WO2021015101A1

WO2021015101A1 - Display device

Info

Publication number: WO2021015101A1
Application number: PCT/JP2020/027733
Authority: WO
Inventors: 翔吾久保田
Original assignee: ソニー株式会社
Priority date: 2019-07-24
Filing date: 2020-07-16
Publication date: 2021-01-28
Also published as: JPWO2021015101A1

Abstract

This display device is provided with: a plurality of spatial light modulators; a first synthesis prism that synthesizes a plurality of video light beams modulated by the plurality of spatial light modulators; at least one polarization beam splitter that guides the plurality of video light beams modulated by the plurality of spatial light modulators to the first synthesis prism; and at least one first substrate that comprises a material having higher heat conductivity than the first synthesis prism and the polarization beam splitter, and joins the first synthesis prism and the polarization beam splitter.

Description

Display device

The present disclosure relates to a display device suitable for a projector or the like.

For example, a plurality of video lights modulated by a plurality of reflective spatial light modulators are guided to a synthetic prism by a polarizing beam splitter (PBS), and the video light synthesized by the synthetic prism is projected by a projection optical system. Projectors are known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-215491

Optical members such as polarizing beam splitters and synthetic prisms may change the optical characteristics depending on the temperature and deteriorate the display state of the image.

It is desirable to provide a display device that can improve the deterioration of the display state of the image due to the temperature change of the optical member.

The display device according to the embodiment of the present disclosure includes a plurality of spatial light modulators, a first synthetic prism that synthesizes a plurality of video lights modulated by the plurality of spatial light modulators, and a plurality of spatial light modulations. The first synthesis is composed of at least one polarizing beam splitter that guides a plurality of image lights modulated by the vessels to the first synthesis prism, and a material having a higher thermal conductivity than the first synthesis prism and the polarization beam splitter. It includes at least one first substrate that joins the prism and the polarizing beam splitter.

In the display device according to the embodiment of the present disclosure, the first synthetic prism and the polarizing beam splitter are first joined via a first substrate made of a material having high thermal conductivity. Changes in the internal temperature distributions of the synthetic prism and the polarizing beam splitter are suppressed.

FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to the first embodiment of the present disclosure together with an optical path in an all-white display state. It is a characteristic figure which shows the result of simulating the internal temperature distribution of the main part of the projector which concerns on Example 1, which corresponds to the projector which concerns on 1st Embodiment. It is a characteristic diagram which shows the result of simulating the internal temperature distribution of the main part of the projector which concerns on Comparative Example 1. It is a characteristic diagram which shows the result of simulating the internal temperature distribution of the main part of the projector which concerns on Comparative Example 2. FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to the first embodiment together with an optical path in an all-black display state. FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to a second embodiment together with an optical path in an all-white display state. It is a main part block diagram which shows one structural example of the main part of a projector as a display device which concerns on 3rd Embodiment. FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to a fourth embodiment together with an optical path in an all-white display state. FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to a fifth embodiment together with an optical path in an all-white display state. FIG. 5 is an overall configuration diagram showing an example of a configuration of a projector as a display device according to a sixth embodiment together with an optical path in an all-white display state. It is a main part block diagram which shows one structural example of the main part of the projector as a display device which concerns on 7th Embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The explanation will be given in the following order.
0. Comparative example 1. First Embodiment (FIGS. 1 to 5)
1.1 Composition 1.2 Actions and effects 2. Second embodiment (FIG. 6)
2.1 Configuration 2.2 Actions and effects 2.3 Modifications 3. Third Embodiment (Fig. 7)
3.1 Configuration 3.2 Actions and effects 4. Fourth Embodiment (FIG. 8)
4.1 Composition 4.2 Actions and effects 5. Fifth Embodiment (FIG. 9)
5.1 Composition 5.2 Actions and effects 6. Sixth Embodiment (FIG. 10)
6.1 Composition 6.2 Actions and effects 7. Seventh Embodiment (FIG. 11)
7.1 Composition 7.2 Actions and effects 8. Other embodiments

<0. Comparative example>
Patent Document 1 (Japanese Unexamined Patent Publication No. 2001-215491) discloses a technique relating to a reflective liquid crystal projector using a plurality of reflective liquid crystal elements. The reflective liquid crystal projector proposed in Patent Document 1 includes a synthetic prism that synthesizes a plurality of video lights modulated by a plurality of reflective liquid crystal elements, and a plurality of polarizations that guide a plurality of modulated video lights to the synthetic prism. It is equipped with a beam splitter. Further, the reflective liquid crystal projector proposed in Patent Document 1 includes a polarizing plate and a polarizing rotating element between a synthetic prism and a plurality of polarizing beam splitters.

In the technique described in Patent Document 1, the heat generated by the polarizing plate is diffused by arranging a sapphire substrate having high thermal conductivity between the splitter surface of the polarizing beam splitter and the polarizing plate and the polarizing beam splitter. There is. However, when the sapphire substrate is arranged on the splitter surface of the polarizing beam splitter, the sapphire substrate is positioned obliquely with respect to the incident light, so that astigmatism occurs due to the sapphire substrate. Further, by arranging the sapphire substrate, the adhesive layer on the splitter surface is increased, so that astigmatism is further generated. For this reason, the display state of the image is deteriorated, and it becomes difficult to cope with high definition such as 4K resolution.

Further, in the structure described in Patent Document 1, since the amount of heat generated by the polarizing plate is large, it is difficult to cope with high brightness in the structure in which the sapphire substrate is arranged between the polarizing plate and the polarizing beam splitter. The heat generated by the polarizing plate causes the thermal lens effect in the synthetic prism and the polarizing beam splitter.

Further, in the structure described in Patent Document 1, since the thermal resistance of the polarizing plate and the polarizing rotating element is large, the temperature distribution changes between the synthetic prism and the polarizing beam splitter especially when the image is switched between the all-white display and the all-black display. As a result, focus drift with a short time constant occurs due to image switching, and the display state of the image deteriorates.

<1. First Embodiment>
[1.1 Configuration]
(Overview)
FIG. 1 shows an example of a configuration of the projector 1 as a display device according to the first embodiment of the present disclosure, in which red (R) colored light, green (G) colored light, and blue (B) are displayed in an all-white display state. It is shown together with the optical path of each colored light.

The projector 1 includes a light source unit 10, an illumination system 20, a panel core 30, and a projection optical system 40.

The light source unit 10 includes a blue laser diode 11B, a diffuser wheel 12, a laser diode 13 for excitation light, a phosphor wheel 14, a dichroic mirror 15, a condenser lens 16, and a condenser lens 17. There is.

The illumination system 20 includes a first fly-eye lens array 21, a second fly-eye lens array 22, a PS conversion element 23, a condenser lens 24, a dichroic mirror 25, a reflection mirror 26, a half-wave plate 27, and the like. A reflection mirror 28 and a dichroic mirror 29 are provided.

The panel core 30 is joined to a red panel 31R, a green panel 31G, a blue panel 31B, a polarization beam splitter (ch-PBS) 32, a polarization beam splitter (ch-PBS) 33, and a synthetic prism 34. A substrate 35 and a bonding substrate 36 are provided. The red panel 31R, the green panel 31G, and the blue panel 31B are each composed of, for example, a reflective liquid crystal panel (LCOS).

The projection optical system 40 includes a projection lens 41.

The red panel 31R, the green panel 31G, and the blue panel 31B each correspond to a specific example of the "spatial light modulator" in the technology of the present disclosure. Each of ch-PBS32 and ch-PBS33 corresponds to a specific example of a "polarizing beam splitter" in the technique of the present disclosure. The synthetic prism 34 corresponds to a specific example of the "first synthetic prism" in the technique of the present disclosure. The bonded substrate 35 and the bonded substrate 36 each correspond to a specific example of the "first substrate" in the technique of the present disclosure.

In this projector 1, the illumination system 20 generates illumination light having a substantially uniform spatial distribution of illuminance on the panel incident surface of each color for each color of red light, green light, and blue light based on the light from the light source unit 10. To. The red panel 31R, the green panel 31G, and the blue panel 31B are each illuminated by the corresponding illumination light of each color via ch-PBS32 or ch-PBS33. The red panel 31R, the green panel 31G, and the blue panel 31B each modulate the illumination light of each corresponding color based on the video signal. After the modulated video light of each color is finally synthesized by the synthetic prism 34 via the ch-PBS 32 and the bonding substrate 35 or the ch-PBS 33 and the bonding substrate 36 by utilizing the difference in polarization and wavelength band. , Projected onto a projection surface such as a screen (not shown) by the projection optical system 40.

(Structure of each part)
The light source unit 10 emits light including a plurality of colored lights that are sources of illumination light for the panel core 30 toward the illumination system 20. FIG. 1 shows an example of emitting light including red light, green light, and blue light as a plurality of colored lights. In the light source unit 10, the blue light emitted from the blue laser diode 11B is diffused by the diffuser wheel 12, condensed by the condenser lens 16, and then transmitted through the dichroic mirror 15 and incident on the illumination system 20. The laser diode 13 for excitation light emits blue light as excitation light. The blue light emitted from the excitation light laser diode 13 passes through the dichroic mirror 15 and is then focused by the condenser lens 17 toward the phosphor wheel 14. The phosphor wheel 14 is provided with a phosphor that is excited by blue light to emit yellow light including red light and green light. The yellow light including the red light and the green light generated by the phosphor wheel 14 is condensed toward the dichroic mirror 15 by the condenser lens 17, and then reflected by the dichroic mirror 15 and incident on the illumination system 20.

The light source unit 10 is not limited to the configuration using the laser light source and the phosphor shown in FIG. 1, and may be configured to use a halogen lamp, a high-pressure mercury lamp, an LED (light emitting diode), or the like.

The illumination system 20 generates uniform illumination light based on the light from the light source unit 10 and emits it toward the panel core 30. The blue light emitted from the light source unit 10 and the yellow light including the red light and the green light are divided by the first fly-eye lens array 21 and the second fly-eye lens array 22 of the illumination system 20, and then the PS conversion element. By passing through 23, the polarization state is aligned in one direction (S polarization in the example of FIG. 1). The S-polarized blue light and yellow light are incident on the dichroic mirror 25 via the condenser lens 24.

The dichroic mirror 25 transmits the incident blue light. After that, the blue light is reflected by the reflection mirror 28, passes through the dichroic mirror 29, and is incident on the polarization separation membrane of ch-PBS32 in the panel core 30 in an S-polarized state.

Further, the dichroic mirror 25 reflects the red light contained in the incident yellow light and transmits the green light contained in the yellow light. After that, the green light is reflected by the reflection mirror 28 and the dichroic mirror 29, and is incident on the polarization separation membrane of ch-PBS 33 in the panel core 30 in an S-polarized state. Further, the red light is converted into P-polarized light by being reflected by the reflection mirror 26 and then passing through the half-wave plate 27. The red light converted to P-polarized light is reflected by the dichroic mirror 29 and is incident on the polarization separation membrane of ch-PBS32 in the panel core 30 in a P-polarized state.

The half-wave plate 27 is, for example, a film half-wave plate. In the projector 1, only red light is incident on the half-wave plate 27 of the illumination light, and the energy density (W / cm ² ) of the light can be suppressed to be relatively small. Therefore, an organic material such as polyolefin or polycarbonate can be used as the film half-wave plate.

The lighting system 20 is not limited to the configuration of the fly-eye lighting system shown in FIG. 1, and may be a critical lighting system, a Koehler lighting system, a rod integrator lighting system, or the like. Further, the light source unit 10 and the illumination system 20 may include a diffuser plate and a beam shaping element for shaping the luminous flux into a desired angular distribution.

In the panel core 30, the ch-PBS 32 and the bonding substrate 35 are arranged on the optical path (RB-ch) of red light and blue light. The bonding substrate 35 is made of a material having a higher thermal conductivity than the synthetic prism 34 and ch-PBS 32, and bonds the synthetic prism 34 and ch-PBS 32. The ch-PBS 33 and the bonding substrate 36 are arranged on the optical path (G-ch) of green light. The bonding substrate 36 is made of a material having a higher thermal conductivity than the synthetic prism 34 and ch-PBS 33, and bonds the synthetic prism 34 and ch-PBS 33.

The ch-

PBS

32, 33 and the synthetic prism 34 may be integrated with a spacer for adjusting the air-equivalent distance (back focus) from the panel of each color to the exit surface of the panel core 30.

Further, the panel core 30 may further include a compensation plate (retarder) (not shown). In this case, the retarder, for example, between ch-PBS32 and the red panel 31R, ch-PBS32 and blue to compensate for the phase difference due to the skew rays of ch-PBS32 and ch-PBS33 and the pre-tilt of the panel liquid crystal. It is arranged between the panel 31B and between the ch-PBS 33 and the green panel 31G. As the retarder, a known retardation plate can be used.

In the projector 1, the bonding substrate 35 arranged on the optical path (RB-ch) of red light and blue light has optical characteristics as a half-wave plate (phase difference plate with a phase difference of 90 °), and red light. And the direction in which the polarization direction of blue light is rotated by 90 ° is arranged. Such optical characteristics are usually obtained by a laminate of dielectrics having birefringence, for example, a laminate of two quartz substrates. For materials other than quartz, sapphire and the like are preferably used. The thermal conductivity (W / (m · K)) of quartz is 8 and that of sapphire is 41.

The optical characteristics of the synthetic prism 34 are appropriately selected according to the optical characteristics of the bonding substrate 36 arranged on the optical path (G-ch) of green light. When the bonding substrate 36 on the G-ch side does not have an optic axis or is arranged in an orientation that does not affect the polarization direction of green light, the composite prism 34 is a dichroic prism that reflects the green band. Can be used. As a material having no optical axis, diamond, spinel, or the like can be used. Diamond has a thermal conductivity of 1000 and spinel has a thermal conductivity of 16.

When the bonding substrate 36 on the G-ch side has optical characteristics as a half-wave plate (phase difference plate with a phase difference of 90 °) like the bonding substrate 35 on the RB-ch side, the composite prism 34 has blue light. It may be a dichroic PBS that transmits both P-polarized light and S-polarized light, and transmits P-polarized light and reflects S-polarized light for red light and green light. Higher contrast can be obtained with dichroic PBS.

Optical glass is used as the material for ch-

PBS

32, 33 and the synthetic prism 34. Specifically, for ch-

PBS

32, 33, for example, PBH56 (OHARA) is used. The thermal conductivity of PBH56 is 0.635. As the synthetic prism 34, for example, S-BSL7 (OHARA) is preferably used in the case of a dichroic prism, and PBH56 is preferably used in the case of a dichroic PBS. The reason why PBH56 is used is that it has a high refractive index and a small photoelastic constant. When the refractive index is high, the back focus in the panel core 30 becomes short, which can contribute to the miniaturization of the optical system in the projector 1. Further, since the degree of freedom in designing the optical thin film is increased, a highly functional optical thin film such as dichroic PBS can be imparted. When the photoelastic constant is small, the occurrence of unevenness (hereinafter referred to as black unevenness) in the black display portion due to birefringence caused by the stress inside the glass material is suppressed, and high contrast can be obtained. The reason why S-BSL7 is used for a dichroic prism is that the temperature coefficient of refractive index (dn / dT) is low and it is inexpensive. When dn / dT is small, focus drift is suppressed. Other glass materials may be used as long as the above points are satisfied.

The thermal conductivity of optical glass, which is the material of ch-

PBS

32, 33 and synthetic prism 34, is generally 1 or less. Therefore, the thermal conductivity of the materials of the

bonding substrates

35 and 36 is more than 1, preferably 5 or more.

The thickness of the bonding substrate 35 on the RB-ch side and the bonding substrate 36 on the G-ch side and the number of laminated substrates may be the same or different, but the back focus is RB-ch and G-ch. It is preferable that the lengths of ch-

PBS

32, 33 and the synthetic prism 34 are designed so as to have substantially the same length. For example, an acrylic, acrylic urethane, or epoxy adhesive is used for joining the synthetic prism 34 and ch-PBS 32 by the bonding substrate 35 and joining the synthetic prism 34 and ch-PBS 33 by the bonding substrate 36. Can be done. The same applies to the bonding of a plurality of optical glasses constituting ch-

PBS

32, 33, the bonding of a plurality of optical glasses constituting the synthetic prism 34, and the bonding of a plurality of substrates constituting the

bonding substrates

35, 36. Adhesives can be used.

[1.2 Actions and effects]
According to the projector 1 according to the first embodiment, the synthetic prism 34 and the ch-

PBS

32, 33 are joined via the

bonding substrates

35, 36 made of a material having high thermal conductivity. As described below, changes in the internal temperature distributions of the synthetic prism 34 and ch-

PBS

32, 33 are suppressed, and it is possible to improve the deterioration of the image display state due to the temperature change of the optical members. It becomes.

Further, according to the projector 1 according to the first embodiment, as compared with the reflective liquid crystal projector according to the above-mentioned comparative example, a substrate that is diagonally arranged with respect to the incident light is not used, so that the 4K resolution and the like It can correspond to high definition. Further, as compared with the reflective liquid crystal projector according to the comparative example, since the polarizing plate is not arranged between the synthetic prism 34 and ch-

PBS

32, 33, the bonding between the synthetic prism 34 and ch-

PBS

32, 33 is formed. The heat generation of the part is suppressed, and it is possible to cope with high brightness. In the projector 1 according to the first embodiment, the synthetic prism 34 and the ch-

PBS

32, 33 are bonded only via the

bonding substrates

35, 36 made of a material having high thermal conductivity. As will be described below, the fluctuation of the temperature distribution when switching the image between the white display and the black display becomes small, and the focus drift with a short time constant due to the image switching can be suppressed.

Further, according to the projector 1 according to the first embodiment, since an inexpensive resin film can be used for the half-wave plate 27 arranged on the incident side of the panel core 30, cost cutting can be realized.

Note that the effects described in this specification are merely examples and are not limited, and other effects may be obtained. The same applies to the effects of the other embodiments thereafter.

(About the occurrence of focus drift)
The shape of the spatial distribution of the luminous flux propagating through each optical member constituting the optical system in the projector 1 is circular immediately after the second fly-eye lens array 22 is emitted, and rectangular immediately before the panel core 30 is incident on each panel. Immediately before the incident on the lens 41, it becomes an ellipse. In addition, each optical member absorbs light (particularly blue light) and generates heat (heat relaxation) according to the internal transmittance of each optical member. Further, a non-uniform temperature distribution occurs in each optical member according to the thermal conductivity of each optical member. Therefore, a refractive index distribution (thermal lens effect) is generated in each optical member according to the temperature coefficient of the refractive index (dn / dT). This thermal lens causes focus drift. It is visually recognized by the observer as a blur (deterioration of resolution) of the image.

Here, FIG. 5 shows an example of the configuration of the projector 1 together with the optical path in the all-black display state. When the average luminance level of the image is high as in the case of the all-white display shown in FIG. 1, a thermal lens is generated in the ch-

PBS

32, 33 and the synthetic prism 34. When the image is switched from this state to an image having a low average luminance level as in the case of the all-black display shown in FIG. 5, the reflected light from each panel is reflected by the polarizing separation films of ch-PBS32 and 33 to the light source portion 10 side. Therefore, the power (refractive power) of the thermal lens of ch-

PBS

32, 33 increases, and the power of the thermal lens of the synthetic prism 34 decreases. The influence of the power fluctuation is larger in the composite prism 34, and the power of the panel core 30 as a whole is smaller. When the dn / dT of ch-

PBS

32, 33 and the synthetic prism 34 is positive, when the power becomes small, a focus drift occurs in the direction in which the image plane on the projection lens 41 side moves to the back. On the contrary, when switching from the black display to the white display, a focus drift in the direction of moving toward the front occurs.

(Effect of suppressing focus drift by bonding substrates 35 and 36)
In the projector 1, since the ch-

PBS

32, 33 and the synthetic prism 34 are bonded via the

bonding substrates

35, 36, heat is transferred from the central portion having a high temperature to the peripheral portion inside the

bonding substrates

35, 36. The temperature gradient between the ch-

PBSs

32 and 33 and the synthetic prism 34 is reduced. As a result, the generation of the thermal lens is suppressed, so that the focus drift is suppressed.

Further, when the display is black, heat is concentrated on ch-

PBS

32, 33, but since heat is transferred from ch-

PBS

32, 33 to the synthetic prism 34 through the

bonding substrates

35, 36, ch-

PBS

32, 33 and the synthetic prism 34 Is a separate body (comparative example 2 described later), a member having a large thermal resistance between ch-

PBS

32, 33 and the synthetic prism 34 (for example, a wavelength plate made of an organic material) or a member serving as a heat generating source (for example). Compared with the case where the absorption type polarizing plate) is inserted (Comparative Example 1 described later), when the image is switched from the white display to the black display, the ch-

PBS

32, 33 and the synthetic prism 34 are respectively. The fluctuation of power becomes small, and as a result, the fluctuation of power of the panel core 30 as a whole becomes small. That is, focus drift is suppressed. The observer can see an image in which the resolution does not deteriorate regardless of the transition of the average brightness level.

(Simulation of temperature distribution)
FIG. 2 shows the result of simulating the internal temperature distribution of the main part of the projector according to the first embodiment corresponding to the projector 1 according to the first embodiment. FIG. 3 shows the result of simulating the internal temperature distribution of the main part of the projector according to Comparative Example 1. FIG. 4 shows the result of simulating the internal temperature distribution of the main part of the projector according to Comparative Example 2.

For simplicity, the simulations of FIGS. 2 to 4 were calculated using a system of 1 panel and 2 PBS. This corresponds to, for example, the system of the blue panel 31B, ch-PBS32, bonding substrate 35, and synthetic prism 34 in the projector 1. In the simulations of FIGS. 2 to 4, light rays were traced from the light source unit 10 at the time of full white display in the projector 1 to the system corresponding to the exit surface of the composite prism 34 via the illumination system 20. From the results of ray tracing, the calorific value q [W / m ³ ] per unit volume, which is proportional to the luminous flux, was defined in the form of q = f (x, y, z). In Example 1 and Comparative Examples 1 and 2, the thermal conductivity coefficients of the two PBSs corresponding to ch-PBS32, the bonding substrate 35 and the synthetic prism 34 were set as follows. In the simulations of FIGS. 2 to 4, thermo-fluid analysis was performed to obtain the temperature distribution inside the system in the steady state. In addition, the contour lines of the temperature distribution were counted.

(Example 1)
Example 1 has a configuration in which ch-PBS32 and two PBSs corresponding to the synthetic prism 34 are bonded via a crystal substrate corresponding to the bonding substrate 35. The thermal conductivity of the crystal substrate was 8 W / (m · K). The glass material of PBS corresponding to ch-PBS32 and synthetic prism 34 was PBH56, and the thermal conductivity was 0.635 W / (m · K).

(Comparative Example 1)
In Comparative Example 1, the ch-PBS 32 and the two PBSs corresponding to the synthetic prism 34 are bonded to each other without providing the crystal substrate corresponding to the bonding substrate 35. The glass material of PBS corresponding to ch-PBS32 and synthetic prism 34 was PBH56, and the thermal conductivity was 0.635 W / (m · K).

(Comparative Example 2)
Comparative Example 2 has a configuration in which two PBSs corresponding to ch-PBS 32 and a synthetic prism 34 are arranged as separate bodies without providing a crystal substrate corresponding to the bonding substrate 35. The glass material of the optical member corresponding to ch-PBS32 and the synthetic prism 34 was PBH56, and the thermal conductivity was 0.635 W / (m · K).

As can be seen from the simulation results of FIGS. 2 to 4, the structure in which two PBSs are joined to each other via a crystal substrate (Example 1) has a smaller number of temperature contour lines across the PBS cross section. .. Further, the length of the thermal lens is shorter in the structure of the first embodiment. As a result, the power of the thermal lens at the time of all-white display is reduced, and focus drift is suppressed.

<2. Second Embodiment>
Next, the display device according to the second embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to the first embodiment will be designated by the same reference numerals, and description thereof will be omitted as appropriate.

[2.1 Configuration]
FIG. 6 shows an example of the configuration of the projector 1A as the display device according to the second embodiment together with the optical paths of the red light, the green light, and the blue light in the all-white display state.

The projector 1A according to the second embodiment includes a lighting system 20A instead of the lighting system 20 in the projector 1 according to the first embodiment. Further, the projector 1A according to the second embodiment includes a panel core 30A instead of the panel core 30 in the projector 1 according to the first embodiment.

The lighting system 20A includes a first fly-eye lens array 21, a second fly-eye lens array 22, a PS conversion element 23, a condenser lens 24, and a dichroic mirror 25A. The configuration of the first fly-eye lens array 21 to the condenser lens 24 in the illumination system 20A is the same as that of the illumination system 20 in the first embodiment.

In the illumination system 20A, the dichroic mirror 25A reflects the incident S-polarized blue light and the S-polarized red light contained in the incident yellow light toward ch-PBS32 in the panel core 30A. Further, the dichroic mirror 25A transmits the incident S-polarized green light toward ch-PBS 33 in the panel core 30.

The panel core 30A includes a red panel 31R, a green panel 31G, a blue panel 31B, ch-PBS32, ch-PBS33, a synthetic prism 34, a bonding substrate 35, and a bonding substrate 36. ..

The panel core 30A further includes an incident side substrate 37. ch-PBS32 has an incident surface of light. The incident side substrate 37 is made of a material having a higher thermal conductivity than that of ch-PBS32, and is bonded to the incident surface of light of ch-PBS32. The thermal conductivity of optical glass, which is the material of ch-PBS32, is generally 1 or less. Therefore, the thermal conductivity of the material of the incident side substrate 37 is more than 1, preferably 5 or more.

The incident side substrate 37 corresponds to a specific example of the "second substrate" in the technique of the present disclosure.

In the panel core 30A, the incident side substrate 37, ch-PBS 32, and the bonding substrate 35 are arranged on the optical path (RB-ch) of red light and blue light.

In the panel core 30A, the incident side substrate 37 and the bonding substrate 35 arranged on the RB-ch side act as a half-wave plate for red light and optics as a wavelength-selective wave plate that does not give a phase difference to blue light. It has characteristics, and each is arranged so that the polarization direction of red light is rotated by 90 °. Such optical characteristics are usually obtained by a laminate of dielectrics having birefringence, for example, a laminate of three quartz substrates. Sapphire or the like is preferably used as a material other than quartz.

In the panel core 30A, both red light and blue light are incident on the polarization separation membrane of the synthetic prism 34 in a P-polarized state by passing through the bonding substrate 35.

In the panel core 30A, the bonding substrate 36 on the G-ch side has optical characteristics as a half-wave plate. By passing through the bonding substrate 36, the green light is incident on the polarization separation membrane of the synthetic prism 34 in an S-polarized state.

In the panel core 30A, as the synthetic prism 34, PBS that transmits P-polarized light and reflects S-polarized light is used for three colored lights of red light, green light, and blue light.

Similar to the panel core 30 in the first embodiment, the air-equivalent distance (back focus) from the panel of each color to the exit surface of the panel core 30A is approximately the same length for RB-ch and G-ch. , Ch-

PBS

32, 33 and synthetic prism 34 are preferably designed in length. As the material of ch-

PBS

32, 33 and the synthetic prism 34, the same optical glass as the panel core 30 in the first embodiment can be used.

In the projector 1A according to the second embodiment, since the incident side substrate 37 having optical characteristics as a wavelength selective wave plate is arranged on the incident surface of the RB-ch in the panel core 30A, the dichroic mirror is arranged in the illumination system 20A. The optical system on the light source side of 25A may be one white system.

[2.2 Actions and effects]
According to the projector 1A according to the second embodiment, the incident side substrate 37 made of a material having a higher thermal conductivity than that of ch-PBS32 is bonded to the incident surface of ch-PBS32. Heat is transferred from the high temperature central portion to the peripheral portion inside the side substrate 37, and the temperature gradient of ch-PBS 32 is further reduced. As a result, focus drift is further suppressed.

Further, according to the projector 1A according to the second embodiment, since the incident side substrate 37 is provided with the optical characteristics as a wavelength selective wave plate, the optical system in the stage before the dichroic mirror 25A is white 1. It can be made into a system, and the configuration of the lighting system 20A can be miniaturized.

Other configurations, operations and effects may be substantially the same as those of the display device according to the first embodiment.

[2.3 Deformation example]
Hereinafter, a modification of the projector 1A according to the second embodiment will be described.

(Modification example 1)
In the projector 1A, the ch-

PBS

32, 33 and the synthetic prism 34 are not limited to PBH56 (OHARA) and S-BSL7 (OHARA), and optical glass of other materials may be used.

For example, the synthetic prism 34 includes S-LAH97, S-LAL19, S-LAL12, S-LAL7, S-LAL18, S-BSM18, S-BSM10, S-BSM4, or S-BSM14 (all OHARA). Optical glass as a material may be used. These materials satisfy the conditions that the refractive index nd at a wavelength of 587.56 nm (d line) is nd ≧ 1.6 and the photoelastic constant β is β <2.79. Further, the internal transmittance τ460 having a thickness of 10 mm at a wavelength of 460 nm is τ460 ≧ 0.995, and the temperature coefficient dn / dT of the refractive index in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 586.29 nm (D line) is | dn /. The condition of dT | ≦ 5 is satisfied. The material of the synthetic prism 34 may be a material other than the above-mentioned optical glass as long as these conditions are satisfied.

The above-mentioned condition of refractive index nd is effective in shortening the back focus in the panel core 30A, and the condition of photoelastic constant β is effective in suppressing black unevenness. Further, the condition of the internal transmittance τ460 is effective in suppressing the temperature rise due to the absorption of blue light, and the condition of the temperature coefficient dn / dT of the refractive index is effective in suppressing the focus drift accompanying the temperature rise.

Further, as long as black unevenness is allowed, the same material as the synthetic prism 34 described above may be used as the material for ch-

PBS

32, 33.

According to the modification 1 described above, as the ch-

PBS

32, 33 and the synthetic prism 34, optical glass made of a material having a small calorific value due to absorption of blue light and a small temperature coefficient dn / dT of the refractive index is used. As a result, the temperature gradients of ch-

PBS

32, 33 and the synthetic prism 34 are further reduced, and the focus drift is further suppressed.

(Modification 2)
In the projector 1A, one of ch-PBS32 and the synthetic prism 34 is made of a material having a negative temperature coefficient dn / dT of the refractive index in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or a wavelength of 586.29 nm. The other may be a positive material. Similarly, one of ch-PBS33 and synthetic prism 34 is made of a material having a negative temperature coefficient of refractive index dn / dT in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or 586.29 nm. May be used as a positive material.

For example, DGT1 (CDGM) may be used as a material for one of ch-

PBS

32, 33 and synthetic prism 34. DGT1 satisfies the condition that the temperature coefficient dn / dT of the refractive index in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or a wavelength of 586.29 nm is negative. As long as this condition is satisfied, a material other than DGT1 may be used, but the refractive index nd is high (for example, nd ≧ 1.6) and the photoelastic constant β is small (for example, β <2.79). ) Is more preferable.

According to the modification 2 described above, one of the ch-

PBS

32, 33 and the synthetic prism 34 is made of a material satisfying the condition that the temperature coefficient dn / dT of the refractive index is negative, and the other is positive dn / dT. Since the material satisfying the above conditions is used, the thermal lens effect generated in the ch-

PBS

32, 33 and the synthetic prism 34 is canceled, and the focus drift is further suppressed.

(Modification 3)
In the projector 1A, for example, a silicone-based adhesive may be used for joining the synthetic prism 34 and ch-PBS 32 by the bonding substrate 35 and joining the synthetic prism 34 and ch-PBS 33 by the bonding substrate 36. Similarly, for joining the incident side substrate 37 and ch-PBS 32, for example, a silicone-based adhesive may be used. Similarly, a plurality of optical glasses constituting ch-

PBS

32, 33 are bonded to each other, a plurality of optical glasses constituting a synthetic prism 34 are bonded to each other, and a plurality of

bonding substrates

35, 36 and an incident side substrate 37 are formed. A silicone-based adhesive can also be used for joining the substrates of the above.

According to the modification 3 described above, a silicone-based adhesive having a higher transmittance in the blue band than an acrylic-based adhesive or the like is used for the joint portion of each portion of the panel core 30A. The amount of heat generated is reduced, the generation of thermal lenses is suppressed, and focus drift is further suppressed. According to the third modification, since the blue light transmittance of the joint portion is high (the absorption of blue light is small), the progress of photodegradation of the joint portion is slowed down, and the light resistance of the panel core 30A can be improved.

(Modification example 4)
In the projector 1A, the bonding of the synthetic prism 34 and ch-PBS 32 by the bonding substrate 35 and the bonding of the synthetic prism 34 and ch-PBS 33 by the bonding substrate 36 may be performed by an inorganic bonding process. Similarly, the incident side substrate 37 and ch-PBS 32 may be bonded by an inorganic bonding process. Similarly, a plurality of optical glasses constituting ch-

PBS

bonding substrates

35, 36 and an incident side substrate 37 are formed. The bonding between the substrates may be performed by an inorganic bonding process.

The inorganic bonding process specifically refers to plasma activation bonding, fusion bonding, atomic diffusion bonding, inorganic sol-gel method, and the like. The joints obtained by the inorganic bonding process do not contain resin. Component analysis of the joint is performed by XPS (X-ray Photoelectron Spectroscopy), SEM (Scanning Electron Microscope) -EDS (Energy Dispersive X-ray Spectroscopy), TOF between the cross section of the joint or the mechanically exposed joint layers. -It is possible by various surface analyzes such as SIMS (Time-of-Flight Secondary Ion Mass Spectrometry).

According to the modification 4 described above, since the bonding of each part in the panel core 30A is performed by the inorganic bonding process, the transmittance of the blue band of the bonding portion is higher than that in the case of using an acrylic adhesive or the like. It gets higher. Therefore, the amount of heat generated at the joint is reduced, the generation of the thermal lens is suppressed, and the focus drift is further suppressed. According to the third modification, since the blue light transmittance of the joint portion is high (the absorption of blue light is small), the progress of photodegradation of the joint portion is slowed down, and the light resistance of the panel core 30A can be improved.

<3. Third Embodiment>
Next, the display device according to the third embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to the first or second embodiment will be designated by the same reference numerals, and description thereof will be omitted as appropriate.

[3.1 Configuration]
FIG. 7 shows a configuration example of a main part of the projector 1B as a display device according to the third embodiment. FIG. 7A shows a state in which the main part of the projector 1B is viewed from the upper surface direction. FIG. 7B shows a state in which the main part of the projector 1B is viewed from the side surface. FIG. 7C shows a state in which the main part of the projector 1B is viewed from the front direction.

The projector 1B according to the third embodiment includes a panel core 30B instead of the panel core 30A in the projector 1A according to the second embodiment.

Further, the projector 1B according to the third embodiment includes a temperature control unit 50, a heating member 51, and a cooling member 52.

The heating member 51 and the cooling member 52 correspond to a specific example of the "temperature control member" in the technique of the present disclosure.

In the projector 1B according to the third embodiment, a part of the

bonding substrates

35 and 36 in the panel core 30B protrudes from the bonding portion between the ch-

PBS

32 and 33 and the synthetic prism 34 and is exposed to the outside. A part of the

bonding substrates

35 and 36 projects in the cross-sectional direction of the light flux passing through the

bonding substrates

35 and 36 and the synthetic prism 34.

The heating member 51 and the cooling member 52 are provided so as to thermally act on at least one of ch-

PBS

32, 33, the

bonding substrate

35, 36, the incident side substrate 37, and the synthetic prism 34, respectively. .. It is preferable that the heating member 51 and the cooling member 52 are provided so as to thermally act on the protruding portions of the

bonding substrates

35 and 36, respectively. As the cooling member 52, a member by a known technique such as a fan, a water cooling mechanism, or a Peltier element can be used. As the heating member 51, a member made of a known technique such as a hot air heater or a heating wire can be used.

The temperature control unit 50 controls the temperature by the heating member 51 and the cooling member 52, for example, based on the temperature detection result by a temperature sensor (not shown) provided in the projector 1B. In addition, the temperature control unit 50 may perform temperature control by the heating member 51 and the cooling member 52 in conjunction with the operating time of the projector 1B, the video signal, or the panel drive signal.

[3.2 Actions and effects]
According to the projector 1B according to the third embodiment, since a part of the

bonding substrates

35 and 36 is configured to protrude from the bonding portion between the ch-

PBS

32 and 33 and the synthetic prism 34, the

bonding substrates

35 and 36 Heat transport from the central part to the peripheral part is further promoted, and focus drift is further suppressed. Further, by adopting a structure that projects from the joint portion, it becomes easy for the heating member 51 and the cooling member 52 as the temperature control member to thermally act on the

joint substrates

35 and 36. According to the projector 1B according to the third embodiment, the temperature control member further reduces the temperature gradient between the ch-

PBS

32, 33 and the synthetic prism 34, and further reduces the focus drift.

Other configurations, operations and effects may be substantially the same as those of the display device according to the second embodiment.

<4. Fourth Embodiment>
Next, the display device according to the fourth embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to any one of the first to third embodiments will be designated by the same reference numerals, and description thereof will be omitted as appropriate.

[4.1 Configuration]
FIG. 8 shows an example of the configuration of the projector 1C as the display device according to the fourth embodiment together with the optical paths of the red light, the green light, and the blue light in the all-white display state.

The projector 1C according to the fourth embodiment includes a panel core 30C instead of the panel core 30A in the projector 1A according to the second embodiment.

The panel core 30C further includes an emission side substrate 38 with respect to the configuration of the panel core 30A in the second embodiment.

The emitting side substrate 38 corresponds to a specific example of the "third substrate" in the technique of the present disclosure.

The synthetic prism 34 has a light emitting surface. The emitting side substrate 38 is made of a material having a higher thermal conductivity than that of the synthetic prism 34, and is bonded to the light emitting surface of the synthetic prism 34. The emitting side substrate 38 has optical characteristics as a wavelength-selective wave plate that acts as a half-wave plate for green light and does not give a phase difference to red light and blue light, and the polarization direction of green light is different. It is arranged so that it rotates 90 °. Such optical characteristics are usually obtained by a laminate of dielectrics having birefringence, for example, a laminate of three quartz substrates. Sapphire or the like is preferably used as a material other than quartz. By arranging the wavelength selective wave plate on the exit surface of the synthetic prism 34, as shown in FIG. 8, the image light of each color is emitted from the projection lens 41 in a state where the polarization directions are aligned.

The composite prism 34 and the exit side substrate 38 can be bonded by the same method as the bonding between the

bonding substrates

35 and 36 and the composite prism 34 in the second embodiment or the modified example thereof. Further, the bonding between the plurality of substrates constituting the emitting side substrate 38 can be performed in the same manner as the bonding between the plurality of substrates constituting the incident side substrate 37.

[4.2 Actions and Effects]
According to the projector 1C according to the fourth embodiment, the exit side substrate 38 made of a material having a higher thermal conductivity than that of the composite prism 34 is joined to the exit surface of the composite prism 34. Heat is transferred from the central portion having a high temperature to the peripheral portion inside the side substrate 38, and the temperature gradient of the synthetic prism 34 is further reduced. As a result, focus drift is further suppressed.

Further, according to the projector 1C according to the fourth embodiment, the polarization directions of the image lights of each color emitted from the projection lens 41 can be aligned, so that the specular component (or the regular reflection component in the case of the reflection surface) is present. Color unevenness that often occurs on a projection surface with a low degree of depolarization is reduced. Further, since the polarization directions of the image lights of each color emitted from the projection lens 41 can be aligned, it is possible to provide a 3D image in combination with a known glasses-type device.

Other configurations, operations and effects may be substantially the same as those of the display device according to the second or third embodiment.

<5. Fifth Embodiment>
Next, the display device according to the fifth embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to any one of the first to fourth embodiments will be designated by the same reference numerals, and description thereof will be omitted as appropriate.

[5.1 Configuration]
FIG. 9 shows an example of the configuration of the projector 1D as the display device according to the fifth embodiment together with the optical paths of the red light, the green light, and the blue light in the all-white display state.

The projector 1D according to the fifth embodiment includes a panel core 30D instead of the panel core 30A in the projector 1A according to the second embodiment.

The panel core 30D further includes an emission side substrate 39 with respect to the configuration of the panel core 30A in the second embodiment.

The emitting side substrate 39 corresponds to a specific example of the "third substrate" in the technique of the present disclosure.

The synthetic prism 34 has a light emitting surface. The emitting side substrate 39 is made of a material having a higher thermal conductivity than that of the synthetic prism 34, and is bonded to the light emitting surface of the synthetic prism 34. The emitting side substrate 39 has optical characteristics as a depolarizing element that eliminates polarized light by giving different phase differences to light in the red band and green band depending on the wavelength. Such optical properties are usually obtained with a dielectric having birefringence, such as a single quartz substrate. Sapphire or the like is preferably used as a material other than quartz. By arranging the depolarizing element on the emitting surface of the synthetic prism 34, as shown in FIG. 9, the image light other than the blue light is emitted from the projection lens 41 in a substantially unpolarized state.

The composite prism 34 and the exit side substrate 39 can be bonded by the same method as the bonding between the

bonding substrates

35 and 36 and the composite prism 34 in the second embodiment or a modification thereof.

[5.2 Actions and effects]
According to the projector 1D according to the fifth embodiment, the exit side substrate 39 made of a material having a higher thermal conductivity than that of the composite prism 34 is joined to the exit surface of the composite prism 34, so that the light is emitted. Heat is transferred from the central portion having a high temperature to the peripheral portion inside the side substrate 39, and the temperature gradient of the synthetic prism 34 is further reduced. As a result, focus drift is further suppressed.

The projector 1D according to the fifth embodiment is suitable when the projection lens 41 is an ultrashort focus lens because polarization is eliminated by removing blue light by the emission side substrate 39 as a polarization elimination element. .. Ultra-short focus lenses have a large incident angle with respect to the projection surface, and the range that can be taken by the incident angle tends to be large depending on the angle of view, so the difference in reflectance between P-polarized light and S-polarized light becomes large, and polarization is eliminated. If not, uneven brightness and uneven color are likely to occur. For the same reason, the projector 1D according to the fifth embodiment can be suitably used for a projection surface having a low degree of depolarization.

<6. 6th Embodiment>
Next, the display device according to the sixth embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to any one of the first to fifth embodiments will be designated by the same reference numerals, and description thereof will be omitted as appropriate.

[6.1 configuration]
FIG. 10 shows an example of the configuration of the projector 1E as the display device according to the sixth embodiment together with the optical paths of the red light, the green light, and the blue light in the all-white display state.

The projector 1E according to the sixth embodiment includes a lighting system 20E instead of the lighting system 20 in the projector 1 according to the first embodiment. Further, the projector 1E according to the sixth embodiment includes a panel core 30E instead of the panel core 30 in the projector 1 according to the first embodiment.

The illumination system 20E includes a first fly-eye lens array 21, a second fly-eye lens array 22, a PS conversion element 23, a condenser lens 24,

dichroic mirrors

61A and 61B, a reflection mirror 62, and a reflection mirror 63. , The dichroic mirror 64 is provided. The configuration of the first fly-eye lens array 21 to the condenser lens 24 in the illumination system 20E is the same as that of the illumination system 20 in the first embodiment.

The panel core 30E includes a red panel 31R, a green panel 31G, a blue panel 31B, a red polarizing beam splitter (Rch-PBS) 32R, a green polarizing beam splitter (Gch-PBS) 32G, and blue. It is equipped with a polarizing beam splitter (Bch-PBS) 32B. Further, the panel core 30E includes a synthetic prism 34E, a red bonding substrate 35R, a green bonding substrate 35G, and a blue bonding substrate 35B.

Rch-PBS32R, Gch-PBS32G, and Gch-PBS32B each correspond to a specific example of a "polarizing beam splitter" in the technique of the present disclosure. The synthetic prism 34E corresponds to a specific example of the "first synthetic prism" in the technique of the present disclosure. The red bonding substrate 35R, the green bonding substrate 35G, and the blue bonding substrate 35B each correspond to a specific example of the "first substrate" in the technique of the present disclosure.

In this projector 1E, the illumination system 20E generates illumination light having a substantially uniform spatial distribution of illuminance on the panel incident surface of each color for each color of red light, green light, and blue light based on the light from the light source unit 10. To. The red panel 31R is illuminated by red illumination light via the Rch-PBS32R. The green panel 31G is illuminated by green illumination light via Gch-PBS32G. The blue panel 31B is illuminated by blue illumination light via Bch-PBS32B. The red panel 31R, the green panel 31G, and the blue panel 31B each modulate the illumination light of each corresponding color based on the video signal. The modulated video light of each color utilizes the difference in polarization and wavelength band to Rch-PBS32R and red bonding substrate 35R, Gch-PBS32G and green bonding substrate 35G, or Bch-PBS32B and blue bonding substrate 35B. After being finally synthesized by the synthetic prism 34E, the light is projected onto a projection surface such as a screen (not shown) by the projection optical system 40.

The illumination system 20E generates uniform illumination light based on the light from the light source unit 10 and emits it toward the panel core 30E. The blue light emitted from the light source unit 10 and the yellow light including the red light and the green light are divided by the first fly-eye lens array 21 and the second fly-eye lens array 22 of the illumination system 20E, and then the PS conversion element. By passing through 23, the polarization state is aligned in one direction (S polarization in the example of FIG. 10). The S-polarized blue light is incident on the dichroic mirror 61A or the dichroic mirror 61B via the condenser lens 24. The S-polarized yellow light is incident on the dichroic mirror 61A or the dichroic mirror 61B via the condenser lens 24.

The dichroic mirror 61B reflects the incident blue light. The dichroic mirror 61A transmits the incident blue light. The blue light enters the reflection mirror 62 via the dichroic mirror 61A or the dichroic mirror 61B. The reflection mirror 62 reflects blue light toward Bch-PBS32B in the panel core 30E in an S-polarized state.

Further, the dichroic mirror 61B transmits yellow light including incident red light and green light. Further, the dichroic mirror 61A reflects yellow light including incident red light and green light. The yellow light including the red light and the green light is incident on the reflection mirror 63 via the dichroic mirror 61A or the dichroic mirror 61B. The reflection mirror 63 reflects the incident yellow light including the red light and the green light toward the dichroic mirror 64. The dichroic mirror 64 transmits the incident red light toward Rch-PBS32R in the panel core 30E in an S-polarized state. Further, the dichroic mirror 64 reflects the incident green light toward Gch-PBS32G in the panel core 30E in an S-polarized state.

In the panel core 30E, the Rch-PBS32R and the red bonding substrate 35R are arranged on the optical path (R-ch) of red light. The red bonding substrate 35R is made of a material having a higher thermal conductivity than the synthetic prism 34E and Rch-PBS32R, and bonds the synthetic prism 34E and Rch-PBS32R.

In the panel core 30E, the Gch-PBS32G and the green bonding substrate 35G are arranged on the optical path (G-ch) of the green light. The green bonding substrate 35G is composed of a material having a higher thermal conductivity than the synthetic prism 34E and Gch-PBS32G, and bonds the synthetic prism 34E and Gch-PBS32G.

In the panel core 30E, the Bch-PBS32B and the blue bonding substrate 35B are arranged on the optical path (B-ch) of blue light. The blue bonding substrate 35B is made of a material having a higher thermal conductivity than the synthetic prism 34E and Bch-PBS32B, and bonds the synthetic prism 34E and Bch-PBS32B.

The red bonding substrate 35R, the green bonding substrate 35G, and the blue bonding substrate 35B are arranged so as not to have an optical axis or to affect the polarization direction of the image light of each color. A type of dichroic prism called a cross prism is used for the composite prism 34E. The synthetic prism 34E synthesizes three colors of video light. For Rch-PBS32R, Gch-PBS32G, and Bch-PBS32B, for example, PBH56 is used. For example, S-BSL7 or other optical glass is used for the synthetic prism 34E. Alternatively, the red bonding substrate 35R and the blue bonding substrate 35B are provided with optical characteristics as a half-wave plate (phase difference plate with a phase difference of 90 °) so that the polarization directions of red light and blue light are rotated by 90 °. It may be arranged in any orientation. In this case, the reflection characteristics of red light and blue light in the synthetic prism 34E can be improved.

[6.2 Actions and effects]
According to the projector 1E according to the sixth embodiment, the synthetic prism 34E and the ch-PBS of each color are bonded via the bonding substrate of each color made of a material having high thermal conductivity. Changes in the internal temperature distributions of the synthetic prism 34E and ch-PBS of each color are suppressed, and it is possible to improve the deterioration of the image display state due to the temperature changes of the optical members.

<7. Seventh Embodiment>
Next, the display device according to the seventh embodiment of the present disclosure will be described. In the following, substantially the same parts as the components of the display device according to any one of the first to sixth embodiments are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

[7.1 configuration]
FIG. 11 shows a configuration example of a main part of the projector 1F as a display device according to the seventh embodiment. FIG. 11A shows a state in which the main part of the projector 1F is viewed from the upper surface direction. FIG. 11B shows a state in which the main part of the projector 1F is viewed from the side surface.

The projector 1F according to the seventh embodiment includes a panel core 30F instead of the panel core 30E in the projector 1E according to the sixth embodiment.

The panel core 30F includes a first panel core 30F1, a second panel core 30F2, and a synthetic prism 70. Further, the panel core 30F includes a bonding substrate 71, a bonding substrate 72, and an emission side substrate 73.

The first panel core 30F1 corresponds to a specific example of the "first optical unit" in the technology of the present disclosure. The second panel core 30F2 corresponds to a specific example of the "second optical unit" in the technique of the present disclosure. The synthetic prism 70 corresponds to a specific example of the "second synthetic prism" in the technique of the present disclosure. The bonded substrate 71 corresponds to a specific example of the "fourth substrate" in the technique of the present disclosure. The bonded substrate 72 corresponds to a specific example of the "fifth substrate" in the technique of the present disclosure. The emitting side substrate 73 corresponds to a specific example of the "sixth substrate" in the technique of the present disclosure.

The first panel core 30F1 includes a first red panel 31R1, a first green panel 31G1, a first blue panel 31B1, a first red polarization beam splitter (Rch-PBS) 32R1, and a first green polarization. A beam splitter (Gch-PBS) 32G1 and a first blue polarized beam splitter (Bch-PBS) 32B1 are provided. Further, the first panel core 30F1 includes a first color composite prism 34F1, a first red bonding substrate 35R1, a first green bonding substrate 35G1, and a first blue bonding substrate 35B1.

The second panel core 30F2 includes a second red panel 31R2, a second green panel 31G2, a second blue panel 31B2, a second red polarization beam splitter (Rch-PBS) 32R2, and a second green polarization. It includes a beam splitter (Gch-PBS) 32G2 and a second blue polarized beam splitter (Bch-PBS) 32B2. The second panel core 30F2 includes a second color composite prism 34F2, a second red bonding substrate 35R2, a second green bonding substrate 35G2, and a second blue bonding substrate 35B2.

The first red panel 31R1, the first green panel 31G1, the first blue panel 31B1, the second red panel 31R2, the second green panel 31G2, and the second blue panel 31B2 are the techniques of the present disclosure, respectively. It corresponds to a specific example of a "spatial light modulator". Rch-PBS32R1, Gch-PBS32G1, Bch-PBS32B1, Rch-PBS32R2, Gch-PBS32G2, and Bch-PBS32B2 each correspond to a specific example of a "polarization beam splitter" in the technique of the present disclosure. The first color composite prism 34F1 and the second color composite prism 34F2 correspond to specific examples of the "first composite prism" in the technique of the present disclosure, respectively. The first red bonding substrate 35R1, the first green bonding substrate 35G1, the first blue bonding substrate 35B1, the second red bonding substrate 35R2, the second green bonding substrate 35G2, and the second blue bonding substrate 35B2 are respectively. , Corresponds to a specific example of the "first substrate" in the technique of the present disclosure.

The configurations of the first panel core 30F1 and the second panel core 30F2 are basically the same as those of the panel core 30E in the projector 1E according to the sixth embodiment. The first panel core 30F1 and the second panel core 30F2 are red, green, and blue, respectively, from the light source unit 10 and the lighting system 20E having the same configuration as the light source unit 10 and the lighting system 20E in the projector 1E according to the sixth embodiment. Illumination light of each color is incident.

In the first panel core 30F1, the Rch-PBS32R1 and the first red bonding substrate 35R1 are arranged on the optical path (R-ch) of red light. The first red bonding substrate 35R1 is made of a material having a higher thermal conductivity than the first color synthetic prism 34F1 and Rch-PBS32R1, and bonds the first color synthetic prism 34F1 and Rch-PBS32R1.

In the first panel core 30F1, the Gch-PBS32G1 and the first green bonding substrate 35G1 are arranged on the optical path (G-ch) of green light. The first green bonding substrate 35G1 is composed of a material having a higher thermal conductivity than the first color synthetic prism 34F1 and Gch-PBS32G1, and bonds the first color synthetic prism 34F1 and Gch-PBS32G1.

In the first panel core 30F1, the Bch-PBS32B1 and the first blue bonding substrate 35B1 are arranged on the optical path (B-ch) of blue light. The first blue bonding substrate 35B1 is made of a material having a higher thermal conductivity than the first color synthetic prism 34F1 and Bch-PBS32B1, and bonds the first color synthetic prism 34F1 and Bch-PBS32B1.

In the first panel core 30F1, the first red bonding substrate 35R1, the first green bonding substrate 35G1, and the first blue bonding substrate 35B1 each have no optical axis or affect the polarization direction of the image light of each color. It is arranged so that it does not hold. A type of dichroic prism called a cross prism is used for the first color composite prism 34F1. The first color synthesis prism 34F1 synthesizes three colors of video light. For Rch-PBS32R1, Gch-PBS32G1, and Bch-PBS32B1, for example, PBH56 is used. For example, S-BSL7 or other optical glass is used for the first color synthetic prism 34F1.

In the second panel core 30F2, the Rch-PBS32R2 and the second red bonding substrate 35R2 are arranged on the optical path (R-ch) of red light. The second red bonding substrate 35R2 is made of a material having a higher thermal conductivity than the second color synthetic prism 34F2 and Rch-PBS32R2, and bonds the second color synthetic prism 34F2 and Rch-PBS32R2.

In the second panel core 30F2, the Gch-PBS32G2 and the second green bonding substrate 35G2 are arranged on the optical path (G-ch) of green light. The second green bonding substrate 35G2 is composed of a material having a higher thermal conductivity than the second color synthetic prism 34F2 and Gch-PBS32G2, and bonds the second color synthetic prism 34F2 and Gch-PBS32G2.

In the second panel core 30F2, the Bch-PBS32B2 and the second blue bonding substrate 35B2 are arranged on the optical path (B-ch) of blue light. The second blue bonding substrate 35B2 is made of a material having a higher thermal conductivity than the second color synthetic prism 34F2 and Bch-PBS32B2, and bonds the second color synthetic prism 34F2 and Bch-PBS32B2.

In the second panel core 30F2, the second red bonding substrate 35R2, the second green bonding substrate 35G2, and the second blue bonding substrate 35B2 each have no optical axis or affect the polarization direction of the image light of each color. It is arranged so that it does not hold. A type of dichroic prism called a cross prism is used for the second color composite prism 34F2. The second color synthesis prism 34F2 synthesizes three colors of video light. For Rch-PBS32R2, Gch-PBS32G2, and Bch-PBS32B2, for example, PBH56 is used. For the second color synthetic prism 34F2, for example, S-BSL7 or other optical glass is used.

PBS is used for the synthetic prism 70, and the three-color first image light emitted from the first color synthetic prism 34F1 of the first panel core 30F1 and the second color synthetic prism 34F2 of the second panel core 30F2 are emitted. The second image light of the three colors is further combined. For example, PBH56 is used for the synthetic prism 70.

The bonding substrate 71 is made of a material having a higher thermal conductivity than the first color synthetic prism 34F1 of the first panel core 30F1 and the synthetic prism 70, and joins the first color synthetic prism 34F1 of the first panel core 30F1 and the synthetic prism 70. To do. The bonding substrate 71 is arranged so as not to have an optical axis or to affect the polarization direction of the image light of each color.

The bonding substrate 72 is made of a material having a higher thermal conductivity than the second color synthetic prism 34F2 of the second panel core 30F2 and the synthetic prism 70, and joins the second color synthetic prism 34F2 of the second panel core 30F2 and the synthetic prism 70. To do. The bonding substrate 72 has optical characteristics as a half-wave plate (a retardation plate having a phase difference of 90 °), and is arranged so that the polarization direction of green light is rotated by 90 °.

The synthetic prism 70 has a light emitting surface. The emission side substrate 73 is made of a material having a higher thermal conductivity than that of the synthetic prism 70, and is bonded to the emission surface of the synthetic prism 70.

By giving the emitting side substrate 73 optical characteristics as a quarter wave plate acting on each of the red, blue, and green wavelength bands, the images from the first panel core 30F1 and the second panel core 30F2, respectively. Light may be converted into circularly polarized light in different directions of rotation.

[7.2 Actions and effects]
According to the projector 1F according to the seventh embodiment, for example, glasses provided with an appropriate polarizing filter by emitting an image for the right eye from the first panel core 30F1 and an image for the left eye from the second panel core 30F2. It is possible to provide a 3D image by allowing an observer wearing the spectacles to visually recognize different images for the right eye and the left eye.

According to the projector 1F according to the seventh embodiment, in each of the first panel core 30F1 and the second panel core 30F2, the color synthesis prism and the ch-PBS of each color are formed of each color made of a material having high thermal conductivity. Since the bonding is performed via the bonding substrate of the above, changes in the internal temperature distribution of the color synthesis prism and each color of ch-PBS are suppressed, and the deterioration of the image display state due to the temperature change of those optical members is prevented. It will be possible to improve.

Further, according to the projector 1F according to the seventh embodiment, the color synthesis prisms and the synthesis prisms 70 of the first panel core 30F1 and the second panel core 30F2 are formed of a bonded substrate made of a material having high thermal conductivity. Since the bonding is performed via 71 and 72, changes in the internal temperature distributions of the color synthesis prism and the synthesis prism 70 are suppressed, and the temperature gradient between the color synthesis prism and the synthesis prism 70 is reduced. As a result, focus drift is suppressed.

Further, according to the projector 1F according to the seventh embodiment, the emitting side substrate 73 made of a material having a higher thermal conductivity than that of the synthetic prism 70 is joined to the emitting surface of the synthetic prism 70. Heat is transferred from the central portion having a high temperature to the peripheral portion inside the exit side substrate 73, and the temperature gradient of the synthetic prism 70 is further reduced. As a result, focus drift is further suppressed.

Other configurations, operations and effects may be substantially the same as those of the display device according to the first or sixth embodiment.

<8. Other embodiments>
The technique according to the present disclosure is not limited to the description of each of the above embodiments, and various modifications can be implemented.

For example, the present technology may have the following configuration.
According to the present technology having the following configuration, the first synthetic prism and the polarizing beam splitter are joined via the first substrate made of a material having high thermal conductivity, so that the first synthesis is performed. Changes in the internal temperature distributions of the prism and the polarizing beam splitter are suppressed, and it is possible to improve the deterioration of the image display state due to the temperature changes of the optical members.

(1)
With multiple spatial light modulators
A first synthetic prism that synthesizes a plurality of video lights modulated by the plurality of spatial light modulators, and
At least one polarizing beam splitter that directs the plurality of video lights modulated by the plurality of spatial light modulators to the first synthetic prism.
A display device composed of the first synthetic prism and a material having a higher thermal conductivity than the polarizing beam splitter, and including at least one first substrate for joining the first synthetic prism and the polarizing beam splitter. ..
(2)
The display device according to (1) above, wherein the first substrate has optical characteristics as a retardation plate.
(3)
The display device according to (1) or (2) above, wherein the first substrate has optical characteristics as a wavelength-selective retardation plate.
(4)
The polarization beam splitter has an incident surface of light and
One of the above (1) to (3) further comprising a second substrate made of a material having a higher thermal conductivity than the polarizing beam splitter and bonded to the incident surface of the polarizing beam splitter. The display device described.
(5)
The first synthetic prism has a light emitting surface and has a light emitting surface.
Any of the above (1) to (4), further comprising a third substrate made of a material having a higher thermal conductivity than that of the first synthetic prism and bonded to the exit surface of the first synthetic prism. The display device according to one.
(6)
The above-mentioned one of (1) to (5), wherein a part of the first substrate projects from the junction between the polarization beam splitter and the first synthetic prism and is exposed to the outside. Display device.
(7)
The polarization beam splitter, the first synthetic prism, and a temperature control member provided to thermally act on at least one of the first substrates are further provided (1) to (1) to (1) to (1) to (1) to (1) to (1) to (1) to (1) The display device according to any one of 6).
(8)
At least one of the polarization beam splitter and the first synthetic prism has a temperature coefficient of refractive index dn / dT in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or 586.29 nm.
| Dn / dT | ≤5
The display device according to any one of (1) to (7) above, which is made of a material satisfying the above conditions.
(9)
One of the polarization beam splitter and the first synthetic prism is made of a material having a negative temperature coefficient of refractive index dn / dT in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or 586.29 nm. The display device according to any one of (1) to (8) above, wherein the other is made of a positive material.
(10)
The display device according to any one of (1) to (9) above, wherein a silicone resin is contained in a joint portion between the polarizing beam splitter and the synthetic prism by the first substrate.
(11)
The display device according to any one of (1) to (9) above, wherein the joint portion between the polarizing beam splitter and the synthetic prism by the first substrate does not contain resin.
(12)
The display device according to (4) above, wherein a silicone resin is contained in a joint portion between the second substrate and the polarizing beam splitter.
(13)
The display device according to (4) above, wherein the joint portion between the second substrate and the polarizing beam splitter does not contain resin.
(14)
The display device according to (5) above, wherein a silicone resin is contained in a joint portion between the third substrate and the first synthetic prism.
(15)
The display device according to (5) above, wherein the joint portion between the third substrate and the first synthetic prism does not contain resin.
(16)
First and second optical units, each including the plurality of spatial light modulators, the polarization beam splitter, the first synthetic prism, and the first substrate.
A second image light emitted from the first synthetic prism of the first optical unit and a second image light emitted from the first synthetic prism of the second optical unit are combined. Synthetic prism and
The first synthetic prism of the first optical unit and the second synthetic prism of the first optical unit are made of a material having a higher thermal conductivity than the first synthetic prism and the second synthetic prism. The fourth substrate that joins the prism and
The first synthetic prism of the second optical unit and the second synthetic prism of the second optical unit are made of a material having a higher thermal conductivity than the first synthetic prism and the second synthetic prism. The display device according to (1) above, which includes a fifth substrate for joining a prism.
(17)
The second synthetic prism has a light emitting surface and has a light emitting surface.
The display device according to (16) above, further comprising a third substrate made of a material having a higher thermal conductivity than that of the second synthetic prism and bonded to the exit surface of the second synthetic prism.
(18)
The display device according to any one of (1) to (17) above, further comprising a projection optical system for projecting image light synthesized by the first synthetic prism.

This application claims priority on the basis of Japanese Patent Application No. 2019-136142 filed on July 24, 2019 at the Japan Patent Office, and the entire contents of this application are referred to in this application. Incorporate for application.

One of ordinary skill in the art can conceive of various modifications, combinations, sub-combinations, and changes, depending on design requirements and other factors, which are included in the appended claims and their equivalents. It is understood that it is.

Claims

With multiple spatial light modulators
A first synthetic prism that synthesizes a plurality of video lights modulated by the plurality of spatial light modulators, and
At least one polarizing beam splitter that directs the plurality of video lights modulated by the plurality of spatial light modulators to the first synthetic prism.
A display device composed of the first synthetic prism and a material having a higher thermal conductivity than the polarizing beam splitter, and including at least one first substrate for joining the first synthetic prism and the polarizing beam splitter. ..
The display device according to claim 1, wherein the first substrate has optical characteristics as a retardation plate.
The display device according to claim 1, wherein the first substrate has optical characteristics as a wavelength-selective retardation plate.
The polarization beam splitter has an incident surface of light and
The display device according to claim 1, further comprising a second substrate made of a material having a higher thermal conductivity than the polarizing beam splitter and bonded to the incident surface of the polarizing beam splitter.
The first synthetic prism has a light emitting surface and has a light emitting surface.
The display device according to claim 1, further comprising a third substrate made of a material having a higher thermal conductivity than that of the first synthetic prism and bonded to the exit surface of the first synthetic prism.
The display device according to claim 1, wherein a part of the first substrate protrudes from a junction between the polarizing beam splitter and the first synthetic prism and is exposed to the outside.
The first aspect of claim 1, further comprising the polarization beam splitter, the first synthetic prism, and a temperature control member provided to thermally act on at least one of the first substrates. Display device.
At least one of the polarization beam splitter and the first synthetic prism has a temperature coefficient of refractive index dn / dT in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or 586.29 nm.
| Dn / dT | ≤5
The display device according to claim 1, which is made of a material satisfying the above conditions.
One of the polarization beam splitter and the first synthetic prism is made of a material having a negative temperature coefficient of refractive index dn / dT in the temperature range of 20 ° C. to 40 ° C. at a wavelength of 587.56 nm or 586.29 nm. The display device according to claim 1, wherein the other is made of a positive material.
The display device according to claim 1, wherein a silicone resin is contained in a joint portion between the polarizing beam splitter and the synthetic prism using the first substrate.
The display device according to claim 1, wherein the joint portion between the polarizing beam splitter and the synthetic prism by the first substrate does not contain resin.
The display device according to claim 4, wherein a silicone resin is contained in a joint portion between the second substrate and the polarizing beam splitter.
The display device according to claim 4, wherein the joint portion between the second substrate and the polarizing beam splitter does not contain a resin.
The display device according to claim 5, wherein a silicone resin is contained in the joint portion between the third substrate and the first synthetic prism.
The display device according to claim 5, wherein the joint portion between the third substrate and the first synthetic prism does not contain resin.
First and second optical units, each including the plurality of spatial light modulators, the polarization beam splitter, the first synthetic prism, and the first substrate.
A second image light emitted from the first synthetic prism of the first optical unit and a second image light emitted from the first synthetic prism of the second optical unit are combined. Synthetic prism and
The first synthetic prism of the first optical unit and the second synthetic prism of the first optical unit are made of a material having a higher thermal conductivity than the first synthetic prism and the second synthetic prism. The fourth substrate that joins the prism and
The first synthetic prism of the second optical unit and the second synthetic prism of the second optical unit are made of a material having a higher thermal conductivity than the first synthetic prism and the second synthetic prism. The display device according to claim 1, further comprising a fifth substrate for joining the prism.
The second synthetic prism has a light emitting surface and has a light emitting surface.
The display device according to claim 16, further comprising a sixth substrate made of a material having a higher thermal conductivity than that of the second synthetic prism and bonded to the exit surface of the second synthetic prism.
The display device according to claim 1, further comprising a projection optical system for projecting image light synthesized by the first synthetic prism.