Image forming module and projector

Abstract

This invention provides an image forming module and projector that enable miniaturization of the device configuration. [Solution] The image forming module of the present invention comprises a first light source that emits first light in a first wavelength band, a second light source that emits second light in a second wavelength band different from the first wavelength band, a light guide element that guides the first light emitted from the first light source and the second light emitted from the second light source internally and emits the first light and the second light from a single emission end, and a light modulation device that modulates the light emitted from the light guide element according to image information, wherein the light guide element includes a first incident end into which the first light emitted from the first light source is incident and has a leading light section that guides the first light, and a first secondary light guide section including a second incident end into which the second light emitted from the second light source is incident and merges the second light with the leading light section.

Description

Technical Field

[0001] The present invention relates to an image forming module and a projector.

Background Art

[0002] Conventionally, a projector including a light source that emits color light, an optical modulation device that modulates the color 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 optical modulation device onto a projection surface such as a screen is known. For example, the projector includes a light source device having a blue light source that emits blue light, an excitation light source that is provided separately from the blue light source and emits blue light, and a phosphor that is excited by the blue light emitted from the excitation light source and emits yellow light. In such a projector, white light including blue light and yellow light is emitted from the light source device, and each color light included in the white light is converted into image light by a common optical modulation device or optical modulation devices arranged for each color light.

[0003] For example, Patent Document 1 discloses a projector in which a plurality of light emitting diodes (LEDs) are used as light emitting elements of a light source. In the projector disclosed in Patent Document 1, the color light emitted from each LED is overlapped on the same path in the same direction after passing through a block, modulated by an optical modulation element, and enlarged and projected by a projection lens.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above-mentioned projector requires multiple blocks corresponding to each color of light, as well as a combining prism to combine the light that has passed through each block. This presented a challenge in that the projector's device configuration became large. [Means for solving the problem]

[0006] To solve the above problems, according to one aspect of the present invention, an image forming module is provided comprising: a first light source that emits first light in a first wavelength band; a second light source that emits second light in a second wavelength band different from the first wavelength band; a light guide element that guides the first light emitted from the first light source and the second light emitted from the second light source internally and emits the first light and the second light from a single emission end; and a light modulation device that modulates the light emitted from the light guide element according to image information, wherein the light guide element includes a first incident end into which the first light emitted from the first light source is incident and has a leading light section that guides the first light, and a first secondary light guide section that includes a second incident end into which the second light emitted from the second light source is incident and has the second light merge with the leading light section.

[0007] Furthermore, according to another aspect of the present invention, a projector is provided comprising an image forming module according to the above embodiment and a projection optical system for projecting light emitted from the image forming module. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the configuration of the projector according to the first embodiment. [Figure 2] This is a perspective view showing the main components of the light guide element. [Figure 3] This figure shows the main components of the image forming module in this modified example. [Figure 4] This is a perspective view showing the main components of the light guide element of the second embodiment. [Figure 5] This is a cross-sectional view of the light guide element of the second embodiment. [Figure 6] This is a cross-sectional view of the light guide element of the third embodiment. [Figure 7]This is a cross-sectional view of the light guide element according to the fourth embodiment. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described below with reference to the drawings. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see.

[0010] (First Embodiment) Figure 1 is a schematic diagram showing the configuration of the projector 100 according to the first embodiment. The projector 100 is an image display device equipped with a single liquid crystal panel as an optical modulation device, and is a so-called single-chip projector. As shown in Figure 1, the projector 100 comprises an image forming module 1 and a projection optical system 5.

[0011] The image forming module 1 includes a green light source (first light source) 11, a red light source (second light source) 12, a blue light source (third light source) 13, a light guide element 50, a parallelizing element 16, and a light modulation device 20.

[0012] The green light source 11 emits green light (first light) LG. In the following description, the direction parallel to the optical axis of the green light LG emitted from the green light source 11 is referred to as the D1 direction. One side in the D1 direction is referred to as the -D1 side, and the side opposite to the -D1 side in the D1 direction is referred to as the +D1 side. The direction perpendicular to the D1 direction within the plane containing the optical axis of the green light LG is referred to as the D2 direction. One side in the D2 direction is referred to as the -D2 side, and the side opposite to the -D2 side in the D2 direction is referred to as the +D2 side. The direction perpendicular to both the D1 and D2 directions is referred to as the D3 direction. The green light LG emitted from the green light source 11 travels along the D1 direction towards the +D1 side.

[0013] The green light source 11 comprises a substrate 11a and a green light-emitting element 11b supported on the substrate 11a. The substrate 11a is made of, for example, metal and also acts as a heat dissipation member, receiving heat from the green light-emitting element 11b that emits green light LG and releasing that heat into the external space. The green light-emitting element 11b is provided on the +D1 side of the substrate 11a, which is a plate surface parallel to the plane including the D2 and D3 directions. The green light-emitting element 11b emits green light LG in the green wavelength band of the visible wavelength band. The green wavelength band corresponds to the first wavelength band. The green light LG corresponds to the first light. The light-emitting surface of the green light-emitting element 11b is arranged substantially parallel to the plane including the D2 and D3 directions, and is the surface on the green light-emitting element 11b opposite in the D1 direction to the surface of the substrate 11a that faces the +D1 side. The green light LG diverges from the light-emitting surface of the green light-emitting element 11b, passing through the center of the light-emitting surface of the green light-emitting element 11b and around an axis parallel to the D1 direction, according to a predetermined radiation angle, and is emitted towards the +D1 side. The green wavelength band is, for example, the wavelength band of 500 nm to 600 nm.

[0014] The green light-emitting element 11b is composed of, for example, LEDs that emit green light LG. The green light-emitting element 11b may consist of a single LED or of multiple LEDs. When the green light-emitting element 11b is composed of multiple LEDs, the multiple LEDs are arranged in the region occupied by the green light-emitting element 11b in a plane including the D2 and D3 directions.

[0015] The red light source 12 emits red light (secondary light) LR. The red light LR emitted from the red light source 12 travels along the D2 direction towards the -D2 side. The red light source 12 has the same configuration as the green light source 11, except that the color of the light it emits is different. For this reason, the explanation of the configuration of the red light source 12 will be omitted or simplified.

[0016] The red light source 12 includes a substrate 12a and a red light-emitting element 12b supported by the substrate 12a. The red light-emitting element 12b is provided on the -D2 side plate surface among the plate surfaces parallel to the surface including the D2 direction and the D3 direction on the substrate 12a. The red light-emitting element 12b emits red light LR in the red wavelength band in the visible wavelength band. The red wavelength band corresponds to the second wavelength band. The red light LR corresponds to the second light. The light-emitting surface of the red light-emitting element 12b is arranged substantially parallel to the surface including the D2 direction and the D3 direction, and is the surface on the opposite side of the D2 direction from the surface facing the -D2 side plate surface of the substrate 12a in the red light-emitting element 12b. The red light LR diverges from the light-emitting surface of the red light-emitting element 12b according to a predetermined emission angle around an axis parallel to the D2 direction passing through the center of the light-emitting surface of the red light-emitting element 12b, and is emitted toward the -D2 side. The red wavelength band is, for example, a wavelength band of 610 nm to 700 nm.

[0017] The red light-emitting element 12b is constituted by, for example, an LED that emits the red light LR. Note that the red light-emitting element 12b may be constituted by one LED or may be constituted by a plurality of LEDs in total.

[0018] The blue light source 13 emits blue light (third light) LB along the D2 direction toward the +D2 side. Similar to the green light source 11 and the red light source 12, the blue light source 13 includes a substrate 13a and a blue light-emitting element 13b. The blue light-emitting element 13b is provided on the +D2 side plate surface among the plate surfaces parallel to the surface including the D1 direction and the D3 direction on the substrate 13a. The blue light-emitting element 13b emits blue light LB in the blue wavelength band in the visible wavelength band. The blue wavelength band corresponds to the third wavelength band. The blue light LB corresponds to the third light. The light-emitting surface of the blue light-emitting element 13b is arranged substantially parallel to the surface including the D1 direction and the D3 direction, and is the surface on the opposite side of the D2 direction from the surface contacting the +D2 side plate surface of the substrate 13a in the blue light-emitting element 13b. The blue light LB diverges from the light-emitting surface of the blue light-emitting element 13b according to a predetermined emission angle around an axis parallel to the D2 direction passing through the center of the light-emitting surface of the blue light-emitting element 13b, and is emitted toward the +D2 side. The blue wavelength band is, for example, a wavelength band of 420 nm to 500 nm. The blue light-emitting element 13b is composed of, for example, an LED that emits blue light LB. Note that the blue light-emitting element 13b may be composed of one LED or may be composed of a plurality of LEDs in total.

[0019] The light guide element 50 guides the respective color lights LG, LR, and LB emitted from the light sources 11, 12, and 13 inside and emits the illumination light L from one emission end.

[0020] FIG. 2 is a perspective view showing a main part configuration of the light guide element 50. As shown in FIG. 2, the light guide element 50 has a main light guide part 150, a first sub-light guide part 151, and a second sub-light guide part 152. The main light guide part 150 has a first incident end 150a into which the green light LG emitted from the green light source 11 is incident, an emission end 150b that emits the green light LG from the +D1 side, a first side surface 150s and a first reflection surface 150r that extend between the first incident end 150a and the emission end 150b in the D1 direction. The main light guide part 150 has a first optical axis 150C passing through the center of the first incident end 150a and the center of the emission end 150b.

[0021] The first incident end 150a extends parallel to a plane including the D2 direction and the D3 direction. The shape of the first incident end 150a when viewed from the D1 direction is the same as the shape of the light emitting surface of the green light-emitting element 11b when viewed from the same direction, and is, for example, rectangular.

[0022] The emission end 150b extends parallel to a plane including the D2 direction and the D3 direction and is larger than the first incident end 150a. The shape of the emission end 150b when viewed from the D1 direction is the same as the shape of the modulation surface of the light modulation element 21 of the light modulation device 20 when viewed from the same direction, is similar to the modulation surface of the light modulation element 21, and is, for example, rectangular. The size of the emission end 150b in the plane including the D2 direction and the D3 direction is equivalent to the size of the modulation surface of the light modulation element 21 in the plane including the D2 direction and the D3 direction. The first side surface 150s and the first reflection surface 150r connect the peripheral edge of the first incident end 150a and the peripheral edge of the emission end 150b in the D1 direction.

[0023] The leading light unit 150 of this embodiment is composed of a reflector made of a transparent material such as optical glass. The reflector is a hollow optical member having a frame. When viewed along the D1 direction, the -D1 end of the reflector frame has the same shape as the first incident end 150a and the light-emitting surface of the green light-emitting element 11b, and is formed to the same size as the light-emitting surface of the green light-emitting element 11b, for example, in the shape of a rectangular frame. The +D1 end of the reflector frame has the same shape and size as the exit end 150b and the modulation surface of the light modulation element 21, and is formed to the same size as, for example, a rectangular frame with a different size from the -D1 end.

[0024] Since the shape of the first incident end 150a and the exit end 150b when viewed from the D1 direction is rectangular, the main light section 150, which consists of a reflector, is composed of four trapezoidal plate-shaped members. The length of the side parallel to the D2 or D3 direction on the -D1 side, which corresponds to the upper base of the four plate-shaped members, is set according to the size of the first incident end 150a and the light-emitting surface of the green light-emitting element 11b in the D2 or D3 direction. The length of the side parallel to the D2 or D3 direction on the +D1 side, which corresponds to the lower base of the four plate-shaped members, is set according to the size of the exit end 150b and the modulation surface of the light modulation element 21 in the D2 or D3 direction.

[0025] In the leading light section 150 of this embodiment, the outer surfaces of the four plate-shaped members correspond to the first side surface 150s, and a reflective film 161 made of a dielectric multilayer film or the like is provided on the inner surface of the four plate-shaped members, thereby functioning as the first reflective surface 150r. A portion of the green light LG that enters the interior of the reflector of the leading light section 150 from the first incident end 150a is reflected by the first reflective surface 150r made of the reflective film 161 and propagates toward the +D1 side. In addition, in the main light unit 150, a reflective film 161 may be formed on the plate surface of the plate-shaped member constituting the reflector that faces the external space, and this can be used as the first reflective surface 150r.

[0026] The green light LG emitted from the green light source 11 enters the main light source 150 from the first incident end 150a. The main light source 150 equalizes the in-plane illuminance of the green light LG that guides through its interior, as described later. In the main light source 150, the region enclosed by the first incident end 150a, the exit end 150b, and the first reflective surface 150r is the region where the green light LG mainly propagates. The in-plane size of the region enclosed by the first incident end 150a, the exit end 150b, and the first reflective surface 150r, including the D2 and D3 directions, increases as you move from the -D1 side to the +D1 side in the D1 direction. Furthermore, the shape of the region enclosed by the first incident end 150a, the exit end 150b, and the first reflective surface 150r, including the D2 and D3 directions, changes from the shape of the light-emitting surface of the green light-emitting element 11b as viewed from the D1 direction to the shape of the modulation surface of the optical modulation element 21 as you move from the -D1 side to the +D1 side.

[0027] The first side surface 150s and the first reflective surface 150r, provided on the plate-shaped member constituting the leading light section 150, form a predetermined angle with respect to the first optical axis 150C, and move away from the imaginary line in a plane including the D2 and D3 directions as it moves from the -D1 side to the +D1 side. The green light LG incident on the leading light section 150 propagates from the -D1 side to the +D1 side within the region enclosed by the first incident end 150a, the exit end 150b, and the first reflective surface 150r.

[0028] A portion of the green light LG incident on the leading light unit 150 is incident directly from the first incident end 150a to the exit end 150b along a direction that forms an angle smaller than a predetermined angle with respect to the first optical axis 150C, without being reflected even once by the first reflecting surface 150r. The remaining portion of the green light LG incident on the leading light unit 150 forms an angle greater than or equal to a predetermined angle with respect to the first optical axis 150C, is incident on the first incident end 150a to the first reflecting surface 150r one or more times, is reflected by the first reflecting surface 150r, and then reaches the exit end 150b. The path of the green light LG rays within the region enclosed by the first incident end 150a, the exit end 150b, and the first reflecting surface 150r differs depending on the angle of incidence to the first incident end 150a, and extends to multiple paths with different numbers of reflections at the first reflecting surface 150r. As a result, the illuminance distribution of the green light LG propagating in the region enclosed by the first incident end 150a, the exit end 150b, and the first reflective surface 150r is homogenized in a plane including the D2 and D3 directions. In other words, the leading light unit 150 homogenizes the illuminance distribution of the incident green light LG in a plane including the D2 and D3 directions. The green light LG with a homogenized illuminance distribution is emitted from the exit end 150b towards the +D1 side.

[0029] The first sub-light guide 151 has a second incident end 151a into which red light LR emitted from the red light source 12 is incident, a first confluence end 151b that emits the red light LR toward the -D2 side to merge it with the main light section 150, and a second side surface 151s and a second reflective surface 151r that extend between the second incident end 151a and the first confluence end 151b in the D2 direction. The first sub-light guide 151 has a second optical axis 151C that passes through the center of the second incident end 151a and the center of the first confluence end 151b. The second optical axis 151C of the first sub-light guide 151 is perpendicular to the first optical axis 150C of the main light section 150. The first sub-light guide 151 has a shape similar to the peripheral portion of the first incident end 150a of the main light section 150. Therefore, the first sub-light guide section 151 has a shape that overlaps with the main light section 150 when rotated 90 degrees clockwise around an axis along the D3 direction.

[0030] The second incident end 151a extends parallel to the plane including the D1 and D3 directions. The shape of the second incident end 151a when viewed from the D2 direction is similar to the shape of the light-emitting surface of the red light-emitting element 12b when viewed from the same direction, and is, for example, rectangular.

[0031] The second side surface 151s and the second reflective surface 151r connect the peripheral edge of the second incident end 151a and the peripheral edge of the first confluence end 151b in the D2 direction. The first confluence end 151b is connected to the first side surface 150s facing the +D2 side of the leading light section 150.

[0032] The red light LR emitted from the red light source 12 enters the first sub-light guide section 151 from the second incident end 151a. The first sub-light guide section 151 merges the red light LR guiding through its interior with the main light section 150. In the first sub-light guide section 151, the region enclosed by the second incident end 151a, the first confluence end 151b, and the second reflective surface 151r is the region through which the red light LR propagates. The size of the region enclosed by the second incident end 151a, the first confluence end 151b, and the second reflective surface 151r in the plane including the D1 and D3 directions increases as it progresses from the +D2 side to the -D2 side in the D2 direction.

[0033] The second side surface 151s of the first sub-light guide 151, and the second reflective surface 151r provided on the second side surface 151s as described later, form a predetermined angle with respect to the second optical axis 151C, and move away from the imaginary line in a plane including the D1 and D3 directions as it moves from the +D2 side to the -D2 side. The red light LR incident on the first sub-light guide 151 propagates from the +D2 side to the -D2 side within the region enclosed by the second incident end 151a, the first confluence end 151b, and the second reflective surface 151r.

[0034] The first sub-light guide section 151, like the main light section 150, is composed of a reflector made of a transparent material such as optical glass. The reflector has a frame and is a hollow optical element. When viewed along the D2 direction, the +D2 side end of the reflector frame has the same shape as the second incident end 151a and the light-emitting surface of the red light-emitting element 12b, and is formed to the same size as the light-emitting surface of the red light-emitting element 12b, for example, in the shape of a rectangular frame. The -D2 side end of the reflector frame has the same shape and size as the first confluence end 151b, and is formed to the same size as, for example, a rectangular frame, but different in size from the +D2 side end.

[0035] The first confluence end 151b is connected to a first side surface 150s that is inclined with respect to the planes along the D1 and D3 directions and faces the +D2 side. Therefore, the reflector of the first sub-light guide section 151 is composed of two rectangular plate-like members arranged in the D3 direction and two trapezoidal plate-like members arranged in the D1 direction. The two plate-like members arranged in the D3 direction have the same rectangular shape. On the other hand, the two plate-like members arranged in the D1 direction have trapezoidal shapes of different sizes, with the trapezoid on the -D1 side being larger than the trapezoid on the +D1 side.

[0036] In the leading light section 150 of this embodiment, the outer surfaces of the four plate-shaped members constitute the first side surface 150s, and the inner surfaces of the four plate-shaped members are provided with a reflective film 161 made of a dielectric multilayer film or the like, thereby functioning as the first reflective surface 150r. Light entering the reflector of the leading light section 150 from the first incident end 150a is reflected by the first reflective surface 150r made of the reflective film 161 and propagates toward the +D1 side.

[0037] In the first sub-light guide section 151 of this embodiment, the outer surfaces of the four plate-shaped members correspond to the second side surfaces 151s, and a reflective film 162 made of a dielectric multilayer film or the like is provided on the inner surfaces of the four plate-shaped members, thereby functioning as a second reflective surface 151r. A portion of the red light LR that enters the interior of the reflector of the first sub-light guide section 151 from the second incident end 151a is reflected by the second reflective surface 151r made of the reflective film 162, travels toward the -D2 side, and merges with the main light section 150. In addition, in the first sub-light guide section 151, a reflective film 162 may be formed on the plate surface of the plate-shaped member constituting the reflector that faces the external space, thereby acting as a second reflective surface 151r.

[0038] The light guide element 50 of this embodiment has a first selective transparent film (selective transparent film) 153 provided at the connection portion between the main light section 150 and the first sub-light guide section 151. More specifically, the first selective transparent film 153 is provided at the connection portion between the first sub-light guide section 151 and the first confluence end 151b of the plate-shaped member forming the first side surface 150s of the main light section 150. In this embodiment, the first selective transparent film 153 is provided on the inner surface of the plate-shaped member, and the inner surface on which the first selective transparent film 153 is provided has different optical properties from the first reflective surface 150r. The first selective transparent film 153 is composed of a dichroic film having optical properties that reflect green light LG and red light LR guided within the main light section 150, and selectively transmit red light LR guided within the first sub-light guide section 151. As a result, the first selective transparent film 153 can suppress leakage of green light LG, which is guided within the main light section 150, to the first sub-light guide section 151. In addition, the red light LR guided within the first sub-light guide section 151 is well guided into the main light section 150 by passing through the first selective transparent film 153 from the first confluence end 151b. Furthermore, during the process of guiding the red light LR within the first sub-light guide section 151, the illuminance distribution of the red light LR is more uniform than at the second incident end 151a.

[0039] A portion of the red light LR incident on the main light source 150 is incident on the first reflecting surface 150r one or more times, reflected by the first reflecting surface 150r, and then reaches the exit end 150b. In this way, the illuminance distribution of the red light LR propagating inside the first sub-light guide 151 and the main light source 150 is made uniform.

[0040] A portion of the red light LR incident on the main light unit 150 may be incident on the first selective transparent film 153. The first selective transparent film 153 in this embodiment has an incident angle dependence with respect to the red light LR. The first selective transparent film 153 transmits red light LR incident on the first selective transparent film 153 at an angle smaller than a predetermined angle, and reflects red light LR incident on the first selective transparent film 153 at an angle larger than a predetermined angle. With this configuration, the first selective transparent film 153 can function mainly as a transparent film for red light LR emitted from the red light source 12 and incident by being guided through the first sub-light guide unit 151, and can function as a reflective film for red light LR that merges into the main light unit 150, is reflected within the main light unit 150, and is then incident on the first selective transparent film 153 again. Therefore, it is possible to suppress the leakage of red light LR guiding through the main light unit 150 through the first selective transparent film 153 to the first sub-light guide unit 151 side. Therefore, red light LR can be efficiently extracted from the emission end 150b.

[0041] The second sub-light guide 152 has a third incident end 152a into which blue light LB emitted from the blue light source 13 is incident, a second confluence end 152b that emits the blue light LB toward the +D2 side to merge it with the main light section 150, and a third side surface 152s and a third reflective surface 152r that extend between the third incident end 152a and the second confluence end 152b in the D2 direction. The second sub-light guide 152 has a third optical axis 152C that passes through the center of the third incident end 152a and the center of the second confluence end 152b. The third optical axis 152C of the second sub-light guide 152 coincides with the second optical axis 151C of the first sub-light guide 151 and is perpendicular to the first optical axis 150C of the main light section 150. The second sub-light guide section 152 has a shape similar to that of the peripheral portion of the first incident end 150a of the main light section 150, just like the first sub-light guide section 151.

[0042] The third incident end 152a extends parallel to the plane including the D1 and D3 directions. The shape of the third incident end 152a when viewed from the D2 direction is similar to the shape of the light-emitting surface of the blue light-emitting element 13b when viewed from the same direction, and is, for example, rectangular.

[0043] The third side surface 152s and the third reflective surface 152r connect the peripheral edge of the third incident end 152a and the peripheral edge of the second confluence end 152b in the D2 direction. The second confluence end 152b is connected to the first side surface 150s facing the -D2 side of the leading light section 150.

[0044] The blue light LB emitted from the blue light source 13 enters the second sub-light guide section 152 from the third incident end 152a. The second sub-light guide section 152 merges the blue light LB guiding inside with the main light section 150. In the second sub-light guide section 152, the region enclosed by the third incident end 152a, the second confluence end 152b, and the third reflective surface 152r is the region through which the blue light LB propagates. The size of the region enclosed by the third incident end 152a, the second confluence end 152b, and the third reflective surface 152r in the plane including the D1 and D3 directions increases as it progresses from the -D2 side to the +D2 side in the D2 direction.

[0045] The third side surface 152s of the second sub-light guide 152, and the second reflective surface 151r provided on the third side surface 152s as described later, form a predetermined angle with respect to the third optical axis 152C, and move away from the imaginary line in a plane including the D1 and D3 directions as it moves from the -D2 side to the +D2 side. The blue light LB incident on the second sub-light guide 152 propagates from the -D2 side to the +D2 side within the region enclosed by the third incident end 152a, the second confluence end 152b, and the third reflective surface 152r.

[0046] The second sub-light guide section 152, like the first sub-light guide section 151, is composed of a reflector made of a transparent material such as optical glass. The reflector has a frame and is a hollow optical element. When viewed along the D2 direction, the -D2 end of the reflector's frame has the same shape as the third incident end 152a and the light-emitting surface of the blue light-emitting element 13b, and is formed to the same size as the light-emitting surface of the blue light-emitting element 13b, for example, in the shape of a rectangular frame. The +D2 end of the reflector's frame has the same shape and size as the second confluence end 152b, and is formed to the same size as, for example, a rectangular frame, but different in size from the -D2 end.

[0047] The second confluence end 152b is connected to a first side surface 150s that is inclined with respect to the planes along the D1 and D3 directions and faces the -D2 side. Therefore, the reflector of the second sub-light guide section 152 is composed of two rectangular plate-like members arranged in the D3 direction and two trapezoidal plate-like members arranged in the D1 direction. The two plate-like members arranged in the D3 direction have the same rectangular shape. On the other hand, the two plate-like members arranged in the D1 direction have trapezoidal shapes of different sizes, with the trapezoid on the -D1 side being larger than the trapezoid on the +D1 side.

[0048] In the second sub-light guide section 152 of this embodiment, the outer surfaces of the four plate-like members constitute the third side surface 152s, and the inner surfaces of the four plate-like members are provided with a reflective film 163 made of a dielectric multilayer film or the like, thereby functioning as a third reflective surface 152r. A portion of the blue light LB that enters the interior of the reflector of the second sub-light guide section 152 from the third incident end 152a is reflected by the third reflective surface 152r made of the reflective film 163, travels toward the +D2 side, and merges with the main light section 150. In addition, in the second sub-light guide section 152, a reflective film 163 may be formed on the plate surface of the plate-shaped member constituting the reflector that faces the external space, thereby acting as a third reflective surface 152r.

[0049] The light guide element 50 of this embodiment has a second selective transparent film 154 provided at the connection portion between the main light section 150 and the second sub-light guide section 152. More specifically, the second selective transparent film 154 is provided at the connection portion between the second sub-light guide section 152 and the second confluence end 152b of the plate-shaped member forming the first side surface 150s of the main light section 150. In this embodiment, the second selective transparent film 154 is provided on the inner surface of the plate-shaped member, and the inner surface on which the second selective transparent film 154 is provided has different optical properties from the first reflective surface 150r. The second selective transparent film 154 is composed of a dichroic film having optical properties that reflect blue light LB guided through the main light section 150 and transmit blue light LB guided through the second sub-light guide section 152. As a result, the second selective transparent film 154 can suppress leakage of green light LG, which is guided within the main light section 150, to the second sub-light guide section 152. In addition, the blue light LB guided within the second sub-light guide section 152 is well guided into the main light section 150 by passing through the second selective transparent film 154 from the second confluence end 152b. Furthermore, during the process of guiding the blue light LB within the second sub-light guide section 152, the illuminance distribution of the blue light LB is more uniform than at the third incident end 152a.

[0050] A portion of the blue light LB incident on the main light source 150 is incident on the first reflecting surface 150r one or more times, reflected by the first reflecting surface 150r, and then reaches the emission end 150b. In this way, the illuminance distribution of the blue light LB propagating inside the second sub-light guide 152 and the main light source 150 is made uniform.

[0051] A portion of the blue light LB incident on the main light unit 150 may also be incident on the second selective transparent film 154. The second selective transparent film 154 in this embodiment has an incident angle dependence with respect to the blue light LB. The second selective transparent film 154 transmits blue light LB incident on the second selective transparent film 154 at an angle smaller than a predetermined angle, and reflects blue light LB incident on the second selective transparent film 154 at an angle larger than a predetermined angle. With this configuration, the second selective transparent film 154 can function mainly as a transparent film for blue light LB emitted from the blue light source 13 and incident by being guided through the second sub-light guide unit 152, and can function as a reflective film for blue light LB that merges into the main light unit 150, is reflected within the main light unit 150, and is then incident on the second selective transparent film 154 again. Therefore, it is possible to suppress the leakage of blue light LB that is guided through the main light unit 150 through the second selective transparent film 154 to the second sub-light guide unit 152 side. Therefore, the blue light LB can be efficiently extracted from the emission end 150b.

[0052] The image forming module 1 of this embodiment drives the green light source 11, the red light source 12, and the blue light source 13 in sequential time. As a result, the green light source 11, the red light source 12, and the blue light source 13 emit green light LG, red light LR, and blue light LB in sequential time. In this way, the image forming module 1 of this embodiment emits green light LG, red light LR, and blue light LB as illumination light L from the emission end 150b of the light guide element 50 in sequential time.

[0053] The parallelizing element 16 is, for example, a plano-convex lens and is provided on the optical path of the illumination light L emitted from the light guide element 50. The parallelizing element 16 parallelizes the illumination light L emitted from the light guide element 50 along the D1 direction. The parallelizing element 16 is in contact with the exit end 150b of the light guide element 50. By the parallelizing element 16 being in contact with the exit end 150b, the illumination light L emitted from the exit end 150b of the light guide element 50 is efficiently captured by the parallelizing element 16, thereby suppressing light loss. However, the parallelizing element 16 may be an optical lens other than a plano-convex lens capable of parallelizing incident light. Also, the parallelizing element 16 may be arranged at an appropriate distance from the light guide element 50 in the D1 direction.

[0054] The optical modulation device 20 modulates the illumination light L, which consists of a parallel light beam emitted from the parallelizing element 16, according to the image information. The optical modulation device 20 includes an optical modulation element 21, an incident polarizing element 22, and an exit polarizing element 23.

[0055] The incident polarizing element 22 is provided on the optical path of the illumination light L emitted from the parallelizing element 16 and is positioned on the +D1 side of the parallelizing element 16. In this embodiment, the incident polarizing element 22 is in contact with the optical modulation element 21 from the -D1 side, but it may also be positioned at an appropriate distance from the optical modulation element 21 in the D1 direction.

[0056] The incident polarizing element 22 emits a predetermined polarization of the illumination light L emitted from the parallelizing element 16 along the D1 direction towards the +D1 side. The predetermined polarization is, for example, S polarization. The incident polarizing element 22 is, for example, a reflective polarizer having a plate surface parallel to the planes including the D2 and D3 directions. The incident polarizing element 22 transmits a portion of the incident illumination light L, including the predetermined polarization, to the +D1 side and reflects the other portion of the incident illumination light L to the -D1 side.

[0057] The optical modulation element 21 is located on the optical path of the illumination light L emitted from the incident polarizing element 22, and is positioned on the +D1 side of the incident polarizing element 22. The optical modulation element 21 modulates the illumination light L emitted from the incident polarizing element 22 based on image information transmitted from an image forming apparatus, such as a computer (not shown), which is connected to the optical modulation element 21 from the outside.

[0058] The optical modulation element 21 is, for example, a transmissive liquid crystal panel. The liquid crystal panel constituting the optical modulation element 21 has a plurality of pixels (not shown). Each pixel is equipped with a switching element. The optical modulation element 21 modulates and generates image light IM of a color corresponding to the light incident as illumination light L. The optical modulation element 21 emits the image light IM generated by the liquid crystal panel along the D1 direction toward the +D1 side.

[0059] The ejection-side polarizing element 23 is provided on the optical path of the image light IM emitted from the optical modulation element 21 and is positioned on the +D1 side of the optical modulation element 21. In this embodiment, the ejection-side polarizing element 23 is, for example, in contact with the optical modulation element 21 from the +D1 side, but it may also be positioned at an appropriate distance from the optical modulation element 21 in the D1 direction. The ejection-side polarizing element 23 emits a predetermined polarization of the image light IM emitted from the optical modulation element 21 along the D1 direction toward the +D1 side. The predetermined polarization is, for example, S polarization.

[0060] The exit-side polarizing element 23 is, for example, a reflective polarizer or an absorbing polarizer having a plate surface parallel to the planes including the D2 and D3 directions. The exit-side polarizing element 23 transmits a predetermined polarization of the incident image light IM to the +D1 side and reflects or absorbs other polarizations of the image light IM. By using an absorbing polarizer as the exit-side polarizing element 23, reflected light and stray light to the optical modulation element 21 can be suppressed.

[0061] In this way, the image forming module 1 can emit blue, green, or red image light IM in a time-resolved manner. The projection optical system 5 is positioned on the optical path of the image light IM emitted from the image forming module 1. The projection optical system 5 projects the image light IM onto the screen SCR, which is located +D2 side of the projection optical system 5, and displays the image light IM on the screen SCR in an enlarged manner.

[0062] The projection optical system 5 is composed of, for example, one or more optical lenses arranged along the D2 direction. The optical lenses include, for example, plano-convex lenses, plano-concave lenses, biconvex lenses, biconcave lenses, meniscus lenses, aspherical lenses, free-form lenses, and the like.

[0063] As described above, the image forming module 1 of this embodiment includes a green light source 11 that emits green light LG, a red light source 12 that emits red light LR, a blue light source 13 that emits blue light LB, a light guide element 50 that guides the green light LG emitted from the green light source 11, the red light LR emitted from the red light source 12, and the blue light LB emitted from the blue light source 13 internally and emits the green light LG, red light LR, and blue light LB from a single emission end 150b, and a light modulation device 20 that modulates each color of light emitted from the light guide element 50 according to image information. The light guide element 50 includes a leading light section 150 that includes a first input end 150a into which green light LG emitted from the green light source 11 is incident and guides the green light LG to the output end 150b; a first sub-light guide section 151 that includes a second input end 151a into which red light LR emitted from the red light source 12 is incident and merges the red light LR with the leading light section 150; and a second sub-light guide section 152 that merges the blue light LB with the leading light section 150.

[0064] According to the image forming module 1 of this embodiment, the light guide element 50 that guides the LR, LG, and LB light of each color incident from each light source 11, 12, and 13 and emits it from the exit end 150b toward the optical modulator 20 can be made of a single optical component. Therefore, since there is only one light guide element and a combining prism that combines the light from each light guide element is not required, the image forming module 1 can be made smaller compared to conventional configurations that use multiple light guide elements. Furthermore, since the image forming module 1 of this embodiment employs a single-chip system using one optical modulator 20, the device configuration can be made smaller compared to a so-called three-chip system.

[0065] Furthermore, in the image forming module 1 of this embodiment, each color light LR, LG, and LB is incident on the optical modulator 20 from the emission end 150b of the main light unit 150, so that each color light LR, LG, and LB can be incident on the optical modulator 20 efficiently.

[0066] Furthermore, the projector 100 of this embodiment includes an image forming module 1 and a projection optical system 5 that projects image light IM emitted from the image forming module 1. Therefore, according to the projector 100 of this embodiment, since it is equipped with a small image forming module 1, it is possible to provide a projector that is compact yet projects bright images.

[0067] (modified version) Next, a modified example of the image forming module 1 of the first embodiment will be described. Figure 3 shows the main components of the image forming module 1A in this modified example. As shown in Figure 3, the modified image forming module 1A further includes a polarization conversion member 17. The polarization conversion member 17 is positioned between the light guide element 50 and the parallelizing element 16, specifically between the exit end 150b of the light guide element 50 and the parallelizing element 16.

[0068] The polarization conversion member 17 is a member that converts the polarization direction of each color light LR, LG, LB emitted from the emission end 150b of the light guide element 50 to a predetermined polarization direction. The polarization conversion member 17 converts each color light LR, LG, LB into linearly polarized light with aligned polarization directions. Although not shown in the figure, the polarization conversion member 17 consists of a polarization separation film made of a dielectric multilayer film positioned at approximately 45° with respect to the incident light, and a waveplate that rotates one of the separated polarizations by half a wavelength.

[0069] The polarization conversion member 17 converts the polarization direction of each color light LR, LG, LB into S-polarized light that passes through the incident polarizing element 22 of the optical modulator 20. By providing such a polarization conversion member 17, the colors LR, LG, LB emitted from the exit end 150b of the light guide element 50 can be aligned to S-polarized light. Therefore, each color light LR, LG, LB can pass through the incident polarizing element 22 and be efficiently incident on the optical modulator 21. Thus, the colors LR, LG, LB emitted from each light source 11, 12, 13 can be efficiently used to generate image light, and the light utilization efficiency of the image forming module 1A can be improved.

[0070] Furthermore, if the polarization conversion member 17 is provided, S-polarized light can be incident on the optical modulation device 20, so the incident polarizing element 22 may be omitted if necessary. Alternatively, instead of using the polarization separation film and waveplate as described above, the polarization conversion member 17 may be made of a reflective polarizer similar to the incident polarizer 22. In this case, the polarization conversion member 17 and the incident polarizer 22 may be made of a single reflective polarizer. Furthermore, the position where the polarization conversion member 17 is placed is not limited to the emission end 150b of the light guide element 50; for example, it may be placed anywhere along the optical path before the respective color lights LR, LG, and LB reach the emission end 150b.

[0071] (Second Embodiment) Next, the image forming module of the second embodiment will be described. The difference between this embodiment and the first embodiment lies in the configuration of the light guide element; all other configurations are the same. Therefore, the configuration of the light guide element will be described below, and the same reference numerals will be used for components and parts as in the first embodiment, and detailed explanations will be omitted.

[0072] Figure 4 is a perspective view showing the main components of the light guide element 51 of this embodiment. As shown in Figure 4, the light guide element 51 has a main light section 250, a first sub-light guide section 251, and a second sub-light guide section 252.

[0073] The light guide element 51 of this embodiment is a solid optical element formed by joining together a plurality of prism members 200 made of a transparent material such as optical glass. Furthermore, an optical film 201 is provided on the joining surface of each prism member 200 constituting the light guide element 51. In other words, the light guide element 51 of this embodiment includes a plurality of prism members 200 and a plurality of optical films 201 arranged on the joining surfaces of the plurality of prism members 200.

[0074] Figure 5 is a cross-sectional view of the light guide element 51, including the D1 and D2 directions. As shown in Figure 5, the light guide element 51 of this embodiment is constructed by joining six prism members 200. The leading light section 250 is constructed by joining four prism members 200. In the following description, the four prism members 200 constituting the leading light section 250 will be referred to as the first prism member 211, the second prism member 212, the third prism member 213, and the fourth prism member 214, respectively.

[0075] The leading light section 250 has a first incident end 250a, an exit end 250b, a first side surface 250s, and a first reflective surface 250r. In the leading light section 250 of this embodiment, the outer surface of the prism member 200 corresponds to the first side surface 250s, and the first side surface 250s functions as a first reflective surface 250r that totally reflects light propagating inside the leading light section 250. Alternatively, a mirror made of metal may be provided on the first side surface 250s to function as the first reflective surface 250r.

[0076] Inside the main light section 250, a first light guide path LT1, a second light guide path LT2, and a third light guide path LT3 are formed. The first light guide path LT1 is the part that guides the green light LG incident from the first incident end 150a toward the exit end 150b. The second light guide path LT2 is the part that guides the red light LR that merges into the main light section 250 from the first sub-light guide section 251 toward the exit end 150b. The third light guide path LT3 is the part that guides the blue light LB that merges into the main light section 250 from the second sub-light guide section 252 toward the exit end 150b. These first light guide path LT1, second light guide path LT2, and third light guide path LT3 are formed by a plurality of prism members 200 and a plurality of optical films 201.

[0077] The first sub-light guide section 251 is composed of a single prism member 200. The first sub-light guide section 251 has a second incident end 251a, a first confluence end 251b, a second side surface 251s, and a second reflective surface 251r. In the first sub-light guide section 251 of this embodiment, the outer surface of the prism member 200 corresponds to the second side surface 251s, and the second side surface 251s functions as a second reflective surface 251r that totally reflects light propagating inside the first sub-light guide section 251. Alternatively, a reflective film made of a dielectric multilayer film or the like may be provided on the second side surface 251s to make it function as a second reflective surface 251r.

[0078] The second sub-light guide section 252 is composed of a single prism member 200. The second sub-light guide section 252 has a third incident end 252a, a second confluence end 252b, a third side surface 252s, and a third reflective surface 252r. In the second sub-light guide section 252 of this embodiment, the outer surface of the prism member 200 corresponds to the third side surface 252s, and the third side surface 252s functions as a third reflective surface 252r that totally reflects light propagating inside the second sub-light guide section 252.

[0079] The light guide element 51 of this embodiment includes a first selective transparent film (selective transparent film) 253, a second selective transparent film 254, a first incident-side reflective film (first reflective film) 255, and a second incident-side reflective film 256. In the light guide element 51 of this embodiment, among the multiple optical films 201, the optical film 201 provided on the junction surface between the second prism member 212 of the main light section 250 and the prism member 200 constituting the first sub-light guide section 251 functions as the first selective transparent film 253. The first selective transparent film 253 reflects the green light LG guided within the main light section 250. Therefore, together with the multiple prism members 200, the first selective transparent film 253 can form a first light guide path LT1 that guides the green light LG guided within the main light section 250 to the first sub-light guide section 251 side while suppressing leakage of the green light LG to the exit end 250b.

[0080] The first selective transparent film 253 selectively transmits the red light LR guided through the first sub-light guide section 251 and merges it into the main light section 250. Similar to the first embodiment, the first selective transparent film 253 of this embodiment has an incident angle dependence with respect to the red light LR. Therefore, the first selective transparent film 253 functions as a transparent film for the red light LR incident from the first sub-light guide section 251 and as a reflective film for the red light LR guided through the main light section 150.

[0081] Furthermore, in the light guide element 51 of this embodiment, among the multiple optical films 201, the optical film 201 provided on the junction surface between the third prism member 213 of the main light section 250 and the prism member 200 constituting the second sub-light guide section 252 functions as the second selective transparent film 254. The second selective transparent film 254 reflects the green light LG guided within the main light section 250. Therefore, together with the multiple prism members 200, the second selective transparent film 254 can form a first light guide path LT1 that guides the green light LG guided within the main light section 250 to the second sub-light guide section 252 side while suppressing leakage of the green light LG to the exit end 250b.

[0082] The second selective transparent film 254 selectively transmits the blue light LB guided through the second sub-light guide section 252 and merges it into the main light section 250. Similar to the first embodiment, the second selective transparent film 254 in this embodiment has an incident angle dependence with respect to the blue light LB. Therefore, the second selective transparent film 254 functions as a transparent film for blue light LB incident from the second sub-light guide section 252 and as a reflective film for blue light LB guided through the main light section 150.

[0083] The second light guide path LT2 of the light guide element 51 in this embodiment is formed by a second prism member 212, a fourth prism member 214, and a first incident-side reflective film 255. The first incident-side reflective film 255 is composed of optical films 201 provided on the joint surface between the first prism member 211 and the second prism member 212, and on the joint surface between the third prism member 213 and the fourth prism member 214, among a plurality of optical films 201. The first incident-side reflective film 255 reflects the component of red light LR that is directed toward the first incident end 250a side of the red light LR incident from the first sub-light guide section 251 to the main light section 250. This suppresses the occurrence of problems such as the inability to efficiently extract red light LR emitted toward the first incident end 250a side opposite to the exit end 250b from the exit end 250b. Furthermore, the optical loss of red light LR due to direct leakage from the first incident end 250a to the outside of the leading light section 250 is suppressed, and the red light LR can be efficiently extracted from the exit end 250b.

[0084] Furthermore, the third light guide path LT3 of the light guide element 51 in this embodiment is formed by a third prism member 213, a fourth prism member 214, and a second incident-side reflective film 256. The second incident-side reflective film 256 is composed of optical films 201 provided on the joint surface between the first prism member 211 and the third prism member 213, and on the joint surface between the second prism member 212 and the fourth prism member 214, among a plurality of optical films 201. The second incident-side reflective film 256 reflects the component of the blue light LB that is incident on the main light unit 250 from the second sub-light guide unit 252 and is directed toward the first incident end 250a. This suppresses the occurrence of problems such as the inability to efficiently extract the blue light LB emitted toward the first incident end 250a, opposite to the exit end 250b, from the exit end 250b. Furthermore, the optical loss of blue light LB due to direct leakage from the first incident end 250a to the outside of the leading light section 250 is suppressed, and the blue light LB can be efficiently extracted from the exit end 250b.

[0085] On the other hand, the first incident-side reflective film 255 is positioned in part of the first light guide path LT1 and part of the third light guide path LT3. The first incident-side reflective film 255 is composed of a dichroic film that reflects red light LR and transmits green light LG and blue light LB. Therefore, the first incident-side reflective film 255 can guide the green light LG and blue light LB that are guided through the first light guide path LT1 and the third light guide path LT3 to the exit end 250b without blocking them. Furthermore, the second incident-side reflective film 256 is positioned in a portion of the first light guide path LT1 and a portion of the second light guide path LT2. The second incident-side reflective film 256 is composed of a dichroic film that reflects blue light LB and transmits green light LG and red light LR. Therefore, the second incident-side reflective film 256 can guide the green light LG and red light LR that are guided through the first light guide path LT1 and the second light guide path LT2 to the exit end 250b without blocking them.

[0086] In this embodiment, the light guide element 51 can reflect the component of the red light LR that is directed toward the first incident end 250a side of the red light LR that is merged into the main light section 250 by the first sub-light guide section 251 toward the emission end 150b side by the first incident side reflective film 255. A portion of the red light LR reflected by the first incident side reflective film 255 is reflected at least once within the main light section 250 and emitted from the emission end 250b. As a result, the light guide element 51 of this embodiment can further improve the uniformity of the in-plane illuminance of the red light LR emitted from the emission end 250b compared to the light guide element 51 of the first embodiment.

[0087] Furthermore, the light guide element 51 of this embodiment can reflect the component of the blue light LB that is directed toward the first incident end 250a side of the blue light LB that is merged into the main light section 250 by the second sub-light guide section 252 toward the emission end 150b side by the second incident side reflective film 256. A portion of the blue light LB reflected by the second incident side reflective film 256 is reflected at least once within the main light section 250 and emitted from the emission end 250b. As a result, the light guide element 51 of this embodiment can further improve the uniformity of the in-plane illuminance of the blue light LB emitted from the emission end 250b compared to the light guide element 51 of the first embodiment. Furthermore, the green light LG is guided within the main light source 250, ensuring sufficient uniformity of in-plane illuminance before being emitted from the emission end 250b. In contrast, the red light LR and blue light LB, which join the main light source 250 midway, may exhibit reduced uniformity of in-plane illuminance compared to the green light LG.

[0088] In contrast, the light guide element 51 of this embodiment enhances the uniformity of the in-plane illuminance of the red light LR and blue light LB emitted from the emission end 250b by the first incident side reflective film 255 and the second incident side reflective film 256, as described above, thereby bringing the in-plane illuminance of the red light LR and blue light LB closer to that of the green light LG. Therefore, the light guide element 51 of this embodiment allows each color light LR, LG, and LB, which have small differences in the uniformity of in-plane illuminance, to be emitted from the emission end 250b. Consequently, the image forming module using the light guide element 51 of this embodiment can generate high-quality image light with reduced color unevenness. Therefore, the projector of this embodiment can provide a projector that is compact yet projects bright, high-quality images without color unevenness.

[0089] (Third embodiment) Next, the image forming module of the third embodiment will be described. The difference between this embodiment and the second embodiment lies in the configuration of the leading light portion of the light guide element; all other configurations are the same. Therefore, the following description will mainly focus on the configuration of the leading light portion of the light guide element, and components and parts similar to those in the second embodiment will be denoted by the same reference numerals, with detailed explanations omitted.

[0090] Figure 6 is a cross-sectional view of the light guide element 52 of this embodiment, including the D1 and D2 directions. As shown in Figure 6, the light guide element 52 of this embodiment has a main light section 260, a first sub-light guide section 261, and a second sub-light guide section 262. The light guide element 52 in this embodiment is constructed by joining 11 prism members 210. The main light section 260 is constructed by joining 9 prism members 210. The first sub-light guide section 261 and the second sub-light guide section 262 are each composed of one prism member 210. In the following description, the nine prism members 210 constituting the leading light section 260 will be referred to as the first prism member 221, the second prism member 222, the third prism member 223, the fourth prism member 224, the fifth prism member 225, the sixth prism member 226, the seventh prism member 227, the eighth prism member 228, and the ninth prism member 229, respectively.

[0091] The leading light section 260 has a first incident end 260a, an exit end 260b, a first side surface 260s, and a first reflective surface 260r. In the leading light section 260 of this embodiment, the outer surface of the prism member 210 corresponds to the first side surface 260s, and the first side surface 260s functions as a first reflective surface 260r that totally reflects light propagating inside the leading light section 260. Alternatively, a mirror made of metal may be provided on the first side surface 260s to function as the first reflective surface 260r.

[0092] Inside the leading light section 260, a first light guide path LT1, a second light guide path LT2, and a third light guide path LT3 are formed. These first light guide path LT1, second light guide path LT2, and third light guide path LT3 are formed by a plurality of prism members 210 and a plurality of optical films 202.

[0093] The light guide element 52 of this embodiment includes a first selective transparent film 263, a second selective transparent film 264, a first incident-side reflective film (first reflective film) 265, a second incident-side reflective film 266, a first exit-side reflective film (second reflective film) 267, and a second exit-side reflective film 268.

[0094] In the light guide element 52 of this embodiment, among the multiple optical films 202, the optical film 202 provided at the junction surface between the second prism member 222 of the main light section 260 and the prism member 210 constituting the first sub-light guide section 261 functions as the first selective transmission film 263. The red light LR guided within the first sub-light guide section 261 is passed through the first selective transmission film 263 from the first confluence end 261b and is well guided into the main light section 260. In this way, the first selective transparent film 263, together with the multiple prism members 210, can form a first light guide path LT1 that guides the green light LG guiding within the main light section 260 to the first sub-light guide section 261 side, while suppressing leakage of the green light LG to the first sub-light guide section 261 side, and directs it to the exit end 260b.

[0095] Furthermore, in the light guide element 52 of this embodiment, among the multiple optical films 202, the optical film 201 provided at the junction surface between the third prism member 223 of the main light section 260 and the prism member 210 constituting the second sub-light guide section 262 functions as the second selective transmission film 264. The blue light LB guided within the second sub-light guide section 262 is effectively guided into the main light section 260 by passing through the second selective transmission film 264 from the second confluence end 262b. In this way, the second selective transparent film 264, together with the multiple prism members 210, can form a first light guide path LT1 that guides the blue light LB guiding within the main light section 260 to the second sub-light guide section 262 side, while suppressing leakage of the blue light LB to the exit end 260b.

[0096] The second light guide path LT2 of the light guide element 52 in this embodiment is formed by a second prism member 222, a fourth prism member 224, a fifth prism member 225, a sixth prism member 226, an eighth prism member 228, a ninth prism member 229, a first incident-side reflective film 265, and a first exit-side reflective film 267.

[0097] The first incident-side reflective film 265 is composed of optical films 202 provided on the joint surfaces of the first prism member 221 and the second prism member 222, the joint surfaces of the third prism member 223 and the fourth prism member 224, and the joint surfaces of the seventh prism member 227 and the eighth prism member 228, among a plurality of optical films 201. The first incident-side reflective film 265 reflects the component of the red light LR incident from the first sub-light guide 261 to the main light unit 260 that is directed toward the first incident end 260a. This suppresses the optical loss of red light LR due to direct leakage from the first incident end 260a to the outside of the main light unit 260, and allows the red light LR to be efficiently extracted from the exit end 260b.

[0098] The first exit-side reflective film 267 is composed of optical films 202 provided on the joint surfaces of the second prism member 222 and the fifth prism member 225, the joint surfaces of the fourth prism member 224 and the sixth prism member 226, and the joint surfaces of the eighth prism member 228 and the ninth prism member 229, among a plurality of optical films 201. The first exit-side reflective film 267 reflects the component of the red light LR that is incident on the exit end 260b from the first sub-light guide 261 to the main light unit 260. This suppresses the red light LR from being emitted outward from the exit end 260b without being reflected even once inside the main light unit 260, and by reflecting the red light LR multiple times inside the main light unit 260, the in-plane illuminance of the red light LR emitted from the exit end 260b can be made uniform.

[0099] The first exit-side reflective film 267 has an incident angle dependence with respect to red light LR. The first exit-side reflective film 267 transmits red light LR incident at an angle smaller than a predetermined angle to the first exit-side reflective film 267, and reflects red light LR incident at an angle larger than a predetermined angle to the first exit-side reflective film 267.

[0100] In this configuration, the first emission-side reflective film 267 primarily functions as a reflective film for red light LR incident at a large incident angle from within the first sub-light guide unit 261, and primarily functions as a transparent film for red light LR incident at a small incident angle to the first emission-side reflective film 267 by being emitted from within the first sub-light guide unit 261 and reflected by the first incident-side reflective film 265. As a result, the first emission-side reflective film 267 suppresses the direct emission of red light LR that has merged from the first sub-light guide unit 261 into the main light unit 260 from the emission end 260b, and allows red light LR that has been reflected at least once within the main light unit 260 to be emitted from the emission end 260b.

[0101] Furthermore, the first exit-side reflective film 267 also exhibits an incident angle dependence with respect to green light LG. The first exit-side reflective film 267 transmits green light LG incident at an angle smaller than a predetermined angle to the first exit-side reflective film 267, and reflects green light LG incident at an angle larger than a predetermined angle to the first exit-side reflective film 267.

[0102] With this configuration, the first emission-side reflective film 267 appropriately reflects the green light LG that guides light within the leading light section 260, thereby improving the uniformity of the illuminance of the green light LG and allowing it to be emitted from the emission end 260b. Furthermore, the first exit-side reflective film 267 has optical properties that allow blue light LB to pass through regardless of the angle of incidence.

[0103] Furthermore, the third light guide path LT3 of the light guide element 52 in this embodiment is formed by the third prism member 223, the fourth prism member 224, the sixth prism member 226, the seventh prism member 227, the eighth prism member 228, the ninth prism member 229, the second incident-side reflective film 266, and the second exit-side reflective film 268.

[0104] The second incident-side reflective film 266 is composed of optical films 202 provided on the joint surfaces of the first prism member 221 and the third prism member 223, the joint surfaces of the second prism member 222 and the fourth prism member 224, and the joint surfaces of the fifth prism member 225 and the sixth prism member 226, among a plurality of optical films 201. The second incident-side reflective film 266 reflects the component of the blue light LB that is incident on the leading light unit 260 from the second sub-light guide unit 262 toward the first incident end 260a. This suppresses the optical loss of blue light LB due to direct leakage from the first incident end 260a to the outside of the leading light unit 260, and allows the blue light LB to be efficiently extracted from the exit end 260b.

[0105] The second emission-side reflective film 268 is composed of optical films 202 provided on the joint surfaces of the third prism member 223 and the seventh prism member 227, the joint surfaces of the fourth prism member 224 and the eighth prism member 228, and the joint surfaces of the sixth prism member 226 and the ninth prism member 229, among a plurality of optical films 201. The second emission-side reflective film 268 reflects the component of the blue light LB that is incident on the emission end 260b from the second sub-light guide 262 to the main light unit 260. This suppresses the blue light LB from being emitted outward from the emission end 260b without being reflected even once inside the main light unit 260, and makes the in-plane illuminance of the blue light LB emitted from the emission end 260b uniform by reflecting the blue light LB multiple times inside the main light unit 260.

[0106] The second exit-side reflective film 268 has an incident angle dependence with respect to blue light LB. The second exit-side reflective film 268 transmits blue light LB incident at an angle smaller than a predetermined angle to the second exit-side reflective film 268, and reflects blue light LB incident at an angle larger than a predetermined angle to the second exit-side reflective film 268.

[0107] With this configuration, the second emission-side reflective film 268 primarily functions as a reflective film for blue light LB incident at a large incidence angle from within the second sub-light guide section 262, and primarily functions as a transparent film for blue light LB incident at a small incidence angle to the second emission-side reflective film 268 by being emitted from within the second sub-light guide section 262 and reflected by the second incidence-side reflective film 266. As a result, the second emission-side reflective film 268 suppresses the direct emission of blue light LB that has merged from the second sub-light guide section 262 into the main light section 260, and allows blue light LB that has been reflected at least once within the main light section 260 to be emitted from the emission end 260b.

[0108] Furthermore, the second exit-side reflective film 268 also exhibits an incident angle dependence with respect to green light LG. The second exit-side reflective film 268 transmits green light LG incident at an angle smaller than a predetermined angle to the second exit-side reflective film 268, and reflects green light LG incident at an angle larger than a predetermined angle to the second exit-side reflective film 268.

[0109] With this configuration, the second emission-side reflective film 268 appropriately reflects the green light LG that guides light within the leading light section 260, thereby improving the uniformity of the illuminance of the green light LG and allowing it to be emitted from the emission end 260b. Furthermore, the second exit-side reflective film 268 has optical properties that allow red light LR to pass through regardless of the angle of incidence.

[0110] Thus, in this embodiment, the light guide element 52 reflects red light LR by the first incident side reflective film 265 as well as the first exit side reflective film 267. As a result, a portion of the red light LR reflected by the first exit side reflective film 267 is reflected at least once within the main light portion 260 and then emitted from the exit end 260b. Furthermore, in this embodiment, the light guide element 52 reflects blue light LB not only with the second incident side reflective film 266 but also with the second exit side reflective film 268. As a result, a portion of the blue light LB reflected by the second exit side reflective film 268 is reflected at least once within the main light portion 260 and then emitted from the exit end 260b. As a result, the light guide element 52 of this embodiment can further improve the uniformity of the in-plane illuminance of the red light LR and blue light LB emitted from the emission end 260b compared to the light guide element 51 of the second embodiment. Therefore, the light guide element 52 of this embodiment brings the in-plane illuminance of the red light LR and blue light LB closer to the in-plane illuminance of the green light LG, thereby enabling the emission of each color light LR, LG, and LB from the emission end 260b, where the difference in uniformity of in-plane illuminance is small. Consequently, the image forming module using the light guide element 52 of this embodiment can generate higher quality image light with reduced color unevenness. Therefore, the projector of this embodiment can provide a projector that is compact yet projects bright, high-quality images without color unevenness.

[0111] (Fourth Embodiment) Next, the image forming module of the fourth embodiment will be described. The difference between this embodiment and the third embodiment lies in the configuration of the leading light portion of the light guide element; all other configurations are the same. Therefore, the following description will mainly focus on the configuration of the leading light portion of the light guide element, and components and parts similar to those of the third embodiment will be denoted by the same reference numerals, with detailed explanations omitted.

[0112] In the third embodiment of the light guide element 52, when bringing the uniformity of the in-plane illuminance of the red light LR and blue light LB closer to that of the green light LG, the red light LR or blue light LB was reflected in the plane including the D1 and D2 directions within the second light guide path LT2 and the third light guide path LT3. In this case, the uniformity of the in-plane illuminance of the red light LR and blue light LB emitted from the emission end 260b approaches that of the green light LG in the D2 direction, but in the D3 direction perpendicular to the D2 direction, the uniformity of the in-plane illuminance of the red light LR and blue light LB was lower than that of the green light LG. In contrast, the light guide element of this embodiment reflects red light LR or blue light LB sufficiently within the plane including the D1 and D3 directions in the second light guide path LT2 and the third light guide path LT3, thereby bringing the uniformity of the in-plane illuminance of red light LR and blue light LB in the D3 direction closer to the uniformity of the in-plane illuminance of green light LG.

[0113] The cross-sectional structure of the light guide element in this embodiment, including the planes in the D1 and D2 directions, is the same as that of the light guide element 52 in the third embodiment shown in Figure 6, so a description is omitted. Figure 7 is a cross-sectional view of the light guide element 53 of this embodiment, including the D2 and D3 directions. Figure 7 is a cross-sectional view including the second optical axis of the first sub-light guide and the third optical axis of the second sub-light guide. In the following description, the D2 direction may be referred to as the left-right direction, the +D3 side of the D3 direction as up, and the -D3 side as down. The D3 direction of this embodiment corresponds to the "direction perpendicular to the first optical axis and the second optical axis" of the present invention.

[0114] As shown in Figure 7, the light guide element 53 of this embodiment has a main light section 350, a first sub-light guide section 351, and a second sub-light guide section 352. The light guide element 53 of this embodiment is constructed by joining together a larger number of prism members 230 than the light guide element 52 of the third embodiment. Inside the leading light section 350, a first light guide path LT1, a second light guide path LT2, and a third light guide path LT3 are formed. These first light guide path LT1, second light guide path LT2, and third light guide path LT3 are formed by a plurality of prism members 230 and a plurality of optical films 203.

[0115] The light guide element 53 of this embodiment has a first upper and lower reflective film (third reflective film) 361 and a second upper and lower reflective film 362. In the cross-section shown in Figure 7, the six prism members 230 constituting the leading light section 350 are referred to as the first prism member 231, the second prism member 232, the third prism member 233, the fourth prism member 234, the fifth prism member 235, and the sixth prism member 236, respectively.

[0116] In the light guide element 53 of this embodiment, among the multiple optical films 203, the optical film 203 provided on the bonding surface between the first prism member 231 of the main light section 350 and the prism member 230 constituting the first sub-light guide section 351 functions as the first selective transmission film 363. In addition, among the multiple optical films 203, the optical film 203 provided on the bonding surface between the fourth prism member 234 of the main light section 350 and the prism member 230 constituting the second sub-light guide section 352 functions as the second selective transmission film 364.

[0117] The first upper and lower reflective film 361 is composed of a pair of optical films 202 provided on the joint surface between the first prism member 231 and the second prism member 232 and the joint surface between the first prism member 231 and the third prism member 233 in a portion of the second light guide path LT2. The first upper and lower reflective film 361 is composed of a dichroic film having optical properties that reflect red light LR and transmit green light LG and blue light LB.

[0118] The first upper and lower reflective film 361 reflects the component of red light LR incident from the first sub-light guide 351 to the main light section 350 that is directed in the vertical direction. The first upper and lower reflective film 361 is provided so as to expand in a tapered shape along the second side surface 351s in the vertical direction (D3 direction) of the first sub-light guide 351. In other words, the first upper and lower reflective film 361 is provided continuously with the second side surface 351s of the first sub-light guide 351. The red light LR guided within the first sub-light guide 351 behaves in the same way as when guided within the first sub-light guide 351 even after joining the second light guide path LT2 of the main light section 350. The first sub-light guide 351 has a shape similar to the peripheral part of the incident end of the main light section 350. This configuration can be considered equivalent to extending the distance over which the red light LR is guided within the main light section 350 in the vertical direction. Therefore, the behavior of the red light LR in the vertical direction can be considered equivalent to the behavior of the green light LG propagating within the main light unit 350. Consequently, the first vertical reflective film 361 makes it possible to reduce the difference in the vertical direction between the in-plane illuminance of the green light LG guiding the first light guide path LT1 and the in-plane illuminance of the red light LR guiding the second light guide path LT2.

[0119] The second upper and lower reflective film 362 is composed of a pair of optical films 202 provided on the joint surfaces of the fourth prism member 234 and the fifth prism member 235 and the joint surfaces of the fourth prism member 234 and the sixth prism member 236 in a portion of the third light guide path LT3. The second upper and lower reflective film 362 is composed of a dichroic film having optical properties that reflect blue light LB and transmit green light LG and red light LR.

[0120] The second upper and lower reflective film 362 reflects the vertical component of the blue light LB incident on the main light unit 350 from the second sub-light guide unit 352. The second upper and lower reflective film 362 is provided so as to expand in a tapered shape along the second side surface 352s in the vertical direction (D3 direction) of the second sub-light guide unit 352. In other words, the second upper and lower reflective film 362 is provided continuously with the second side surface 352s of the second sub-light guide unit 352. The blue light LB guided within the second sub-light guide unit 352 behaves in the same way as when guided within the second sub-light guide unit 352, even after merging with the third light guide path LT3 of the main light unit 350. The second sub-light guide unit 352 has a shape similar to the peripheral part of the incident end of the main light unit 350. This configuration can be considered equivalent to extending the distance over which the blue light LB is guided within the main light unit 350 in the vertical direction. Therefore, the behavior of the blue light LB in the vertical direction can be considered equivalent to the behavior of the green light LG propagating within the main light source 350. Consequently, the second vertical reflective film 362 makes it possible to reduce the difference in the vertical direction between the in-plane illuminance of the green light LG guiding the first light guide path LT1 and the in-plane illuminance of the red light LR guiding the third light guide path LT3.

[0121] Thus, the light guide element 53 of this embodiment reflects red light LR and blue light LB in the vertical direction as well as the left-right direction along the D2 direction using the first vertical reflective film 361 and the second vertical reflective film 362, respectively. As a result, it is possible to emit red light LR and blue light LB from the emission end 350b with a reduced difference in in-plane illuminance relative to green light LG in both the vertical and left-right directions.

[0122] According to the light guide element 53 of this embodiment, each color light LR, LG, and LB with small differences in in-plane illuminance uniformity can be emitted from the emission end 350b. Therefore, the image forming module using the light guide element 53 of this embodiment can generate higher quality image light with reduced color unevenness. Thus, the projector of this embodiment can provide a projector that projects bright, high-quality images without color unevenness while being compact.

[0123] The technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, while the first embodiment describes a case where the light guide element 50 is composed of a hollow reflector, the entire light guide element 50 may be composed of a solid reflector made of a transparent material such as optical glass, and a reflective film made of a dielectric multilayer film or the like may be provided on the outer surface to act as a reflective surface. Also, while the second embodiment describes a case where the light guide element 51, the third embodiment describes a light guide element 52, and the fourth embodiment describes a case where the light guide elements 51, 52, and 53 are composed of solid reflectors, the light guide elements 51, 52, and 53 may be composed of hollow reflectors made by combining transparent plate-shaped members.

[0124] Furthermore, the specific details regarding the shape, number, arrangement, materials, etc., of each component of the image forming module and projector are not limited to the above embodiment and can be modified as appropriate.

[0125] A summary of this disclosure is provided below.

[0126] (Note 1) A first light source that emits first light in the first wavelength band, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light guide element that guides the first light emitted from the first light source and the second light emitted from the second light source internally, and emits the first light and the second light from a single emission end, The system includes an optical modulation device that modulates the light emitted from the light guide element according to image information, The aforementioned light guide element is A leading light section includes a first incident end into which the first light emitted from the first light source is incident, and which guides the first light to the exit end, It includes a second incident end into which the second light emitted from the second light source is incident, and a first sub-light guide that causes the second light to merge with the main light section, An image forming module characterized by the following features.

[0127] In this image forming module configuration, a single optical component can be used to construct the light guide element that guides the first and second light incident from the first and second light sources and emits it from the exit end toward the optical modulator. As a result, since there is only one light guide element and a combining prism is not required to combine the light from each light guide element, the image forming module can be made smaller compared to conventional configurations that use multiple light guide elements.

[0128] (Note 2) The system further comprises a third light source that emits third light in a third wavelength band different from the first and second wavelength bands, The light guide element further includes a third incident end into which the third light emitted from the third light source is incident, and a second sub-light guide section that merges the third light with the main light section. The image forming module described in Appendix 1, characterized by the features described herein.

[0129] With this configuration, a single optical element can guide three colored lights emitted from three light sources into the optical modulation device. Therefore, this configuration allows for a smaller device compared to the conventional three-plate system.

[0130] (Note 3) The first light source, the second light source, and the third light source emit the first light, the second light, and the third light in time sequence. The image forming module described in Appendix 2, characterized by the features described herein.

[0131] With this configuration, the first, second, and third beams of light can be emitted sequentially from the light guide element's emission end as illumination light and incident on the light modulator. Therefore, a three-color image can be generated using a single light modulator.

[0132] (Note 4) The aforementioned first light is green light, The aforementioned second light is red light, The third light is blue light. The image forming module described in Appendix 3, characterized by the features described herein.

[0133] This configuration provides an image forming module that generates green, red, and blue image light to form a full-color image.

[0134] (Note 5) The light guide element further comprises a polarization conversion member that converts the polarization directions of the first and second light emitted from the emission end of the light guide element to a predetermined polarization direction. An image forming module as described in any one of the appendices 1 to 4, characterized by the features described herein.

[0135] With this configuration, by including a polarization conversion member, the first and second light emitted from the exit end of the light guide element can be aligned to a predetermined polarization direction. Therefore, the first and second light can be efficiently incident on the optical modulation device. Thus, the light emitted from the first and second light sources can be efficiently used to generate image light, improving the light utilization efficiency of the image forming module.

[0136] (Note 6) The light guide element is composed of a hollow optical member. An image forming module as described in any one of the appendices 1 to 5, characterized by the above.

[0137] With this configuration, a light guide element can be easily constructed by combining plate-shaped members.

[0138] (Note 7) The aforementioned light guide element is Multiple prism components, The set includes a plurality of optical films arranged on the bonding surface of the plurality of prism members, The plurality of prism members and the plurality of optical films form a first light guide path that guides the first light toward the exit end and a second light guide path that guides the second light toward the exit end within the leading light portion. An image forming module as described in any one of the appendices 1 to 5, characterized by the above.

[0139] With this configuration, the first and second beams of light can be guided through the first and second beam guides to the inside of the main beam section, and the first and second beams of light can be emitted from the emission end.

[0140] (Note 8) The plurality of optical films include a selective transmission film provided at the junction surface between the prism member constituting the main light portion and the prism member constituting the first sub-light guide portion, which selectively transmits the second light. The transmittance of the selective transparent film to the second light varies depending on the angle of incidence of the second light to the selective transparent film. The image forming module described in Appendix 7, characterized by the features described herein.

[0141] In this configuration, the selective transparent film functions as a transparent film for the second light incident from the first secondary light guide and as a reflective film for the first light guiding the main light source. Furthermore, the selective transparent film can suppress leakage of the first light guiding the main light source to the first secondary light guide. Therefore, the first light can be efficiently extracted from the exit end.

[0142] (Note 9) A portion of the plurality of optical films constitutes a first reflective film in the second light guide path that reflects the component of the second light incident from the first sub-light guide to the main light source that is directed toward the first incident end. The image forming module according to Appendix 7 or Appendix 8, characterized by the features described herein.

[0143] With this configuration, the second light beam directed toward the first incident end is reflected by the first reflective film, allowing the second light beam to be efficiently extracted from the exit end.

[0144] (Note 10) Other portions of the plurality of optical films further constitute a second reflective film in the second light guide path that reflects the component of the second light incident from the first sub-light guide to the main light source that directly incident on the exit end. The image forming module described in Appendix 9, characterized by the features described herein.

[0145] This configuration prevents the first light from being emitted outward from the emission end without being reflected even once inside the main light source, and allows the in-plane illuminance of the first light emitted from the emission end to be made uniform by reflecting the first light multiple times inside the main light source.

[0146] (Note 11) The first optical axis of the leading light section and the second optical axis of the first auxiliary light guide section are orthogonal to each other. A portion of the plurality of optical films constitutes a third reflective film that reflects the second light in a direction perpendicular to the first and second optical axes within the second optical path, such that the difference between the in-plane illuminance of the first light guiding through the first optical path and the in-plane illuminance of the second light guiding through the second optical path is reduced. An image forming module as described in any one of the appendices 7 to 10, characterized by the features described herein.

[0147] This configuration allows for the emission of first and second light sources from the emission end, where the difference in uniformity of in-plane illuminance is small. Therefore, this image forming module can generate higher quality image light with reduced color unevenness.

[0148] (Note 12) An image forming module described in any one of the appendices 1 to 11, The system includes a projection optical system that projects light emitted from the image forming module, A projector characterized by the following features.

[0149] This projector configuration, by incorporating a small image forming module, allows for a compact projector that projects bright images. [Explanation of Symbols]

[0150] 1,1A…Image forming module, 5…Projection optical system, 11…Light source, 11…Green light source (first light source), 12…Red light source (second light source), 13…Blue light source (third light source), 17…Polarization conversion member, 20…Optical modulation device, 50,51,52,53…Light guide element, 100…Projector, 150,250,260,350…Lead light section, 150a,250a,260a…First incident end, 150b,250b,260b,350b…Exit end, 150C…First optical axis, 151,251,261,351…First secondary light guide section, 151a,251a…Second Incident end, 151C...Second optical axis, 152, 252, 262, 352...Second sub-light guide section, 152a, 252a...Third incident end, 153, 253...First selective transmission film (selective transmission film), 200, 210, 230...Prism member, 201, 202, 203...Optical film, 255, 265...First incident side reflective film (first reflective film), 267...First exit side reflective film (second reflective film), 361...First upper and lower reflective films (third reflective film), LG...Green light (first light), LR...Red light (second light), LB...Blue light (third light), LT1...First light guide path, LT2...Second light guide path.

Claims

1. A first light source that emits first light in the first wavelength band, A second light source that emits second light in a second wavelength band different from the first wavelength band, A light guide element that guides the first light emitted from the first light source and the second light emitted from the second light source internally, and emits the first light and the second light from a single emission end, The system includes an optical modulation device that modulates the light emitted from the light guide element according to image information, The aforementioned light guide element is A leading light section includes a first incident end into which the first light emitted from the first light source is incident, and which guides the first light to the exit end, It includes a second incident end into which the second light emitted from the second light source is incident, and a first sub-light guide section that causes the second light to merge with the main light section, An image forming module characterized by the following features.

2. The system further comprises a third light source that emits a third light in a third wavelength band different from the first and second wavelength bands, The light guide element further includes a third incident end into which the third light emitted from the third light source is incident, and a second sub-light guide section that merges the third light with the main light section. The image forming module according to feature 1.

3. The first light source, the second light source, and the third light source emit the first light, the second light, and the third light in time sequence. The image forming module according to feature 2.

4. The first light is green light, The aforementioned second light is red light, The third light mentioned above is blue light. The image forming module according to feature 3.

5. The system further comprises a polarization conversion member that converts the polarization directions of the first and second light emitted from the emission end of the light guide element to a predetermined polarization direction. The image forming module according to feature 1.

6. The light guide element is composed of a hollow optical member. The image forming module according to feature 1.

7. The aforementioned light guide element is Multiple prism components, The set includes a plurality of optical films arranged on the bonding surface of the plurality of prism members, The plurality of prism members and the plurality of optical films form a first light guide path that guides the first light toward the exit end and a second light guide path that guides the second light toward the exit end within the leading light portion. The image forming module according to feature 1.

8. The plurality of optical films include a selective transmission film provided at the junction surface between the prism member constituting the main light portion and the prism member constituting the first sub-light guide portion, which selectively transmits the second light. The transmittance of the selectively permeable film to the second light varies depending on the angle of incidence of the second light to the selectively permeable film. The image forming module according to feature 7.

9. A portion of the plurality of optical films constitutes a first reflective film in the second light guide path that reflects the component of the second light incident from the first sub-light guide to the main light source that is directed toward the first incident end. The image forming module according to feature 7.

10. Other portions of the plurality of optical films further constitute a second reflective film in the second light guide path that reflects the component of the second light incident from the first sub-light guide to the main light source that directly incident on the exit end. The image forming module according to feature 9.

11. The first optical axis of the leading light section and the second optical axis of the first auxiliary light guide section are orthogonal to each other. A portion of the plurality of optical films constitutes a third reflective film that reflects the second light in a direction perpendicular to the first and second optical axes within the second optical path, such that the difference between the in-plane illuminance of the first light guiding through the first optical path and the in-plane illuminance of the second light guiding through the second optical path is reduced. The image forming module according to feature 7.

12. An image forming module according to any one of claims 1 to 11, The system includes a projection optical system that projects light emitted from the image forming module, A projector characterized by the following features.

Images