JP2013057786A - Laser source device and image projection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser source device that allows the sufficient reduction of speckle noise, and to provide an image projection apparatus with which a projection image of reliably reduced sighting of speckle noise on a projection screen is obtained, and of which the laser source device has reduced failure rate.SOLUTION: The laser source device comprises: a laser source including a plurality of laser beam emitting units; lighting control means for causing the respective laser beam emitting units to light in a pulsed manner sequentially at a lighting repetition frequency of 15 Hz or more; and an optical member for condensing a laser beam emitted from the laser source and for emitting the condensed light. The laser beams emitted from the respective laser beam emitting units are condensed on the same position on an optical axis of the optical member. An image projection apparatus comprises the laser source device, and an integrator of which an optical axis is identical with the rotational axis of a reflection system, and of which an irradiated surface is disposed on a condensed position of reflected light from a second reflecting mirror.

Description

  The present invention relates to a laser light source device and an image projection device such as a projector device provided with the laser light source device.

  Currently, for example, a projector apparatus is widely used as an image projection apparatus using a liquid crystal panel or a DMD (registered trademark) element, but in recent years, development of a technique using a laser beam as a light source used in the projector apparatus. Is underway.

  However, when a laser light source device is used as a light source in the projector device, it is observed that a glaring flicker called “speckle noise” occurs on the screen. This phenomenon occurs when the image light is observed by projecting a laser beam, which is coherent light, onto a screen or the like, and the light in phase is interfered and the intensity of light is generated on the retina of the observer. .

  Various methods have been proposed so far for reducing speckle noise. For example, in Japanese Patent No. 4379482 of Patent Document 1, an optical path conversion unit that converts an optical path of laser light emitted from a laser light source and enters the superimposed illumination element is moved by a moving unit, and the laser light source device is transferred to the integrator. A method is described in which speckle noise is reduced by temporally changing the optical path to reach.

Japanese Patent No. 4379482

  However, in the method described in Patent Document 1, it is necessary to mechanically drive the optical path conversion means as the speckle reduction means, and the laser light source device itself is increased in size, and the durability of the drive unit is the same as that of the laser light source. There is a problem that it is shorter than the lifetime and increases the failure rate of the laser light source device.

  The present invention has been made based on the above circumstances, and a laser light source device capable of sufficiently reducing speckle noise, and a projection in which speckle noise on a projection screen is surely reduced. It is an object of the present invention to provide an image projection apparatus in which an image is obtained and the failure rate of the laser light source device is reduced.

The laser light source device of the present invention includes a laser light source having a plurality of laser light emitting portions, lighting control means for sequentially turning on each of the laser light emitting portions at a lighting repetition frequency of 15 Hz or more, and the laser. An optical member that condenses and emits laser light emitted from the light source;
The laser light emitted from each of the laser light emitting portions is condensed at the same position on the optical axis of the optical member.

  In the laser light source device of the present invention, a plurality of the laser light emitting portions are arranged so as to be aligned on the same plane perpendicular to the axis extending along the optical axis of the laser light emitted from the laser light source. Can do. In addition, the laser light emitting portion is configured to be arranged at a position on the same circumference around an axis extending along the optical axis of the laser light emitted from the laser light emitting portion. Is preferred.

In the laser light source device of the present invention, the laser light source includes a red laser light source that emits red laser light, a blue laser light source that emits blue laser light, and a green laser light source that emits green laser light. Including
It is preferable that the lighting control unit is configured to correspond to each of the red laser light source, the blue laser light source, and the green laser light source.

  Still further, in the laser light source device of the present invention, each of the laser beam emitting portions may be constituted by a laser element and a collimator lens that controls a spread angle of the laser beam emitted from the laser element. it can.

An image projection device of the present invention comprises the above laser light source device and an integrator that emits laser light incident from the laser light source device as light of uniform intensity,
The integrator is arranged such that the optical axis coincides with the optical axis of the optical member in the laser light source device, and the light incident surface is disposed at a position where the laser light emitted from the laser light source device is condensed. It is characterized by.

  According to the laser light source device of the present invention, each of the plurality of laser beam emitting units in the laser light source is sequentially turned on in a predetermined cycle by the lighting control means and emitted from each of the laser beam emitting units. Since the laser beam to be emitted is condensed at the same position on the optical axis of the optical member by the optical member, the incident direction of the emitted laser light is temporally relative to the condensing position. Will be changed. As a result, the interference pattern is averaged when the position of the interference pattern due to the laser light emitted from the laser light source device is shifted in time (multiple types of interference patterns different from each other are superimposed). Noise can be reliably reduced. In addition, since no mechanical drive mechanism is provided, the failure rate of the laser light source device can be reduced.

  Therefore, according to the projection device including the laser light source device, the speckle noise on the projection screen is reliably reduced, and the optical distance from the laser light source device to the integrator is a constant size. Therefore, it is possible to obtain a projection image in which a change in brightness is reduced without a temporal change in the light capture rate in the integrator.

It is explanatory drawing which shows the outline of a structure in an example of the projector apparatus which concerns on the image projector of this invention. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 1A, illustrating an outline of a configuration of an example of a laser light source that constitutes a laser light source device in the projector apparatus illustrated in FIG. 1. FIG. 3 is a conceptual diagram for explaining a method of lighting the laser light source shown in FIG. 2. It is a timing chart figure which shows the lighting control method of the laser light source shown in FIG. It is the (A) top view which shows the other structural example of the laser light source in the laser light source apparatus of this invention, (B) AA sectional view taken on the line in (A). It is the (A) top view which shows the further another structural example of the laser light source in the laser light source apparatus of this invention, (A) The sectional view on the AA line in (A). It is the (A) top view which shows the further another structural example of the laser light source in the laser light source apparatus of this invention, (A) The sectional view on the AA line in (A).

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is an explanatory diagram showing an outline of the configuration of an example of a projector apparatus according to an image projection apparatus of the present invention.
The projector device controls the laser light source device 10, the rod-shaped integrator 50 that emits laser light incident from the laser light source device 10 as light of uniform intensity, and the spread angle of the laser light emitted from the integrator 50. A collimator lens 51 that is incident on a spatial modulation element 52 such as DMD (registered trademark), and a projection lens 53 that enlarges and projects the image light modulated by the spatial modulation element 52 on the screen S. . The collimator lens 51 is arranged in a state where its optical axis coincides with the optical axis C _{I of the} integrator 50.

The laser light source device 10 includes a laser light emitting mechanism 20 having a plurality of laser light sources, a plurality of power supplies 26A, 26B, 26C and a plurality of lighting control means 27A, 27B, 27C corresponding to each laser light source, and laser light. A condensing lens 15 made of, for example, a convex lens is provided for condensing the laser light emitted from the emission mechanism 20 and entering the light incident surface 50A of the integrator 50. The condenser lens 15 is arranged in a state where its optical axis coincides with the optical axis C _{I of the} integrator 50.

The laser light emitting mechanism 20 includes a blue laser light source 21A that emits blue laser light (wavelength 460 nm), a green laser light source 21B that emits green laser light (wavelength 530 nm), and a red laser that emits red laser light (for example, wavelength 640 nm). The light source 21C, the plate-shaped first dichroic mirror 28A, and the plate-shaped second dichroic mirror, which are arranged at positions on the front side in the light emission direction of the respective laser light sources 21A, 21B, and 21C, have different wavelength selection characteristics. 28B and a plate-like third dichroic mirror 28C.
Each of the laser light sources 21A, 21B, and 21C is arranged, for example, so that the optical axes of the emitted laser light extend in parallel with each other, and each of the dichroic mirrors 28A, 28B, and 28C has a light emitting surface that is a laser light source. In a state inclined with respect to the optical axis of the laser beams emitted from 21A, 21B, and 21C, they are arranged in parallel with each other in the optical axis direction of the integrator lens 50.

As shown in FIG. 2, the blue laser light source 21 </ b> A includes a flat support substrate 25, and an axis (hereinafter, referred to as “laser light source optical axis”) extending perpendicularly to the support substrate 25 in the support substrate 25. .) A plurality (nine in this example) of laser light emitting portions 22A to 22I are arranged at positions arranged at equal intervals in the circumferential direction on the same circumference centered on C _L.
Each of the laser beam emitting units 22A to 22I includes a laser element 23 made of, for example, a semiconductor laser element, and a collimator lens 24 that controls the spread angle of the laser beam emitted from the laser element 23. in parallel to emit the optical axis C _L of the laser beam from the emitting portion 22A~22I for example a laser light source.
The blue laser light source 21A is set to the position the optical axis C _L of the laser light source is perpendicular to the optical axis C _I of the integrator 50, the optical axis C _L of the laser light source intersects the light emitting surface of the first dichroic mirror 28A, optical axis C _I of the integrator 50 is in a state where a position intersecting the light emitting surface of the third dichroic mirror 28C coincide, is arranged.

The lighting control means 27A related to the blue laser light source 21A performs ON / OFF control of the power feeding operation from the power supply 26A to the laser elements 23 of the respective laser beam emitting units 22A to 22I, thereby controlling the laser elements of the laser beam emitting units 22A to 22I. Each of 23 has a function of sequentially lighting in a pulse shape.
The repetition lighting frequency f of one laser element 23 is 15 Hz or more, for example, 100 Hz (see FIG. 4). The reason for this is as follows. That is, as the number of types of interference patterns (speckle patterns) displayed on the screen S increases during a predetermined time, speckle noise can be more difficult to be recognized by an observer. Since the eye viewing speed is about 1/15 second (15 Hz), the repetition lighting frequency of one laser element 23 is 15 Hz or more in relation to the number of laser elements 23 in the laser light source, that is, human This is because it is possible to reliably prevent the speckle noise from being visually recognized on the screen S by lighting at a lighting repetition frequency equal to or higher than the visual recognition speed. On the other hand, when the repetitive lighting frequency is lower than 15 Hz, the observer can add only a smaller pattern (for example, about six types with nine laser elements as in this embodiment), and the interference pattern is reduced. Since the number to be averaged is small, a sufficient effect cannot be obtained with respect to the number of laser elements to be used.
The lighting state holding time of one laser element 23 is 1/30 seconds at the longest. For example, in the case where two laser elements are alternately lit at a repetition frequency of 15 Hz, a speckle noise reduction effect can be obtained by maintaining the lit state for 1/30 second.

In this example, green laser light source 21B and the red laser light source 21C has the same configuration as the blue laser light source 21A, the green laser light source 21B, the optical axis C _L of the laser light source and the optical axis C _I of the integrator 50 orthogonal, the position where the optical axis C _L of the laser light source intersects the light exit surface of the second dichroic mirror 28B, a position where the optical axis C _I of the integrator 50 intersects the light exit surface of the second dichroic mirror 28C The red laser light source 21C is arranged such that the optical axis C _L of the laser light source is orthogonal to the optical axis C _{I of the} integrator 50, and the optical axis C _L of the laser light source is the third dichroic mirror 28C. In a state where the position intersecting with the light exit surface of the light source coincides with the position where the optical axis C _I of the integrator 50 intersects with the light exit surface of the third dichroic mirror 28C. Has been.
The lighting control means 27B related to the green laser light source 21B and the lighting control means 27C related to the red laser light source 21C have the same configuration as the lighting control means 27A related to the blue laser light source 21A.

In the projector device described above, the laser light emitted from the laser light emitting mechanism 20 in the laser light source device 10 is condensed by the condenser lens 15 and is incident on the light incident surface 50A of the integrator 50. More specifically, in the blue laser light source 21A in the laser light emitting mechanism 20, as shown in FIGS. 3A and 4A, the power supply 26A for the laser element 23 of the first laser light emitting unit 22A. By turning ON / OFF the power supply operation, the laser element 23 of the first laser beam emitting portion 22A is lit in a pulse shape. Next, as shown in FIGS. 3B and 4B, the power supply to the laser element 23 of the first laser beam emitting unit 22A is turned off and the second laser beam emitting unit 22B is turned off at the same time. The power supply operation from the power source 26A to the laser element 23 of the second laser light emitting unit 22B is ON / OFF controlled so that the laser element 23 of the second laser light emitting unit 22B is turned on. Is lit in pulses. Further, each of the third laser light emitting part 22C to the eighth laser light emitting part 22H is also sequentially subjected to the laser element 23 similarly to the first laser light emitting part 22A and the second laser light emitting part 22B. Is turned on in a pulse shape, and thereafter, as shown in FIGS. 3 (I) and 4 (I), the power supply to the laser element 23 of the eighth laser beam emitting portion 22H is turned off and turned off simultaneously ( FIG. 4 (H)) The power supply operation from the power source 26A to the laser element 23 of the ninth laser light emitting part 22I is ON / OFF controlled so that the laser element 23 of the ninth laser light emitting part 22I is turned on. As a result, the laser element 23 of the ninth laser beam emitting portion 22I is turned on in pulses. In this way, the power supply operation from the power source 26A to the laser elements 23 of the respective laser beam emitting units 22A to 22I is ON / OFF controlled by the lighting control means, whereby the laser elements 23 of the respective laser beam emitting units 22A to 22I. Are sequentially turned on in pulses. In this example, as shown in FIG. 4 (J), the light pulses from the laser elements 23 in the respective laser light emitting portions 22A to 22I are temporally continuous, and a constant output is obtained as a whole of the blue laser light source 21. The laser elements 23 of the respective laser beam emitting portions 22A to 22I are controlled to be turned on.
In the green laser light source 21B and the red laser light source 21C, the same lighting control as that of the blue laser light source 21 is performed by the lighting control means 27B and 27C. Here, in each of the laser light sources 21A, 21B, and 21C, the laser elements 23 in the laser light emitting portions at positions where the incident directions of the laser light to the integrator 50 are the same do not necessarily have to be turned on simultaneously.

  Then, the blue laser light emitted from the blue laser light source 21A is reflected by the first dichroic mirror 28A, and the reflected light passes through the second dichroic mirror 28B, and the green light emitted from the green laser light source 21B. The reflected light reflected by the second dichroic mirror 28B is combined, and the combined light of the blue laser light and the green laser light combined by the second dichroic mirror 28B is transmitted through the third dichroic mirror 28C. The transmitted light is combined with the reflected light of the red laser light emitted from the red laser light source 21C and reflected by the third dichroic mirror 28C, and emitted.

The light emitted from the laser light emitting mechanism 20 (indicated by a two-dot chain line in FIG. 1) is maintained by the condenser lens 15 at an incident angle with respect to the light incident surface 50A of the integrator 50, for example, at a constant magnitude. only the incident direction with respect to the light incident surface 50A of the integrator 50 is in a state of being changed over time, is incident is condensed at a position on the optical axis C _I in the light incident surface 50A of the integrator 50.
The laser light whose intensity is made uniform by the integrator 50 is emitted at the same emission angle as the incident angle with respect to the integrator 50, and the image light formed by being modulated by the spatial modulation element 52 is passed through the projection lens 53. Is enlarged and projected on the screen S.

Thus, according to the laser light source device 10 configured as described above, each of the plurality of laser light emitting portions 22A to 22I located in the same plane in each of the laser light sources 21A, 21B, and 21C is turned on by the lighting control means 27A and 27B. sequentially while being turned pulsed at a predetermined cycle by 27C, a laser beam emitted from each laser light emitting portion 22A~22I is on the optical axis C _I of the condenser lens 15 by the condenser lens 15 Since the laser beams emitted from the respective laser light sources 21A, 21B, and 21C are configured to be focused at the same position, the incident direction with respect to the focused position is temporally changed so that the light from the integrator 50 is emitted. The light enters the incident surface 50A. As a result, the interference pattern is averaged by shifting the position of the interference pattern formed on the screen S in time (a plurality of different interference patterns are superimposed on each other), so that speckle noise can be reliably ensured. Can be extinct. In addition, since there is no mechanical drive mechanism, the failure rate of the apparatus can be reduced.

  Therefore, according to the projector device provided with the laser light source device 10, the speckle noise on the screen S can be surely reduced and the mechanical drive mechanism is not provided, so that the failure rate of the device can be reduced. Can do.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, it is not necessary that all of the blue laser light source, the green laser light source, and the red laser light source have the configuration according to the above-described embodiment (the configuration that includes the lighting control unit), and at least one laser light source has the above-described implementation. If it has the structure which concerns on a form, the speckle noise reduction effect can be acquired.
Further, it is not always necessary for the laser light source to be controlled so that the light pulses of the respective laser elements are continuous in time.
Furthermore, the configuration of the laser light source is not limited to that according to the above embodiment. For example, the number of laser light emitting portions (the number of laser elements) may be two or more, and the light sources are installed on the same plane. There is no need to

Furthermore, as shown in FIG. 5, the laser light source 21 has an axis (optical axis of the laser light source) C _{L in} which a plurality of laser light emitting portions 22 extend perpendicularly to the support substrate 25 in the flat support substrate 25. It may be configured to be arranged at positions that are different from each other in the center and are arranged at intervals of equal angular intervals. In this laser light source 21, two adjacent laser beam emitting portions 22 positioned on different circumferences are made into one group, and the laser element 23 is sequentially turned on at a predetermined lighting repetition frequency for each group 221 to 229. Lights up in pulses at 15 Hz or higher. In the configuration using such a laser light source 21, the above speckle reduction effect can be obtained more reliably, and the laser beam can be emitted with high intensity.

Furthermore, as shown in FIG. 6, the laser light source 21 has a configuration in which a plurality (nine in this example) of laser light emitting portions 22 </ b> A to 22 </ b> I are two-dimensionally arranged in an array (aligned vertically and horizontally). It may be said. In the laser light source 21, the incident angle of the laser light emitted from each of the laser light emitting portions 22 </ b> A to 22 </ b> I with respect to the light incident surface of the integrator is set in a range of, for example, 0 ° to 25 °.
Even in the configuration including such a laser light source 21, the power supply operation from the power source 26A to the laser elements 23 of the respective laser beam emitting portions 22A to 22I is controlled to be turned on, similarly to the laser light source having the configuration shown in FIG. By the ON / OFF control by the means, the laser elements 23 of the respective laser beam emitting units 22A to 22I are sequentially turned on in a pulse shape. For example, the light pulses by the laser elements 23 in the respective laser beam emitting units 22A to 22I are emitted. By controlling the lighting of the laser elements 23 of the respective laser beam emitting units 22A to 22I so as to obtain a constant output as a whole for the laser light source 21, the same effects as those according to the above embodiment are obtained. Is obtained.
Also in the laser light source 21 having such a configuration, as shown in FIG. 7, three laser light emitting portions arranged in one direction, for example, the horizontal direction (or may be the vertical direction) are made into one group. The laser element 23 may be configured to be lit in pulses at a predetermined lighting repetition frequency (15 Hz or higher) sequentially every 221 to 223.

DESCRIPTION OF SYMBOLS 10 Laser light source device 15 Condensing lens 20 Laser light emission mechanism 21 Laser light source 21A Blue laser light source 21B Green laser light source 21C Red laser light source 22, 22A-22I Laser light emission part 221-229 Group 23 Laser element 24 Collimator lens 25 Support substrate 26A, 26B, 26C Power supply 27A, 27B, 27C Lighting control means 28A First dichroic mirror 28B Second dichroic mirror 28C Third dichroic mirror 50 Integrator 50A Light incident surface 51 Collimator lens 52 Spatial modulation element 53 Projection lens C _L optical axis S screen of the optical axis C _I integrator of the laser light source

Claims (6)

A laser light source having a plurality of laser beam emitting units, lighting control means for sequentially lighting each of the laser beam emitting units in a pulsed manner at a lighting repetition frequency of 15 Hz or more, and a laser beam emitted from the laser light source An optical member that collects and emits light,
The laser light source apparatus characterized in that the laser light emitted from each of the laser light emitting portions is condensed at the same position on the optical axis of the optical member.   2. The laser according to claim 1, wherein a plurality of the laser beam emitting units are arranged so as to be aligned on the same plane perpendicular to an axis extending along an optical axis of the laser beam emitted from the laser light source. Light source device.   A plurality of the laser beam emitting units are arranged so as to be arranged at positions on the same circumference centering on an axis extending along the optical axis of the laser beam emitted from the laser beam emitting unit. Item 3. The laser light source device according to Item 2. The laser light source includes a red laser light source that emits red laser light, a blue laser light source that emits blue laser light, and a green laser light source that emits green laser light,
The laser light source according to any one of claims 1 to 3, wherein the lighting control means is provided corresponding to each of the red laser light source, the blue laser light source, and the green laser light source. apparatus.   Each of the said laser beam emitting part is comprised by the collimator lens which controls the spreading angle of the laser beam and the laser beam radiate | emitted from the said laser element. The laser light source device described. The laser light source device according to any one of claims 1 to 5 and an integrator that emits laser light incident from the laser light source device as light of uniform intensity,
The integrator is arranged such that the optical axis coincides with the optical axis of the optical member in the laser light source device, and the light incident surface is disposed at a position where the laser light emitted from the laser light source device is condensed. An image projection apparatus characterized by the above.

Images