JP2023119544A - Illumination device and projector - Google Patents

Abstract

To achieve miniaturization and high efficiency of an illumination device for a projector.SOLUTION: In an illumination device 1, an optical element 2 for composition reflects one of light beams F1 and F2 from two light sources LS1 and LS2, which are input from two directions, and transmits the other, and makes reflected light and transmitted light, which are converted in the same direction, incident to a light uniformizing element 3. The optical element 2 for composition is composed of a prism having four surfaces, one surface 2A of the four surfaces is a reflection surface for generating the reflected light, and two surfaces 2B and 2C facing each other are transmission surfaces for generating the transmitted light. The light beams F1 and F2 from the two light sources LS1 and LS2, which are incident to the reflection surface 2A and the transmission surfaces 2B and 2C of the optical element 2 for composition, are configured not to overlap on the optical element 2 for composition. The optical element 2 for composition is constituted separately from the light uniformizing element 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to lighting devices and projectors.

2. Description of the Related Art As a lighting device for a projector, there is already known a technique for realizing a compact, high-brightness lighting device by synthesizing outputs from two light sources.

Japanese Patent Application Laid-Open No. 2002-200001 discloses a configuration in which the end face of a rod integrator is made into a special shape to synthesize light from two light sources for the purpose of realizing a compact and high-brightness light source.
Patent Literature 2 discloses a configuration in which two light sources are arranged to face each other on both sides of the rod integrator in a direction perpendicular to the incident direction to the rod integrator.

In the conventional method such as Patent Document 1, since the rod integrator is provided with an incident surface directly, there is a problem that the cost increases because an inexpensive light tunnel cannot be used. In addition, since this method utilizes total reflection, there are restrictions on the angle of incidence of light rays, and the arrangement of light sources is restricted. In addition, since there is a spread angle of light rays from the light source, there is also a problem that the light rays that cannot be totally reflected in a realistic light source arrangement become losses, resulting in a decrease in efficiency.

In addition, in conventional methods such as those disclosed in Patent Document 2, the placement of the light source is symmetrical, which causes problems in terms of size and placement, and the position of the light source is close to the projection lens barrel, which is the heat-generating part. There's a problem.

An object of the present invention is to reduce the size and improve the efficiency of a lighting device for a projector.

In order to solve the above-described problems, an illumination device according to an aspect of the present invention includes two light sources, a synthesizing optical element for synthesizing two light beams output from the two light sources, and a light homogenizing element. , wherein the synthesizing optical element reflects one of the two light beams input from two directions and transmits the other light, and homogenizes the reflected light and the transmitted light converted in the same direction. The optical element for synthesis is composed of a prism having four or more multifaceted surfaces, one of the multifaceted surfaces is a reflecting surface for generating the reflected light, and the two surfaces are opposed to each other. is a transmission surface that generates the transmitted light, and the synthesis optical element is configured separately from the light homogenizing element, and the light rays incident on the reflection surface and the transmission surface of the synthesis optical element are , so as not to overlap on the combining optical element.

A lighting device for a projector can be made smaller and more efficient.

Schematic diagram showing an example of a lighting device according to an embodiment FIG. 11 is a diagram showing a first example of a lighting device configured to have two light sources with different structures; A diagram showing a second example of a lighting device configured to have two light sources with different structures. 1 is a schematic diagram showing a schematic configuration of a projector to which a lighting device according to an embodiment is applied; FIG. Schematic diagram showing a modified example of arrangement of projectors The figure which shows the 1st modification of an illuminating device FIG. 7 is a schematic diagram showing an example of the arrangement of the light homogenizing element and the color wheel in the illumination device shown in FIG. 6 ; The figure which shows the 2nd modification of an illuminating device The figure which shows the 3rd modification of an illuminating device The figure which shows the 3rd modification of an illuminating device An example of a condensed spot at the entrance of the light homogenizing element in the third modification A diagram showing the relationship between the synthesizing optical element and the light homogenizing element in the third modification and the planes of the two light sources

Embodiments will be described below with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements in each drawing are denoted by the same reference numerals as much as possible, and overlapping descriptions are omitted.

In the following description, the X direction and the Y direction are directions perpendicular to each other. The X and Y directions are typically horizontal. The X direction is the direction of incidence of light rays on the light homogenizing element 3 and the exit direction of light rays L from the light homogenizing element 3 . The Y direction is the optical axis direction of the light beam F1 output from the light source LS1.

FIG. 1 is a schematic diagram showing an example of a lighting device 1 according to an embodiment. The illumination device 1 is an element incorporated in the projector 50 (see FIG. 4) and used as the light source of the projector 50 . Note that the “projector” according to the present embodiment is a type of display device, and is a device that displays an image or video by projecting it on a large screen or the like, and uses DLP or liquid crystal to enlarge and project the image. It refers to a device that A "projector" may be called by other names, such as a projection device.

The illumination device 1 comprises two light sources LS 1 , LS 2 , a combining optical element 2 and a light homogenizing element 3 .

The two light sources LS1, LS2 output rays (fluorescence F1, F2). The two light sources LS1 and LS2 output light beams F1 and F2 in different optical axis directions. In the example of FIG. 1, the light sources LS1 and LS2 are arranged so that their optical axes are orthogonal. Also, the two light sources LS1 and LS2 are arranged so that the light beams F1 and F2 respectively output by them are input to the common combining optical element 2 .

The light source LS1 has a light emitting element 11, optical elements 12, 13, 14, 16, and 18, a reflective optical element 15, and a wavelength conversion element 17.

The light emitting element 11 is a light source that generates blue light, such as an LD (Laser Diode) or an LED (Light Emitting Diode). Although the configuration in which three light emitting elements 11 are provided side by side is illustrated in FIG.

The optical element 12 collimates the light generated by the light emitting element 11 and is formed integrally with or separately from the light emitting element 11 . The reflective optical element 15 is a simple mirror, and may be one having wavelength characteristics like a dichroic mirror, or a diffractive optical element like a DOE (Diffractive Optical Element).

The optical element 12, optical element 13, optical element 14, and reflective optical element 15 are arranged in series in this order along the optical axis direction of the light output from the light emitting element 11 (X positive direction in the example of FIG. 1). . The optical element 16 is arranged on the reflection direction side of the reflective optical element 15 (the Y negative direction side in the example of FIG. 1). The wavelength conversion element 17 is arranged on the Y negative direction side of the optical element 16 .

The optical elements 13 and 14, the reflective optical element 15, and the optical element 16 constitute a condensing optical system and form a light spot on the wavelength conversion element 17. FIG.

The wavelength conversion element 17 uses a phosphor to convert the blue light condensed into the light spot into yellow or yellow-green fluorescence, and emits it in the positive Y direction. Therefore, the light emitting element 11 is an excitation light source for outputting excitation light input to the wavelength conversion element 17 . Also, the light source LS1 outputs fluorescence F1 whose wavelength has been converted by the wavelength conversion element 17 .

The optical element 18 is arranged on the Y positive direction side of the optical element 16, so that the wavelength conversion element 17, the optical element 16, and the optical element 18 are arranged in the optical axis direction of fluorescence emitted by the wavelength conversion element 17 ( In the example, they are arranged in series in this order along the Y positive direction). With this configuration, the fluorescence F1 emitted from the wavelength conversion element 17 is guided to the synthesizing optical element 2 by the relay lens system composed of the optical elements 16 and 18 .

In addition, in the example of FIG. 1, the structure of the light source LS2 is the same as that of the light source LS1, so the description thereof is omitted. The light source LS2 also converts the blue light emitted from the light emitting element 11 into yellow or yellowish green fluorescence F2 by the wavelength conversion element 17 and outputs it toward the synthesis optical element 2 .

Thus, the two light sources LS1 and LS2 shown in FIG. Thereby, the illumination device 1 with high brightness can be realized.

The synthesizing optical element 2 is an element that synthesizes the lights F1 and F2 of the two light sources LS1 and LS2. In this embodiment, the synthesizing optical element 2 is a prism having four or more faces. One of the multiple surfaces of the prism is a reflective surface 2A, and two opposing surfaces are transmitting surfaces 2B and 2C.

The synthesizing optical element 2 synthesizes the light F1 from the light source LS1 by reflection and the light F2 from the light source LS2 by transmission, and guides it to the light homogenizing element 3 to combine the light F1 and F2 of the two light sources LS1 and LS2. realizes a lighting device that synthesizes

At least one of the transmitting surfaces 2B and 2C of the prism 2 may be a diffusing surface, and separate diffusing plates may be installed in front of and behind the prism 2. FIG. With this configuration, unevenness in color and luminance due to the output light F2 from the light source LS2 can be eliminated.

When the lights F1 and F2 synthesized by the synthesizing optical element 2 are input, the light homogenizing element 3 outputs light L obtained by homogenizing the illuminance and intensity distribution of these lights F1 and F2. In this embodiment, the light homogenizing element 3 is a light tunnel consisting of four-sided mirrors. By applying a relatively inexpensive light tunnel to the light homogenizing element 3, the cost of the illumination device 1 can be reduced. A rod-shaped glass rod integrator may be applied to the light uniformizing element 3 . Thereby, a highly efficient and high output lighting device can be realized. Other elements such as a plurality of fly-eye lenses may also be applied to the light homogenizing element 3 .

When a rod integrator is applied to the light homogenizing element 3, it is possible to output light L with high efficiency and high output compared to a light tunnel. However, since the rod integrator uses total internal reflection of light to homogenize the light, the light incident on the light homogenizing element 3 is totally reflected at the angle of incidence on the light homogenizing element 3. There is a constraint that it must be within the possible range. Therefore, the arrangement of the light sources LS1, LS2 with respect to the light homogenizing element 3 is also restricted to satisfy this condition.

On the other hand, when a light tunnel is applied to the light homogenizing element 3, it is not necessary to use total reflection as in the rod integrator, and the light beams F1 and F2 are synthesized by the reflecting surface 2A and the transmitting surfaces 2B and 2C of the prism 2. Therefore, the two light sources LS1 and LS2 can be arranged with respect to the light uniformizing element 3 without being subject to the restriction of the total reflection angle, which was a problem in the conventional methods described in Patent Documents 1 and 2. Therefore, the size of the illumination device 1 can be reduced.

In this embodiment, the synthesizing optical element (prism) 2 is configured separately from the light homogenizing element 3 . In the conventional methods such as Patent Documents 1 and 2, a relatively expensive rod integrator is applied as the light homogenizing element 3, and an element corresponding to the combining optical element 2 is integrally formed with the rod integrator. It is difficult to apply other elements, such as light tunnels, which are relatively inexpensive for homogenization elements. On the other hand, in the present embodiment, the synthesizing optical element 2 is separate from the light homogenizing element 3, so a relatively inexpensive element other than the rod integrator can be easily applied to the light homogenizing element 3. For example, the degree of freedom in device design can be improved, and cost reduction can be achieved.

Further, in this embodiment, one of the light beams F1 from the two light sources LS1 and LS2 is input to the light homogenizing element 3 as reflected light and the other F2 as transmitted light. Therefore, the angle formed by the optical axes of the two light beams F1 and F2 should be at least less than 180 degrees, preferably 90 degrees. As a result, the two light sources LS1 and LS2 are brought closer to each other than the configuration in which the two light sources are arranged in a straight line to face each other and the reflected light of both light rays is input to the light uniformizing element as in Patent Document 2. As a result, the space of the lighting device 1 can be reduced, so that the size of the device can be reduced.

Further, in this embodiment, the synthesizing optical element 2 is composed of a prism having four surfaces. is a transmission surface that generates transmitted light, and the light beams F1 and F2 from the two light sources LS1 and LS2 incident on the reflection surface 2A and the transmission surfaces 2B and 2C of the synthesis optical element 2 are projected onto the synthesis optical element 2 as configured so that they do not overlap. As a result, the two light beams F1 and F2 can be combined without loss and input to the light homogenizing element 3, so that the output light L can be made highly efficient. Therefore, in this embodiment, the illumination device 1 for projectors can be made compact and highly efficient.

Further, in the present embodiment, one of the two light sources, LS1, is arranged so that the optical axis of the light beam F1 is in the direction of incidence on the light homogenizing element 3 (and the emission direction of the light L from the light homogenizing element 3 shown in FIG. 1). direction) at 90 degrees. The two light sources LS1 and LS2 are arranged so that the optical axes of the light beams F1 and F2 output from the two light sources form an angle of 90 degrees.

With this configuration, as shown in FIG. 1, one light source LS2 is arranged on the incident direction side (X negative direction side) to the light homogenizing element 3, and the other light source LS1 is arranged on the side perpendicular to the incident direction ( Y negative direction side). As a result, the distance between the two light sources LS1 and LS2 can be reduced compared to a configuration in which two light sources are arranged in a straight line to face each other and the reflected light of both light rays is input to the light uniformizing element, for example, as in Patent Document 2. You can definitely get close. As a result, the installation space of the lighting device 1 can be reduced, so that the lighting device 1 can be further miniaturized.

The term "90 degrees" used here means a predetermined range including an angle of 90 degrees (for example, a range that increases or decreases by several degrees from 90 degrees). In the case of an angle of 90 degrees, there is a characteristic of preserving the spread angle of the light. "90 degrees" in the present embodiment includes an angle range that can achieve the same characteristics as in the case of 90 degrees.

In this embodiment, the light F1 output from one light source LS1 is input to the light uniformizing element 3 as reflected light by the synthesizing optical element 2, and the light F2 output from the other light source LS2 is the synthesizing optical element. It is sufficient that the light is input to the light uniformizing element 3 as transmitted light by the element 2, and the angle formed by the two light sources LS1 and LS2 may be other than 90 degrees. Similarly, the angle formed by the light source LS1 input to the light homogenizing element 3 as reflected light and the direction of incidence on the light homogenizing element 3 may be other than 90 degrees. However, if the angle formed by each is set to 90 degrees as shown in FIG. 1, it is possible to easily design the shape of the prism of the synthesizing optical element 2 and arrange the light sources LS1 and LS2.

In the example of FIG. 1, the two light sources LS1 and LS2 have the same structure, but the two light sources may have different structures. FIG. 2 is a diagram showing a first example 1A of a lighting device having two light sources with different structures.

In the example of FIG. 2, the structure of the light source LS1 is the same as the light source LS1 of FIG. On the other hand, the light source LS2 has a light emitting element 21, an optical element 22, and an optical element . The light emitting element 21 and the optical element 22 have the same configurations as the light emitting element 11 and the optical element 12 of the light source LS1. However, although the light emitting element 21 is a light source such as an LD or LED that generates light, the wavelength of the output light is assumed to be longer than the wavelength of the light emitting element 11 of the excitation light source used for the light source LS1.

The light-emitting element 21 is arranged to face the transmission surfaces 2B and 2C of the synthesizing optical element 2, and is arranged so that the optical axis direction of output light and the positive X direction. Also, the light emitting element 21, the optical element 22, and the optical element 23 are arranged in series in this order along the optical axis direction of the light output from the light emitting element 21 (X positive direction in the example of FIG. 2).

The optical element 23 functions as a condensing optical system that guides the light beam from the light emitting element 21 to the synthesizing optical element 2 .

Thus, in the illumination device 1A shown in FIG. 2, the wavelength conversion element 17 is not provided in the light source LS2. Therefore, the light F1 output from the light source LS1 is obtained by converting the blue light output from the light emitting element 11 into yellow or yellow-green fluorescence by the wavelength conversion element 17, whereas the light F1 output from the light source LS2 The output light F2 is not subjected to wavelength conversion and remains as the light output from the light emitting element 21 .

That is, in the illumination device 1A shown in FIG. 2, the two light sources LS1 and LS2 to be synthesized can have different spectra. The spectrum is the light emission characteristic of a light source represented by the intensity of light with respect to the wavelength. or color) are different. As described above, the spectrums of the output lights F1 and F2 from the two light sources LS1 and LS2 synthesized by the synthesizing optical element 2 are different, so that a lighting device with high color rendering can be realized.

In addition, in the illumination device 1A shown in FIG. 2, the structures of the two light sources LS1 and LS2 may be interchanged. That is, in contrast to the configuration shown in FIG. 2, the light source LS1 may include the excitation light source 21 and not the wavelength conversion element 17, and the light source LS2 may include the excitation light source 11 and the wavelength conversion element 17.

FIG. 3 is a diagram showing a second example 1B of a lighting device having two light sources with different structures. In the example of FIG. 3, the structure of the light source LS1 is the same as the light source LS1 of FIGS. 1 and 2, and has a single excitation light source LD1 (light emitting element 11, optical element 12). On the other hand, the light source LS2 has two solid-state light sources LD2 and LD3 inside.

The solid-state light source LD2 has a light-emitting element 31 and an optical element 32. As shown in FIG. The light source LS2 has an optical element 33 and a reflective optical element . The light emitting element 31, the optical element 32, and the optical element 33 have the same configuration as the light emitting element 21, the optical element 22, and the optical element 23 in FIG. 2, and are arranged in the same manner. The reflective optical element 34 is, for example, a dichroic mirror, which transmits light output from the solid-state light source LD2 and reflects light output from the solid-state light source LD3.

The light-emitting element 31, the optical element 32, the reflective optical element 34, and the optical element 33 are arranged in series in this order along the optical axis direction of the light output from the light-emitting element 31 (X positive direction in the example of FIG. 2). .

The solid-state light source LD3 has a light-emitting element 41 and an optical element . The light emitting element 41 is arranged to face the surface of the reflective optical element 34 on the side of the optical element 33, and is arranged so that the optical axis direction of the output light and the negative Y direction.

In the light source LS2, the light output from the solid-state light source LD2 is transmitted through the reflective optical element 34, and the light output from the solid-state light source LD3 is reflected by the reflective optical element 34 in the direction toward the combining optical element 2. , and incident on the transmission surface 2B of the optical element 2 for combining.

Thus, in the illumination device 1B shown in FIG. 3, the wavelength conversion element 17 is not provided in the light source LS2. Therefore, the light F1 output from the light source LS1 is obtained by converting the blue light output from the light emitting element 11 into yellow or yellow-green fluorescence by the wavelength conversion element 17, whereas the light F1 output from the light source LS2 The output light F2 is not subjected to wavelength conversion, and remains as the two types of light output from the light emitting elements 31 and 41 .

That is, in the illumination device 1B shown in FIG. 3 as well, the spectra of the two light sources LS1 and LS2 to be synthesized can be made different, so that a high color rendering illumination device can be realized like the illumination device 1A in FIG.

Furthermore, in the illumination device 1B of FIG. 3, one light source LS2 of the two light sources includes a plurality of (two in the example of FIG. 3) light emitting elements 31 and 41. As shown in FIG. Thereby, the spectra of the light output from these two light emitting elements 31 and 41 can also be made different. That is, the illumination device 1B shown in FIG. 3 can synthesize light from the three types of light sources LD1, LD2, and LD3 with different spectra. As a result, the types of light to be synthesized can be increased compared to the configurations of FIGS. 1 and 2, and the high color rendering properties of the illumination device can be further improved.

Note that in the illumination device 1B shown in FIG. 3, the structures of the two light sources LS1 and LS2 may be interchanged. 3, the light source LS1 may include the two solid-state light sources LD2 and LD3 without the wavelength conversion element 17, and the light source LS2 may include the excitation light source LD1 and the wavelength conversion element 17. good.

Also, both of the two light sources LS1 and LS2 may be configured to include a plurality of solid-state light sources LD2 and LD3 (light emitting elements 31 and 41).

As shown in FIGS. 2 and 3, only one of the two light sources LS1 and LS2 (the light source LS1 in the examples of FIGS. 2 and 3) connects the excitation light source LD1 (the light emitting element 11) and the wavelength conversion element 17. Even with such a configuration, it is possible to realize the illumination device 1 with high brightness, as in the example of FIG. 1 .

In the illumination device 1B of FIG. 3, blue can be set for the excitation light source LD1, red can be set for the solid-state light source LD2, and green can be set for the solid-state light source LD3 as a configuration for achieving high color rendering. Note that the colors of the solid-state light sources LD2 and LD3 may be reversed. In this case, light source LS1 emits yellow or yellow-green fluorescent light and blue light, and light source LS2 emits red and green light which, after entering combining optics 2, are guided to light homogenizing element 3, To realize a lighting device with high color rendering.

If it is desired to realize an inexpensive and high-brightness light source, the configuration of the lighting device 1A in FIG. do it. For example, the light emitting element 11 of the light source LS1 can use an efficient light source of around 455 nm as a phosphor excitation light source, and the light emitting element 21 of the light source LS2 can use a bright blue light source of around 465 nm. Note that the configurations of the light emitting element 11 of the light source LS1 and the light emitting element 21 of the light source LS2 may be reversed.

Also, if it is desired to realize a light source that is inexpensive and has high color reproducibility, the configuration of the lighting device 1A in FIG. . For example, the light emitting element 11 of the light source LS1 can use an efficient light source of around 455 nm as a phosphor excitation light source, and the light emitting element 21 of the light source LS2 can use a red light source of around 640 nm. Note that the configurations of the light emitting element 11 of the light source LS1 and the light emitting element 21 of the light source LS2 may be reversed.

Similarly, when it is desired to realize a light source that is inexpensive and has high color reproducibility, the configuration of the lighting device 1B in FIG. should be set to red. The excitation light source LD1 uses an efficient light source of around 455 nm as a phosphor excitation light source, the solid-state light source LD2 uses a bright blue light source of around 465 nm, and the solid-state light source LD3 uses a red light source of around 640 nm. can do. For example, the configurations of the light source LS1 and the light source LS2 may be reversed.

FIG. 4 is a schematic diagram showing a schematic configuration of a projector 50 to which the illumination device according to the embodiment is applied. The projector 50 includes an illumination optical system 51 and a projection lens 52 on the downstream side of the illumination device 1 shown in FIG. 1 in the light irradiation direction.

Light rays L are incident on the illumination optical system 51 from the light homogenizing element 3 (light tunnel) of the illumination device 1 and output to the projection lens 52 . The illumination optical system 51 has various elements such as a color wheel 53 and an optical modulator 54 inside. The color wheel 53 is a disk integrating red, blue, and green filters, and time-divides the incident light L into red, green, and blue by allowing the incident light L from the illumination device 1 to pass therethrough while rotating. converted into light. The optical modulator 54 is composed of a liquid crystal, a DMD (Digital Micromirror Device), or the like, and spatially modulates light rays passing through the color wheel 53 .

4 (and FIG. 5, which will be described later), the color wheel 53 and the light modulator 54 are shown inside the illumination optical system 51. However, these elements must be built in the illumination optical system 51. , and the arrangement of these elements is not limited to the examples in FIGS.

The projection lens 52 outputs the light beam modulated by the light modulator 54 of the illumination optical system 51 as a projection image P. In FIG. 4 , the direction (Y direction) in which the projection image P is output from the projection lens 52 is orthogonal to the optical axis direction (X direction) of the light L output from the illumination device 1 . In other words, the illumination device 1 is arranged such that the optical axis direction of the output light L of the illumination device 1 is orthogonal to the arrangement direction (Y direction) of the illumination optical system 51 and the projection lens 52 . In this case, the output light L of the illumination device 1 is directly input to the illumination optical system 51 .

In this embodiment, as described with reference to FIGS. (and the emission direction of the light L from the light homogenizing element 3 shown in FIG. 4). The two light sources LS1 and LS2 are arranged so that the optical axes of the light beams F1 and F2 output from the two light sources form an angle of 90 degrees.

With this configuration, when the illumination device 1 is applied to the projector 50 in the arrangement shown in FIG. It becomes possible to physically separate the heat-generating part and arrange it. This makes it possible to prevent heat sources from concentrating inside the projector 50, which is advantageous in thermal design.

On the other hand, a configuration in which two light sources are separated by 180 degrees as in the conventional method disclosed in Patent Document 2 is considered as a comparative example. If the illumination device of the comparative example is applied to a projector in the same manner as the arrangement shown in FIG. Therefore, concentration of heat sources may occur within the projector 50 .

Although the example of FIG. 4 exemplifies the configuration to which the lighting device 1 shown in FIG. 1 is applied, the configuration to which the lighting device 1A of FIG. 2 or the lighting device 1B of FIG. 3 is applied may be used.

FIG. 5 is a schematic diagram showing a modification 50A of the arrangement of the projectors. As shown in FIG. 5, the direction in which the projected image P is output from the projection lens 52 may be the same as the optical axis direction (X direction) of the light L output from the illumination device 1 . In other words, the illumination device 1 is arranged so that the optical axis direction of the output light L of the illumination device 1 is the same as the arrangement direction (X direction) of the illumination optical system 51 and the projection lens 52 . In this case, the output light L of the illumination device 1 is input to the illumination optical system 51 after its direction is changed using a reflective optical element 55 such as a mirror.

When the illumination device 1 is applied to the projector 50 with the arrangement shown in FIG. can be physically further apart than the arrangement illustrated in FIG. This makes it possible to further prevent heat sources from concentrating inside the projector 50, which is more advantageous in terms of thermal design.

The arrangement of the illumination device, projection lens, and illumination optical system in the projector is not limited to the examples shown in FIGS.

In this way, by applying the illumination devices 1, 1A, and 1B illustrated in FIGS. 1 to 3 to the projectors 50 and 50A, the projector 50 can be made smaller and more efficient in the same way as the illumination devices.

FIG. 6 is a diagram showing a first modified example 1C of the lighting device. The outline of FIG. 6 is similar to that of FIG. 6 and subsequent drawings, the Z-axis is provided in the direction orthogonal to both the X-axis and the Y-axis, that is, the depth direction of the paper surface of FIG. 6, and the direction along the Z-axis is the Z direction.

As shown in FIG. 6, a configuration in which a color wheel 53 is arranged in the illumination device 1C may be used. In the example of FIG. 6 , the color wheel 53 is arranged between the combining optical element 2 and the light homogenizing element 3 such that the light emitted from the combining optical element 2 after passing through the rotating color wheel 53 is , is incident on the light homogenizing element 3 .

In this embodiment, unlike Patent Documents 1 and 2 in which the synthesizing optical element 2 and the light homogenizing element 3 are integrated, the synthesizing optical element 2 and the light homogenizing element 3 are separate bodies. It is also possible to dispose a color wheel 53 between the synthesizing optical element 2 and the light homogenizing element 3, as in the illumination device 1C of the first modified example shown in FIG. As a result, the light can be processed by the color wheel 53 at a stage before it is input to the light uniformizing element 3, so that unevenness generated by the color wheel 53 can also be uniformed by the light uniformizing element 3. It becomes possible. As a result, the unevenness of the projection image P of the projector 50 can be further reduced.

6 illustrates the configuration of the illumination device 1 of FIG. 1, but in the configurations of the illumination devices 1A and 1B of FIGS. A configuration in which the wheel 53 is arranged may be used.

FIG. 7 is a schematic diagram showing an example of arrangement of the light homogenizing element 3 and the color wheel 53 in the illumination device 1C shown in FIG. FIG. 7 is a diagram of the illumination device 1C viewed from the X negative direction side. Also, in FIG. 7, a light tunnel is illustrated as the light homogenizing element 3 . Also, in this example, the Y direction is the horizontal direction, and a horizontal axis H parallel to the Y direction is defined. Similarly, a direction perpendicular to the X direction and the Y direction (vertical direction on the paper surface) is defined as a vertical direction, and a vertical axis V parallel to this vertical direction is defined.

As shown in FIG. 7, the light tunnel 3 has a substantially rectangular outer shape when viewed in the X direction. The horizontal axis H and vertical axis V mentioned above are set to intersect at the center C1 of this rectangular shape of the light tunnel 3 . The horizontal axis H of the light tunnel 3 is a plane parallel to the plane (XY plane) formed by the optical axes of the two incident light sources LS1 and LS2, and the vertical axis V of the light tunnel 3 is the horizontal axis H It is a plane that intersects perpendicularly with Also, the color wheel 53 is installed rotatably around a rotation axis parallel to the X direction, and the position of this rotation axis is shown as a center position C2 in FIG.

The definitions of the horizontal axis H and vertical axis V above can also be expressed as follows. The first and second directions, which are the optical axis directions of the two light beams F1 and F2 output from the two light sources LS1 and LS2, and the third direction, which is the optical axis direction of the light beam L passing through the light tunnel 3, are the same. are placed on the plane of In the examples of FIGS. 6 and 7, this plane is the XY plane, the first direction is the Y direction, and the second and third directions are the X direction. Then, in an orthogonal plane orthogonal to the third direction (that is, the same plane as the paper surface of FIG. 7), a horizontal axis H along the line of intersection with the XY plane, and an orthogonal plane orthogonal to the horizontal axis H and a vertical axis V. The horizontal axis H and the vertical axis V are determined to intersect at the center position C1 (first center) of the cross-sectional shape of the light tunnel 3 on the orthogonal plane.

Here, with the center C1 of the light tunnel 3 as the coordinate center, the angle between the vertical axis V and the straight line L1 connecting the center C1 and the center position C2 of the color wheel 53 is θ1. Further, with the center C1 of the light tunnel 3 as the coordinate center, the angle between the vertical axis V and the straight line L2 extending in the longitudinal direction from the center C1 of the light tunnel 3 is θ2. At this time, by arranging the light tunnel 3 and the color wheel 53 so that 0≦θ2≦θ1 is established, the light utilization efficiency of the color wheel 53 can be improved.

FIG. 8 is a diagram showing a second modification 1D of the lighting device. The outline of FIG. 8 is similar to that of FIG. As shown in FIG. 8, the two light sources LS1, LS2 may be configured with at least one optical profile adjustment element 19. FIG. In the example of FIG. 8, an optical profile adjusting element 19 is arranged between the optical element 14 and the reflective optical element 15 in each of the light sources LS1 and LS2. With this configuration, a highly efficient lighting device can be realized.

Note that one of the two light sources LS1 and LS2 may be configured to include the optical profile adjustment element 19 . Further, the position of the optical profile adjustment element 19 is not limited to the example shown in FIG. 8, and may be arranged at other positions on the optical paths within the light sources LS1 and LS2. Also, a plurality of optical profile adjustment elements 19 may be provided in each of the light sources LS1 and LS2. Further, similarly to the example of FIG. 4 , the illumination device 1D may have a configuration in which the color wheel 53 is provided inside the illumination optical system 51 .

9 and 10 are diagrams showing a third modification 1E of the lighting device. FIG. 9 shows the configuration of the XY plane view of the illumination device 1E viewed from the positive Z direction side. FIG. 10 is a view of the illumination device 1E shown in FIG. 9 as viewed from the X negative direction side. The configuration of the lighting device 1E shown in FIG. 9 as viewed from the XY plane is the same as that of the lighting device 1D shown in FIG.

As shown in FIG. 10, in the light source LS1, the plane formed by the optical axis from the light emitting element 11 to the wavelength conversion element 17 is defined as "plane A". Here, as shown in FIGS. 9 and 10, the plane A is defined by both the substantially central axis (optical axis A1) of the optical element 13 and the optical axis A2 obtained by bending the optical axis A1 by the reflective optical element 15. corresponds to the containing plane. The light beam F1 entering the light homogenizing element 3 from the light source LS1 described above is also arranged along the plane A. As shown in FIG. Also, as shown in FIG. 10, the plane A is parallel to the XY plane.

Similarly, as shown in FIG. 10, in the light source LS2, the plane formed by the optical axis from the light emitting element 11 to the wavelength conversion element 17 is defined as "plane B". Here, as shown in FIGS. 9 and 10, the plane B is defined by both the substantially central axis (optical axis B1) of the optical element 13 and the optical axis B2 obtained by bending the optical axis B1 by the reflective optical element 15. corresponds to the containing plane. The light beam F2 entering the light homogenizing element 3 from the light source LS2 mentioned above is also arranged along the plane B. FIG. Also, as shown in FIG. 10, the plane B is parallel to the XY plane.

Further, as shown in FIG. 10, the illumination device 1E of the third modification is characterized in that these planes A and B do not intersect. In other words, the light source LS1 and the light source LS2 are installed so that the plane A and the plane B are arranged in parallel so that they are equidistant in the Z direction. This allows efficient coupling in the longitudinal direction of the light homogenizing element 3 .

FIG. 11 is an example of a condensed spot at the entrance of the light homogenizing element 3 in the third modification. In FIG. 11 an example of the profile P1, P2 of the focused spots of the two light source modules LS1, LS2 at the entrance of the light homogenizing element 3 is illustrated. In the light source LS1 on the reflection side, which is reflected by the synthesizing optical element 2 and inputs the reflected light to the light uniformizing element 3, the condensing position is relatively close to the synthesizing optical element 2. FIG. On the other hand, in the light source LS2 on the straight-ahead side, the light is input to the light homogenizing element 3 without being reflected by the synthesizing optical element 2, and the condensing position is relatively close to the entrance of the light homogenizing element 3. FIG. For this reason, the two light sources LS1, LS2 are characterized by different profiles P1, P2 of the focused spots at the entrance of the light homogenizing element 3 . In other words, the two light sources LS 1 , LS 2 are installed such that there is a difference in the profile P 1 , P 2 of the focused spots at the entrance of the light homogenizing element 3 . As shown in FIG. 11, the profile P1 of the focused spot of the light source LS1 reflected by the reflecting surface 2A of the synthesizing optical element 2 is relatively large, and the light source LS2 that does not pass through the reflecting surface 2A of the synthesizing optical element 2 is relatively large. is relatively small. This can minimize loss during synthesis.

In addition, two light source modules LS1, It is characterized in that the vertical and horizontal directions of the profiles P1 and P2 of the condensed spot of LS2 are inclined. In the example of FIG. 11, the shape of the entrance of the light homogenizing element 3 is substantially rectangular when viewed in the X direction, similar to the example shown in FIG. It is arranged so that it is slanted. Further, as described with reference to FIG. 10, in the illumination device 1E of the third modification, the plane A including the optical axes A1 and A2 of the light source LS1 and the plane B including the optical axes B1 and B2 of the light source LS2 are It is parallel to the XY plane. Therefore, in the example of FIG. 11 , the vertical and horizontal directions of the profiles P1 and P2 of the focused spots of the two light source modules LS1 and LS2 can be tilted with respect to the vertical and horizontal directions of the light uniformizing element 3 .

Furthermore, as shown in FIG. 11, the central positions of the profiles P1 and P2 of the condensed spots of the two light source modules LS1 and LS2, respectively, are within the range of the entrance of the light homogenizing element 3 in the horizontal direction ( In the example, they are shifted in the Y direction). The horizontal direction can also be expressed as a direction parallel to the direction of the light beam F1 incident on the reflecting surface 2A. By adopting such a configuration, internal reflection within the light uniformizing element 3 is increased to some extent, which contributes to uniformity, and illumination uniformity within the projection screen (projection image P) can be further enhanced. .

FIG. 12 is a diagram showing the relationship between the synthesizing optical element 2 and the light homogenizing element 3 and the planes A and B of the two light sources LS1 and LS2 in the third modification. In FIG. 12, only the related elements of the illumination device 1E of the third modification are illustrated as viewed from the Y negative direction side.

The synthesizing optical element 2 is an optical element having one or more reflecting surfaces 2A, and is configured in the shape of a triangular prism in FIG. FIG. 12 shows a light synthesizing unit of the illumination device 1E that synthesizes the illumination light from the two light source modules LS1 and LS2 into one illumination light. In the light synthesizing portion, when the synthesizing optical element 2 determines the central axis C1 (see also FIG. 7) of the light homogenizing element 3 as shown in FIG. 12, the plane defined in FIG. A and plane B are located.

When the synthesizing optical element 2 is arranged in this way, the synthesizing optical element 2 reflects one of the two light beams F1 input from two directions. On the other hand, the other of the two light beams F2 is passed through the combining optical element 2 at a position on the Z positive direction side of the side surface 2D on the Z positive direction side of the combining optical element 2, without passing through the combining optical element 2, and together with the reflected light F1. , are incident on the light homogenizing element 3 and combined. Here, the synthesizing optical element 2 is configured separately from the light homogenizing element 3 . With this configuration, it is possible to reduce the loss of synthetic light in the rectilinear direction.

Further, in the configuration of the third modified example shown in FIG. , and the shape of the combining optical element 2 can be simplified. In addition, since the synthesizing optical element 2 is configured separately from the light homogenizing element 3, it is possible to insert the color wheel 53 between the synthesizing optical element 2 and the light homogenizing element 3, thereby reducing the amount of light. Unevenness can be reduced.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each specific example described above and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. As long as there is no technical contradiction, the combination of the elements included in the specific examples described above can be changed as appropriate.

Aspects of the present invention are, for example, as follows.
<1> Two light sources,
a synthesizing optical element for synthesizing the two light beams output from the two light sources;
a light homogenizing element;
with
The synthesizing optical element reflects one of the two light beams input from two directions and transmits the other light, and causes the reflected light and the transmitted light converted in the same direction to enter the light homogenizing element. synthesize,
The synthesizing optical element is composed of a prism having four or more multifaceted surfaces, one of the multifaceted surfaces is a reflecting surface that generates the reflected light, and two opposing surfaces generate the transmitted light. is a transparent surface,
The synthesizing optical element is configured separately from the light homogenizing element,
configured so that the light rays incident on the reflecting surface and the transmitting surface of the synthesizing optical element do not overlap on the synthesizing optical element;
lighting device.
<2> The light homogenizing element is composed of a rod integrator,
The illumination device according to <1>.
<3> The light homogenizing element is configured by a light tunnel,
The illumination device according to <1>.
<4> one of the two light sources is arranged at a position where the optical axis is 90 degrees with respect to the incident direction to the light uniformizing element;
The two light sources are arranged so that the angle formed by the optical axes of the two is 90 degrees,
The lighting device according to any one of <1> to <3>.
<5> At least one of the two light sources includes an excitation light source and a wavelength conversion element.
The lighting device according to any one of <1> to <4>.
<6> At least one of the two light sources includes a plurality of optical elements.
The lighting device according to any one of <1> to <5>.
<7> the two light beams synthesized by the synthesizing optical element have different spectra;
The lighting device according to any one of <1> to <6>.
<8> At least one of the entrance surface and the exit surface of the prism is a diffusion surface,
The lighting device according to any one of <1> to <7>.
<9> A color wheel is arranged between the synthesizing optical element and the light homogenizing element.
The lighting device according to any one of <1> to <8>.
<10> The first and second directions, which are the optical axis directions of the two light beams output from the two light sources, and the third direction, which is the optical axis direction of the light beams passing through the light uniformizing element, are the same. arranged to be on a plane,
In an orthogonal plane orthogonal to the third direction, define a horizontal axis along a line of intersection with the plane and a vertical axis orthogonal to the horizontal axis and along the orthogonal plane, wherein the horizontal axis and the when the vertical axis is defined to intersect at a first center, which is the center position of the cross-sectional shape of the light homogenizing element on the orthogonal plane,
With the first center as the coordinate center, the angle between the vertical axis and a straight line connecting the first center and the center position C2 of the color wheel is θ1, and the vertical axis and the light uniformity from the first center When the angle formed by the straight line extending in the longitudinal direction of the cross-sectional shape along the orthogonal plane of the conversion element is θ2,
wherein the light homogenizing element and the color wheel are arranged such that 0≦θ2≦θ1 holds;
The illumination device according to <9>.
<11> At least one of the two light sources includes at least one optical profile adjustment element.
The lighting device according to any one of <1> to <10>.
<12> The two light sources include an optical element and a wavelength conversion element,
In one of the two light sources, a plane formed by an optical axis from the light emitting element to the wavelength conversion element is defined as a "plane A";
In the other of the two light sources, when the plane formed by the optical axis from the light emitting element to the wavelength conversion element is defined as "plane B",
The two light sources are installed so that the plane A and the plane B do not intersect.
The lighting device according to any one of <1> to <11>.
<13> The two light sources are installed such that there is a difference in the profile of the focused spots at the entrance of the light homogenizing element.
The lighting device according to any one of <1> to <12>.
<14> the entrance of the light homogenizing element has a substantially rectangular shape;
such that the longitudinal and lateral directions of the profile of the focused spots of the two light sources at the entrance of the light homogenizing element are tilted with respect to the longitudinal and lateral directions of the shape of the light homogenizing element, and
the two light sources are positioned such that the central positions of the profiles are staggered in a direction parallel to the direction of light rays incident on the reflective surface within the range of the entrance of the light homogenizing element;
The lighting device according to any one of <1> to <13>.
<15> two light sources;
a synthesizing optical element for synthesizing the two light beams output from the two light sources;
a light homogenizing element;
with
The synthesizing optical element reflects one of the two light beams input from two directions and allows the other to pass through without passing through the synthesizing optical element, so that the reflected light converted in the same direction and the light incident on the homogenizing element and combined,
The synthesizing optical element is configured separately from the light homogenizing element,
lighting device.
<16>
the lighting device according to any one of <1> to <15>;
a projection lens;
projector.

Reference Signs List 1, 1A, 1B, 1C, 1D, 1E lighting device 2 combining optical element 2A reflecting surface 2B, 2C transmitting surface 3 light homogenizing element 11 light emitting element (excitation light source)
17 wavelength conversion element 19 light profile adjustment element 50 projector 52 projection lens 53 color wheel LS1, LS2 light source LD1 excitation light source F1, F2 light beam H horizontal axis V vertical axis C1 center position of light homogenizing element C2 center position of color wheel L1 vertical an axis, a straight line L2 connecting the center position of the light homogenizing element and the center position of the color wheel; Straight line θ1 Angle formed between vertical axis V and straight line L1 θ2 Angle formed between vertical axis V and straight line L2 A, B Planes P1, P2 Condensed spots of two light source modules LS1, LS2 at the entrance of the light homogenizing element profile

JP-A-2000-075407 Japanese Patent No. 6283932

Claims (16)

two light sources;
a synthesizing optical element for synthesizing the two light beams output from the two light sources;
a light homogenizing element;
with
The synthesizing optical element reflects one of the two light beams input from two directions and transmits the other light, and causes the reflected light and the transmitted light converted in the same direction to enter the light homogenizing element. synthesize,
The synthesizing optical element is composed of a prism having four or more multifaceted surfaces, one of the multifaceted surfaces is a reflecting surface that generates the reflected light, and two opposing surfaces generate the transmitted light. is a transparent surface,
The synthesizing optical element is configured separately from the light homogenizing element,
configured so that the light rays incident on the reflecting surface and the transmitting surface of the synthesizing optical element do not overlap on the synthesizing optical element;
lighting device. the light homogenizing element is constituted by a rod integrator;
The lighting device according to claim 1 . the light homogenizing element is constituted by a light tunnel;
The lighting device according to claim 1 . one of the two light sources is arranged at a position where the optical axis is 90 degrees with respect to the direction of incidence on the light uniformizing element;
The two light sources are arranged so that the angle formed by the optical axes of the two is 90 degrees,
The lighting device according to claim 1 . at least one of the two light sources comprises an excitation light source and a wavelength conversion element;
The lighting device according to claim 1 . at least one of the two light sources comprises a plurality of optical elements;
The lighting device according to claim 1 . The two light beams synthesized by the synthesizing optical element have different spectra,
The lighting device according to claim 1 . At least one of the entrance surface and the exit surface of the prism is a diffusion surface,
The lighting device according to claim 1 . a color wheel is positioned between the combining optics and the light homogenizing element;
The lighting device according to claim 1 . The first and second directions, which are optical axis directions of the two light beams output from the two light sources, and the third direction, which is the optical axis direction of the light beams passing through the light uniformizing element, are on the same plane. placed above,
In an orthogonal plane orthogonal to the third direction, define a horizontal axis along a line of intersection with the plane and a vertical axis orthogonal to the horizontal axis and along the orthogonal plane, wherein the horizontal axis and the when the vertical axis is defined to intersect at a first center, which is the center position of the cross-sectional shape of the light homogenizing element on the orthogonal plane,
With the first center as the coordinate center, the angle between the vertical axis and a straight line connecting the first center and the center position C2 of the color wheel is θ1, and the vertical axis and the light uniformity from the first center When the angle formed by the straight line extending in the longitudinal direction of the cross-sectional shape along the orthogonal plane of the conversion element is θ2,
wherein the light homogenizing element and the color wheel are arranged such that 0≦θ2≦θ1 holds;
10. A lighting device according to claim 9. at least one of the two light sources comprises at least one light profile adjusting element;
The lighting device according to claim 1 . The two light sources comprise a light emitting element and a wavelength conversion element,
In one of the two light sources, a plane formed by an optical axis from the light emitting element to the wavelength conversion element is defined as a "plane A";
In the other of the two light sources, when the plane formed by the optical axis from the light emitting element to the wavelength conversion element is defined as "plane B",
The two light sources are installed so that the plane A and the plane B do not intersect.
The lighting device according to claim 1 . The two light sources are positioned such that there is a difference in the profile of the focused spots at the entrance of the light homogenizing element.
The lighting device according to claim 1 . the entrance of the light homogenizing element has a substantially rectangular shape,
such that the profile of the focused spots of the two light sources at the entrance of the light homogenizing element is tilted longitudinally and laterally with respect to the longitudinal and lateral directions of the shape of the light homogenizing element, and
the two light sources are positioned such that the central positions of the profiles are staggered in a direction parallel to the direction of light rays incident on the reflective surface within the range of the entrance of the light homogenizing element;
The lighting device according to claim 1 . two light sources;
a synthesizing optical element for synthesizing the two light beams output from the two light sources;
a light homogenizing element;
with
The synthesizing optical element reflects one of the two light beams input from two directions, and allows the other to pass through without passing through the synthesizing optical element, so that the reflected light converted in the same direction and the light incident on the homogenizing element and combined,
The synthesizing optical element is configured separately from the light homogenizing element,
lighting device. A lighting device according to any one of claims 1 to 15;
a projection lens;
projector.

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