Light guide elements, optical modules, and projectors

Abstract

The present invention provides a light guide element, optical module, and projector that suppress the reduction in adhesive strength of the adhesive. [Solution] The light guide element of the present invention comprises a plurality of plate materials that define a light guide path that guides light incident from the incident end and emits it from the exit end, and an adhesive that adheres the plurality of plate materials to each other outside the light guide path, wherein the plurality of plate materials include a first member having a first reflective surface and a second member having a second reflective surface, and the contact area of ​​the adhesive with respect to the first member and the second member is larger from the middle to the exit end than from the middle to the incident end of the light guide path.

Description

【Technical Field】 【0001】 The present invention relates to a light guide element, an optical module, and a projector. 【Background Art】 【0002】 Conventionally, a projector including a light source that emits light, a light modulation device that modulates the light emitted from the light source according to image information to generate image light, and a projection optical system that enlarges and projects the image light emitted from the light modulation device onto a projection surface such as a screen is known. 【0003】 In Patent Document 1 below, an LED light source that emits light, a block-shaped light guide element that emits the light emitted from the LED light source from the emission end so that the brightness is uniform, a condenser lens that forms an image of the light source image of the light emitted from the light guide element at the entrance pupil position of the projection lens, a light modulation element that generates image light, and a projection lens are disclosed. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2000-180962 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, in the above projector, it is difficult to completely take in the light emitted from the LED light source into the light guide element, and the light leaks out as leakage light from the gap between the light source and the light guide element to the outside of the light guide element. For example, in the above projector, instead of the block-shaped light guide element, it is also conceivable to use a rectangular reflector in which four mirrors are bonded together with an adhesive. When such a rectangular reflector is adopted in a high-brightness projector, the amount of leakage light incident on the adhesive increases, which may impair the adhesive reliability of the adhesive. [Means for solving the problem] 【0006】 To solve the above problems, a light guide element according to one aspect of the present invention comprises a plurality of plate materials that define a light guide path that guides light incident from an incident end and emits it from an exit end, and an adhesive that adheres the plurality of plate materials to each other outside the light guide path, wherein the plurality of plate materials include a first member having a first reflective surface and a second member having a second reflective surface, and the contact area of ​​the adhesive with respect to the first member and the second member is larger from the middle part of the light guide path to the exit end than from the middle part to the incident end. 【0007】 An optical module according to one aspect of the present invention comprises: a light guide element according to one aspect of the present invention; a first light source that emits first light in a first wavelength band toward the incident end of the light guide path in the light guide element; a first parallelizing element that parallelizes the first light emitted from the exit end of the light guide path; and a first optical modulation device that modulates the first light emitted from the first parallelizing element based on image information. 【0008】 A projector according to one aspect of the present invention includes: a first image forming module having: a first light guide element made of a light guide element according to one aspect of the present invention; a first light source that emits first light in a first wavelength band toward the first light guide element; a first parallelizing element that parallelizes the first light emitted from the first light guide element; and a first light modulation device that modulates the first light emitted from the first parallelizing element based on image information; a second light source made of a light guide element according to one aspect of the present invention; a second light source that emits second light in a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element that parallelizes the second light emitted from the second light guide element; and a second light modulation device that modulates the second light emitted from the second parallelizing element based on image information. A projector comprising: a second image forming module having a modulation device; a third light guide element comprising a light guide element according to one aspect of the present invention; a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band toward the third light guide element; a third parallelizing element that parallelizes the third light emitted from the third light guide element; a third light modulation device that modulates the third light emitted from the third parallelizing element based on image information; a photosynthesis element that combines light emitted from the first image forming module, light emitted from the second image forming module, and light emitted from the third image forming module; and a projection optical system that projects the light emitted from the photosynthesis element. 【0009】 A projector according to one aspect of the present invention comprises a first image forming module according to one aspect of the present invention, a second image forming module, a third image forming module, a photosynthesis element, and a projection optical system, wherein the second image forming module includes a second light source that emits second light in a second wavelength band different from the first wavelength band, a light uniformizing element that receives the second light emitted from the second light source and uniformizes the in-plane illuminance of the second light, a second parallelizing element that parallelizes the second light emitted from the light uniformizing element, and a projection optical system that projects the second light emitted from the second parallelizing element into an image The third image forming module includes a second optical modulator that modulates based on information, and the third image forming module includes a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band, and a third optical modulator that modulates the third light emitted from the third light source based on image information, the photosynthetic element combines and emits light emitted from the first image forming module, light emitted from the second image forming module and light emitted from the third image forming module, and the projection optical system projects the light emitted from the photosynthetic element. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a plan view showing the schematic configuration of the projector according to the embodiment. [Figure 2] This is a perspective view of a light guide element. [Figure 3] This is a plan view showing the peripheral configuration of the light guide element. [Figure 4] This is a cross-sectional view along line IV in Figure 3. [Figure 5] This is a schematic diagram to explain the behavior of stray light. [Modes for carrying out the invention] 【0011】 Embodiments of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a liquid crystal projector that uses a liquid crystal panel as an optical modulation device. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see. 【0012】 Figure 1 is a plan view showing the schematic configuration of the projector according to the embodiment. As shown in Figure 1, the projector 301 is an image display device equipped with three liquid crystal panels as an optical modulation device, and is a so-called three-panel projector. The projector 301 comprises a first image forming module 100B, a second image forming module 100G, a third image forming module 100R, a photosynthesis element 200, and a projection optical system 250. 【0013】 The first image forming module 100B includes a blue light emitter 101 and a blue light modulator (first light modulator) 104. The second image forming module 100G includes a green light emitter 102 and a green light modulator (second light modulator) 105. The third image forming module 100R includes a red light emitter 103 and a red light modulator (third light modulator) 106. 【0014】 First, the first image forming module 100B will be described. The blue light emission unit 101 of the first image forming module 100B emits blue light LB. In the following description, the direction parallel to the optical axis of the blue light LB emitted from the blue light emission unit 101 will be referred to as the D1 direction. One side in the D1 direction will be referred to as the -D1 side, and the side opposite to the -D1 side in the D1 direction will be referred to as the +D1 side. The direction perpendicular to the D1 direction in the plane containing the optical axis of the blue light LB will be referred to as the D2 direction. One side in the D2 direction will be referred to as the -D2 side, and the side opposite to the -D2 side in the D2 direction will be referred to as the +D2 side. The direction perpendicular to both the D1 and D2 directions will be referred to as the D3 direction. The blue light LB emitted from the blue light emission unit 101 travels along the D1 direction towards the +D1 side. 【0015】 The blue light emitting section 101 includes a first light source 401, a first light guide element 41, and a first parallelizing element 161. The first light-emitting element 121 of the first light source 401 is supported on a first substrate 111. The first substrate 111 is a plate parallel to a plane including the D2 direction and the D3 direction. 【0016】 The first light-emitting element 121 is provided on the plate surface on the +D1 side of the first substrate 111. The light-emitting surface of the first light-emitting element 121 is the surface on the +D1 side opposite to the surface provided on the first substrate 111. The first light-emitting element 121 emits blue light LB in the blue wavelength band in the visible wavelength band. The blue wavelength band corresponds to the first wavelength band. The blue light LB corresponds to the first light. The blue light LB is emitted toward the +D1 side around an axis parallel to the D1 direction passing through the center of the light-emitting surface of the first light-emitting element 121. The blue wavelength band is, for example, a wavelength band of 420 nm to 500 nm. Since the blue wavelength band has the shortest wavelength among the color lights used in a three-panel projector, it has high energy. 【0017】 The first light-emitting element 121 is composed of, for example, an LED that emits blue light LB. Note that the first light-emitting element 121 may be composed of one LED or may be composed of the entire plurality of LEDs. When the first light-emitting element 121 is composed of a plurality of LEDs, the plurality of LEDs are arranged in the region occupied by the first light-emitting element 121 in the plane including the D2 direction and the D3 direction. 【0018】 The first light guide element 41 is provided on the optical path of the blue light LB emitted from the first light source 401, and is arranged on the +D1 side of the first light-emitting element 121 of the first light source 401 and at a position overlapping the first light-emitting element 121 in the D2 direction and the D3 direction. Details of the first light guide element 41 will be described later. 【0019】 The first collimating element 161 is provided on the optical path of the blue light LB emitted from the first light guide element 41. The first collimating element 161 collimates the blue light LB emitted from the first light guide element 41 along the D1 direction. 【0020】 The blue light modulation device 104 includes a first incident-side polarizing element 171, a first light modulation element 181, and a first emission-side polarizing element 175. The blue light modulation device 104 is provided on the optical path of the blue light LB emitted from the first collimating element 161. 【0021】 The first incident-side polarizing element 171 is arranged on the +D1 side of the first collimating element 161. The first incident-side polarizing element 171 emits a predetermined polarization of the blue light LB emitted from the first collimating element 161 to the +D1 side along the D1 direction. The first incident-side polarizing element 171 is, for example, a reflective polarizing plate or an absorptive polarizing plate. 【0022】 The first optical modulation element 181 is arranged on the +D1 side of the first incident-side polarizing element 171. The first optical modulation element 181 modulates the blue light LB emitted from the first incident-side polarizing element 171. The first optical modulation element 181 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the first optical modulation element 181 generates blue image light IB by modulating light based on blue image information. The first optical modulation element 181 emits the generated image light IB to the +D1 side along the D1 direction. 【0023】 The first emission-side polarizing element 175 is arranged on the +D1 side of the first optical modulation element 181. The first emission-side polarizing element 175 emits a predetermined polarization of the image light IB emitted from the first optical modulation element 181 to the +D1 side along the D1 direction. The first emission-side polarizing element 175 is, for example, a reflective polarizing plate or an absorptive polarizing plate. 【0024】 Next, the configuration of the first light guide element 41 will be described. FIG. 2 is a perspective view of the first light guide element 41. As shown in FIG. 2, the first light guide element 41 defines a light guide path for guiding the blue light LB emitted from the first light emitting element 121, and propagates the blue light LB to the first optical modulation element 181. The first light guide element 41 is composed of a plurality of plate members 10 made of a transparent material. The plurality of plate members 10 includes a first member 11, a second member 12, a third member 13, and a fourth member 14. 【0025】 The first member 11 and the third member 13 are a pair of rectangular plate members. The first member 11 has a first reflection surface 11a on one plane. The third member 13 has a third reflection surface 13a on one plane. The first member 11 and the third member 13 are plate members of the same shape. The second member 12 and the fourth member 14 are a pair of trapezoidal plate materials. The second member 12 has a second reflective surface 12a on one of its planes. The fourth member 14 has a fourth reflective surface 14a on one of its planes. The second member 12 and the fourth member 14 are plate materials of the same shape. Hereafter, when the first reflective surface 11a, the second reflective surface 12a, the third reflective surface 13a, and the fourth reflective surface 14a are not specifically distinguished, they may be collectively referred to as the reflective surface 10a. The reflective surface 10a constitutes a light guide path 41L that guides blue light LB to the inside of the first light guide element 41. Thus, the first light guide element 41 is easy to manufacture by using four plates. Furthermore, since the first light guide element 41 is constructed using rectangular plates, the number of times the plates need to be processed can be reduced. In addition, because the plates have a simple shape, assembly is easy. 【0026】 The first reflective surface 11a of the first member 11 and the third reflective surface 13a of the third member 13 are positioned opposite each other. The second reflective surface 12a of the second member 12 and the fourth reflective surface 14a of the fourth member 14 are positioned opposite each other. The second member 12 and the fourth member 14 are positioned such that their upper bases are on the -D1 side and their lower bases are on the +D1 side. One side of the trapezoidal second member 12 and fourth member 14, which forms the slanted edge, is connected to the first reflective surface 11a of the first member 11. The other side of the trapezoidal second member 12 and fourth member 14, which forms the slanted edge, is connected to the third reflective surface 13a of the third member 13. The multiple plate materials 10 are bonded together using an adhesive 50, which will be described later. As a result, the shape of the first light guide element 41 is formed by the multiple plate materials 10. 【0027】 The first member 11 has a first incident end face 11e at the -D1 side end. The second member 12 has a second incident end face 12e at the -D1 side end. The third member 13 has a third incident end face 13e at the -D1 side end. The fourth member 14 has a fourth incident end face 14e at the -D1 side end. A portion of the first incident end face 11e, the second incident end face 12e, a portion of the third incident end face 13e, and the fourth incident end face 14e form an incident opening 45. The incident opening 45 forms the incident end 41a of the light guide path 41L. 【0028】 The first member 11 has a first injection end face 11f at its +D1 side end. The second member 12 has a second injection end face 12f at its +D1 side end. The third member 13 has a third injection end face 13f at its +D1 side end. The fourth member 14 has a fourth injection end face 14f at its +D1 side end. The first injection end face 11f, the second injection end face 12f, the third injection end face 13f, and the fourth injection end face 14f form an injection opening 46. The injection opening 46 forms the injection end 41b of the light guide path 41L. 【0029】 The entrance aperture 45 extends parallel to the planes including the D2 and D3 directions. The shape of the entrance aperture 45 when viewed from the D1 direction is the same as the shape of the light-emitting surface of the first light-emitting element 121 when viewed from the same direction, and is rectangular. The size of the entrance aperture 45 may be the same as the size of the light-emitting surface of the first light-emitting element 121, but preferably it is moderately larger than the size of the light-emitting surface of the first light-emitting element 121. 【0030】 The ejection aperture 46 extends parallel to the planes including the D2 and D3 directions. The ejection aperture 46 is larger than the entrance aperture 45. When viewed from the D1 direction, the shape of the ejection aperture 46 is rectangular. The size of the ejection end 41b is equivalent to the size of the first optical modulation element 181. This configuration allows for an increase in the luminous flux width during the propagation of the blue light LB incident from the entrance aperture 45 within the optical guide path. This enables the generation of blue light LB with a uniform illuminance distribution that efficiently illuminates the entire first optical modulation element 181. 【0031】 Figure 3 is a plan view showing the peripheral configuration of the light guide element. As shown in Figure 3, the light guide path 41L of the first light guide element 41 has an incident end 41a and an exit end 41b. The incident end 41a is located on the -D1 side in the D1 direction. The exit end 41b is located on the +D1 side in the D1 direction. 【0032】 Here, the first incident end face 11e and the third incident end face 13e are parallel to the plane including the D2 and D3 directions. When ordinary plate materials are simply bonded together, the corners of the first incident end face 11e and the third incident end face 13e of the first member 11 and the third member 13 protrude toward the -D1 side, as shown by the dotted line in Figure 3. In this embodiment, the corners of the first incident end face 11e and the third incident end face 13e are cut off so that they are parallel to the plane including the D2 and D3 directions. Similarly, the second incident end face 12e and the fourth incident end face 14e are also parallel to the plane including the D2 and D3 directions. In this embodiment, the "plane including the D2 and D3 directions" corresponds to the "plane perpendicular to the optical axis of the optical guide" in the claims. This configuration allows for a smaller gap in the D1 direction between the incident aperture 45 and the first light source 401. As a result, the incident aperture 45 and the first light source 401 can be positioned closer together in the D1 direction. Therefore, the amount of stray light LL generated between the first light source 401 and the incident aperture 45 of the first light guide element 41 can be suppressed. 【0033】 Furthermore, in this embodiment, the first injection end face 11f and the third injection end face 13f are parallel to the plane including the D2 and D3 directions. Similarly, the second injection end face 12f and the fourth injection end face 14f are parallel to the plane including the D2 and D3 directions. The corners of the first incident end face 11e and the third incident end face 13e may be cut off so as to be parallel to the plane including the D2 and D3 directions. This configuration allows for a smaller gap between the ejection aperture 46 and the first light modulation element 181. As a result, the ejection aperture 46 and the first light modulation element 181 can be positioned closer together. Therefore, the amount of stray light LL generated between the ejection aperture 46 of the first light guide element 41 and the first light modulation element 181 can be suppressed. 【0034】 The blue light LB emitted from the first light source 401 enters the light guide path 41L of the first light guide element 41 from the incident end 41a. In the first light guide element 41, the space enclosed by the incident aperture 45, the exit aperture 46, and the reflective surface 10a becomes the light guide path 41L through which the blue light LB propagates. In this way, the blue light LB incident on the first light guide element 41 propagates through the light guide path 41L from the -D1 side to the +D1 side. 【0035】 A portion of the blue light LB incident on the first light guide element 41 propagates directly from the incident end 41a to the exit end 41b along a direction that forms an angle smaller than the inclination of the trapezoidal hypotenuse in the second member 12 and the fourth member 14, without ever being incident on the reflective surface 10a. The remaining portion of the blue light LB incident on the first light guide element 41 forms an angle greater than the aforementioned angle, is incident on the reflective surface 10a one or more times from the incident end 41a, is reflected by the reflective surface 10a, and then reaches the exit end 41b. The path of the blue light LB within the region enclosed by the incident end 41a, the exit end 41b, and the reflective surface 10a differs depending on the angle of incidence to the incident end 41a, and extends to multiple paths with different numbers of reflections at the reflective surface 10a. As a result, the illuminance distribution of the blue light LB propagating in the region enclosed by the incident end 41a, the exit end 41b, and the reflective surface 10a is made uniform in a plane including the D2 and D3 directions. In other words, the first light guide element 41 makes the illuminance distribution of the incident blue light LB uniform in a plane including the D2 and D3 directions. The blue light LB with a uniform illuminance distribution is emitted from the exit end 41b towards the +D1 side. 【0036】 Next, the adhesive 50 for bonding the multiple plate materials 10 will be described. The adhesive 50 bonds each of the multiple plate materials 10 outside the light guide path, forming a first light guide element 41 having a light guide path 41L. The adhesive 50 is provided along a part of the trapezoidal hypotenuse in the second member 12 and the fourth member 14. Overall, the adhesive 50 is provided on the side of the ejection end 41b rather than the intermediate part M in the longitudinal direction (D1 direction) of the light guide path 41L. Here, the intermediate part M of the light guide path 41L means the part located equidistant from the incident end 41a and the ejection end 41b in the D1 direction. In this embodiment, the adhesive 50 is provided from the inlet end 41a to the injection end 41b, extending to a position approximately 3 / 4 of the way. Alternatively, a portion of the adhesive 50 may be provided closer to the inlet end 41a than to the intermediate portion M. The contact area of ​​the adhesive 50 with the multiple plate materials 10 is larger from the intermediate part M to the ejection end 41b than from the intermediate part M to the incident end 41a of the light guide path. More specifically, this will be explained using Figure 4. 【0037】 Figure 4 is a cross-sectional view along line IV in Figure 3. In Figure 4, for clarity, we focus only on how the adhesive 50 adheres to the first member 11 and the second member 12. As shown in Figures 3 and 4, the adhesive 50 is located outside the light guide path defined by the first light guide element 41. 【0038】 The first member 11 and the second member 12 are bonded together such that one side of the second member 12, which is the slanted edge portion, abuts against a portion of the first reflective surface 11a of the first member 11. The adhesive 50 adheres to the outside of the light guide path 41L on the first reflective surface 11a, and to the outer surface 11b of the second member 12 that is opposite to the second reflective surface 12a. As a result, the contact area of ​​the adhesive 50 with the first member 11 and the second member 12 is larger from the intermediate part M to the ejection end 41b of the light guide path 41L than from the intermediate part M to the incident end 41a. In this way, the first member 11 and the second member 12 are bonded together via the adhesive 50. Similarly, the second member 12 and the third member 13, the third member 13 and the fourth member 14, and the fourth member and the first member 11 are bonded together via the adhesive 50. 【0039】 Furthermore, the adhesive 50 does not necessarily have to be integrally formed along a portion of the trapezoidal hypotenuse of the second member 12 and the fourth member 14, but may be provided in a manner that is interrupted in multiple sections. In this embodiment, the contact area includes not only cases where there is continuous contact, but also the total area of ​​contacts that are intermittently in contact. 【0040】 Any type of adhesive 50 may be used, including UV-curing type, natural curing type, and heat-curing type. The adhesive 50 only needs to be able to bond multiple plate materials 10 together to form the shape of the first light guide element 41, and can be changed as appropriate. 【0041】 In the first light guide element 41 configured in this way, even when the entrance aperture 45 and the first light source 401 are brought close together, some of the blue light LB may leak out of the light guide path 41L, resulting in leaked light LL. Leaked light LL is generated between the first light source 401 and the entrance aperture 45 of the first light guide element 41, and leaks out of the light guide path 41L. 【0042】 Here, we will explain the behavior of leaked light LL. Figure 5 is a schematic diagram illustrating the behavior of leaked light LL. As shown in Figure 5, leaked light LL is light emitted from the first light source 401 along a direction that forms an angle greater than the trapezoidal taper angle in the second member 12 and the fourth member 14. Leaked light LL contains various angular components, but leaked light LL emitted along a direction that forms an angle slightly greater than the trapezoidal taper angle in the second member 12 and the fourth member 14 is more likely to be incident on the side of the incident end 41a of the first light guide element 41. On the other hand, in order for the leaked light LL to reach the side surface of the first light guide element 41 on the exit end 41b side, the leaked light LL emitted in a direction that forms an angle equivalent to the trapezoidal taper angle of the second member 12 and the fourth member 14 must travel along the outer surface of the first light guide element 41 from the incident end 41a side to the exit end 41b side. In this way, the amount of light LL that reaches the exit end 41b side of the leaked light LL is sufficiently less than the amount of light incident on the incident end 41a side. Therefore, if the adhesive 50 is provided on the incident end 41a side, the amount of stray light LL irradiated increases, making the adhesive 50 more prone to deterioration. 【0043】 In contrast, in the first light guide element 41 of this embodiment, the adhesive 50 is provided on the ejection end 41b side rather than the incident end 41a side. Therefore, the leaked light LL that leaks out from the incident aperture 45 of the first light guide element 41 is less likely to hit the adhesive 50, and the deterioration of the adhesive 50 can be suppressed. Thus, the decrease in the adhesive strength of the adhesive 50 used to bond multiple plate materials 10 can be suppressed. 【0044】 As described above, the first light guide element 41 of this embodiment comprises a plurality of plate materials 10 that have an incident end 41a and an exit end 41b and demarcate a light guide path for guiding light, and an adhesive 50 that adheres the plurality of plate materials 10 outside the light guide path 41L. The plurality of plate materials 10 include a first member 11 having a first reflective surface 11a and a second member 12 having a second reflective surface 12a. The contact area of ​​the adhesive 50 with the first member 11 and the second member 12 is larger from the intermediate part M to the exit end 41b than from the intermediate part M to the incident end 41a. 【0045】 In the first light guide element 41 of this embodiment, since the adhesive 50 is provided on the ejection end 41b side rather than the input end 41a side, leaked light LL that leaks to the outside from the input aperture 45 of the first light guide element 41 is less likely to hit the adhesive 50, and deterioration of the adhesive 50 can be suppressed. Therefore, a decrease in the adhesive strength of the adhesive 50 used to bond multiple plate materials 10 can be suppressed. 【0046】 Furthermore, compared to the case where all of the boards 10 are trapezoidal, the bonding surface between the adhesive 50 and the boards 10 can be made wider, making it easier to apply the adhesive 50 and facilitating assembly. 【0047】 As described above, the first image forming module 100B of this embodiment includes a first light guide element 41, a first light source 401, a first parallelizing element 161, and a first light modulation device 104. 【0048】 According to the first image forming module 100B of this embodiment, since it is equipped with a first light guide element 41, it is possible to provide a highly reliable optical module that suppresses a decrease in the adhesive strength of the adhesive 50 used to bond the multiple plate materials 10. 【0049】 Next, the second image forming module 100G will be described. The green light emission unit 102 of the second image forming module 100G is positioned on the +D1 and -D2 side of the blue light emission unit 101, and is located in a region that overlaps with the blue light emission unit 101 in the D3 direction. The green light emission unit 102 emits green light LG. The green light LG emitted from the green light emission unit 102 travels along the D2 direction towards the +D2 side. 【0050】 The green light emitting section 102 includes a second light source 402, a second light guide element 42, and a second parallelizing element 162. The second light-emitting element 122 of the second light source 402 is supported on a second substrate 112. The second substrate 112 is a plate parallel to a plane including the D2 direction and the D3 direction. 【0051】 The second light-emitting element 122 is provided on the +D1 side surface of the second substrate 112. The light-emitting surface of the second light-emitting element 122 is the +D1 side surface opposite to the surface provided on the second substrate 112. The second light-emitting element 122 emits green light LG in the green wavelength band of the visible wavelength band. The green wavelength band corresponds to the second wavelength band. The green light LG corresponds to the second light. The green light LG is emitted towards the +D2 side, centered on an axis parallel to the D2 direction passing through the center of the light-emitting surface of the second light-emitting element 122. The green wavelength band is, for example, the wavelength band of 500nm to 600nm. Also, since the green wavelength band is easily perceived by the human eye, a large amount of light is required when projecting it onto a screen SCR. The second light-emitting element 122, like the first light-emitting element 121, is composed of, for example, an LED that emits green light LG. 【0052】 The second light guide element 42 is located on the optical path of the green light LG emitted from the second light source 402. The configuration of the second light guide element 42 is the same as that of the first light guide element 41, and it has an optical path for guiding the green light LG. 【0053】 The second parallelizing element 162, like the first parallelizing element 161, parallelizes the green light LG emitted from the second light guide element 42 along the D2 direction. 【0054】 The green light modulator 105 includes a second incident polarizing element 172, a second light modulator 182, and a second exit polarizing element 176. The green light modulator 105 is positioned on the optical path of the green light LG emitted from the second parallelizing element 162. 【0055】 The second incident polarizing element 172, like the first incident polarizing element 171, emits a predetermined polarization of the green light LG emitted from the second parallelizing element 162 along the D2 direction towards the +D2 side. 【0056】 The second optical modulator 182 modulates the green light LG emitted from the second incident polarizing element 172, similar to the first optical modulator 181. The second optical modulator 182 generates green image light IG based on the green image information. The second optical modulator 182 emits the image light IG along the D2 direction towards the +D2 side. 【0057】 The second emission polarizing element 176, like the first emission polarizing element 175, emits a predetermined polarization of the image light IG emitted from the second optical modulation element 182 along the D2 direction towards the +D2 side. 【0058】 As described above, the second image forming module 100G of this embodiment includes a second light guide element 42, a second light source 402, a second parallelizing element 162, and a second light modulation device 105. 【0059】 According to the second image forming module 100G of this embodiment, the configuration of the second light guide element 42 is the same as that of the first light guide element 41. Therefore, the second image forming module 100G, like the first image forming module 100B, can provide a highly reliable optical module that suppresses a decrease in the adhesive strength of the adhesive 50 that bonds the multiple plate materials 10. 【0060】 Next, the third image forming module 100R will be described. The red light emission unit 103 of the third image forming module 100R is positioned on the +D1 side of the green light emission unit 102 and is located in a region that overlaps with the blue light emission unit 101 in the D2 and D3 directions. The red light emission unit 103 emits red light LR. The red light LR emitted from the red light emission unit 103 travels along the D1 direction toward the -D1 side. 【0061】 The red light emitting section 103 includes a third light source 403, a third light guide element 43, and a third parallelizing element 163. The third light-emitting element 123 of the third light source 403 is supported on a third substrate 113. The third substrate 113 is a plate parallel to a plane including the D2 direction and the D3 direction. 【0062】 The third light-emitting element 123 is provided on the +D1 side surface of the third substrate 113. The light-emitting surface of the third light-emitting element 123 is the +D1 side surface opposite to the surface provided on the third substrate 113. The third light-emitting element 123 emits red light LR in the red wavelength band of the visible wavelength band. The red wavelength band corresponds to the third wavelength band. The red light LR corresponds to the third light. The red light LR is emitted towards the -D1 side, centered on an axis parallel to the D1 direction passing through the center of the light-emitting surface of the third light-emitting element 123. The red wavelength band is, for example, the wavelength band of 610 nm to 700 nm. The third light-emitting element 123, like the first light-emitting element 121 and the second light-emitting element 122, is composed of, for example, an LED that emits red light LR. 【0063】 The third light guide element 43 is located on the optical path of the red light LR emitted from the third light source 403. The configuration of the third light guide element 43 is the same as that of the first light guide element 41, and it has an optical path for guiding the green light LG. 【0064】 The third parallelizing element 163, like the first parallelizing element 161 and the second parallelizing element 162, parallelizes the red light LR emitted from the third light guide element 43 along the D1 direction. 【0065】 The red light modulator 106 includes a third incident polarizing element 173, a third light modulator 183, and a third exit polarizing element 177. The red light modulator 106 is positioned on the optical path of the red light LR emitted from the third parallelizing element 163. 【0066】 The third incident polarizing element 173, like the first incident polarizing element 171 and the second incident polarizing element 172, emits a predetermined polarization of the red light LR emitted from the third parallelizing element 163 along the D1 direction toward the -D1 side. 【0067】 The third optical modulator 183 modulates the red light LR emitted from the third incident polarizing element 173, similar to the first optical modulator 181 and the second optical modulator 182. The third optical modulator 183 generates red image light IR. The third optical modulator 183 emits the image light IR along the D1 direction toward the -D1 side. 【0068】 The third emission polarizing element 177, like the first emission polarizing element 175 and the second emission polarizing element 176, emits a predetermined polarization of the image light IR emitted from the third optical modulation element 183 along the D1 direction toward the -D1 side. 【0069】 The photosynthetic element 200 is positioned in the region where the optical paths of the blue image light IB, the green image light IG, and the red image light IR intersect. The photosynthetic element 200 synthesizes the image lights IB, IG, and IR emitted from the first emission polarizing element 175, the second emission polarizing element 176, and the third emission polarizing element 177, and emits the resulting image light IM along the D2 direction towards the +D2 side. 【0070】 The projection optical system 250 is positioned on the optical path of the image light IM emitted from the photosynthesis element 200. The projection optical system 250 projects onto the screen SCR and displays the images input to the first optical modulator 181, second optical modulator 182, and third optical modulator 183 on the screen SCR. 【0071】 Thus, the third image forming module 100R of this embodiment includes a third light guide element 43, a third light source 403, a third parallelizing element 163, and a third light modulation device 106. 【0072】 According to the third image forming module 100R of this embodiment, the configuration of the third light guide element 43 is the same as that of the first light guide element 41. Therefore, the third image forming module 100R, like the first image forming module 100B, can provide a highly reliable optical module that suppresses a decrease in the adhesive strength of the adhesive 50 that bonds the multiple plate materials 10. 【0073】 As described above, the projector of this embodiment comprises a first image forming module 100B having a first light guide element 41, a first light source 401, a first parallelizing element 161, and a first light modulator 104; a second image forming module 100G having a second light guide element 42, a second light source 402, a second parallelizing element 162, and a second light modulator 105; a third image forming module 100R having a third light guide element 43, a third light source 403, a third parallelizing element 163, and a third light modulator 106; a photosynthesis element; and a projection optical system. 【0074】 According to the projector 301 of this embodiment, since each image forming module 100B, 100G, and 100R corresponding to three colors is equipped with the light guide elements 41, 42, and 43, a highly reliable projector can be provided that suppresses the decrease in adhesive strength due to irradiation with light of each color of the adhesive bonding the multiple plate materials 10 constituting each light guide element 41, 42, and 43. 【0075】 In the above embodiment of the projector 301, an example was given in which the first image forming module 100B, the second image forming module 100G, and the third image forming module 100R are each composed of the optical module of the present invention, but the projector of the present invention is not limited to this. For example, the optical module of the present invention may be applied to only one-color image forming module among the first image forming module 100B, the second image forming module 100G, and the third image forming module 100R, or it may be applied to two-color image forming modules. When the optical module of the present invention is applied to only one-color image forming module, it is preferable to use a projector in which the optical module corresponding to blue light LB or green light LG is the first image forming module. For example, in the case of a projector equipped only with the first image forming module 100B described above, the second image forming module may include a second light source 402 that emits green light LG, a light uniformizing element that replaces the light guide element of the present invention for uniformizing the in-plane illuminance of the green light LG, a second parallelizing element 162 that parallelizes the green light LG emitted from the light uniformizing element, and a green light modulator 105. The third image forming module may include a third light source 403 that emits red light LR and a red light modulator 106. The third image forming module may also include a third parallelizing element 163 that parallelizes the red light LR and a light uniformizing element that uniformizes the in-plane illuminance of the red light LR, similar to the second image forming module. Furthermore, when applying the optical module of the present invention to a two-color image forming module, it is preferable to apply it to an image forming module for blue light LB and green light LG. For the reasons stated above, blue light LB has the shortest wavelength and therefore the highest energy among RGB, making it prone to degradation of adhesive strength. Green light LG is also most sensitive to human vision, requiring a greater amount of light compared to other colors to maintain the desired white balance, thus also prone to degradation of adhesive strength. Thus, by applying the present invention to a light guide element that guides blue light LB or green light LG, the decrease in adhesive strength of the adhesive 50 can be suppressed more effectively. 【0076】 In this embodiment, the case in which the multiple plate materials 10 are composed of four plate materials has been described, but they may also be composed of two plate materials. More specifically, the first member 11 and the second member 12 may be formed integrally. Similarly, the third member 13 and the fourth member 14 may be formed integrally. 【0077】 A summary of this disclosure is provided below. 【0078】 (Note 1) Multiple plate materials that define the light guide path, which guides light incident from the incident end and emits it from the exit end, An adhesive for bonding the plurality of plate materials outside the light guide path, Equipped with, The plurality of plate materials include a first member having a first reflective surface and a second member having a second reflective surface. The contact area of ​​the adhesive with respect to the first member and the second member is greater from the intermediate portion to the injection end of the light guide than from the intermediate portion to the input end. Light guide element. 【0079】 In some cases, some light leaks outside the light guide path, resulting in stray light. Stray light is light emitted beyond the outer surfaces of the multiple plate materials. Stray light contains various angular components, but stray light emitted along a direction away from the outer surfaces of the multiple plate materials is more likely to be incident on the side of the light guide element on the incident end side. On the other hand, in order for stray light to reach the side of the light guide element on the exit end side, it needs to travel along the outer surfaces of the multiple plate materials. Thus, the amount of stray light that reaches the exit end side is significantly less than the amount of light incident on the incident end side. Therefore, if the adhesive is placed on the incident end side, the amount of stray light exposure increases, which can easily lead to deterioration of the adhesive. In contrast, with this configuration of the light guide element, since the adhesive is placed on the exit end side rather than the incident end side, stray light leaking to the outside from the incident aperture of the light guide element is less likely to hit the adhesive, thus suppressing deterioration of the adhesive. Therefore, it is possible to suppress a decrease in the adhesive strength of the adhesive bonding multiple plate materials. 【0080】 (Note 2) The plurality of plate materials further include a third member having a third reflective surface and a fourth member having a fourth reflective surface, The light guide path is configured such that the first reflective surface of the first member and the third reflective surface of the third member face each other, and the second reflective surface of the second member and the fourth reflective surface of the fourth member face each other. The light guide element described in Appendix 1. 【0081】 According to this configuration, the light guide element is said to be easy to manufacture by using four plates. 【0082】 (Note 3) The first member and the third member are composed of a pair of rectangular plates. The second and fourth members are composed of a pair of trapezoidal plates, The light guide path includes a rectangular entrance aperture located at the entrance end and a rectangular exit aperture located at the exit end, The injection opening is larger than the inlet opening. The light guide element described in Appendix 2. 【0083】 With this configuration, the light guide element is made using a rectangular plate, thus reducing the number of times the plate needs to be processed. Furthermore, because the plate has a simple shape, assembly is easy. 【0084】 (Note 4) The first member has a first incident end face located at the incident end and a first injection end face located at the injection end, The third member has a third incident end face located at the incident end and a third injection end face located at the injection end, The first incident end face and the third incident end face, and at least one of the first exit end face and the third exit end face, are parallel to a plane perpendicular to the optical axis of the optical guide path. The light guide element described in Appendix 2 or Appendix 3. 【0085】 This configuration allows for a smaller gap between the entrance aperture and the light source. Therefore, the entrance aperture and the light source can be positioned closer together. This suppresses the amount of light leakage generated between the light source and the entrance aperture of the light guide element. Furthermore, the gap between the exit aperture and the light modulation element can be reduced. Therefore, the exit aperture and the light modulation element can be positioned closer together. This suppresses the amount of light leakage generated between the exit aperture of the light guide element and the light modulation element. 【0086】 (Note 5) A light guide element described in any one of Appendix 1 to Appendix 4, A first light source that emits first light in the first wavelength band toward the incident end of the light guide path in the light guide element, A first parallelizing element that parallelizes the first light emitted from the exit end of the light guide path, The system comprises a first optical modulator that modulates the first light emitted from the first parallelizing element based on image information, Optical module. 【0087】 This optical module configuration, by incorporating the above-mentioned light guide element, provides a highly reliable optical module that suppresses the reduction in adhesive strength of the adhesive used to bond multiple plate materials. 【0088】 (Note 6) A first image forming module comprising: a first light guide element consisting of a light guide element described in any one of Appendix 1 to Appendix 4; a first light source that emits first light in a first wavelength band toward the first light guide element; a first parallelizing element that parallelizes the first light emitted from the first light guide element; and a first light modulation device that modulates the first light emitted from the first parallelizing element based on image information; A second image forming module comprising: a second light guide element consisting of a light guide element described in any one of Appendix 1 to Appendix 4; a second light source that emits second light in a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element that parallelizes the second light emitted from the second light guide element; and a second light modulation device that modulates the second light emitted from the second parallelizing element based on image information; A third image forming module comprising: a third light guide element comprising a light guide element described in any one of Appendix 1 to Appendix 4; a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band toward the third light guide element; a third parallelizing element that parallelizes the third light emitted from the third light guide element; and a third light modulation device that modulates the third light emitted from the third parallelizing element based on image information; A photosynthetic element that combines light emitted from the first image forming module, light emitted from the second image forming module, and light emitted from the third image forming module, The system comprises a projection optical system that projects light emitted from the photosynthetic element, projector. 【0089】 With this projector configuration, each image-forming module corresponding to the three colors is equipped with the light guide element, thereby suppressing the decrease in adhesive strength due to irradiation with light of each color of the adhesive that bonds the multiple plate materials constituting each light guide element, and thus providing a highly reliable projector. 【0090】 (Note 7) The first image forming module, which consists of the optical modules described in Appendix 5, The second image forming module, The third image forming module, Photosynthetic elements and, Projection optical system and, Equipped with, The second image forming module is, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light uniformizing element is provided, which receives the second light emitted from the second light source and uniformizes the in-plane illuminance of the second light, A second parallelizing element that parallelizes the second light emitted from the light uniformizing element, The system includes a second optical modulator that modulates the second light emitted from the second parallelizing element based on image information, The third image forming module is, A third light source that emits third light in a third wavelength band different from the first and second wavelength bands, The system includes a third light modulator that modulates the third light emitted from the third light source based on image information, The photosynthetic element combines and emits light emitted from the first image forming module, light emitted from the second image forming module, and light emitted from the third image forming module. The projection optical system projects light emitted from the photosynthetic element. projector. 【0091】 This projector configuration provides a highly reliable projector that suppresses the decrease in adhesive strength due to light irradiation of the adhesive bonding the multiple plate materials constituting the first light guide element in at least the first image forming module. 【0092】 (Note 8) The aforementioned light 1 is blue light or green light. The projector described in Appendix 7. 【0093】 Because blue light has a short wavelength, it has the highest energy among the RGB colors, making it prone to degrading adhesive strength. Similarly, green light is the most sensitive to human vision, requiring a greater amount of light compared to other colors to maintain the desired white balance, which also makes it prone to degrading adhesive strength. Thus, by applying the present invention to a light guide element that guides blue or green light, the decrease in adhesive strength of the adhesive can be suppressed more effectively. [Explanation of Symbols] 【0094】 10...Multiple plate materials, 11...First member, 11a...First reflective surface, 11e...First incident end surface, 11f...First injection end surface, 12...Second member, 12a...Second reflective surface, 12e...Second incident end surface, 12f...Second injection end surface, 13...Third member, 13a...Third reflective surface, 13e...Third incident end surface, 13f...Third injection end surface, 14...Fourth member, 14a...Fourth reflective surface, 14e...Fourth incident end surface, 14f...Fourth injection end surface, 41...First light guide element, 41a...Incident end, 41b...Injection end, 41L...Light guide path, 42...Second light guide element, 43...Third light guide element, 45...Incident aperture, 46...Injection aperture, 50...Adhesion Agent, 100B...First image forming module, 100G...Second image forming module, 100R...Third image forming module, 104...Blue light modulator (first light modulator), 105...Green light modulator (second light modulator), 106...Red light modulator (third light modulator), 161...First parallelization element, 162...Second parallelization element, 163...Third parallelization element, 200...Photosynthesis element, 250...Projection optical system, 301...Projector, 401...First light source, 402...Second light source, 403...Third light source, LB...Blue light, LG...Green light, LR...Red light, LL...Leakage light, M...Intermediate section.

Claims

[Claim 1] Multiple plate materials that define the light guide path, which guides light incident from the incident end and emits it from the exit end, An adhesive for bonding the plurality of plate materials outside the light guide path, Equipped with, The plurality of plate materials include a first member having a first reflective surface and a second member having a second reflective surface, The contact area of ​​the adhesive with respect to the first member and the second member is greater from the intermediate portion to the injection end of the light guide than from the intermediate portion to the input end. Light guide element. [Claim 2] The plurality of plate materials further include a third member having a third reflective surface and a fourth member having a fourth reflective surface, The light guide path is configured such that the first reflective surface of the first member and the third reflective surface of the third member face each other, and the second reflective surface of the second member and the fourth reflective surface of the fourth member face each other. The light guide element according to claim 1. [Claim 3] The first member and the third member are composed of a pair of rectangular plates. The second and fourth members are made up of a pair of trapezoidal plates, The light guide path includes a rectangular entrance aperture located at the entrance end and a rectangular exit aperture located at the exit end, The injection opening is larger than the inlet opening. The light guide element according to claim 2. [Claim 4] The first member has a first incident end face located at the incident end and a first injection end face located at the injection end, The third member has a third incident end face located at the incident end and a third injection end face located at the injection end, The first incident end face and the third incident end face, and at least one of the first exit end face and the third exit end face are parallel to a plane perpendicular to the optical axis of the optical guide path. The light guide element according to claim 2 or claim 3. [Claim 5] The light guide element according to claim 1, A first light source that emits first light in the first wavelength band toward the incident end of the light guide path in the light guide element, A first parallelizing element that parallelizes the first light emitted from the exit end of the light guide path, The system comprises a first optical modulator that modulates the first light emitted from the first parallelizing element based on image information, Optical module. [Claim 6] A first image forming module comprising: a first light guide element comprising the light guide element described in claim 1; a first light source that emits first light in a first wavelength band toward the first light guide element; a first parallelizing element that parallelizes the first light emitted from the first light guide element; and a first light modulation device that modulates the first light emitted from the first parallelizing element based on image information. A second image forming module comprising: a second light guide element comprising the light guide element described in claim 1; a second light source that emits second light in a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element that parallelizes the second light emitted from the second light guide element; and a second light modulation device that modulates the second light emitted from the second parallelizing element based on image information; A third image forming module comprising: a third light guide element comprising the light guide element described in claim 1; a third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band toward the third light guide element; a third parallelizing element that parallelizes the third light emitted from the third light guide element; and a third light modulation device that modulates the third light emitted from the third parallelizing element based on image information; A photosynthetic element that combines light emitted from the first image forming module, light emitted from the second image forming module, and light emitted from the third image forming module, The system comprises a projection optical system that projects light emitted from the photosynthetic element, projector. [Claim 7] A first image forming module comprising the optical module described in claim 5, The second image forming module, The third image forming module, Photosynthetic elements and, Projection optical system and, Equipped with, The second image forming module is, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light uniformizing element into which the second light emitted from the second light source is incident and which uniformizes the in-plane illuminance of the second light, A second parallelizing element that parallelizes the second light emitted from the light homogenizing element, The system includes a second optical modulator that modulates the second light emitted from the second parallelizing element based on image information, The third image forming module is, A third light source that emits third light in a third wavelength band different from the first wavelength band and the second wavelength band, The system includes a third light modulator that modulates the third light emitted from the third light source based on image information, The photosynthetic element combines and emits light emitted from the first image forming module, light emitted from the second image forming module, and light emitted from the third image forming module. The projection optical system projects light emitted from the photosynthetic element. projector. [Claim 8] The first light is blue light or green light. The projector according to claim 7.

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