JP5156550B2 - Projection display device - Google Patents

Description

  The present invention relates to a projection display apparatus that uses fourth color component light in addition to red component light, green component light, and blue component light.

  Conventionally, it has three light modulation elements corresponding to light of three colors, a cross dichroic cube that combines light emitted from the three light modulation elements, and a projection unit that projects light combined by the cross dichroic cube Projection-type image display devices are known.

  Here, the cross dichroic cube has three light incident surfaces on which light is incident and one light emitting surface from which light is emitted. Accordingly, when the light incident on the cross dichroic cube has three colors, the projection display apparatus need only have one cross dichroic cube.

On the other hand, for the purpose of improving color reproducibility and luminance, a projection display apparatus using four or more colors of light has been proposed. For example, a projection display apparatus improves color reproducibility and brightness by using orange, yellow, or cyan in addition to three colors of red, green, and blue (for example, Patent Document 1). .
JP 2002-287247 A (Claim 1, Claim 4, FIG. 1, etc.)

  Here, when the projection display apparatus has four or more colors of light, it is not possible to synthesize four or more colors of light with one cross dichroic cube. Therefore, the projection display apparatus needs to have a plurality of dichroic cubes (or cross dichroic cubes).

  For example, when four colors of light are required to be combined, the projection display apparatus obtains two combined lights obtained by combining the two colors of light, and further combines the two combined lights. Four colors of combined light are acquired. Note that the projection display apparatus may acquire combined light of three colors by acquiring combined light of three colors and combining the combined light and one color of light. The projection display apparatus may acquire four colors of combined light by acquiring combined light in which two colors of light are combined and combining the combined light and the two colors of light.

  Here, it is necessary to provide a plurality of dichroic cubes (or cross dichroic cubes) between the light modulation element and the projection means. Accordingly, the back focus of the projection unit becomes long.

  As a result, since the projection means used in the projection display apparatus using three colors of light cannot be diverted, the cost of the projection display apparatus increases as a whole.

  Therefore, the present invention has been made to solve the above-described problem, and even when using four or more colors of light, it is possible to suppress an increase in the cost of the entire apparatus. An object is to provide a display device.

  In one feature, the projection display apparatus includes a red light modulator (liquid crystal panel 50R) that modulates red component light according to a red input signal, and a green light that modulates green component light according to a green input signal. A modulation element (liquid crystal panel 50G), a blue light modulation element (liquid crystal panel 50B) that modulates blue component light in accordance with a blue input signal, and a polarization state adjustment element (polarization) that adjusts the polarization state of the fourth color component light A state adjusting element 50Ye). The projection-type image display apparatus applies the light emitted from the red light modulation element, the green light modulation element, and the blue light modulation element to the color composition unit (cross dichroic cube 60) and the polarization state adjustment element. And a control unit (control unit 220) for controlling the voltage. Of the red component light, the green component light, and the blue component light, superimposed component light, which is any color component light, enters the polarization state adjusting element together with the fourth color component light. The polarization state adjusting element transmits the superimposed component light. The polarization state adjusting element adjusts a polarization state of the fourth color component light and transmits the fourth color component light according to switching between the low voltage application state and the high voltage application state. The controller controls a refresh operation for applying a high voltage to the polarization state adjusting element.

  In the above-described feature, the red input signal, the green input signal, and the blue input signal are input every frame. The control unit performs the refresh operation for each frame.

  In the above-described feature, the superimposed component light and the fourth color component light emitted from the polarization state adjusting element are the superimposed component light of the red light modulation element, the green light modulation element, and the blue light modulation element. The light is incident on a specific light modulation element corresponding to the above. In the high voltage application state, the polarization state of the fourth color component light incident on the specific light modulation element is aligned with the superimposed component light. The control unit performs the refresh operation in a frame in which luminance should be prioritized over color reproducibility when the low voltage application state continues for a predetermined period or longer.

  In the above-described feature, the superimposed component light and the fourth color component light emitted from the polarization state adjusting element are the superimposed component light of the red light modulation element, the green light modulation element, and the blue light modulation element. The light is incident on a specific light modulation element corresponding to the above. In the high voltage application state, the polarization state of the fourth color component light incident on the specific light modulation element is different from the superimposed component light. The control unit performs the refresh operation in a frame in which priority is given to color reproducibility over luminance when the low voltage application state continues for a predetermined period or longer.

  According to the present invention, it is possible to provide a projection display apparatus that can suppress an increase in cost of the entire apparatus even when four or more colors of light are used.

  Hereinafter, a projection display apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of Embodiment]
The projection display apparatus according to the embodiment uses yellow component light in addition to red component light, green component light, and blue component light. The yellow component light is incident on the polarization adjustment element together with the green component light. The green component light and the yellow component light emitted from the polarization state adjusting element enter the green light modulation element.

  The polarization state adjusting element transmits green component light without adjusting the change state of the green component light without depending on switching between the high voltage application state and the low voltage application state. On the other hand, the polarization state adjusting element transmits the yellow component light by adjusting the change state of the yellow component light according to switching between the high voltage application state and the low voltage application state.

  The control unit controls the voltage applied to the polarization state adjusting element. Specifically, the control unit adjusts the polarization state of yellow component light by applying a high voltage or a low voltage. The control unit performs a refresh operation for applying a high voltage to the polarization state adjusting element at a predetermined timing.

  According to such a configuration, the green component light and the yellow component light emitted from the polarization state adjusting element are guided to the green light modulation element side. The light emitted from the green light modulation element is guided to the color synthesis unit. Accordingly, even when yellow component light is used in addition to red component light, green component light, and blue component light, there are three types of light incident on the color composition unit. As a result, there is no need to change the design of the projection means, and an increase in the cost of the entire apparatus can be suppressed.

  Further, the amount of yellow component light guided to the cross dichroic cube 60 is controlled according to the voltage application state of the polarization state adjusting element. Accordingly, yellow component light can be used in a case where priority is given to luminance (for example, luminance priority mode). On the other hand, in a case where priority is given to color reproducibility (for example, color reproduction priority mode), yellow component light can not be used.

  Further, the control unit controls a refresh operation for applying a high voltage to the polarization state adjusting element. Thereby, the polarization state adjusting element can be prevented from transitioning to the splay alignment state, and the alignment state of the polarization state adjusting element can be switched between the bent alignment state and the alignment alignment state. As a result, it is possible to improve the responsiveness related to the switching of the orientation state.

  In the embodiment, yellow component light is exemplified as the fourth color component light, but the fourth color component light is not limited to this. The fourth color component light may be magenta component light or cyan component light.

  In the embodiment, green component light is exemplified as the superimposed component light, but the superimposed component light is not limited to this. The superimposed component light may be red component light or blue component light.

[First Embodiment]
(Configuration of projection display device)
Hereinafter, the projection display apparatus according to the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing a projection display apparatus 100 according to the first embodiment.

  As shown in FIG. 1, the projection display apparatus 100 includes a projection lens unit 110 and an illumination unit 120. As will be described later, the projection display apparatus 100 uses yellow component light as fourth color component light in addition to red component light, green component light, and blue component light.

  The projection lens unit 110 enlarges the image light emitted from the illumination unit 120 and projects the image light on a screen (not shown).

  The illumination unit 120 includes a light source 10, a UV / IR cut filter 20, a fly-eye lens unit 30, a PBS array 40, a plurality of liquid crystal panels 50 (a liquid crystal panel 50R, a liquid crystal panel 50G, and a liquid crystal panel 50B), and a polarization. A state adjusting element 50Ye and a cross dichroic cube 60 are provided.

  The light source 10 is a UHP lamp that emits white light. That is, the light emitted from the light source 10 includes at least red component light, green component light, blue component light, and yellow component light.

  The UV / IR cut filter 20 transmits visible light components (red component light, green component light, and blue component light). The UV / IR cut filter 20 shields infrared light components and ultraviolet light components.

  The fly-eye lens unit 30 makes the light emitted from the light source 10 uniform. Specifically, the fly eye lens unit 30 includes a fly eye lens 30a and a fly eye lens 30b. The fly-eye lens 30a and the fly-eye lens 30b are each composed of a plurality of minute lenses. Each microlens condenses the light emitted from the light source 10 so that the light emitted from the light source 10 is irradiated on the entire surface of the liquid crystal panel 50.

  The PBS array 40 aligns the polarization state of the light emitted from the fly-eye lens unit 30. For example, the PBS array 40 aligns the light emitted from the fly-eye lens unit 30 with S-polarized light (or P-polarized light).

  The liquid crystal panel 50R modulates the red component light by rotating the polarization direction of the red component light. On the side where light enters the liquid crystal panel 50R, there is a polarizing plate 51R that transmits light having one polarization direction (for example, P-polarized light) and blocks light having another polarization direction (for example, S-polarized light). Provided. On the other hand, polarized light that transmits light having another polarization direction (for example, S-polarized light) and shields light having one polarization direction (for example, P-polarized light) on the side from which light is emitted from the liquid crystal panel 50R. A plate 52R is provided.

  Accordingly, when the liquid crystal panel 50R does not rotate the polarization direction of the red component light, the red component light transmitted through the polarizing plate 51R is shielded by the polarizing plate 52R, and thus the red component light is not irradiated onto the cross dichroic cube 60. On the other hand, when the liquid crystal panel 50R rotates the polarization direction of the red component light, the red component light transmitted through the polarizing plate 51R passes through the polarizing plate 52R, and thus the red component light is irradiated onto the cross dichroic cube 60. The

  Similarly, the liquid crystal panel 50G modulates the green component light and the yellow component light by rotating the polarization directions of the green component light and the yellow component light. On the side where light enters the liquid crystal panel 50G, a polarizing plate 51G that transmits light having one polarization direction and shields light having another polarization direction is provided. On the other hand, a polarizing plate 52G that transmits light having another polarization direction and shields light having one polarization direction is provided on the side from which light is emitted from the liquid crystal panel 50G.

  The liquid crystal panel 50B modulates the blue component light by rotating the polarization direction of the blue component light. A polarizing plate 51B that transmits light having one polarization direction and shields light having another polarization direction is provided on the side where the light enters the liquid crystal panel 50B. On the other hand, a polarizing plate 52B that transmits light having another polarization direction and shields light having one polarization direction is provided on the side from which light is emitted from the liquid crystal panel 50B.

  Here, each liquid crystal panel 50 may be provided with a compensation plate for improving the contrast ratio and the transmittance. Each polarizing plate may have a pre-polarizing plate that reduces the amount of light incident on the polarizing plate and the thermal burden.

  The polarization state adjusting element 50Ye modulates yellow component light by adjusting the polarization state of yellow component light. On the other hand, the polarization state adjusting element 50Ye transmits green component light without adjusting the polarization state of the green component light.

  Specifically, the polarization state adjusting element 50Ye is an element that can adjust the polarization state of linearly polarized light incident on the self element according to the state of the voltage applied to the self element. The voltage application state includes a no-voltage application state where no voltage is applied, a low voltage application state where a low voltage is applied, and a high voltage application state where a high voltage is applied.

  For example, the polarization state adjusting element 50Ye emits the linearly polarized light as it is without rotating the polarization direction of the linearly polarized light (yellow component light) incident on the self element in a high voltage application state. On the other hand, the polarization state adjusting element 50Ye rotates the polarization direction of linearly polarized light (yellow component light) incident on the element itself by approximately 90 ° and applies the polarization direction to approximately 90 ° in a low voltage application state. Is emitted.

  The amount of yellow component light transmitted through the polarizing plate 51G provided on the light exit side of the polarization state adjusting element 50Ye is controlled by adjusting the polarization state of yellow component light by the polarization state adjusting element 50Ye.

  As the polarization state adjusting element 50Ye, a notch filter type element and an edge filter type element can be considered.

  The notch filter type element can adjust only the polarization state of light having a specific wavelength band. For example, a notch filter type element adjusts only the polarization state of light having a longer wavelength band than green, that is, a yellow wavelength band. By using a notch filter type element, unnecessary light (for example, yellow component light) can be reduced.

  An edge filter type element can adjust the polarization state of light having another wavelength band without adjusting the polarization state of light having a specific wavelength band. For example, an edge filter type element adjusts the polarization state of light having a longer wavelength band and a shorter wavelength band than green without adjusting the polarization state of light having a green wavelength band. By using an edge filter type element, the color purity of light having a specific wavelength band (for example, green component light) can be increased.

  For example, as shown in FIG. 2, the polarization state adjustment element 50Ye does not rotate the polarization directions of the green component light and the yellow component light in a high voltage application state where a high voltage is applied to the polarization state adjustment element 50Ye. Transmits green component light and yellow component light.

  On the other hand, as shown in FIG. 3, the polarization state adjusting element 50Ye rotates only the polarization direction of yellow component light by 90 ° in the low voltage application state where a low voltage is applied to the polarization state adjusting element 50Ye. Transmits component light and yellow component light.

  Here, the yellow component light and the green component light emitted from the polarization adjusting element 50Ye are applied to the polarizing plate 51G. The polarizing plate 51G transmits light having one polarization direction (for example, S-polarized light) and shields light having another polarization direction (for example, P-polarized light). Accordingly, the amount of yellow component light reaching the cross dichroic cube 60 is controlled depending on whether the polarization state adjusting element 50Ye rotates the polarization direction of the yellow component light.

  Here, a case where an edge filter type element is used as the polarization state adjusting element 50Ye will be described. FIG. 4 is a diagram for explaining an edge filter type element according to the first embodiment. In FIG. 4, the vertical axis indicates the rate (transmittance) of transmitting the color component light without adjusting the polarization state of the color component light. Therefore, as the transmittance is higher, the polarization state of the color component light is not adjusted. The polarization state of the color component light is adjusted as the transmittance is lower.

  As shown in FIG. 4, the polarization state adjusting element 50Ye transmits green component light and yellow component light without adjusting the polarization state of green component light and yellow component light in a high voltage application state where a high voltage is applied. To do.

  On the other hand, the polarization state adjusting element 50Ye adjusts the polarization state of yellow component light and transmits green component light and yellow component light in a low voltage application state where a low voltage is applied.

  Here, a configuration in which the amount of yellow component light guided to the cross dichroic cube 60 is controlled will be described with reference to FIGS. 5 and 6. 5 and 6 are enlarged views in the vicinity of the polarization adjusting element 50Ye. 5 and 6 illustrate a case where the color component light is aligned with S-polarized light by the PBS array 40. FIG.

  As shown in FIG. 5, in the high voltage application state, the polarization state adjusting element 50Ye does not adjust the polarization state of the green component light and the yellow component light. Therefore, the green component light and the yellow component light are transmitted through the polarizing plate 51G.

  On the other hand, as shown in FIG. 6, in the low voltage application state, the polarization state adjusting element 50Ye adjusts the polarization state of the yellow component light. Accordingly, the green component light is transmitted through the polarizing plate 51G, while the yellow component light is shielded by the polarizing plate 51G.

  The cross dichroic cube 60 synthesizes light emitted from the liquid crystal panel 50R, the liquid crystal panel 50G, and the liquid crystal panel 50B. That is, the cross dichroic cube 60 combines the red component light emitted from the liquid crystal panel 50R, the green component light and yellow component light emitted from the liquid crystal panel 50G, and the blue component light emitted from the liquid crystal panel 50B. The cross dichroic cube 60 emits combined light (image light) including red component light, green component light, blue component light, and yellow component light to the projection lens unit 110 side.

  Returning to FIG. 1, the illumination unit 120 includes a plurality of mirror groups (mirrors 71 to 76). The mirror 71 is a mirror that reflects red component light, green component light, blue component light, and yellow component light. The mirror 72 is a dichroic mirror that reflects red component light, green component light, and yellow component light and transmits blue component light. The mirror 73 is a dichroic mirror that reflects green component light and yellow component light and transmits red component light. The mirror 74 is a mirror that reflects the blue component light and guides the blue component light to the liquid crystal panel 50B side. The mirror 75 and the mirror 76 are mirrors that reflect the red component light and guide the red component light to the liquid crystal panel 50R side.

  Moreover, the illumination unit 120 has a plurality of lens groups (lenses 81 to 85). The lens 81 is a condenser lens that collects the light emitted from the PBS array 40. The lens 82 is a condenser lens that collects the light reflected by the mirror 71. The lens 83R collimates the red component light so that the liquid crystal panel 50R is irradiated with the red component light. The lens 83G collimates the green component light so that the liquid crystal panel 50G is irradiated with the green component light. The lens 83B makes the blue component light substantially parallel so that the liquid crystal panel 50B is irradiated with the blue component light. The relay lens 84 and the relay lens 85 substantially image red component light on the liquid crystal panel 50R while suppressing the expansion of the red component light.

(Configuration of polarization adjustment element)
Hereinafter, the configuration of the polarization state adjusting element according to the first embodiment will be described with reference to the drawings. 7 to 9 are diagrams illustrating the configuration of the polarization state adjusting element 50Ye according to the first embodiment.

  As illustrated in FIGS. 7 to 9, the polarization state adjusting element 50Ye includes a pair of electrodes and a liquid crystal element provided between the pair of electrodes. The polarization state adjusting element 50Ye has three states according to the orientation of the liquid crystal element. The three states are (a) splay alignment state, (b) bent alignment state, and (c) aligned alignment state.

  As shown in FIG. 7, in (a) the splay alignment state, the alignment of the liquid crystal elements is random. When no voltage is applied to the electrode for a certain period or longer, the polarization state adjusting element 50Ye transitions to the splay alignment state. The liquid crystal element of the polarization state adjusting element 50Ye has a splay alignment when no voltage is applied.

  As shown in FIG. 8, in the (b) bent alignment state, the alignment of the liquid crystal element is bowed. When a low voltage is applied over a certain period, the polarization state adjusting element 50Ye transitions to the bent alignment state. The liquid crystal element of the polarization state adjusting element 50Ye has a bent orientation when a low voltage is applied. In the bent orientation state, the polarization state of yellow component light is adjusted.

  As shown in FIG. 9, in (c) the aligned alignment state, the alignment of the liquid crystal element is in order. When a high voltage is applied for a certain period or longer, the polarization state adjusting element 50Ye transitions to the aligned alignment state. The liquid crystal element of the polarization state adjusting element 50Ye has alignment alignment when a high voltage is applied. In the bent orientation state, the polarization state of yellow component light is not adjusted.

  Here, the alignment of the liquid crystal element near the center away from the pair of electrodes is different from the alignment in the bent alignment state shown in FIG. 8 and the alignment alignment state shown in FIG. 9 in the splay alignment state shown in FIG. Here, the liquid crystal element near the center is separated from the pair of electrodes. Therefore, the liquid crystal element near the center is inferior to the liquid crystal element near the electrode in terms of responsiveness to voltage application.

  From this background, the responsiveness related to the transition from the splay alignment state to the bent alignment state is the responsiveness related to the transition from the bent alignment state to the aligned alignment state and the response related to the transition from the aligned alignment state to the bent alignment state. It should be noted that it is worse than gender.

(Function of polarization adjustment element)
Hereinafter, the function of the polarization state adjusting element according to the first embodiment will be described with reference to the drawings. FIG. 10 is a diagram for explaining the function of the polarization state adjustment element (polarization state adjustment element 50Ye) according to the first embodiment.

  Specifically, FIG. 10 shows a combination of the polarization state adjusting element 50Ye and the polarizing plate 51G. Polarization state adjustment element Ye: Type (1) is an element that rotates only the polarization direction of yellow component light by 90 ° when a low voltage is applied. On the other hand, the polarization state adjusting element Ye: type (2) is an element that rotates only the polarization direction of yellow component light by 90 ° in a high voltage application state.

  The polarization state adjusting element 50Ye according to type (2) has a narrow-band phase difference plate that adjusts the polarization state of yellow component light without depending on the application of voltage. As described above, in the high voltage application state, since the liquid crystal element has alignment alignment, the polarization state of yellow component light is not adjusted, but the polarization state of yellow component light is adjusted by the narrow-band phase difference plate. As a result, only the polarization direction of yellow component light is adjusted in a high voltage application state.

  Polarizing plate G: Type (1) is an element that transmits light having P-polarized light and shields light having S-polarized light. The polarizing plate G: type (1) is used, for example, when light emitted from the light source 10 is aligned with P-polarized light. On the other hand, the polarizing plate G: type (2) is an element that transmits light having S polarization and shields light having P polarization. The polarizing plate G: type (2) is used, for example, when light emitted from the light source 10 is aligned with S-polarized light.

  First, in the case where the light emitted from the light source 10 is aligned with P-polarized light, considering the case of using the polarization state adjusting element Ye: type (1), the amount of yellow component light reaching the cross dichroic cube 60 is high. Maximum when voltage is applied. On the other hand, in the low voltage application state, the polarization direction of yellow component light (S-polarized light) is different from the polarization direction of green component light (P-polarized light). Shielded with light.

  Secondly, in the case where the light emitted from the light source 10 is aligned with P-polarized light, considering the case of using the polarization state adjusting element Ye: type (2), the amount of yellow component light reaching the cross dichroic cube 60 is low. Maximum when voltage is applied. On the other hand, in the high voltage application state, the polarization direction of yellow component light (S-polarized light) is different from the polarization direction of green component light (P-polarized light). ).

  Thirdly, in the case where the light emitted from the light source 10 is aligned with S-polarized light, considering the case where the polarization state adjusting element Ye: type (1) is used, the amount of yellow component light reaching the cross dichroic cube 60 is low. Maximum voltage application state. On the other hand, in the high voltage application state, the polarization direction of yellow component light (P-polarized light) is different from the polarization direction of green component light (S-polarized light). Shielded with light.

  Fourthly, in the case where the light emitted from the light source 10 is aligned with S-polarized light, considering the case where the polarization state adjusting element Ye: type (2) is used, the amount of yellow component light reaching the cross dichroic cube 60 is high. Maximum when voltage is applied. On the other hand, in the low voltage application state, the polarization direction of yellow component light (P-polarized light) is different from the polarization direction of green component light (S-polarized light). Shielded with light.

(Function of projection display device)
Hereinafter, functions of the projection display apparatus according to the first embodiment will be described with reference to the drawings. FIG. 11 is a block diagram showing functions of the projection display apparatus 100 according to the first embodiment.

  As shown in FIG. 11, the projection display apparatus 100 includes a control unit 200 including a signal receiving unit 210 and a control unit 220.

  The signal receiving unit 210 receives a video input signal. For example, the signal receiving unit 210 receives each color signal (red input signal (R signal), green input signal (G signal), and blue input signal (B signal) from a color separation block that separates the color signal from the video input signal. ) To get.

  First, the control unit 220 controls the modulation amount of each liquid crystal panel 50 (the liquid crystal panel 50R, the liquid crystal panel 50G, and the liquid crystal panel 50B) based on each color signal acquired from the signal receiving unit 210. The controller 220 outputs each color signal to each liquid crystal panel.

  Secondly, the control unit 220 controls the voltage applied to the polarization state adjusting element 50Ye. The controller 220 outputs a control signal for controlling the voltage to the polarization state adjusting element 50Ye.

  Specifically, in the case of using yellow component light (for example, the luminance priority mode), the control unit 220 outputs a control signal for applying a high voltage to the polarization state adjusting element 50Ye. As a result, the polarization state adjusting element 50Ye transitions to the aligned alignment state.

  On the other hand, in the case where yellow component light is not used (color reproduction priority mode), the control unit 220 outputs a control signal for applying a low voltage to the polarization state adjusting element 50Ye. As a result, the polarization state adjusting element 50Ye transitions to the bent alignment state.

  Furthermore, the controller 220 controls a refresh operation for applying a high voltage to the polarization state adjusting element 50Ye. The controller 220 performs a refresh operation at a predetermined timing. For example, the control unit 220 performs a refresh operation for each frame.

  Hereinafter, the timing of performing the refresh operation will be described with reference to FIG. FIG. 12 is a timing chart showing the relationship between the video input signal, the synchronization signal, and the control signal. The synchronization signal is a signal for synchronizing the frames.

  As shown in FIG. 12, the video input signals (red input signal, green input signal, and blue input signal) are input for each frame. FIG. 12 shows a period (display period) in which an image is displayed by an image input signal input every frame. A blank period is provided between display periods of each frame.

  The synchronization signal is input every frame. For example, the synchronization signal is input at the start position of the frame on the time axis.

  A control signal for applying a high voltage is output to the polarization state adjusting element 50Ye in the blank period. That is, the control unit 220 performs a refresh operation for each frame in the blank period.

(Light intensity of each color component light)
Hereinafter, the amount of each color component light will be described with reference to the drawings. FIG. 13 is a diagram illustrating the light amount of each color component light according to the first embodiment.

  Here, the amount of light emitted from the light source 10 is the product of the relative luminous sensitivity of the light emitted from the light source 10 and the energy emitted from the light source 10. The amount of light emitted from the light source 10 has a peak in the green wavelength band and the yellow wavelength band.

  As shown in FIG. 13, the relative luminous sensitivity of light emitted from the light source 10 is a ratio (relative value) of sensitivity for each wavelength with respect to the maximum sensitivity when the energy of light emitted from the light source 10 is the same. The relative luminous sensitivity of the light emitted from the light source 10 has a peak in the green wavelength band, and decreases as the wavelength increases from the green wavelength band to a longer wavelength (or shorter wavelength).

  As can be seen from the characteristics of the light emitted from the light source 10, in order to improve the brightness of an image projected on a screen (not shown), light having a red wavelength band (red component light) and green wavelength band are used. In addition to light having light (green component light) and light having blue wavelength band (blue component light), it is preferable to use light having yellow wavelength band (yellow component light).

(Function and effect)
In the first embodiment, the green component light and the yellow component light emitted from the polarization adjusting element 50Ye are guided to the liquid crystal panel 50G side. The light emitted from the liquid crystal panel 50G is guided to the cross dichroic cube 60. Accordingly, even when yellow component light is used in addition to red component light, green component light, and blue component light, there are three types of light incident on the cross dichroic cube 60. As a result, it is not necessary to change the design of the projection lens unit 110, and an increase in the cost of the entire apparatus can be suppressed.

  In the first embodiment, the polarization state adjusting element 50Ye transmits green component light without adjusting the polarization state of the green component light without depending on the voltage application state. On the other hand, the polarization state adjusting element 50Ye transmits the yellow component light by adjusting the polarization state of the yellow component light according to the voltage application state. The amount of yellow component light guided to the cross dichroic cube 60 is controlled according to whether the polarization state of yellow component light is aligned with the polarization state of green component light. Therefore, in a case where priority is given to luminance (for example, luminance priority mode), yellow component light can be used by controlling the voltage applied to the polarization state adjusting element 50Ye. On the other hand, in a case where priority is given to color reproducibility (for example, color reproduction priority mode), it is possible not to use yellow component light by controlling the voltage applied to the polarization state adjusting element 50Ye.

  In the first embodiment, the control unit 220 controls a refresh operation for applying a high voltage to the polarization state adjusting element 50Ye. Specifically, the control unit 220 performs a refresh operation for each frame in the blank period. Accordingly, the polarization state adjusting element 50Ye can be prevented from transitioning to the splay alignment state, and the alignment state of the polarization state adjusting element 50Ye can be switched between the bent alignment state and the alignment alignment state. As a result, it is possible to improve the responsiveness related to the switching of the orientation state.

[Modification 1]
Hereinafter, Modification Example 1 of the first embodiment will be described with reference to the drawings. In the following, differences from the first embodiment will be mainly described.

  In the first modification, an element that rotates only the polarization direction of yellow component light by 90 ° in a low voltage application state is used as the polarization state adjusting element 50Ye (type (1) shown in FIG. 10).

  The control unit 220 performs the refresh operation at the timing shown below without performing the refresh operation for each frame. Specifically, when the low voltage application state continues for a predetermined period or longer, the control unit 220 performs a refresh operation in a frame where priority should be given to luminance.

  The frames that should prioritize the luminance are, for example, a frame having a higher luminance than the predetermined luminance, a frame having a lower saturation than the predetermined saturation, and the like.

(Function and effect)
In the first modification, when the low voltage application state continues for a predetermined period or longer, the control unit 220 performs a refresh operation in a frame where priority should be given to luminance. The control unit 220 can perform the refresh operation while suppressing adverse effects caused by superimposition (use) of yellow component light due to application of a high voltage. Further, the processing load of the control unit 220 is reduced as compared with the case where the refresh operation is performed for each frame.

[Modification 2]
Hereinafter, Modification Example 2 of the first embodiment will be described with reference to the drawings. In the following, differences from the first embodiment will be mainly described.

  In the modification example 2, as the polarization state adjusting element 50Ye, an element that rotates only the polarization direction of yellow component light by 90 ° in a high voltage applied state (type (2) shown in FIG. 10) is used.

  The control unit 220 performs the refresh operation at the timing shown below without performing the refresh operation for each frame. Specifically, when the low voltage application state continues for a predetermined period or longer, the control unit 220 performs a refresh operation in a frame where color reproducibility should be prioritized.

  Examples of the frame in which color reproducibility should be given priority include a frame having a luminance lower than a predetermined luminance and a frame having a saturation higher than a predetermined saturation.

(Function and effect)
In the second modification, when the low voltage application state continues for a predetermined period or longer, the control unit 220 performs a refresh operation in a frame in which color reproducibility should be prioritized. The control unit 220 can perform a refresh operation while suppressing adverse effects caused by the shielding (nonuse) of yellow component light due to the application of a high voltage. Further, the processing load of the control unit 220 is reduced as compared with the case where the refresh operation is performed for each frame.

[Modification 3]
Hereinafter, Modification 3 of the first embodiment will be described with reference to the drawings. In Modification Example 3, the configuration of the polarization state adjusting element 50Ye described above will be described in detail. In the third modification, the polarization state adjusting element 50Ye has a resolution. That is, the polarization state adjusting element 50Ye is composed of a plurality of divided regions, and the voltage application state can be controlled for each divided region.

(Configuration of light modulation element)
Hereinafter, the configuration of the light modulation element according to Modification 3 will be described with reference to the drawings. FIG. 14 is a diagram illustrating a configuration of a polarization state adjusting element 50Ye according to the third modification. FIG. 14 is a diagram of the polarization state adjusting element 50Ye viewed from the light incident surface (or light exit surface) side of the polarization state adjusting element 50Ye.

  As illustrated in FIG. 14, the polarization adjustment element 50Ye includes a plurality of segments 310 and a plurality of transparent electrodes 320.

  The segments 310 are arranged in a matrix and can be regarded as four regions (region A to region D).

  In the region (region A and region B) provided in the upper half of the polarization state adjusting element 50Ye, the area of the segment 310 becomes smaller as the position of the segment 310 becomes upward. On the other hand, in the region (region C and region D) provided in the lower half of the polarization state adjusting element 50Ye, the area of the segment 310 becomes smaller as the position of the segment 310 becomes downward.

  On the other hand, in the region (region A and region D) provided in the left half of the polarization state adjusting element 50Ye, the transparent electrode 320 is provided on the left side of each segment 310. In the region (region B and region C) provided in the right half of the polarization state adjusting element 50Ye, the transparent electrode 320 is provided on the right side of each segment 310.

  Here, the segment 311-1 to the segment 311-4 are taken as an example, and the configuration of each segment 310 will be described in more detail.

  The area of the segment 311-2 provided on the upper side of the segment 311-1 is smaller than the area of the segment 311-1 by the width of the transparent electrode 322-1 connected to the segment 311-1.

  The area of the segment 311-3 provided above the segment 311-2 is smaller than the area of the segment 311-2 by the width of the transparent electrode 322-2 connected to the segment 311-2. That is, the area of the segment 311-3 is smaller than the area of the segment 311-1 by the width of the transparent electrode 322-1 and the transparent electrode 322-2.

  The area of the segment 311-4 provided on the upper side of the segment 311-3 is smaller than the area of the segment 311-3 by the width of the transparent electrode 322-3 connected to the segment 311-3. That is, the area of the segment 311-4 is smaller than the area of the segment 311-1 by the width of the transparent electrode 322-1 to the transparent electrode 322-3.

  The transparent electrode 320 is made of a transparent member and is connected to each segment 310. Further, the transparent electrode 320 is provided in a space that is vacated by reducing the area of the segment 310.

  In the region (region A and region B) provided in the upper half of the polarization state adjusting element 50Ye, the transparent electrode 320 is connected to an FPC (Flexible Printed Circuit) (not shown) provided above the polarization state adjusting element 50Ye. ing. In the region (region C and region D) provided in the lower half of the polarization state adjusting element 50Ye, the transparent electrode 320 is connected to an FPC (not shown) provided below the polarization state adjusting element 50Ye.

  In the third modification, the case where the FPC is provided above and below the polarization state adjusting element 50Ye is illustrated, but the present invention is not limited to this. Specifically, FPCs may be provided on the left and right of the polarization state adjusting element 50Ye. In this case, it is needless to say that the configuration shown in FIG.

  In the third modification, the polarization state adjustment element 50Ye is illustrated as an example of the light modulation element having the configuration illustrated in FIG. 14, but each liquid crystal panel 50 may have the configuration illustrated in FIG. Of course.

(Function and effect)
In the third modification, in the case where it is not preferable to route the transparent electrode 320 in the thickness direction of the polarization adjustment element 50Ye, that is, in the case where it is preferable to route the transparent electrode 320 in the light incident surface (light emitting surface), the transparent electrode The space provided with 320 can be reduced efficiently. That is, the proportion of each segment 310 in the polarization state adjusting element 50Ye increases, and the modulation effect by each segment 310 can be sufficiently obtained.

  By using the transparent electrode 320 as an electrode connected to each segment 310, it is possible to suppress a decrease in light utilization efficiency due to the electrode.

  Since the FPC is provided above and below the polarization state adjusting element 50Ye, the length of the transparent electrode 320 is shortened, so that the electrical resistance of the transparent electrode 320 can be reduced and the width of the transparent electrode 320 can be reduced. Can do.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the embodiment described above, the superimposed component light superimposed on the yellow component light is green component light, but is not limited to this. The superimposed component light superimposed on the yellow component light may be red component light. In this case, the red component light is incident on the polarization state adjusting element 50Ye together with the yellow component light. However, since yellow is a complementary color of blue, it should be noted that the superimposed component light superimposed on the yellow component light is preferably not blue component light.

  In the embodiment described above, the fourth color component light is yellow component light, but is not limited to this. The fourth color component light may be cyan component light, magenta component light, or the like. Specifically, the superimposed component light superimposed on the cyan component light is preferably green component light or blue component light. The superimposed component light superimposed on the magenta component light is preferably red component light or blue component light.

  In the embodiment described above, the fourth color component light is a single color component light, but is not limited to this. The fourth color component light may be a plurality of color component lights.

  In the embodiment described above, it is assumed that the polarization state adjusting element is the polarization state adjusting element 50Ye having no resolution, but the present invention is not limited to this. Specifically, the polarization state adjusting element may be a fourth color liquid crystal panel having resolution. In this case, the resolution of the fourth color liquid crystal panel is preferably lower than the resolution of the liquid crystal panel 50R, the liquid crystal panel 50G, and the liquid crystal panel 50B in order to prevent a decrease in transmittance due to electrodes or the like. However, it should be noted that the resolution of the fourth color liquid crystal panel may be equal to the resolution of the liquid crystal panel 50R, the liquid crystal panel 50G, and the liquid crystal panel 50B.

  As the polarization state adjusting element according to the above-described embodiment, OCB (Optical Compensated Bend) liquid crystal can be used. Further, as the polarization state adjusting element, a VA (Virtual Alignment) liquid crystal or a TN (Twisted Nematic) liquid crystal may be used.

1 is a diagram illustrating a configuration of a projection display apparatus 100 according to a first embodiment. It is a figure for demonstrating the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure for demonstrating the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure for demonstrating the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is an enlarged view of the polarization state adjustment element 50Ye vicinity which concerns on 1st Embodiment. It is an enlarged view of the polarization state adjustment element 50Ye vicinity which concerns on 1st Embodiment. It is a figure which shows the structure of the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure which shows the structure of the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure which shows the structure of the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure which shows the function of the polarization state adjustment element 50Ye which concerns on 1st Embodiment. It is a figure which shows the function of the projection type video display apparatus 100 concerning 1st Embodiment. It is a timing diagram which shows the relationship between the video input signal which concerns on 1st Embodiment, a synchronizing signal, and a control signal. It is a figure which shows the light quantity of each color component light which concerns on 1st Embodiment. It is a figure which shows the structure of the polarization state adjustment element 50Ye which concerns on the modification 3 of 1st Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Light source, 20 ... UV / IR cut filter, 30 ... Fly eye lens unit, 40 ... PBS array, 50 ... Liquid crystal panel, 50Ye ... Polarization state adjustment element, 51, 52 ... Polarizing plate, 60 ... Cross dichroic cube, 71-76 ... Mirror, 81-85 ... Lens, 100 ... Projection image display device, 110 ... Projection lens unit, 120 ... Lighting unit, 200 ... Control unit, 210 ... Signal receiving unit, 220 ... Control unit, 310 ... Segment, 320 ... Transparent electrode

Claims (4)

A red light modulation element that modulates red component light according to a red input signal, a green light modulation element that modulates green component light according to a green input signal, and a blue component light according to a blue input signal A projection display apparatus comprising: a blue light modulation element; and a polarization state adjustment element that adjusts a polarization state of the fourth color component light,
A color synthesis unit that synthesizes light emitted from the red light modulation element, the green light modulation element, and the blue light modulation element;
A controller that controls a voltage applied to the polarization state adjusting element,
Of the red component light, the green component light, and the blue component light, the superimposed component light that is any color component light is incident on the polarization adjustment element together with the fourth color component light,
The polarization state adjusting element transmits the superimposed component light, and adjusts a polarization state of the fourth color component light according to switching between the low voltage application state and the high voltage application state, and the fourth color. Transmits component light,
The control unit controls a refresh operation for applying a high voltage to the polarization state adjusting element. The red input signal, the green input signal, and the blue input signal are input every frame,
The projection display apparatus according to claim 1, wherein the control unit performs the refresh operation for each frame. The superimposed component light and the fourth color component light emitted from the polarization state adjusting element are light modulations corresponding to the superimposed component light among the red light modulation element, the green light modulation element, and the blue light modulation element. Incident on a specific light modulation element,
In the high voltage application state, the polarization state of the fourth color component light incident on the specific light modulation element is aligned with the superimposed component light,
2. The projection according to claim 1, wherein the control unit performs the refresh operation in a frame in which luminance should be prioritized over color reproducibility when the low voltage application state continues for a predetermined period or longer. Type image display device. The superimposed component light and the fourth color component light emitted from the polarization state adjusting element are light modulations corresponding to the superimposed component light among the red light modulation element, the green light modulation element, and the blue light modulation element. Incident on a specific light modulation element,
In the high voltage application state, the polarization state of the fourth color component light incident on the specific light modulation element is different from the superimposed component light,
2. The projection according to claim 1, wherein the control unit performs the refresh operation in a frame in which priority is given to color reproducibility over luminance when the low voltage application state continues for a predetermined period or longer. Type image display device.

Images