JP6790170B2 - Light source optical system and projection type display device using this - Google Patents

Description

The present invention relates to a light source optical system and a projection type display device using the same.

In recent years, a projector has been developed in which a phosphor is irradiated with a light beam emitted from a high-power laser diode (hereinafter, LD) as excitation light and the wavelength-converted fluorescent light is used as a light source. In such a projector, it is possible to increase the brightness of the projector by increasing the number of LDs or increasing the output.

However, if the intensity of the incident light on the phosphor is increased in order to increase the brightness, the light density of the light source spot formed on the phosphor surface is increased. As a result, there is a problem that the light conversion efficiency is lowered due to the brightness saturation phenomenon, and it is not possible to obtain the brightness proportional to the increase in the output of the LD.

The technique described in Patent Document 1 is known as a technique for solving such a problem. Patent Document 1 discloses a configuration in which two fly-eye lenses are provided after an optical system that compresses light fluxes from a plurality of LDs. With such a configuration, it is possible to make the light density of the light source spot formed on the phosphor uniform, suppress the formation of a region where the light density becomes extremely high, and suppress the above-mentioned decrease in the light conversion efficiency. it can.

Japanese Unexamined Patent Publication No. 2012-118110

In recent years, further suppression of a decrease in the light conversion efficiency of a phosphor has been required.

Therefore, an object of the present invention is to provide a light source optical system capable of suppressing a decrease in light conversion efficiency of a wavelength conversion element and a projection type display device using the same.

A light source optical system that guides the luminous flux from a light source to a wavelength conversion element.
A first lens plane array with a plurality of first lens planes,
A second lens surface array having a plurality of second lens surfaces and receiving a light flux from the first lens surface array,
A condensing optical system that guides the luminous flux from the second lens surface array to the wavelength conversion element and has positive power,
A light guide surface for guiding a light flux from the second lens surface array to the wavelength conversion element via the condensing optical system is provided.
The luminous flux diameter of the light flux from the second lens surface array is smaller than the luminous flux diameter of the light flux guided from the condensing optical system to the light guide surface.
F-number F _LD of the light converging optical system divided by the beam diameter of the light beam guided to the focal length to the light guide surface from said second lens surface array excitation light path of, is formed on the wavelength converting element When the length of one side of the light source spot is _dphos ,

It is characterized by satisfying.

According to the present invention, it is possible to provide a light source optical system capable of suppressing a decrease in light conversion efficiency of a wavelength conversion element and a projection type display device using the same.

Configuration explanatory view of the light source apparatus shown in the 1st Example of this invention Configuration explanatory view of the dichroic mirror The figure which shows the homogenization of the laser luminous flux by a lens array Diagram showing the definition of luminous flux diameter Explanatory drawing of relationship between lens array and light source image used in 1st Example of this invention The figure which shows the change of the angle variation by passing through an afocal system The figure which shows the relationship between the F number of the excitation optical path and the fluorescence optical path. Configuration explanatory view of the light source apparatus shown in the 2nd Example of this invention Configuration explanatory view of a projector which can mount the light source device shown in each Example of this invention

Preferred embodiments of the present invention will be exemplified below with reference to the drawings. However, the relative arrangement of the components described in this embodiment should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. That is, the present invention is not limited to the embodiments described later, and various modifications and changes can be made within the scope of the gist thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Example]
(Structure of light source optical system and light source device)
FIG. 1 is a configuration diagram showing a configuration of a light source device as a first embodiment of the present invention. In FIG. 1, the direction parallel to the optical axis of the condensing lens unit 8 described later is the X-axis direction, and the direction in which the X-axis direction and the plane parallel to the normal of the dichroic mirror 7 described later are the XZ cross section is the Z axis. The direction is defined as the direction orthogonal to the X-axis direction and the Z-axis direction as the Y-axis direction. That is, FIG. 1 is a cross-sectional view of the XZ as shown in the coordinate axes shown in the drawing.

The light source device shown in this embodiment includes a light source 1, a collimator lens 2, a phosphor 9, and a light source optical system. The light source optical system referred to here refers to a microlens array 63, a dichroic mirror 7 (light guide element), a condenser lens unit 8 (condensing optical system), and a light guide optical system. The light guide optical system refers to a parabolic mirror array 3 composed of a plurality of mirrors each having a different radius of curvature and apex coordinates, a flat mirror 4, and a concave lens 5.

(Optical path from light source 1 to illumination optical system)
The light source 1 is an LD that emits blue light. The luminous flux emitted from the light source 1 is a divergent luminous flux, and the same number of collimator lenses 2 as the light source 1 are provided in the traveling direction of the luminous flux from the light source 1. The collimator lens 2 is a positive lens that converts the radiated luminous flux from the light source 1 into a parallel luminous flux.

After ejecting the collimator lens 2, the plurality of luminous fluxes travel in the Z-axis direction and then head toward the plane mirror 4 while shortening the distance between them by the parabolic mirror array 3. The luminous flux reflected by the plane mirror 4 is incident on the concave lens 5. Since the concave lens 5 shares the focal position with the focal point of the radial mirror array 3, the concave lens 5 emits a light flux as a parallel light flux.

The parallel light flux ejected from the concave lens 5 is incident on the first lens surface array 61, which is the surface on the concave lens 5 side of the surface of the microlens array 63, and is divided into a plurality of light beams into the second lens surface array 62. Incident. That is, the second lens surface array 62 is provided at a position where the light flux from the first lens surface array 61 is received.

The divided light beam emitted from the second lens surface array 62 is reflected by the dichroic mirror 7 and heads toward the condenser lens unit 8. The dichroic mirror 7 has a minimum size necessary to reflect the light beam from the second lens surface array 62, and the blue light from the light source 1 is reflected on the surface thereof, but the wavelength of the fluorescent light described later is A dielectric multilayer film (dichroic film) with permeable properties is coated.

(Structure of dichroic mirror 7)
The detailed configuration of the dichroic mirror 7 is as shown in FIG. The dichroic mirror 7 shown in FIG. 1 has the configuration shown in FIG. 2 (a). Specifically, light is transmitted to the left and right in the y-axis direction of the dichroic surface 71, which is a light guide surface that reflects blue light from the light source 1 and transmits fluorescent light including green light and red light, regardless of wavelength. It has a structure in which a transparent surface 72 is provided.

The dichroic mirror 7 is not limited to the configuration shown in FIG. 2A, and even if the dichroic mirror 7 is provided with a transmission surface 72 around the dichroic surface 71, for example, as shown in FIG. 2B. Good. Further, at least one side of the dichroic surface 71 may overlap with one side having the transmission surface 72, and the transmission surface 72 may be a surface on a transparent substrate or a surface provided with an antireflection coating. There may be.

If the normal of the dichroic surface 71 is parallel to the normal of the dichroic surface 71 and is not included in the cross section including the optical axis of the condenser lens unit 8, the surface obtained by vertically projecting the dichroic surface 71 onto this cross section will be described later. The width D _d of may be defined.

The divided light flux reflected by the dichroic mirror 7 is focused and superimposed on the phosphor 9 by the condenser lens unit 8 having a positive power. As a result, a light source spot is formed on the phosphor 9. Since the light source spots formed on the phosphor 9 are conjugate to each lens cell (lens surface) of the first lens surface array 61, they have a rectangular and uniform distribution.

(Structure that suppresses the decrease in the light conversion efficiency of the phosphor 9)
Here, the reason why the decrease in the light conversion efficiency of the phosphor 9 can be suppressed by providing the microlens array 63 with reference to FIG. 3 will be described.

FIG. 3 is a simplified view showing the optical relationship between the first lens surface array 61, the second lens surface array 62, the condenser lens unit 8, and the phosphor 9 shown in FIG. The first lens surface array 61 corresponds to 61', the second lens surface array 62 corresponds to 62', the condenser lens unit 8 corresponds to 8', and the phosphor 9 corresponds to 9', respectively.

The phosphor 9'is arranged at a position substantially conjugate with each lens cell of the first lens array 61'by the second lens surface array 62'and the condensing lens unit 8', and the first lens surface array 61' 'And the 9'plane of the phosphor are in an imaging relationship. Therefore, a light source image corresponding to the light distribution formed on each lens cell of the first lens surface array 61'is formed on the phosphor 9'. The size of the image is determined by the pitch of the lens cell (width of the lens cell) and the magnification of the imaging system. Further, the light source images formed on each lens cell are arranged so as to be superimposed on the phosphor 9'via the condenser lens unit 8'.

As shown on the left side of FIG. 3, even if the luminous flux incident on the first lens surface array 61'has a non-uniform luminance distribution, the light distribution formed on each lens cell is limited to the number of lens cells for the above reason. To be averaged. Therefore, as shown on the right side of FIG. 3, a light source image having a uniform distribution can be formed on the 9'plane of the phosphor.

Returning to FIG. 1, when the luminous flux collimated by the concave lens 5 is incident on the first lens surface array 61, the luminous fluxes from the respective light sources 1 are arranged at intervals in the discrete light distribution. Is. However, by dividing and superimposing by the above path, a light source image having a uniform light distribution similar to the shape of each lens cell of the first lens surface array 61 is formed on the phosphor 9. Therefore, it is possible to suppress the concentration of the luminous flux from the light source 1 on the phosphor 9 to one point, and to suppress the decrease in luminous efficiency due to the luminance saturation phenomenon.

(Configuration to achieve miniaturization)
The blue light from the light source 1 incident on the phosphor 9 is converted into fluorescent light (converted light) mainly having spectra of red light and green light. The phosphor 9 is formed by coating a phosphor layer on a high-reflectance aluminum substrate, and the fluorescent light converted from blue light to fluorescence is reflected by the aluminum substrate toward the condenser lens unit 8. In addition, some blue light is reflected by the aluminum substrate with the same wavelength without being fluorescently converted.

In this way, a white light beam composed of fluorescent light including red light and green light and unconverted blue light is emitted from the phosphor 9, and is condensed and parallelized by the condenser lens unit 8 to form an illumination optical system (not shown). Head.

At this time, consider the case where the width of the dichroic mirror 7, more specifically, the width of the dichroic surface 71 is sufficiently larger than the diameter of the white light flux from the condenser lens unit 8. In this case, of the white light flux passing through the dichroic surface 71, the blue light is reflected by the dichroic surface 71 and returns to the light source 1 side, and cannot go to the illumination optical system.

That is, the larger the width of the dichroic surface 71, the more the blue light is impaired. As a solution to such impairment of blue light, as described in Patent Document 1, a configuration in which a blue light source is provided in addition to the light source 1 that emits excitation light can be considered, but in this configuration, the entire device becomes large. .. Therefore, in this embodiment, in order to reduce the impaired blue light as much as possible, it is considered to make the area of the dichroic mirror 7 as small as possible.

Specifically, in this embodiment sets the width D _c of the width D _d and the condenser lens unit 8 dichroic surface 71 so as to satisfy the following condition. That is, the dichroic surface 71 is in a direction (Z-axis direction) parallel to the normal line of the dichroic mirror 7 and orthogonal to the optical axis of the condenser lens unit 8 in a cross section (XZ cross section) including the optical axis of the condenser lens unit 8. The width D _{d of} is narrower than the width D _c of the condenser lens unit 8.

In such a configuration, the blue light contained in the light flux passing through the dichroic surface 71 among the white light flux from the condenser lens unit 8 returns to the light source 1, but the light flux not passing through the dichroic mirror 7 remains as it is in the illumination optical system. Guided to. That is, it is possible to guide the white luminous flux to the illumination optical system without providing the blue light source and the optical system around it separately from the light source for the excitation light, and it is possible to realize a compact light source optical system.

When the dichroic mirror 7 has the configuration shown in FIG. 2A, the width of the dichroic mirror 7 in the Z-axis direction may be defined as D _d . On the other hand, as in the configuration shown in FIG. 2B, when the transmission surface 72 is present in the XZ cross section in addition to the dichroic surface 71, the width of the dichroic surface 71 in the Z-axis direction may be D _d .

(Definition of luminous flux diameter)
Making the width Dd narrower than the width Dc makes the luminous flux diameter D _LD of the excitation light emitted from the microlens array 63 smaller than the luminous flux diameter D _phos of the white light flux from the condenser lens unit 8 by using the luminous flux diameter. In other words, that. The definition of the luminous flux diameter referred to here will be described with reference to FIG.

FIG. 4A shows a luminance cross-sectional view of a light source image of excitation light formed on the second lens surface array 62. As described above, the light flux divided by the 61st surface of the first lens array is focused on the 62nd surface of the second lens array, and an image of the light emitting point of the LD is formed at the condensing point.

Therefore, the luminance cross-sectional view shown in FIG. 4A has a discrete distribution in which a number of luminance peaks corresponding to the lens cell pitch of the first lens surface array 61 are arranged. In this case, the luminous flux diameter D _LD of the excitation light from the microlens array 63 is set to be a half-value half width in the envelope E of the luminance cross section, that is, a width in which half the luminance of the maximum luminance I can be obtained.

On the other hand, FIG. 4B shows a luminance cross-sectional view of the light distribution of the white luminous flux from the condenser lens unit 8. While the fluorescent light from the phosphor 9 emits light in all directions, it also emits surface light from the surface of the phosphor 9, so that it can be regarded as a completely diffused surface light source. Therefore, the luminance cross section of the fluorescent light beam has the strongest luminance near the optical axis, and the luminance becomes weaker as the distance from the optical axis corresponds to the cosine of the fluorescence light capture angle by the condenser lens unit 8. The brightness is 0 at the limit point of the capture angle determined by the effective diameter of the lens. In this case, the luminous flux diameter of the fluorescent light, that is, the luminous flux diameter D _phos of the white luminous flux from the condenser lens unit 8 is the width of the position where the brightness becomes 0.

From the above, it is possible to suppress a decrease in the light conversion efficiency of the phosphor by the configuration of this example. Further, the miniaturization of the light source device can be achieved.

(Issues by reducing the luminous flux diameter of the excitation light)
Here, in order to suppress the impairment of blue light due to the large size of the dichroic mirror 7, it is considered to further reduce the area of the dichroic mirror 7. When the area of the dichroic mirror is further reduced, it is necessary to further reduce the luminous flux diameter of the excitation light emitted from the second lens surface array 62. However, if the luminous flux diameter of the excitation light is reduced, the following problems occur. Hereinafter, the problem will be described with reference to FIGS. 5 and 6.

FIG. 5 is an enlarged view of the first and second lens surface arrays 61 and 62 in this embodiment. As shown in FIG. 5A, the parallel light flux divided by the first lens surface array 61 is applied to each lens cell of the second lens surface array 62 corresponding to each lens cell of the first lens surface array 61. Condensing. As a result, a light source image of the light source 1 is formed in each lens cell of the second lens surface array 62.

If the size of this light source image is larger than the pitch of the lens cell, a part of the luminous flux is incident on the lens cell adjacent to the corresponding lens cell. Such a component is imaged on the phosphor 9 at a position adjacent to the position of a predetermined light source spot, and is effectively used because it is eclipsed by an optical element in the illumination optical system arranged in the subsequent stage. Light that is not done, that is, loss. As a result, the light utilization efficiency is reduced.

On the other hand, FIG. 5B shows a case where the luminous flux diameter of the excitation light is made smaller in order to reduce the area of the dichroic mirror 7 as described above. In FIG. 5B, the light source image formed in each lens cell of the second lens surface array 62 exceeds the size of the lens cell, and the lens cell adjacent to the corresponding lens cell as described above is formed. The incident light beam further reduces the light utilization efficiency. This is because by reducing the luminous flux diameter of the excitation light incident on the first lens surface array 61, the angular variation of the excitation light flux as a parallel luminous flux becomes large.

(Agular variation in luminous flux diameter of excitation light)
The principle will be described with reference to FIG. FIG. 6 is a simplified view showing the optical relationship of each optical element from the light source 1 to the concave lens 5. 1'is a light source 1, 2'and 3'is an element having a positive power, and corresponds to each mirror of the collimator lens 2 and the parabolic mirror array 3, respectively. 5'is an element having a negative power and indicates a concave lens 5.

As described above, the parabolic mirror array 3 and the concave lens 5 share the same focus, forming a so-called afocal system. Therefore, the elements 3'and 5'corresponding to both also form the afocal system A. The light emitted from the light source 1'is collimated by the collimator lens 2', is incident on the afocal system A, and the luminous flux is compressed at a predetermined magnification.

At this time, if the light emitting point of the light source 1'is infinitely small, it becomes completely parallel light by the collimated lens 2', but since the light emitting point of the LD has a finite size, the angle variation corresponding to the size. It becomes a parallel light source having θ ₁ . The angle variation θ ₁ is expressed by θ = atan (L / f _coli ) using the focal length f _coli of the collimator lens _2'and the size L of the light emitting point.

In this way, the parallel light flux incident on the afocal system A has an angle variation θ ₁ corresponding to the finite size of the light emitting point, but the angle when the parallel light is incident on the afocal system A and the luminous flux diameter changes. The variation changes to θ ₂ . Now, assuming that the diameters of the parallel luminous flux before and after the incident of the afocal system A are D ₁ and D ₂ , respectively, the following equation holds from the relationship of the angular magnification.

Here, γ is an angular magnification. Making the luminous flux diameter of the excitation light incident on the first lens surface array 61 smaller is equivalent to making the luminous flux diameter D ₂ emitted from the afocal system A smaller. When the luminous flux diameter D2 is reduced, the angular magnification γ is increased, and the numerical value of the term on the left side is increased accordingly, so that θ ₂ is increased.

Therefore, if the diameter of the light flux emitted from the afocal system is reduced, the angle variation θ _{2 becomes} large, and in the subsequent stage, the angle variation θ ₂ of the parallel light flux incident on the first lens surface array 61 also becomes large. Then, as shown in FIG. 5B, the size of the light source image on the second lens surface array 62 becomes large. That is, if the area of the dichroic mirror 7 is made small and the luminous flux diameter of the excitation light is made too small for the purpose of suppressing the deterioration of the blue light, the size of the light source image formed on the second lens surface array 62 becomes the lens cell. It is not preferable because it becomes larger than the pitch of and the light utilization efficiency is lowered.

Here, consider a case where the light source spot formed on the phosphor 9 is reduced. This means that the pitch of the lens cells of the first lens surface array 61 having an imaging relationship with the phosphor 9 is reduced. When the pitch of the lens cells of the second lens surface array 62 is also reduced in accordance with the reduction of the pitch of the lens cells of the first lens surface array 61, the size of the light source image is relative to the size of the lens cells. growing. As a result, the light utilization efficiency is lowered as described above, which is not preferable.

(More preferred form)
In order to adopt the configuration of this embodiment while suppressing such loss, it is desirable that the luminous flux diameter of the excitation optical path and the size of the light source spot on the phosphor 9 are the following conditions. Incidentally, in the description below and the values focal length of f _c divided by the beam diameter of the focusing lens unit 8 and F-number, although the beam diameter is described by substituting the F-number, because as follows is there.

Focal length of the condensing lens unit 8 in this embodiment is a f _{c =} 15 mm, the focal length of the condenser lens unit 8 may design freedom. Therefore, when the effective diameter of each optical element in the illumination optical system is large, the focal length may be proportionally multiplied to increase the luminous flux diameter of the fluorescent light while maintaining the capture angle. In this case, the luminous flux diameter of the excitation light changes in proportion to the focal length of the condenser lens, but the luminous flux diameter can be generalized by dividing each luminous flux diameter by the focal length of the condenser lens, so that the calculation is performed. convenient.

When the beam diameter of the white light beam from the condenser lens unit 8 in this embodiment and _D phos = 30 _mm, F-number in order to be f c = 15 mm, the

Is. On the other hand, when the luminous flux diameter of the excitation light from the microlens array 63 is D _LD = 15 mm, the F number becomes

Is.

That is, in this embodiment, as shown in FIG. 7A, the excitation light is collected in the phosphor 9 with respect to the F number of the fluorescent optical path, which is the optical path in which the fluorescent light is condensed by the condenser lens unit 8. The F number of the excitation optical path, which is the optical path to be illuminated, is large.

Suppose that the F number of the fluorescence optical path and the F number of the excitation optical path are almost equal. In this case, as shown in FIG. 7B, all or most of the unconverted light from the condenser lens unit 8 is reflected by the dichroic mirror 7 and is not guided to the illumination optical system, which is not preferable because the loss increases. Therefore, the relationship shown in FIG. 7A is preferable.

More preferably, the F-number of the fluorescent light path defined by the conditional expression (2) and F _phos, when the conditional expression (3) fluorescence light path F-number of which is defined by the F _LD, the light source optical system,

You should be satisfied.

Is to increase the F-number F _LD excitation optical path going beyond the lower limit of conditional expression (4), that means to reduce the beam diameter D _LD excitation light. When the beam diameter D _LD excitation light is too small, preferably to lower the light use efficiency size of the light source image formed as described above the second lens surface array 62 is larger than the pitch of the lens cells Absent.

On the other hand, as going beyond the upper limit of conditional expression (4) means that the F-number F _LD with F-number F _phos fluorescence light path excitation light path are close, in this case shown in FIG. 7 (b) It is not preferable because the loss increases.

Further, in this embodiment, a total of 4 units of 8 LDs are used as a light source, that is, a total of 32 LDs are used as a light source, and the light source spot formed on the phosphor 9 is about 1. It has a substantially square shape of 0 to 1.5 mm. This is because, as described above, when the light density of the light source spot on the phosphor 9 becomes high, the light conversion efficiency decreases due to the luminance saturation phenomenon, or the phosphor 9 deteriorates faster.

If the light source image on the phosphor 9 is made smaller, that is, the pitch of the lens array is made smaller, the size of the light source image formed in the lens cell does not change, and the outer shape of the corresponding lens cell becomes relatively small. Therefore, it is not preferable because the above-mentioned decrease in light utilization efficiency occurs.

F-number F _LD excitation optical path in consideration of the above _{relationship,} when the length of one side of the light source spot and d _phos, the light source optical system preferably satisfies the following conditional expression.

The above conditional expression (5) means that when the F number _FLD of the excitation optical path is 1.0 as in this embodiment, the area of the light source spot is preferably larger than 1.0 mm ^2. There is. This is because, as described above, an increase in the light density of the light source spot on the phosphor 9 causes a problem such as a decrease in light conversion efficiency.

Further conditional expression (5), when the area of the light source spot is greater than 1.0 mm ^2, the larger the F-number F _LD excitation light path, that is meant to reduce the beam diameter D _LD excitation light .. This makes it possible to reduce the area of the dichroic mirror 7 and guide more unconverted light from the condenser lens unit 8 to the illumination optical system.

However, the beam diameter D _LD excitation light is too small, that is, when the F-number F _LD excitation optical path too large, thereby deviate the lower limit of the condition (5). Undesirably lowers the light utilization efficiency size of the light source image formed with the light flux diameter D _LD excitation light too small as previously described second lens plane array 62 is larger than the pitch of the lens cells ..

However, if the area of the light source spot is too large, the performance as a point light source deteriorates. Further F-number F _LD excitation optical path is too small, i.e. when the beam diameter D _LD excitation light is too large dichroic mirror 7 is increased in size, to guide the non-converted light from the condenser lens unit 8 to the illumination optical system Becomes difficult. Therefore, the light source optical system is

Is more preferable.

In this embodiment, the set condition of the light source spot by satisfying (5) the size and the excitation light of the F-number F _LD, i.e. the beam diameter D _LD excitation light to the appropriate relationship. As a result, while suppressing the influence of the light density of the light source spot on the phosphor 9, the enlargement of the dichroic mirror 7 is suppressed, so that more unconverted light from the condenser lens unit 8 is guided to the illumination optical system. It becomes possible. Furthermore, light utilization efficiency becomes a light source image on the second lens surface array 63 is large by too small a beam diameter D _LD of the excitation light can be suppressed from being lowered.

Numerical examples of the present invention are as follows.

[Second Example]
FIG. 8 is a diagram showing a configuration of a light source device as a second embodiment of the present invention. The difference between the first embodiment and the present embodiment is the configuration of the dichroic mirror 7 and the positional relationship between the condenser lens unit 8 and the phosphor 9 with respect to the dichroic mirror 7.

The dichroic mirror 7 in the first embodiment described above has a dichroic surface 71 having a characteristic of reflecting excitation light from a light source 1 and transmitting fluorescent light from a phosphor 9, and a transmitting surface that transmits light regardless of wavelength. It was a configuration with 72.

On the other hand, the dichroic mirror 7 in this embodiment has a dichroic surface 73 having a characteristic of transmitting excitation light from the light source 1 and reflecting fluorescent light from the phosphor 9, and a reflecting surface 74 that reflects light regardless of wavelength. It is a configuration equipped with. When the dichroic mirror 7 having such a configuration is used, the dichroic mirror 7, the condenser lens unit 8, and the phosphor 9 need to be arranged in the direction in which the light flux from the light source 1 travels.

Even with such a configuration, it is possible to guide the white luminous flux to the illumination optical system without providing blue light separately from the light source for excitation light, and a compact light source optical system can be realized. Further, the microlens array 63 can suppress a decrease in the light conversion efficiency of the phosphor 9.

[Third Example]
FIG. 9 is a diagram showing a configuration of a projector (projection type display device) equipped with the light source optical system and the light source device shown in the first embodiment.

Reference numeral 100 denotes a light source device shown in the first embodiment. Of course, the light source device shown in the second embodiment may be used as the light source device 100 in FIG.

Reference numeral 200 denotes an illumination optical system that illuminates the liquid crystal panel 20 (light modulation element) described later using the light flux from the light source device 100. The illumination optical system 200 includes a third fly-eye lens 13a, a fourth fly-eye lens 13b, a polarization conversion element 14, and a condenser lens 15.

The luminous flux from the light source device 100 is divided into a plurality of luminous fluxes by the third fly-eye lens 13a to form a light source image between the fourth fly-eye lens 13b and the polarization conversion element 14. The polarization conversion element 14 is configured to align the polarization directions of the incident light flux in a predetermined direction, and the light flux from the polarization conversion element 14 is guided to the color separation / combining unit 300 by the condenser lens 15.

The color separation / synthesizing unit 300 includes a polarizing plate 16, a dichroic mirror 17, a wavelength-selective retardation plate 18, a red liquid crystal panel 20r, a green liquid crystal panel 20g, and a blue liquid crystal panel 20b. 20g and 20b are collectively referred to as a liquid crystal panel 20. Further, it includes a red λ / 4 plate 19r, a green λ / 4 plate 19g, a blue λ / 4 plate 19b, a first polarization beam splitter 21a, a second polarization beam splitter 21b, and a composite prism 22. The red λ / 4 plate 19r, the green λ / 4 plate 19g, and the blue λ / 4 plate 19b are collectively referred to as the λ / 4 plate 19. Further, the portion of the color separation / synthesis unit 300 excluding the liquid crystal panel 20 is used as the color separation / synthesis system.

The polarizing plate 16 is a polarizing plate that transmits only light in the polarization direction prepared by the polarization conversion element 14, and blue light and red light among the light from the polarizing plate 16 by the dichroic mirror 17 are the second polarization beam splitter 21b. Is guided in the direction of. On the other hand, the green light is directed in the direction of the first polarization beam splitter 21a.

The first polarization beam splitter 21a and the second polarization beam splitter 21b are configured to guide the light from the dichroic mirror 17 to the liquid crystal panel 20 and the light from the liquid crystal panel 20 to the synthesis prism 22 according to the polarization direction. Has been Further, the λ / 4 plate 19 has an effect of enhancing the light detection effect by giving a phase difference of λ / 2 in the round trip due to reflection by the liquid crystal panel 20.

The synthetic prism 22 synthesizes blue light and red light from the second polarizing beam splitter 21a and green light from the second polarizing beam splitter 21b and guides them to the projection optical system 23.

With such a configuration, the projector shown in FIG. 8 can project a color image onto a projected surface such as a screen.

The positional relationship between the light source device 100, the illumination optical system 200, the color separation / combining unit 300, and the projection optical system 23 does not have to be the relationship shown in FIG. Specifically, in FIG. 8, the optical axis of the condenser lens unit 8, the optical axis of the condenser lens 15, the surface normal of the liquid crystal panel 20, and the optical axis of the projection lens 23 all exist in the same plane. There is. However, each axis does not necessarily have to exist in the same plane, and may be appropriately changed so that the existing plane differs depending on the shaft using a mirror or the like.

Although the preferred examples of the present invention have been described above, it goes without saying that the present invention is not limited to these examples, and various modifications and changes can be made within the scope of the gist thereof.

(Other embodiments)
In each of the above-described embodiments, the configuration in which the surface of the microlens array 63 on the concave lens 5 side is the first lens surface array 61 and the surface on the dichroic mirror 7 side is the second lens surface array 62 is illustrated. Such a configuration is preferable because the relative displacement of both lens surface arrays can be suppressed.

However, the present invention is not limited to the above configuration, and instead of the microlens array 63, a first fly-eye lens including a first lens surface array 61 in order from the concave lens 5 side and a second lens surface array 62. A second fly-eye lens may be provided. In this case, the volume at the time of glass molding can be reduced, so that the molding time can be shortened.

Further, although not described in detail in each of the above-described embodiments, the light source 1 and the collimator lens 2 may be held by separate holding members or may be held by the same holding member. For example, an LD bank in which eight light sources 1 and eight collimator lenses 2 are integrated may be used.

Further, instead of the plane mirror 4 shown in each of the above-described embodiments, a prism may be used to guide the light flux from the parabolic mirror array 3 to the concave lens 5.

Further, in each of the above-described embodiments, the configuration in which the light source image is formed on the second lens surface array 62 by the first lens surface array 61 is illustrated, but the light source image is in the vicinity of the second lens surface array 62. It only needs to be formed. In other words, the light source image may be formed between the second lens surface array 62 and the phosphor 9, or between the second lens surface array 62 and the dichroic mirror 7.

Further, in each of the above-described embodiments, the configuration of the phosphor 9 in which the phosphor layer is coated on the aluminum substrate having high reflectance is illustrated, but more specifically, it is continuously continuous in the circumferential direction on the circular aluminum substrate. A wheel coated with a phosphor layer may be rotated by a motor. With such a configuration, the position where the laser light from the light source 1 is focused on the phosphor layer changes, and deterioration of the phosphor layer can be suppressed.

Further, in each of the above-described embodiments, a configuration in which a dichroic surface 71 is provided as a light guide surface is illustrated, but the present invention is not limited to such a configuration. The light fluxes from the plurality of light sources 1 may be aligned in a predetermined polarization direction, and a polarization separation surface may be provided as a light guide surface instead of the dichroic surface 71. Since the luminous flux from the phosphor 9 is emitted in a state where the polarization direction is disturbed, it is possible to guide the luminous flux having the same wavelength as the luminous flux from the light source 1 to the illumination optical system on the polarization separation surface.

1 Light source 8 Condensing lens unit (condensing optical system)
9 Fluorescent material (wavelength conversion element)
61 First lens surface array 62 Second lens surface array 71 Dichroic surface (light guide surface)

Claims (7)

A light source optical system that guides the luminous flux from a light source to a wavelength conversion element.
A first lens plane array with a plurality of first lens planes,
A second lens surface array having a plurality of second lens surfaces and receiving a light flux from the first lens surface array,
A condensing optical system that guides the luminous flux from the second lens surface array to the wavelength conversion element and has positive power,
A light guide surface for guiding a light flux from the second lens surface array to the wavelength conversion element via the condensing optical system is provided.
The luminous flux diameter of the light flux from the second lens surface array is smaller than the luminous flux diameter of the light flux guided from the condensing optical system to the light guide surface.
F-number F _LD of the light converging optical system divided by the beam diameter of the light beam guided to the focal length to the light guide surface from said second lens surface array excitation light path of, is formed on the wavelength converting element When the length of one side of the light source spot is _dphos ,

A light source optical system characterized by satisfying. When the value obtained by dividing the focal length of the condensing optical system by the beam diameter of the light beam guided from the condensing optical system to the light guide surface is defined as the F number of the fluorescent optical path, the F number of the excitation optical path is the fluorescent optical path. light source optical system according to claim 1, wherein the us go larger than the F-number. The fluorescent light path F-number _{F phos,} the F-number of the excitation light path when the _{F LD,}

The light source optical system according to claim 2, wherein the light source optical system is characterized in that. Further comprising a light guide element having the light guide surface and a transmission surface for transmitting the light flux from the wavelength conversion element regardless of the wavelength.
The light guide surface reflects the luminous flux from the light source and guides it to the wavelength conversion element, and the luminous flux from the wavelength conversion element having a wavelength different from that from the light source is in a direction different from that of the light source. light source optical system according to any one of claims 1 to 3, wherein the dichroic surface der Turkey for transmitting to. A light guide element having the light guide surface and a reflection surface that reflects the light flux from the wavelength conversion element regardless of the wavelength is further provided.
The light guide surface transmits the luminous flux from the light source and guides it to the wavelength conversion element, and reflects the luminous flux from the wavelength conversion element whose wavelength is different from that from the light source to the light source. light source optical system according to any one of claims 1 to 3, wherein the dichroic surface der Turkey leading to different directions.
Further satisfaction to the light source optical system according to any one of claims 1 to 5, wherein the Turkey. With the light source
A positive lens provided in the traveling direction of the luminous flux from the light source and
With the wavelength conversion element
The light source optical system according to any one of claims 1 to 6 .
Light modulation element and
An illumination optical system that illuminates the light modulation element using a luminous flux from the light source optical system,
Wherein the light beam from the light source optical system and guides the light modulation element, a projection type display device comprising a benzalkonium comprises a color separating and synthesizing system for guiding the projection optical system the light beam from the optical modulator.