Polarization conversion element and light source module having same

Abstract

The present invention relates to: a polarization conversion element capable of converting the polarizations of all light incident on a liquid crystal panel, into linear polarization in a specific state, to minimize light absorption in a polarizing plate and increase light utilization efficiency; and a light source module comprising the polarization conversion element. The present invention may provide a light source module comprising a plurality of light-emitting elements for generating unpolarized light beams, a polarization conversion element for converting the unpolarized light beams into a polarized light beam having a first deflection direction, and a lens array for focusing the polarized light beam, wherein the polarization conversion element comprises a plurality of conversion units, each of the conversion units including a first plate inclined at 45 degrees from the optical axis and a second plate parallel to the first plate, and a first surface among both surfaces of the first plate, facing the lens array, is provided with a polarization separation layer, a second surface among both surfaces of the first plate, facing the light-emitting elements, is provided with a polarization conversion layer, and a third surface among both surfaces of the second plate, facing the lens array, is provided with an optical mirror layer.

Description

Polarization conversion element and light source module having the same

[0001] The present disclosure relates to a light source module for a display, such as a liquid crystal display (LCD). More specifically, the present disclosure relates to a polarization conversion element for increasing light efficiency and a light source module including the same.

[0002] A light source module can be used as a backlight unit for displays, such as liquid crystal displays (LCDs). The light beams projected onto the back of the LCD panel by the light source module refract in different patterns as they pass through each liquid crystal, forming individual pixels of different colors and brightnesses. These pixels, when combined, can form the entire screen.

[0003] However, in the case of liquid crystal displays (LCDs), only a portion of the total light emitted from the light source module is utilized as effective light. The primary cause of this reduced light utilization efficiency is light absorption in the LCD's polarizing plate.

[0004] The polarizing plate placed on one side of the liquid crystal panel basically absorbs 50% of the incident non-polarized beam, which reduces light utilization efficiency, and the light beam absorbed by the polarizing plate is converted into heat, which deteriorates display performance.

[0005] The present disclosure is proposed to solve the aforementioned problem, and aims to provide a polarization conversion element and a light source module including the same, which can increase light utilization efficiency by minimizing light absorption in a polarizing plate by converting the polarization of all light incident on a liquid crystal panel into linear polarization of a specific state.

[0006] In order to achieve the above object, according to one aspect of the present disclosure, a light source module including a plurality of light-emitting elements for generating an unpolarized light beam, a polarization conversion element for converting the unpolarized light beam into a polarized light beam in a first deflection direction, and a lens array for focusing the polarized light beam, wherein the polarization conversion element includes a plurality of conversion units, each conversion unit including a first plate inclined at 45 degrees from an optical axis and a second plate parallel to the first plate, a polarization separation layer is provided on a first surface of both sides of the first plate facing the lens array, a polarization conversion layer is provided on a second surface of both sides of the first plate facing the light-emitting elements, and a light mirror layer is provided on a third surface of both sides of the second plate facing the lens array.

[0007] The polarization separation layer can transmit a polarized light beam having a first deflection direction among the unpolarized light beams toward the lens array along the optical axis, and can reflect a polarized light beam having a second deflection direction among the unpolarized light beams toward the second plate along a direction orthogonal to the optical axis.

[0008] The above polarization conversion layer can convert the reflected polarized light beam in the second deflection direction into a polarized light beam in the first deflection direction.

[0009] The above optical mirror layer can reflect the polarized light beam of the converted first deflection direction toward the lens array along the optical axis.

[0010] The light source module may further include a collimating lens for refracting the unpolarized light beam generated from the light-emitting element so that it is parallel to the optical axis and directed toward the polarization conversion element.

[0011] The above light source module may further include a light irradiation lens for uniformly irradiating the polarized light beam focused by the lens array along the optical axis.

[0012] The number of the plurality of light-emitting elements and the number of the plurality of conversion units may be the same.

[0013] Among the plurality of conversion units, the first plate and the second plate of the first conversion unit and the first plate and the second plate of the second conversion unit can be arranged at 45 degrees in different directions with respect to the optical axis.

[0014] The distance between the first plate and the second plate of the first conversion unit and the first plate and the second plate of the second conversion unit may be arranged so that the distance between them increases as the polarized light beam travels along the optical axis.

[0015] The first plate of the first conversion unit and the first plate of the second conversion unit may be arranged on the inside, and the second plate of the first conversion unit and the second plate of the second conversion unit may be arranged on the outside.

[0016] The polarization separation layer may include a reflective polarizing mirror (RPM) layer and a polarized beam splitter (PBS) layer, and the polarization conversion layer may include a half wave plate (HWP) layer.

[0017] The effects of the polarization conversion element according to the present disclosure and the light source module including the same are described as follows.

[0018] According to at least one of several aspects of the present disclosure, there is an advantage in that the light utilization efficiency of a light source module can be increased by minimizing light absorption in a polarizing plate by converting the polarization of all light incident on a liquid crystal panel into linear polarization of a specific state.

[0019] According to at least one aspect of the present disclosure, there is an advantage in that the light source module can output light with a uniform brightness over a wider area than before by minimizing the spacing pitch of a plurality of lens elements uniformly arranged in a lens array provided in the light source module.

[0020] Figure 1 shows a schematic exploded view of a liquid crystal display device.

[0021] FIG. 2 illustrates a light source module according to one aspect of the present disclosure.

[0022] FIG. 3 is an enlarged view of a portion of the lens array and a portion of the polarization conversion element of the light source module of FIG. 2.

[0023] Fig. 4 is a modified example of the light source module of Fig. 2.

[0024] Fig. 5 shows an enlarged view of a portion of the light emitting element and a portion of the polarization conversion element of the light source module of Fig. 4.

[0025] Figure 6 is a table showing the light utilization efficiency of the light source modules according to Figures 2 and 4, respectively.

[0026] Fig. 7 is an image and graph showing the light distribution uniformity of the light source module according to Fig. 2 and Fig. 4, respectively.

[0027] FIG. 8 is a cross-sectional view of a light source module that can be mounted on an image generator according to one aspect of the present disclosure.

[0028] FIG. 9 illustrates a cross-sectional view of an image generator according to one aspect of the present disclosure.

[0029] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0030] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0031] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0032] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0033] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0034] Hereinafter, with reference to Fig. 1, we will briefly examine a liquid crystal display device. Fig. 1 illustrates a schematic exploded view of a liquid crystal display device.

[0035] As illustrated in FIG. 1, the liquid crystal display (100) may include a light source module (or backlight unit) (1000), a first polarizing plate (2000-1), a second polarizing plate (2000-2), a first glass plate (3000-1), a second glass plate (3000-2), and a liquid crystal panel (4000). The remaining components of the liquid crystal display (100) excluding the light source module (1000) may be referred to as a liquid crystal display module (1010). That is, the liquid crystal display (100) may be understood as a combination of the light source module (1000) and the liquid crystal display module (1010).

[0036] A first glass plate (3000-1) and a second glass plate (3000-2) can be placed on both sides of the liquid crystal panel (4000).

[0037] A first polarizing plate (2000-1) may be placed on one side of the first glass plate (3000-1) that does not come into contact with the liquid crystal panel (4000).

[0038] A second polarizing plate (2000-2) may be placed on one side of the second glass plate (3000-1) that does not come into contact with the liquid crystal panel (4000).

[0039] The polarization direction transmitting through the first polarizing plate (2000-1) and the polarization direction transmitting through the second polarizing plate (2000-2) can be orthogonal to each other.

[0040] The above light source module (1000) can be arranged to irradiate a light beam toward the first polarizing plate (2000-1).

[0041] When the above light source module (1000) irradiates a non-polarized beam to the first polarizing plate (2000-1), among the irradiated light beams, a light beam that does not match the polarization direction for transmitting the first polarizing plate (2000-1) is absorbed by the first polarizing plate (2000-1), thereby lowering the light utilization efficiency and converting it into heat, which may deteriorate the display performance.

[0042] Accordingly, the light source module (1000) may be equipped with a polarization conversion element to ensure that the entire light beam irradiated therefrom conforms to the direction of deflection for transmitting through the first polarizing plate (2000-1).

[0043] Hereinafter, a light source module having a polarization conversion element will be described with reference to FIGS. 2 and 3. FIG. 2 illustrates a light source module according to one aspect of the present disclosure, and FIG. 3 illustrates an enlarged view of a portion of the lens array and a portion of the polarization conversion element of the light source module of FIG. 2, respectively.

[0044] As illustrated in FIG. 2, the light source module (1000) may include a light emitting element (1100), a collimating lens (1200), a lens array (1300), a polarization conversion element (1400), and an illumination lens (1500).

[0045] The light emitting element (1100) generates a light beam for the light source module (1000) to irradiate to the first polarizing plate (2000-1). The light beam generated by the light emitting element (1100) may be an unpolarized light beam. In FIG. 2, the number of light emitting elements (1100) is illustrated as three, but the number may be greater or less than this. The light emitting element (1100) may include a self-collimating lens separate from the collimating lens (1200).

[0046] The light beam generated from the light-emitting element (1100) can be irradiated to the collimating lens (1200). The collimating lens (1200) refracts the light beam generated from the light-emitting element (1100) so that it becomes parallel to the optical axis (or light-emitting axis) direction (Z direction).

[0047] The light beam passing through the above-mentioned collimating lens (1200) can be irradiated to the above-mentioned lens array (1300).

[0048] The lens array (1300) may include a plurality of lenses (1301, 1302, 1303) arranged at a predetermined pitch interval (d1), as illustrated in (3-1) of FIG. 3. The lens array (1300) may be configured in the form of a FEL (Fly Eye Lens). Each lens of the lens array (1300) allows the light beam to be focused onto each conversion unit (C) of the polarization conversion element (1400).

[0049] The polarization conversion element (1400) can convert an unpolarized light beam irradiated from the lens array (1300) into a polarized light beam of a specific transmission direction. The polarization conversion element (1400) and the conversion unit (C) will be described later.

[0050] The above-described converted polarized light beam can be uniformly irradiated to the first polarizing plate (2000-1) through the light irradiation lens (1500). The light irradiation lens (1500) is not necessarily required, and the above-described converted polarized light beam can be irradiated directly to the first polarizing plate (2000-1) without passing through the light irradiation lens (1500).

[0051] The above polarization conversion element (1400) will be described with reference to (3-2) of Fig. 3.

[0052] The above polarization conversion element (1400) may be provided with a plurality of conversion units (C) on a transparent substrate (SU) such as glass.

[0053] Each conversion unit (C) may include a first plate (P1), a second plate (P2), and a half-wave plate (HWP) (H). Each conversion unit (C) may have a predetermined size or a predetermined pitch interval (d2).

[0054] The first plate (P1) and the second plate (P2) may be formed to be inclined at substantially 45 degrees relative to the optical axis direction (Z direction). Accordingly, the first plate (P1) and the second plate (P2) may be parallel to each other. Here, "substantially 45 degrees" is a concept that takes into account the error margin range in the manufacturing process. That is, if the error margin range is +1 degree to -1 degree, 44 degrees to 45 degrees is a concept included in the "substantially 45 degrees".

[0055] The first plate (P1) is a kind of polarized beam splitter (PBS: Polarized Beam Splitter), and transmits a first polarized light beam (e.g., S) of a first polarization direction among the unpolarized light beams (U) focused from the lens array (1300) as is in the optical axis direction (Z direction), and reflects a second polarized light beam (e.g., P) of a second polarization direction substantially orthogonal to the first polarization direction among the unpolarized light beams (U) in a direction (X direction) substantially orthogonal to the optical axis direction (Z direction). Here, “substantially orthogonal” is a concept that takes into account the error margin range in the manufacturing process. That is, if the error margin range is +1 degree to -1 degree, 89 degrees to 91 degrees is a concept included in the “substantially orthogonal”.

[0056] The second plate (P2) can reflect the second polarized light beam (P) of the second polarization direction back in the optical axis direction (Z direction).

[0057] The above half-wave plate (H) is a type of conversion plate that can convert a second polarized light beam (P) of a second polarization direction reflected from a second plate (P2) into a first polarized light beam (S) of a first polarization direction.

[0058] Accordingly, the unpolarized light beam (U) irradiated onto the polarization conversion element (1400) can be converted into a polarized light beam of a specific polarization direction (i.e., a polarization direction for transmitting the first polarizing plate (2000-1)), and the converted polarized light beam can be irradiated onto the first polarizing plate (2000-1). Therefore, theoretically, the unpolarized light beam (U) can contribute to image generation of the liquid crystal display device without being absorbed by the first polarizing plate (2000-1). That is, the light utilization efficiency of the light source module (1000) can be significantly improved.

[0059] However, the smaller the pitch interval (d1) between the plurality of lenses (1301, 1302, 1303) of the lens array (1300), the more uniformly the polarized light beam can be irradiated to the first polarizing plate (2000-1). However, the pitch interval (d1) between the plurality of lenses (1301, 1302, 1303) is restricted by the pitch interval (d2) of the conversion unit (C) to which the light beam is irradiated from the lens array (1300).

[0060] In detail, in order for the pitch spacing (d1) between the plurality of lenses (1301, 1302, 1303) to become smaller, the pitch spacing (d2) of the conversion unit (C) must become smaller. However, in order for the pitch spacing (d2) of the conversion unit (C) to become smaller, the manufacturing cost of the polarization conversion element (1400) inevitably increases significantly due to the complex manufacturing process of the polarization conversion element (1400) (e.g., processes such as repeated polishing, deposition, cutting, and bonding). The complexity of the manufacturing process of the polarization conversion element (1400) may be proportional to the number of the plurality of conversion units (C) per unit length.

[0061] Hereinafter, a method for making the pitch interval (d1) between the plurality of lenses (1301, 1302, 1303) of the lens array (1300) more dense by modifying the structure and arrangement of the polarization conversion element (1400) within the light source module (1000) will be described with further reference to FIGS. 4 and 5. FIG. 4 is a modified example of the light source module of FIG. 2, and FIG. 5 illustrates an enlarged view of a portion of the light emitting element and a portion of the polarization conversion element of the light source module of FIG. 4, respectively.

[0062] The above light source module (5000) may include a light emitting element (5100), a collimating lens (5200), a lens array (5300), a polarization conversion element (5400), and an illumination lens (5500).

[0063] The light emitting element (5100) generates a light beam for the light source module (5000) to irradiate to the first polarizing plate (2000-1). The light beam generated by the light emitting element (5100) may be an unpolarized light beam. In FIG. 4, a pair (i.e., two) of the light emitting elements (5100) is illustrated. It is preferable that the light emitting elements (1100) are provided in one or more pairs. The light emitting element (5100) may include a separate self-collimating lens from the collimating lens (5200).

[0064] The light beam generated from the light emitting element (5100) can be irradiated to the collimating lens (5200). The collimating lens (5200) refracts the light beam generated from the light emitting element (5100) so that it becomes parallel to the optical axis direction (Z direction).

[0065] The light beam passing through the collimating lens (5200) can be irradiated to the polarization conversion element (5400) rather than the lens array (5300), unlike in FIG. 2.

[0066] The above polarization conversion element (5400) may have one conversion unit (C) per light-emitting element (1100). Each conversion unit (C) of Fig. 4 may cover a wider area in the X direction than each conversion unit (C) of Fig. 3.

[0067] The polarization conversion element (5400) can convert an unpolarized light beam irradiated from the collimating lens (5200) into a polarized light beam having a specific transmission direction. The polarized light beam can be irradiated to the lens array (5300). The polarization conversion element (5400) and the conversion unit (C) will be described later.

[0068] The lens array (5300) may be configured in the same manner as the lens array (1300) of FIG. 2. That is, although not illustrated, the lens array (5300) may include a plurality of lenses arranged at a predetermined pitch interval. The lens array (5300) may be configured in the form of a FEL (Fly Eye Lens). Each lens of the lens array (5300) allows the polarized light beam to be focused on the light irradiation lens (5500). The lens array (5300) does not need to focus the light beam on each conversion unit (C) of the polarization conversion element (1400). Therefore, the pitch interval between the plurality of lenses of the lens array (5300) can be designed to be small without being restricted by the pitch interval of the conversion unit (C). Therefore, the light beam passing through the lens array (5300) can be more uniformly irradiated on the first polarizing plate (2000-1).

[0069] The polarized light beam focused by the lens array (5300) can be uniformly irradiated to the first polarizing plate (2000-1) through the light irradiation lens (5500). The light irradiation lens (5500) is not necessarily required, and the polarized light beam can be irradiated directly to the first polarizing plate (2000-1) without passing through the light irradiation lens (5500).

[0070] The above polarization conversion element (5400) will be further described with reference to FIG. 5.

[0071] Each conversion unit (C) of the above polarization conversion element (5400) may include a first plate (P1) and a second plate (P1).

[0072] The conversion unit (C) of FIG. 5 can cover a wider area in the X direction than the conversion unit (C) of FIG. 3. That is, the total number of conversion units (C) in the polarization conversion element (5400) according to FIGS. 4 and 5 can be much smaller than the total number of conversion units (C) in the polarization conversion element (1400) according to FIGS. 2 and 3.

[0073] The first plate (P1) and the second plate (P2) may be formed to be inclined at 45 degrees with respect to the direction (Z direction) of the optical axis (A1), respectively. Accordingly, the first plate (P1) and the second plate (P2) may be parallel to each other. The normal axis (A2) of the first plate (P1) may be inclined at an angle of 45 degrees with respect to the optical axis (A1). Here, “substantially 45 degrees” is a concept that takes into account the error margin range in the manufacturing process. That is, if the error margin range is +1 degree to -1 degree, 44 degrees to 45 degrees is a concept included in the “substantially 45 degrees”.

[0074] A polarization separation layer (e.g., a reflective polarizing mirror (RPM) layer or a polarized beam splitter (PBS) layer, etc.) may be formed on the first surface (P11) facing the lens array (5300) among both surfaces of the first plate (P1).

[0075] A variable conversion layer such as a half wave plate (HWP) layer may be formed on the second surface (P12) facing the collimating lens (5200) among both sides of the first plate (P1).

[0076] An optical mirror layer may be formed on the third surface (P21) facing the lens array (5300) among both surfaces of the second plate (P2).

[0077] The above polarization conversion layer may be formed together with the optical mirror layer on the second surface (P21) of the second plate (P2) rather than the second surface (P12) of the first plate (P1).

[0078] The unpolarized light beam irradiated from the collimating lens (5200) is incident on the second surface (P12) of the first plate (P1). The unpolarized light beam passes through the second surface (P12) without being affected by the polarization conversion layer.

[0079] The above unpolarized light beam can be separated into a first polarized light beam in a first polarization direction (e.g., S polarization) and a second polarized light beam in a second polarization direction (e.g., P polarization) by the polarization separation layer of the first surface (P11).

[0080] A second polarized light beam in the second polarization direction can pass through the polarization separation layer and be irradiated along the transmission axis (A3) of the polarization separation layer. The transmission axis (A3) can be parallel to the optical axis (A1). That is, the second polarized light beam in the second polarization direction can be irradiated along the optical axis (A1).

[0081] Meanwhile, the first polarized light beam in the first polarization direction can be reflected in a direction (X direction) substantially orthogonal to the optical axis direction (Z direction) by the polarization separation layer. Here, "substantially orthogonal" is a concept that takes into account the error margin range in the manufacturing process. That is, if the error margin range is +1 degree to -1 degree, 89 degrees to 91 degrees is a concept included in the "substantially orthogonal".

[0082] A first polarized light beam in the first polarization direction can be converted into a second polarized light beam in the second polarization direction while passing through the polarization conversion layer of the second surface (P12). This is because the normal axis (A2) of the first plate (P1) is inclined at a 45 degree angle with respect to the optical axis (A1).

[0083] The second polarized light beam in the second polarization direction can be reflected by the optical mirror layer of the third surface (P21) of the second plate (P2) and irradiated parallel to the optical axis (A1).

[0084] Accordingly, all of the unpolarized light beams irradiated onto the polarization conversion element (5400) can be converted into polarized light beams of a specific polarization direction (i.e., a polarization direction for transmitting the first polarizing plate (2000-1)), and the converted polarized light beams can be irradiated onto the first polarizing plate (2000-1). Therefore, theoretically, the unpolarized light beams can contribute to image generation of the liquid crystal display device without being absorbed by the first polarizing plate (2000-1). That is, the light utilization efficiency of the light source module (1000) can be significantly improved.

[0085] In addition, the total number (or number per unit length) of the conversion units (C) in the polarization conversion element (5400) according to FIGS. 4 and 5 may be much smaller than the total number of the conversion units (C) in the polarization conversion element (1400) according to FIGS. 2 and 3. Accordingly, the manufacturing process of the polarization conversion element (5400) according to FIGS. 4 and 5 may be simpler than that of the polarization conversion element (1400) according to FIGS. 2 and 3, and thus the manufacturing cost may be lower.

[0086] In Fig. 5, two light-emitting elements (5100) are provided as an example. The two conversion units (C) for each of these may be referred to as a first conversion unit and a second conversion unit, respectively. The first plate and the second plate of the first conversion unit and the first plate and the second plate of the second conversion unit may be arranged at 45 degrees in different directions with respect to the optical axis. At this time, the distance between the first plate and the second plate of the first conversion unit and the first plate and the second plate of the second conversion unit may be arranged so as to become farther apart from each other as the direction in which the light beam travels along the optical axis increases. At this time, the first plate of the first conversion unit and the first plate of the second conversion unit may be arranged on the inside, and the second plate of the first conversion unit and the second plate of the second conversion unit may be arranged on the outside.

[0087] The performance of the light source module according to FIGS. 2 and 4 will be further described with reference to FIGS. 6 and 7. FIG. 6 is a table showing the light utilization efficiency of the light source module according to FIGS. 2 and 4, respectively, and FIG. 7 is an image and graph showing the light distribution uniformity of the light source module according to FIGS. 2 and 4, respectively.

[0088] First, with reference to Fig. 6, we will examine the light utilization efficiency of the light source module (1000, 5000).

[0089] Figure 6 shows the light utilization efficiency of the light source module (1000, 5000) with and without the polarization conversion element (1300, 5300).

[0090] As shown in Fig. 6, it was experimentally shown that when the light source module (1000, 5000) is equipped with the polarization conversion element (1300, 5300), the light utilization efficiency is improved by about two times compared to when it is not equipped.

[0091] Hereinafter, with reference to FIG. 7, the light distribution uniformity of the light source module (1000, 5000) will be examined.

[0092] (7-1) of Fig. 7 shows the light distribution uniformity according to the light source module (1000) of Fig. 2, and (7-2) of Fig. 7 shows the light distribution uniformity according to the light source module (5000) of Fig. 4.

[0093] As can be seen in Fig. 7, in terms of light distribution uniformity, the light source module (5000) of Fig. 4 is superior to the light source module (1000) of Fig. 2.

[0094] The light source module (1000, 5000) described above can be used as a picture generation unit (PGU) for a head-up display (HUD) for a vehicle. This will be described with reference to FIGS. 8 and 9. FIG. 8 is a cross-sectional view of a light source module that can be mounted on an image generator according to one aspect of the present disclosure, and FIG. 9 illustrates a cross-sectional view of an image generator according to one aspect of the present disclosure. FIG. 8 is according to the light source module (5000) of FIG. 5, and this is exemplified as being mounted on the image generator of FIG. 9. However, the present disclosure is not limited thereto.

[0095] As described above, the light source module (5000) may include the light emitting element (5100), the collimating lens (5200), the lens array (5300), the polarization conversion element (5400), and the illumination lens (5500). Since each of these components is as described above, a detailed description thereof will be omitted.

[0096] The image generator (10) may include the light source module (5000). In addition, the image generator (10) may include a generation reflection mirror (6000), an image generation lens (7000), and the liquid crystal display module (1010).

[0097] The above image generation reflection mirror (6000) can reflect a polarized light beam generated from the light source module (5000) in a direction toward the image generation lens (7000).

[0098] The above image generation lens (7000) allows the polarized light beam to be irradiated to the liquid crystal display module (1010).

[0099] The light source module (5000) and the liquid crystal display module (1010) have been described above, so detailed descriptions will be omitted.

[0100] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

Claims

1. A plurality of light-emitting elements for generating an unpolarized light beam; A polarization conversion element for converting the above unpolarized light beam into a polarized light beam in a first polarization direction; and including a lens array for focusing the polarized light beam; The above polarization conversion element has a plurality of conversion units, Each conversion unit, a first plate inclined at 45 degrees from the optical axis; and a second plate parallel to the first plate; A polarization separation layer is provided on the first side of the first plate facing the lens array, and a polarization conversion layer is provided on the second side of the first plate facing the light emitting element. A light source module having a light mirror layer on the third side of the second plate facing the lens array.

2. In paragraph 1, A light source module characterized in that the polarization separation layer transmits a polarized light beam having a first deflection direction among the unpolarized light beams toward the lens array along the optical axis, and reflects a polarized light beam having a second deflection direction among the unpolarized light beams toward the second plate along a direction orthogonal to the optical axis.

3. In paragraph 2, A light source module characterized in that the polarization conversion layer converts the reflected polarized light beam in the second deflection direction into a polarized light beam in the first deflection direction.

4. In accordance with paragraph 3, A light source module characterized in that the above optical mirror layer reflects the polarized light beam of the converted first deflection direction toward the lens array along the optical axis.

5. In paragraph 1, A light source module further comprising a collimating lens for refracting the unpolarized light beam generated from the light-emitting element parallel to the optical axis and directing it toward the polarization conversion element.

6. In paragraph 1, A light source module further comprising a light irradiation lens for uniformly irradiating the polarized light beam focused by the lens array along the optical axis.

7. In paragraph 1, A light source module characterized in that the number of the plurality of light-emitting elements and the number of the plurality of conversion units are the same.

8. In paragraph 7, A light source module characterized in that the first plate and the second plate of the first conversion unit among the plurality of conversion units and the first plate and the second plate of the second conversion unit are arranged at 45 degrees in different directions with respect to the optical axis.

9. In paragraph 8, A light source module characterized in that the distance between the first plate and the second plate of the first conversion unit and the first plate and the second plate of the second conversion unit are arranged so that they become farther apart from each other as the polarized light beam progresses along the optical axis.

10. In paragraph 9, A light source module, characterized in that the first plate of the first conversion unit and the first plate of the second conversion unit are arranged on the inside, and the second plate of the first conversion unit and the second plate of the second conversion unit are arranged on the outside.

11. In paragraph 1, The above polarization separation layer includes a RPM (Reflective polarizing mirror) layer and a PBS (Polarized Beam Splitter) layer, A light source module characterized in that the polarization conversion layer includes a HWP (Half Wave Plate) layer.

Images