JP2019158964A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of reducing absorption loss in a color filter. A liquid crystal display device DSP includes a wavelength selection layer 3 arranged between a lighting device BL and a color filter layer 22. The illuminating device BL irradiates the polarized white light toward the color filter layer. The wavelength selection layer 3 includes a reflective polarizing plate 32 and red, green, and blue phasers 33R, 33G, and 33B arranged between them. The green phase element 33G is arranged at a position corresponding to the green filter 22G, and the green component (G) passes through the reflective polarizing plate 32 and the red component (R) and the blue component (B) pass through the polarization state of the incident linearly polarized light. Is changed so as to be reflected by the reflective polarizing plate 32. [Selection diagram] Fig. 3

Description

  Embodiments described herein relate generally to a display device including a color filter.

  The display device includes an electro-optical layer such as a liquid crystal layer that selectively transmits light, and a color filter layer that colors light transmitted through the electro-optical layer. For example, in the case of a red filter that is colored red, a green component and a blue component contained in white light are absorbed and only the red component is transmitted. That is, the green and blue components incident on the red filter are absorbed without being used for image display. Similarly, a blue component and a red component incident on the green filter, and a red component and a green component incident on the blue filter are absorbed without being used for displaying an image.

  In order to improve the light utilization efficiency, a liquid crystal display device with a selective reflection type cholesteric liquid crystal filter that transmits only light of a desired wavelength and actively reflects light of wavelengths other than the transmission wavelength to the backlight side is proposed. (For example, see paragraph [0048] of Patent Document 1). The selective reflection type cholesteric liquid crystal filter is a multilayer film in which an absorption type color filter and a cholesteric color filter are combined, and can convert incident light into circularly polarized light and reflect it according to the helical pitch of the cholesteric liquid crystal.

JP 2004-145327 A

  However, such a selective reflection type cholesteric liquid crystal filter has a complicated manufacturing process and it is difficult to form a film as designed. Even if the film can be formed, the display device becomes expensive. An object of the present disclosure is to provide a display device with high light utilization efficiency and excellent price competitiveness.

A display device according to an embodiment includes a color filter layer, an illumination device, and a wavelength selection layer. The illumination device irradiates the color filter layer with mixed color light including the polarized first color component and the polarized second color component. The wavelength selection layer is disposed between the illumination device and the color filter layer. The color filter layer includes a first color filter and a second color filter. The first color filter transmits the first color component and absorbs the second color component. The second color filter transmits the second color component and absorbs the first color component.
The wavelength selection layer includes a phase retarder layer and a reflective polarizing plate. The reflective polarizing plate is disposed between the retarder layer and the color filter layer. The phase retarder layer includes a first color phase retarder formed at a position corresponding to the first color filter. The first color phase shifter changes the polarization state of the mixed color light incident on the first color phase shifter so that the first color component is transmitted through the reflective polarizer and the second color component is reflected through the reflective polarizer.

FIG. 1 is a perspective view illustrating a schematic configuration of a display device common to each embodiment. FIG. 2 is a cross-sectional view illustrating a cross-sectional structure of the display device according to the first embodiment. FIG. 3 is a cross-sectional view schematically showing linearly polarized light incident on the wavelength selection layer according to the first embodiment. FIG. 4 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer and the green filter that are superimposed on the green pixel in the first embodiment. FIG. 5 is a diagram schematically illustrating transmission characteristics of the wavelength selection layer and the red filter that are superimposed on the red pixel in the first embodiment. FIG. 6 is a diagram schematically illustrating transmission characteristics of a wavelength selection layer and a blue filter that are superimposed on a blue pixel in the first embodiment. FIG. 7 is a cross-sectional view schematically showing linearly polarized light incident on the wavelength selection layer according to the second embodiment. FIG. 8 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer and the green filter that are superimposed on the green pixel in the second embodiment. FIG. 9 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer and the red filter that are superimposed on the red pixel in the second embodiment. FIG. 10 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer and the blue filter that are superimposed on the blue pixels in the second embodiment. FIG. 11 is a cross-sectional view schematically showing linearly polarized light incident on the wavelength selection layer according to the third embodiment. FIG. 12 is a diagram schematically illustrating transmission characteristics of a wavelength selection layer and a blue filter that are superimposed on a blue pixel in the third embodiment.

  Several embodiments will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those that can be easily conceived by a person skilled in the art while keeping the gist of the invention and appropriately coming into consideration are naturally included in the scope of the present invention. In addition, the drawings may be schematically represented in comparison with actual modes in order to clarify the description, but are merely examples, and do not limit the interpretation of the present invention. In each figure, reference numerals may be omitted for the same or similar elements arranged in succession. In addition, in the present specification and each drawing, components that perform the same or similar functions as those already described are denoted by the same reference numerals, and redundant detailed description may be omitted.

  Further, in this specification, “α includes A, B or C”, “α includes any of A, B and C”, “α is one selected from the group consisting of A, B and C” The expression “including” does not exclude the case where α includes a plurality of combinations of A to C unless otherwise specified. Furthermore, these expressions do not exclude the case where α includes other elements. In each embodiment, a liquid crystal display device DSP is disclosed as an example of a display device. However, each embodiment does not preclude the application of the individual technical ideas disclosed in each embodiment to other types of display devices.

  The liquid crystal display device DSP can be used for various devices such as a smartphone, a tablet terminal, a mobile phone terminal, a personal computer, a television receiver, an in-vehicle device, a game machine, and a wearable terminal.

  First, a configuration common to the embodiments will be described with reference to FIG. FIG. 1 is a perspective view showing a schematic configuration of a liquid crystal display device DSP. The liquid crystal display device DSP includes a display panel PNL, a lighting device (backlight) BL that irradiates light on the back surface of the display panel PNL, a wavelength selection layer 3 disposed between the display panel PNL and the lighting device BL, and a display. A control module CTR for controlling the operation of the panel PNL and the lighting device BL, a driving IC chip 4 for driving the display panel PNL, and a flexible circuit board FPC1, which transmits a control signal of the control module CTR to the display panel PNL and the lighting device BL FPC2.

  The display panel (liquid crystal cell) PNL is disposed between the first substrate (array substrate) SUB1, the second substrate (counter substrate) SUB2 facing the first substrate SUB1, and the first and second substrates SUB1 and SUB2. And a liquid crystal layer LC. The liquid crystal layer LC is an example of an electro-optical layer that selectively transmits light. The display panel PNL has a display area DA for displaying an image. The display panel PNL has a plurality of pixels PX arranged in a matrix in the display area DA.

  The drive IC chip 4 is mounted on the first substrate SUB1, for example. The drive IC chip 4 may be mounted on the control module CTR or the like. The flexible circuit board FPC1 connects the first board SUB1 and the control module CTR. The flexible circuit board FPC2 connects the lighting device BL and the control module CTR.

  The control module CTR sequentially receives image data for one frame to be displayed on the display area DA from a main board or the like of an electronic device in which the liquid crystal display device DSP is mounted. This image data includes information such as the display color of each pixel PX, for example. The control module CTR supplies a signal for driving each pixel PX to the driving IC chip 4 based on the received image data. Further, the control module CTR supplies a signal for driving the light source 5 to the illumination device BL based on the received image data.

  The illumination device BL is arranged so as to face the first substrate SUB1 of the display panel PNL. The illumination device BL includes a light source 5 that emits light and a light guide plate 6 on which light from the light source 5 enters. The light source 5 includes, for example, a polarized laser element 5G that emits polarized green laser light, a polarized laser element 5R that emits polarized red laser light, and a polarized laser element 5B that emits polarized blue laser light.

  The light guide plate 6 includes an emission surface (first main surface) 6A facing the first substrate SUB1, a reflection surface (second main surface) 6B opposite to the emission surface 6A, and the emission surface 6A and the reflection surface 6B. And an incident surface (end surface) 6C therebetween. A plurality of light sources 5 are arranged along the incident surface 6C. The light from the light source 5 enters the incident surface 6C, propagates through the light guide plate 6 while being reflected by the reflecting surface 6B, and is emitted from the emitting surface 6A.

The light guide plate 6 preferably has low birefringence from the viewpoint of maintaining the polarization direction of polarized light passing through the light guide plate 6. The phase difference of the light guide plate 6 is, for example, a quarter or less of the main wavelength of incident light. The light guide plate 6 is formed of, for example, a polymer having an absolute value of 3 × 10 ⁻³ or less of an intrinsic birefringence composed of a mixture or copolymer of a positive birefringent material and a negative birefringent material.

  In the mixture, a polymer with a positive intrinsic birefringence and a negative polymer are mixed in an appropriate ratio, so that when the polymer is oriented, the birefringence cancels each other, and the birefringence appears macroscopically. I won't let you. Alternatively, the mixture offsets the birefringence of the polymer by adding small molecules having a rod-like molecular shape and polarizability anisotropy to the polymer.

  In the copolymer, a monomer having a positive intrinsic birefringence and a negative monomer are copolymerized at an appropriate ratio, and anisotropy is offset within one polymer chain. As such a polymer, for example, those described in paragraphs [0043] to [0052] of Japanese Patent No. 5263377 can be used.

  The illumination device BL emits white light including a green component (G), a red component (R), and a blue component (B) toward the back surface of the display panel PNL. The green component (G), the red component (R), and the blue component (B) are examples of the first to third color components, and the white light is an example of mixed color light including light of two or more components. It is.

[First Embodiment]
FIG. 2 is a cross-sectional view showing a cross-sectional structure of the liquid crystal display device DSP of the first embodiment. The first and second substrates SUB1 and SUB2 of the display panel PNL include first and second transparent base materials 10 and 20 having translucency, respectively.

  In order to make the light transmitted through the wavelength selection layer 3 enter each corresponding color filter 22G, 22R, 22B with high positional accuracy, the thickness of the first transparent substrate 10 is preferably thin, for example, 5 to 10 μm. Since it is easy to form a base material thinly, the 1st and 2nd transparent base materials 10 and 20 are formed, for example from the translucent resin material. Note that the first and second substrates SUB1 and SUB2 may be formed of a glass material.

  The first transparent base material 10 has a first surface 10A and a second surface 10B opposite to the first surface 10A. The second transparent substrate 20 has a third surface 20A and a fourth surface 20B opposite to the third surface 20A. The first and second substrates SUB1, SUB2 are bonded together with the first surface 10A and the third surface 20A facing each other. A liquid crystal layer LC is sealed between the first and second substrates SUB1 and SUB2.

  First and second polarizing plates PL1 and PL2 are disposed on the display surface side and the back surface side of the display panel PNL, respectively. In the example shown in FIG. 2, the first polarizing plate PL1 on the back side is attached to the second surface 10B of the first substrate SUB1. The second polarizing plate PL2 on the display surface side is attached to the fourth surface 20B of the second substrate SUB2.

  The first substrate SUB1 includes a TFT layer 11 and the like that apply a voltage to the liquid crystal layer LC in addition to the first transparent substrate 10. The TFT layer 11 is formed on the first surface 10A of the first transparent substrate 10, and includes a pixel electrode, a common electrode, a scanning signal line, a video signal line, a thin film transistor, various insulating films interposed therebetween, and the like. .

  The second substrate SUB2 includes a light shielding layer 21, a color filter layer 22, and the like in addition to the second transparent base material 20. The light shielding layer 21 is formed on the third surface 20 </ b> A of the second transparent substrate 20. The aforementioned pixel PX includes, for example, subpixels SPX (green pixel SPXG, red pixel SPXR, blue pixel SPXB) corresponding to green, red, and blue, respectively, and the light shielding layer 21 defines the subpixels SPX. ing.

  The color filter layer 22 is formed on the third surface 20A of the second transparent substrate 20 and covers the third surface 20A and the light shielding layer 21. The color filter layer 22 may be formed on the fourth surface 20B or the first substrate SUB1. The light incident on the back surface of the display panel PNL is selectively transmitted to the liquid crystal layer LC and enters the color filter layer 22.

  The color filter layer 22 includes a green filter 22G disposed in the green pixel SPXG, a red filter 22R disposed in the red pixel SPXR, and a blue filter 22B disposed in the blue pixel SPXB. The green filter 22G transmits the green component (G) included in the incident light and absorbs the red component (R) and the blue component (B).

  Similarly, the red filter 22R transmits the red component (R) included in the incident light and absorbs the blue component (B) and the green component (G). The blue filter 22B transmits the blue component (B) included in the incident light and absorbs the green component (G) and the red component (R). As a result, the incident light becomes visible light of a color corresponding to the color filter layer 22 and reaches the second polarizing plate PL2.

  The present embodiment is characterized in that a wavelength selection layer (selective reflection layer) 3 is provided between the illumination device BL and the color filter layer 22. The wavelength selection layer 3 includes a reflective polarizing plate 32 and a retarder layer 33. The retarder layer 33 is opposed to the exit surface 6A of the light guide plate 6 of the illumination device BL. The reflective polarizing plate 32 is attached to the first polarizing plate PL1 of the display panel PNL. In this embodiment, since the light reuse is premised, the reflective polarizing plate is used. However, when the light is not reused, the absorption polarizing light is used instead of the reflective polarizing plate. A plate may be used.

  The phase shifter layer 33 includes at least a green phase shifter (first phase shifter) 33G. The green phase shifter 33G is arranged at a position overlapping the green pixel SPXG (green filter 22G) in the thickness direction of the display panel PNL. In the present embodiment, the phase shifter layer 33 further includes a red phase shifter (second phase shifter) 33R and a blue phase shifter (third phase shifter) 33B.

  The red phase shifter 33R is disposed at a position overlapping the red pixel SPXR (red filter 22R), and the blue phase shifter 33B is disposed at a position overlapping the blue pixel SPXB (blue filter 22B). A light shielding layer 34 may be formed between the adjacent phase shifters 33G, 33R, and 33B.

  An example of the phase shifters 33G, 33R, and 33B is a phase plate (wavelength plate) that gives linearly polarized light. Each phaser has a product (Δnd) of the refractive index anisotropy (Δn) and the thickness (d) of the phaser (hereinafter referred to as “retardation” in this specification). . For example, the green phase shifter 33G is a phase plate having a phase difference of 1590 nm, the red phase shifter 33R is a phase plate having a phase difference of 1280 nm, and the blue phase shifter 33B is a phase plate having a phase difference of 1400 nm.

  Next, the operation of the wavelength selection layer 3 will be described with reference to FIGS. Note that the red phase shifter 33R and the blue phase shifter 33B have substantially the same shape and function as the green phase shifter 33G except for the phase difference described so far. Therefore, the green phase shifter 33G will be described in detail as a representative, and the redundant description of the red phase shifter 33R and the blue phase shifter 33B will be omitted.

  The illumination device BL according to the first embodiment irradiates linearly polarized light having parallel polarization directions. The white light emitted from the exit surface 6A of the light guide plate 6 includes a green component (G), a red component (R), and a blue component.

  When the polarization direction of the linearly polarized light emitted from the exit surface 6A of the light guide plate 6 is orthogonal to the polarization axis of the reflective polarizing plate 32, the green phase shifter 33G changes the polarization direction of the green component (G) by approximately 90 °. On the other hand, the green phase shifter 33G hardly changes the polarization directions of the red component (R) and the blue component (B).

  Further, when the polarization direction of the linearly polarized light emitted from the exit surface 6A of the light guide plate 6 and the polarization axis of the reflective polarizing plate 32 are parallel, the green phase shifter 33G hardly changes the polarization direction of the green component (G). On the other hand, the green phase shifter 33G changes the polarization directions of the red component (R) and the blue component (B) by approximately 90 °.

  As a result, in the white light incident on the green phase shifter 33G, the green component (G) is transmitted to the reflective polarizer 32, and the red component (R) and the blue component (B) are reflected to the reflective polarizer 32. The polarization state changes. The red component (R) and the blue component (B) reflected by the reflective polarizing plate 32 are returned to the light guide plate 6 and reused.

  The red component (R) and the blue component (B) reflected by the green pixel SPXG move in the width direction of the sub-pixel SPX in the optical path that is incident on the light guide plate 6 and is emitted again. The reused red component (R) and blue component (B) are incident on a subpixel SPX (for example, red pixel SPXR) different from the reflected subpixel SPX.

  Similarly to the green phase shifter 33G, the red phase shifter 33G is configured such that the red component (R) is transmitted to the reflective polarizing plate 32 and the blue component (B) and the green component (G) are reflected to the reflective polarizing plate 32. To change the polarization state of the incident light. The blue phase shifter 33 </ b> B changes the polarization state of incident light so that the blue component (B) is transmitted through the reflective polarizing plate 32 and the green component (G) and red component (R) are reflected back into the reflective polarizing plate 32. .

  According to the present embodiment, in the green pixel SPXG, the red light component (R) and the blue color component (B) that are absorbed without being used for image display when they enter the green filter 22G are positively guided. It can be reflected and reused. Similarly, light can be reused for the red pixel SPXR and the blue pixel SPXB.

  FIG. 4 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the green filter 22G in the green pixel SPXG. A solid line indicates the transmission characteristics of the wavelength selection layer 3 (the phase shifter 33G and the reflective polarizing plate 32) superimposed on the green pixel SPXG, and a broken line indicates the transmission characteristics of the green filter 22G.

  For example, when the green component (G), the red component (R), and the blue component (B) are laser beams having a wavelength of 530 nm, a wavelength of 630 nm, and a wavelength of 470 nm, respectively, wavelength selection to be superimposed on the green pixel SPXG as shown in FIG. The transmittance of the green component (G) incident on the layer 3 is approximately 1 (approximately 100%), the transmittance of the red component (R) is approximately 0 (approximately 0%), and the transmittance of the blue component (B). The rate is about 0.1 (about 10%).

  That is, the wavelength selection layer 3 superimposed on the green pixel SPXG changes the incident light so that the transmittance of the red component (R) and the blue component (B) is smaller than the transmittance of the green component (G). The green component (G) incident on the green phase shifter 33G is transmitted through the green filter 22G and used for image display.

  On the other hand, about 1 (about 100%) of the red component (R) incident on the green phase shifter 33G is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse. Similarly, about 0.9 (about 90%) of the blue component (B) incident on the green phase shifter 33G is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse.

  FIG. 5 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the red filter 22R in the red pixel SPXR. A solid line indicates the transmission characteristics of the wavelength selection layer 3 (the phase shifter 33R and the reflective polarizer 32) superimposed on the red pixel SPXR, and a broken line indicates the transmission characteristics of the red filter 22R.

  For example, when the green component (G), the red component (R), and the blue component (B) are laser beams having a wavelength of 530 nm, a wavelength of 630 nm, and a wavelength of 470 nm, respectively, wavelength selection to be superimposed on the red pixel SPXR as shown in FIG. The transmittance of the green component (G) incident on the layer 3 is about 0.1 (about 10%), the transmittance of the red component (R) is about 1 (about 100%), and the blue component (B) Is approximately 0.5 (approximately 50%).

  That is, the wavelength selection layer 3 superimposed on the red pixel SPXR changes the incident light so that the transmittance of the green component (G) and the blue component (B) is smaller than the transmittance of the red component (R). The red component (R) incident on the red phase shifter 33R passes through the red filter 22R and is used for displaying an image.

  On the other hand, about 0.5 (about 50%) of the blue component incident on the red phase shifter 33R is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse. Similarly, about 0.9 (about 90%) of the green component incident on the red phase shifter 33R is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse.

  FIG. 6 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the blue filter 22B in the blue pixel SPXB. A solid line indicates the transmission characteristics of the wavelength selection layer 3 (the phase shifter 33R and the reflective polarizing plate 32) superimposed on the blue pixel SPXB, and a broken line indicates the transmission characteristics of the blue filter 22B.

  For example, when the green component (G), the red component (R), and the blue component (B) are laser beams having a wavelength of 530 nm, a wavelength of 630 nm, and a wavelength of 470 nm, respectively, wavelength selection to be superimposed on the blue pixel SPXB as shown in FIG. The transmittance of the green component (G) incident on the layer 3 is about 0.13 (about 13%), the transmittance of the red component (R) is about 0.6 (about 60%), and the blue component ( The transmittance of B) is about 1 (about 100%).

  That is, the wavelength selection layer 3 superimposed on the blue pixel SPXB changes the incident light so that the transmittance of the green component (G) and the red component (R) is smaller than the transmittance of the blue component (B). The blue component (B) incident on the blue phase shifter 33B passes through the blue filter 22B and is used for image display.

  On the other hand, about 0.87 (about 87%) of the green component (G) incident on the blue phase shifter 33B is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse. Similarly, about 0.4 (about 40%) of the red component (R) incident on the blue phase shifter 33B is reflected by the reflective polarizing plate 32 and returned to the light guide plate 6 for reuse.

  According to the liquid crystal display device DSP of the present embodiment configured as described above, the red component (R) and the blue component (B) that are absorbed without being used for displaying an image when entering the green filter 22G. Blue component (B) and green component (G) that are absorbed without being used for displaying an image if they are incident on the red filter 22R, and absorption without being used for displaying an image if they are incident on the blue filter 22B The green component (G) and the red component (R) that are generated can be positively reflected on the light guide plate 6 and reused.

  Since the light use efficiency is improved, the power consumption of the illumination device BL can be saved and the operation time of the liquid crystal display device DSP can be extended. The light quantity of the display panel PNL can be increased, and the display quality of the liquid crystal display device DSP is improved.

  In the present embodiment, light that is not used for image display is reflected by the wavelength selection layer 3 and does not enter the color filter layer 22. When the transmission band of the color filter layer 22 is narrowed, the amount of light of the display panel PNL is reduced. Therefore, in general, the green filter 22G, the red filter 22R, and the blue filter 22B partially overlap the transmission band. In particular, the transmission band of the blue filter 22B often extends to the green wavelength region as shown in FIG. When the green component (G) is incident on such a blue filter 22B, color mixing occurs and the color may become cloudy.

  However, in this embodiment, only the green component (G) is incident on the green pixel SPXG, only the red component (R) is incident on the red pixel SPXR, and only the blue component (B) is incident on the blue pixel SPXB. To do. Since light with high color purity is incident on each sub-pixel SPX, it is possible to prevent color mixing in the color filter layer 22 and reproduce vivid colors. As a result, the display quality of the liquid crystal display device DSP is improved.

  The present embodiment includes light sources 5G, 5R, and 5B that emit green laser light, red laser light, and blue laser light. Laser light emitted from a laser semiconductor or the like has an extremely narrow bandwidth compared to light emitted from an LED or the like. Since the refractive index depends on the wavelength, as the bandwidth of the green component (G), red component (R), and blue component (B) increases, the polarization direction of the light incident on the reflective polarizing plate 32 varies. Although the wavelength selection layer 3 according to this embodiment can be applied to light having a wider bandwidth than laser light, the light that is reflected and reused by the reflective polarizing plate 32 decreases as the bandwidth of each color increases.

  In this embodiment, since the green component (G), the red component (R), and the blue component (B) are laser beams, they can be efficiently selected. Therefore, light that is not used for display can be reused to the maximum, and the light use efficiency can be increased. Color reproducibility can also be enhanced by minimizing the color mixture of the color filter layer 22.

The phase retarder layer 33 according to this embodiment may be a liquid crystal layer. If the phase retarder layer 33 is composed of a liquid crystal layer, not only the green component (G), the red component (R) and the blue component (B) are selectively transmitted but also all can be shielded from light without transmitting. Since the leakage light of the liquid crystal layer LC on the display panel PNL side can be reduced, it contributes to the improvement of contrast.
In addition, various suitable effects can be obtained from this embodiment and its modifications.

  Next, the liquid crystal display device DSP of the second and third embodiments will be described. In addition, the structure which has the same or similar function as the structure demonstrated in 1st Embodiment shall attach | subject the same code | symbol, shall consider the description of 1st Embodiment corresponding, and abbreviate | omits description here. In addition, configurations other than those described below are the same as those in the first embodiment.

[Second Embodiment]
A liquid crystal display device DSP according to a second embodiment will be described with reference to FIGS. 7 and 8 to 10. In the illumination device BL according to the second embodiment, the polarization direction (second direction) of the red component (R) and the blue component (B) is orthogonal to the polarization direction (first direction) of the green component (G). This is different from the first embodiment. The reflective polarizing plate 32 is disposed so that the polarization axis is orthogonal to the polarization direction of the green component (G).

  The green component (G) is an example of a first color component, and the red component (R) is an example of a second color component. In the second embodiment, in addition to the red component (R), the blue component (B) is an example of the second color component. In the second embodiment, only the first color phase shifter (green phase shifter 33G) corresponding to the first color component (green color component (G)) is formed in the phase shifter layer 33. In other words, the phase retarder layer 33 is not formed with the red phase shifter 33R and the blue phase shifter 33B corresponding to the second color component.

  FIG. 8 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the green filter 22G in the green pixel SPXG. The upper solid line indicates the transmittance of linearly polarized light incident on the green phase shifter 33G at 90 °. The lower solid line indicates the transmittance of linearly polarized light incident on the green phase shifter 33G at 0 °.

  If the phase difference of the retarder layer 33 is large, the brightness of the reused light is greatly affected by only a slight change in the viewing angle. Even if the display screen is bright when viewed from the front, the display screen may become dark when viewed from an oblique direction. Therefore, in the second embodiment, the phase difference of the green phase shifter 33G is configured to be 265 nm that is significantly smaller than the phase shifters 33G, 33R, and 33B according to the first embodiment.

  However, in the second embodiment, the polarization directions of the red component (R) and blue component (B) are orthogonal to the polarization direction of the green component (G). For example, when the green component (G), the red component (R), and the blue component (B) are laser beams having a wavelength of 530 nm, a wavelength of 630 nm, and a wavelength of 470 nm, respectively, as shown in FIG. The transmittance of the green component (G) incident at 90 ° is about 1 (about 100%). On the other hand, the transmittance of the red component (R) incident on the green phase shifter 33G at 0 ° is about 0.95 (about 95%), and the transmittance of the blue component (B) incident on the green phase shifter 33G at 0 °. The transmittance is about 0.95 (about 95%).

  FIG. 9 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the green filter 22G in the red pixel SPXR, and FIG. 10 is a schematic diagram illustrating the transmission characteristics of the wavelength selection layer 3 and the green filter 22G in the blue pixel SPXB. FIG. In the red pixel SPXR and the blue pixel SPXB in which no phase shifter is formed, a phase difference cannot be given to each color component.

  Therefore, as shown in FIGS. 9 and 10, the green component (G) is reflected as it is by the reflective polarizing plate 32 and reused. The red component (R) and the blue component (B) are transmitted through the reflective polarizing plate 32 as they are. The blue component (B) incident on the red filter 22R and the red component (R) incident on the blue filter 22B are absorbed by the color filter layer 22 without being used for image display.

  Since the liquid crystal display device DSP of the second embodiment is configured so that the phase difference of the retarder layer 33 is small, the brightness of the display screen hardly changes even if the viewing angle changes. In the second embodiment, since the polarization direction of the green component (G) and the polarization direction of the red component (R) and the blue component (B) are orthogonal to each other, the color can be efficiently displayed even though the phase difference is small. Can be disassembled.

  The illumination device BL according to each embodiment of the present invention includes polarized laser elements 5G, 5R, and 5B that emit polarized linearly polarized light, and can freely adjust the polarization direction of each color component. The green component (G) has lower luminous efficiency than the red component (R). According to the second embodiment, it is possible to efficiently reuse the green component (G) that tends to be insufficient.

[Third Embodiment]
A liquid crystal display device DSP according to a third embodiment will be described with reference to FIGS. 11, 8, 9, and 12. In the phase shifter layer 33 according to the third embodiment, a green phase shifter 33G and a blue phase shifter 33B are formed. In other words, the red phase retarder 33 </ b> R is not formed in the phase retarder layer 33.

  Configurations other than those described above are the same as those in the second embodiment. That is, in the illumination device BL according to the third embodiment, the polarization direction (second direction) of the red component (R) and the blue component (B) is orthogonal to the polarization direction (first direction) of the green component (G). Is configured to do. The reflective polarizing plate 32 is disposed so that the polarization axis is orthogonal to the polarization direction of the green component (G). In the third embodiment, the color components (G), (R), and (B) are examples of the first to third color components, and the color phase shifters 33G, 33R, and 33B are the first to third colors. Each is an example of a phaser.

  As in the second embodiment, when white light is incident on the wavelength selection layer 3 superimposed on the green pixel SPXG, about 1 (about 100%) of the green component (G) is transmitted and used for image display, and the red color About 0.9 (about 90%) of the component (R) and the blue component (B) are returned to the light guide plate 6 and reused. When white light is incident on the wavelength selection layer 3 superimposed on the red pixel SPXR, about 1 (about 100%) of the red component (R) is transmitted and used for image display, and about 1 of the blue component (B). 1 (about 100%) is absorbed by the red filter 22R without being used for image display, and about 1 (about 100%) of the green component (G) is returned to the light guide plate 6 for reuse.

  However, the third embodiment further includes a blue phase shifter 33B corresponding to the third color component. FIG. 12 is a diagram schematically illustrating the transmission characteristics of the wavelength selection layer 3 and the blue filter 22B in the blue pixel SPXB. The solid line extending from the upper left to the lower right in FIG. 12 indicates the transmittance of linearly polarized light incident on the blue phase shifter 33B at 0 °. A solid line extending from the lower left to the upper right indicates the transmittance of linearly polarized light incident on the blue phase shifter 33B at 90 °.

  The phase difference of the blue phase shifter 33B is 463 nm. However, in the third embodiment, the polarization directions of the red component (R) and the blue component (B) are orthogonal to the polarization direction of the green component (G). For example, when the green component (G), the red component (R), and the blue component (B) are laser beams having a wavelength of 530 nm, a wavelength of 630 nm, and a wavelength of 470 nm, respectively, as shown in FIG. The transmittance of the incident blue component (B) is about 1 (about 100%), and the transmittance of the red component (R) incident on the blue phase shifter 33B at 0 ° is about 0.6 (about 60%). ). On the other hand, the transmittance of the green component (G) incident on the blue phase shifter 33B at 90 ° is about 0.2 (about 20%).

  In the third embodiment, similarly to the second embodiment, the phase difference of the retarder layer 33 is configured to be small. Even if the viewing angle changes, the brightness of the display screen hardly changes, and the display quality of the liquid crystal display device DSP is improved. Furthermore, according to the third embodiment, not only the green component (G) but also the blue component (B) can be positively returned to the light guide plate 6 and reused. Although the blue component (B) is not as high as the green component (G), the light emission efficiency is lower than that of the red component (R).

  In the second embodiment specialized for the reuse of the green component (G), about 1 (about 100%) of the green component (G) can be reused in the wavelength selection layer 3 superimposed on the blue pixel SPXB. However, in the third embodiment, the reuse of the green component (G) is about 0.8 (about 80%) in the wavelength selection layer 3 superimposed on the blue pixel SPXB.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. The configurations disclosed in the embodiments can be combined as appropriate.

  For example, the configuration of the pixel PX may further include, for example, a subpixel SPX corresponding to white or the like, or may include a plurality of subpixels SPX corresponding to the same color. When the white pixel is included, the phase shifter corresponding to the white pixel gives a phase difference so that the green component (G), the red component (R), and the blue component (B) are all transmitted through the reflective polarizing plate 32.

  3 ... wavelength selection layer, 22 ... color filter layer, 22G ... green color filter (example of first color filter), 22R ... red color filter (example of second color filter), 22B ... blue color filter, 32 ... reflective polarizing plate, 33 ... retarder layer, 33G ... green phase retarder (an example of first color phaser), 33R ... red phase retarder (an example of second color phaser), 33B ... blue phase retarder, BL ... illuminating device, DSP ... liquid crystal display Device (an example of a display device).

Claims (6)

A color filter layer;
An illumination device that emits mixed color light including a polarized first color component and a polarized second color component toward the color filter layer;
A wavelength selection layer disposed between the illumination device and the color filter layer,
The color filter layer includes a first color filter that transmits the first color component and absorbs the second color component, and a second color filter that transmits the second color component and absorbs the first color component. And comprising
The wavelength selection layer includes a retardation layer, and a reflective polarizing plate disposed between the retardation layer and the color filter layer,
The phase shifter layer includes a first color phase shifter formed at a position corresponding to the first color filter,
The first color phase shifter reflects the polarization state of the mixed color light incident on the first color phase shifter, the first color component is transmitted through the reflective polarizer, and the second color component is reflected by the reflective polarizer. A display device that changes as it is done. The first color component is a green component, and the second color component is a red component;
The lighting device further includes a polarized blue component in addition to the green component and the red component toward the color filter layer, and irradiates white light in which the polarization directions of the green component, the red component, and the blue component are parallel. And
The first color filter is a green filter that transmits the green component and absorbs the red component and the blue component,
The second color filter is a red filter that transmits the red component and absorbs the blue component and the green component;
The color filter layer further includes a blue filter that transmits the blue component and absorbs the green component and the red component,
The phaser layer further includes a red phaser formed at a position corresponding to the red filter, and a blue phaser formed at a position corresponding to the blue filter,
The first color phase shifter is a green phase shifter, and the green component is transmitted to the reflective polarizing plate and the red component and the blue component are reflected in the polarization state of the white light incident on the green phase shifter. Change it to reflect on the polarizing plate,
The red phase shifter is configured such that the red component is transmitted to the reflective polarizer and the blue component and the green component are reflected to the reflective polarizer in the polarization state of the white light incident on the red phase shifter. Change
The blue phase shifter is configured such that the blue component is transmitted to the reflective polarizing plate and the green component and the red component are reflected to the reflective polarizing plate in the polarization state of the white light incident on the blue phase shifter. The display device according to claim 1, wherein the display device is changed.   The display device according to claim 2, wherein the phase difference of the red phase shifter is 1280 nm, the phase difference of the green phase shifter is 1590 nm, and the phase difference of the blue phase shifter is 1400 nm.   2. The display device according to claim 1, wherein polarization directions of the first color component and the second color component of the mixed color light are orthogonal to each other. The first color component is a green component, and the second color component is a red component or a blue component;
The reflective polarizing plate is arranged in a direction whose polarization axis is orthogonal to the polarization direction of the green component,
The display device according to claim 4, wherein a phase difference of the first color phase shifter is 265 nm. The second color component is a red component;
The illumination device irradiates the color filter layer with white light further including a polarized blue component whose polarization direction is orthogonal to the green component in addition to the green component and the red component,
The first color filter is a green filter that transmits the green component and absorbs the red component and the blue component,
The second color filter is a red filter that transmits the red component and absorbs the blue component and the green component;
The color filter layer further includes a blue filter that transmits the blue component and absorbs the green component and the red component,
The phase retarder layer further includes a blue phase retarder formed at a position corresponding to the blue filter,
The first color phase shifter is a green phase shifter, and the green component is transmitted to the reflective polarizing plate and the red component and the blue component are reflected in the polarization state of the white light incident on the green phase shifter. Change it to reflect on the polarizing plate,
The blue phase shifter is configured such that the blue component is transmitted to the reflective polarizing plate and the green component and the red component are reflected to the reflective polarizing plate in the polarization state of the white light incident on the blue phase shifter. Change
The display device according to claim 5, wherein a phase difference of the blue phase shifter is 463 nm.

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