Light guide element, optical module, and projector

Abstract

Provided is a light guide element, an optical module, and a projector, in which the adhesive strength of an adhesive is suppressed from decreasing. The light guide element of the present application has: a plurality of plate members that divide a light guide path that guides light that has entered from an entrance end and emits the light from an exit end; and an adhesive that adheres the plurality of plate members outside the light guide path, the plurality of plate members including: a first member having a first reflection surface; and a second member having a second reflection surface, the contact area of the adhesive with respect to the first member and the second member being greater from a middle portion of the light guide path to the exit end side than from the middle portion to the entrance end side.

Description

Technical Field

[0001] This invention relates to light guide elements, optical modules, and projectors. Background Technology

[0002] Previously, projectors were known to include: 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 amplifies and projects the image light emitted from the light modulation device onto a projection surface such as a screen.

[0003] Patent Document 1 discloses a projector comprising: an LED light source that emits light; a block-shaped light guide element that emits light from the LED light source in a uniform brightness manner from an emitting end; a condenser lens that images 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.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2000-180962

[0005] However, in the aforementioned projector, it is difficult to completely capture the light emitted from the LED light source into the light guide element. The light leaks out through the gap between the light source and the light guide element, exiting to the outside of the light guide element. For example, in the aforementioned projector, a rectangular reflector consisting of four mirrors bonded together with adhesive could be considered instead of a block-shaped light guide element. If such a rectangular reflector is used in a high-brightness projector, the amount of leaked light incident on the adhesive increases, potentially compromising the adhesive's bonding reliability. Summary of the Invention

[0006] To address the aforementioned issues, one embodiment of the present invention provides a light guide element comprising: a plurality of plates dividing a light guide path that guides light incident from an incident end and emitted from an emitting end; and an adhesive that bonds the plurality of plates together on the exterior of the light guide path, the plurality of plates comprising: a first component having a first reflective surface; and a second component having a second reflective surface, wherein the contact area of ​​the adhesive relative to the first component and the second component is greater from the middle portion of the light guide path to the emitting end side than from the middle portion to the incident end side.

[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 of a first wavelength 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 emitting end of the light guide path; and a first light 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 comprises: a first image forming module, comprising: a first light guide element, which is constituted by a light guide element according to one aspect of the present invention; a first light source, which emits first light of a first wavelength band toward the first light guide element; a first parallelizing element, which parallelizes the first light emitted from the first light guide element; and a first light modulation device, which modulates the first light emitted from the first parallelizing element based on image information; and a second image forming module, comprising: a second light guide element, which is constituted by a light guide element according to one aspect of the present invention; a second light source, which emits second light of a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element, which parallelizes the second light emitted from the second light guide element; and a second light modulation device, which modulates the first light emitted from the second light guide element based on image information; and a second image forming module, comprising: a second light guide element, which is constituted by a light guide element according to one aspect of the present invention; a second light source, which emits second light of a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element, which parallelizes the second light emitted from the second light guide element; and a second light modulation device, which modulates the first light emitted from the first light guide element based on image information; and a second image forming module, comprising: a first light guide element, which is constituted by a light guide element according to one aspect of the present invention; a first light source, which emits second light of a second wavelength band different from the first wavelength band toward the second light guide element; a second light ... The system 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, which is configured as a light guide element according to one aspect of the present invention; a third light source, which emits third light of a third band different from the first band and the second band toward the third light guide element; a third parallelizing element, which parallelizes the third light emitted from the third light guide element; a third light modulation device, which modulates the third light emitted from the third parallelizing element based on image information; a light combining element, which combines the light emitted from the first image forming module, the light emitted from the second image forming module, and the light emitted from the third image forming module; and a projection optical system, which projects the light emitted from the light combining element.

[0009] A projector according to one aspect of the present invention comprises a first image forming module, a second image forming module, a third image forming module, a light combining element, and a projection optical system. The second image forming module includes: a second light source emitting second light of a second wavelength band different from the first wavelength band; a light homogenizing element for incident on the second light emitted from the second light source to homogenize the in-plane illuminance of the second light; a second parallelizing element for parallelizing the second light emitted from the light homogenizing element; and a second light modulation device for modulating the second light emitted from the second parallelizing element based on image information. The third image forming module includes: a third light source emitting third light of a third wavelength band different from both the first and second wavelength bands; and a third light modulation device for modulating the third light emitted from the third light source based on image information. The light combining element combines and emits the light emitted from the first image forming module, the light emitted from the second image forming module, and the light emitted from the third image forming module. The projection optical system projects the light emitted from the light combining element. Attached Figure Description

[0010] Figure 1 This is a top view showing the schematic structure of the projector according to an embodiment.

[0011] Figure 2 This is a 3D diagram of a light guide element.

[0012] Figure 3 This is a top view showing the peripheral structure of the light guide element.

[0013] Figure 4 It is along Figure 3 A cross-sectional view along line IV.

[0014] Figure 5 This is a schematic diagram used to illustrate the behavior of leaked light.

[0015] Explanation of reference numerals in the attached figures

[0016] 10: Multiple plates; 11: First component; 11a: First reflective surface; 11e: First incident end face; 11f: First emission end face; 12: Second component; 12a: Second reflective surface; 12e: Second incident end face; 12f: Second emission end face; 13: Third component; 13a: Third reflective surface; 13e: Third incident end face; 13f: Third emission end face; 14: Fourth component; 14a: Fourth reflective surface; 14e: Fourth incident end face; 14f: Fourth emission end face; 41: First light guide element; 41a: Incident end; 41b: Emission end; 41L: Light guide path; 42: Second light guide element; 43: Third light guide element; 45: Incident opening; 46: Emission opening; 50: Adhesive; 100B: First image forming module; 100G: Second image forming module; 100R: Third image forming module; 104: Blue light modulation device (first light modulation device); 105: Green light modulation device (second light modulation device); 106: Red light modulation device (third light modulation device); 161: First parallelization element; 162: Second parallelization element; 163: Third parallelization element; 200: Light combining 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: Leaking light; M: Intermediate part. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described using the accompanying drawings.

[0018] The projector in this embodiment is an example of a liquid crystal projector that uses a liquid crystal panel as a light modulation device.

[0019] In the following figures, the scale of the dimensions is sometimes different depending on the constituent elements so as to facilitate observation of each constituent element.

[0020] Figure 1 This is a top view showing the schematic structure of the projector according to an embodiment.

[0021] like Figure 1 As shown, the projector 301 is an image display device with three liquid crystal panels as light modulation devices, and is a so-called three-panel projector. The projector 301 includes a first image forming module 100B, a second image forming module 100G, a third image forming module 100R, a light combining element 200, and a projection optical system 250.

[0022] The first image forming module 100B has a blue light emitting section 101 and a blue light modulation device (first light modulation device) 104. The second image forming module 100G has a green light emitting section 102 and a green light modulation device (second light modulation device) 105. The third image forming module 100R has a red light emitting section 103 and a red light modulation device (third light modulation device) 106.

[0023] First, the first image forming module 100B will be described. The blue light emitting 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 emitting unit 101 is defined as the D1 direction. One side of the D1 direction is defined as the -D1 side, and the side of the D1 direction opposite to the -D1 side is defined as the +D1 side. The direction perpendicular to the D1 direction within the plane containing the optical axis of the blue light LB is defined as the D2 direction. One side of the D2 direction is defined as the -D2 side, and the side of the D2 direction opposite to the -D2 side is defined as the +D2 side. The direction orthogonal to both the D1 and D2 directions is defined as the D3 direction. The blue light LB emitted from the blue light emitting unit 101 travels along the D1 direction toward the +D1 side.

[0024] The blue light emitting section 101 includes a first light source 401, a first light guide element 41, and a first parallelization 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 surface including directions D2 and D3.

[0025] A first light-emitting element 121 is disposed on the +D1 side of the first substrate 111. The light-emitting surface of the first light-emitting element 121 is the +D1 side, which is opposite to the surface disposed on the first substrate 111. The first light-emitting element 121 emits blue light LB in the blue band of the visible spectrum. The blue band is equivalent to the first band. The blue light LB is equivalent to the first light. The blue light LB is emitted toward the +D1 side with an axis passing through the center of the light-emitting surface of the first light-emitting element 121 and parallel to the D1 direction as its center. The blue band is, for example, the band of 420nm to 500nm. The blue band has the shortest wavelength among the colored lights used in a 3-panel projector, and therefore has high energy.

[0026] The first light-emitting element 121 is, for example, a blue LED that emits blue light LB. Furthermore, the first light-emitting element 121 may be composed of a single LED or multiple LEDs as a whole. When the first light-emitting element 121 is composed of multiple LEDs, the multiple LEDs are arranged in the area occupied by the first light-emitting element 121 within a plane including directions D2 and D3.

[0027] The first light guide element 41 is disposed in the optical path of the blue light LB emitted from the first light source 401, and is positioned on the +D1 side of the first light-emitting element 121 of the first light source 401, and overlaps with the first light-emitting element 121 in the D2 and D3 directions. Details about the first light guide element 41 will be described later.

[0028] The first parallelizing element 161 is disposed in the optical path of the blue light LB emitted from the first light guide element 41. The first parallelizing element 161 parallelizes the blue light LB emitted from the first light guide element 41 along the D1 direction.

[0029] The blue light modulation device 104 has 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 disposed in the optical path of the blue light LB emitted from the first parallelizing element 161.

[0030] The first incident-side polarizing element 171 is positioned closer to the +D1 side than the first parallelizing element 161. The first incident-side polarizing element 171 causes a predetermined polarized light in the blue light LB emitted from the first parallelizing element 161 to be emitted along the D1 direction toward the +D1 side. The first incident-side polarizing element 171 is, for example, a reflective polarizer or an absorptive polarizer.

[0031] The first light modulation element 181 is positioned closer to the +D1 side than the first incident-side polarizing element 171. The first light modulation element 181 modulates the blue light LB emitted from the first incident-side polarizing element 171. The first light modulation element 181 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the first light modulation element 181 modulates the light based on blue image information to generate blue image light IB. The first light modulation element 181 emits the generated image light IB along the D1 direction toward the +D1 side.

[0032] The first emission-side polarizing element 175 is positioned on the +D1 side relative to the first optical modulation element 181. The first emission-side polarizing element 175 emits a predetermined polarized light from the image light IB emitted from the first optical modulation element 181 along the D1 direction toward the +D1 side. The first emission-side polarizing element 175 is, for example, a reflective polarizer or an absorptive polarizer.

[0033] Next, the structure of the first light guide element 41 will be described.

[0034] Figure 2 This is a three-dimensional view of the first light guide element 41. (See diagram below.) Figure 2As shown, the first light guide element 41 divides the light path to guide the blue light LB emitted from the first light-emitting element 121, and propagates the blue light LB to the first light modulation element 181. The first light guide element 41 is composed of multiple plates 10 made of transparent material. The multiple plates 10 include a first component 11, a second component 12, a third component 13, and a fourth component 14.

[0035] The first component 11 and the third component 13 are a pair of rectangular plates. The first component 11 has a first reflective surface 11a on a plane. The third component 13 has a third reflective surface 13a on a plane. The first component 11 and the third component 13 are plates of the same shape.

[0036] The second component 12 and the fourth component 14 are a pair of trapezoidal plates. The second component 12 has a second reflective surface 12a on one plane. The fourth component 14 has a fourth reflective surface 14a on one plane. The second component 12 and the fourth component 14 are plates of the same shape. Hereinafter, without specifically distinguishing between the first reflective surface 11a, the second reflective surface 12a, the third reflective surface 13a, and the fourth reflective surface 14a, they will sometimes be collectively referred to as reflective surface 10a. Reflective surface 10a constitutes a light guide path 41L that guides the blue light LB to the inside of the first light guide element 41.

[0037] Thus, the first light guide element 41 is easily manufactured using four sheets of sheet metal. Furthermore, the first light guide element 41 is constructed using rectangular sheet metal, thereby reducing the number of processing steps required for the sheet metal. In addition, since the sheet metal has a simple shape, assembly becomes easy.

[0038] The first reflective surface 11a of the first component 11 is positioned opposite to the third reflective surface 13a of the third component 13. The second reflective surface 12a of the second component 12 is positioned opposite to the fourth reflective surface 14a of the fourth component 14. The second component 12 and the fourth component 14 are positioned with their upper bottoms against the -D1 side and their lower bottoms against the +D1 side.

[0039] The first reflective surface 11a of the first component 11 is connected to one side of the trapezoidal second component 12 and the fourth component 14, which are the beveled sides. The third reflective surface 13a of the third component 13 is connected to the other side of the second component 12 and the fourth component 14, which are the beveled sides. The plurality of plates 10 are bonded together by the adhesive 50 described later. Thus, the plurality of plates 10 form the shape of the first light guide element 41.

[0040] The first component 11 has a first incident end face 11e at its end on the -D1 side. The second component 12 has a second incident end face 12e at its end on the -D1 side. The third component 13 has a third incident end face 13e at its end on the -D1 side. The fourth component 14 has a fourth incident end face 14e at its end on the -D1 side. A portion of the first incident end face 11e, a portion of 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.

[0041] The first component 11 has a first emission end face 11f at its end on the +D1 side. The second component 12 has a second emission end face 12f at its end on the +D1 side. The third component 13 has a third emission end face 13f at its end on the +D1 side. The fourth component 14 has a fourth emission end face 14f at its end on the +D1 side. The first emission end face 11f, the second emission end face 12f, the third emission end face 13f, and the fourth emission end face 14f form an emission opening 46. The emission opening 46 forms the emission end 41b of the light guide path 41L.

[0042] The incident opening 45 extends parallel to the surface encompassing directions D2 and D3. The shape of the incident opening 45 when viewed from direction D1 is the same as the shape of the emitting surface of the first light-emitting element 121 when viewed from that direction, and is rectangular. The size of the incident opening 45 can be the same as the size of the emitting surface of the first light-emitting element 121, but is preferably appropriately larger than the size of the emitting surface of the first light-emitting element 121.

[0043] The emission opening 46 extends parallel to the surface encompassing directions D2 and D3. The emission opening 46 is larger than the incident opening 45. The shape of the emission opening 46 when viewed from direction D1 is rectangular. The size of the emission end 41b is the same as the size of the first optical modulation element 181.

[0044] According to this structure, the beam width can be increased during the propagation of blue light LB incident from the incident opening 45 within the light guide path. This allows for the generation of blue light LB with a uniform illuminance distribution that efficiently illuminates the entire first light modulation element 181.

[0045] Figure 3 This is a top view showing the peripheral structure of the light guide element. (Example) Figure 3 As shown, the light guide path 41L of the first light guide element 41 has an incident end 41a and an emitted end 41b. The incident end 41a is located on the -D1 side in the D1 direction. The emitted end 41b is located on the +D1 side in the D1 direction.

[0046] Here, the first incident end face 11e and the third incident end face 13e are parallel to the surface including the D2 and D3 directions. In the case of direct bonding with ordinary sheet metal, such as... Figure 3As shown by the dashed lines, the corners of the first incident end face 11e in the first component 11 and the third incident end face 13e in the third component 13 protrude towards the -D1 side. In this embodiment, the corners of the first incident end face 11e and the third incident end face 13e are cut off in a manner 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. The "plane including the D2 and D3 directions" in this embodiment corresponds to the "plane perpendicular to the optical axis of the light guide path" in the claims.

[0047] According to this structure, the gap between the incident opening 45 and the first light source 401 in the D1 direction can be reduced. Therefore, the incident opening 45 and the first light source 401 can be arranged close together in the D1 direction. Therefore, the amount of leakage light LL generated during the period from the first light source 401 toward the incident opening 45 of the first light guide element 41 can be suppressed.

[0048] Furthermore, in this embodiment, the first ejection end face 11f and the third ejection end face 13f are parallel to the plane including the D2 and D3 directions. Similarly, the second ejection end face 12f and the fourth ejection end face 14f are also parallel to the plane including the D2 and D3 directions. The corners of the first ejection end face 11f and the third ejection end face 13f can also be cut off in a manner parallel to the plane including the D2 and D3 directions.

[0049] According to this structure, the gap between the emission opening 46 and the first optical modulation element 181 can be reduced. Therefore, the emission opening 46 and the first optical modulation element 181 can be arranged close together. Therefore, the amount of leakage light LL generated during the period from the emission opening 46 of the first light guide element 41 toward the first optical modulation element 181 can be suppressed.

[0050] 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 surrounded by the incident opening 45, the exit opening 46, and the reflecting surface 10a becomes the light guide path 41L for propagating the blue light LB. Thus, the blue light LB incident on the first light guide element 41 propagates from the -D1 side to the +D1 side within the light guide path 41L.

[0051] 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 an angle smaller than the inclination of the hypotenuse of the trapezoid in the second component 12 and the fourth component 14, without ever incident on the reflecting surface 10a. The remaining portion of the blue light LB incident on the first light guide element 41, forming an angle greater than the aforementioned angle, is incident on the reflecting surface 10a more than once from the incident end 41a, and reaches the exit end 41b after being reflected by the reflecting surface 10a. The path of the blue light LB within the region surrounded by the incident end 41a, the exit end 41b, and the reflecting surface 10a varies depending on the incident angle towards the incident end 41a, involving multiple paths with different numbers of reflections at the reflecting surface 10a. Thus, the illuminance distribution of the blue light LB propagating in the region surrounded by the incident end 41a, the exit end 41b, and the reflecting surface 10a is homogenized within a plane including directions D2 and D3. That is, the first light guide element 41 makes the illuminance distribution of the incident blue light LB uniform in the plane including the D2 and D3 directions. The blue light LB with uniform illuminance distribution is emitted from the emission end 41b towards the +D1 side.

[0052] Next, the adhesive 50 for bonding the multiple plates 10 will be described. The adhesive 50 bonds the multiple plates 10 to the outside of the light guide path, forming a first light guide element 41 having a light guide path 41L. The adhesive 50 is arranged along a portion of the inclined side of the trapezoid in the second component 12 and the fourth component 14. The adhesive 50 is generally positioned closer to the emission end 41b than the middle portion M in the length direction (D1 direction) of the light guide path 41L. Here, the middle portion M of the light guide path 41L refers to a position located equidistant from the incident end 41a and the emission end 41b in the D1 direction.

[0053] In this embodiment, the adhesive 50 is disposed from the injection end 41a toward the injection end 41b to a position of approximately 3 / 4. Alternatively, a portion of the adhesive 50 may be disposed at a position closer to the injection end 41a than the middle portion M.

[0054] Regarding the contact area of ​​the adhesive 50 with respect to the plurality of plates 10, the contact area from the middle portion M of the light guide path to the emission end 41b is greater than the contact area from the middle portion M to the incident end 41a. More specifically, using Figure 4 Please provide an explanation.

[0055] Figure 4 It is along Figure 3 A cross-sectional view along line IV. Figure 4 For ease of observation, we will only focus on the case where adhesive 50 bonds the first component 11 and the second component 12. For example... Figure 3 , Figure 4As shown, the adhesive 50 is located outside the light guide path defined by the first light guide element 41.

[0056] Regarding the first component 11 and the second component 12, one side of the second component 12, which is a beveled portion, abuts against a portion of the first reflective surface 11a of the first component 11. Adhesive 50 bonds the outer side of the light guide path 41L on the first reflective surface 11a to the outer surface 12b of the second component 12, located on the opposite side of the second reflective surface 12a. Thus, regarding the contact area of ​​adhesive 50 with respect to the first component 11 and the second component 12, the contact area from the middle portion M of the light guide path 41L to the emission end 41b is larger than the contact area from the middle portion M to the incident end 41a. In this way, the first component 11 and the second component 12 are bonded via adhesive 50. Similarly, the second component 12 and the third component 13, the third component 13 and the fourth component 14, and the fourth component and the first component 11 are respectively bonded via adhesive 50.

[0057] Furthermore, the adhesive 50 may not be integrally formed along a portion of the inclined side of the trapezoid of the second component 12 and the fourth component 14, and may be configured in multiple interrupted states. The contact area in this embodiment is not limited to the case of continuous contact, but includes the total area of ​​intermittent contact.

[0058] The adhesive 50 can be any type, including UV-curable, natural-curable, and thermosetting types. The adhesive 50 only needs to be able to bond multiple plates 10 together to form the shape of the first light guide element 41, and can be modified appropriately.

[0059] In the first light guide element 41 configured in this way, even when the incident opening 45 is close to the first light source 401, there is a case where a portion of the blue light LB leaks to the outside of the guide light path 41L and becomes leakage light LL. The leakage light LL is generated during the period from the first light source 401 toward the incident opening 45 of the first light guide element 41 and leaks to the outside of the guide light path 41L.

[0060] Here, the behavior of the leaking light LL will be explained. Figure 5 This is a schematic diagram used to illustrate the behavior of leaky light (LL). For example... Figure 5 As shown, the leaked light LL is light emitted from the first light source 401 along an angle larger than the cone angle of the trapezoid formed by the second component 12 and the fourth component 14. The leaked light LL contains various angular components, but the leaked light LL emitted along an angle slightly larger than the cone angle of the trapezoid formed by the second component 12 and the fourth component 14 is more likely to be incident on the side of the incident end 41a side of the first light guide element 41.

[0061] On the other hand, in order for the leaked light LL to reach the side surface of the emitting end 41b of the first light guide element 41, the leaked light LL, which is emitted at an angle equal to the cone angle of the trapezoid formed by the second component 12 and the fourth component 14, needs to travel from the incident end 41a side along the outer surface of the first light guide element 41 to the emitting end 41b side. In this way, the amount of light in the leaked light LL reaching the emitting end 41b side is sufficiently small compared to the amount of light incident on the incident end 41a side.

[0062] Therefore, when the adhesive 50 is placed on the incident end 41a side, the amount of leakage light LL increases, which can easily cause the adhesive 50 to deteriorate.

[0063] In contrast, in the first light guide element 41 of this embodiment, the adhesive 50 is positioned closer to the emission end 41b than the incident end 41a side. Therefore, the leaked light LL leaking from the incident opening 45 of the first light guide element 41 to the outside is less likely to come into contact with the adhesive 50, thus suppressing the deterioration of the adhesive 50. Therefore, the reduction in the bonding strength of the adhesive 50 used to bond multiple plates 10 can be suppressed.

[0064] Thus, the first light guide element 41 of this embodiment includes: a plurality of plates 10 having an incident end 41a and an emitting end 41b, dividing a light guide path for guiding light; and an adhesive 50 that bonds the plurality of plates 10 to the outside of the light guide path 41L. The plurality of plates 10 include: a first component 11 having a first reflective surface 11a; and a second component 12 having a second reflective surface 12a. Regarding the contact area of ​​the adhesive 50 with respect to the first component 11 and the second component 12, the contact area from the middle portion M of the light guide path to the emitting end 41b side is greater than the contact area from the middle portion M to the incident end 41a side.

[0065] According to the first light guide element 41 of this embodiment, since the adhesive 50 is positioned closer to the emission end 41b than the incident end 41a side, the leaked light LL leaking from the incident opening 45 of the first light guide element 41 to the outside is less likely to come into contact with the adhesive 50, thus suppressing the deterioration of the adhesive 50. Therefore, the reduction in the bonding strength of the adhesive 50 used to bond multiple plates 10 can be suppressed.

[0066] Furthermore, compared to the case where all the multiple plates 10 are trapezoidal, the bonding surface between the adhesive 50 and the multiple plates 10 can be expanded, making it easier to apply the adhesive 50 and facilitating assembly. Thus, the first image forming module 100B of this embodiment includes a first light guide element 41, a first light source 401, a first parallelization element 161, and a first light modulation device 104.

[0067] According to the first image forming module 100B of this embodiment, since it has a first light guide element 41, it is possible to provide a highly reliable optical module that suppresses the reduction of the bonding strength of the adhesive 50 that bonds multiple plates 10.

[0068] Next, the second image forming module 100G will be described. The green light emitting section 102 of the second image forming module 100G is positioned closer to the +D1 side and the -D2 side than the blue light emitting section 101, and is located in the region overlapping with the blue light emitting section 101 in the D3 direction. The green light emitting section 102 emits green light LG. The green light LG emitted from the green light emitting section 102 travels along the D2 direction towards the +D2 side.

[0069] The green light emitting section 102 includes a second light source 402, a second light guide element 42, and a second parallelization 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 surface including directions D1 and D3.

[0070] The second light-emitting element 122 is disposed on the +D2 side of the second substrate 112. The light-emitting surface of the second light-emitting element 122 is the +D2 side, which is opposite to the surface disposed on the second substrate 112. The second light-emitting element 122 emits green light LG in the green band of the visible spectrum. The green band is equivalent to the second band. The green light LG is equivalent to the second light. The green light LG is emitted toward the +D2 side with an axis passing through the center of the light-emitting surface of the second light-emitting element 122 and parallel to the D2 direction as its center. The green band is, for example, the 500nm to 600nm band. In addition, the green band is easily recognized by the human eye, so a large amount of light is required when projected onto the SCR screen. The second light-emitting element 122 is the same as the first light-emitting element 121, for example, composed of an LED that emits green light LG.

[0071] The second light guide element 42 is disposed in the optical path of the green light LG emitted from the second light source 402. The structure of the second light guide element 42 is the same as that of the first light guide element 41, and it has a light guide path for guiding the green light LG.

[0072] 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.

[0073] The green light modulation device 105 has a second incident-side polarizing element 172, a second light modulation element 182, and a second exit-side polarizing element 176. The green light modulation device 105 is disposed in the optical path of the green light LG emitted from the second parallelizing element 162.

[0074] The second incident-side polarizing element 172, like the first incident-side polarizing element 171, causes the prescribed polarized light in the green light LG emitted from the second parallelizing element 162 to be emitted along the D2 direction toward the +D2 side.

[0075] The second optical modulation element 182, like the first optical modulation element 181, modulates the green light LG emitted from the second incident side polarizing element 172. The second optical modulation element 182 generates a green image light IG based on the green image information. The second optical modulation element 182 emits the image light IG along the D2 direction toward the +D2 side.

[0076] The second emission-side polarizing element 176, like the first emission-side polarizing element 175, emits a predetermined polarized light from the image light IG emitted from the second optical modulation element 182 along the D2 direction toward the +D2 side.

[0077] Thus, the second image forming module 100G of this embodiment has a second light guide element 42, a second light source 402, a second parallelization element 162, and a second light modulation device 105.

[0078] According to the second image forming module 100G of this embodiment, the structure 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 the reduction of the bonding strength of the adhesive 50 that bonds multiple plates 10.

[0079] Next, the third image forming module 100R will be described. The red light emitting unit 103 of the third image forming module 100R is positioned at a position closer to the +D1 side than the green light emitting unit 102, and is located in the region overlapping with the blue light emitting unit 101 in the D2 and D3 directions. The red light emitting unit 103 emits red light LR. The red light LR emitted from the red light emitting unit 103 travels along the D1 direction towards the -D1 side.

[0080] 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 surface including the D2 direction and the D3 direction.

[0081] The third light-emitting element 123 is disposed on the -D1 side of the third substrate 113. The light-emitting surface of the third light-emitting element 123 is the surface opposite to the surface disposed on the third substrate 113, on the -D1 side. The third light-emitting element 123 emits red light LR in the red band of the visible spectrum. The red band is equivalent to the third band. The red light LR is equivalent to the third light. The red light LR is emitted toward the -D1 side with an axis passing through the center of the light-emitting surface of the third light-emitting element 123 and parallel to the D1 direction as its center. The red band is, for example, the band of 610nm to 700nm. The third light-emitting element 123 is the same as the first light-emitting element 121 and the second light-emitting element 122, for example, constituted by an LED that emits red light LR.

[0082] The third light guide element 43 is disposed in the optical path of the red light LR emitted from the third light source 403. The structure of the third light guide element 43 is the same as that of the first light guide element 41, and it has a light guide path for guiding the red light LR.

[0083] 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.

[0084] The red light modulation device 106 has a third incident-side polarizing element 173, a third light modulation element 183, and a third emission-side polarizing element 177. The red light modulation device 106 is arranged in the optical path of the red light LR emitted from the third parallelizing element 163.

[0085] The third incident-side polarizing element 173, like the first incident-side polarizing element 171 and the second incident-side polarizing element 172, causes the prescribed polarized light in the red light LR emitted from the third parallelizing element 163 to be emitted along the D1 direction toward the -D1 side.

[0086] The third optical modulation element 183, like the first optical modulation element 181 and the second optical modulation element 182, modulates the red light LR emitted from the third incident side polarizing element 173. The third optical modulation element 183 generates red image light IR. The third optical modulation element 183 emits image light IR along the D1 direction toward the -D1 side.

[0087] The third emission-side polarizing element 177, like the first emission-side polarizing element 175 and the second emission-side polarizing element 176, emits a predetermined polarized light from the image light IR emitted from the third optical modulation element 183 along the D1 direction toward the -D1 side.

[0088] The light combining element 200 is disposed 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 light combining element 200 combines the image lights IB, IG, and IR emitted from the first emission side polarizing element 175, the second emission side polarizing element 176, and the third emission side polarizing element 177, and emits the generated image light IM along the D2 direction toward the +D2 side.

[0089] The projection optical system 250 is positioned in the optical path of the image light IM emitted from the light synthesizing element 200. The projection optical system 250 projects the image input to the first light modulation element 181, the second light modulation element 182, and the third light modulation element 183 onto the screen SCR, magnifying and displaying the image on the screen SCR.

[0090] Thus, the third image forming module 100R of this embodiment has a third light guide element 43, a third light source 403, a third parallelization element 163, and a third light modulation device 106.

[0091] According to the third image forming module 100R of this embodiment, the structure of the third light guide element 43 is the same as that of the first light guide element 41. Therefore, similar to the first image forming module 100B, the third image forming module 100R can provide a highly reliable optical module that suppresses the reduction of the bonding strength of the adhesive 50 that bonds multiple plates 10.

[0092] Thus, the projector of this embodiment includes: a first image forming module 100B, which has a first light guide element 41, a first light source 401, a first parallelization element 161, and a first light modulation device 104; a second image forming module 100G, which has a second light guide element 42, a second light source 402, a second parallelization element 162, and a second light modulation device 105; a third image forming module 100R, which has a third light guide element 43, a third light source 403, a third parallelization element 163, and a third light modulation device 106; a light combining element; and a projection optical system.

[0093] According to the projector 301 of this embodiment, since each image forming module 100B, 100G, 100R corresponding to the three colors is equipped with the above-mentioned light guide elements 41, 42, 43, it is possible to provide a highly reliable projector that suppresses the reduction of the adhesive strength of the adhesive constituting the multiple plates 10 of each light guide element 41, 42, 43 caused by the irradiation of light of each color.

[0094] Furthermore, in the projector 301 described above, the example given is that 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 thereto. For example, the optical module of the present invention can be applied to only one color of the first image forming module 100B, the second image forming module 100G, and the third image forming module 100R, or it can 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 that uses an optical module corresponding to blue light LB or green light LG as the first image forming module. For example, in the case of a projector that only has the first image forming module 100B described above, the second image forming module may have a second light source 402 that emits green light LG, a light homogenizing element that homogenizes the in-plane illuminance of green light LG instead of the light guide element of the present invention, a second parallelizing element 162 that parallelizes the green light LG emitted from the light homogenizing element, and a green light modulation device 105. Furthermore, the third image forming module may have a third light source 403 that emits red light LR and a red light modulation device 106. Alternatively, the third image forming module may also have, like the second image forming module, a third parallelization element 163 that parallelizes the red light LR and a light homogenization element that homogenizes the in-plane illuminance of the red light LR.

[0095] Furthermore, when applying the optical module of the present invention to an image forming module for two colors, it is preferable to apply it to an image forming module for blue light (LB) and green light (LG).

[0096] The reasons given above are as follows: Blue light (LB) has a short wavelength, resulting in the highest energy among the RGB colors, which easily leads to a deterioration in adhesive strength. Additionally, the human eye has the highest visual sensitivity for green light (LG), requiring a greater amount of light than other colors to maintain the desired white balance, which also easily leads to a deterioration in adhesive strength. Therefore, by applying this invention to the light guide element that guides blue light (LB) or green light (LG), the reduction in the adhesive strength of the adhesive 50 can be more effectively suppressed.

[0097] Furthermore, in this embodiment, the case where the plurality of plates 10 are composed of four plates has been described, but they can also be composed of two plates. More specifically, the first component 11 and the second component 12 can also be integrally formed. Similarly, the third component 13 and the fourth component 14 can also be integrally formed.

[0098] The following is a summary published in this note.

[0099] (Note 1)

[0100] A light guide element includes: a plurality of plates that divide a light guide path for guiding light incident from an incident end and emitted from an emitting end; and an adhesive for bonding the plurality of plates together on the outside of the light guide path, the plurality of plates comprising: a first component having a first reflective surface; and a second component having a second reflective surface, wherein the contact area of ​​the adhesive relative to the first component and the second component is greater from the middle portion of the light guide path to the emitting end side than from the middle portion to the incident end side.

[0101] Sometimes, some light leaks outwards from the light guide path, becoming leakage light. Leaking light is light emitted towards the outer sides of the outer surfaces of multiple plates. While leakage light contains various angular components, it tends to easily strike the side of the light guide element's incident end, especially when emitted in a direction away from the outer surfaces of the plates. On the other hand, for the leakage light to reach the side of the light guide element's emitting end, it needs to travel along the outer surfaces of the multiple plates. Thus, the amount of leakage light reaching the emitting end is sufficiently small compared to the amount incident on the incident end. Therefore, when the adhesive is placed on the incident end, the increased amount of leakage light can easily cause adhesive degradation. In contrast, with this light guide element structure, since the adhesive is placed further away from the emitting end than the incident end, leakage light leaking from the incident opening of the light guide element is less likely to contact the adhesive, thus suppressing adhesive degradation. Therefore, it is possible to suppress the reduction in the adhesive strength of the adhesive bonding the multiple plates.

[0102] (Note 2)

[0103] According to the light guide element described in Appendix 1, the plurality of plates further include: a third component having a third reflective surface; and a fourth component having a fourth reflective surface, wherein the light guide path is configured such that: the first reflective surface of the first component faces the third reflective surface of the third component, and the second reflective surface of the second component faces the fourth reflective surface of the fourth component.

[0104] Based on this structure, the light guide element can be easily manufactured using four sheets of material.

[0105] (Note 3)

[0106] According to the light guide element described in Appendix 2, the first component and the third component are composed of a pair of rectangular plates, the second component and the fourth component are composed of a pair of trapezoidal plates, and the light guide path includes a rectangular entrance opening located at the entrance end and a rectangular exit opening located at the exit end, wherein the exit opening is larger than the entrance opening.

[0107] According to this structure, the light guide element is constructed using rectangular sheet material, thus reducing the number of times the sheet material needs to be processed. Furthermore, because the sheet material has a simple shape, assembly becomes easy.

[0108] (Note 4)

[0109] According to Appendix 2 or 3, the first component has a first incident end face located at the incident end and a first emission end face located at the emission end, and the third component has a third incident end face located at the incident end and a third emission end face located at the emission end, wherein the first incident end face and the third incident end face, or the first emission end face and the third emission end face, are parallel to a plane perpendicular to the optical axis of the light guide path.

[0110] According to this structure, the gap between the incident opening and the light source can be reduced. Therefore, the incident opening and the light source can be positioned close together. Thus, the amount of leakage light generated during the period from the light source toward the incident opening of the light guide element can be suppressed. Furthermore, the gap between the exit opening and the light modulation element can be reduced. Therefore, the exit opening and the light modulation element can be positioned close together. Thus, the amount of leakage light generated during the period from the exit opening of the light guide element toward the light modulation element can be suppressed.

[0111] (Note 5)

[0112] According to Appendix 2 or 3, the first component has a first incident end face at the incident end and a first emission end face at the emission end, and the third component has a third incident end face at the incident end and a third emission end face at the emission end, wherein the first incident end face and the third incident end face, as well as the first emission end face and the third emission end face, are parallel to a plane perpendicular to the optical axis of the light guide path.

[0113] According to this structure, the gap between the incident opening and the light source can be reduced. Therefore, the incident opening and the light source can be positioned close together. Thus, the amount of leakage light generated during the period from the light source toward the incident opening of the light guide element can be suppressed. Furthermore, the gap between the exit opening and the light modulation element can be reduced. Therefore, the exit opening and the light modulation element can be positioned close together. Thus, the amount of leakage light generated during the period from the exit opening of the light guide element toward the light modulation element can be suppressed.

[0114] (Note 6)

[0115] An optical module comprising: a light guide element as described in any one of Annexes 1 to 5; a first light source that emits first light of a first wavelength 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 emitting end of the light guide path; and a first light modulation device that modulates the first light emitted from the first parallelizing element based on image information.

[0116] The optical module based on this structure, by having the aforementioned light guiding element, can provide a highly reliable optical module that suppresses the reduction in the bonding strength of adhesives used to bond multiple plates.

[0117] (Note 7)

[0118] A projector comprising: a first image forming module comprising: a first light guide element comprising a light guide element as described in any one of Appendices 1 to 5; a first light source emitting first light of a first wavelength band toward the first light guide element; a first parallelizing element parallelizing the first light emitted from the first light guide element; and a first light modulation device modulating the first light emitted from the first parallelizing element based on image information; and a second image forming module comprising: a second light guide element comprising a light guide element as described in any one of Appendices 1 to 5; a second light source emitting second light of a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element parallelizing the second light emitted from the second light guide element; and a second light modulation device, comprising: a first light guide element comprising ... The system modulates the second light emitted from the second parallelizing element based on image information; and a third image forming module comprising: a third light guide element composed of any one of the light guide elements described in Appendix 1 to Appendix 5; a third light source emitting third light of a third band different from the first band and the second 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 light combining element that combines the light emitted from the first image forming module, the light emitted from the second image forming module, and the light emitted from the third image forming module; and a projection optical system that projects the light emitted from the light combining element.

[0119] According to the projector with this structure, each image forming module corresponding to the three colors has the aforementioned light guide element. Therefore, it is possible to provide a highly reliable projector that suppresses the reduction in the adhesive strength of the adhesives constituting the multiple plates of each light guide element caused by the irradiation of each color light.

[0120] (Postscript 8)

[0121] A projector comprising: a first image forming module comprising the optical module described in Appendix 6; a second image forming module; a third image forming module; a light combining element; and a projection optical system, wherein the second image forming module comprises: a second light source emitting second light of a second wavelength band different from a first wavelength band; a light homogenizing element for incident on the second light emitted from the second light source to homogenize the in-plane illuminance of the second light; a second parallelizing element for parallelizing the second light emitted from the light homogenizing element; and a second light modulation device for modulating the second light emitted from the second parallelizing element based on image information; the third image forming module comprises: a third light source emitting third light of a third wavelength band different from the first and second wavelength bands; and a third light modulation device for modulating the third light emitted from the third light source based on image information; the light combining element combining and emitting the light emitted from the first image forming module, the light emitted from the second image forming module, and the light emitted from the third image forming module; and the projection optical system projecting the light emitted from the light combining element.

[0122] According to the projector structure, a highly reliable projector can be provided that suppresses the reduction in adhesive strength caused by light irradiation of the adhesive used to bond multiple plates constituting the first light guide element in at least the first image forming module.

[0123] (Note 9)

[0124] According to the projector described in Appendix 8, the first light is blue light or green light.

[0125] Blue light has a short wavelength and therefore the highest energy among the RGB colors, which can easily lead to a deterioration in adhesive strength. Furthermore, the human eye has the highest visual sensitivity to green light, requiring a greater amount of light compared to other colors to maintain the desired white balance, which can also easily lead to a deterioration in adhesive strength. Therefore, by applying this invention to light guide elements that guide blue or green light, the reduction in adhesive strength can be more effectively suppressed.

Claims

1. A light guide element, comprising: Multiple plates, which divide the light path, guide light incident from the incident end and emitted from the emitting end; and An adhesive is used to bond the plurality of plates together on the outside of the light guide path. The plurality of plates include: a first component having a first reflective surface; and a second component having a second reflective surface. Regarding the contact area of ​​the adhesive relative to the first component and the second component, the contact area from the middle portion of the light guide to the emission end side is greater than the contact area from the middle portion to the incident end side.

2. The light guide element according to claim 1, wherein, The plurality of plates further include: a third component having a third reflective surface; and a fourth component having a fourth reflective surface. The light guide path is configured such that the first reflective surface of the first component faces the third reflective surface of the third component, and the second reflective surface of the second component faces the fourth reflective surface of the fourth component.

3. The light guide element according to claim 2, wherein, The first component and the third component are composed of a pair of rectangular plates. The second component and the fourth component are composed of a pair of trapezoidal plates. The light guide path includes a rectangular entrance opening located at the entrance end and a rectangular exit opening located at the exit end. The ejection opening is larger than the incident opening.

4. The light guide element according to claim 2 or 3, wherein, The first component has a first incident end face located at the incident end and a first ejection end face located at the ejection end. The third component has a third incident end face located at the incident end and a third ejection end face located at the ejection end. The first incident end face and the third incident end face, or the first emission end face and the third emission end face, are parallel to a plane perpendicular to the optical axis of the light guide path.

5. The light guide element according to claim 2 or 3, wherein, The first component has a first incident end face located at the incident end and a first ejection end face located at the ejection end. The third component has a third incident end face located at the incident end and a third ejection end face located at the ejection end. The first incident end face and the third incident end face, as well as the first emission end face and the third emission end face, are parallel to the plane perpendicular to the optical axis of the light guide path.

6. An optical module having: The light guide element as described in claim 1; A first light source emits a first light of a first wavelength toward the incident end of the light guide path in the light guide element; A first parallelizing element, which parallelizes the first light emitted from the emitting end of the light guide; and A first optical modulation device modulates the first light emitted from the first parallelizing element based on image information.

7. A projector comprising: A first image forming module includes: a first light guide element, which is composed of the light guide element of claim 1; a first light source, which emits first light of a first wavelength toward the first light guide element; a first parallelizing element, which parallelizes the first light emitted from the first light guide element; and a first light modulation device, which modulates the first light emitted from the first parallelizing element based on image information. The second image forming module includes: a second light guide element, which is composed of the light guide element as described in claim 1; a second light source, which emits second light of a second wavelength band different from the first wavelength band toward the second light guide element; a second parallelizing element, which parallelizes the second light emitted from the second light guide element; and a second light modulation device, which 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, which is composed of the light guide element as described in claim 1; a third light source, which emits a third light of a third band different from the first band and the second band toward the third light guide element; a third parallelizing element, which parallelizes the third light emitted from the third light guide element; and a third light modulation device, which modulates the third light emitted from the third parallelizing element based on image information. A light combining 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 light emitted from the photosynthesizing element.

8. A projector comprising: The first image forming module is composed of the optical module as described in claim 6; Second image forming module; Third image forming module; Photosynthetic elements; and Projection optical system, The second image forming module has: The second light source emits a second light of a second wavelength different from the first wavelength; A light homogenizing element that provides incident light from the second light source and homogenizes the in-plane illuminance of the second light. A second parallelizing element, which parallelizes the second light emitted from the light homogenizing element; and The second optical modulation device modulates the second light emitted from the second parallelizing element based on image information. The third image forming module has: A third light source emits a third light in a third band, different from the first and second bands; and The third light modulation device modulates the third light emitted from the third light source based on image information. The light combining element combines and emits the light emitted from the first image forming module, the light emitted from the second image forming module, and the light emitted from the third image forming module. The projection optical system projects light emitted from the photosynthesizing element.

9. The projector according to claim 8, wherein, The first light is blue or green light.

Images