TW201531755A - Display module and light guide device - Google Patents

Abstract

A display module is provided. A light source is configured to provide an illumination beam. A light guide plate has a first surface, a second surface opposite to the first surface, and an incident surface connecting the first surface and the second surface. The illumination beam enters the light guide plate through the incident surface. A reflective element is connected to the light guide plate and has a plurality of first reflective surfaces inclined with respect to the second surface. A reflective display unit is capable of modulating a polarization state of the illumination beam to form a modulated beam. The second surface is disposed between the reflective display unit and the first surface. The first surface is disposed between the second surface and a reflective polarizer, and the reflective polarizer filters the modulated beam into an image beam.

Description

Display module and light guiding device

The invention relates to a display module and a light guiding device.

In the field of display of display devices, various types of spatial light modulators are used to convert an illumination beam into an image beam, such as a transmissive liquid crystal display (LCD) panel, liquid crystal overlay. A liquid-crystal-on-silicon (LCOS) panel or a digital micro-mirror device (DMD). The light efficiency of the transmissive LCD panel is lower than that of the LCOS panel, and the cost of the DMD is greater than the cost of the LCOS panel.

Generally, in a projector using an LCOS panel, an s-polarized beam is reflected to an LCOS panel by a polarizing beam splitter (PBS). Next, the LCOS panel modulates the s-polarized beam into a polarized beam of other polarization states and reflects the polarized beam to the PBS. The PBS filters the polarized beam into an image beam, which is then transmitted to an image-forming lens. Finally, the imaging lens projects the image beam onto the screen to form an image on the screen or to create a virtual image in the air or on any other virtual image plane.

In a projector using an LCOS panel, the splitting plane of the PBS is continuous, and It is inclined by about 45 degrees with respect to the LCOS panel, so that the PBS takes up a large space between the LCOS panel and the imaging lens. Therefore, the distance between the imaging lens and the LCOS panel is so long that the projector is thick and cumbersome.

The present invention provides a display module having a small thickness, high contrast, and high light efficiency.

The present invention provides a light guiding device that can efficiently guide a light beam and has high light efficiency.

An embodiment of the invention provides a display module including at least one light source, a light guide plate, a reflective element, a reflective display unit, and a reflective polarizer. The at least one light source is configured to provide at least one illumination beam. The light guide plate has a first surface, a second surface opposite to the first surface, and at least one incident surface connecting the first surface and the second surface. The illumination beam enters the light guide plate through the incident surface. The reflective element is coupled to the light guide plate and is configured to change a direction of propagation of at least a portion of the illumination beam. The reflective element has a plurality of first reflective surfaces that are inclined relative to the second surface. The reflective display unit is capable of modulating a polarization state of the illumination beam to form a modulated beam. The second surface is disposed between the reflective display unit and the first surface. The first surface is disposed between the second surface and the reflective polarizer. The reflective polarizer filters the modulated beam into an image beam.

An embodiment of the invention provides a light guiding device comprising a light guide plate and a reflective element. The light guide plate has a first surface, a second surface relative to the first surface, and a connection At least one incident surface of the first surface and the second surface. At least one light beam enters the light guide plate through the at least one incident surface. The reflective element is coupled to the light guide plate and is configured to change a direction of propagation of at least a portion of the illumination beam. The reflective element has a plurality of first reflective surfaces that are inclined relative to the second surface.

In view of the above, in a display module according to an embodiment of the present invention, a light guide plate, a reflective element, and a reflective polarizer are used to guide an illumination beam to a reflective display unit. Because the light guide plate has a small thickness, the display module has a small thickness and volume. Further, in the light guiding device according to the embodiment of the present invention, since the reflecting member is used to change the propagation direction of the light beam, the light guiding means can effectively guide the light beam.

The above described features and advantages of the invention will be apparent from the following description.

100, 100a, 100b, 100f‧‧‧ display modules

110‧‧‧Light source

112‧‧‧Lighting elements

114‧‧‧ polarizer

120, 120a, 120b, 120c, 120d, 120e, 120f‧‧‧ light guide plate

122, 122d, 122e‧‧‧ first surface

124‧‧‧ second surface

126, 126a‧‧‧ incident surface

128‧‧‧ third surface

130, 130a, 130b, 130c, 130f‧‧‧ reflective elements

131‧‧‧First reflective surface

131f‧‧‧second reflective surface

132‧‧‧First slope

134, 134f‧‧‧ connecting parts

134c‧‧‧Second inclined part

136, 136c‧‧‧ top connection section

138c‧‧‧ bottom connection section

140‧‧‧Reflective display unit

150‧‧‧Reflective polarizer

160‧‧‧ reflector

170‧‧‧ imaging lens

180‧‧‧Optical coupling optics

190‧‧‧focus lens

200, 200c, 200d, 200e‧‧‧ light guides

1202, 1202f‧‧‧ first sub-light guide

1202c, 1204c‧‧‧ sub-light guide

1204, 1204f‧‧‧Second sub-light guide

I‧‧·Image beam

M‧‧‧ modulated beam

P‧‧‧Lighting beam

P', P1‧‧ ‧ pitch

T‧‧‧ thickness

U‧‧‧Unpolarized beam

W, W'‧‧‧Width

1 is a schematic cross-sectional view of a display module in accordance with an embodiment of the present invention.

2 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention.

3 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention.

4 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention.

Figure 5 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention.

Figure 6 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention.

Figure 7 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention.

1 is a schematic cross-sectional view of a display module in accordance with an embodiment of the present invention. Referring to FIG. 1, the display module 100 in this embodiment includes at least one light source 110 (one light source 110 is exemplarily shown in FIG. 1), a light guide plate 120, a reflective element 130, a reflective display unit 140, and a reflective polarizer. 150. The light source 110 is used to provide an illumination beam P, ie, a beam of light. In this embodiment, light source 110 includes at least one light emitting element 112 (one light emitting element is exemplarily shown in FIG. 1) and polarizer 114. The illuminating element 112 is configured to emit an unpolarized beam U. The polarizer 114 is disposed on the path of the unpolarized beam U and is used to filter the unpolarized beam U into a polarized beam, wherein the illumination beam P is a polarized beam. In detail, the polarizer 114 is a reflective polarizer that allows a portion of the unpolarized light beam U having the first polarization direction to pass therethrough, and reflects another portion of the unpolarized light beam U having the second polarization direction back to the light emitting element 112. . The polarizer 114 can be a dual brightness enhancement film (DBEF) or any other reflective polarizer. However, in other embodiments, polarizer 114 can be an absorbing polarizer that allows portions of the unpolarized beam U having a first polarization direction to pass through and absorb portions of the non-polarized beam U that have a second polarization direction. In this embodiment, the first polarization direction is perpendicular to the second polarization direction. In other embodiments, light source 110 may not include polarizer 114, and light source 110 provides an unpolarized beam; that is, illumination beam P may be an unpolarized beam. However, in other embodiments, light source 110 can be a polarized light source, such as a laser light source, and illumination beam P is a polarized beam, and source 110 does not include polarizer 114.

In this embodiment, the light emitting element 112 is a light-emitting diode (LED), for example, a white light LED. The white LED may have a blue LED chip to emit blue light and an encapsulant that encapsulates the blue LED. When the blue light excites the phosphor in the package, the phosphor converts the blue light into yellow light. The unconverted blue light and yellow light are mixed to form white light, that is, the unpolarized light beam U. However, in other embodiments, light source 110 can include a plurality of light emitting elements that emit light of a plurality of colors (eg, primary colors). For example, light source 110 can include red, green, and blue LEDs to emit red, green, and blue light, respectively. A portion of the unpolarized beam having a second polarization direction and reflected by the polarizer 114 (eg, a blue portion) can excite a phosphor (eg, a yellow phosphor) in the package of the LED to achieve light recovery and increase the source 110 light efficiency. In other embodiments, light source 110 can include a laser emitter (eg, a laser diode) that emits a laser having multiple colors to form an illumination beam P, respectively.

The light guide plate 120 has a first surface 122, a second surface 124 relative to the first surface 122, and at least one incident surface 126 connecting the first surface 122 and the second surface 124 (one incident surface is exemplarily shown in FIG. 1) . The illumination beam P enters the light guide plate 120 through the incident surface 126.

In this embodiment, the first surface 122 is an interface between the first medium (ie, the material of the light guide plate 120) in the light guide plate 120 and the second medium (for example, air) outside the light guide plate 120, and the first medium The refractive index is greater than the refractive index of the second medium. Further, in this embodiment, the second The surface 124 is an interface between the first medium (ie, the material of the light guide plate 120) in the light guide plate 120 and the third medium (for example, air) outside the light guide plate 120, and the refractive index of the first medium is greater than the refraction of the third medium. rate. Accordingly, the illumination beam P from the incident surface 126 can be repeatedly totally internally reflected by the first surface 122 and the second surface 124 such that the illumination beam P can be transmitted opposite the incident surface 126 and connect the first surface 122 and the second surface 124 The third surface 128.

The reflective element 130 is coupled to the light guide plate 120 and is used to change the direction of propagation of the illumination beam P. The reflective element 130 has a plurality of reflective surfaces 131 that are inclined relative to the second surface 124. In this embodiment, the reflective element 130 includes a plurality of first inclined portions 132, a plurality of connecting portions 134, and a plurality of top connecting portions 136. The first inclined portions 132 have first reflective surfaces 131, respectively. The connecting portions 134 are respectively connected to the first inclined portions 132, wherein each of the connecting portions 134 and the corresponding one of the first inclined portions 132 form a V shape. Each of the top connection portions 136 connects the top end of one of the connection portions 134 with the top end of one of the first inclined portions 132 and is between two adjacent V-shapes.

In this embodiment, the reflective element 130 is a polarizing beam splitter (PBS film), and the first inclined portion 132 reflects at least a portion of the illumination beam P from the incident surface 126 having a first polarization direction. Further, in this embodiment, the first inclined portion 132 and the connecting portions (each of which includes the connecting portion 134 and the top connecting portion 136) are alternately connected. The polarizing beam splitting film allows light having a first polarization direction and incident perpendicularly to the polarizing beam splitting film to pass therethrough, and allows light having a second polarization direction and incident substantially perpendicularly (for example, an incident angle of less than 40 degrees) to the polarizing beam splitting film . In this embodiment, the first polarization direction is substantially parallel to the second surface 124 and the first reflective surface 131, and the second polarization direction is substantially perpendicular to the first polarization direction. That is, the first polarization direction is s-polarization and the second polarization direction is p-polarization.

In this embodiment, when the s-polarized light is obliquely incident on the polarizing beam splitting film at a large incident angle (for example, greater than 40 degrees), the polarizing beam splitting film reflects s-polarized light. When the p-polarized light is obliquely incident on the polarizing beam splitting film at a large incident angle (for example, greater than 40 degrees), the polarizing beam splitting film reflects p-polarized light. However, when the incident angle is small (for example, less than 40 degrees), both the p-polarized light and the s-polarized light pass through the polarizing beam splitting film.

The second surface 124 is disposed between the reflective display unit 140 and the first surface 122. When the illumination beam P from the incident surface 126 is obliquely incident on the first inclined portion 132, since the illumination beam P is an s-polarized beam, the first inclined portion 132 changes the direction of propagation of the illumination beam P, for example, at least a portion of the illumination beam P is reflected It is passed through the second surface 124 and passed to the reflective display unit 140. Since the direction of propagation of the illumination beam P changes, a portion of the illumination beam P can be incident on the second surface 124 at an angle less than the critical angle. Therefore, the illumination light beam P reflected by the first inclined portion 132 can pass through the second surface 124.

The first surface 122 is disposed between the second surface 124 and the reflective polarizer 150. In this embodiment, reflective polarizer 150 reflects light having a first polarization direction (eg, s-polarized light) and allows light having a second polarization direction (eg, p-polarized light) to pass through. Because the illumination beam P from the incident surface 126 has a first polarization direction, the illumination beam that is not reflected by the first sloped portion 132 and passes through the connection portion (which may include the connection portion 134 and the top connection portion 136) and the first surface 122 P is reflected back to the first surface 122 by the reflective polarizer 150 and then transmitted in the light guide plate 120.

The illumination beam P reflected by the reflective polarizer 150 can pass through the first surface 122 and the second surface 124 in sequence to the reflective display unit 140.

In this embodiment, although the reflective polarizer 150 is disposed on the first surface 122, However, there may be an air gap between the reflective polarizer 150 and the first surface 122. Therefore, the first surface 122 may be an interface between the air and the material of the light guide plate 120.

In this embodiment, the display module 100 further includes a reflector 160 disposed on the third surface 128. The reflector 160 reflects a portion of the illumination beam P that does not pass through the second surface 124 such that this portion of the illumination beam P can still be transmitted in the light guide plate 120. Therefore, the probability that the illumination beam P is reflected by the first inclined portion 132, passes through the second surface 124, and reaches the reflective display unit 140 is increased. Therefore, the light efficiency and uniformity of the display module 100 are improved.

The reflective display unit 140 is capable of modulating the polarization state of the illumination beam P to form a modulated beam M. The reflective display unit 140 can be a microdisplay. In this embodiment, the reflective display unit 140 is a liquid crystal on silicon (LCOS) panel for modulating and reflecting the illumination beam P. For example, at least a portion of the illumination beam P can be modulated from an s-polarized beam to a p-polarized beam, a beam having a circularly polarized state or an elliptical polarization state, or the illumination beam P is unmodulated and remains as an s-polarized beam. In other words, the modulated beam M can comprise an s-polarized beam, a p-polarized beam, a circularly polarized beam, an elliptically polarized beam, or any combination thereof. In other embodiments, the reflective display unit 140 can be a micro-electromechanical system (MEMS) display, such as a digital micro-mirror device (DMD).

Reflective polarizer 150 filters modulated beam M into image beam I. In this embodiment, the reflective polarizer 150 allows a portion of the modulated beam M having a second polarization direction (eg, p-polarization) to pass through, and the reflected modulated beam M has a first polarization direction (eg, The part of s-polarization). Therefore, the portion of the modulated light beam M that passes through the reflective polarizer 150 having the second polarization direction forms the image beam I. Because of the incidence of the incident top connecting portion 136 The incident angle of the modulated beam M is small (e.g., less than 40 degrees), so both the s-polarized portion and the p-polarized portion of the modulated beam M pass through the top connecting portion 136. Further, the p-polarized portion of the modulated light beam M passes through the first inclined portion 132. Because image beam I is p-polarized and because p-polarized light can pass through reflective element 130, reflective element 130 does not negatively affect imaging of display module 100. Therefore, the contrast and light efficiency of the display module 100 are improved, and the ghosting problem of the image is solved.

In this embodiment, the display module 100 further includes an image-forming lens 170 disposed on the path of the image beam I from the reflective polarizer 150 to form a real image on the screen or in the air or any A virtual image is formed on other virtual image planes. If the imaging lens 170 forms a real image on the screen, the display module 100 is a real image projector. If the imaging lens forms a virtual image in the air or any other virtual image plane, the display module 100 is a virtual image display, such as a head-mounted display (HMD) or a head-up display (HUD). When all portions of the modulated beam M have a second polarization direction, then the real or virtual image forms a white frame. When all portions of the modulated light beam M have a first polarization direction, then the real or virtual image forms a black frame. If portions of the modulated beam have various polarization states, such as a circular polarization state, an elliptical polarization state, a p-polarization state, and an s-polarization state, portions of the modulated beam are worn at different locations of the reflective polarizer 150. The reflective polarizer 150 is passed over so that image frames are formed.

In the display module 100 according to this embodiment, the light guide plate 120, the reflective element 130, and the reflective polarizer 150 are used to guide the illumination light beam P to the reflective display unit 140. The light guide plate has a smaller thickness than the polarizing beam splitter (PBS) to make the display module have a smaller thickness and volume. That is, the display module 100 can have an ultra-thin profile. Therefore, it can be effective Reduce the size of the HMD, HUD or projector. In an embodiment, the thickness T of the light guide plate 120 may be less than 10 mm.

In this embodiment, the display module 100 further includes a light coupling optic 180 disposed on the incident surface 126 and configured to collect the illumination beam P from the light source 110. Light coupling optical element 180 can be a lens (eg, a convex lens) or a curved surface (eg, a convex surface). In this embodiment, the light guide plate 120, the reflective element 130, the reflector 160, the optical coupling optical element 180, and the reflective polarizer 150 can form a light guiding device.

In this embodiment, the display module 100 further includes a focusing lens 190 disposed on the path of the image beam I between the reflective display unit 140 and the second surface 124. In another embodiment, the focusing lens 190 may not be employed to further reduce the thickness of the display module 100.

In this embodiment, the reflective element 130 is a multilayer film, and the material of the reflective element 130 comprises titanium oxide (eg, TiO ₂ or Ti ₃ O ₅ ), tantalum oxide (eg, Ta ₂ O ₅ ), tantalum oxide (eg, SiO ₂ ), aluminum oxide (for example, Al ₂ O ₃ ), magnesium oxide (MgO), or a combination thereof. In this embodiment, the multilayer film has from 2 to 100 layers, and each of the layers has a thickness ranging from 10 nanometers to 1 micrometer. However, in other embodiments, reflective element 130 can be a metal layer, such as an aluminum (Al) or silver (Ag) layer. Further, in this embodiment, the reflective element satisfies 0.5 μm ≦W<P1 ≦ 100 μm, where W is the width of each of the first reflective surfaces 131, and P1 is each of the first reflective surfaces 131 The pitch. Further, in this embodiment, the first reflective surface 131 is inclined by 25 to 60 degrees with respect to the second surface 124.

In this embodiment, the light guide plate 120 includes a first sub-light guide plate 1202 having a first surface 122 and a second sub-light guide plate 1204 having a second surface 124, and the reflective element 130 is sandwiched between the first sub-light guide plate 1202 and the first Between the two sub-light guide plates 1204, and located at the first surface 122 and the second Between the surfaces 124. In this embodiment, the material of the light guide plate 120 is a transparent material such as plastic or glass.

Further, the light guide plate 120, the reflective polarizer 150, the reflective element 130, and the reflector 160 form the light guiding device 200.

2 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention. Referring to FIG. 2, the display module 100a in this embodiment is similar to the display module 100 in FIG. 1, and the main differences between the two are as follows. In this embodiment, the pitch P' of the first reflective surface 131 of the reflective element 130a gradually decreases in a direction away from the incident surface 126a (i.e., a leftward direction in FIG. 2). Since the light energy density of the illumination beam P decreases in the direction, the light energy density is small at the end of the light guide plate 120a away from the incident surface 126a. Therefore, the denser first reflective surface 131 can reflect more of the illumination beam P such that the illumination beam P incident on the reflective display unit 140 is uniform. Further, in this embodiment, the incident surface 126a is a flat surface.

3 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention. Referring to FIG. 3, the display module 100b in this embodiment is similar to the display module 100 in FIG. 1, and the main differences between the two are as follows. In this embodiment, the width W' of the first reflective surface 131 of the reflective element 130b gradually increases in a direction away from the incident surface 126a (i.e., a leftward direction in FIG. 3). Since the light energy density of the illumination beam P decreases in the direction, the light energy density is small at the end of the light guide plate 120b away from the incident surface 126a. Therefore, the larger first reflective surface 131 can reflect more of the illumination beam P such that the illumination beam P incident on the reflective display unit 140 is uniform.

4 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention. Referring to FIG. 4, the light guiding device 200c in this embodiment is similar to the light guiding device 200 in FIG. The main differences between the two are as follows. In the light guiding device 200c, the reflective member 130c further includes a plurality of second inclined portions 134c and a plurality of bottom connecting portions 138c. The second inclined portion 134c is inclined with respect to the second surface 124, wherein the first inclined portion 132 and the second inclined portion 134c are alternately arranged. In this embodiment, the first inclined portion 132 and the second inclined portion 134c may be substantially parallel to each other.

Each of the top connecting portions 136c connects the top end of one of the first inclined portions 132 adjacent to each other and the top end of one of the second inclined portions 134c. Each of the bottom connecting portions 138c connects the bottom end of one of the first inclined portions 132 adjacent to each other and the bottom end of one of the second inclined portions 134c. Further, the top connecting portion 136c and the bottom connecting portion 138c are alternately connected.

Further, the reflective member 130c is sandwiched between the sub-light guide plate 1204c of the light guide plate 120c and the sub-light guide plate 1202c.

Figure 5 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention. Referring to Fig. 5, the light guiding device 200d in this embodiment is similar to the light guiding device 200 in Fig. 1, and the main difference between the two is as follows. In the light guiding device 200d, the reflective member 130 is disposed on the first surface 122d of the light guide plate 120d, wherein the light guide plate 120d is a single plate, and the reflective polarizer 150 is disposed on the reflective member 130.

Figure 6 is a schematic cross-sectional view of a light guiding device in accordance with another embodiment of the present invention. Referring to Fig. 6, the light guiding device 200e in this embodiment is similar to the light guiding device 200c in Fig. 4, and the main difference between the two is as follows. In the light guiding device 200e, the reflective member 130c is disposed on the first surface 122e of the light guide plate 120e, wherein the light guide plate 120e is a single plate, and the reflective polarizer 150 is disposed on the reflective member 130c.

Figure 7 is a schematic cross-sectional view of a display module in accordance with another embodiment of the present invention. Referring to FIG. 7, the display module 100f in this embodiment is similar to the display module 100 in FIG. 1, and the main differences between the two are as follows. In display module 100f, there are two opposing incident surfaces 126a and two light sources 110 disposed adjacent to two opposing incident surfaces 126a, respectively. Each of the connecting portions 134f of the reflective member 130f has a second reflective surface 131f that is inclined with respect to the second surface 124. In FIG. 7, the second reflective surface 131f can reflect the illumination beam P from the left incident surface 126a. In addition, in the embodiment, the reflective element 130f is sandwiched between the first sub-light guide plate 1202f and the second sub-light guide plate 1204f of the light guide plate 120f.

In summary, in the display module according to the embodiment of the invention, the light guide plate, the reflective element and the reflective polarizer are used to guide the illumination beam to the reflective display unit. Because the light guide plate has a small thickness, the display module has a small thickness and volume. Further, in the light guiding device according to the embodiment of the present invention, since the reflecting member is used to change the propagation direction of the light beam, the light guiding means can effectively guide the light beam. In addition, since the reflective element does not negatively affect the imaging of the display module, the contrast and light efficiency of the display module 100 is improved, and the image ghosting problem is solved.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧ display module

110‧‧‧Light source

112‧‧‧Lighting elements

114‧‧‧ polarizer

120‧‧‧Light guide

122‧‧‧ first surface

124‧‧‧ second surface

126‧‧‧ incident surface

128‧‧‧ third surface

130‧‧‧reflecting elements

131‧‧‧First reflective surface

132‧‧‧First slope

134‧‧‧Connected section

136‧‧‧Top connection section

140‧‧‧Reflective display unit

150‧‧‧Reflective polarizer

160‧‧‧ reflector

170‧‧‧ imaging lens

180‧‧‧Optical coupling optics

190‧‧‧focus lens

200‧‧‧Light guide

1202‧‧‧First sub-light guide

1204‧‧‧Second sub-light guide

I‧‧·Image beam

M‧‧‧ modulated beam

P‧‧‧Lighting beam

P1‧‧‧ pitch

T‧‧‧ thickness

U‧‧‧Unpolarized beam

W‧‧‧Width

Claims (34)

A display module comprising: at least one light source for providing at least one illumination beam; a light guide plate having a first surface, a second surface opposite to the first surface, and a connection between the first surface and the second At least one incident surface of the surface, the illumination beam entering the light guide plate through the incident surface; a reflective element coupled to the light guide plate and configured to change a direction of propagation of at least a portion of the illumination beam, The reflective element has a plurality of first reflective surfaces that are inclined relative to the second surface; a reflective display unit capable of modulating a polarization state of the illumination beam to form a modulated beam, the second surface being disposed at the reflection Between the display unit and the first surface; and a reflective polarizer, the first surface is disposed between the second surface and the reflective polarizer, the reflective polarizer will The modulated beam is filtered into an image beam. The display module of claim 1, wherein the reflective element is a polarizing beam splitting film, and includes a plurality of inclined portions for respectively forming the plurality of first reflecting surfaces, and the inclined portion reflects The illumination beam from the incident surface has at least a portion of a first polarization direction. The display module of claim 2, wherein the reflective element further comprises a plurality of connecting portions, the inclined portion and the connecting portion are alternately connected, and the polarization splitting film allows the first polarization Light passing through the polarizing beam splitting film in a direction and approximately perpendicularly passes through, and allows light having a second polarization direction and incident on the polarizing beam splitting film approximately perpendicularly The first polarization direction is substantially parallel to the second surface and the first reflective surface, and the second polarization direction is substantially perpendicular to the first polarization direction. The display module of claim 2, wherein the reflective element is a multilayer film. The display module of claim 4, wherein the material of the reflective element comprises titanium oxide, cerium oxide, cerium oxide, aluminum oxide, magnesium oxide or a combination thereof. The display module of claim 4, wherein the multilayer film has 2 to 100 layers. The display module of claim 6, wherein each of the layers has a thickness ranging from 10 nm to 1 μm. The display module of claim 1, wherein the reflective element satisfies 0.5 micrometers <W<P≦100 micrometers, where W is the width W of each of the first reflective surfaces, and P Is the pitch of each of the first reflective surfaces. The display module of claim 1, wherein the reflective element is disposed on the first surface of the light guide plate. The display module of claim 1, wherein the light guide plate comprises a first sub-light guide plate having the first surface and a second sub-light guide plate having the second surface, and the reflection The component is sandwiched between the first sub-light guide plate and the second sub-light guide plate and located between the first surface and the second surface. The display module of claim 1, wherein the reflective element comprises: a plurality of first inclined portions each having the plurality of first reflective surfaces; and a plurality of second inclined portions relative to the The second surface is inclined, wherein the first inclined portion And the second inclined portions are alternately arranged; a plurality of top connecting portions, each of the top connecting portions connecting a top end of the one of the first inclined portions adjacent to each other and the second inclined portion a top end of one of the bottom portions; and a plurality of bottom connecting portions, each of the bottom connecting portions connecting a bottom end of one of the first inclined portions adjacent to each other and the second inclined portion A bottom end of one of the top connection portions and the bottom connection portion are alternately connected. The display module of claim 1, wherein the reflective element comprises: a plurality of first inclined portions each having the plurality of first reflective surfaces; and a plurality of connecting portions respectively connected to the plurality of a first inclined portion, wherein each of the connecting portions forms a V shape with a corresponding one of the inclined portions; and a plurality of top connecting portions, each of the top connecting portions connecting the connection The tip of one of the portions is at the top end of one of the first inclined portions and is between two adjacent V-shapes. The display module of claim 12, wherein the at least one incident surface comprises two opposite incident surfaces, and the at least one light source comprises two respectively disposed beside the two opposite incident surfaces And a light source, and each of the connecting portions has a second reflective surface that is inclined relative to the second surface. The display module of claim 1, wherein the first reflective surface is inclined by 25 to 60 degrees with respect to the second surface. The display module of claim 1, further comprising an imaging lens disposed on a path of the image beam from the reflective polarizer to form a real image or a virtual image. The display module of claim 1, wherein the reflective display unit is a microdisplay. The display module of claim 1, wherein the light guide plate further has a third surface opposite to the incident surface, the third surface connecting the first surface and the second surface, And the display module further includes a reflector disposed on the third surface. The display module of claim 1, further comprising a light coupling optical element disposed on the incident surface. The display module of claim 1, wherein the light source comprises: at least one light emitting element for emitting an unpolarized light beam; and a polarizer disposed on the path of the unpolarized light beam and used for The unpolarized beam is filtered into a polarized beam, wherein the illumination beam is the polarized beam. The display module of claim 1, wherein the light source is a polarized light source, and the illumination beam is a polarized light beam. A light guiding device comprising: a light guide plate having a first surface, a second surface opposite to the first surface, and at least one incident surface connecting the first surface and the second surface, at least one light beam passing through Introducing at least one incident surface into the light guide plate; and a reflective element coupled to the light guide plate and configured to change a direction of propagation of at least a portion of the illumination beam, the reflective element having a second surface relative to the second surface A plurality of first reflective surfaces that are inclined. The light guiding device of claim 21, further comprising a reflective polarizer disposed on the first surface. The light guiding device of claim 21, wherein the reflective element is a polarizing beam splitting film, and includes a plurality of inclined portions for respectively forming the plurality of first reflecting surfaces, and the inclined portion reflects The illumination beam from the incident surface has at least a portion of a first polarization direction. The light guiding device of claim 23, wherein the reflective member further comprises a plurality of connecting portions, the inclined portion and the connecting portion are alternately connected, and the polarizing beam splitting film is allowed to have the first polarizing Light incident on the polarization splitting film in a direction and approximately perpendicularly passes through and allows light having a second polarization direction and incident approximately perpendicularly on the polarization beam splitting film to pass through, the first polarization direction being substantially parallel The second surface and the first reflective surface, and the second polarization direction is substantially perpendicular to the first polarization direction. The light guiding device of claim 23, wherein the reflective element is a multilayer film. The light guiding device of claim 25, wherein the material of the reflective element comprises titanium oxide, cerium oxide, cerium oxide, aluminum oxide, magnesium oxide or a combination thereof. The light guiding device of claim 25, wherein the multilayer film has 2 to 100 layers. The light guiding device of claim 27, wherein each of the layers has a thickness ranging from 10 nm to 1 μm. The light guiding device of claim 21, wherein the reflective element satisfies 0.5 micrometers <W<P≦100 micrometers, where W is the width of each of the first reflective surfaces, and P is The pitch of each of the first reflective surfaces. The light guiding device of claim 21, wherein the reflective component is And disposed on the first surface of the light guide plate. The light guiding device of claim 21, wherein the light guide plate comprises a first sub-light guide plate having the first surface and a second sub-light guide plate having the second surface, and the reflection The component is sandwiched between the first sub-light guide plate and the second sub-light guide plate and located between the first surface and the second surface. The light guiding device of claim 21, wherein the reflecting element comprises: a plurality of first inclined portions each having the plurality of first reflecting surfaces; and a plurality of second inclined portions, relative to the The second surface is inclined, wherein the first inclined portion and the second inclined portion are alternately arranged; a plurality of top connecting portions, each of the top connecting portions being connected in the first inclined portion adjacent to each other a top end of one of the top and the second inclined portion; and a plurality of bottom connecting portions, each of the bottom connecting portions connecting one of the first inclined portions adjacent to each other a bottom end of one of the bottom end and the second inclined portion, wherein the top connecting portion and the bottom connecting portion are alternately connected. The light guiding device of claim 21, wherein the reflective element comprises: a plurality of first inclined portions each having the plurality of first reflective surfaces; and a plurality of connecting portions respectively connected to the plurality of a first inclined portion, wherein each of the connecting portions forms a V shape with a corresponding one of the inclined portions; and a plurality of top connecting portions, each of the top connecting portions connecting the corresponding V shape a top end of one of the connecting portions and a top end of one of the first inclined portions. The light guiding device of claim 33, wherein the at least one incident surface comprises two opposite incident surfaces, and each of the connecting portions has a tilt relative to the second surface Two reflective surfaces.