices 30R, 30G, and 30B.

  The second lens array 17 has a plurality of small lenses 17 a corresponding to the plurality of small lenses 16 a provided in the first lens array 16. That is, the plurality of small lenses 17a included in the second lens array 17 extends over a plurality of rows and columns within a plane orthogonal to the illumination optical axis AX, similarly to the plurality of small lenses 16a included in the first lens array 16. Arranged in a matrix. The second lens array 17 forms an image of each small lens 16a included in the first lens array 16 together with the superimposing lens 19 in the vicinity of the image forming regions of the liquid crystal light modulation devices 30R, 30G, and 30B.

  The polarization conversion element 18 includes a polarization separation layer, a reflection layer, and a retardation plate (all not shown), and the polarization direction of each partial light beam divided by the first lens array 16 is aligned with the polarization direction. It is emitted as almost one type of linearly polarized light. Here, the polarization separation layer transmits one linearly polarized light component included in the light from the light source device 1 as it is, and reflects the other linearly polarized light component in a direction perpendicular to the illumination optical axis AX. The reflective layer reflects the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis AX. Furthermore, the phase difference plate converts the other linearly polarized light component reflected by the reflective layer into one linearly polarized light component.

  The superimposing lens 19 is arranged so that the optical axis thereof coincides with the optical axis of the illumination device 10, and condenses each partial light beam from the polarization conversion element 18, and images of the liquid crystal light modulation devices 30R, 30G, and 30B. Superimpose near the formation area. The first lens array 16, the second lens array 17, and the superimposing lens 19 described above constitute a lens integrator optical system that makes light from the light source device 10 uniform.

  The color separation light guide optical system 20 includes dichroic mirrors 21 and 22, reflection mirrors 23 to 25, relay lenses 26 and 27, and condensing lenses 28R, 28G, and 28B, and converts the light from the illumination device 10 into red light. , Green light and blue light are separated and guided to the liquid crystal light modulation devices 30R, 30G and 30B, respectively. The dichroic mirrors 21 and 22 are mirrors in which a wavelength selective transmission film that reflects light in a predetermined wavelength region and transmits light in other wavelength regions is formed on a transparent substrate. Specifically, the dichroic mirror 21 reflects a red light component and transmits green light and blue light components, and the dichroic mirror 22 reflects a green light component and transmits blue light components.

  The reflection mirror 23 is a mirror that reflects a red light component, and the reflection mirrors 24 and 25 are mirrors that reflect a blue light component. The relay lens 26 is disposed between the dichroic mirror 22 and the reflection mirror 24, and the relay lens 27 is disposed between the reflection mirror 24 and the reflection mirror 25. These relay lenses 26 and 27 are provided in order to prevent a decrease in light use efficiency due to light divergence and the like because the length of the optical path of blue light is longer than the length of the optical paths of other color lights. The condensing lenses 28R, 28G, and 28B convert the red light component reflected by the reflection mirror 23, the green light component reflected by the dichroic mirror 22, and the blue light component reflected by the reflection mirror 25 into the liquid crystal light modulation device 30R. , 30G, and 30B, respectively.

  The red light reflected by the dichroic mirror 21 is reflected by the reflecting mirror 23 and enters the image forming area of the liquid crystal light modulation device 30R for red light through the condenser lens 28R. The green light that has passed through the dichroic mirror 21 is reflected by the dichroic mirror 22 and enters the image forming region of the liquid crystal light modulation device 30G for green light through the condenser lens 28G. The blue light that has passed through the dichroic mirrors 21 and 22 passes through the relay lens 26, the reflection mirror 24, the relay lens 27, the reflection mirror 25, and the condenser lens 28B in this order, and the image forming area of the liquid crystal light modulation device 30B for blue light Is incident on.

  The liquid crystal light modulation devices 30R, 30G, and 30B modulate incident color light according to an image signal input from the outside, and generate red image light, green image light, and blue image light, respectively. Although not shown in FIG. 6, incident-side polarizing plates are interposed between the condenser lenses 28R, 28G, 28B and the liquid crystal light modulators 30R, 30G, 30B, respectively. Between the modulation devices 30R, 30G, and 30B and the cross dichroic prism 40, an exit side polarizing plate is interposed.

  The liquid crystal light modulators 30R, 30G, and 30B are transmissive liquid crystal light modulators in which a liquid crystal that is an electro-optical material is hermetically sealed between a pair of transparent glass substrates. For example, a polysilicon TFT (Thin Film Transistor: A thin film transistor) as a switching element. By modulating the polarization direction of the color light (linearly polarized light) through each of the incident side polarizing plates (not shown) described above by the switching operation of the switching elements provided in each of the liquid crystal light modulation devices 30R, 30G, and 30B. Then, red image light, green image light, and blue image light corresponding to the image signal are respectively generated.

  The cross dichroic prism 40 synthesizes the image light emitted from each of the above-described exit side polarizing plates (not shown) to form a color image. Specifically, the cross dichroic prism 40 is a substantially cubic optical member formed by bonding four right-angle prisms, and a dielectric multilayer film is formed at a substantially X-shaped interface where the right-angle prisms are bonded together. Has been. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized. The projection optical system 50 enlarges and projects the color image synthesized by the cross dichroic prism 40 toward the screen SCR.

  The projector PJ1 described above includes a plurality of solid light sources 11a divided into a plurality of blocks according to a temperature distribution generated when each of them is driven with a constant current, and a plurality of solid light sources 11a so that the temperature distribution is uniform. Are provided with a light source device 1 that has a drive device D that changes the drive current for each block and can extend the life. For this reason, the projector PJ1 of the present embodiment can have a longer product life than conventional projectors. In addition, since the light source device 1 that can make the temperature distribution uniform is provided, it is possible to increase the degree of freedom in designing the device and structure for cooling the light source device 1.

[Second Embodiment]
Next, a projector according to a second embodiment of the invention will be described. FIG. 7 is a diagram showing a configuration of a projector according to the second embodiment of the invention. As shown in FIG. 7, the projector PJ2 includes illumination devices 60R, 60G, and 60B, liquid crystal light modulation devices 71R, 71G, and 71B (light modulation devices), a color synthesis system 72, and a projection optical system 73. An image is displayed on the screen SCR by projecting image light according to the input image signal toward the screen SCR.

  The illumination devices 60R, 60G, and 60B include the light source device 1, the diffractive optical system 61, and the angle adjusting optical element 62, and red light, green light, and blue light toward the liquid crystal light modulation devices 71R, 71G, and 71B. Each is irradiated with light. Here, the light source device 1 provided in the illumination device 60R emits red light, the light source device 1 provided in the illumination device 60G emits green light, and the light source device 1 provided in the illumination device 60B emits blue light. .

  The diffractive optical system 61 includes a plurality of diffractive optical elements 61a corresponding to the plurality of solid light sources 11a provided in the solid light source array 11, and the color light emitted from each of the solid light sources 11a at a predetermined angle. Diffraction. Specifically, when the solid light source array 11 includes a total of 16 solid light sources 11a as shown in FIG. 1, the diffractive optical system 61 includes a total of 16 diffractive optical elements 16a in 4 rows and 4 columns. Are arranged in a matrix. The collimator lens array 12 is arranged in a state where each diffractive optical element 61a is associated with each solid light source 11a.

  The angle adjusting optical element 62 is constituted by a refractive lens (field lens), and adjusts the angle of the color light diffracted by the diffractive optical system 61 to guide it to any one of the liquid crystal light modulation devices 71R, 71G, 71B. Provided. In the present embodiment, the angle adjusting optical element 62 is optimized so that the illuminated surface P is illuminated in a superimposed manner with the diffracted light diffracted by each of the plurality of diffractive optical elements 61a.

  By providing the angle adjusting optical element 62, the incident angle of the colored light to the liquid crystal light modulators 71R, 71G, 71B can be reduced, and the incident angle of the colored light to the liquid crystal light modulators 71R, 71G, 71B can be reduced. Therefore, the liquid crystal light modulation devices 71R, 71G, 71B can be efficiently illuminated. Since the liquid crystal light modulators 71R, 71G, 71B are superimposedly illuminated by the diffracted light generated by each of the plurality of diffractive optical elements 61a, the liquid crystal light modulators 71R, 71G, 71B are efficiently illuminated with high illuminance. It can be well lit. In addition, the generation of speckle patterns can be suppressed, and the liquid crystal light modulation devices 71R, 71G, 71B can be illuminated with a substantially uniform illuminance distribution.

  In addition, the plurality of solid light sources 11a provided in the solid light source array 11 provided in the light source device 1 has a plurality of blocks (for example, in FIG. Blocks B1 to B4) shown. Then, the solid-state light source 11a is driven for each block by the driving device D, and is driven by changing the driving current for each block. For this reason, the temperature distribution due to the heat generated from the solid light source 11a can be made uniform, and as a result, the life of the light source device 1 can be extended.

  The liquid crystal light modulators 71R, 71G, and 71B modulate incident color light according to an image signal input from the outside, and generate red image light, green image light, and blue image light, respectively. The liquid crystal light modulation device 71R receives red light from the illumination device 60R, the liquid crystal light modulation device 71G receives green light from the illumination device 60G, and the liquid crystal light modulation device 71B receives light from the illumination device 60B. Blue light is incident. The color synthesis system 72 synthesizes the image light generated by each of the liquid crystal light modulation devices 71R, 71G, and 71B. The projection optical system 73 enlarges and projects the modulated light synthesized by the color synthesis system 72 toward the screen SCR.

  The projector PJ2 described above includes a solid-state light source divided into a plurality of blocks according to the temperature distribution, and a drive device that drives the plurality of solid-state light sources by changing the drive current for each block so that the temperature distribution is uniform. It has a light source device 1 that can have a long life. Here, a projector having a plurality of light source devices needs to be replaced when one of the light source devices fails. However, the projector PJ2 of the present embodiment has a long lifetime of the light source device 1. Therefore, the product life can be made longer than before.

  The light source device and the projector according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, the following modifications are possible.

(1) In the above embodiment, the case where the solid light sources 11a arranged in the solid light source array 11 are semiconductor lasers has been described as an example, but the present invention is not limited to this. For example, the present invention can be applied to a solid light source array in which the solid light source is a light emitting diode.

(2) In the above embodiment, the example in which the number of solid light sources 11a included in each block is set to be the same has been described in order to facilitate the design of the drive circuits D to D4, but the present invention is limited to this. Is not to be done. When the design of the drive circuits D1 to D4 is not a problem, the number of solid light sources 11a included in each block may be different.

(3) In the above embodiment, an example in which the solid light sources are arranged in a planar shape has been described, but the present invention is not limited to this. For example, the present invention can also be applied when the solid light sources are arranged in a line. In addition, in the above-described embodiment, the example in which the solid light sources are arranged at constant intervals in the vertical direction and the horizontal direction of the substrate SB has been described, but the substrate SB may be arranged in a honeycomb shape. Here, the honeycomb shape means an arrangement in which solid light sources are located at respective intersections when regular hexagons are arranged on a plane without gaps.

(4) In the above embodiment, a transmissive projector has been described as an example of the projector, but the present invention is not limited to this. For example, the present invention can be applied to a reflection type projector. Here, “transmission type” means that the light modulation device transmits light, such as a transmission type liquid crystal display device, and “reflection type” means a reflection type liquid crystal display device or the like. This means that the light modulation device reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(5) In the above embodiment, an example in which a liquid crystal light modulation device is used as the light modulation device has been described. However, the present invention is not limited to this. In general, the light modulation device only needs to modulate incident light in accordance with an image signal, and a light valve, a micromirror light modulation device, or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(6) The present invention can be applied to a front projection type projector that projects from the side that observes the projected image, or to a rear projection type projector that projects from the side opposite to the side that observes the projected image. It is.

DESCRIPTION OF SYMBOLS 1 ... Light source device, 11a ... Solid light source, 30R, 30G, 30B ... Liquid crystal light modulator, 50 ... Projection optical system, 71R, 71G, 71B ... Liquid crystal light modulator, 73 ... Projection optical system, B1-B4 ... Block, B11 to B14 block, B21 to B26 block, D drive device, D1 to D4 drive circuit, PJ1, PJ2 projector, SCR screen, T1 to T4 temperature sensor

Claims (9)

A plurality of solid-state light sources divided into a plurality of blocks according to a temperature distribution generated when driven with a constant current,
A light source device comprising: a drive device that drives the plurality of solid-state light sources by changing a drive current for each of the blocks so that the temperature distribution is uniform.   The drive device changes the drive current for each block so that the same light amount as a reference light amount, which is a light amount of light emitted when the plurality of solid state light sources are driven with the constant current, is obtained. The light source device according to claim 1.   The driving device reduces the driving current of at least one block located in a portion where the temperature of the temperature distribution generated when the plurality of solid-state light sources are driven with the constant current is highest than the constant current. The light source device according to claim 2.   The drive device uses at least one drive current of a block other than the block obtained by reducing the drive current of the block from the constant current so that the temperature distribution is uniform and the reference light amount is obtained. The light source device according to claim 3, wherein the light source device is also increased.   The said drive device is provided corresponding to each of the said block, and is provided with the some drive circuit which drives the said solid light source contained in a corresponding block, The any one of Claims 1-4 characterized by the above-mentioned. The light source device according to item. A temperature sensor provided for each block;
The light source device according to any one of claims 1 to 5, wherein the drive device changes a drive current for each block with reference to a detection result of the temperature sensor.   The light source device according to any one of claims 1 to 6, wherein the plurality of solid-state light sources are divided so that the same number is included in each of the plurality of blocks.   The light source device according to any one of claims 1 to 7, wherein the plurality of solid light sources are arranged in a linear shape or a planar shape. In a projector comprising a light source device, a light modulation device that modulates light from the light source device, and a projection optical system that projects light modulated by the light modulation device onto a screen,
A projector comprising the light source device according to claim 1 as the light source device.

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