JP2008165190A - Liquid crystal device, method for manufacturing the same, and electronic apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal device capable of improving the light resistance of liquid crystal, while maintaining transmittance of the liquid crystal device. <P>SOLUTION: The liquid crystal device 1 comprises a pair of substrates 10, 20; and a liquid crystal layer 50, which is interposed between the pair of substrates and contains at least one kind of additive selected from between an ultraviolet absorbent and a radical scavenger, wherein a gap between the pair of substrates is set according to the amount of the additive. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technical field of a liquid crystal device such as a liquid crystal light valve, a manufacturing method thereof, and an electronic apparatus such as a liquid crystal projector including the same.

  This type of liquid crystal device is used, for example, in a light valve (that is, a light modulation device) of a liquid crystal projector that is an example of an electronic apparatus. In the case of a light valve, extremely strong projection light is transmitted through the liquid crystal layer. Therefore, while high-intensity projection light is used under the general demand for brightening the display image, light resistance in the liquid crystal layer is important. Has been increasing. For this reason, Patent Documents 1 and 2 describe deterioration and isomerization of liquid crystal material due to light or heat by adding a light stabilizer or antioxidant such as an ultraviolet absorber to the liquid crystal material of such a liquid crystal device. Techniques for preventing this are described.

JP-A-8-176549 JP-A-62-112131

  However, according to the above-described prior art, only deterioration of the liquid crystal due to light or heat is studied, and the influence of additives such as a light stabilizer or an antioxidant on the transmittance of the liquid crystal panel, for example. No consideration has been given to. By improving the light resistance of the liquid crystal, it becomes possible to use high-intensity projection light.Thus, even if it seems that the display image can be brightened at first glance, it seems that the transmittance of the essential liquid crystal is actually lowered. There is a technical problem that it is difficult or impossible to brighten the display image.

  The present invention has been made in view of, for example, the above-described problems. For example, a liquid crystal device capable of improving the light resistance of the liquid crystal while maintaining the transmittance of the liquid crystal device used in a light valve of a liquid crystal projector. It is another object of the present invention to provide a method for manufacturing the same, and an electronic device including the same.

  In order to solve the above problems, a liquid crystal device of the present invention includes a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and containing at least one of an ultraviolet absorber or a radical scavenger as an additive, The gap between the pair of substrates is set according to the amount of the additive.

  According to the liquid crystal device of the present invention, the pair of substrates sandwich the liquid crystal layer. The liquid crystal layer contains at least one of an ultraviolet absorber or a radical scavenger as an additive. Thereby, the light resistance of a liquid crystal can be improved.

  According to the research of the present inventor, it has been found that, by adding an additive to the liquid crystal, the light resistance of the liquid crystal device is improved but the transmittance is reduced as compared with the case where no additive is added. Specifically, for example, when a 1% by weight radical scavenger is added as an additive to the liquid crystal, the light resistance is 1.5 times that of a liquid crystal device to which no additive is added. However, the transmittance is 24.2% in the liquid crystal device to which the additive is not added, whereas it is 23.7% in the liquid crystal device to which the additive is added. Here, the “transmittance” according to the present invention refers to the transmission through the liquid crystal device based on the intensity of the light measured by the illuminance measuring device without passing through the liquid crystal device to be evaluated. It is a value indicating the intensity of light as a percentage.

  According to the research of the present inventor, the transmittance can be made comparable to that of a liquid crystal device without an additive by adjusting a gap between substrates in a liquid crystal device with an additive added to the liquid crystal. Is known. Specifically, the gap between the substrates is increased by, for example, a few μm of commas. More specifically, for example, when a radical scavenger is added as an additive to the liquid crystal, the transmittance can be increased to 24.1% by increasing the inter-substrate gap by 0.1 μm.

  By the way, traditionally or generally, the gap of the liquid crystal layer is such that the desired light resistance is obtained independently of the additive or without consideration of the additive or in the absence of the additive. An additive is added to the liquid crystal layer to enhance light resistance. For this reason, even if light resistance is improved, the transmittance | permeability falls with the shadow. That is, since the gap is not set according to the amount of the additive, actually, the light resistance is improved at the expense of the transmittance due to the addition of the additive.

  Therefore, in the present invention, the gap between the pair of substrates is set according to the amount of the additive contained in the liquid crystal layer. Thereby, even if an additive is added to the liquid crystal, the transmittance of the liquid crystal device can be maintained at the same level as when no additive is added. In other words, when it is assumed that no additive is added, a transmittance higher than that in a general or traditional liquid crystal device having the gap set so as to obtain a desired light resistance is obtained. The gap according to the present invention is adjusted to the increasing side by an amount corresponding to the amount (typically, weight) of the additive. In other words, the gap when it is assumed not to be set according to the amount of the additive is adjusted to the increase side by the amount according to the amount of the additive according to the amount of the additive. As a result, the transmittance of the liquid crystal device can be maintained at the same level as when no additive is added.

  As a result, according to the liquid crystal device of the present invention, it is possible to provide a liquid crystal device capable of improving light resistance while maintaining transmittance.

  In one embodiment of the liquid crystal device of the present invention, the gap (d) is expressed by the following formula: 0.427, where Δn is the refractive index anisotropy of the liquid crystal layer and A is the weight percent of the additive. It is set so as to satisfy <(1-0.04A) × Δn × d <0.545.

  The “refractive index anisotropy (Δn)” according to the present invention is the difference between the refractive index n (||) in the major axis direction of liquid crystal molecules and the vertical refractive index n (⊥) (Δn = n (| |) -N (⊥)). According to this aspect, the transmittance of light irradiating the liquid crystal device, for example, red light (wavelength 650 nm), green light (wavelength 550 nm), and blue light (wavelength 450 nm) are all 90% or more. can do. This embodiment is particularly effective when the refractive index anisotropy Δn is about 0.18 and the temperature of the liquid crystal layer is around 40 degrees.

  In another aspect of the liquid crystal device of the present invention, the gap (d) is set so as to satisfy the following formula: 0.465 <(1−0.04A) × Δn × d <0.479.

  According to this aspect, it is possible to set the wavelengths of light irradiated to the liquid crystal device, for example, the transmittances of red light, green light, and blue light, all to 95% or more. This embodiment is particularly effective when the refractive index anisotropy Δn is about 0.18 and the temperature of the liquid crystal layer is around 40 degrees.

  In another aspect of the liquid crystal device of the present invention, the liquid crystal layer includes a TN (Twisted Nematic) liquid crystal.

  According to this aspect, it is possible to use a liquid crystal having physical properties (for example, refractive index anisotropy) that are difficult to adopt in a liquid crystal device that adopts a reflective display system.

  In another aspect of the liquid crystal device of the present invention, an image is displayed by a transmissive display method.

  According to this aspect, it is possible to use a liquid crystal having physical properties (for example, refractive index anisotropy) that are difficult to select in a liquid crystal device employing a reflective display system.

  In another aspect of the liquid crystal device of the present invention, the gap between the pair of substrates is set according to the refractive index anisotropy in addition to the amount of the additive.

  According to this aspect, since the gap between the pair of substrates is set according to the amount of the additive and the refractive index anisotropy contained in the liquid crystal layer, the refractive index anisotropic before the additive is added. More appropriate gaps can be set, taking into account the effects of gender differences.

  According to the research of the present inventor, it has been found that the rate of decrease in refractive index anisotropy when an additive is added to the liquid crystal layer depends on the refractive index anisotropy before the additive is added. Specifically, the higher the refractive index anisotropy before the addition of the additive, the higher the reduction rate of the refractive index anisotropy when the additive is added.

  Therefore, by setting the gap between the pair of substrates according to the amount of the additive and the refractive index anisotropy contained in the liquid crystal layer, the rate of decrease in the refractive index anisotropy when the additive is added Can be known more accurately. Therefore, the transmittance of the liquid crystal device can be more appropriately maintained at the same level as when no additive is added.

  In the aspect in which the gap between the pair of substrates described above is set according to the refractive index anisotropy in addition to the amount of the additive, the gap between the pair of substrates is the amount of the additive and the refractive index. In addition to anisotropy, it may be configured to be set according to the temperature of the liquid crystal layer.

  According to this structure, the gap between the pair of substrates is set according to the temperature of the liquid crystal layer in addition to the amount of the additive and the refractive index anisotropy. A more appropriate gap can be set with consideration. The “temperature of the liquid crystal layer” here is typically a temperature at the time of driving. For example, in a projector using the liquid crystal device as a light valve, a case where the liquid crystal layer is about 60 degrees Celsius is assumed. Thus, a gap between the substrates is set.

  According to the study of the present inventor, it has been found that the rate of decrease in refractive index anisotropy when an additive is added to the liquid crystal layer depends on the temperature of the liquid crystal layer. Specifically, the higher the temperature of the liquid crystal layer, the higher the rate of decrease in refractive index anisotropy when an additive is added.

  Therefore, the gap between the pair of substrates is set according to the temperature of the liquid crystal layer in addition to the amount of the additive and the refractive index anisotropy contained in the liquid crystal layer, and when the additive is added The rate of decrease in refractive index anisotropy can be known more accurately. Therefore, the transmittance of the liquid crystal device can be more appropriately maintained at the same level as when no additive is added.

  In the aspect in which the gap between the pair of substrates described above is set according to the temperature of the liquid crystal layer in addition to the amount of the additive and the refractive index anisotropy, the gap (d) is based on the temperature of the liquid crystal layer. Is set so as to satisfy the following formula: 0.427 <{Δn−A × Δn × (k × Δn−3) ÷ 100} × d <0.545. You may comprise.

  With this configuration, first, the temperature coefficient k is set based on the temperature of the liquid crystal layer. “Temperature coefficient” here is a value representing the slope when calculating the rate of decrease in refractive index anisotropy when an additive is added based on the refractive index anisotropy before the additive is added. is there. For example, assuming that the rate of decrease in refractive index anisotropy when an additive is added at a rate of 1% with respect to the liquid crystal layer is Δn (add), when the temperature of the liquid crystal layer is 20 degrees Celsius, Δn (add ) = 29 × Δn−3 is approximately established. Therefore, the temperature coefficient k in this case is '29'. Further, when the temperature of the liquid crystal layer is 60 degrees Celsius, the equation Δn (add) = 44 × Δn−3 is approximately established. Therefore, the temperature coefficient k in this case is '44'. The temperature coefficient k can be obtained by actually measuring the rate of decrease in refractive index anisotropy when an additive is added using, for example, liquid crystals having different refractive index anisotropies.

  Using the temperature coefficient k described above, the gap between the substrates is set so as to satisfy 0.427 <{Δn−A × Δn × (k × Δn−3) ÷ 100} × d <0.545. In addition, the transmittance of light irradiating the liquid crystal device, for example, red light (wavelength 650 nm), green light (wavelength 550 nm), and blue light (wavelength 450 nm) can all be 90% or more. . That is, the transmittance of the liquid crystal device can be more reliably maintained at the same level as when no additive is added.

  In the aspect in which the gap between the pair of substrates described above is set according to the temperature of the liquid crystal layer in addition to the amount of the additive and the refractive index anisotropy, the gap (d) is expressed by the following formula: 0.465 It may be configured to be set so as to satisfy <{Δn−A × Δn × (k × Δn−3) ÷ 100} × d <0.479.

  If comprised in this way, the transmittance | permeability of each of the wavelength of the light irradiated to the said liquid crystal device, for example, each of red light, green light, and blue light can be 95% or more. That is, the transmittance of the liquid crystal device can be more reliably maintained at the same level as when no additive is added.

  In order to solve the above problems, a method for manufacturing a liquid crystal device of the present invention is sandwiched between a pair of substrates and the pair of substrates, and includes at least one of an ultraviolet absorber or a radical scavenger as an additive. A method of manufacturing a liquid crystal device comprising a liquid crystal layer, the step of setting a gap between the pair of substrates according to the amount of the additive, and the step of bonding the pair of substrates with the set gap Is provided.

  According to the method for manufacturing a liquid crystal device of the present invention, it is possible to provide a liquid crystal device capable of improving light resistance while maintaining the transmittance as in the liquid crystal device of the present invention described above.

  In order to solve the above problems, an electronic device of the present invention includes the above-described liquid crystal device of the present invention (including various aspects thereof).

  The electronic apparatus according to the present invention includes the liquid crystal device according to the present invention described above, and thus can improve light resistance while maintaining the transmittance. As a result, high-quality image display can be performed, such as a projection display device, a television, a mobile phone, an electronic notebook, a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a video phone, a POS terminal, Various electronic devices such as touch panels can be realized.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1: Configuration of liquid crystal device)
First, the liquid crystal device according to the present embodiment will be described with reference to FIGS. 1 and 2. The liquid crystal device according to the present embodiment is a liquid crystal device used for a light valve of a projection display device such as a liquid crystal projector. FIG. 1 is a plan view showing the overall configuration of the liquid crystal device according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line HH ′ of FIG. Here, a TFT (Thin Film Transistor) active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of the liquid crystal device of the present invention, is taken as an example.

  1 and 2, in the liquid crystal device 1, a TFT array substrate 10 and a counter substrate 20 are disposed to face each other. Here, the TFT array substrate 10 and the counter substrate 20 according to the present embodiment are an example of “a pair of substrates” according to the present invention. The TFT array substrate 10 is made of a transparent substrate such as a quartz substrate, a glass substrate, or a silicon substrate, and the counter substrate 20 is made of a transparent substrate such as a quartz substrate or a glass substrate, for example. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  The liquid crystal layer 50 includes TN liquid crystal. The liquid crystal layer 50 includes at least one of an ultraviolet absorber or a radical scavenger as an additive to improve the light resistance of the liquid crystal layer 50.

  Here, in particular, the optical characteristics such as the transmittance of the liquid crystal device 1 and the light resistance of the liquid crystal are substantially the same with respect to the physical properties of the liquid crystal and the size of the inter-substrate gap d between the TFT array substrate 10 and the counter substrate 20. There is a trade-off relationship. That is, generally, when an attempt is made to increase optical characteristics such as transmittance, the light resistance of liquid crystals tends to be lowered, and when an attempt is made to increase light resistance of liquid crystals, optical characteristics such as transmittance tend to be lowered. Therefore, in the present embodiment, the physical properties of the liquid crystal contained in the liquid crystal layer 50 and the size of the inter-substrate gap d are determined by the results of experiments by the inventors of the present application, and the optical characteristics and light resistance of the liquid crystal device. It is set based on each of the conditions that are within a range that is not problematic from the reference. The specific properties of the liquid crystal properties and the inter-substrate gap d will be described in detail with reference to experimental results and the like to be described later.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. In the sealing material 52, a gap material 56 such as glass fiber or glass bead for spreading the inter-substrate gap d to a predetermined value is dispersed.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. Of the peripheral regions located around the image display region 10 a, the data line driving circuit 101 and the external circuit connection terminal 102 are arranged on one side of the TFT array substrate 10 in the region located outside the seal region where the sealing material 52 is disposed. It is provided along. A power source and various signals for driving the liquid crystal device 1 are supplied to the liquid crystal device 1 through an external circuit connection terminal 102 electrically connected to an external circuit. As a result, the liquid crystal device 1 enters an operating state. Note that the liquid crystal device 1 according to the present embodiment employs a transmissive display system, and when the liquid crystal device 1 operates, the upper surface side of the counter substrate 20 that is the upper side in FIG. 2 is the light incident surface side on which light is incident, that is, the lower side in FIG. 2, that is, the lower surface side of the TFT array substrate 10 when viewed from the liquid crystal layer 50 is the light emitting surface side from which transmitted light transmitted through the liquid crystal device 1 is emitted. .

  The scanning line driving circuit 104 is provided so as to be covered with the frame light-shielding film 53 inside the seal region along two sides adjacent to the one side. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10 a in this way, a plurality of the pixel lines are covered along the remaining side of the TFT array substrate 10 and covered with the frame light shielding film 53. Wiring 105 is provided. On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  On the TFT array substrate 10, a lead wiring 90 is formed for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like. .

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which pixel switching TFTs as drive elements, wiring lines such as scanning lines and data lines are formed is formed. In the image display area 10a, pixel electrodes 9a are provided in a matrix on the upper layer of wiring such as pixel switching TFTs, scanning lines, and data lines. An alignment film is formed on the pixel electrode 9a. On the other hand, a light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. On the light shielding film 23, a counter electrode 21 made of a transparent material such as ITO is formed in a solid shape so as to face the plurality of pixel electrodes 9a. An alignment film is formed on the counter electrode 21.

  Although not shown here, on the TFT array substrate 10, in addition to the data line driving circuit 101 and the scanning line driving circuit 104, the image signal on the lead wiring 90 is driven by the data line driving circuit 101. A sampling circuit that samples and supplies the data to the data line, an inspection circuit for inspecting the quality, defects, etc. of the liquid crystal device during manufacture or at the time of shipment may be formed.

(2: Relationship between physical properties of liquid crystal and gap between substrates)
Next, the relationship between the physical property values of the liquid crystal contained in the liquid crystal layer 50 and the inter-substrate gap d will be described in detail with reference to FIGS. FIG. 3 shows the rate of decrease in the refractive index anisotropy (Δn) of the liquid crystal when the inventor changes the amount (weight percent) of the additive added to the liquid crystal while keeping the gap d between the substrates constant. It is the graph which showed an example of the result of actual measurement. In FIG. 3, diamonds and square points are actually measured values when the temperature of the liquid crystal is 20 degrees Celsius and 40 degrees Celsius, respectively. Solid lines and broken lines are approximate straight lines based on the actually measured values, respectively. In the present embodiment, as an example of the “radical scavenger” of the present invention, a case where a phenol compound is added will be described as an example. In addition to the above-described phenol compounds, for example, amine compounds, phosphorus compounds, and sulfur compounds can also be used. Furthermore, as an example of the “ultraviolet absorber” of the present invention, benzophenone, benzotriazole, or the like can be used.

According to the research of the present inventors, it has been found that the transmittance of the liquid crystal device generally tends to increase as the refractive index anisotropy (Δn) of the liquid crystal increases. Therefore, as shown in FIG. 3, it can be seen that the transmittance decreases as the amount of the additive added to the liquid crystal increases. The refractive index anisotropy (Δn) is also calculated from the following formulas (1) and (2) indicating the transmittance I _out .

ここで、式（１）及び（２）において、λは光の波長であり、ｄは基板間ギャップである。

Here, in equations (1) and (2), λ is the wavelength of light, and d is the inter-substrate gap.

  Next, the relationship between the inter-substrate gap d and the transmittance will be theoretically considered with reference to FIG. 4 and the above-described equations (1) and (2). FIG. 4 is a graph of the transmittance corresponding to the retardation (Δn · d) in the liquid crystal layer 50 calculated based on the equations (1) and (2), using the wavelength of the light irradiated to the liquid crystal device 1 as a parameter. Is. In FIG. 4, red light R (wavelength 650 nm), green light G (wavelength 550 nm), and blue light B (wavelength 450 nm) are exemplified as wavelengths of light irradiated to the liquid crystal device 1.

  As shown in FIG. 4 and formulas (1) and (2), the transmittance at each wavelength depends on the retardation (Δn · d). For example, the green light G has the maximum transmittance when the retardation (Δn · d) is 0.45 (the position of the dotted line in FIG. 4). Therefore, in the design of the liquid crystal layer 50, which is usually a TN liquid crystal, the retardation (Δn · d) in the green light G that is relatively more visible to the human eye than the red light R and the blue light B is Ideally it is 0.45.

  However, in actuality, for example, in consideration of variations due to mechanical accuracy in the manufacturing process of the liquid crystal device, the transmittances of the red light R, the green light G, and the blue light B are preferably 90% or more. More preferably, the transmittance of each of the red light R, the green light G, and the blue light B is 95% or more so that the range of 427 <Δn · d <0.545 is satisfied. 0.465 <Δn · d < The liquid crystal layer 50 is designed to be in the range of 0.479.

  Incidentally, as shown in FIG. 3, the rate of decrease in refractive index anisotropy (Δn) and the amount of additive added to the liquid crystal have a linear function relationship. Assuming that the refractive index anisotropy after adding the additive is Δn ′ and the weight percentage of the additive is A, Δn ′ = (1−0.03A) Δn at 20 degrees Celsius, and at 40 degrees Celsius, Δn ′ = (1−0.04A) Δn.

  When the liquid crystal device 1 is used for a light valve of a projection type display device such as a liquid crystal projector, the liquid crystal device 1 becomes a high temperature, so that the refractive index anisotropy (Δn) is decreased at 40 degrees Celsius and added to the liquid crystal Considering the relational expression of the amount of the additive and the retardation (Δn · d), the range in which the transmittance of each of the red light R, the green light G, and the blue light B is 90% or more is 0.427 < (1-0.04A) Δn · d <0.545, and the range in which the transmittance of each of the red light R, the green light G, and the blue light B is 95% or more is 0.465 <(1-0. 04A) Δn · d <0.479.

  As described above, according to the liquid crystal device according to the present embodiment, the refractive index anisotropy (Δn) of the liquid crystal and the inter-substrate gap d have a trade-off between the transmittance and the light resistance of the liquid crystal device. Since it is set in consideration, the light resistance can be improved while maintaining the transmittance of the liquid crystal device, that is, the light utilization efficiency.

  Subsequently, modified examples of the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 5 is a graph showing the relationship between the additive amount and the refractive index anisotropy Δn for each initial value of Δn and the temperature of the liquid crystal layer. FIG. 6 is a graph showing the relationship between the initial value of Δn and the decrease rate of Δn when an additive is added when the temperature of the liquid crystal layer is 20 degrees Celsius. FIG. 7 shows the temperature of the liquid crystal layer. It is a graph which shows the relationship between the initial value of (DELTA) n, and the fall rate of (DELTA) n when an additive is added in the case where is 60 degrees Celsius.

  In FIG. 5, using a liquid crystal having an initial value of refractive index anisotropy Δn (ie, a value before adding an additive) of 0.18 and a liquid crystal of 0.15, respectively, 20 degrees Celsius and 60 degrees Celsius. Consider the case where the amount of additive is changed under the condition of the degree. As described above, the refractive index anisotropy Δn decreases as the addition amount increases. Here, both the liquid crystal having the refractive index anisotropy Δn of 0.18 and the liquid crystal having the refractive index anisotropy of 0.15 are 60 degrees Celsius. The amount that decreases with the degree increases. From this result, it can be seen that the higher the temperature of the liquid crystal layer 50, the higher the reduction rate of the refractive index anisotropy Δn when the additive is added.

  Further, when comparing the liquid crystal having a refractive index anisotropy Δn of 0.18 and the liquid crystal having a refractive index of 0.15 under the same temperature condition, a liquid crystal having a refractive index anisotropy Δn of 0.18. In this case, the amount by which the refractive index anisotropy Δn decreases is larger. From this result, it can be seen that the higher the initial value of the refractive index anisotropy Δn, the higher the decrease rate of the refractive index anisotropy Δn when the additive is added.

  As shown in FIGS. 6 and 7, the relationship between the initial value of the refractive index anisotropy Δn and the decreasing rate of the refractive index anisotropy Δn when the additive is added by 1% by weight can be expressed as a linear function. It is. For example, when the initial value of the refractive index anisotropy Δn is x and the decrease rate of the refractive index anisotropy Δn is y, as shown in FIG. 6, when the temperature of the liquid crystal layer 50 is 20 degrees Celsius, y = The expression 29x-3 is approximately established. Further, as shown in FIG. 7, when the temperature of the liquid crystal layer 50 is 60 degrees Celsius, the equation y = 44x−3 is approximately established. That is, it can be considered that there is a relationship expressed by the equation y = kx−3 between x and y using a temperature coefficient k that varies with temperature. Using this equation, Δn ′ is obtained as the refractive index anisotropy after the addition of the additive, and Δn ′ = Δn−A × Δn × (kx−3) ÷ 100.

  From the above results, for example, in order to set the respective transmittances of the red light R, the green light G and the blue light B to 90% or more, 0.427 <{Δn−A × Δn × (k × Δn−3) The inter-substrate gap d may be set within a range of ÷ 100} × d <0.545. More preferably, 0.465 <{Δn−A × Δn × (k × Δn−3) / ÷ such that the transmittance of each of the red light R, the green light G, and the blue light B is 95% or more. The inter-substrate gap d may be set within the range of 100} × d <0.479.

  For example, when the liquid crystal device 1 is used for a light valve of a projection display device such as a liquid crystal projector, the temperature of the liquid crystal layer 50 is considered to rise to around 60 degrees Celsius. Therefore, in such a case, 0.427 <{Δn−A × Δn × (44 × Δn−3) ÷ 100} × d <0.545 using the result in the case of 60 degrees Celsius described above. More preferably, the inter-substrate gap d may be set within the range of 0.465 <{Δn−A × Δn × (44 × Δn−3) ÷ 100} × d <0.479.

  On the other hand, for example, in the case of a direct-view display that does not use powerful light source light or uses only natural light, such as a projector, the room temperature is lower than 60 degrees Celsius, depending on the application and usage conditions. Alternatively, the inter-substrate gap d may be set on the premise of room temperature or a temperature close to these.

  As described above, according to the modification of the liquid crystal device according to the present embodiment, the influence between the temperature of the liquid crystal layer 50 and the influence of the difference in the initial value of the refractive index anisotropy Δn are taken into account. Since the gap d is set, the light resistance can be improved more appropriately while maintaining the transmittance of the liquid crystal device, that is, the light use efficiency.

<Electronic equipment>
Next, a case where a projector which is an example of an electronic apparatus is applied to the liquid crystal device described above will be described with reference to FIG. The liquid crystal device described above is used as a light valve of a projector. FIG. 5 is a plan view showing a configuration example of the projector. As shown in FIG. 8, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G have the same configuration as that of the above-described liquid crystal device, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit, respectively. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R, 1110B.

  Since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 8, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook , Calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention or the spirit of the invention that can be read from the entire claims and the specification, and the liquid crystal accompanying such a change. The apparatus, the manufacturing method thereof, and the electronic apparatus equipped with the apparatus are also included in the technical scope of the present invention.

It is a top view which shows the whole structure of a liquid crystal device. It is the HH 'sectional view taken on the line of FIG. It is the graph which showed an example of the relationship between the quantity of the additive added to the liquid crystal, and the decreasing rate of the refractive index anisotropy ((DELTA) n) of a liquid crystal. It is the graph which computed the transmittance | permeability corresponding to the retardation ((DELTA) n * d) in a liquid crystal layer based on a theoretical formula. It is a graph which shows the relationship between additive amount and refractive index anisotropy (DELTA) n for every initial value of (DELTA) n, and the temperature of a liquid crystal layer. It is a graph which shows the relationship between the initial value of (DELTA) n, and the fall rate of (DELTA) n when an additive is added when the temperature of a liquid crystal layer is 20 degreeC. It is a graph which shows the relationship between the initial value of (DELTA) n and the fall rate of (DELTA) n when an additive is added when the temperature of a liquid crystal layer is 60 degreeC. It is a top view which shows the structure of the projector provided with the liquid crystal device which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 9a ... Pixel electrode, 10 ... TFT array substrate, 10a ... Image display area, 20 ... Counter substrate, 21 ... Counter electrode, 23 ... Light shielding film, 50 ... Liquid crystal layer, 52 ... Sealing material, 53 ... Frame Light-shielding film, 90 ... Lead wiring, 101 ... Data line drive circuit, 102 ... External circuit connection terminal, 104 ... Scanning line drive circuit, 106 ... Vertical conduction terminal, 107 ... Vertical conduction material

Claims (11)

A pair of substrates;
A liquid crystal layer sandwiched between the pair of substrates and containing at least one of an ultraviolet absorber or a radical scavenger as an additive,
The gap between the pair of substrates is set according to the amount of the additive. The gap (d) is
When the refractive index anisotropy of the liquid crystal layer is Δn and the weight percent of the additive is A, the following formula:
0.427 <(1-0.04A) × Δn × d <0.545
The liquid crystal device according to claim 1, wherein the liquid crystal device is set so as to satisfy The gap (d) is represented by the following formula:
0.465 <(1-0.04A) × Δn × d <0.479
The liquid crystal device according to claim 1, wherein the liquid crystal device is set so as to satisfy 4. The liquid crystal device according to claim 1, wherein the liquid crystal layer includes TN (twisted nematic) liquid crystal. 5. The liquid crystal device according to any one of claims 1 to 4, wherein an image is displayed by a transmissive display method.   6. The liquid crystal device according to claim 1, wherein a gap between the pair of substrates is set according to the refractive index anisotropy in addition to the amount of the additive. .   The liquid crystal device according to claim 6, wherein the gap between the pair of substrates is set according to the temperature of the liquid crystal layer in addition to the amount of the additive and the refractive index anisotropy. The gap (d) is
When the temperature coefficient set based on the temperature of the liquid crystal layer is k, the following equation:
0.427 <{Δn−A × Δn × (k × Δn−3) ÷ 100} × d <0.545
The liquid crystal device according to claim 7, wherein the liquid crystal device is set so as to satisfy the following. The gap (d) is represented by the following formula:
0.465 <{Δn−A × Δn × (k × Δn−3) ÷ 100} × d <0.479
The liquid crystal device according to claim 7, wherein the liquid crystal device is set so as to satisfy the following. A method of manufacturing a liquid crystal device comprising a pair of substrates and a liquid crystal layer sandwiched between the pair of substrates and containing at least one of an ultraviolet absorber or a radical scavenger as an additive,
Setting a gap between the pair of substrates according to the amount of the additive;
And a step of bonding the pair of substrates with the set gap.   An electronic apparatus comprising the liquid crystal device according to claim 1.

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