JP2008177020A - Light source device, image display device, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device capable of eliminating nonuniformity of its luminous energy even though it uses LEDs having luminance irregularity in each single element or between elements adjacent to each other; an image display device, and a projector. <P>SOLUTION: In this light source device, a plurality of LEDs each having a light emission surface related to at least a radial direction in the vicinity of a rotation center of a rotatably journaled light source board are arranged. The light source device is provided with a motor 2 rotating the light source board, and a forced air-cooling means capable of forcibly air-cooling the light source board with the rotation of the motor 2. The light source device is also provided with a fan 32 arranged as the forced air-cooling means, and a reverse rotation means rotating the light source board in a reverse direction. The light source device is still also provided with a power-supplying slip ring 8 or a rotary transformer between the side of a fixed part journaling the light source board and the side of a rotation part including the light source board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source device, an image display device, and a projector.

  In recent years, as the demand for miniaturization of projectors has increased, light source devices, image display devices, and projectors using this LED light source have been studied with the increase in output of light emitting diodes (LEDs). Since the LED can be downsized and the number of components can be reduced, it has great potential as a next-generation display element.

  By the way, in order to individually adjust the variation of each LED element, a matrix type drive is required. In addition, in an LED drive device for lighting applications where the power of each LED is large, an LSI for driving a large power has not been created yet, and it is disadvantageous in terms of cost. Although it is considered to be used, it is difficult to adjust the luminance variation of individual LEDs in the series connection type.

  Therefore, when driving a plurality of elements connected in series, for example, LEDs, at a constant current, a constant current driving device capable of individually adjusting the luminance variation of each LED element is driven by this constant current driving device. A backlight light source device and a color liquid crystal display device are known (see, for example, Patent Document 1).

  On the other hand, driving of a light source used in an RGB field sequential color display projector is performed by switching on / off a LED driven with a large current at high speed. Further, since the LED is used by pulse driving, it is driven at a current value larger than the rated current value. Therefore, the difference of the forward voltage Vf in each of the R, G, and B LEDs becomes larger, and the energy utilization efficiency is lowered unless the drive voltage value for driving the load LED is switched greatly.

  On the other hand, when the LED is driven by the LED power supply circuit, the driving state immediately after switching the lighting LED is determined by the fact that the control method is feedback control and the response of the DC-DC converter is delayed. A delay time occurs before the constant current state is reached. The light emission amount of the LED in this delay period is different from that in the case of the predetermined constant current drive, and appears as non-uniform light amount in the LED light emission period. In particular, it is not suitable for a display device that expresses gradation by pulse width modulation (PWM) control based on the uniform light quantity of the illumination light source.

  In order to eliminate unevenness in the amount of light within the LED emission period, even if the LED driven with a large current is switched on at high speed, the LED can be stably emitted with a predetermined emission amount, and energy can be used. A highly efficient drive device was needed. Therefore, as a display device using a rod operation type illumination unit using a plurality of LEDs using a rotation drive device, it is configured with an L-shaped optical surface attached to a rod holder which is a rotatable holder. Two square light guide rod members are rotated by a motor as a movable means, and a plurality of LEDs as light emitters arranged on the inner periphery of a light source substrate formed in a drum shape are provided for each light guide rod member. One or two, which are sequentially turned on in accordance with the rotation of the light guide rod member, are known.

In this way, a plurality of LEDs are sequentially switched to emit pulses, and the relative positional relationship with the light guide rod member that takes in the radiated light is changed in accordance with the light emission switching of the LEDs, thereby effectively changing the brightness. An apparatus has been devised in which an LED is obtained and light with improved parallelism with a large amount of light is obtained from a light guide rod member (see, for example, Patent Document 2).
Japanese Patent Laying-Open No. 2005-310996 (paragraph 0011, FIG. 11) Japanese Unexamined Patent Publication No. 2004-311635 (paragraphs 0119 to 0124, FIGS. 19 and 20)

  However, regarding LEDs capable of obtaining high brightness with a large current, cost reduction has not been pursued by making it possible to positively adopt non-selected products. That is, it is possible to provide a light source device, an image display device, and a projector that can eliminate unevenness in the amount of light even though the LEDs have a luminance variation within a single element or between adjacent elements due to low quality. Another object of the present invention is to provide a heat dissipation measure for a high-power LED with a large current, and to improve low vibration and quietness.

In order to achieve the above object, the present invention provides the following means.
The light source device of the present invention is characterized in that a plurality of LEDs having at least a light emitting surface in the radial direction are arranged in the vicinity of the rotation center of a light source substrate rotatably supported.
According to the light source device of the present invention, since the light emitting surface in the radial direction is rotated to be uniformed into a disk shape, even a low-quality LED having a variation in luminance can be employed without selection. Cost reduction is possible.

In addition, the light source device of the present invention preferably includes a motor that rotates the light source substrate, and a forced air cooling unit that can forcibly cool the light source substrate as the motor rotates.
According to the light source device of the present invention, the mechanism in which the light source substrate is rotated by the motor and the forced air cooling means forcibly air-cools the light source substrate along with the rotation is simple and low-cost, and the LED that generates heat is efficiently forced. Air cooling is possible.

The light source device of the present invention preferably further includes a reverse rotation means for rotating the fan disposed as the forced air cooling means and the light source substrate in the reverse direction.
Further, according to the light source device of the present invention, if the fan and the light source substrate are rotated in the reverse direction by the reverse rotation means constituted by, for example, a planetary gear or the like, the vibration is canceled to some extent, so that the vibration and quietness are reduced. Is possible.

The light source device of the present invention preferably further includes a slip ring or a rotary transformer for supplying power between a fixed portion side that supports the light source substrate and a rotating portion side that includes the light source substrate.
According to the light source device of the present invention, power can be supplied through the slip ring or the rotary transformer from the fixed portion to the LED rotating as a part of the rotating portion pivotally supported by the fixed portion. Since the transformer is non-contact, there is no wear, so there is no need for maintenance and a long service life.

  Further, according to the light source device of the present invention, the light source substrate includes the LEDs having the number of colors capable of constituting at least three primary colors and the slip ring or the rotary transformer having the number of poles independently controllable according to the number of colors. It is also preferable that the rotation speed is higher than the speed synchronized with the frame period of the RGB field sequential color display.

  Further, according to the light source device of the present invention, the LEDs having different colors can be supplied to each LED from the slip ring or the rotary transformer having the number of poles that can independently control the LEDs constituting the three primary colors. If luminance control is performed for each LED, RGB field sequential color display can be supported. Further, when the rotation speed of the light source substrate is equal to or higher than the speed synchronized with the frame period of the RGB field sequential color display, it is possible to make the light emission unevenness inconspicuous.

In the light source device of the present invention, as the forced air cooling means, it is preferable that a casing is provided on the fixed portion to provide a ventilation path, and the casing also serves as an optical component.
According to the light source device of the present invention, a taper rod or the like which is an optical component can be used also as a casing of the light source device, and the casing serves as an effective ventilation path as a forced air cooling means, so that the cooling effect is enhanced.

  Further, when the light source device of the present invention is applied to an image display device, a simple, small, lightweight, power saving, and low heat generating device can be provided. It is particularly suitable for a projector.

  Hereinafter, an embodiment in which a light source device E according to the present invention or the light source device E is applied to an image display device or a projector will be described with reference to the drawings. In the following drawings, the same functions are denoted by the same reference numerals and description thereof is omitted.

  FIG. 1 is a side view showing a light source device E according to an embodiment of the present invention (hereinafter also referred to as “this embodiment”). As shown in FIG. 1, the light source substrate 1 is pivotally supported by a rotating shaft 4 in a fixed portion 6. The rotating shaft 4 is rotationally driven by the motor 2 at a predetermined speed. A plurality of light-emitting diodes (LEDs) each having a square thin plate unit (square plate shape) having a light emission width from the vicinity of the rotation center to the radial direction are disposed on the light source substrate 1 (see FIGS. 2 and 9).

  This LED is fed by a circuit configuration described below. That is, the LED lighting current supplied from the LED lighting circuits 10 and 10 ′ (see FIGS. 4, 10, and 11) on the fixed unit 6 is supplied to the brush 82 disposed on the fixed unit 6. On the other hand, a slip ring 8 that is in sliding contact with the brush 82 is disposed in the rotating portion 7. An LED is attached to the light source substrate 1 that rotates integrally with the rotating unit 7, and a circuit is configured such that power is supplied to the LED from the slip ring 8 through the wire 81 (FIG. 3).

  That is, the LED lighting current is supplied from the LED lighting circuits 10 and 10 ′ on the fixed unit 6 to the LEDs on the rotating unit 7 through the brush 82 and the slip ring 8. As one of the forced air cooling means 3 which is a countermeasure against heat generation of the LED, a sword mountain-shaped heat radiation fin 31 (see FIG. 2) is disposed on the back surface of the light source substrate 1. The width (unit width) of the single LED in the light source device E is uniformed into a disk shape and becomes a good light source when the light emitting surface of the square plate LED continuous at least in the radial direction rotates. As a result, even a low-quality LED having a variation in luminance can be employed without selection, so that the cost can be reduced.

  FIG. 2 is an explanatory view of the light source substrate 1 in the light source device according to the present embodiment, (a) a front view and (b) a rear view. As shown in the front view of FIG. 2A, square plate-like LEDs are arranged on the surface of the light source substrate 1 with their diagonal lines aligned in the radial direction from the vicinity of the rotation center. The square plate-like LED used in this embodiment needs to be cooled because it generates a considerable amount of heat when outputting high luminance with a large current. Therefore, as the forced air cooling means 3 also shown in the rear view of FIG. 2B, the heat radiation fins 31 (see FIG. 1) with improved heat radiation efficiency are disposed on the rear surface of the light source substrate 1.

  The forced air cooling means 3 is configured to be capable of forced air cooling of the light source substrate 1 as the motor 2 that rotates the light source substrate 1 rotates. Then, the light source substrate 1 rotates and ventilates through the heat radiation fins 31 that rotate integrally. By forcibly air-cooling in this way, the light source device E is maintained at a specified temperature or lower, and thermal destruction is prevented. That is, the mechanism in which the light source substrate 1 is rotated by the motor 2 and the forced air cooling means 3 forcibly air cools the light source substrate 1 with the rotation of the light source substrate 1 is simple and low-cost, and can efficiently and efficiently cool the LEDs that generate heat. .

FIG. 3 is a longitudinal sectional view in which a main part of the rotating unit 7 of the light source device E according to the present embodiment is cut.
FIG. 4 is an explanatory diagram of the slip ring 8 in the light source device E according to the present embodiment. FIG. 5 is a side view of the main part of the light source device E according to the present embodiment. As shown in FIGS. 4 to 5, an LED lighting current supplied from the LED lighting circuit 10 is supplied to the brush 82 disposed in the fixed portion 6 and is in sliding contact with the slip ring 8.

  The slip ring 8 is disposed on the rotating shaft 4 constituting the rotating unit 7. As shown in FIGS. 3 to 4, the LED lighting current is passed from the slip ring 8 through the wire 81 to the LED on the light source substrate 1 that is a part of the same rotating unit 7 and rotates integrally with the slip ring 8. Wiring is connected so that power is supplied.

  FIG. 6 is an enlarged longitudinal sectional view of the planetary gear unit 5 in the light source device E according to the present embodiment, and (a) a longitudinal sectional view and (b) a front sectional view. As shown in FIG. 6, the driving force of the motor 2 (FIGS. 1 and 5) is received from one end of the drive shaft 41, and the light source substrate 1 attached to the other end of the drive shaft 41 is directly driven to rotate. The planetary gear unit 5 is engaged in the middle of the drive shaft 41.

  Inside the planetary gear portion 5, four planetary gear shafts 61 parallel to the drive shaft 41 are implanted in the fixed portion 6 independent of the drive shaft 41. As shown in FIG. 6B, the fan gear 52 that meshes with the periphery of the planetary gear shaft 61 supported by the planetary gear shaft 61 rotates in the opposite direction to the drive shaft 41, as shown in FIG. Is rotated clockwise. The fan 32 constitutes forced air cooling means 3 that blows air to the light source substrate 1 and performs forced air cooling.

  FIG. 7 is an enlarged vertical sectional view in which the planetary gear portion 5 ′ in the light source device E according to the present embodiment is partially modified, and (a) a vertical sectional view and (b) a front sectional view. As shown in FIG. 7, the driving force of the motor 2 (FIGS. 1 and 5) is received from one end of the driving shaft 42, and the fan 32 mounted directly in the middle of the driving shaft 42 is rotationally driven counterclockwise.

  A planetary gear portion 5 ′ is engaged with the other end of the drive shaft 42. Inside the planetary gear portion 5 ′, four planetary gear shafts 61 ′ parallel to the drive shaft 42 are implanted in the fixed portion 6 independent of the drive shaft 41. As shown in FIG. 7B, the light source board gear 52 'meshed with the periphery of the planetary gear shaft 61' through the planetary gear 51 'is supported in the opposite direction to the drive shaft 42. Rotate to. The light source substrate 1 is attached to the tip of a shaft 43 extending to the light source substrate gear 52 'and is driven to rotate clockwise.

  The planetary gear sections 5 and 5 'shown in FIGS. 6 and 7 constitute the reverse rotation means 5, and the fan 32 and the light source board 1 arranged as the forced air cooling means 3 are rotated in the reverse direction to thereby generate vibration. Since it cancels to some extent, the light source device E with low vibration can be provided. The rotation ratio between the fan 32 and the light source substrate 1 can be set as appropriate. The light source substrate 1 can be rotated at high speed in the case of FIG. 6, and the fan 32 can be rotated at high speed in the case of FIG.

  FIG. 8 is a longitudinal sectional view in which a part of the light source device E according to the present embodiment is cut. As shown in FIG. 8, a casing 90 is provided on the fixed portion 6 of the light source device E to provide a ventilation path, and the casing 90 also serves as an optical component 91 to enhance product completion. Since the casing 90 is provided with the ventilation paths 31, 32, and 33, it functions effectively as the forced air cooling means 3 together with the air blowing function of the fan 32. The optical component 91 is preferably a tapered rod or the like.

  FIG. 9 is an explanatory diagram in which LEDs are arranged on the front surface of the light source substrate 1 in the light source device E according to the present embodiment, and illustrates the case of (a) using three and (b) using six. The arrangement of the three-use LED in the square thin plate unit (square plate) shown in FIG. 9A is different from the arrangement of the four-use square plate LED shown in FIG. Although the area occupied by the effective light emitting surface whose rotation center is in the radial direction is not uniform, the uniformity can be improved by rotating the light source substrate 1. The arrangement of LEDs using six square plates as shown in FIG. 9B can also increase the uniformity by rotating the light source substrate 1.

  FIG. 10 is an explanatory diagram of the three primary color LEDs and the corresponding slip rings in the light source device according to the present embodiment. As shown in FIG. 10, the green light emission current for emitting green light is supplied from the LED lighting circuit 10 ′ to the brush 82G disposed in the fixed portion 6. The green light emission current is supplied to the anode of the LED-G that emits green light through the slip ring 8G that is in sliding contact with the brush 82G, and the LED is turned on from the cathode of the LED-G through the slip ring 8C through the brush 82C. The circuit is configured to return to the circuit 10 '.

  Similarly, a blue light emission current for emitting blue light is supplied from the LED lighting circuit 10 ′ to the brush 82 </ b> B disposed in the fixed portion 6. This blue light emission current is supplied to the anode of LED-B that emits blue light through the slip ring 8B that is in sliding contact with the brush 82B, and the LED is turned on from the cathode of LED-B via the slip ring 8C and the brush 82C. The circuit is configured to return to the circuit 10 '.

  Similarly, a red light emission current for causing red light emission is supplied from the LED lighting circuit 10 ′ to the brush 82 </ b> R disposed in the fixed portion 6. The red light emission current is supplied to the anode of the LED-R that emits red light through the slip ring 8R that is in sliding contact with the brush 82R, and the LED is turned on from the cathode of the LED-R through the brush 82C through the slip ring 8C. The circuit is configured to return to the circuit 10 '.

  In this way, the LED-G, B, R of the number of colors that can constitute at least three primary colors, the slip rings 8G, B, R of the number of poles that can be independently controlled according to the number of colors, or the rotary transformer T are provided. If the light source device E has a rotational speed of the light source substrate 1 that is equal to or higher than the speed synchronized with the frame period of the RGB field sequential color display, the LEDs constituting the three primary colors can be independently controlled by the LEDs having different numbers of colors. By supplying power to each LED from a number of the slip rings 8 or the rotary transformer T and controlling the luminance for each LED of different color, RGB field sequential color display can also be supported. Further, since the rotation speed of the light source substrate 1 is equal to or higher than the speed synchronized with the frame period of the RGB field sequential color display, the uneven light emission can be made inconspicuous.

  FIG. 11 is an explanatory diagram of the rotary transformer T in the light source device E according to the present embodiment. As shown in FIG. 11, the primary coil T <b> 1 of the rotary transformer T to which the LED lighting current is fed from the LED lighting circuit 10 is disposed on the fixed part 6 side that pivotally supports the light source substrate 1. On the other hand, the secondary coil T2 of the rotary transformer T is disposed in any of the rotating parts 7 so as to face and contact the primary coil T1.

  This rotary transformer T can transmit the LED lighting current from the LED lighting circuit 10 on the fixed portion 6 side in a non-contact state from the primary coil T1 to the secondary coil T2. Further, unlike the slip ring 8, the rotary transformer T is non-contact, so there is no wear, no maintenance is required, and the life is long.

  Then, by using the light source device E of the present invention as a light source for a backlight of a liquid crystal panel, a direct view type image display device can be configured. Furthermore, the light source device of the present invention can be applied to a projector.

  FIG. 12 is a block diagram of the main part of an embodiment in which the light source device E according to the present invention is applied to a liquid crystal projector P. The liquid crystal projector P shown in FIG. 12 employs the light source device E shown in FIG. Red light emitted from the light source device 101 that emits red light is incident on the red liquid crystal light valve 111 to form a red image, and green light emitted from the light source device 102 that emits green light is green liquid crystal light. A green image is formed by entering the bulb 112, and blue light emitted from the light source device 103 that emits blue light is incident on the blue liquid crystal light valve 113 to form a blue image.

  In the liquid crystal projector P, the red image, the green image, and the blue image are combined by the color combining prism 120 and projected onto the screen by the projection lens 130. At this time, light having a uniform light intensity distribution is emitted from the light source devices 101, 102, and 103, so that an image with excellent image quality can be obtained. Since the liquid crystal projector P does not require a color separation optical system that is necessary when a lamp is used as a light source, the projector can be miniaturized. Also, a digital micromirror device (DMD) can be used as the light valve. DMD is a trademark of Texas Instruments Incorporated. In the case of DMD application, the light source device of FIG. 10 provided with LED-R, LED-G, and LED-B is particularly suitable.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a side view which shows the light source device which concerns on embodiment (this embodiment) of this invention. It is explanatory drawing of the light source board | substrate in the light source device which concerns on this embodiment, (a) Front view, (b) It is a rear view. It is the longitudinal cross-sectional view which cut the principal part in the rotation part of the light source device which concerns on this embodiment. It is explanatory drawing of the slip ring in the light source device which concerns on this embodiment. It is a side view of the principal part in the light source device which concerns on this embodiment. FIG. 6 is an enlarged longitudinal sectional view of the planetary gear unit in the light source device according to the present embodiment, and (a) a longitudinal sectional view and (b) a front sectional view. It is the expansion longitudinal cross-sectional view which deform | transformed the planetary gear part in the light source device which concerns on this embodiment partially, (a) Longitudinal section (b) It is front sectional drawing. It is the longitudinal cross-sectional view which partly cut in the light source device which concerns on this embodiment. It is explanatory drawing which has arrange | positioned LED in the front surface of a light source board | substrate in the light source device which concerns on this embodiment, (a) 3 use (b) 6 use. It is explanatory drawing of 3 primary color LED in the light source device which concerns on this embodiment, and a slip ring corresponding to it. It is explanatory drawing of the rotary transformer in the light source device which concerns on this embodiment. It is a principal part block diagram of embodiment which applied the light source device which concerns on this invention to the liquid crystal projector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source board | substrate, 2 ... Motor, 3 ... Forced air cooling means, 32 ... Fan, 5 ... Reverse rotation means (planetary gear), 6 ... Fixed part, 7 ... Rotation part, 8 ... Slip ring, 90 ... Casing, 91 ... Optical parts (tapered rod), E ... light source device, T ... rotary transformer, P ... projector

Claims (8)

  A light source device comprising a plurality of LEDs each having a light emitting surface in the radial direction in the vicinity of a rotation center of a light source substrate rotatably supported. A motor for rotating the light source substrate;
The light source device according to claim 1, further comprising forced air cooling means capable of forced air cooling of the light source substrate in accordance with rotation of the motor.   The light source device according to claim 1, further comprising a reverse rotation unit configured to rotate the fan disposed as the forced air cooling unit and the light source substrate in a reverse direction.   4. A slip ring or a rotary transformer for power supply is provided between a fixed portion side supporting the light source substrate and a rotating portion side including the light source substrate. The light source device according to item. A number of LEDs capable of forming at least three primary colors;
The slip ring or the rotary transformer of the number of poles that can be independently controlled according to the number of color development,
The light source device according to claim 4, wherein the rotation speed of the light source substrate is equal to or higher than a speed synchronized with a frame period of RGB field sequential color display. As the forced air cooling means,
Applying a casing to the fixed part to provide a ventilation path,
The light source apparatus according to claim 2, wherein the casing also serves as an optical component.   An image display device comprising the light source device according to any one of claims 1 to 6.   A projector comprising the image display device according to claim 7.

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